JP6861387B2 - Lighting device - Google Patents

Description

The present invention relates to a lighting device having a uniform illuminance distribution over a wide angle range.

Patent Documents 1 to 4 disclose a lighting device. For example, Patent Document 1 includes a plurality of light emitting elements, a light guide plate that guides light emitted from the plurality of light emitting elements in the plate, and a lens array that covers at least a part of the main surface of the light guide plate. To disclose. In the lighting device, the light guide plate has a plurality of concave reflection portions, and the lens array has a plurality of lens portions arranged so as to face each concave reflection portion. In such a lighting device, the light incident on the light guide plate is reflected by the concave reflecting portion in the light guide plate while propagating through the light guide plate, and is emitted to the lens array. In the lens array, the light incident from the light guide plate is collected by the lens unit and emitted as illumination light.

Japanese Unexamined Patent Publication No. 2014-165021 Japanese Unexamined Patent Publication No. 2014-160616 Japanese Unexamined Patent Publication No. 2014-154393 Japanese Unexamined Patent Publication No. 2014-154321

In the lighting device disclosed in Patent Documents 1 to 4, the shape of the concave reflection portion in the light guide plate is conical, and the concave reflection portion is reflected by the conical concave reflection portion and faces the conical concave reflection portion. The larger the diameter of the conical concave reflecting portion, the higher the emission efficiency of the light emitted from the conical lens. However, the wider the conical emission area, the wider the light distribution angle and the higher the peak illuminance. There is a problem that it does not become.

An object of the present invention is to provide a light beam having high emission efficiency of illumination light and high directivity.

The lighting device of the present invention comprises a plurality of light emitting elements, a light guide plate that allows light from the light emitting element to enter through a light input unit, propagates the incident light to the inside, and emits light from an exit surface, and the light guide plate. A lens member for controlling the emission direction of the emitted light is provided, and a plurality of concave reflection portions are arranged on a surface facing the emission surface of the light guide plate, and the lens member has a plurality of concave reflection portions corresponding to the concave reflection portions. The lens is formed, a part of the concave reflection portion has a semi-conical shape , and the inclined curved surface portion of the semi-conical concave reflection portion faces in the direction of the nearest light emitting element. ..

According to this configuration, it is possible to narrow the light distribution of the light emitted by the semi-conical concave reflection portion of the light guide plate and collected by the lens facing the semi-conical concave reflection portion. It is possible to realize a lighting device having high efficiency and high directional light distribution characteristics.

External view of the lighting device in this embodiment Sectional view of the lighting device Development view showing the components of the lighting device (A) A perspective view of the lens member and (b) a perspective view of the light guide plate. The figure explaining the reflection of light by the concave reflection part of a light guide plate. (A) A partial cross-sectional view of the lighting device according to the present embodiment, (b) an enlarged view of a conical concave reflecting portion 17x formed on the inner surface of the light guide plate as viewed from the outer surface of the light guide plate, and (c) the light guide plate. An enlarged view of the semi-conical concave reflecting portion 17y formed on the inner surface as viewed from the outer surface of the light guide plate, and (d) a partial view of the light guide plate in the present embodiment as viewed from the back. (A) A diagram showing the radiation direction of light radiated from a fine conical concave reflector and (b) a diagram showing a radiation direction of light radiated from a large conical concave reflector. The figure which shows the radiation direction of the light radiated from the semi-conical concave reflection part It is a figure which shows the difference of the light distribution pattern of the light radiated from the lens part between a conical concave reflection part and a semi-conical concave reflection part, (a) the distances of LED elements 21a and 21b are arranged at substantially equal distances. The figure which shows the light distribution pattern of the light radiated from a lens part in a conical concave reflection part, (b) light distribution of the light radiated from a lens part in a conical concave reflection part arranged at a position close to LED element 21a. A diagram showing a pattern, (c) a diagram showing a light distribution pattern of light radiated from a lens portion in a semi-conical concave reflecting portion arranged at a position close to the LED element 21a. Comparison of light distribution characteristics between the case where only the conical concave reflector is used and the case where the semi-conical concave reflector is used. A graph showing a comparison of the illuminance distribution at a distance of 1 m from the illuminating device when the conical concave reflector is used only and when the semi-conical concave reflector is used. External view of the underwater image capturing device provided with the lighting device of the first embodiment

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

However, more detailed explanation than necessary may be omitted. For example, detailed explanations of already well-known matters and duplicate explanations for substantially the same configuration may be omitted. This is to avoid unnecessary redundancy of the following description and to facilitate the understanding of those skilled in the art.

It should be noted that the inventors (or others) intend to limit the subject matter described in the claims by those skilled in the art by providing the accompanying drawings and the following description in order to fully understand the present disclosure. It is not something to do.

In a lighting device for image capture, it is desired that the illuminance distribution in the shooting angle of view range is uniform. The light distribution characteristics of a normal lighting device show Lambert light distribution in which the angular characteristic of luminous intensity is cosθ, but since the illuminance is inversely proportional to the square of the distance, the lighting device used for wide-angle image capture has an angle of view rather than the central illuminance. It is necessary to increase the illuminance at the edges. For example, when the orientation of the angle-of-view end is 45 degrees, the distance of the angle-of-view end from the illuminating device to the center is √2, so that the required luminous intensity is twice that of the center.

In order to satisfy the above conditions, the present inventor has a plurality of light emitting elements and a light guide plate that injects light from the light emitting element through a light input unit, propagates the incident light inside, and emits light from an exit surface. A lens member for controlling the emission direction of light emitted from the light guide plate is provided, and a plurality of concave reflecting portions are arranged on a surface facing the emission surface of the light guide plate, and the lens member has the concave shape. We devised an illumination device in which a plurality of lens-shaped portions corresponding to each of the reflecting portions were formed, and designed the area of the concave reflecting portion on the outer peripheral portion of the light guide plate to be larger than the area of the concave reflecting portion in the central portion. However, as the light distribution angle of the light radiated to the edge of the angle of view becomes wider, the amount of light radiated to the area outside the range of the shooting angle of view increases, and a large-capacity light source is required. Therefore, the present inventor has studied an illuminating device that reduces the amount of light emitted to a region outside the shooting angle of view range, and completed the following illuminating device.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
− Composition −
FIG. 1 is a perspective view of the lighting device of the first embodiment. 2A and 2B are cross-sectional views cut along a plane passing through the center of the illuminating device, FIG. 2A is a cross-sectional view when viewed from slightly diagonally above, and FIG. 2B is a cross-sectional view when viewed from the side. .. FIG. 3 is a development view of the lighting device.

The lighting device 10 covers the bottomed base portion 25 and the opening of the storage recess 25a of the base portion 25 with a dome-shaped cover 11 to form a closed space so as to perform dustproof and waterproof functions. The LED substrate 23, the reflector 19, the light guide plate 17, the lens member 15, and the pressing plate 13 are housed in a closed space. Specifically, in this enclosed space, the reflector 19 is arranged on the LED substrate 23, the light guide plate 17 is arranged on the reflector plate 19, and the lens member 15 is arranged on the light guide plate 17. The lens member 15 to the LED substrate 23 are attached to the base portion 25 by a screw 13a penetrating the pressing plate 13.

The light emitted from the LED substrate 23 enters the inside of the light guide plate 17 from the end of the dome-shaped light guide plate 17, and proceeds while reflecting inside the light guide plate 17, and has a concave shape formed on the inner surface of the light guide plate 17. It is reflected toward the outer surface of the light guide plate 17 by the reflecting portion, passes through the dome-shaped lens member 15 as a lens member that controls the emission direction of the light emitted from the light guide plate 17, and further passes through the cover 11. The outside of the lighting device 10 is irradiated. The reflector 19 is a member for reflecting the light traveling inside the light guide plate 17 and re-entering the light guide plate 17 when the light leaks to the outside from the bottom surface of the light guide plate 17. .. Here, the dome shape of the light guide plate 17 and the lens member 15 is a curved surface formed by rotating the exit surface around a curved line. The light receiving portion of the light guide plate 17 is formed in an annular shape.

As shown in FIG. 3, a plurality of LED elements 21 which are light emitting elements are arranged on the LED substrate 23. In this example, a total of 30 LED elements 21 are arranged in an annular shape at equal pitches. The light guide plate 17 is made of a transparent material such as PMMA (Poly / Methyl Methacrylate) or PC (Poly Carbonate). The material of the lens member 15 and the cover 11 is the same as that of the light guide plate 17.

FIG. 4B is a view of the light guide plate 17 viewed from diagonally below.

The dome-shaped light guide plate 17 has a peripheral portion (annular end portion) as a light input portion, and light from the LED element 21 is incident on the inside of the light guide plate 17 from the light input portion. The light guide plate 17 propagates the light from the LED element 21 inside the light guide plate 17 and emits the light from the exit surface (main surface on the lens member 15 side).

FIG. 4A is a view of the lens member 15 viewed from diagonally above. The lens member 15 incidents the light emitted from the light guide plate 17 and emits it from the exit surface (main surface on the side corresponding to the cover 11). FIG. 5 is a cross-sectional view of the light guide plate 17 and the lens member 15 arranged on the light guide plate 17.

The dome-shaped light guide plate 17 has a peripheral portion (annular end portion) as a light input portion, light from the LED element 21 is incident on the inside of the light guide plate 17 from the light entrance portion, and the light is incident on the inside of the light guide plate 17. It is propagated and emitted from the exit surface (main surface on the lens member 15 side). As shown in FIGS. 4B and 5, the light guide plate 17 has a conical concave reflecting portion 17x and a semi-cone on the inner surface (reflector 19 side) in order to reflect the light propagating inside to the emitting surface. A plurality of concave reflecting portions 17y are formed.

As shown in FIGS. 4A and 5, a plurality of lenses 15a are formed on the exit surface side of the lens member 15. The lens 15a is arranged concentrically around the apex of the lens member 15. The optical path of the light incident on the lens member 15 from the light guide plate 17 is changed by the lens 15a, and the light is emitted as emitted light.

The conical concave reflecting portion 17x and the semi-conical concave reflecting portion 17y of the light guide plate 17 are formed at positions corresponding to the lens 15a of the lens member 15. For example, the conical concave shape is formed at a position where the central axis of the conical concave reflection portion 17x or the semi-conical concave reflection portion 17y and the central axis of the corresponding lens 15a in the lens member 15 satisfy a predetermined positional relationship. A reflecting portion 17x or a semi-conical concave reflecting portion 17y is arranged.

The light incident on the light guide plate 17 propagates in the light guide plate 17, and when it enters the conical concave reflection portion 17x or the semi-conical concave reflection portion 17y, the conical concave reflection portion 17x or the semi-conical concave reflection portion 17x or the semi-conical concave reflection portion 17y. It is reflected toward the lens member 15 by the reflecting portion 17y (see FIG. 5). The light reflected by the conical concave reflecting portion 17x or the semi-conical concave reflecting portion 17y and incident on the lens member 15 is emitted from the exit surface of the lens member 15 after the traveling direction is changed by the lens 15a.

When the light traveling inside the light guide plate 17 leaks to the outside from the bottom surface of the light guide plate 17, the reflector 19 that reflects the light and re-enters the light guide plate 17 has a high reflectance (for example,). , 97-98%).

FIG. 6A is a partial cross-sectional view of an optical unit component in the lighting device according to the present embodiment, and FIG. 6D is a partial view of the light guide plate as viewed from the back. A semi-conical concave reflecting portion 17y is arranged on the inner surface of the light guide plate 17 near the LED element 21, and a conical concave reflecting portion 17x is arranged near the center of the dome-shaped light guide plate 17.

− Action −
The operation of the lighting device 10 configured as described above will be described.

First, the operation when the light from the LED element 21 is converted into illumination light by the light guide plate 17 and the lens member 15 and output will be described.

The light from the LED element 21 arranged on the LED substrate 23 is incident on the light guide plate 17 from the light entering portion on the periphery of the light guide plate 17. FIG. 7A shows a case where the light rays 20a and 20b incident on the light guide plate 17 from the light entering portion on the periphery of the light guide plate 17 and guiding the inside of the light guide plate pass through the fine conical concave reflection portion 17x. It is a figure which showed the course of light rays 20a, 20b.

Here, the light ray 20a is the light emitted from the LED element 21a relatively close to the conical concave reflecting portion 17x, and the light ray 20b is the light emitted from the LED element 21b arranged on the opposite side of the LED element 21a. Is. Both the light rays 20a and 20b are totally reflected by the conical concave reflecting portion 17x, are radiated from the light guide plate 17 in a different direction, and the direction is controlled by passing through the lens 15a to be radiated from the lens 15a. Since the projected area of the conical concave reflecting portion 17x is extremely narrow, the light distribution of the light emitted from the lens 15a is also extremely narrow, and the light becomes coherent and irradiates the target surface.

FIG. 7B is a diagram showing the paths of the light rays 20a and 20b when the light rays 20a and 20b that have guided the inside of the light guide plate pass through the relatively large conical concave reflecting portion 17x. Both the light rays 20a and 20b are totally reflected by the conical concave reflecting portion 17x, are radiated from the light guide plate 17 in a different direction, and the direction is controlled by passing through the lens 15a to be radiated from the lens 15a. In this case, since the projected area of the conical concave reflecting portion 17x is relatively large, the energy of the emitted light is relatively high, but the depth of focus of the light incident on the lens 15a is large, so that the light is emitted from the lens 15a. The light distribution is widened. Therefore, the light condensing property is deteriorated, and a large amount of light is irradiated to the irradiation surface other than the target irradiation surface. Therefore, the efficiency of irradiating the target irradiation region with light deteriorates.

When trying to make the illuminance of the light radiated to a wide irradiation region uniform, the light distribution characteristic of the light radiated from the illuminating device needs to have the highest luminous intensity at the end of the irradiation region as shown in FIG. The illuminance is inversely proportional to the square of the distance, and is cos θ times the illuminance in front of the illuminance when the angle between the optical axis and the irradiation surface is θ. Therefore, in order to make the illuminance over the entire irradiation range uniform, the luminous intensity at the end of the irradiation region needs to be ^{1 / (cosθ) 3 times the luminous intensity of the front surface.} For example, in order to irradiate an irradiation surface having an irradiation width of 1.6 m from a distance of 1 m with uniform illuminance, the luminous intensity at the end of the irradiation region is about twice the luminous intensity of the front surface.

In the lighting device of this example, the lens 15a for irradiating the end of the irradiation region is arranged at the position closest to the light source, and the diameter of the conical concave reflecting portion 17x facing the lens 15a is arranged in the center of the light guide plate for irradiating the front surface. It is about 30 times the diameter of the conical concave reflecting portion 17x. Therefore, the light distribution of the light emitted from the lens 15a at the end is considerably large, and the illuminance outside the irradiation region is also considerably high.

FIG. 8 shows the path of light rays when the shape of the concave reflecting portion of the light guide plate 17 is a semi-cone in which the cone is cut in half. The light ray 20a is totally reflected by the inclined curved surface portion of the semi-conical concave reflecting portion 17y, is emitted from the light guide plate 17 in a different direction, and the direction is controlled by passing through the lens 15a to be emitted from the lens 15a. On the other hand, the light beam 20b passes through the vertical surface of the semi-conical concave reflecting portion 17y, re-enters the light guide plate 17, and is not irradiated by the lens 15a.

The operation in this embodiment will be described in detail with reference to FIG.

In this embodiment, the conical concave reflecting portion 17x is arranged near the center of the light guide plate 17, and the semi-conical concave reflecting portion 17y is arranged at the peripheral portion. To explain this, FIG. 9A describes a light distribution pattern of the conical concave reflecting portion 17x formed near the center of the light guide plate 17. Next, in FIG. 9B, a light distribution pattern in the case where the conical concave reflection portion 17x is arranged instead of the semi-conical concave reflection portion 17y around the light guide plate 17 will be described. Finally, FIG. 9C describes a light distribution pattern when the semi-conical concave reflecting portion 17y is arranged around the light guide plate 17.

The light distribution pattern of the conical concave reflecting portion 17x formed near the center of the light guide plate 17 has a left-right even shape in which the central portion is slightly recessed as shown in FIG. 9A. The light rays 20a and 20b emitted from the LED elements 21a and 21b hit the conical concave reflecting portion 17x formed in the central portion of the light guide plate 17, are radiated from the light guide plate 17 in a different direction, and are emitted by the lens 15. To. Since the conical concave reflecting portion 17x is at a substantially equal distance from each of the LED elements 21a and 21b, the light distribution characteristic is such that the central portion is slightly recessed on the left and right sides.

On the other hand, when the conical concave reflecting portion 17x is arranged near the LED element 21a as shown in FIG. 9B, the light ray 20a emitted from the LED element 21a hits the conical concave reflecting portion 17x and is a lens. The light emitted from the 15a forms a convex portion 22a having a high brightness on the left side of the light distribution characteristic, and the light ray 20b emitted from the 21b far from the conical concave reflecting portion 17x hits the conical concave reflecting portion 17x and is transmitted from the lens 15a. The emitted light forms a convex portion 22b having a low light intensity on the right side of the light distribution characteristic.

As shown in FIG. 9C, when a semi-conical concave reflection portion 17y having an inclined curved surface portion facing the LED element 21a is arranged in place of the conical concave reflection portion 17x of FIG. 9B, light is emitted from the LED element 21a. The light beam 20a hits the inclined curved surface portion of the semi-conical concave reflection portion 17y, and the light emitted from the lens 15a forms a convex portion 22a having a high luminosity on the left side of the light distribution characteristic. Further, the light ray 20b emitted from the LED element 21b far from the semi-conical concave reflection portion 17y passes through the vertical plane of the semi-conical concave reflection portion 17y and heads toward the LED element 21a without being emitted to the lens 15a side. After that, the light ray 20c reflected by the LED substrate 23 and re-entered on the light guide plate 17 hits the inclined curved surface portion of the semi-conical concave reflecting portion 17y and is emitted from the lens 15a. This light becomes a convex portion 22c added to the convex portion 22a of the light distribution characteristic, and a light distribution characteristic having a narrower light distribution width and a higher luminous intensity than that of FIG. 9B can be obtained.

In this embodiment, the conical concave reflection portion 17x is arranged near the center of the light guide plate 17, and the semi-conical concave reflection portion 17y is arranged at the peripheral portion to form the concave reflection portion. When the ratio of the distance between the LED element 21a closest to the concave reflection portion and the concave reflection portion and the distance between the LED element 21b located opposite to the LED element 21a and the concave reflection portion is large, the concave reflection portion has a semi-conical shape. It is desirable that the concave reflecting portion has a conical shape, which has an advantage that the emission efficiency is higher when the ratio is small. In the light guide plate 17, the boundary for switching the shape between the conical concave reflecting portion 17x and the semi-conical concave reflecting portion 17y is the ratio of the distance between the LED element 21a and the concave reflecting portion and the distance between the LED element 21b and the concave reflecting portion, that is, It is desirable that the distance between the LED element 21a and the concave reflecting portion / the distance between the LED element 21b and the concave reflecting portion is 1/4 or more to 1/2 or less.

When the "distance between the LED element 21a and the concave reflecting portion / the distance between the LED element 21b and the concave reflecting portion" is smaller than 1/4, the ratio of the semi-conical concave reflecting portion 17y is small, and the effect of the present invention cannot be expected so much. .. If the "distance between the LED element 21a and the concave reflecting portion / the distance between the LED element 21b and the concave reflecting portion" is larger than 1/2, the emission efficiency may be lowered.

FIG. 10 shows the light distribution characteristics of the illuminating device 10 when the shape of the concave reflecting portion of the light guide plate 17 is all conical concave reflecting portion 17x, and the light distribution when the peripheral portion is a semi-conical concave reflecting portion 17y. The characteristics are shown by a solid line. Compared to the case where all concave reflecting parts are conical (broken line), when the peripheral part is semi-conical (solid line), the luminosity at the end of the irradiation range is higher, and the luminosity in the direction where the angle is larger than that is higher. It's getting smaller.

Further, FIG. 11 shows the illuminance distribution at a position 1 m away from the lighting device 10 when the shape of the concave reflection portion of the light guide plate 17 is all conical, and the peripheral portion of the light guide plate 17 is shown by a semi-conical concave reflection. The illuminance distribution at a position 1 m away from the lighting device 10 is shown in the case of the portion 17y. The illuminance at the position of ± 800 mm, that is, the illuminance at the end of the irradiation range, is when the peripheral portion is a semi-conical concave reflector 17y (solid line) than when all the concave reflectors are conical concave reflectors 17x (broken line). However, the illuminance distribution is high.

− Effect −
As described above, according to the illuminance device 10 of the embodiment, not only the illuminance distribution in the irradiation range can be made uniform, but also the illuminance outside the illuminance range can be lowered to efficiently illuminate the illuminance range. ..

(Embodiment 2)
FIG. 12 shows an underwater imaging device including the lighting device 10 of the first embodiment.

The underwater image capturing device 100 is capable of diving underwater, can capture an underwater image while moving in the water, and can record the captured image on a recording medium.

The underwater imaging device 100 includes a frame 103, and a plurality of screws 105 are attached to the frame 103 as propulsion means for moving underwater in various directions. Further, a plurality of cameras 110 having a waterproof function for taking an image are also attached to the frame 103. The camera 110 stores the image data generated by shooting in a recording medium (for example, a memory card).

The underwater imaging device 100 can move in a desired direction by controlling the rotation speed of each screw. The underwater image capturing device 100 irradiates the subject with illumination light from the lighting device 10 and captures an image with the camera 110.

Since the underwater image capturing device 100 can make the illuminance at the end of the irradiation range higher than the illuminance at the center, it can capture a high-quality image.

As an example of the technology disclosed in this application, the above-described embodiment has been described. However, the technique in the present disclosure is not limited to this, and can be applied to embodiments in which changes, replacements, additions, omissions, etc. are made as appropriate. It is also possible to combine the components described in the above embodiment to form a new embodiment. Moreover, the embodiment was described as an example of the technique in this disclosure. To that end, the accompanying drawings and detailed description are provided. Therefore, among the components described in the attached drawings and the detailed description, not only the components essential for problem solving but also the components not essential for problem solving in order to exemplify the above technology. Can also be included. Therefore, the fact that these non-essential components are described in the accompanying drawings or detailed description should not immediately determine that those non-essential components are essential. Further, since the above-described embodiment is for exemplifying the technique in the present disclosure, various changes, replacements, additions, omissions, etc. can be made within the scope of claims or the equivalent scope thereof.

INDUSTRIAL APPLICABILITY The present invention can make the illuminance at the end of the irradiation range higher than the illuminance at the center, and can be applied to lighting devices from various close distances. For example, it can be applied to luminaires used in both underwater and air environments.

10 Lighting device 11 Cover 15 Lens member 15a Lens 17 Light guide plate 17x Conical concave reflector 17y Semi-conical concave reflector 18 Synchrotron radiation from lens 19 Synchrotron radiation 20a, 20b Synchrotron radiation from LED element 20c Synchrotron radiation from LED element Light 21,21a, 21b LED element (light emitting element) reflected by light 20b on the opposite surface
22a, 22b, 22c Luminous intensity distribution in height distribution characteristics 23 LED substrate 25 Base 100 Underwater imaging device

Claims (4)

With multiple light emitting elements
A light guide plate that injects light from the light emitting element through a light input unit, propagates the incident light inside, and emits light from an exit surface.
A lens member for controlling the emission direction of the light emitted from the light guide plate is provided.
A plurality of concave reflecting portions are arranged on the surface of the light guide plate facing the exit surface.
A plurality of lenses corresponding to the concave reflection portion are formed on the lens member.
A part of the concave reflecting portion has a semi-conical shape and has a semi-conical shape.
The inclined curved surface portion of the semi-conical concave reflecting portion faces the direction of the closest light emitting element.
Lighting device. The light guide plate is a curved surface formed by rotating the emission surface around a curved line, and the entrance portion is formed in an annular shape.
A plurality of the light emitting elements are arranged in an annular shape corresponding to the light input portion of the light guide plate.
The lighting device according to claim 1. When the ratio of the distance to the light emitting element closest to the concave reflecting portion to the distance to the light emitting element located on the opposite side thereof is small, the concave reflecting portion has a semi-conical shape, and the concave reflecting portion has a semi-conical shape in other places. The lighting device according to claim 1 , wherein the reflecting portion has a conical shape, and the boundary of the ratio is 1/4 or more to 1/2 or less. The lighting device according to any one of claims 1 to 3 and the camera that captures an image are framed.
An image capturing device attached to the camera.

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