JP7615148B2 - Image Projection Device - Google Patents

Description

The present invention relates to an image projection device for a vehicle that projects a predetermined image onto a road surface.

Conventionally, there is known a technology for vehicle lighting that projects an image on a road surface to attract the attention of surrounding vehicles and pedestrians and to assist the driver in driving. For example, Patent Document 1 proposes an invention of a departure notification display device that uses light to draw a departure notification display of a predetermined shape on the road surface in the vehicle's traveling direction, allowing pedestrians to accurately grasp the timing when the vehicle will start.

JP 2020-55519 A

However, when projecting an image using an image projection device for a vehicle, the illuminance (brightness) of the image decreases as the projection position moves away from the vehicle, and the image appears darker. For this reason, for example, when multiple images are projected using multiple light sources with the same luminous flux, there is a problem that the brightness of the projected images varies.

SUMMARY OF THE PRESENT DISCLOSURE It is therefore a first object of the present invention to provide an image projection device capable of suppressing variations in brightness of a plurality of images projected using a plurality of light sources.

In addition, vehicles are equipped with various vehicle lighting devices such as headlights, backup lamps, turn signal lamps, etc. In addition, these vehicle lighting devices also have functions such as displaying the driving status of the vehicle to surrounding vehicles and pedestrians and calling their attention. For this reason, there has been a demand for a system that can coordinate vehicle lighting devices with image projection devices to provide more appropriate displays to the outside of the vehicle.

Therefore, a second object of the present invention is to provide an image projection device that can perform more appropriate display toward the outside of the vehicle in coordination with other vehicle lamps.

Furthermore, when an image is projected onto the road surface using an image projection device, light is projected diagonally from above toward the road surface, so the width increases the further away from the vehicle body, and the desired image cannot be displayed.

Therefore, a third object of the present invention is to provide an image projection device which can project an image in a well-balanced shape both in the portion close to the vehicle body and in the portion far from the vehicle body.

In order to solve the above first problem, the image projection device of the present invention is an image projection device for a vehicle, comprising a plurality of light sources and a plurality of lenses respectively facing the plurality of light sources, the plurality of lenses each having a different diameter, and a lens with a larger diameter projects an image at a position farther away from the image projection device than a lens with a smaller diameter.

In this case, it is preferable that the plurality of light sources are provided so as to emit light of the same luminous flux, and the plurality of lenses are provided with respective diameters so as to project images of the same illuminance.

The plurality of lenses may be arranged such that the optical axis of light passing through at least one lens is non-parallel to the optical axis of light passing through the other lenses.

The lens may be attached in an inclined position toward the side of the vehicle.

A configuration may be adopted in which a plurality of light sources are arranged side by side on the left and right, and light emitted from the plurality of light sources projects an image that extends obliquely to the side of the vehicle.

A configuration may also be adopted in which a plurality of light sources are arranged vertically in parallel, and light emitted from the plurality of light sources projects an image extending in the vehicle length direction.

It is also possible to place the larger diameter lens below the smaller diameter lens.

It is also possible to provide the image projection device near other vehicle lamps so that the light emitted from the light source is visually recognized as a single unit together with the light emitted from the other vehicle lamps.

In order to solve the second problem described above, the image projection device of the present invention is an image projection device for a vehicle capable of projecting multiple images onto a road surface at one time, and is equipped with multiple light sources that each emit light to project the multiple images, and a control means for controlling the light sources, and is characterized in that the control means turns the light sources on and off in conjunction with the turning on and off of other vehicle lamps.

The control means is also capable of turning on a plurality of light sources sequentially.

Other vehicle lighting devices may include backup lamps and turn signal lamps.

The image projection device of the present invention is provided in parallel with other vehicle lamps, and the light emitted from the light source is visually recognized as one unit with the light emitted from the other vehicle lamps.

It is also possible to provide a configuration in which multiple light sources are arranged vertically in a row and an image extending in the vehicle length direction is projected using light emitted from the multiple light sources.

The light source and the image drawn by the light from the light source may be arranged on a straight line in a plan view.

It is also preferable to place the light source on the underside of the bumper.

In order to solve the third problem, the image projection device of the present invention is an image projection device for a vehicle, comprising a plurality of light sources, a plurality of lenses each facing the plurality of light sources, and a plate-shaped shade interposed between the light sources and the lenses, wherein the shade has a plurality of openings that allow light from the plurality of light sources to pass through respectively toward the plurality of lenses, and the openings are arranged in a trapezoidal shape.

The openings are preferably trapezoidal in shape, with the bottom base shorter than the top base, and are arranged in series.

It is also possible to provide three or more openings in the shade and arrange the openings at different distances from one another.

The multiple openings may be provided with different sizes.

According to the image projection device of the present invention, a lens with a larger diameter is configured to project an image at a position farther from the image projection device than a lens with a smaller diameter, and the illuminance of the image is increased as the image moves away from the image projection device, thereby achieving the effect of suppressing variations in brightness of the projected image.

In addition, according to the image projection device of the present invention, since it is controlled to light up in conjunction with other vehicle lamps, it has the effect of being able to more clearly convey messages displayed by the vehicle lamps to the outside of the vehicle.

Furthermore, according to the image projection device of the present invention, a shade is interposed between the light source and the lens, and an opening is provided in the shade to allow light from the light source to pass through, and the opening is trapezoidal in shape.Therefore, by adjusting the lengths of the upper and lower bases of the trapezoid, it is possible to project an image in a well-balanced shape with a simple configuration, both for areas close to the vehicle body and areas far from the vehicle body.

1 is a schematic diagram of an image projection device according to a first embodiment of the present invention. FIG. 2 is a schematic exploded perspective view of the image projection device of FIG. 1 . 2 is a schematic diagram showing a positional relationship between the image projection device of FIG. 1 and an obstacle, and a light distribution state. FIG. 2 is a schematic diagram showing a state in which the image projection device of FIG. 1 is provided in parallel with a backup lamp; 2 is a schematic diagram showing an image projected by the image projection device of FIG. 1; 13 is a schematic diagram showing a state in which an image projection device according to a modified example is provided in a lamp chamber of a headlamp. FIG. 7A is a schematic cross-sectional view of the lens portion taken along line AA of the image projection device shown in FIG. 6, and FIG. 7B is a schematic view showing the inclination state of the lens. 7 is a schematic diagram showing an image projected by the image projection device of FIG. 6. FIG. 11 is a schematic diagram of an image projection device according to a second embodiment of the present invention. FIG. 2 is a schematic exploded perspective view of the image projection device. 2 is a schematic diagram showing a state in which an image is projected onto a road surface by an image projection device; FIG. FIG. 2 is a schematic diagram showing an arrangement state of an image projection device. 1 is a schematic diagram showing an image projected by an image projection device provided in parallel with a backup lamp; 1A and 1B are schematic diagrams illustrating an image projected by an image projection device for a side turn signal lamp and a headlight, respectively. FIG. 11 is a schematic diagram of an image projection device according to a third embodiment of the present invention. FIG. 16 is a schematic exploded perspective view of the image projection device of FIG. 15. 16A and 16B are schematic diagrams showing an optical axis, a light beam, and a projected image by the image projection device of FIG. 15, in which FIG. 1A is a schematic cross-sectional view taken along line AA when the focal point is located within the lens, and FIG. 1B is a schematic view of the shade as viewed from the front of the device. 19A is a schematic diagram showing an image projected through a rectangular opening, and FIG. 19B is a schematic diagram showing an image projected through a trapezoidal opening in the case of FIG. 18. 1A is a schematic cross-sectional view taken along line AA when a focal point is not located within the lens, and FIG. 1B is a schematic view of the shade as viewed from the front of the device. 21A is a schematic diagram showing an image projected through a rectangular opening, and FIG. 21B is a schematic diagram showing an image projected through a trapezoidal opening in the case of FIG. 20. 16 is a schematic plan view showing the image projection device and the projected image of FIG. 15. 13 is a schematic diagram showing a state in which an image projection device according to a modified example is provided in a lamp chamber of a headlamp. FIG. 24A is a schematic cross-sectional view of the lens portion taken along line BB, and FIG. 24B is a schematic side view of the inclination of each lens, showing the arrangement and orientation of lenses in the image projection device of FIG. 23. 24A is a schematic diagram of the shade of the image projection device of FIG. 23 as viewed from the front of the device, and FIG. 24B is an enlarged view of an opening portion. 24 is a schematic plan view showing the image projection device and the projected image of FIG. 23.

Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. The image projection device 1 shown in Figs. 1 and 2 includes a plurality of light sources 2 (2c, 2b, 2a) that emit light L (Lc, Lb, Lc()) to project an image G (Gc, Gb, Ga), and a plurality of lenses 4 (4c, 4b, 4a) that face the light sources 2, respectively.

As shown in Figure 2, the image projection device 1 is composed of a board 7 on which a light source 2 is mounted, an attachment 5 for attaching a shade 3 to the board 7, the shade 3 that cuts the light L from the light source 2 into a shape corresponding to an image G, a lens 4 that transmits the light L from the light source 2, and an extension 6 that shields the internal structure of the image projection device 1 from the outside of the vehicle.

The light sources 2c, 2b, and 2c are LEDs having the same luminous flux, i.e., LEDs having the same current value and the same brightness, and are arranged vertically. Arranging the light sources 2 vertically has the advantage of simplifying the optical design of the lens compared to when they are arranged horizontally.

The light sources 2 are arranged so that the light beams Lc, Lb, and Lc emitted from the light sources 2c, 2b, and 2c descend at an incline toward the road surface. By arranging the light sources 2 in this manner, images Gc, Gb, and Gc extending in the vehicle length direction can be projected onto the road surface.

Furthermore, the light source 2 is arranged on the same straight line as the image G drawn by the light L from the light source 2 (see Figs. 5 and 8). By arranging the light source 2 and the image G on a straight line A, it becomes easier to understand that the images belong to the same function, compared to a case in which the light source 2 and the image G are projected with deviations to the left and right. In this case, a vehicle lamp (e.g., a backup lamp 52) arranged in parallel with the light source 2 may also be configured to be arranged on the same straight line as the light source 2 and the image G.

The shade 3 is provided with a trapezoidal opening 31 having an upper base 32 that is longer than a lower base 33. By appropriately adjusting the ratio between the upper base 32 and the lower base 33, it is possible to adjust the shape of the projected image G. For example, it is possible to provide the opening 31 in a rectangular shape and project a trapezoidal image G that becomes wider as it gets farther away from the vehicle body 51.

In the shade 3 of Example 1, the openings 31 are all provided with the same shape and area. By providing the openings 31 with the same area and shape, the structure of the shade 3 can be simplified and the manufacturing cost can be reduced.

The multiple lenses 4 (4c, 4b, 4a) are formed integrally and configured to pass multiple light beams Lc, Lb, Lc (from the multiple light sources 2c, 2b, 2c). The lenses 4c, 4b, 4a each have a different radius r (radius rc<radius rb<radius ra), and are provided so that the radius r increases toward the bottom. In this case, the lenses 4c, 4b, 4a are arranged so that the distance between the lenses 4 increases as the radius r increases so that the lenses do not overlap each other. The position of the lenses 4 from the light source 2 is determined according to their own focal length.

The lens 2 having a larger diameter r is provided so as to project the image G at a position farther from the vehicle body 51 than the lens 2 having a smaller diameter r. For example, the lens 4b has a larger diameter r than the lens 4c (diameter rb>diameter rc), and the image Gb projected by the lens 4b is drawn at a position farther from the vehicle body 51 than the image Gc projected by the lens 4c. Since the light flux passing through the lens 4b having a larger diameter r is greater than the light flux passing through the lens 4c having a smaller diameter r, the image Gb that is farther from the vehicle body 51 can be projected with the same illuminance as the image Gc that is closer to the vehicle body 51.

The lenses 4 are provided so that the optical axes of the lights Lc, Lb, and Lc passing through the lenses 4c, 4b, and 4a are non-parallel to each other. The optical axes of the lights Lc, Lb, and Lc intersect in a side view, and the images Gc, Gb, and Ga are projected in a direction from near the vehicle body 51 to farther away from the light source 2c arranged at the top, the light source 2b arranged in the middle, and the light source 2a arranged at the bottom in that order. At this time, the inclination of the lenses 4 is provided so that the closer the lens 4 is to project near the vehicle projection device 1 or the vehicle body 51, the greater the inclination. By providing the lenses 4 in this way, it is possible to project the images Gc, Gb, and Ga while avoiding obstacles such as the bumper 53, as shown in FIG. 3(a). On the other hand, if there is no obstacle between the image projection device 1 and the road surface that blocks the light L, it is also possible to select the order of the lenses 4a, 4b, and 4c from the top to the bottom as shown in FIG. 3(b).

4, the image projection device 1 is provided in parallel with the backup lamp 52 so that the emitted light L from the light source 2 is visually recognized as an integrated unit together with the light L' from the backup lamp 52. In particular, it is desirable that the distance d between the light source 2 and the light source 2' of the backup lamp 52 is 75 mm or less so that the emitted lights L, L' are visually recognized as an integrated unit.

5 shows a state in which the image projection device 1 having the above-mentioned configuration is turned on. The images Gc, Gb, and Ga are drawn on a straight line A obtained by projecting the optical axis of the light L emitted from the light source 2 onto the road surface. In the image G, the image Ga projected at a position farther from the vehicle body 51 extends longer in the vehicle length direction than the image Gc projected at a position closer to the vehicle body 51 (Dc<Db<Da). In addition, in the image G, the image Ga projected at a position farther from the vehicle body 51 extends wider in the vehicle width direction than the image Gc projected at a position closer to the vehicle body 51 (Wc<Wb<Wa).

Here, a suitable projection distance D of the image G in the vehicle length direction varies depending on the mounting position of the image projection device 1. For example, in the case of headlights and backup lamps 52, it is preferably within 3 m, and in the case of side turn signal lamps, it is preferably within 5 m. In particular, in the case of backup lamps 52, it is most preferable that the projection distance D is 2.5 m. Also, it is preferable to adjust the light source 2 so that the brightness of the image G is about 7000 cd at the brightest position P. Also, in this example, the length D of the image G in the vehicle length direction increases from Gc to Gb to Ga (Dc<Db<Da), and the length W in the vehicle width direction also increases (Wc<Wb<Wa).

Next, modified examples of the image projection device 1 will be shown with reference to Figures 6 to 8. The image projection device 1 can also be installed alongside a vehicle lamp other than the backup lamp 52, such as a headlamp 54 or a side turn signal lamp, or can be installed inside the lamp chamber of a vehicle lamp. In this modified example, an example in which the image projection device 1 is installed inside the lamp chamber of the headlamp 54 is shown. Even in this case, it is desirable that the distance d between the light source 2" of the headlamp 54 and the light source 2 is 75 mm or less.

6 and 7, in the image projection device 1 of the modified example, the lenses 4 are arranged side by side in the horizontal direction. The lenses 4c, 4b, and 4a each have a different radius r (radius rc<radius rb<radius ra), and are arranged so that the radius r increases toward the inside (the axle side). The lenses 4 are attached in such a manner that the entire lens 4 is inclined toward the side of the vehicle body. By appropriately adjusting the inclination angle θ1 of the entire lens 4, the inclination angle θ2 of the image G toward the side of the vehicle body can be changed.

As shown in Fig. 7A, the lenses 4 are arranged so that the optical axes of the lights Lc, Lb, and Lc passing through the lenses 4c, 4b, and 4a intersect in a plan view. Also, as shown in Fig. 7B, the inclination of the lenses 4 in the vertical direction is adjusted so that the lens 4c having a smaller diameter projects the image Gc closer to the vehicle body 51, and the lens 4a having a larger diameter projects the image Ga farther from the vehicle body 51.

8 shows a state in which the image projection device 1 of the modified example is turned on. The images Gc, Gb, and Ga are drawn on a straight line A that is a projection of the optical axis of the light L emitted from the light source 2 onto the road surface. The image G is longer in the vehicle length direction for the image Ga projected at a position away from the vehicle body 51 than the image Gc projected at a position closer to the vehicle body 51. Also, the image G is wider in the vehicle width direction for the image Ga projected at a position away from the vehicle body 51 than the image Gc projected at a position closer to the vehicle body 51.

According to the image projection device 1 configured as above, the lenses 4c, 4b, and 4a are provided so as to have different diameters rc, rb, and ra, and for example, the lens 4b with a larger diameter r is configured to project the image Gb at a position farther from the image projection device 1 than the lens 4c with a smaller diameter r. Therefore, even if the light sources 2c, 2b, and 2c with the same light flux are used, the images Gc, Gb, and Gc can be projected with the same illuminance regardless of the distance from the vehicle 51, and the variation in brightness of the image G can be suppressed. In addition, the lenses 4c, 4b, and 4a can adjust the focus of each image G to be projected, and clear images Gc, Gb, and Ga can be projected. Furthermore, since the lenses 4c, 4b, and 4a are provided integrally, the image projection device 1 can be manufactured with a small number of parts, and it is also possible to reduce labor and costs.

A second embodiment of the present invention will be described below with reference to the drawings. The image projection device 1 shown in Figures 9 to 11 includes a plurality of light sources 2 (2a to 2c) that emit light L to project an image G, and a control system 11 that controls the light sources 2.

The control system 11 includes an on/off control circuit 13 that turns on, off, and sequentially turns on the light source 2, and an ECU 12 that controls the on/off control circuit 13. The ECU 12 receives a control signal from a control system 21 for the backup lamp 52, and controls the on/off control circuit 13 so as to be linked with the on/off of the backup lamp 52.

Here, sequential lighting refers to a control in which the light sources 2 are turned on in the order of light source 2c, light source 2b, and light source 2a with a predetermined time interval, then turned off once, and then the light sources 2 are turned on again in the order of light source 2c, light source 2b, and light source 2a with a predetermined time interval, and this control is repeated. In sequential lighting, when the light sources 2 are turned on in the order of light source 2c, light source 2b, and light source 2a, the image G closest to the vehicle body 51 is projected onto the road surface R in the order of image Gc, image Gb, and image Ga.

As shown in Figure 10, the image projection device 1 is composed of a board 7 on which a light source 2 is mounted, an attachment 5 for attaching a shade 3 to the board 7, the shade 3 that cuts the light L from the light source 2 into a shape corresponding to an image G, a lens 4 that transmits the light L from the light source 2, and an extension 6 that shields the internal structure of the image projection device 1 from the outside of the vehicle.

The light sources 2a to 2c are LEDs having the same current value and the same brightness, and are arranged vertically. Arranging the light sources 2 vertically has the advantage that the optical design of the lens can be simplified compared to when they are arranged horizontally.

The light sources 2 are provided so that the light beams La to Lc emitted from the light sources 2a to 2c are inclined from an obliquely upward direction toward the road surface R. By arranging the light sources 2 in this manner, images Ga to Gc extending in the vehicle length direction are projected onto the road surface.

In a plan view, the light sources 2a to 2c are arranged in a straight line with the image drawn by the light from the light source 2. By arranging the light source 2 and the images Ga to Gc in a straight line, it becomes easier to understand that the images belong to the same function, compared to a case in which the light source 2 and the image G are projected with deviations to the left and right. In this case, a vehicle lamp (e.g., a backup lamp 52) arranged in parallel with the light source 2 may also be configured to be arranged in a straight line with the light source 2 and the image G.

The shade 3 is provided with a trapezoidal opening 31 having an upper base 32 that is longer than a lower base 33. By appropriately adjusting the ratio between the upper base 32 and the lower base 33, it is possible to adjust the shape of the projected image G. For example, it is possible to provide the opening 31 in a rectangular shape and project a trapezoidal image G that becomes wider as it gets farther away from the vehicle.

The openings 31 are all provided with the same shape and area. By providing the openings 31 with the same area and shape, the structure of the shade 3 can be simplified and the manufacturing cost can be reduced.

The lenses 4 (4a to 4c) are integrally formed and configured to transmit the light beams L1 to L3 from the light sources 2a to 2c. The lenses 4a to 4c each have a different diameter, and are provided so that the diameter decreases toward the bottom. The lenses 4 are arranged so that the larger the diameter, the greater the distance between the lenses 4 so that they do not overlap each other. The position of the lenses 4 from the light source 2 is determined according to their own focal length.

At this time, the inclination of the lens 4 is adjusted so that the light L passing through the lens 2 with a larger diameter projects the image G farther than the lens 2 with a smaller diameter. The inclination of the lens 4 is set so that the closer the lens 4 is to the vehicle projection device 1 or the vehicle body 51, the greater the inclination. By adjusting in this manner, the light flux passing through the lens 2 with a larger diameter is greater than the light flux passing through the lens 2 with a smaller diameter, so that the image G can be projected with the same illuminance regardless of the distance from the vehicle body 51. It is also possible to arrange the lens 4 so that the diameter becomes larger toward the bottom. In this case, it is preferable to adjust the inclination of the lens 4 so that the larger the diameter lens 4 is, the farther the image G is projected from the vehicle body 51.

As shown in Fig. 12, the image projection device 1 is disposed below the bumper 53. The light L from the image projection device 1 is brighter than other vehicle lamps, and is therefore prone to causing glare. By disposing the image projection device 1 below the bumper, it is expected that the effect of suppressing glare can be expected. The image projection device 1 is also disposed in parallel with the backup lamp 52 so that the emitted light L from the light source 2 is visually recognized as one body together with the light L' from the backup lamp 52. In particular, it is desirable that the distance d between the light source 2 and the light source 2' of the backup lamp 52 is 75 mm or less so that the emitted lights L, L' are visually recognized as one body.

13 shows a state in which the image projection device 1 having the above-mentioned configuration is turned on. The images Ga to Gc are drawn on a straight line A formed by projecting the optical axes of the light sources 2a to 2c onto the road surface R. The image G projected at a position farther from the vehicle body 51 extends longer in the vehicle length direction than the image G projected at a position closer to the vehicle body 51 (Da>Db>Dc). Also, the image G projected at a position farther from the vehicle body 51 extends wider in the vehicle width direction than the image G projected at a position closer to the vehicle body 51 (Wa>Wb>Wc).

The image projection device 1 can also be installed alongside vehicle lighting fixtures other than the backup lamp 52, such as headlights and side turn signal lamps. Fig. 14(a) is a schematic diagram showing the projected image G when installed alongside a side turn signal lamp, and Fig. 14(b) is a schematic diagram showing the projected image G when installed alongside a headlight. When installed alongside the backup lamp 52 or the headlight, the image G is projected inward from the vehicle width. On the other hand, when installed alongside a side turn signal lamp, the image G is projected so as to unfold to the left and right as it moves away from the vehicle body 51.

Here, a suitable projection distance D of the image G in the vehicle length direction varies depending on the mounting position of the image projection device 1. For example, in the case of headlights and backup lamps 52, it is preferably within 3 m, and in the case of side turn signal lamps, it is preferably within 5 m. In particular, in the case of backup lamps 52, it is most preferable that the projection distance D is 2.5 m. It is also preferable to adjust the light source 2 so that the brightness of the image G is about 7000 cd at the brightest position P. It is also preferable to adjust the optical performance so that the brightness of the image G is Michelson contrast of 0.2 or more at the brightest position P.

Next, the on/off control by the control system 11 in the image projection device 1 configured as described above will be described. When the vehicle starts to reverse, the control system 21 of the backup lamps 52 performs control to turn on the backup lamps 52. At this time, the ECU 22 of the backup lamps 52 transmits a control signal to the control system 11 of the image projection device 1. The ECU 12 of the control system 11 that receives the control signal turns on all of the light sources 2a to 2c of the image projection device 1. When sequential lighting is performed, the ECU 12 turns on the light sources 2c, 2b, and 2a in this order. At this time, from outside the vehicle, it is visually recognized that the light source 2 (light source 2c in the case of sequential lighting) is turned on at the same time as the backup lamps 52.

According to the image projection device 1 described above, the image G is projected in conjunction with other vehicle lighting devices such as the backup lamps 52, so that the message that the vehicle is backing up can be more clearly conveyed to the outside of the vehicle. Also, the openings 31 of the shades 3 that form the image G are provided with the same area and shape, so that the structure of the shades 3 can be simplified and the manufacturing costs can be reduced. Furthermore, since a plurality of images Ga to Gc can be projected simultaneously or sequentially using one shade 3 and one lens 4, the number of parts can be reduced and the costs can be reduced.

A third embodiment of the present invention will be described below with reference to the drawings. The image projection device 1 shown in Figures 15 and 16 is attached near a backup lamp 52 and includes a plurality of light sources 2 (2a to 2c) that emit light L (La to Lc) to project an image G (Ga to Gc), a plurality of lenses 4 (4a to 4c) that face the light sources 2, respectively, and a shade 3 that is interposed between the light sources 2 and the lenses 4.

As shown in Figure 16, the image projection device 1 is composed of a board 7 on which a light source 2 is mounted, an attachment 5 for attaching a shade 3 to the board 7, a flat shade 3 that cuts out the light L from the light source 2 into a predetermined shape, a lens 4 that transmits the light L from the light source 2, and an extension 6 that shields the internal structure of the image projection device 1 from the outside of the vehicle.

The light sources 2a to 2c are LEDs having the same luminous flux, i.e., LEDs having the same current value and the same brightness, and are arranged vertically. Arranging the light sources 2 vertically has the advantage of simplifying the optical design of the lenses compared to arranging them horizontally.

The lenses 4 (4a to 4c) are integrally formed and configured to transmit the light beams La to Lc from the light sources 2a to 2c. The lenses 4a to 4c each have a different diameter, and are provided so that the diameter decreases toward the bottom. The lenses 4 are arranged so that the larger the diameter, the greater the distance between the lenses 4 so that they do not overlap each other. The position of the lenses 4 from the light source 2 is determined according to their own focal length.

At this time, the inclination of the lens 4 is adjusted so that the light L passing through the lens 2 with a larger diameter projects the image G farther than the lens 2 with a smaller diameter. The inclination of the lens 4 is set so that the closer the lens 4 is to the vehicle projection device 1 or the vehicle body 51, the greater the inclination. By adjusting in this manner, the light flux passing through the lens 2 with a larger diameter is greater than the light flux passing through the lens 2 with a smaller diameter, so that the image G can be projected with the same illuminance regardless of the distance from the vehicle body 51. It is also possible to arrange the lens 4 so that the diameter becomes larger toward the bottom. In this case, it is preferable to adjust the inclination of the lens 4 so that the larger the diameter lens 4 is, the farther the image G is projected from the vehicle body 51.

As shown in FIG. 17(a), the vehicle projection device 1 is provided so that the light L emitted from the light sources 2a to 2c descends while inclining toward the road surface R. At this time, as shown in FIG. 17(b), images Ga to Gc extending in the vehicle length direction are projected onto the road surface R. In addition, the light source 2 is arranged on the same straight line A as the image G drawn by the light L from the light source 2. By arranging the light source 2 and the image G in a row on the same straight line A, it becomes easier to understand that the images belong to the same function compared to when the light source 2 and the image G are projected with a variance to the left and right. At this time, it may be configured so that the light source 2 and the image G are arranged on a straight line, including a vehicle lamp (e.g., a backup lamp 52) arranged in parallel with the light source 2.

18, when the focal point F is within the lens, the light that passes through the opening 31 of the shade 3 is projected inverted at the focal point F of the lens 4. Therefore, the light L that passes near the upper base 32 of the opening 31 is projected near the side G1 closer to the vehicle body 51, and the light L that passes near the lower base 33 is projected near the side G2 farther from the vehicle body 51 (see FIG. 19).

18(b), the openings 31 are arranged in series along the longitudinal direction of the shade 3. The size of the openings 31 is set to match the size of the LED chip that is the light source 2. The height h of the openings 31 is preferably about 0.9 mm. The distances k1, k2 between the openings 31 are set to be different from each other according to the size and inclination of the lens 4.

Fig. 19(a) shows an image G' projected when a rectangular opening 31' is provided with a focal point F within the lens, and Fig. 19(b) shows an image G projected when a trapezoidal opening 31 with a lower base 33 shorter than an upper base 32 is provided with a focal point F within the lens. In Fig. 19(b), compared to Fig. 19(a), the extension of side G2 farther from the vehicle body 51 is suppressed (G2'>G2), and a band-shaped image G extending in the vehicle length direction is projected.

20, the image projection device 1 may be configured so that the light that passes through the opening 31 of the shade 3 travels straight through the inside of the lens 4. In this case, the focal point F is not located within the lens. In this case, the light L that passes through the vicinity of the upper base 32 of the opening 31 is projected near the side G2 that is far from the vehicle body 51, and the light L that passes through the vicinity of the lower base 33 is projected near the side G1 that is close to the vehicle body 51 (see FIG. 21).

Fig. 21(a) shows an image G' that is projected when a rectangular opening 31' is provided when there is no focal point F in the lens, and Fig. 21(b) shows an image G that is projected when a trapezoidal opening 31 with a lower base 33 longer than an upper base 32 is provided when there is no focal point F in the lens. In Fig. 21(b), compared to Fig. 21(a), the extension of the side G2 farther from the vehicle body 51 is suppressed (G2'>G2), and a band-shaped image G that extends in the vehicle length direction is projected.

22 shows a state in which the image projection device 1 having the above-mentioned configuration is turned on. The images Ga to Gc are drawn on a straight line A that is a projection of the optical axis of the light L emitted from the light source 2 onto the road surface R. The image G is longer in the vehicle length direction for the image Ga projected at a position away from the vehicle body 51 than the image Gc projected at a position closer to the vehicle body 51. Also, the image G is wider in the vehicle width direction for the image Ga projected at a position away from the vehicle body 51 than the image Gc projected at a position closer to the vehicle body 51.

Here, a suitable projection distance D of the image G in the vehicle length direction varies depending on the mounting position of the image projection device 1. For example, in the case of headlights and backup lamps 52, it is preferably within 3 m, and in the case of side turn signal lamps, it is preferably within 5 m. In particular, in the case of backup lamps 52, it is most preferable that the projection distance D is 2.5 m. In addition, it is preferable to adjust the optical performance so that the brightness of the image G is Michelson contrast 0.2 or more at the brightest position P. Furthermore, in this example, the length D of the image G in the vehicle length direction increases from Gc to Gb to Ga (Dc<Db<Da), and the length W in the vehicle width direction also increases (Wc<Wb<Wa).

23 to 26 show modified examples of the image projection device 1. The image projection device 1 can be installed alongside a vehicle lamp other than the backup lamp 52, such as a headlamp 54 or a side turn signal lamp, or can be installed inside the lamp chamber of a vehicle lamp. In this modified example, an example of installation inside the lamp chamber of the headlamp 54 is shown.

As shown in Figures 23 and 24, in the image projection device 1 of the modified example, the lenses 4 are arranged side by side in the horizontal direction. The lenses 4a to 4c each have a different diameter, and are arranged so that the diameter increases toward the inside (the axle side). The lenses 4 are also attached in such a manner that the entire lens 4 is inclined toward the side of the vehicle body. By appropriately adjusting the inclination angle θ1 of the entire lens 4, the inclination angle θ2 of the image G toward the side of the vehicle body (see Figure 12(a)) can be changed.

As shown in Fig. 24(a), the lenses 4 are arranged so that the optical axes of the lights La to Lc passing through the lenses 4a to 4c intersect in a plan view. Also, as shown in Fig. 24(b), the vertical inclination of the lenses 4 is adjusted so that the smaller the diameter of the lenses 4, the closer the image G is to the vehicle body 51, and the larger the diameter of the lenses 4, the farther the image G is from the vehicle body 51.

As shown in FIG. 25, the opening 31 of the shade 3 of the modified example is provided in a trapezoid shape with the upper base 32 longer than the lower base 33. Here, the openings facing the lenses 4a, 4b, and 4c are designated as 31a, 31b, and 31c. Each opening 31 is inclined downward toward the axle side, and the base angle of the upper base 32 facing the side of the vehicle body is set so that θa>θb>θc, where the base angles of the openings 31a, 31b, and 31c are θa, θb, and θc, respectively. In addition, the openings 31 are provided so that their sizes (areas) are different from each other. By configuring in this way, it is possible to suppress the extension of the width W of multiple images G projected by light L that intersect with each other in a plan view and have different vertical inclinations.

26 shows a state in which the image projection device 1 of the modified example is turned on. The images Ga to Gc are drawn on a straight line A that is a projection of the optical axis of the light L emitted from the light source 2 onto the road surface R. The image G is longer in the vehicle length direction for the image Ga projected at a position away from the vehicle body 51 than the image Gc projected at a position closer to the vehicle body 51. Also, the image G is wider in the vehicle width direction for the image Ga projected at a position away from the vehicle body 51 than the image Gc projected at a position closer to the vehicle body 51.

According to the image projection device 1 configured as above, the opening 31 is provided in a trapezoidal shape, and either the upper base 32 or the lower base 33, whichever is longer, is configured to correspond to the side G2 that is drawn farther from the image projection device 1 or the vehicle body 51, which has the effect of suppressing the extension of the image in the width direction and projecting a band-shaped image extending in the vehicle length direction. Furthermore, since a plurality of openings 31 are formed together in the shade 3, the image projection device 1 can be manufactured with a small number of parts, and it is also possible to reduce the labor and cost.

The present invention is not limited to the above embodiment, and the shape and configuration of each part can be appropriately changed without departing from the spirit of the present invention. For example, the example in which the light is linked to the backup lamp 52 has been described, but the light may be projected on the road surface in conjunction with the lighting of the headlamps. Alternatively, the light may be projected on the road surface as a starting light at the same time as the lighting of the low beam.

REFERENCE SIGNS LIST 1 Image projection device 2 Light source 3 Shade 4 Lens 5 Attachment 6 Extension 7 Board 11 Control system (image projection device)
12 ECU (image projection device)
13 Lighting control circuit (image projection device)
21 Control system (back-up lamp)
22 ECU (back-up lamp)
23 Lighting control circuit (backup lamp)
31 Opening 32 Upper base (opening)
33 Bottom (opening)
51 Car body 52 Backup lamp 53 Bumper 54 Headlight G Image P Brightest position of image D Projection distance W Image width d Distance between light sources L Light A Straight line R Road surface

Claims (7)

An image projection device for a vehicle, comprising:
A plurality of light sources and a plurality of lenses facing the plurality of light sources,
the plurality of lenses each having a different diameter, a lens having a larger diameter projects an image at a position farther away from the image projection device than a lens having a smaller diameter ;
The plurality of light sources are provided to emit light of the same luminous flux,
The image projection device according to the present invention is characterized in that the lenses each have a diameter so as to project an image with the same illuminance . 2. The image projection device according to claim 1 , wherein the plurality of lenses are provided such that an optical axis of light passing through at least one of the lenses is non-parallel to an optical axis of light passing through the other lenses. 3. The image projection device according to claim 1 , wherein the lens is attached in a position inclined toward a side of the vehicle body. A plurality of the light sources are arranged side by side on the left and right,
The image projection device according to any one of claims 1 to 3 , wherein the light emitted by the plurality of light sources projects an image that extends obliquely toward a side of a vehicle body. A plurality of the light sources are arranged vertically in parallel,
The image projection device according to any one of claims 1 to 3, wherein the light emitted by the plurality of light sources projects an image extending in a vehicle length direction. 6. The image projection device according to claim 5 , wherein the lens having a larger diameter is disposed below the lens having a smaller diameter. Located near other vehicle lighting fixtures,
7. The image projection device according to claim 1 , wherein the light emitted from the light source is visually recognized as being integrated with the light emitted from the other vehicle lamp.

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