JP7723907B2 - Lighting device, lighting method, mobile body with lighting device, and work support device - Google Patents

Description

The present invention relates to a lighting device, a lighting method, a mobile object with a lighting device, and a work support device.

Patent Document 1 considers illuminating a linear illuminated area. The illuminated area extends in a thin, long strip away from the lighting device. Linear illumination can be used not only for decorative purposes, but also as a guide for indicating work routes or dividing areas.

WO2020/013335A1

Line illumination as a guide can be achieved by having the illuminated area pass over a target position far away from the lighting device. However, if the illuminated area does not extend close to the lighting device, it becomes unclear whether the relative position between the reference position near the lighting device and the illuminated area is appropriate. However, extending the illuminated area close to the lighting device increases the length of the illuminated area. When the illuminated area is long, it becomes difficult to illuminate brightly over a long distance.

This disclosure was made in consideration of the above points, and aims to provide bright illumination in the distance when providing line illumination from the vicinity of the lighting device to a distant area.

An illumination device according to an embodiment of the present disclosure includes:
An illumination device that illuminates an illumination area on a projection surface,
a light source that emits coherent light;
a shaping optical system that shapes the coherent light from the light source;
a diffractive optical element that diffracts the coherent light shaped by the shaping optical system and directs the light toward the illuminated area,
the illuminated area has a linear shape including a distal end far from the illumination device and a proximal end close to the illumination device;
an angle between a traveling direction of the coherent light from the illumination device toward the distal end and a normal direction of the projection surface is 60° or more;
an angle between a direction of travel of the coherent light from the illumination device toward the proximal end and the normal direction is 20° or less;
The radiation intensity in a direction from the lighting device toward one position within the illuminated area is less than the radiation intensity in a direction from the lighting device toward another position located between the one position and the distal end.

In an illumination device according to one embodiment of the present disclosure, the radiation intensity in a direction from the illumination device toward an arbitrary position within the illuminated area may be equal to or less than the radiation intensity in a direction from the illumination device toward any other position located between the arbitrary position and the distal end.

In an illumination device according to an embodiment of the present disclosure,
When the illuminated area is divided into five equal parts along its longitudinal direction, the illuminated area is divided into five sections, namely, a first section to a fifth section, from the proximal end to the distal end,
n is an integer from 1 to 4,
The radiation intensity in a direction from the lighting device towards a position in the nth zone may be equal to or less than the radiation intensity in a direction from the lighting device towards a position in the n+1th zone.

In a lighting device according to one embodiment of the present disclosure, the average value of the radiation intensity in a direction from the lighting device toward a position in the nth zone may be less than or equal to the average value of the radiation intensity in a direction from the lighting device toward a position in the n+1th zone.

In an illumination device according to an embodiment of the present disclosure,
Define an angular space coordinate system with the direction of travel of the zero-order light as the origin, the vertical angle as the vertical axis, and the horizontal angle as the horizontal axis,
The angular range of the vertical axis of a distribution region in the angular space coordinate system of the coherent light traveling from the lighting device toward the illuminated region may be larger than the angular range of the horizontal axis of the distribution region.

In an illumination device according to one embodiment of the present disclosure, the first-order light distribution region in the angular space coordinates of the first-order diffracted light diffracted by the diffractive optical element may be rectangular, or may be trapezoidal, with the width along the horizontal axis being narrower above the vertical axis than below the vertical axis.

In an illumination device according to one embodiment of the present disclosure, the radiation intensity of first-order diffracted light diffracted by the diffractive optical element in a direction from the illumination device toward one position within the illuminated region may be greater than the radiation intensity of the first-order diffracted light in a direction from the illumination device toward another position located between the one position and the proximal end.

In an illumination device according to one embodiment of the present disclosure, the radiation intensity of the first-order diffracted light in a direction from the illumination device toward an arbitrary position within the illuminated region may be equal to or greater than the radiation intensity of the first-order diffracted light in a direction from the illumination device toward any other position located between the arbitrary position and the proximal end.

In an illumination device according to an embodiment of the present disclosure,
When the illuminated area is divided into five equal parts along its longitudinal direction, the illuminated area is divided into five sections, namely, a first section to a fifth section, from the proximal end to the distal end,
n is an integer from 1 to 4,
The radiation intensity of the first-order diffracted light in a direction from the lighting device toward a position within the n+1th region may be equal to or greater than the radiation intensity of the first-order diffracted light in a direction from the lighting device toward a position within the nth region.

In an illumination device according to one embodiment of the present disclosure, the average radiation intensity of the first-order diffracted light in a direction from the illumination device toward a position within the (n+1)th zone may be equal to or greater than the average radiation intensity of the first-order diffracted light in a direction from the illumination device toward a position within the nth zone.

In an illumination device according to one embodiment of the present disclosure, the illumination device may be located within the illuminated area or on an extension of the illuminated area.

In an illumination device according to an embodiment of the present disclosure,
Define an angular space coordinate system with the direction of travel of the zero-order light as the origin, the vertical angle as the vertical axis, and the horizontal angle as the horizontal axis,
a first-order light distribution area in the angular space coordinates of the first-order diffracted light diffracted by the diffractive optical element includes the origin,
The origin may be located at a central position along the horizontal axis of the primary light distribution region at a position that corresponds to the origin on the vertical axis, or may be shifted from the central position along the horizontal axis by a length that is 20% or less of the width along the horizontal axis of the primary light distribution region at a position that corresponds to the origin on the vertical axis.

In an illumination device according to an embodiment of the present disclosure,
Define an angular space coordinate system with the direction of travel of the zero-order light as the origin, the vertical angle as the vertical axis, and the horizontal angle as the horizontal axis,
a first-order light distribution area in the angular space coordinates of the first-order diffracted light diffracted by the diffractive optical element may include the origin,
The origin may be located below a position spaced downward along the vertical axis from an upper edge of the primary light distribution region by 2/5 of the length of the primary light distribution region along the vertical axis.

In an illumination device according to an embodiment of the present disclosure,
Define an angular space coordinate system with the direction of travel of the zero-order light as the origin, the vertical angle as the vertical axis, and the horizontal angle as the horizontal axis,
a first-order light distribution area in the angular space coordinates of the first-order diffracted light diffracted by the diffractive optical element may include the origin,
The origin may be located below a center position along the vertical axis of the primary light distribution region.

In an illumination device according to an embodiment of the present disclosure,
the illuminated region may include a linear first partial region onto which first-order diffracted light diffracted by the diffractive optical element is incident, and a second partial region connected to the first partial region from the proximal end side,
The radiation intensity in a direction from the lighting device towards a position in the second partial region may be smaller than the radiation intensity in a direction from the lighting device towards a position in the first partial region.

In a lighting device according to one embodiment of the present disclosure, the radiation intensity in a direction from the lighting device toward the one position within the second partial region may be less than or equal to the radiation intensity in a direction from the lighting device toward any position within the first partial region.

In a lighting device according to one embodiment of the present disclosure, the radiation intensity in a direction from the lighting device toward any position within the second partial region may be less than or equal to the radiation intensity in a direction from the lighting device toward any position within the first partial region.

In a lighting device according to one embodiment of the present disclosure, the average radiation intensity in a direction from the lighting device toward any position within the second partial region may be less than or equal to the average radiation intensity in a direction from the lighting device toward any position within the first partial region.

In an illumination device according to an embodiment of the present disclosure,
The first subregion may include a first distal end remote from the lighting device and a first proximal end close to the lighting device;
The radiation intensity in a direction from the lighting device toward one position within the first partial region may be less than the radiation intensity in a direction from the lighting device toward another position within the first partial region located between the one position and the first distal end.

In a lighting device according to one embodiment of the present disclosure, the radiation intensity in a direction from the lighting device toward an arbitrary position within the first partial region may be equal to or less than the radiation intensity in a direction from the lighting device toward any other position within the first partial region located between the arbitrary position and the first distal end.

In an illumination device according to an embodiment of the present disclosure,
When the first partial region is divided into five equal parts along its longitudinal direction, the first partial region is divided into five sections from the first proximal end to the second distal end, from the first partial section to the fifth partial section,
k is an integer from 1 to 4,
The radiation intensity in a direction from the lighting device towards a position in the kth subzone may be less than or equal to the radiation intensity in a direction from the lighting device towards a position in the k+1th subzone.

In a lighting device according to one embodiment of the present disclosure, the average value of the radiation intensity in a direction from the lighting device toward a position within the kth partial area may be less than or equal to the average value of the radiation intensity in a direction from the lighting device toward a position within the k+1th partial area.

A moving body with an illumination device according to an embodiment of the present disclosure includes:
any of the lighting devices described above;
and a moving body on which the lighting device is mounted.

A work assistance device according to an embodiment of the present disclosure includes:
any of the lighting devices described above;
a target disposed within the illuminated area.

An illumination method according to an embodiment of the present disclosure includes:
1. A lighting method for illuminating an illumination area on a projection surface using a lighting device, comprising:
illuminating a linear illumination area including a distal end far from the illumination device and a proximal end close to the illumination device;
an angle between a traveling direction of the coherent light from the illumination device toward the distal end and a normal direction of the projection surface is 60° or more;
an angle between a direction of travel of the coherent light from the illumination device toward the proximal end and the normal direction is 20° or less;
The radiation intensity in a direction from the lighting device toward one position within the illuminated area is less than the radiation intensity in a direction from the lighting device toward another position located between the one position and the distal end.

This invention allows for bright illumination of distant areas when providing line illumination from close to the lighting device.

FIG. 1 is a diagram for explaining an embodiment, and is a perspective view showing an example of a lighting device. FIG. 2 is a top view showing the lighting device shown in FIG. FIG. 3 is a side view showing the lighting device shown in FIG. FIG. 4 is a side view corresponding to FIG. 3, showing an illumination device having a different light distribution characteristic from the illumination device shown in FIG. FIG. 5 is a side view corresponding to FIG. 3, showing an illumination device that illuminates a projection surface different from the projection surface shown in FIG. FIG. 6 is a graph showing an example of the diffraction characteristics of the diffractive optical element included in the illumination device shown in FIG. 3 in angular space coordinates. FIG. 7 is a graph corresponding to FIG. 6, showing another example of the diffraction characteristics of the diffractive optical element. FIG. 8 is a side view corresponding to FIG. 3, showing an illuminated area that can be illuminated by a diffractive optical element having the diffractive properties shown in FIG. FIG. 9 is a graph corresponding to FIG. 6, showing yet another example of the diffraction characteristics of a diffractive optical element. FIG. 10 is a side view corresponding to FIG. 3, showing an illuminated area that can be illuminated by a diffractive optical element having the diffractive properties shown in FIG. FIG. 11 is a graph corresponding to FIG. 6, showing yet another example of the diffraction characteristics of a diffractive optical element. FIG. 12 is a graph corresponding to FIG. 6, showing yet another example of the diffraction characteristics of a diffractive optical element. FIG. 13 is a side view corresponding to FIG. 3, showing an illuminated area that can be illuminated by a diffractive optical element having the diffractive properties shown in FIG. FIG. 14 is a perspective view showing an example of a mobile object with an illumination device including the illumination device shown in FIG. FIG. 15A is a perspective view showing an example of an illuminated area on a projection surface. FIG. 15B is a perspective view showing another example of an illuminated area on the projection surface. FIG. 15C is a perspective view showing yet another example of the illuminated area on the projection surface. FIG. 15D is a perspective view showing yet another example of the illuminated area on the projection surface. FIG. 16 is a perspective view corresponding to FIG. 1 and showing another example of the lighting device. FIG. 17 is a perspective view showing still another example of the lighting device. FIG. 18 is a perspective view showing still another example of the lighting device. FIG. 19 is a perspective view showing still another example of the lighting device. FIG. 20 is a perspective view showing still another example of the lighting device.

One embodiment of the present disclosure will now be described with reference to the drawings. Note that in the drawings accompanying this specification, the scale and aspect ratios have been appropriately altered and exaggerated from their actual sizes for ease of illustration and understanding.

To clarify the directional relationships between drawings, some drawings use arrows to indicate the first direction D1, second direction D2, and third direction D3 as directions common to all drawings. The tip of the arrow is the first side of each direction D1, D2, and D3. An arrow pointing toward the viewer in a direction perpendicular to the plane of the drawing is indicated by a symbol with a dot in a circle, as shown in Figure 2, for example. An arrow pointing toward the viewer in a direction perpendicular to the plane of the drawing is indicated by a symbol with an x in a circle, as shown in Figure 3, for example.

Terms used in this specification that specify shapes, geometric conditions, and their degrees, such as "parallel," "perpendicular," and "same," as well as length and angle values, are not limited to their strict meanings, but are interpreted to include the range of degrees to which similar functions can be expected.

In this embodiment, the lighting device 30 illuminates an illuminated area 90 on a projection surface 95. As shown in FIG. 1, the lighting device 30 includes a light source 40, a shaping optical system 45, and a diffractive optical element 50. The light source 40 emits coherent light. The shaping optical system 45 shapes the coherent light from the light source 40. The diffractive optical element 50 diffracts the coherent light shaped by the shaping optical system 45 and directs it toward the illuminated area 90. The projection surface 95 is illuminated in a pattern that corresponds to the diffraction characteristics of the diffractive optical element 50.

The projection surface 95 is not particularly limited. Examples of the projection surface 95 include a road, a sidewalk, a parking lot, a warehouse floor, a plaza, a playground, a park, a schoolyard, a field, a rough field, a building wall, a building ceiling, the surface of water, and the surface of the ocean. The projection surface 95 may be a flat surface, a curved surface, or a folded surface. In the example shown in FIG. 5, the projection surface 95 is a folded surface. For example, the road and a wall serve as the projection surface 95. In the example shown in FIG. 5, the road and the wall are perpendicular to each other. In the example shown in FIG. 5, the illuminated area 90 is located on the road and the wall.

The illuminated area 90 is linear. The illuminated area 90 may be linear, curved, or a combination of curved and linear, as shown in FIG. 2. The illuminated area 90 includes a distal end 90A and a proximal end 90B as the two ends of the line. The distal end 90A is the end farthest from the illumination device 30. The proximal end 90B is the end closer to the illumination device 30. That is, as shown in FIG. 2, when observed from the normal direction to the projection surface 95, the distance between the proximal end 90B and the illumination device 30 is shorter than the distance between the distal end 90A and the illumination device 30. When observed from the normal direction to the projection surface 95, the distance from the illumination device 30 to a position within the illuminated area 90 may increase as the position moves from the proximal end 90B to the distal end 90A along the longitudinal direction of the illuminated area 90. Furthermore, the lighting device 30 may face a position within the illuminated area 90 in the normal direction ND of the projection surface 95. As shown in FIG. 2, the lighting device 30 may face a position on an extension of the illuminated area 90 in the normal direction ND of the projection surface 95. An extension of the illuminated area 90 means a position or area that is shifted from the illuminated area 90 along the longitudinal direction of the illuminated area 90.

The angle Xa (see FIG. 3) between the direction of travel of the coherent light from the illumination device 30 toward the distal end 90A and the normal direction ND of the projection surface 95 is 60° or greater, and may be 70° or greater, 80° or greater, or 85° or greater. The angle Xb (see FIG. 3) between the direction of travel of the coherent light from the illumination device 30 toward the distal end 90A and the normal direction ND of the projection surface 95 is 20° or less, may be 10° or less, or may be 5° or less. Here, unless otherwise specified, the normal direction ND of the projection surface 95 refers to the normal direction of the projection surface 95 at the center position PC, which is the center of the distal end 90A and the proximal end 90B along the longitudinal direction of the illuminated area 90.

As shown in FIG. 4 , the angle Xb between the propagation direction of the coherent light from the illumination device 30 toward the distal end 90A and the normal direction ND of the projection surface 95 may be less than 0°, or may be less than -10°, or may be less than -20°. The angle Xa between the propagation direction of the coherent light from the illumination device 30 toward the distal end 90A and the normal direction ND of the projection surface 95 is a positive value. If the propagation direction of the coherent light from the illumination device 30 toward the proximal end 90B is inclined with respect to the normal direction ND of the projection surface 95 toward the same side as the propagation direction of the coherent light from the illumination device 30 toward the distal end 90A, the value of the angle Xb is a positive value. If the propagation direction of the coherent light from the illumination device 30 toward the proximal end 90B is inclined with respect to the normal direction ND of the projection surface 95 toward the opposite side to the propagation direction of the coherent light from the illumination device 30 toward the distal end 90A, the value of the angle Xb is a negative value.

In the illustrated example, the normal direction ND is parallel to the third direction D3. In the illustrated example, the illuminated area 90 extends in the first direction D1. That is, the longitudinal direction of the illuminated area 90 is parallel to the first direction D1.

Line illumination is achieved by irradiating the illuminated area 90 with coherent light. Line illumination can be used for a variety of purposes, including decoration. Line illumination can also be used as a guide. For example, line illumination can be used to indicate work routes, work locations, movement routes, and area boundaries. Line illumination can be used to indicate work routes, such as road and sidewalk construction, road and sidewalk maintenance, agricultural work, field maintenance, pesticide spraying, cleaning, snow removal, and line drawing. Line illumination can be used to indicate locations or areas where marking or surveying is being carried out, as work locations. Line illumination can be used to indicate, for example, the movement routes of work vehicles performing the above work, or the movement routes of people. Line illumination can be used to indicate, for example, the boundaries between passable areas and no-passable areas. Line illumination can be used to indicate areas where entry is prohibited or areas where entry is prohibited.

As described above, the illuminated area 90 illuminated with coherent light by the illumination device 30 is linear, with a distal end 90A far from the illumination device 30 and a proximal end 90B close to the illumination device 30 at both ends. The angle Xa between the direction of travel of the coherent light toward the distal end 90A and the normal direction ND of the projection surface 95 is 60° or greater. Therefore, illumination can be provided over a long distance from the illumination device 30. The angle between the direction of travel of the coherent light toward the proximal end 90B and the normal direction ND of the projection surface 95 is 20° or less. Therefore, illumination can be provided near the illumination device 30.

This line illumination can provide an appropriate guide that leads from a reference position 97 near the illumination device 30 to a target position 96 far away from the illumination device 30. Preferably, a guide connecting the reference position 97 and the target position 96 can be provided. For example, surveying and measurements can be efficiently performed from the reference position 97 to the target position 96. As another example, when work is being performed at the reference position 97, a work route can be provided to perform that work to the target position 96. More specifically, since the positional relationship between the reference position 97 and the target position 96 can be observed using the line illumination, surveying and marking can be performed easily and with high precision. Furthermore, when drawing a line from the reference position 97 to the target position 96, the line can be drawn easily, quickly, and with high precision. Furthermore, the line illumination connecting the reference position 97 and the target position 96 can be used to divide areas, for example, to indicate no-entry zones or off-limits areas.

In contrast, conventional technology has not been able to provide bright line illumination at a position far from the lighting device while also being able to bring the line illumination close enough to the lighting device. Line illumination as a guide was performed so that the illuminated area passed over a target position far from the lighting device. However, the illuminated area did not extend close to the lighting device. With this conventional technology, it was difficult to determine whether the reference position near the lighting device and the illuminated device had an appropriate positional relationship. Specifically, it was difficult to determine whether the reference position was located on an extension of the illuminated area. It was even more difficult to adjust the orientation of the illuminated area passing over the target position and the position of the reference position so that the reference position was located on an extension of the illuminated area. As a result, when conventional line illumination is used as a work guide, an inappropriate reference position can lead to problems such as an inappropriate work path from the reference position to the illuminated area. An inappropriate orientation of the illuminated area can lead to problems such as an inappropriate work path along the illuminated area.

In response to this problem, in this embodiment, angles Xa and Xb are adjusted as described above. Therefore, it is possible for the illuminated area 90, which passes through the distant target position 96, to extend close to the reference position 97, and even pass over the reference position 97. Therefore, this embodiment can address the problem of the conventional art. This embodiment allows for accurate guidance from the reference position 97 near the lighting device 30 to the distant target position 96 of the lighting device 30.

Furthermore, the radiation intensity (watts/steradian) from the lighting device 30 toward one position within the illuminated region 90 is smaller than the radiation intensity (watts/steradian) from the lighting device 30 toward another position located between that position and the distal end 90A. The diffractive optical element 50 included in the lighting device 30 makes it easy to adjust the distribution of radiation intensity from the lighting device 30 toward each position within the illuminated region 90. That is, the radiation intensity toward positions farther away from the lighting device 30 can be increased. In addition, the radiation intensity (watts/steradian) from the lighting device 30 toward an arbitrary position within the illuminated region 90 may be equal to or less than the radiation intensity (watts/steradian) from the lighting device 30 toward any other position located between that arbitrary position and the distal end 90A. That is, the radiation intensity may gradually increase as the distance from the lighting device 30 increases.

Also, as shown in FIG. 2, the illuminated area 90 is divided into five equal sections along its longitudinal direction, from the proximal end 90B to the distal end 90A, namely, the first section 90S1 to the fifth section 90S5. The radiant intensity (watts/steradian) in a direction from the lighting device 30 toward a position in the nth section, where n is an integer between 1 and 4, may be equal to or less than the radiant intensity (watts/steradian) in a direction from the lighting device 30 toward a position in the (n+1)th section. The average radiant intensity (watts/steradian) in a direction from the lighting device 30 toward a position in the nth section, where n is an integer between 1 and 4, may be equal to or less than the average radiant intensity (watts/steradian) in a direction from the lighting device 30 toward a position in the n+1th section. These radiant intensity distributions also show a tendency for the radiant intensity to increase with increasing distance from the lighting device 30. The average value of radiation intensity in a direction toward a position within each zone is determined by dividing the target zone into three zones in both the longitudinal direction of the illuminated area 90 and the direction perpendicular to the longitudinal direction, resulting in a total of nine zones, and the average value of radiation intensity in a direction toward one position within each zone is determined.

Adjusting the radiation intensity (watts/steradian) in this manner may reduce brightness in the area near the lighting device 30 within the illuminated area 90. However, a worker guided by the line illumination can use the line illumination to confirm the location of the distant target position 96 while performing work near the lighting device 30. Therefore, even if the radiation intensity toward a position near the lighting device 30 within the illuminated area 90 is low, the line illumination can be used to determine whether the target position 96 is appropriate near the lighting device 30. If the reference position 97 is not located within the illuminated area 90 or is not located on an extension of the illuminated area 90, the orientation of the illuminated area 90 and/or the position of the reference position 97 can be easily adjusted to position the reference position 97 within the illuminated area 90 or on an extension of the illuminated area 90. On the other hand, the radiation intensity toward the distant area from the lighting device 30 within the illuminated area 90 can be set high. In this way, by adjusting the radiation intensity distribution, the illuminated area 90 can be brightly illuminated near the target position 96, which is far from the lighting device 30.

The radiant intensity (Watts/steradian) is measured using an ADCMT power meter 8230. The radiant intensity can be determined by dividing the radiant flux (Watts) measured by this power meter by the solid angle (steradian). The solid angle is proportional to the effective area D (m ² ) of the sensor measuring the radiant flux and inversely proportional to the square of the measurement distance.

As a result, when providing line illumination from near the lighting device 30 to far away, the distant area can be brightly illuminated. In other words, the limited radiant flux (watts) of the lighting device can be effectively distributed to provide line illumination that acts as a guide from a position near the lighting device 30 to a position far away from the lighting device 30, while improving the visibility of the line illumination at a distance.

Figures 6 and 7 show the light distribution characteristics of the lighting device 30 in angular space. Angular space can be expressed in angular space coordinates. The angular space coordinates shown in Figures 6 and 7, as well as Figures 9, 11, and 12 (described later), have the origin O set to the direction of travel of the zeroth-order light. The vertical axis θV in the angular space coordinates represents the angle (°) of inclination vertically with respect to the direction of travel of the zeroth-order light. The horizontal axis θH in the angular space coordinates represents the angle (°) of inclination horizontally with respect to the direction of travel of the zeroth-order light. In Figures 6, 7, 9, 11, and 12, the distribution area DA of the coherent light emitted from the exit end or diffractive surface of the lighting device 30 is shown in angular space coordinates. The distribution area DA is the illuminated area in angular space coordinates. The distribution area DA represents the diffuse angular distribution in angular space coordinates.

6 and 7, when illuminating a linear illumination area 90, the angular range of the distribution area DA along the vertical axis θV in the angular space coordinate system may be greater than the angular range of the distribution area DA along the horizontal axis θH in the angular space coordinate system. In other words, the angular range of diffusion of the coherent light in the vertical direction may be greater than the angular range of diffusion of the coherent light in the horizontal direction. In the angular space coordinate system shown in FIGS. 6 and 7, the scale of the angle (°) on the vertical axis is the same as the scale of the angle (°) on the vertical axis. Therefore, the length of the distribution area DA along the vertical axis θV in the illustrated angular space coordinate system may be longer than the length of the distribution area DA along the horizontal axis θH in the angular space coordinate system. By appropriately adjusting the distribution area DA in angular space in this way, a linear illumination area 90 extending from the vicinity of the lighting device 30 to a distance can be illuminated.

In the example shown in FIG. 6, the distribution area DA in the angular space coordinate system has a trapezoidal shape. The trapezoidal shape includes an upper base and a lower base parallel to the horizontal axis θH. The length along the horizontal axis θH of the upper base located above the vertical axis θV, in other words, on the side with a large positive value, is smaller than the length along the horizontal axis θH of the lower base. In other words, the width of the trapezoidal shape along the horizontal axis θH is narrower above the vertical axis θV than below the vertical axis θV. In the distribution area DA shown in FIG. 6, the width along the horizontal axis θH of the trapezoidal shape gradually increases from above the vertical axis θV to below it. With an illumination device 30 having such light distribution characteristics, the width of the illuminated area 90 on the projection surface 95 along the second direction D2 can be made constant, as shown in FIG. 2.

In the example shown in Figure 7, the distribution area DA on the angular space coordinate system has a rectangular shape. With an illumination device 30 that achieves the light distribution characteristics shown in Figure 7, as shown in Figure 8, the width of the illuminated area 90 on the projection surface 95 along the second direction D2 increases with increasing distance from the illumination device 30 in the first direction. With this example, distant areas of the illuminated area 90 illuminated by the illumination device 30 can be clearly observed from near the illumination device 30.

The coherent light diffracted by the diffractive optical element 50 includes not only first-order diffracted light but also multi-order diffracted light such as second-order diffracted light and third-order diffracted light. The coherent light diffracted by the diffractive optical element 50 also includes negative-order diffracted light. Typically, the gradation of the relief hologram is set to 3 or more, for example, to increase the diffraction efficiency of first-order diffracted light. The first-order diffracted light may be used primarily to illuminate the illuminated region 90. The first-order diffracted light may be incident on only a portion of the illuminated region 90. The first-order diffracted light may be incident on the entire illuminated region 90. The first-order diffracted light may be incident on only the entire illuminated region 90.

The angular range along the vertical axis θV of the first-order light distribution region DA1 in the angular space coordinate system of first-order diffracted light diffracted by the diffractive optical element 50 may be wider than the angular range along the horizontal axis θH of the first-order light distribution region DA1. The first-order light distribution region DA1 in the angular space coordinate system may be rectangular. The first-order light distribution region DA1 in the angular space coordinate system may be trapezoidal, with the width along the horizontal axis θH being narrower above the vertical axis θV than below the vertical axis θV. By adjusting the first-order light distribution region DA1 in angular space, the linear illuminated region 90 can be brightly illuminated with first-order diffracted light with high diffraction efficiency.

The radiation intensity of first-order diffracted light in a direction from the illumination device 30 toward one position within the illuminated region 90 may be greater than the radiation intensity of first-order diffracted light in a direction from the illumination device 30 toward another position located between that position and the proximal end 90B. Additionally, the radiation intensity of first-order diffracted light in a direction from the illumination device 30 toward an arbitrary position within the illuminated region 90 may be greater than or equal to the radiation intensity of first-order diffracted light in a direction from the illumination device 30 toward any other position located between that arbitrary position and the proximal end 90B. With such a radiation intensity distribution of first-order diffracted light, the first-order diffracted light, which is diffracted with high efficiency, is directed toward a position within the illuminated region 90 that is far from the illumination device 30. Therefore, by adjusting the radiation intensity distribution of the first-order diffracted light, it is possible to brightly illuminate the illuminated region 90 in areas far from the illumination device 30, such as areas near the target position 96.

By dividing the illuminated area 90 into five equal parts along its longitudinal length, the illuminated area 90 is divided into five sections, a first section 90S1 through a fifth section 90S5, from the proximal end 90B to the distal end 90A. (n) is an integer between 1 and 4, and the radiant intensity (watts/steradian) of the first-order diffracted light in a direction from the lighting device 30 toward a position within the (n+1)th section may be equal to or greater than the radiant intensity (watts/steradian) of the first-order diffracted light in a direction from the lighting device 30 toward a position within the (n+1)th section. (n) is an integer between 1 and 4, and the average radiant intensity (watts/steradian) of the first-order diffracted light in a direction from the lighting device 30 toward a position within the (n+1)th section may be equal to or greater than the average radiant intensity (watts/steradian) of the first-order diffracted light in a direction from the lighting device 30 toward a position within the (n+1)th section. The average value of the radiation intensity of first-order diffracted light in a direction toward a position within each zone is determined by dividing the target zone into three zones in both the longitudinal direction of the illuminated region 90 and the direction perpendicular to the longitudinal direction, resulting in a total of nine zones, and specifying the average value of the radiation intensity of first-order diffracted light in a direction toward one position within each zone. By adjusting the radiation intensity distribution of the first-order diffracted light in this way, it is possible to brightly illuminate the illuminated region 90 in areas far from the illumination device 30, for example, in the vicinity of the target position 96.

Diffraction light of orders other than first order may be used to illuminate the illuminated region 90, in addition to or instead of first order diffracted light. In this example, as shown in FIGS. 2, 3, and 5, the illumination device 30 may face a position on an extension of the illuminated region 90 from the normal direction ND. The illumination device 30 may face a position within the illuminated region 90 from the normal direction ND. Depending on the relative positions of the illumination device 30 and the illuminated region 90, diffracted light of orders other than first order can be used to illuminate an additional region that is shifted in the longitudinal direction of the linear first partial region 91 illuminated by first order diffracted light. In other words, the linear first partial region 91 illuminated by first order diffracted light and the additional region illuminated using diffracted light of orders other than first order are aligned in the longitudinal direction of the illuminated region 90. The additional region can also be connected to the linear first partial region 91. Therefore, by effectively utilizing diffracted light of orders other than the first to illuminate the illuminated area 90, it is possible to achieve line illumination that is longer than line illumination using only first-order diffracted light. This makes effective use of the limited radiant flux (watts) of the lighting device 30, allowing the long illuminated area 90 to be brightly illuminated even from a distance.

In an example where diffracted light of an order other than the first order is used in the illuminated area 90, the first-order light distribution area DA1, which indicates the distribution area of the first-order diffracted light on the above-mentioned angular space coordinates, may include the origin O.

Furthermore, the origin O included in the primary light distribution area DA1 on the angular space coordinate system may be located at the center position HC along the horizontal axis θH of the primary light distribution area DA1 at the position where the origin O is located on the vertical axis θV, as shown in FIG. 9. In other words, the center position HC on the horizontal axis θH of the primary light distribution area DA1 may be located at the origin O of the angular space coordinate system.

On the angular space coordinate system, the distribution region of diffracted light of orders other than the first order (positive) is a range that includes the first order light distribution region DA1. As shown in Figure 9, on the angular space coordinate system, the -1st order light distribution region DA01 of -1st order diffracted light is a region that is point-symmetric with the first order light distribution region DA1, with the origin O as the center. On the angular space coordinate system, the distribution region of diffracted light of orders other than the -1st order (negative) is a region that includes the -1st order light distribution region DA01.

Therefore, by adjusting the position of the first-order light distribution area DA1 in the angular space coordinates as described above, it is possible to use diffracted light of orders other than the first order to illuminate an additional area 93 that is shifted along the longitudinal direction of the first partial area 91 relative to the linear first partial area 91 illuminated by the first-order diffracted light. That is, as shown in FIG. 10 , the linear first partial area 91 illuminated by first-order diffracted light and the additional area 93 illuminated by diffracted light of orders other than the first order are aligned along the longitudinal direction of the illuminated area 90. It is also possible to connect the additional area 93 to the linear first partial area 91. Therefore, by effectively utilizing diffracted light of orders other than the first order to illuminate the illuminated area 90, it is possible to achieve line illumination that is longer than line illumination using only first-order diffracted light. Furthermore, the diffraction efficiency of the diffractive optical element 50 decreases as the diffraction angle range of the first-order diffracted light increases. Therefore, by illuminating the illumination area 90 using negative-order diffracted light in addition to first-order diffracted light, the diffraction angle range of the first-order diffracted light can be narrowed, improving the diffraction efficiency of the diffractive optical element 50. This makes effective use of the limited radiant flux (watts) of the illumination device 30, allowing the long illumination area 90 to be brightly illuminated even from a distance.

When the radiation intensity caused by first-order diffracted light increases in the direction away from the lighting device 30, the illuminated area 90 can be brightly illuminated at a distance. At this time, the radiation intensity caused by positive orders of diffracted light other than the first order also increases in the direction away from the lighting device 30. On the other hand, the radiation intensity caused by negative order diffracted light increases in the direction away from the first distal end 91A. In other words, by using negative order diffracted light in addition to first order diffracted light to illuminate the illuminated area 90, the entire illuminated area 90 can be brightly illuminated.

As shown in FIG. 11 , the center position HC along the horizontal axis θH of the primary light distribution area DA1 in the angular space coordinate system may be shifted somewhat along the horizontal axis θH from the origin O of the angular space coordinate system. For example, the center position HC may be shifted along the horizontal axis θH from the origin O of the angular space coordinate system by an amount equal to or less than 20% of the width HW along the horizontal axis θH of the primary light distribution area DA1 at the position corresponding to the origin O on the vertical axis θV. Even in this example, the linear first partial area 91 illuminated by first-order diffracted light and the additional area 93 illuminated using diffracted light of orders other than the first are aligned generally in the longitudinal direction of the illuminated area 90. This achieves the same effect as when the center position HC is located on the origin O.

12, the origin O of the primary light distribution region DA1 in the angular space coordinate system may be located lower than a position that is 2/5 of the length VL of the primary light distribution region DA1 along the vertical axis from the upper edge DA1U of the primary light distribution region DA1. In other words, the origin O of the primary light distribution region DA1 in the angular space coordinate system may be located between a position that is 2/5 of the length VL of the primary light distribution region DA1 along the vertical axis from the upper edge DA1U of the primary light distribution region DA1 and the lower edge DA1L of the primary light distribution region DA1. By adjusting the position of the primary light distribution region DA1 in the angular space coordinate system in this manner, it is possible to use negative-order diffracted light to illuminate an additional region 93 that is shifted in the longitudinal direction of the linear first partial region 91 illuminated by the first-order diffracted light. The additional region 93 is connected to the first partial region 91 from the illumination device side (proximal end side). In other words, by using -1st-order diffracted light or other negative-order diffracted light, it is possible to achieve line illumination longer than line illumination using only first-order diffracted light. Therefore, the limited radiant flux (watts) of the illumination device 30 can be effectively utilized to brightly illuminate the long illuminated region 90 even at a distance. Note that illumination using -1st-order diffracted light or negative-order diffracted light tends to be darker than illumination using first-order diffracted light. However, the region 93 illuminated by the -1st-order diffracted light or negative-order diffracted light is near the illumination device 30. Therefore, even if the illumination is not sufficiently bright, the reference position 97 can be easily aligned with the additional region 93 of the illuminated region 90.

In the example shown in FIG. 12, the origin O of the primary light distribution region DA1 in the angular space coordinate system is offset downward along the vertical axis from the upper edge DA1U of the primary light distribution region DA1 by a distance equal to or greater than two-fifths of the length VL of the primary light distribution region DA1 along the vertical axis. In this example, the origin O of the angular space coordinate system is located above the center position VC of the primary light distribution region DA1 on the vertical axis θV. In the angular space coordinate system, the -1st order light distribution region DA01 is point-symmetric with the primary light distribution region DA1, with respect to the origin O. Therefore, as shown in FIG. 13, the position of the region 93 illuminated by -1st order diffracted light is offset toward the distal end 90A from the position of the first partial region 91 illuminated by the 1st order diffracted light. However, the -2nd order light distribution region DA02 is an area obtained by doubling the -1st order light distribution region DA01 along the vertical axis θV and along the horizontal axis θH in the angular space coordinate system. For this reason, as shown in Figure 13, the region 94 illuminated by -2nd-order diffracted light includes a first partial region 91 illuminated by first-order diffracted light, and further extends significantly from the first partial region 91 toward the proximal end 90B along the first direction D1. As a result, in the example shown in Figures 12 and 13, the region 94 illuminated by a negative order diffracted light other than the -1st order, for example, -2nd-order diffracted light, can include a second partial region 92 that is connected to the first partial region 91 illuminated by first-order diffracted light and is on the illumination device side (proximal end 90B side) of the first partial region 91.

As shown in FIG. 9 , the origin O of the primary light distribution region DA1 in the angular space coordinate system may be located below the center position VC of the primary light distribution region DA1 on the vertical axis θV. By adjusting the position of the primary light distribution region DA1 in the angular space coordinate system in this manner, negative-order diffracted light, such as -1st-order diffracted light, can be used to illuminate additional regions 93 and 94 that are shifted in the longitudinal direction of the linear first partial region 91 illuminated by the first-order diffracted light. At least a portion of the additional regions 93 and 94 is located closer to the proximal end 90B in the longitudinal direction of the illuminated region 90 than the first partial region 91 illuminated by the first-order diffracted light. Furthermore, the diffraction efficiency of -1st-order diffracted light generally tends to be higher than the diffraction efficiency of other negative-order diffracted light. Therefore, by illuminating the additional regions 93 and 94 to a certain degree, the reference position 97 can be easily aligned with the additional regions 93 and 94 of the illuminated region 90.

By utilizing diffracted light of orders other than first-order diffracted light as described above, the illuminated area 90 can include a linear first partial area 91 onto which the first-order diffracted light diffracted by the diffractive optical element 50 is incident, and a second partial area 92 connected to the first partial area 91 from the proximal end. This second partial area 92 is connected to the first partial area 91 from the illumination device side (proximal end). The second partial area 92 may also be linear. According to this example, by using diffracted light of orders other than first-order, which may not be used effectively, it is possible to achieve line illumination that is longer than line illumination using only first-order diffracted light. Therefore, the limited radiant flux (watts) of the illumination device 30 can be effectively utilized to brightly illuminate a long illuminated area even from a distance.

Note that illumination using diffracted light of orders other than the first order tends to be darker than illumination using first order diffracted light. However, the second partial area 92 illuminated by diffracted light of orders other than the first order is located near the lighting device 30. This makes it easy to align the reference position 97 with the second partial area 92 of the illuminated area 90, even if the illumination is not sufficiently bright.

Therefore, the radiation intensity (watts/steradian) in the direction from the lighting device 30 toward a position within the second partial region 92 may be less than the radiation intensity (watts/steradian) in the direction from the lighting device 30 toward a position within the first partial region 91. The radiation intensity (watts/steradian) in the direction from the lighting device 30 toward a position within the second partial region 92 may be less than the radiation intensity (watts/steradian) in the direction from the lighting device 30 toward an arbitrary position within the first partial region 91. The radiation intensity (watts/steradian) in the direction from the lighting device 30 toward an arbitrary position within the second partial region 92 may be less than the radiation intensity (watts/steradian) in the direction from the lighting device 30 toward an arbitrary position within the first partial region 91.

As shown in Figures 10 and 13, the first partial region 91 may be a linear region extending in the longitudinal direction of the illuminated region 90. The illustrated first partial region 91 includes a first distal end 91A and a first proximal end 91B as both ends of the line. The first distal end 91A is the end closest to the distal end 90A in the longitudinal direction of the illuminated region 90. The first proximal end 91B is the end farthest from the proximal end 90B in the longitudinal direction of the illuminated region 90.

As described above, the use of the diffractive optical element 50 makes it possible to easily adjust the distribution of radiation intensity (watts/steradian) from the lighting device 30 toward each position within the illuminated region 90. The radiation intensity (watts/steradian) from the lighting device 30 toward one position within the first partial region 91 may be smaller than the radiation intensity from the lighting device 30 toward another position within the first partial region 91 located between the one position and the first distal end 91A. That is, the radiation intensity toward a position farther away from the lighting device 30 within the first partial region 91 may be set higher. Furthermore, the radiation intensity from the lighting device 30 toward an arbitrary position within the first partial region 91 may be equal to or less than the radiation intensity from the lighting device 30 toward any other position within the first partial region 91 located between the arbitrary position and the first distal end 91A within the first partial region 91. That is, the radiation intensity may gradually increase as the distance from the lighting device 30 increases toward the position farther away from the lighting device 30 within the first partial region 91.

Also, as shown in FIG. 10 , by dividing the first partial region 91 into five equal parts along its longitudinal length, the first partial region 91 is divided into five sections, from the first proximal end 91B to the first distal end 91A, from the first proximal end 91B to the first distal end 91A, namely, the first partial region 91S1 to the fifth partial region 91S5. Where k is an integer between 1 and 4, the radiant intensity (watts/steradian) in a direction from the lighting device 30 toward a position in the kth partial region may be equal to or less than the radiant intensity (watts/steradian) in a direction from the lighting device 30 toward a position in the k+1th partial region. Where k is an integer between 1 and 4, the average radiant intensity (watts/steradian) in a direction from the lighting device 30 toward a position in the kth partial region may be equal to or less than the average radiant intensity (watts/steradian) in a direction from the lighting device 30 toward a position in the k+1th partial region. The average value of radiation intensity in a direction toward a position within each partial area is determined as the average value of radiation intensity in a direction toward one position within each partial area by dividing the target partial area into three in each of the longitudinal directions of the illuminated area 90 and the directions perpendicular to the longitudinal directions, resulting in a total of nine partial areas.

By adjusting the radiation intensity in this way, it is possible to illuminate the first partial area 91 with a brightness distribution that appears generally uniform when observed from a position near the lighting device 30, such as the reference position 97.

In the example shown in Figures 3 to 5, the lighting device 30 is attached to a support member 85 such as a tripod. The lighting device 30 is held in a fixed position relative to the projection surface 95 and the illuminated area 90 by the support member 85. When the relative positional relationship between the lighting device 30 and the projection surface 95 is fixed, coherent light is projected onto the illuminated area 90 on the projection surface 95, which is in a predetermined positional relationship with the lighting device 30. For example, when the projection surface 95 is flat, a pattern in the shape of the illuminated area 90 is projected onto the area of the projection surface 95, which is in a predetermined positional relationship with the mobile body 10 with the lighting device. The support member 85 may support the lighting device 30 so that the orientation and position can be adjusted.

As shown in FIG. 14, the lighting device 30 may be attached to a mobile body 15. The mobile body 15 is a mobile device. Examples of mobile bodies include automobiles, ships, and airplanes. In the example shown in FIG. 14, the mobile body 15 and the lighting device 30 constitute a mobile body 10 with a lighting device. The mobile body 15 may move by being pushed or pulled by an operator. The mobile body 15 may include a movement assist device. The movement assist device outputs an assist force when the mobile body 15 moves by being pushed or pulled by the operator, thereby assisting the movement of the mobile body 15. The mobile body 15 may be movable along a straight line, and may also be movable along a curved or bent line. The movement direction of the mobile body 15 may be adjusted by operation by an operator riding on or pushing the mobile body 15, or by remote control by the operator.

As shown in FIG. 14, the mobile body 15 may be a work vehicle 20. The work vehicle 20 performs or assists in a specific task. The work vehicle 20 can move on the projection surface 95. Work can be performed while the work vehicle 20 is moving on the projection surface 95. The mobile body 15 and the work vehicle 20 may include wheels 22. The work vehicle 20 may include crawlers, caterpillars, etc. instead of or in addition to the wheels 22. The work vehicle 20 may include a drive unit 23.

Examples of work vehicles 20 include vehicles used to build roads and sidewalks, vehicles used to maintain roads and sidewalks, vehicles used for agricultural work, and vehicles used to maintain fields. Examples of road building and road maintenance vehicles include graders, asphalt finishers, road rollers, tire rollers, wheel loaders, mixer trucks, line pullers, snowplows, and sweepers. Examples of agricultural work vehicles and vehicles used to maintain fields include rice transplanters, harvesters, lawn mowers, tractors, chemical sprayers, and tillers. Other examples of work vehicles 20 include specialized vehicles and industrial vehicles specified in ISO 5053-1.

The work vehicle 20 shown in FIG. 14 includes a vehicle body 21, wheels 22 rotatably held on the vehicle body 21, and a handle 24 attached to the vehicle body 21. The work vehicle 20 also includes a drive unit 23 and a working device 25 supported on the vehicle body 21. The illustrated work vehicle 20 rotates the wheels 22 using driving force from the drive unit 23 to move or assist the movement of the work vehicle 20. The operator can adjust the orientation of the work vehicle 20 by applying force via the handle 24. In other words, the direction of movement of the work vehicle 20 is adjusted by the force applied by the operator to the handle 24.

14, the work vehicle 20 is a line-drawing vehicle that supplies ink, lime powder, etc. to the projection surface 95. The illustrated work vehicle 20 can be used to draw white or orange lines on roads, sidewalks, and parking lots. The illustrated work vehicle 20 can also be used to draw lines of various colors on the floors of gymnasiums and auditoriums. The work device 25 includes a colorant holding unit 26 that stores colorant, and a supply unit 27 that supplies the colorant from the colorant holding unit 26 to the projection surface 95. The supply unit 27 is a tubular member. The supply unit 27 has a supply port 27a that opens downward. The supply port 27a faces the projection surface 95 on which the work vehicle 20 is positioned. As the work vehicle 20 moves, the work device 25 supplies colorant to the projection surface 95. This allows lines 99 to be drawn on the projection surface 95 while the work vehicle 20 is moving.

The lighting device 30 is attached to the work vehicle 20. The lighting device 30 irradiates the illuminated area 90 on the projection surface 95 with coherent light. In other words, the lighting device 30 projects a pattern of the illuminated area 90 onto the projection surface 95. In the illustrated example, the projection surface 95 is formed by the road surface. When the relative positional relationship between the lighting device 30 and the projection surface 95 is constant, the coherent light is initially projected onto the illuminated area 90 on the projection surface 95, which is in a predetermined positional relationship with the mobile body 10 with the lighting device. For example, when the projection surface 95 is flat, a pattern in the shape of the illuminated area 90 is projected onto the area of the projection surface 95 that is in a predetermined positional relationship with the mobile body 10 with the lighting device. Then, as the mobile body 10 with the lighting device moves on the projection surface 95, the illuminated area 90 also moves on the projection surface 95.

As described above, the illuminated area 90 illuminated with coherent light by the illumination device 30 is linear, with a distal end 90A far from the illumination device 30 and a proximal end 90B close to the illumination device 30. Line illumination by the illumination device 30 can provide an appropriate guide leading from a reference position 97 near the illumination device 30 to a target position 96 far from the illumination device 30. Preferably, a guide connecting the reference position 97 and the target position 96 can be provided.

The illuminated area 90 can indicate the path the work vehicle 20 will take if it continues moving forward while maintaining its current direction of travel. Therefore, while the work vehicle 20 is moving and performing work, the operator can adjust the orientation of the work vehicle 20 based on the illuminated area 90. Specifically, the operator can adjust the orientation of the work vehicle 20 so that the illuminated area 90 is located on the target position 96. Alternatively, the operator can adjust the orientation of the work vehicle 20 so that the target position 96 is located on an extension of the illuminated area 90, which extends along a straight line. Additionally, the operator can easily confirm that the current work position is located on the illuminated area 90 or on an extension of the illuminated area 90. When work is being performed at the reference position 97, a work route can be provided for completing the work to the target position 96. In other words, the operator can move the lighting-equipped mobile body 10 toward the target position 96 and also confirm that the current work position is appropriate.

As shown in FIG. 14, the illuminated area 90 may at least partially include the area WA where work is being performed by the work vehicle 20. In the illustrated example, the illuminated area 90 includes the area on the projection surface 95 facing the supply port 27a of the work device 25, i.e., the area where the colorant is applied. Therefore, it is possible to confirm that the work position 98 where the line 99 is drawn is located on the illuminated area 90. According to this example, the orientation and position of the work vehicle 20 can be easily and accurately adjusted with respect to the area to be worked. It is also easy to confirm whether work using the work vehicle 20 is actually being performed in the area to be worked. In the illustrated example, it is easy and accurate to determine whether the colorant has been applied to the area to be applied. This allows the line to be drawn from the reference position 97 to the target position 96 easily, quickly, and with high accuracy.

As shown in Figures 15A to 15D, a target 80 may be used in combination with the lighting device 30. The target 80, together with the lighting device 30, constitutes the work support device 5. The target 80 is used to make it easier to observe the target position 96. As shown in Figures 15A to 15D, the target 80 may be placed on the target position 96. This makes it easier for the operator to observe the target position 96 through the target 80. The operator can then align the illuminated area 90 with the target position 96 by positioning the illuminated area 90 relative to the target 80.

In the example shown in FIG. 15A, the target 80 is made of a resin cone. In the example shown in FIG. 15B, the target 80 has a rectangular parallelepiped shape. The target 80 has a display unit 81. The operator can align the illuminated area 90 with the target 80 while observing the display unit 81. The display unit 81 may also emit light. In the example shown in FIG. 15C, the target 80 has a light-emitting unit 82 extending in a third direction D3 perpendicular to the projection surface 95. As shown in FIG. 15D, the target 80 may have a reflecting unit 83. The reflecting unit 83 may diffusely reflect coherent light from the lighting device 30. The reflecting unit 83 may retroreflect coherent light from the lighting device 30. In the example shown in FIG. 15D, coherent light is incident on only a portion of the reflecting unit 83. When working at night, the target 80 has a light-emitting portion 82, which makes it much easier to adjust the direction of movement of the lighting-equipped mobile body 10. In addition, the reflecting portion 83 of the target 80 reflects the coherent light from the lighting device 30, which also makes it much easier to adjust the direction of movement of the lighting-equipped mobile body 10 when working at night.

The target 80 may be portable. That is, the target 80 may be portable by the operator without using any special means. For example, the target 80 may be kept on the work vehicle 20. When the work location using the work vehicle 20 is changed, the target 80 may be placed on the next target position 96.

As shown in FIG. 15D, the width of the target 80 along the second direction D2 may be smaller than the width of the illuminated region 90 along the second direction D2. According to this example, the illuminated region 90 also extends behind the target 80, as shown in FIG. 15D. Therefore, the illuminated region 90 can be easily positioned relative to the target 80 and the target position 96. For similar reasons, the target 80 may be transparent or may have a hole to the extent that the illuminated region 90 extends behind the target 80.

The target 80 is not limited to the example shown. The target 80 is not limited to a member that protrudes or bulges from the projection surface 95 in the third direction D3. The target 80 may be, for example, a marker or line provided on the projection surface 95. In the example of the line-drawing cart shown in the figure, a line drawn in a previous operation, i.e., a line that is fading, could be the target 80. Furthermore, plants such as trees, or objects installed on the projection surface 95 could also be the target 80.

The length L (see Figure 2) of the illuminated area 90 on the projection surface 95 may be 3 m or more, 5 m or more, 20 m or more, or even 50 m or more. The length L of the illuminated area 90 is the length along the longitudinal direction of the illuminated area 90. By setting the illuminated area 90 to 3 m or more, the illuminated area 90 can serve as an effective guide when aiming at a distant target position 96. The length L (m) of the illuminated area 90 may be 100 m or less, in combination with the lower limit mentioned above.

The width W (see Figure 2) of the illuminated area 90 on the projection surface 95 may be 0.002 m or more and 0.2 m or less, 0.01 m or more and 0.2 m or less, 0.02 m or more and 0.1 m or less, or 0.03 m or more and 0.05 m or less. The width W of the illuminated area 90 is the length of the illuminated area 90 perpendicular to the longitudinal direction of the illuminated area 90. By setting a lower limit for the width W of the illuminated area 90, a long illuminated area 90 can be adequately observed. By setting an upper limit for the width W of the illuminated area 90, the radiant flux emitted from the lighting device 30 is concentrated on the illuminated area 90 with a limited width W, allowing the illuminated area 90 to be brightly illuminated.

The ratio (L/W) of the length L (m) of the illuminated area 90 to the width W (m) of the illuminated area 90 may be set to 25 or greater and 10,000 or less, or 50 or greater and 1,000 or less, or 100 or greater and 500 or less. With an illuminated area 90 in which a lower limit is set for the ratio of the length L to the width W, the limited radiant flux emitted from the lighting device 30 can be effectively utilized to brightly illuminate the long illuminated area 90 over a long distance.

Next, the specific configuration of the lighting device 30 will be described.

As shown in FIG. 1, the illumination device 30 includes a light source 40 that emits coherent light, a shaping optical system 45 that shapes the coherent light from the light source 40, and a diffractive optical element 50 that diffracts the coherent light shaped by the shaping optical system 45 and directs it toward an illuminated area 90. The illumination device 30 illuminates the illuminated area 90 with the coherent light diffracted by the diffractive optical element 50. This illumination device 30 can illuminate a large illuminated area 90 on a projection surface 95 or an illuminated area 90 that extends far away from the illumination device 30. In other words, the illumination device 30 using the light source 40 and the diffractive optical element 50 can achieve the above-described length L (m), width W (m), and ratio of length L (m) to width W (m) for the illuminated area 90.

The light source 40 emits coherent light with a constant wavelength and phase. The coherent light emitted from the light source 40 has excellent linearity. Therefore, the light source 40 is suitable for use in an illumination device 30 that illuminates a distant object. Various types of light sources can be used as the light source 40. A laser light source that emits laser light may also be used as the light source 40. An example of a laser light source is a semiconductor laser light source. In the example shown in FIG. 1, the light source 40 includes a single coherent light source. Therefore, in the example shown in FIG. 1, the illuminated area 90 is illuminated with coherent light of a color corresponding to the wavelength range of the coherent light emitted from the light source 40.

The shaping optical system 45 shapes the light emitted from the light source 40. For example, the shaping optical system 45 shapes the shape of the coherent light in a cross section perpendicular to the optical axis or the three-dimensional shape of the coherent light. The shaping optical system 45 may also expand the cross-sectional area of the coherent light in a cross section perpendicular to the optical axis of the coherent light.

In the example shown in FIG. 1, the shaping optical system 45 shapes the light emitted from the light source 40 into a widened, parallel beam. In other words, the shaping optical system 45 functions as a collimating optical system. In the example shown in FIG. 1, the shaping optical system 45 has a first lens 46 and a second lens 47 arranged along the optical path. The first lens 46 shapes the light emitted from the light source 40 into a diverging beam. The second lens 47 shapes the diverging beam generated by the first lens 46 into a parallel beam. In this example, the second lens 47 functions as a collimating lens.

The diffractive optical element 50 changes the direction of travel of coherent light from the light source 40. The coherent light diffracted by the diffractive optical element 50 illuminates the illuminated area 90 on the projection surface 95. The diffractive optical element 50 diffracts the coherent light from the light source 40 and directs it toward the illuminated area 90 on the projection surface 95. As a result, the light diffracted by the diffractive optical element 50 is projected onto the projection surface 95. The projection surface 95 is illuminated with the pattern of the illuminated area 90 that corresponds to the diffraction pattern of the diffractive optical element 50.

The diffractive optical element 50 may be a hologram element. Using a hologram element as the diffractive optical element 50 makes it easier to design the diffraction characteristics of the diffractive optical element 50. It is relatively easy to design a hologram element that can project light only over the entire desired area on the projection surface 95, which has a predetermined position, contour shape, size, and orientation. The area on the projection surface 95 that is irradiated with coherent light becomes the illuminated area 90.

When designing the diffractive optical element 50, the illuminated area 90 is set in real space at a predetermined position relative to the diffractive optical element 50, with a predetermined contour shape, size, and orientation. The position, contour shape, size, and orientation of the illuminated area 90 on the projection surface 95 depend on the diffraction characteristics of the diffractive optical element 50. By adjusting the diffraction characteristics of the diffractive optical element 50, the position, contour shape, size, and orientation of the illuminated area 90 on the projection surface 95 can be adjusted as desired. Therefore, when designing the diffractive optical element 50, the position, contour shape, size, and orientation of the illuminated area 90 on the projection surface 95 are first determined. Next, the diffraction characteristics of the diffractive optical element 50 may be adjusted so that light can be projected over the entire illuminated area 90 that has been determined.

The diffractive optical element 50 can be fabricated as a computer-generated hologram (CGH). A computer-generated hologram is created by calculating a structure with desired diffraction characteristics on a computer. Therefore, using a computer-generated hologram as the diffractive optical element 50 eliminates the need to generate object light and reference light using a light source or optical system, or to record interference fringes on a hologram recording material by exposure. The illumination device 30 is designed to irradiate an illuminated area 90 with coherent light at a predetermined position relative to the illumination device 30 and with a predetermined contour shape, size, and orientation. By inputting information about the illuminated area 90 as parameters into a computer, a structure with diffraction characteristics capable of projecting diffracted light onto the illuminated area 90, such as an uneven surface, can be specified by computer calculation. By forming the specified structure, for example, by resin molding, the diffractive optical element 50 as a computer-generated hologram can be fabricated easily and at low cost.

The diffractive optical element 50 may be designed using, for example, the iterative Fourier transform method. When using the iterative Fourier transform method, processing may be performed assuming that the illuminated region 90 is located far from the diffractive optical element 50, and the pattern projected onto the projection surface 95 may be a Fraunhofer diffraction image. Therefore, the projection surface 95 may be non-parallel to the diffractive surface of the diffractive optical element 50.

As shown in FIG. 16, the diffractive optical element 50 may include multiple partial diffractive optical elements 55. Each partial diffractive optical element 55 may be, for example, a hologram element and may be configured similarly to the diffractive optical element 50 described above. In the example shown in FIG. 16, the coherent light diffracted by the multiple partial diffractive optical elements 55 is irradiated onto the same illuminated region 90. In other words, the light diffracted by each partial diffractive optical element 55 is irradiated onto the entire illuminated region 90 on the projection surface 95. With this type of diffractive optical element 50, light directed toward each position within the illuminated region 90 can be dispersed and emitted from the multiple partial diffractive optical elements 55 included in the diffractive optical element 50. This prevents each position on the diffractive optical element 50 from becoming too bright, improving laser safety.

Each partial diffractive optical element 55 may be configured to have the same diffraction characteristics. However, to achieve more accurate projection, each partial diffractive optical element 55 may be given diffraction characteristics that are individually designed depending on the placement position of that partial diffractive optical element 55 within the diffractive optical element 50. In this example, the diffraction characteristics of each partial diffractive optical element 55 are adjusted depending on differences in placement relative to the other partial diffractive optical elements 55, making it possible to precisely direct diffracted light only over the entire illuminated area 90 on the projection surface 95.

Furthermore, to obtain the above-described radiation intensity distribution, the partial diffractive optical elements 55 may have different diffraction characteristics. Each partial diffractive optical element 55 may direct coherent light toward a different portion of the illuminated area.

An illumination device 30 having a light source 40 that emits coherent light and a diffractive optical element 50 that diffracts the coherent light can illuminate a large illuminated area 90 on a projection surface 95 or an illuminated area 90 that extends to a position far away from the illumination device 30. In this case, the incident angle α of the coherent light at each position within the illuminated area 90 varies greatly. Here, the incident angle α at the illuminated area 90 refers to the angle that the traveling direction of the coherent light makes with the normal direction ND of the illuminated area 90.

In this lighting device 30, the diffractive optical element 50 adjusts the optical path of the coherent light. The optical path adjustment function of the diffractive optical element 50 is highly accurate. Therefore, the diffractive optical element 50 can adjust the optical path of the coherent light toward the illuminated area 90 of the desired shape. As a result, the illuminated area 90 can be set without being strongly restricted in its relative position with the lighting device 30, even in a position far away from the lighting device 30 or where the incident angle α of the coherent light becomes large. In other words, the degree of freedom in setting the illuminated area 90 and the projection surface 95 can be greatly improved. As a result, coherent light can be irradiated onto the illuminated area 90 with high precision.

As an example, a diffractive optical element 50 made of a computer-generated hologram can adjust the direction of travel of coherent light incident from a certain direction in angular space with an accuracy of ±0.01°. By using such a diffractive optical element 50, it is possible to illuminate an illuminated area 90 located at a distance of 1 m or more and 120 m or less from the diffractive optical element 50 with high precision. The edges of the illuminated area 90 can be made clear, allowing the operator to clearly observe areas located farther away from the illuminated area 90.

Figure 17 shows a specific configuration example of the lighting device 30. The lighting device 30 shown in Figure 17 is portable. That is, the lighting device 30 shown in Figure 17 can be carried by an operator without using any special means. The lighting device 30 has a casing 70. In the lighting device 30 shown in Figure 17, the light source 40, the shaping optical system 45, and the diffractive optical element 50 are fixed to the casing 70. In normal use, the light source 40, the shaping optical system 45, and the diffractive optical element 50 are not intended to be removed from the casing 70. The light source 40, the shaping optical system 45, and the diffractive optical element 50 cannot be removed from the casing 70. This maintains the relative positions of the light source 40, the shaping optical system 45, and the diffractive optical element 50. As a result, the illuminated area 90 on the projection surface 95, which is in a predetermined relative positional relationship with the lighting device 30, can be stably illuminated with high precision. It also prevents the light source 40, shaping optical system 45, and diffractive optical element 50 from shifting from their predetermined positions, improving laser safety.

17, the shaping optical system 45 includes a first lens 46, a second lens 47, and a third lens 48. The casing 70 includes a cylindrical portion 71 that holds the light source 40 and the shaping optical system 45, and a lid portion 72 fixed to the cylindrical portion 71. The cylindrical portion 71 is cylindrical with one end closed. The light source 40 is fixed to the closed end of the cylindrical portion 71. The inner dimension of the cylindrical portion 71 changes via a stepped portion 71a. The inner diameter increases from the upstream side to the downstream side along the optical path of the coherent light emitted from the light source 40. The first lens 46 and the second lens 47 are attached to each of the two stepped portions 71a. A spacing ring 73 that can control the distance between the lenses with high precision is provided within the cylindrical portion 71. The spacing ring 73 is disposed between the first lens 46 and the second lens 47. The spacing ring 73 is disposed between the second lens 47 and the third lens 48. A spacing ring 73 is disposed between the lid portion 72 and the third lens 48. The spacing ring 73 prevents the lenses from shifting relative to one another due to vibrations or shocks transmitted to the lighting device 30. The spacing ring 73 may be an annular or cylindrical member, for example. The spacing ring 73 may be made of a metal such as aluminum, or a resin. The resin may contain an inorganic material such as glass fiber to reduce the thermal expansion coefficient.

In order to maintain a constant relative position of the light source 40, shaping optical system 45, diffractive optical element 50, etc., the light source 40, shaping optical system 45, and diffractive optical element 50 may be fixed to the casing 70 using adhesive in combination with fixing by fitting.

For example, spacers may be used to fine-tune the relative positions of the light source 40, shaping optical system 45, and diffractive optical element 50. Thin metal plates may be used as spacers. Spacers may also be used in conjunction with the spacing ring 73 and adhesive.

Component parts such as the light source 40, shaping optical system 45, and diffractive optical element 50 may be held by a position adjustment holder that allows for fine adjustment of their position. The position adjustment holder may allow for fine adjustment of the position of the component by operating an adjustment part such as a screw. The component parts may be fixed to the casing 70 via the position adjustment holder. When using a position adjustment holder, the adjustment part such as a screw may be fixed with an adhesive or the like after the position of the component has been adjusted. The position adjustment holder may also be used in conjunction with the spacing ring 73 described above or other members for maintaining the relative positions of the finely adjusted components.

The casing 70 may be made non-disassemblyable, so that the relative positions of components such as the light source 40, shaping optical system 45, and diffractive optical element 50 are maintained. For example, the relative positions of components positioned by the manufacturer of the lighting device 30 may be maintained. For example, adhesive may be applied to the screw-fastened portions and fitting portions of the casing 70, making the casing 70 non-disassemblyable.

In the example shown in FIG. 17, the lighting device 30 includes a battery 74, a circuit 75, and a switch 76. The battery 74 may be a primary battery or a rechargeable secondary battery. The circuit 75 is electrically connected to the battery 74 and the switch 76. When the switch 76 is operated, the circuit 75 switches between supplying power from the battery 74 to the light source 40 and stopping the power supply.

The lighting device 30 may be powered by an external power source. For example, the casing may be provided with a connector for electrically connecting to an external power source. In this example, the lighting device 30 may include a primary battery or a secondary battery, or it may not include a primary battery or a secondary battery. A lighting device 30 that does not include a primary battery or a secondary battery is lightweight and therefore has excellent resistance to vibration and impact.

The lighting device 30 and casing 70 may be waterproof. To make the lighting device 30 waterproof, waterproof materials such as rubber or packing may be provided at the joints and fittings of the casing 70.

The lighting device 30 may have a temperature adjustment mechanism. The temperature adjustment mechanism may maintain the light source 40 and the circuit 75 at a temperature within a predetermined range. The temperature adjustment mechanism may heat or cool the light source 40 and the circuit 75. The temperature adjustment mechanism may be installed inside the casing 70. Examples of the temperature adjustment mechanism include a fan, heater, and cooler. The temperature adjustment mechanism may also use an electric heating wire, Peltier element, etc.

As shown in FIG. 18, the lighting device 30 may have multiple lighting fixtures 35. In the example shown in FIG. 18, each lighting fixture 35 may have the same configuration as the lighting device 30 described with reference to FIGS. 15 and 16. In the example shown in FIG. 18, the multiple lighting fixtures 35 may include light sources 40 that emit coherent light of different wavelengths. That is, in the example shown in FIG. 18, the lighting device 30 has multiple light sources 40 and multiple diffractive optical elements 50 corresponding to each light source 40. The coherent light emitted from each lighting fixture 35 overlaps in the illuminated area 90 on the projection surface 95, thereby illuminating the illuminated area 90 with the desired color. The lighting device 30 shown in FIG. 18 includes first to third lighting fixtures 35A to 35C. Each lighting fixture 35A to 35C has a light source 40A to 40C, a shaping optical system 45A to 45C, and a diffractive optical element 50A to 50C.

In the example shown in FIG. 18, multiple lighting fixtures 35 may each include a light source 40 that emits light of the same wavelength. The coherent illumination light emitted from each lighting fixture 35 overlaps in the illuminated area 90 on the projection surface 95, thereby brightly illuminating the illuminated area 90.

In the example shown in FIG. 18, the multiple lighting devices 35A-35C are arranged in the third direction D3, which is the normal direction ND of the projection surface 95. The example shown in FIG. 18 is not limiting, and the multiple lighting devices 35A-35C may also be arranged, for example, in the second direction D2.

As shown in FIG. 19, the illumination device 30 may include a scanning device 60. The illumination device 30 shown in FIG. 19 includes multiple diffractive optical elements 50A-50C. The scanning device 60 adjusts the optical path of the coherent light emitted by the light source 40 to control whether or not coherent light is supplied to the diffractive optical element 50, and to control the distribution of the coherent light to the multiple diffractive optical elements 50A-50C. The scanning device 60 may be configured using various components that can change the optical path using refraction, reflection, diffraction, etc. Examples of various components that can change the optical path include lenses, prisms, mirrors, and diffractive optical elements.

The scanning device 60 changes the optical path of the coherent light from the light source 40 over time. As a result, the incident position of the coherent light moves on the multiple diffractive optical elements 50A-50C. In other words, the diffractive optical element 50 onto which the coherent light from the light source 40 is incident changes among the multiple diffractive optical elements 50A-50C. The illustrated scanning device 60 has a reflective surface that can rotate around a single axis RA. An example of such a scanning device 60 is a galvanometer mirror.

The illuminated area 90 may be divided into multiple partial illuminated areas 901, 902, and 903 according to their positions in the first direction D1. Multiple diffractive optical elements 50A-50C may illuminate different partial illuminated areas 901, 902, and 903. This example narrows the diffraction angle range of light diffracted by a single diffractive optical element 50, thereby improving the diffraction efficiency of each diffractive optical element 50. Furthermore, by adjusting the amount of radiant flux directed toward the partial illuminated areas 901, 902, and 903, the radiant intensity distribution can be controlled with a high degree of freedom. Note that because the scanning device 60 operates at a speed that exceeds the resolution of human vision, it appears to a human as if all partial illuminated areas 901, 902, and 903 included in the illuminated area 90 are continuously illuminated simultaneously.

In the example shown in FIG. 20, the diffractive optical element 50 includes first to twelfth diffractive optical elements 50A to 50L. For example, the illuminated area 90 on the projection surface 95 is divided into first to twelfth partial illuminated areas 901 to 9012. The coherent light diffracted by the first to twelfth diffractive optical elements 50A to 50L is projected onto the respective first to twelfth partial illuminated areas 901 to 9012. The scanning device 60 directs light from the light source 40 to each of the diffractive optical elements 50A to 50L. The illumination device 30 can control whether or not to irradiate each of the diffractive optical elements 50A to 50L with light, depending on the operation of the scanning device 60. For example, the light source 40 switches between emitting and stopping light depending on the operation of the scanning device 60. As another example, a light-blocking member that blocks light enters and retracts from the optical path of light from the light source 40 depending on the operation of the scanning device 60. By controlling whether or not light is irradiated onto each diffractive optical element 50A-50L, coherent light can be projected onto only any one of the diffractive optical elements 50A-50L. This allows only any one of the first to twelfth partial illuminated areas 901-9012 to be illuminated, making it possible to illuminate the illuminated area 90 in the desired shape.

Note that the diffractive optical element 50 included in the illumination device 30 shown in Figures 18 to 20 may be divided into multiple partial diffractive optical elements 55.

In the embodiment described above, the illumination device 30 illuminates the illuminated area 90 on the projection surface 95. The illumination device 30 includes a light source 40 that emits coherent light, a shaping optical system 45 that shapes the coherent light from the light source 40, and a diffractive optical element 50 that diffracts the coherent light shaped by the shaping optical system 45 and directs it toward the illuminated area 90.

The illuminated area 90 is linear, including a distal end 90A far from the illumination device 30 and a proximal end 90B close to the illumination device 30. The angle between the direction of travel of the coherent light toward the distal end 90A and the normal direction ND of the projection surface 95 is 60° or greater. Therefore, illumination is possible over a long distance from the illumination device 30. The angle between the direction of travel of the coherent light toward the proximal end 90B and the normal direction ND of the projection surface 95 is 20° or less. Therefore, illumination is possible over the vicinity of the illumination device 30. This allows illumination of the linear illuminated area 90 connecting a target position 96 far from the illumination device 30 and a reference position 97 near the illumination device 30. This line illumination can provide appropriate guidance from the reference position 97 to the target position 96. Preferably, guidance can be provided connecting the reference position 97 and the target position 96.

For example, surveying and measurement from the reference position 97 to the target position 96 can be performed efficiently. It can also provide a work route for carrying out work being performed at the reference position 97 to the target position 96. Because the positional relationship between the reference position 97 and the target position 96 can be observed using line illumination, surveying and marking can be performed easily and with high precision. It can also be used to draw a line from the reference position 97 to the target position 96 easily and with high precision in a short amount of time.

Furthermore, the radiation intensity (watts/steradian) in the direction from the lighting device 30 toward one position within the illuminated area 90 is smaller than the radiation intensity (watts/steradian) in the direction from the lighting device 30 toward another position located between that position and the distal end 90A. Even if the radiation intensity (watts/steradian) is adjusted in this way, it is possible to determine whether the reference position 97 is appropriate near the lighting device 30 using line illumination. If the reference position 97 is not located within the illuminated area 90 or is not located on an extension of the illuminated area 90, the reference position 97 can be positioned within the illuminated area 90 or on an extension of the illuminated area 90 by adjusting at least one of the orientation of the illuminated area 90 and the position of the reference position 97. By adjusting the radiation intensity distribution, the illuminated area 90 can be brightly illuminated near a target position far from the lighting device 30.

As described above, according to this embodiment, when providing line illumination from the vicinity of the lighting device 30 to a distant location, the distant location can be brightly illuminated. In other words, the limited radiant flux (watts) of the lighting device 30 can be effectively distributed to provide line illumination that acts as a guide from a position near the lighting device 30 to a position far from the lighting device 30, while improving the visibility of the line illumination at a distance.

Although one embodiment has been described above with reference to specific examples, the embodiment is not limited to these specific examples. The above-described embodiment can be implemented with a variety of other specific examples, and various omissions, substitutions, modifications, additions, etc. can be made without departing from the spirit of the embodiment.

5: Work support device, 10: Mobile body with lighting device, 15: Mobile body, 20: Work vehicle, 30: Lighting device, 40: Light source, 45: Shaping optical system, 50: Diffractive optical element, 55: Partially diffractive optical element, 60: Scanning device, 80: Target, 85: Support member, 90: Illuminated area, 90A: Distal end, 90B: Proximal end, 91: First partial area, 91A: First distal end, 91B: Second 1 proximal end, 92: second partial area, 95: projection surface, 96: target position, 97: reference position, 98: working position, 99: line, DA: distribution area DA, DA1: primary light distribution area, DA1U: Upper edge, DA01: -1st order light distribution area, DA02: -2nd order light distribution area, VC: center position, HC: center position, D1: first direction, D2: second direction, D3: third direction, PC: center position

Claims (35)

An illumination device that illuminates an illumination area on a projection surface,
a light source that emits coherent light;
a shaping optical system that shapes the coherent light from the light source;
a diffractive optical element that diffracts the coherent light shaped by the shaping optical system and directs the light toward the illuminated area,
the illuminated area has a linear shape including a distal end far from the illumination device and a proximal end close to the illumination device;
an angle between a traveling direction of the coherent light from the illumination device toward the distal end and a normal direction of the projection surface is 60° or more;
an angle between a direction of travel of the coherent light from the illumination device toward the proximal end and the normal direction is 20° or less;
a radiation intensity in a direction from the lighting device toward one position in the illuminated area is smaller than a radiation intensity in a direction from the lighting device toward another position located between the one position and the distal end ;
Define an angular space coordinate system with the direction of travel of the zero-order light as the origin, the vertical angle as the vertical axis, and the horizontal angle as the horizontal axis,
a first-order light distribution area in the angular space coordinates of the first-order diffracted light diffracted by the diffractive optical element includes the origin,
the origin is located at a central position along the horizontal axis of the primary light distribution region at a position on the vertical axis that corresponds to the origin, or is shifted from the central position along the horizontal axis by a length that is 20% or less of a width along the horizontal axis of the primary light distribution region at a position on the vertical axis that corresponds to the origin . The lighting device of claim 1, wherein the radiation intensity in a direction from the lighting device toward any position within the illuminated area is equal to or less than the radiation intensity in a direction from the lighting device toward any other position located between the any position and the distal end. When the illuminated area is divided into five equal parts along its longitudinal direction, the illuminated area is divided into five sections, namely, a first section to a fifth section, from the proximal end to the distal end,
n is an integer from 1 to 4,
3. The lighting device according to claim 1, wherein the radiation intensity in a direction from the lighting device toward a position in the nth zone is equal to or less than the radiation intensity in a direction from the lighting device toward a position in the n+1th zone. The lighting device of claim 3, wherein the average radiation intensity in a direction from the lighting device toward a position within the nth zone is less than or equal to the average radiation intensity in a direction from the lighting device toward a position within the n+1th zone. An illumination device that illuminates an illumination area on a projection surface,
a light source that emits coherent light;
a shaping optical system that shapes the coherent light from the light source;
a diffractive optical element that diffracts the coherent light shaped by the shaping optical system and directs the light toward the illuminated area,
the illuminated area has a linear shape including a distal end far from the illumination device and a proximal end close to the illumination device;
an angle between a traveling direction of the coherent light from the illumination device toward the distal end and a normal direction of the projection surface is 60° or more;
an angle between a direction of travel of the coherent light from the illumination device toward the proximal end and the normal direction is 20° or less;
a radiation intensity in a direction from the lighting device toward one position in the illuminated area is smaller than a radiation intensity in a direction from the lighting device toward another position located between the one position and the distal end;
When the illuminated area is divided into five equal parts along its longitudinal direction, the illuminated area is divided into five sections, namely, a first section to a fifth section, from the proximal end to the distal end,
n is an integer from 1 to 4,
a radiation intensity in a direction from the lighting device toward a position in the n-th zone is equal to or less than a radiation intensity in a direction from the lighting device toward a position in the n+1-th zone;
An illumination device, wherein the average value of the radiation intensity in a direction from the illumination device toward a position in the nth zone is less than or equal to the average value of the radiation intensity in a direction from the illumination device toward a position in the n+1th zone. Define an angular space coordinate system with the direction of travel of the zero-order light as the origin, the vertical angle as the vertical axis, and the horizontal angle as the horizontal axis,
6. The lighting device according to claim 1 , wherein an angular range of the vertical axis of a distribution region in the angular space coordinates of the coherent light traveling from the lighting device toward the illuminated region is larger than an angular range of the horizontal axis of the distribution region. 7. The illumination device according to claim 6, wherein a first-order light distribution region in the angular space coordinates of the first -order diffracted light diffracted by the diffractive optical element has a rectangular shape or a trapezoidal shape in which a width along the horizontal axis is narrower above the vertical axis than below the vertical axis. 8. The illumination device according to claim 1, wherein a radiation intensity of first-order diffracted light diffracted by the diffractive optical element in a direction from the illumination device toward one position in the illuminated region is greater than a radiation intensity of the first-order diffracted light in a direction from the illumination device toward another position located between the one position and the proximal end . 9. The illumination device according to claim 8, wherein a radiation intensity of the first-order diffracted light in a direction from the illumination device toward an arbitrary position within the illuminated region is equal to or greater than a radiation intensity of the first-order diffracted light in a direction from the illumination device toward any other position located between the arbitrary position and the proximal end . When the illuminated area is divided into five equal parts along its longitudinal direction, the illuminated area is divided into five sections, namely, a first section to a fifth section, from the proximal end to the distal end,
n is an integer from 1 to 4,
10. The lighting device according to claim 8, wherein the radiation intensity of the first-order diffracted light in a direction from the lighting device toward a position within the (n+1)th zone is equal to or greater than the radiation intensity of the first-order diffracted light in a direction from the lighting device toward a position within the (n+ 1) th zone. An illumination device that illuminates an illumination area on a projection surface,
a light source that emits coherent light;
a shaping optical system that shapes the coherent light from the light source;
a diffractive optical element that diffracts the coherent light shaped by the shaping optical system and directs the light toward the illuminated area,
the illuminated area has a linear shape including a distal end far from the illumination device and a proximal end close to the illumination device;
an angle between a traveling direction of the coherent light from the illumination device toward the distal end and a normal direction of the projection surface is 60° or more;
an angle between a direction of travel of the coherent light from the illumination device toward the proximal end and the normal direction is 20° or less;
a radiation intensity in a direction from the lighting device toward one position in the illuminated area is smaller than a radiation intensity in a direction from the lighting device toward another position located between the one position and the distal end;
a radiation intensity of first-order diffracted light diffracted by the diffractive optical element in a direction from the illumination device toward one position in the illuminated area is greater than a radiation intensity of the first-order diffracted light in a direction from the illumination device toward another position located between the one position and the proximal end,
When the illuminated area is divided into five equal parts along its longitudinal direction, the illuminated area is divided into five sections, namely, a first section to a fifth section, from the proximal end to the distal end,
n is an integer from 1 to 4,
An illumination device, wherein the radiation intensity of the first-order diffracted light in a direction from the illumination device toward a position within an n+1th region is equal to or greater than the radiation intensity of the first-order diffracted light in a direction from the illumination device toward a position within an nth region. 12. The lighting device according to claim 10, wherein an average value of the radiation intensity of the first-order diffracted light in a direction from the lighting device toward a position in the n+1th zone is equal to or greater than an average value of the radiation intensity of the first-order diffracted light in a direction from the lighting device toward a position in the nth zone. The illumination device according to any one of claims 1 to 12 , wherein the illumination device is located within the illuminated area or on an extension of the illuminated area. Define an angular space coordinate system with the direction of travel of the zero-order light as the origin, the vertical angle as the vertical axis, and the horizontal angle as the horizontal axis,
a first-order light distribution area in the angular space coordinates of the first-order diffracted light diffracted by the diffractive optical element includes the origin,
12. The lighting device according to claim 5 or 11, wherein the origin is located at a center position along the horizontal axis of the primary light distribution region at a position on the vertical axis that corresponds to the origin, or is located at a position shifted from the center position along the horizontal axis by a length that is 20% or less of a width along the horizontal axis of the primary light distribution region at the position on the vertical axis that corresponds to the origin. Define an angular space coordinate system with the direction of travel of the zero-order light as the origin, the vertical angle as the vertical axis, and the horizontal angle as the horizontal axis,
a first-order light distribution area in the angular space coordinates of the first-order diffracted light diffracted by the diffractive optical element includes the origin,
15. The lighting device according to claim 1, wherein the origin is located below a position that is spaced downward along the vertical axis from an upper edge of the primary light distribution region by 2/5 of a length of the primary light distribution region along the vertical axis. An illumination device that illuminates an illumination area on a projection surface,
a light source that emits coherent light;
a shaping optical system that shapes the coherent light from the light source;
a diffractive optical element that diffracts the coherent light shaped by the shaping optical system and directs the light toward the illuminated area,
the illuminated area has a linear shape including a distal end far from the illumination device and a proximal end close to the illumination device;
an angle between a direction of travel of the coherent light from the illumination device toward the distal end and a normal direction of the projection surface is 60° or more;
an angle between a direction of travel of the coherent light from the illumination device toward the proximal end and the normal direction is 20° or less;
a radiation intensity in a direction from the lighting device toward one position in the illuminated area is smaller than a radiation intensity in a direction from the lighting device toward another position located between the one position and the distal end;
Define an angular space coordinate system with the direction of travel of the zero-order light as the origin, the vertical angle as the vertical axis, and the horizontal angle as the horizontal axis,
a first-order light distribution area in the angular space coordinates of the first-order diffracted light diffracted by the diffractive optical element includes the origin,
the origin is located below a position spaced downward along the vertical axis from an upper edge of the primary light distribution region by 2/5 of a length of the primary light distribution region along the vertical axis. Define an angular space coordinate system with the direction of travel of the zero-order light as the origin, the vertical angle as the vertical axis, and the horizontal angle as the horizontal axis,
a first-order light distribution area in the angular space coordinates of the first-order diffracted light diffracted by the diffractive optical element includes the origin,
The lighting device according to claim 1 , wherein the origin is located below a center position along the vertical axis of the primary light distribution region. An illumination device that illuminates an illuminated area on a projection surface,
a light source that emits coherent light;
a shaping optical system that shapes the coherent light from the light source;
a diffractive optical element that diffracts the coherent light shaped by the shaping optical system and directs the light toward the illuminated area,
the illuminated area has a linear shape including a distal end far from the illumination device and a proximal end close to the illumination device;
an angle between a traveling direction of the coherent light from the illumination device toward the distal end and a normal direction of the projection surface is 60° or more;
an angle between a direction of travel of the coherent light from the illumination device toward the proximal end and the normal direction is 20° or less;
a radiation intensity in a direction from the lighting device toward one position in the illuminated area is smaller than a radiation intensity in a direction from the lighting device toward another position located between the one position and the distal end;
Define an angular space coordinate system with the direction of travel of the zero-order light as the origin, the vertical angle as the vertical axis, and the horizontal angle as the horizontal axis,
a first-order light distribution area in the angular space coordinates of the first-order diffracted light diffracted by the diffractive optical element includes the origin,
The illumination device, wherein the origin is located below a center position along the vertical axis of the primary light distribution region. the illuminated region includes a linear first partial region onto which first-order diffracted light diffracted by the diffractive optical element is incident, and a second partial region connected to the first partial region from the proximal end side;
19. The lighting device according to claim 1, wherein a radiation intensity in a direction from the lighting device toward a position in the second partial region is smaller than a radiation intensity in a direction from the lighting device toward a position in the first partial region. An illumination device that illuminates an illuminated area on a projection surface,
a light source that emits coherent light;
a shaping optical system that shapes the coherent light from the light source;
a diffractive optical element that diffracts the coherent light shaped by the shaping optical system and directs the light toward the illuminated area,
the illuminated area has a linear shape including a distal end far from the illumination device and a proximal end close to the illumination device;
an angle between a traveling direction of the coherent light from the illumination device toward the distal end and a normal direction of the projection surface is 60° or more;
an angle between a direction of travel of the coherent light from the illumination device toward the proximal end and the normal direction is 20° or less;
a radiation intensity in a direction from the lighting device toward one position in the illuminated area is smaller than a radiation intensity in a direction from the lighting device toward another position located between the one position and the distal end;
the illuminated region includes a linear first partial region onto which first-order diffracted light diffracted by the diffractive optical element is incident, and a second partial region connected to the first partial region from the proximal end side;
An illumination device, wherein a radiation intensity in a direction from the illumination device towards a position in the second partial region is smaller than a radiation intensity in a direction from the illumination device towards a position in the first partial region. 21. The lighting device according to claim 19, wherein the radiation intensity in a direction from the lighting device toward the one position in the second partial region is equal to or less than the radiation intensity in a direction from the lighting device toward any position in the first partial region. 22. The lighting device according to claim 19, wherein the radiation intensity in a direction from the lighting device toward any position within the second partial region is equal to or less than the radiation intensity in a direction from the lighting device toward any position within the first partial region . 23. The lighting device according to claim 19, wherein an average radiation intensity in a direction from the lighting device toward any position within the second partial region is equal to or less than an average radiation intensity in a direction from the lighting device toward any position within the first partial region. the first subregion includes a first distal end remote from the lighting device and a first proximal end close to the lighting device;
24. The lighting device of claim 19, wherein the radiation intensity in a direction from the lighting device toward one position in the first partial region is smaller than the radiation intensity in a direction from the lighting device toward another position in the first partial region located between the one position and the first distal end. 25. The lighting device of claim 24, wherein the radiation intensity in a direction from the lighting device toward any position within the first partial region is less than or equal to the radiation intensity in a direction from the lighting device toward any other position within the first partial region located between the any position and the first distal end . When the first partial region is divided into five equal parts along its longitudinal direction, the first partial region is divided into five sections from the first proximal end to the first distal end, from the first partial section to the fifth partial section,
k is an integer from 1 to 4,
26. The lighting device of claim 24 or 25, wherein the radiation intensity in a direction from the lighting device toward a position in the kth partial area is less than or equal to the radiation intensity in a direction from the lighting device toward a position in the k+1th partial area. 27. The lighting device of claim 26, wherein the average value of the radiation intensity in a direction from the lighting device toward a position within the kth sub-area is less than or equal to the average value of the radiation intensity in a direction from the lighting device toward a position within the k+ 1th sub-area. A lighting device according to any one of claims 1 to 27 ;
A moving body equipped with an illumination device, comprising: a moving body on which the illumination device is mounted. A lighting device according to any one of claims 1 to 27 ;
a target disposed within the illuminated area. 1. A lighting method for illuminating an illumination area on a projection surface using a lighting device, comprising:
illuminating a linear illumination area including a distal end far from the illumination device and a proximal end close to the illumination device;
the illumination device includes a diffractive optical element that diffracts coherent light and directs it toward the illuminated area;
an angle between a traveling direction of the coherent light from the illumination device toward the distal end and a normal direction of the projection surface is 60° or more;
an angle between a direction of travel of the coherent light from the illumination device toward the proximal end and the normal direction is 20° or less;
a radiation intensity in a direction from the lighting device toward one position in the illuminated area is smaller than a radiation intensity in a direction from the lighting device toward another position located between the one position and the distal end ;
Define an angular space coordinate system with the direction of travel of the zero-order light as the origin, the vertical angle as the vertical axis, and the horizontal angle as the horizontal axis,
a first-order light distribution area in the angular space coordinates of the first-order diffracted light diffracted by the diffractive optical element includes the origin,
the origin is located at a central position along the horizontal axis of the primary light distribution region at a position on the vertical axis that corresponds to the origin, or is located at a position shifted from the central position along the horizontal axis by a length that is 20% or less of a width along the horizontal axis of the primary light distribution region at a position on the vertical axis that corresponds to the origin . 1. A lighting method for illuminating an illumination area on a projection surface using a lighting device, comprising:
illuminating a linear illumination area including a distal end far from the illumination device and a proximal end close to the illumination device;
the illumination device includes a diffractive optical element that diffracts coherent light and directs it toward the illuminated area;
an angle between a traveling direction of the coherent light from the illumination device toward the distal end and a normal direction of the projection surface is 60° or more;
an angle between a direction of travel of the coherent light from the illumination device toward the proximal end and the normal direction is 20° or less;
a radiation intensity in a direction from the lighting device toward one position in the illuminated area is smaller than a radiation intensity in a direction from the lighting device toward another position located between the one position and the distal end ;
When the illuminated area is divided into five equal parts along its longitudinal direction, the illuminated area is divided into five areas, namely, a first area to a fifth area, from the proximal end to the distal end,
n is an integer from 1 to 4,
a radiation intensity in a direction from the lighting device toward a position in the nth zone is equal to or less than a radiation intensity in a direction from the lighting device toward a position in the n+1th zone;
An illumination method , wherein an average value of radiation intensity in a direction from the illumination device toward a position in the nth zone is less than or equal to an average value of radiation intensity in a direction from the illumination device toward a position in the n+1th zone . 1. A lighting method for illuminating an illumination area on a projection surface using a lighting device, comprising:
illuminating a linear illumination area including a distal end far from the illumination device and a proximal end close to the illumination device;
the illumination device includes a diffractive optical element that diffracts coherent light and directs it toward the illuminated area;
an angle between a traveling direction of the coherent light from the illumination device toward the distal end and a normal direction of the projection surface is 60° or more;
an angle between a direction of travel of the coherent light from the illumination device toward the proximal end and the normal direction is 20° or less;
a radiation intensity in a direction from the lighting device toward one position in the illuminated area is smaller than a radiation intensity in a direction from the lighting device toward another position located between the one position and the distal end ;
a radiation intensity of first-order diffracted light diffracted by the diffractive optical element in a direction from the illumination device toward one position in the illuminated area is greater than a radiation intensity of the first-order diffracted light in a direction from the illumination device toward another position located between the one position and the proximal end,
When the illuminated area is divided into five equal parts along its longitudinal direction, the illuminated area is divided into five areas, namely, a first area to a fifth area, from the proximal end to the distal end,
n is an integer from 1 to 4,
an illumination method, wherein the radiation intensity of the first-order diffracted light in a direction from the illumination device toward a position within an n+1th region is equal to or greater than the radiation intensity of the first-order diffracted light in a direction from the illumination device toward a position within an nth region . 1. A lighting method for illuminating an illumination area on a projection surface using a lighting device, comprising:
illuminating a linear illumination area including a distal end far from the illumination device and a proximal end close to the illumination device;
the illumination device includes a diffractive optical element that diffracts coherent light and directs it toward the illuminated area;
an angle between a traveling direction of the coherent light from the illumination device toward the distal end and a normal direction of the projection surface is 60° or more;
an angle between a direction of travel of the coherent light from the illumination device toward the proximal end and the normal direction is 20° or less;
a radiation intensity in a direction from the lighting device toward one position in the illuminated area is smaller than a radiation intensity in a direction from the lighting device toward another position located between the one position and the distal end ;
Define an angular space coordinate system with the direction of travel of the zero-order light as the origin, the vertical angle as the vertical axis, and the horizontal angle as the horizontal axis,
a first-order light distribution area in the angular space coordinates of the first-order diffracted light diffracted by the diffractive optical element includes the origin,
the origin is located below a position spaced downward along the vertical axis from an upper edge of the primary light distribution region by 2/5 of a length of the primary light distribution region along the vertical axis . 1. A lighting method for illuminating an illumination area on a projection surface using a lighting device, comprising:
illuminating a linear illumination area including a distal end far from the illumination device and a proximal end close to the illumination device;
the illumination device includes a diffractive optical element that diffracts coherent light and directs it toward the illuminated area;
an angle between a traveling direction of the coherent light from the illumination device toward the distal end and a normal direction of the projection surface is 60° or more;
an angle between a direction of travel of the coherent light from the illumination device toward the proximal end and the normal direction is 20° or less;
a radiation intensity in a direction from the lighting device toward one position in the illuminated area is smaller than a radiation intensity in a direction from the lighting device toward another position located between the one position and the distal end ;
Define an angular space coordinate system with the direction of travel of the zero-order light as the origin, the vertical angle as the vertical axis, and the horizontal angle as the horizontal axis,
a first-order light distribution area in the angular space coordinates of the first-order diffracted light diffracted by the diffractive optical element includes the origin,
The illumination method , wherein the origin is located below a center position along the vertical axis of the primary light distribution region . 1. A lighting method for illuminating an illumination area on a projection surface using a lighting device, comprising:
illuminating a linear illumination area including a distal end far from the illumination device and a proximal end close to the illumination device;
the illumination device includes a diffractive optical element that diffracts coherent light and directs it toward the illuminated area;
an angle between a traveling direction of the coherent light from the illumination device toward the distal end and a normal direction of the projection surface is 60° or more;
an angle between a direction of travel of the coherent light from the illumination device toward the proximal end and the normal direction is 20° or less;
a radiation intensity in a direction from the lighting device toward one position in the illuminated area is smaller than a radiation intensity in a direction from the lighting device toward another position located between the one position and the distal end ;
the illuminated region includes a linear first partial region onto which first-order diffracted light diffracted by the diffractive optical element is incident, and a second partial region connected to the first partial region from the proximal end side;
A lighting method , wherein a radiation intensity in a direction from the lighting device towards a position in the second partial region is smaller than a radiation intensity in a direction from the lighting device towards a position in the first partial region .