JP2019215975A - Illumination device - Google Patents

Abstract

To provide an illumination device that allows a shape of a cross section perpendicular to an optical axis of a light to be adjusted.SOLUTION: An illumination device 10 includes a coherent light source 20 for emitting a coherent light; a shaping optical system 30 for shaping the coherent light emitted from the coherent light source 20; and a diffractive optical element 40 for diffracting the coherent light shaped in the shaping optical system 30, and directing it to an illuminated area Z. The coherent light source 20 emits the coherent light as a diffusion light in which diffusion angles in a first direction d1 and a second direction d2 orthogonal to each other are different each other. The shaping optical system 30 includes a first optical system 31 that changes the diffusion angle of the coherent light in at least one of the first direction d1 and the second direction d2, and a second optical system 32 that collimates the coherent light whose diffusion angle is adjusted in the first optical system 31. The first optical system 31 changes the diffusion angle in the first direction d1 and the diffusion angle in the second direction d2 with different magnifications.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to a lighting device.

  For example, as disclosed in Patent Document 1, an illumination device including a coherent light source that emits coherent light such as laser light and a diffractive optical element such as a hologram element is known. In the illumination device disclosed in Patent Literature 1, a hologram element diffracts a laser beam from a light source to illuminate a road surface with a desired illumination pattern. As a laser light source, for example, a semiconductor laser can be used.

JP-A-2015-132707

  By the way, it is known that a cross section perpendicular to the optical axis of a laser beam emitted from a semiconductor laser has an elliptical shape. This is because the laser light emitted from the semiconductor laser has an anisotropic diffusion angle.

  However, depending on the illumination device, it may be desirable that the cross section of the light incident on the diffractive optical element has a shape close to a circle or a quadrangle with a small dimensional difference in the longitudinal direction and the lateral direction. In addition, it is considered that the shape of the illumination device is easier to be reduced in size when the shape is closer to a circle or a square than when the dimensional difference in the longitudinal direction and the lateral direction of the cross section is large. Thus, the cross-sectional shape of the laser light emitted from the light source may not match the desired cross-sectional shape of the laser light incident on the diffractive optical element.

  Embodiments of the present disclosure have been made in view of the above points, and have as its object to provide an illumination device capable of adjusting the shape of a cross section perpendicular to the optical axis of light incident on a diffractive optical element. I do.

The lighting device according to the first embodiment of the present disclosure includes:
A coherent light source that emits coherent light,
A shaping optical system for shaping coherent light emitted from the coherent light source,
A diffractive optical element that diffracts the coherent light shaped by the shaping optical system and directs it toward the illuminated area,
The coherent light source emits coherent light as diffused light having different diffusion angles in a first direction and a second direction orthogonal to each other,
The shaping optical system is configured to change a diffusion angle of the coherent light in at least one of the first direction and the second direction, and to collimate the coherent light whose diffusion angle is adjusted by the first optical system. A second optical system,
The first optical system changes the diffusion angle in the first direction and the diffusion angle in the second direction at different magnifications.

In the lighting device according to the first embodiment of the present disclosure,
The coherent light source emits coherent light as diffusion light in which the diffusion angle in the first direction is larger than the diffusion angle in the second direction,
The first optical system may change a diffusion angle of the coherent light in the first direction at a magnification smaller than a diffusion angle in the second direction.

In the lighting device according to the first embodiment of the present disclosure,
The ratio of the dimension in the first direction and the dimension in the second direction of the cross section perpendicular to the optical axis of the coherent light from the shaping optical system toward the diffractive optical element is from 8:10. It may be between 10: 8.

In the lighting device according to the first embodiment of the present disclosure,
An outer diameter of an incident area on the diffractive optical element of coherent light incident on the diffractive optical element from the shaping optical system may be larger than 7.0 mm.

In the lighting device according to the first embodiment of the present disclosure,
The shaping optical system may further include a diffusion optical system that diffuses coherent light emitted from the coherent light source.

In the lighting device according to the first embodiment of the present disclosure,
The diffusion optical system may be formed by two or more optical elements.

In the lighting device according to the first embodiment of the present disclosure,
The second optical system may be formed by two or more optical elements.

The lighting device according to the second embodiment of the present disclosure includes:
A plurality of coherent light sources, each emitting coherent light,
A plurality of shaping optical systems that are provided corresponding to each of the plurality of coherent light sources and shape the coherent light emitted from the corresponding coherent light source,
A plurality of diffractive optical elements provided corresponding to each of the plurality of coherent light sources and the plurality of shaping optical systems, and diffracting the coherent light shaped by the corresponding shaping optical system and directing the coherent light toward the illuminated area, Prepare,
Each of the plurality of coherent light sources emits coherent light as diffused light having different diffusion angles in a first direction and a second direction orthogonal to each other,
Each of the plurality of shaping optical systems changes a diffusion angle of coherent light emitted from a corresponding coherent light source in at least one of the first direction and the second direction; and the first optical system A second optical system that collimates the coherent light whose diffusion angle has been adjusted by:
Each first optical system changes the diffusion angle of the coherent light emitted from the corresponding coherent light source in the first direction and the diffusion angle in the second direction at different magnifications.

In the lighting device according to the second embodiment of the present disclosure,
The plurality of coherent light sources emit coherent light beams having different radiant fluxes,
The incident area of the coherent light on the diffractive optical element corresponding to the coherent light source that emits the coherent light having the smallest radiant flux is on the diffractive optical element corresponding to the coherent light source that emits the coherent light having the largest radiant flux. May be smaller than the incident area of the coherent light in the above.

  According to the illumination device of the embodiment of the present disclosure, the shape of a cross section perpendicular to the optical axis of coherent light incident on a diffractive optical element can be adjusted.

FIG. 1 is a diagram for describing the first embodiment according to the present disclosure, and is a perspective view illustrating a lighting device. FIG. 2 is a perspective view showing a general semiconductor laser. FIG. 3 is a diagram showing a cross section along an optical axis and a first direction of a shaping optical system of the illumination device in FIG. 1. FIG. 4 is a diagram showing a cross section of the shaping optical system of FIG. 3 along the optical axis and the second direction. FIG. 5 is a perspective view showing a first optical system of the shaping optical system shown in FIGS. 3 and 4. FIG. 6 is a diagram corresponding to FIG. 3 and is a diagram illustrating a modified example of the shaping optical system. FIG. 7 is a view corresponding to FIG. 4 and shows a shaping optical system according to the modification shown in FIG. FIG. 8 is a view corresponding to FIG. 3 and is a view showing another modified example of the shaping optical system. FIG. 9 is a view corresponding to FIG. 4 and shows a shaping optical system according to another modification shown in FIG. FIG. 10 is a view corresponding to FIG. 3 and is a view showing still another modified example of the shaping optical system. FIG. 11 is a view corresponding to FIG. 4 and shows a shaping optical system according to still another modification shown in FIG. FIG. 12 is a diagram for describing the second embodiment according to the present disclosure, and is a perspective view illustrating a lighting device.

  Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. In the drawings attached to the present specification, for the sake of illustration and ease of understanding, the scale, the vertical / horizontal dimension ratio, and the like are appropriately changed and exaggerated from those of the actual product.

  Further, as used herein, the shapes and geometric conditions and their degrees are specified.For example, terms such as “parallel”, “orthogonal”, and “identical”, and values of length and angle are strictly defined. Without being limited to any meaning, it should be interpreted to include a range in which similar functions can be expected.

<First embodiment>
FIG. 1 is a perspective view schematically illustrating the entire configuration of the lighting device 10. FIG. 2 is a perspective view of a semiconductor laser generally used as a light source of the lighting device 10. The illumination device 10 illustrated in FIG. 1 illuminates an illumination target area Z. In the illustrated example, the illuminated area Z has a pattern imitating a human face, but is not limited to this. The illuminated area Z may be illuminated with an arbitrary pattern, for example, a line pattern or a pattern having a character shape. Such a lighting device can be used, for example, as a part of a stationary information display lamp. Further, the present invention can be applied to various moving objects, that is, automobiles, bicycles, ships, airplanes, trains, and the like. Then, such a lighting device can illuminate the ground, floor, water surface, wall surface, and the like, and can show the pattern around.

  As shown in FIG. 1, the illumination device 10 includes a light source device 15 that emits light, and a diffractive optical element 40 that diffracts the light from the light source device 15 and directs the light toward the illumination region Z. The light source device 15 includes a coherent light source 20 that emits coherent light, and a shaping optical system 30 that shapes the coherent light emitted from the coherent light source 20. In the example shown in FIG. 1, the shaping optical system 30 and the diffractive optical element 40 are arranged in this order along the optical path of the coherent light from the coherent light source 20, and act on the coherent light in this order.

  In the illustrated example, the coherent light source 20 is a laser light source. The laser light source 20 oscillates laser light as an example of coherent light. The laser light projected from the laser light source has excellent straightness and is suitable as light for illuminating the illuminated area Z with high accuracy.

  In particular, in the illustrated example, as shown in FIG. 2, the laser light source 20 is a semiconductor laser that emits laser light as diffused light having anisotropic diffusion angle. As shown in FIG. 2, the laser light emitted from the laser light source 20 is diffused in a first direction d1 along the stacking direction of the semiconductor stacked body 23 including the active layer 22 disposed between the electrodes 21 of the semiconductor laser. The angle θ1 is different from the diffusion angle θ2 in the second direction d2 perpendicular to the first direction d1. In the illustrated example, the diffusion angle θ1 in the first direction d1 is larger than the diffusion angle θ2 in the second direction d2.

  Next, the shaping optical system 30 will be described. The shaping optical system 30 shapes the laser light emitted from the laser light source 20. In other words, the shaping optical system 30 shapes the shape of the cross section orthogonal to the optical axis Lx of the laser light and the three-dimensional shape of the light beam of the laser light. In the illustrated example, the shaping optical system 30 widens the laser light emitted from the laser light source 20 and collimates the laser light so as to approach a parallel light flux.

  Here, as described above, the diffusion angle θ1 of the laser light emitted from the laser light source 20 in the first direction d1 is different from the diffusion angle θ2 in the second direction d2. When such light is directly expanded and emitted toward the diffractive optical element 40, the cross section of the laser light incident on the diffractive optical element 40 perpendicular to the optical axis Lx becomes elliptical. However, depending on the illumination device, it may be desirable that the cross section of the light incident on the diffractive optical element 40 has a shape such as a circle or a square with a small dimensional difference in the longitudinal direction and the lateral direction. As described above, the shape of the cross section of the laser light emitted from the light source 20 may not match the desired shape of the cross section of the laser light incident on the diffractive optical element 40 in some cases. In order to solve such a problem, the shaping optical system 30 described below is devised to adjust the shape of the cross section of the laser light emitted from the light source 20.

  Hereinafter, the shaping optical system 30 will be described in detail with reference to FIGS. FIG. 3 is a diagram illustrating a cross section of the shaping optical system 30 along the optical axis Lx and the first direction d1. FIG. 4 is a diagram showing a cross section along the optical axis Lx and the second direction d2 of the shaping optical system. FIG. 5 is a perspective view of the first optical system 31 included in the shaping optical system 30. FIGS. 6 and 7 are diagrams showing modified examples of the shaping optical system 30. FIG. FIG. 6 is a view corresponding to FIG. 3 and showing a cross section along the optical axis Lx and the first direction d1 of the shaping optical system 30 according to the modification. FIG. 7 is a view corresponding to FIG. 4 and showing a cross section of the shaping optical system according to the modification shown in FIG. 6 along the optical axis Lx and the second direction d2.

  As shown in FIGS. 3 and 4, the shaping optical system 30 includes a first optical system 31, a diffusion optical system 33, and a second optical system 32 in the order along the optical path of the laser light. The first optical system 31 changes the diffusion angle of the laser light in at least one of the first direction d1 and the second direction d2. Further, the first optical system 31 changes the diffusion angle θ1 in the first direction d1 and the diffusion angle θ2 in the second direction d2 at different magnifications. The diffusion optical system 33 diffuses the laser light whose diffusion angle has been adjusted by the first optical system 31, and widens the optical path width. The second optical system 32 collimates the laser light whose diffusion angles θ1 and θ2 have been adjusted by the first optical system 31.

  In the illustrated example, the first optical system 31 changes the diffusion angle of the laser light in both the first direction d1 and the second direction d2. The first optical system 31 includes a first angle adjusting element 311 that changes at least one of a diffusion angle θ1 of the laser light from the laser light source 20 in the first direction d1 and a diffusion angle θ2 of the second direction d2, and a first direction d1. And a second angle adjustment element 312 that changes at least the other of the diffusion angle θ1 and the diffusion angle θ2 in the second direction d2. In the example shown in FIGS. 1 to 5, the first angle adjusting element 311 acts on the laser light from the laser light source 20 so that the diffusion angle θ1 in the first direction d1 becomes smaller. In the example shown in FIG. 5, the first angle adjustment element 311 is a biconvex cylindrical lens linearly extending along the second direction d2. On the other hand, the second angle adjusting element 312 acts on the laser light from the laser light source 20 so that the diffusion angle θ2 in the second direction d2 increases. In the example shown in FIG. 5, the second angle adjustment element 312 is a biconcave cylindrical lens linearly extending along the first direction d1. That is, for a laser beam emitted from the coherent light source 20 and having a diffusion angle θ1 in the first direction d1 larger than the diffusion angle θ2 in the second direction d2, the first optical system 31 causes the first direction d1 of the coherent light to change. Is changed at a magnification smaller than the diffusion angle θ2 in the second direction d2. With such a first angle adjusting element 311 and a second angle adjusting element 312, the diffusion angle θ1 of the laser light emitted from the laser light source 20 in the first direction d1 and the diffusion angle θ2 in the second direction d2 are determined. The difference can be reduced. Then, the cross section perpendicular to the optical axis Lx of the laser light incident on the diffractive optical element 40 can be approximated to a circle having a small dimensional difference between the first direction d1 and the second direction d2. In particular, in the illustrated example, the first angle adjustment element 311 and the second angle adjustment element 312 of the first optical system 31 have a first angle adjustment element 311 and a second angle adjustment element 312 having a cross section perpendicular to the optical axis Lx of the laser light emitted from the first optical system 31. The diffusion angles θ1 and θ2 of the laser light are adjusted so that the ratio between the dimension in the direction d1 and the dimension in the second direction d2 is between 8:10 and 10: 8.

  Incidentally, the laser light emitted from the laser light source 20 is diffracted by the diffractive optical element 40 to illuminate the illuminated area Z. If the power density of the laser light incident on the diffractive optical element 40 on the diffractive optical element 40 is high, when the laser light diffracted by the diffractive optical element 40 is directly viewed, it may adversely affect human eyes. In order to reduce the power density of the laser light on the diffractive optical element 40, the outer diameter of the cross section perpendicular to the optical axis Lx of the laser light incident on the diffractive optical element 40 may be increased. Here, in order to make the outer diameter of the cross section of the laser beam incident on the diffractive optical element 40 sufficiently large, it is conceivable to arrange the second optical system 32 sufficiently away from the light source 20. However, in this case, the dimensions of the entire lighting device 10 increase.

  In consideration of such points, in the illustrated example, a device for reducing the size of the lighting device 10 while taking safety into consideration has been devised. Specifically, the shaping optical system 30 includes a diffusion optical system 33. The diffusion optical system 33 expands the laser light emitted from the laser light source 20. By disposing such a diffusion optical system 33 between the laser light source 20 and the second optical system 32 along the optical path from the laser light source 20 to the second optical system 32, the laser light source 20 and the second optical system 32 can be reduced. In the illustrated example, the diffusion optical system 33 is formed as a biconcave lens.

  Further, in the illustrated example, the diffusion optical system 33 is disposed between the first optical system 31 and the second optical system 32 along the optical path from the first optical system 31 to the second optical system 32. Therefore, the diffusion optical system 33 acts on the laser light whose diffusion angle has been adjusted by the first optical system 31 to increase the optical path width. By arranging the first optical system 31 so as to act on the laser light before being diffused by the diffusion optical system 33, the dimensions of the first optical system 31 (the first angle adjustment element 311 and the second angle adjustment element 312) are determined. ) Can be reduced. Thus, the size of the lighting device 10 can be reduced.

  In the diffusion optical system 33, the outer diameter of the incident area on the diffractive optical element 40 of the laser light incident on the diffractive optical element 40 is the size of the human pupil diameter in a general light place. The laser beam is expanded so as to be larger than 0 mm, more preferably larger than 7.5 mm. Thus, when the laser light diffracted by the diffractive optical element 40 is directly viewed, the adverse effect of the laser light on human eyes can be effectively suppressed.

  Next, the second optical system 32 will be described. The second optical system 32 is a collimator lens. The collimating lens 32 adjusts the diffusion angles θ1 and θ2 by the first optical system 31 and collimates the divergent light beam diffused by the diffusion optical system 33.

  Next, the diffractive optical element 40 will be described. The diffractive optical element 40 is an element that exerts a diffractive action on light emitted from the light source device 15. The illustrated diffractive optical element 40 diffracts the light from the light source device 15 and directs the light to the illumination area Z. Therefore, the illuminated area Z is illuminated by the diffracted light from the diffractive optical element 40.

  As an example, each diffractive optical element 40 is configured as a hologram recording medium on which an interference fringe pattern is recorded. By variously adjusting the interference fringe pattern, the traveling direction of light diffracted by each diffractive optical element 40, in other words, the traveling direction of light diffused by each diffractive optical element 40 can be controlled.

  The diffractive optical element 40 can be manufactured by using, for example, scattered light from a real scattering plate as object light. More specifically, when the hologram photosensitive material, which is the base of the diffractive optical element 40, is irradiated with reference light and object light composed of coherent light having coherence with each other, interference fringes due to the interference of these lights cause hologram photosensitive material. And the diffractive optical element 40 is manufactured. As the reference light, laser light that is coherent light is used, and as the object light, for example, scattered light from an inexpensively available isotropic scattering plate is used.

  By irradiating the laser light toward the diffractive optical element 40 so as to travel in the opposite direction along the optical path of the reference light used in producing the diffractive optical element 40, the object light used in producing the diffractive optical element 40 is A reproduced image of the scattering plate is generated at the position of the original scattering plate. If the scattering plate that is the source of the object light used in manufacturing the diffractive optical element 40 has uniform surface scattering, the reproduced image of the scattering plate obtained by the diffractive optical element 40 also has uniform surface illumination. The area where the reproduced image of the scattering plate is generated can be set as the illumination area Z.

  In addition, instead of forming the complex interference fringe pattern formed on the diffractive optical element 40 using the actual object light and the reference light, the wavelength and the incident direction of the planned reproduction illumination light, and the reproduction should be performed. It is possible to design using a computer based on the shape and position of the image. The thus obtained diffractive optical element 40 is also called a computer generated hologram (CGH). For example, when the illuminating device 10 is used to illuminate the illuminated area Z having a certain size on the ground or on the water surface, it is difficult to generate object light, and the computer-generated hologram is used as a diffractive optical element. Preferably, it is used as 40.

  Further, Fourier transform holograms having the same diffusion angle characteristic at each point on the diffractive optical element 40 may be formed by computer synthesis. Further, an optical member such as a lens may be provided downstream of the diffractive optical element 40 so that the diffracted light is adjusted so as to be incident on the entire illuminated area Z.

  As a specific form of the diffractive optical element 40, a volume hologram recording medium using a photopolymer may be used, or a volume hologram recording medium of a type that records using a photosensitive medium containing a silver salt material, A hologram recording medium of a relief type (emboss type) may be used. Further, the diffractive optical element 40 may be a transmission type or a reflection type.

  Next, the operation of the illumination device 10 having the above-described configuration will be described.

  The laser light emitted from the laser light source 20 first enters the shaping optical system 30. Here, the diffusion angle θ1 of the laser light incident on the shaping optical system 30 in the first direction d1 is larger than the diffusion angle θ2 in the second direction d2.

  The shaping optical system 30 adjusts the diffusion angle θ1 in the first direction d1 and the diffusion angle θ2 in the second direction d2 of the laser light emitted from the laser light source 20, and outputs the laser light having the adjusted diffusion angles θ1 and θ2. Expanding. That is, the shaping optical system 30 shapes the laser light such that the dimensional difference between the first direction d1 and the second direction d2 of the cross section orthogonal to the optical axis Lx approaches a small circle and the cross section widens. In the example shown in FIGS. 1 to 5, the shaping optical system 30 includes a first optical system 31 that changes the diffusion angles θ1 and θ2 of the laser light, a diffusion optical system 33 that widens the laser light, and a diffusion angle and a second optical system 32 that collimates the laser light whose θ1 and θ2 have been adjusted. In the first optical system 31, the diffusion angle θ1 of the laser light from the laser light source 20 in the first direction d1 is adjusted by the first angle adjustment element 311. The second angle adjusting element 312 adjusts the diffusion angle θ2 of the laser light from the laser light source 20 in the second direction d2. At this time, the first and second angle adjusting elements 311 and 312 change the diffusion angle θ1 in the first direction d1 and the diffusion angle θ2 in the second direction d2 at different magnifications. Specifically, the first angle adjustment element 311 acts on the laser light emitted from the laser light source 20 to adjust the diffusion angle θ1 in the first direction d1 to be small. The second angle adjusting element 312 acts on the laser beam from the laser light source 20 to adjust the diffusion angle θ2 in the second direction d2 to be large. Thereby, the difference between the diffusion angles θ1 and θ2 of the laser light in the first direction d1 and the second direction d2 decreases, and the cross section orthogonal to the optical axis Lx approaches a circle. Further, the diffusion optical system 33 diffuses the laser light whose diffusion angles θ1 and θ2 have been adjusted, and widens the optical path width. Further, the collimating lens 32 collimates the divergent light beam diffused by the diffusion optical system 33.

  Next, the laser light shaped by the shaping optical system 30 travels to the diffractive optical element 40. The diffractive optical element 40 records interference fringes corresponding to the center wavelength of the laser light emitted from the laser light source 20, and can diffract the laser light incident from a certain direction in a desired direction with high efficiency. In the illustrated example, each diffractive optical element 40 diffuses the entire illuminated area Z located on a horizontal plane pl such as the ground or a water surface.

  Note that various changes can be made to the first embodiment described above. Hereinafter, modified examples will be described with reference to the drawings. In the following description and the drawings used in the following description, portions that can be configured in the same manner as in the above-described embodiment will be denoted by the same reference numerals as those used for corresponding portions in the above-described embodiment, and will be described in duplicate. The description of the operation will be omitted.

  For example, the shaping optical system 30 illustrated in FIGS. 3 to 5 includes a first optical system 31 including a first angle adjustment element 311 and a second angle adjustment element 312, a diffusion optical system 33, a second optical system 32, , But is not limited to this. For example, the first optical system 31 includes only one of the first angle adjustment element 311 and the second angle adjustment element 312, and determines one of the diffusion angle θ1 in the first direction d1 and the diffusion angle θ2 in the second direction d2. It may be adjusted.

  In addition, as shown in FIGS. 6 and 7, other optical elements can be used as the first angle adjustment element 311. For example, the first angle adjusting element 311 may be a plano-convex cylindrical lens. In this case, the plano-convex cylindrical lens as the first angle adjusting element 311 extends linearly along the second direction d2, and is arranged such that the convex surface faces the side opposite to the light source 20. Also, the second angle adjustment element 312 may be configured by another optical element. For example, the second angle adjustment element 312 may be a plano-concave cylindrical lens. In this case, the plano-concave cylindrical lens extends linearly along the first direction d1, and is arranged such that the concave surface faces the side of the laser light source 20 or the side opposite to the laser light source 20. Also in this case, the first optical system 31 changes the diffusion angle θ1 of the laser light emitted from the coherent light source 20 in the first direction d1 at a magnification smaller than the diffusion angle θ2 in the second direction d2. Of course, the first angle adjustment element 311 and the second angle adjustment element 312 may be concave and convex cylindrical lenses.

  In addition, as shown in FIGS. 6 and 7, the diffusion optical system 33 may be configured by a plurality of optical elements. For example, the diffusion optical system 33 may be formed by a biconcave lens 331 and a plano-concave lens 332 arranged in order along the optical path of the laser light. By configuring the diffusion optical system 33 with a plurality of optical elements, the aberration of the diffusion optical system 33 can be reduced. Further, the second optical system 32 may also be configured by a plurality of optical elements. For example, the second optical system 32 may be configured by a concave-convex lens (meniscus lens) 321 and a plano-convex lens 322 arranged in order along the optical path of the laser light. By configuring the second optical system 32 with a plurality of optical elements, the aberration of the second optical system 32 can be reduced.

  As shown in FIGS. 8 and 9, the first angle adjusting element 311 acts to increase the diffusion angle θ1 of the laser light from the laser light source 20 in the first direction d1. Is also good. In this case, the first angle adjustment element 311 is, for example, a biconcave cylindrical lens, and is arranged so as to extend linearly along the second direction d2.

  In addition, by employing the first optical system 31 that expands the laser light in both the first direction d1 and the second direction d2 as shown in FIGS. 10 can be reduced in size. That is, the first angle adjusting element 311 and the second angle adjusting element 312 both act to expand the laser light, so that the cross section perpendicular to the optical axis Lx of the laser light emitted from the first optical system 31 can be effectively formed. Can be increased. As a result, the optical path length from the laser light source 20 to the diffractive optical element 40, which is necessary for ensuring the safety of the illumination device 10, that is, the outer diameter of the laser light incident area on the diffractive optical element 40 is sufficiently large. The required optical path length can be effectively shortened.

  Further, as shown in FIGS. 10 and 11, the first angle adjusting element 311 acts to change the diffusion angle θ2 of the laser light from the laser light source 20 in the second direction d2. Is also good. Further, the second angle adjusting element 312 acts to change both the diffusion angle θ1 in the first direction d1 and the diffusion angle θ2 in the second direction d2 with respect to the laser light from the laser light source 20. There may be. In this case, the second angle adjusting element 312 changes the diffusion angle θ1 in the first direction d1 and the diffusion angle θ2 in the second direction d2 at different magnifications with respect to the laser light from the laser light source 20. And may be changed at the same magnification.

  In the examples shown in FIGS. 10 and 11, the first angle adjusting element 311 acts on the laser light from the laser light source 20 so as to increase the diffusion angle θ2 in the second direction d2. The adjusting element 312 acts on the laser light from the laser light source 20 so as to increase both the diffusion angle θ1 in the first direction d1 and the diffusion angle θ2 in the second direction d2. In the examples shown in FIGS. 10 and 11, the first angle adjusting element 311 is a biconcave cylindrical lens extending linearly along the first direction, and the second angle adjusting element 312 is a biconcave lens. Of course, the first angle adjusting element 311 may be a plano-concave cylindrical lens, and the second angle adjusting element 312 may be a plano-concave lens. Further, the first angle adjusting element 311 may be a concave / convex cylindrical lens, and the second angle adjusting element 312 may be a concave / convex lens. Further, as described above, the second angle adjusting element 312 changes the diffusion angle θ1 in the first direction d1 and the diffusion angle θ2 in the second direction d2 with respect to the laser light from the laser light source 20 at different magnifications. Or may be changed at the same magnification. Therefore, the second angle adjustment element 312 has a different cross section along the first direction d1 (cross section shown in FIG. 10) passing through the optical axis and a cross section along the second direction d2 (cross section shown in FIG. 11). Or may be formed so as to be equal. Further, the first angle adjusting element 311 functions to change both the diffusion angle θ1 in the first direction d1 and the diffusion angle θ2 in the second direction d2 with respect to the laser light from the laser light source 20. Alternatively, the second angle adjusting element 312 may act to change the diffusion angle θ2 in the second direction d2.

  In the examples shown in FIGS. 10 and 11, the first optical system 31 acts so as to expand the laser light in both the first direction d1 and the second direction d2. Therefore, downsizing of the lighting device 10 can be achieved while ensuring safety. In particular, in the examples shown in FIGS. 10 and 11, both the first angle adjusting element 311 and the second angle adjusting element 312 increase the diffusion angle θ2 in the second direction d2, which is the smaller diffusion angle. Since the laser beam acts on the laser beam, the cross section of the laser beam emitted from the first optical system 31 perpendicular to the optical axis Lx can be more effectively enlarged. Therefore, the optical path length from the laser light source 20 to the diffractive optical element 40, which is necessary to ensure the safety of the illumination device 10, that is, the outer diameter of the laser light incident area on the diffractive optical element 40 is made sufficiently large. The required optical path length can be further effectively shortened.

  Of course, the first optical system 31 may be configured to change the diffusion angle of the laser light incident on the first optical system 31 so as to be small in both the first direction d1 and the second direction d2.

  In the first embodiment described above, the illumination device 10 includes a coherent light source 20 that emits coherent light, a shaping optical system 30 that shapes the coherent light emitted from the coherent light source 20, and a shaping optical system. A diffractive optical element 40 that diffracts the coherent light shaped by the system 30 and directs the coherent light toward the illumination target area Z. The coherent light source 20 emits coherent light as diffused light having different diffusion angles θ1 and θ2 in a first direction d1 and a second direction d2 orthogonal to each other. The shaping optical system 30 has a first optical system 31 that changes the diffusion angle of coherent light in at least one of the first direction d1 and the second direction d2, and diffusion angles θ1 and θ2 are adjusted by the first optical system 31. And a second optical system 32 that collimates the coherent light. The first optical system 31 changes the diffusion angle θ1 in the first direction d1 and the diffusion angle θ2 in the second direction d2 at different magnifications. In this illuminating device 10, the coherent light incident on the diffractive optical element 40 is changed by changing the diffusion angle θ1 of the light source light emitted from the light source 20 in the first direction d1 and the diffusion angle θ2 in the second direction d2 at different magnifications. The shape of the cross section perpendicular to the optical axis Lx of light can be adjusted.

  In particular, in the above-described first embodiment, the coherent light source 20 emits coherent light as diffused light in which the diffusion angle θ1 in the first direction d1 is larger than the diffusion angle θ2 in the second direction d2. The one optical system 31 changes the diffusion angle θ1 of the coherent light in the first direction d1 at a magnification smaller than the diffusion angle θ2 in the second direction d2. In this case, the shape of the cross section perpendicular to the optical axis Lx of the coherent light incident on the diffractive optical element 40 can be approximated to a shape such as a circle having a small dimensional difference between the first direction d1 and the second direction d2.

  In the first embodiment, the size of the cross section of the coherent light from the shaping optical system 30 toward the diffractive optical element 40 in the first direction d1 perpendicular to the optical axis Lx of the coherent light and the second direction The ratio to the dimension at d2 is between 8:10 and 10: 8.

  In the first embodiment, the outside diameter of the incident area on the diffractive optical element 40 of the coherent light incident on the diffractive optical element 40 from the shaping optical system 30 is larger than 7.0 mm. In this case, the power density of the coherent light incident on the diffractive optical element 40 becomes sufficiently low, and the safety of the illumination device 10 can be improved.

  In the above-described first embodiment, the shaping optical system 30 further includes a diffusion optical system 33 that diffuses coherent light emitted from the coherent light source 20. This makes it possible to more effectively reduce the size of the lighting device 10 while ensuring safety.

  In the first embodiment described above, the diffusion optical system 33 may be formed by two or more optical elements 331 and 332. In this case, the aberration of the diffusion optical system 33 can be reduced.

  Further, the second optical system 32 may be formed of two or more optical elements 321 and 322. In this case, the aberration of the second optical system 32 can be reduced.

<Second Embodiment>
Next, a second embodiment will be described with reference to FIG.

  Illumination device 100 shown in FIG. 12 differs from illumination device 10 shown in FIGS. 1 to 5 in that the light source device includes a plurality of coherent light sources that emit coherent light beams having different radiant fluxes. Another difference is that a plurality of shaping optical systems and diffractive optical elements are provided corresponding to each of the plurality of coherent light sources. Other configurations are substantially the same as those of the lighting device 10 shown in FIGS. In the following description and the drawings used in the following description, parts that can be configured in the same manner as the first embodiment shown in FIGS. 1 to 5 will be denoted by the same reference numerals used for corresponding parts in the first embodiment. The same reference numerals will be used, and redundant description will be omitted.

  In the following description, “radiation flux of laser light” does not mean the maximum radiation flux that can be emitted by a laser light source. In other words, the “radiation flux of laser light” here does not mean the capability of the laser light source. The term “radiation flux of laser light” as used herein means the radiation flux of laser light actually emitted from a laser light source whose output has been adjusted according to the illumination application.

  As described above, the light source device 115 has the plurality of laser light sources 20a, 20b, and 20c. The plurality of laser light sources 20a, 20b, and 20c may be provided independently, or may be a light source module in which the plurality of laser light sources 20a, 20b, and 20c are arranged on a common substrate. In the illustrated example, each of the plurality of laser light sources 20a, 20b, and 20c is the semiconductor laser shown in FIG. 2 and is coherent as diffused light having different diffusion angles in the first direction d1 and the second direction d2 orthogonal to each other. Emit light.

  The plurality of laser light sources 20a, 20b, and 20c emit laser beams having different radiation fluxes (unit: W). The plurality of laser light sources 20a, 20b, and 20c are, for example, a first laser light source 20a that oscillates light in a red emission wavelength range, a second laser light source 20b that oscillates light in a green emission wavelength range, and a blue laser light source 20b. A third laser light source 20c that oscillates light in the emission wavelength range. According to this example, it is possible to illuminate the illuminated area Z with illumination light of a desired color by superimposing three laser lights emitted from the plurality of laser light sources 20a, 20b, and 20c. By adjusting the radiant flux of the laser light emitted from the plurality of laser light sources 20a, 20b, and 20c, the color of the illumination light can be adjusted.

  However, the present invention is not limited to the above example, and the light source device 115 may include two laser light sources or four or more laser light sources having different emission wavelength ranges. Further, in order to increase the emission intensity, a plurality of laser light sources may be provided for each emission wavelength range.

  Next, the plurality of shaping optical systems 30a, 30b, 30c will be described. The plurality of shaping optical systems 30a, 30b, 30c are provided corresponding to each of the plurality of coherent light sources 20a, 20b, 20c. Each of the plurality of shaping optical systems 30a, 30b, 30c is configured similarly to the shaping optical system 30 shown in FIG. 1, and shapes the coherent light emitted from the corresponding coherent light sources 20a, 20b, 20c.

  Each of the plurality of shaping optical systems 30a, 30b, 30c changes the diffusion angle of the coherent light emitted from the corresponding coherent light source 20a, 20b, 20c in at least one of the first direction d1 and the second direction d2. The optical system includes optical systems 31a, 31b, and 31c, and second optical systems 32a, 32b, and 32c that collimate the coherent light whose diffusion angle is adjusted by the corresponding first optical systems 31a, 31b, and 31c. Each of the first optical systems 31a, 31b, 31c converts the diffusion angle θ1 of the coherent light emitted from the corresponding coherent light source 20a, 20b, 20c in the first direction d1 and the diffusion angle θ2 of the second direction d2 at different magnifications. change. Each of the first optical systems 31a, 31b, and 31c is configured similarly to the first optical system 31 shown in FIG. 5, and includes a first angle adjusting element 311 and a second angle adjusting element 312. Each of the plurality of shaping optical systems 30a, 30b, and 30c includes a diffusion optical system 33a, 33b, and 33c that diffuses coherent light emitted from the corresponding laser light source 20a, 20b, or 20c. Each of the diffusion optical systems 33a, 33b, and 33c has the same configuration as the diffusion optical system 33 shown in FIGS. Each of the plurality of second optical systems 32a, 32b, 33c is a collimating lens that collimates the laser light whose diffusion angle has been adjusted by the corresponding first optical system 31a, 31b, 31c. Each of the second optical systems 32a, 32b, and 33c has the same configuration as the second optical system 32 shown in FIGS.

  Next, the plurality of diffractive optical elements 40a, 40b, 40c will be described. The plurality of diffractive optical elements 40a, 40b, 40c are provided corresponding to the plurality of laser light sources 20a, 20b, 20c and the plurality of shaping optical systems 30a, 30b, 30c, respectively. The plurality of diffractive optical elements 40a, 40b, and 40c are configured similarly to the diffractive optical element 40 shown in FIG. 1, and diffract coherent light shaped by the corresponding shaping optical systems 30a, 30b, and 30c. According to this example, even when the laser light sources 20a, 20b, and 20c oscillate laser light in different wavelength ranges, each of the diffractive optical elements 40a, 40b, and 40c has a different wavelength range generated by the corresponding laser light. Laser light can be diffracted with high efficiency.

  Light emitted from each of the plurality of laser light sources 20a, 20b, and 20c is diffracted by the diffractive optical elements 40a, 40b, and 40c corresponding to each laser light source, and then illuminates an area that at least partially overlaps. In particular, in the illustrated example, the light emitted from each of the plurality of laser light sources 20a, 20b, and 20c is diffracted by the diffractive optical elements 40a, 40b, and 40c corresponding to each of the laser light sources, and then the same illumination area Z is obtained. Lighting. More precisely, the diffracted light diffracted by each of the diffractive optical elements 40a, 40b, and 40c illuminates only the entire illuminated area Z. The diffracted light from each of the diffractive optical elements 40a, 40b, and 40c illuminates only the entire illuminated area Z over the entire area, thereby reducing uneven brightness and uneven color in the illuminated area Z. It can be less noticeable.

  As described above, the radiant flux [unit: W] of the laser light emitted from the plurality of laser light sources 20a, 20b, 20c is different from each other. The shaping optical systems 30a, 30b, and 30c shown in FIG. 12 correspond to each other in order to reduce the power density of the laser beams having different radiant fluxes on the corresponding diffractive optical elements 40a, 40b, and 40c to the same extent. The laser light emitted from the laser light sources 20a, 20b, and 20c is widened to a size corresponding to the radiant flux of the laser light.

  Specifically, the shaping optical systems 30a, 30b, 30c are designed as follows. That is, of the plurality of laser light sources 20a, 20b, and 20c, the incident area of the laser light on the diffractive optical element corresponding to the laser light source that emits the laser light having the minimum radiation flux becomes the maximum radiation flux. The shaping optical systems 30a, 30b, and 30c are designed to be smaller than the incident area of the laser light on the diffractive optical element corresponding to the laser light source that emits the laser light.

  In the illustrated example, the radiant flux of the laser light in the red wavelength range emitted from the first laser light source 20a is the largest, and the radiant flux of the laser light in the blue wavelength range emitted from the third laser light source 20c. Is the smallest. Therefore, the incident area of the laser beam on the diffractive optical element 40c corresponding to the third laser light source 20c that oscillates the laser beam with the minimum radiant flux is the first laser that oscillates the laser beam with the maximum radiant flux. It is smaller than the incident area of the laser light on the diffractive optical element 40a corresponding to the light source 20a.

  In the illustrated example, the incident area on the diffractive optical element corresponding to one laser light source arbitrarily selected is a laser light having a radiant flux larger than the laser light emitted from the one laser light source. It is smaller than the incident area on the diffractive optical element corresponding to another laser light source to be emitted. That is, as the radiant flux of the laser beam becomes smaller, the incident area on the corresponding diffractive optical element becomes smaller. In other words, as the radiant flux of the laser beam increases, the incident area on the corresponding diffractive optical element increases.

  In the illustrated example, the radiant flux of the laser light emitted from the second laser light source 20b is smaller than the radiant flux of the laser light emitted from the first laser light source 20a, and the radiant flux of the laser light emitted from the third laser light source 20c. Is larger than. That is, the radiant flux of the laser light decreases in the order of the first laser light source 20a, the second laser light source 20b, and the third laser light source 20c. The incident area of the laser beam on each diffractive optical element is smaller in the order of the diffractive optical element 40a, the diffractive optical element 40b, and the diffractive optical element 40c.

For example, the radiation beam Wa of the laser light emitted from the first laser light source 20a, the radiation beam Wb of the laser light emitted from the second laser light source 20b, the radiation beam Wc of the laser light emitted from the third laser light source 20c, the diffractive optical element The area Aa of the incident area of the laser light on 40a, the area Ab of the incident area of the laser light on the diffractive optical element 40b, and the area Ac of the incident area of the laser light on the diffractive optical element 40c have the following relationship. By satisfying them, the power densities of the laser beams having different radiation fluxes on the corresponding diffractive optical elements 40a, 40b, and 40c can be made equal.
Wa: Wb: Wc = Aa: Ab: Ac
As one specific example, in the illustrated lighting device 100, the radiation flux Wa of the laser light emitted from the first laser light source 20a, the radiation flux Wb of the laser light emitted from the second laser light source 20b, and the emission flux from the third laser light source 20c. The radiant flux Wc of the emitted laser light has a relationship of 7: 5: 4. The area ratio of the incident area of the laser light on the diffractive optical element 40a, the diffractive optical element 40b, and the diffractive optical element 40c is 7: 5: 4.

  Further, in the example shown in FIG. 12, the area size of the incident surface and the outgoing surface of each of the diffractive optical elements 40a, 40b, and 40c is determined by the area of the incident area of the laser light on each of the diffractive optical elements 40a, 40b, and 40c. It depends on the size. Specifically, the area of the diffractive optical element 40c corresponding to the laser light source 20c that emits the laser beam having the minimum radiant flux is different from the area of the diffractive optical element 40c corresponding to the laser light source 20a that emits the laser light having the maximum radiant flux. It is smaller than the area of 40a. As described above, the incident area of the laser light on the diffractive optical element 40c is smaller than the incident area of the laser light on the diffractive optical element 40a. Therefore, the area of the entrance surface and the exit surface of the diffractive optical element 40c can be made smaller than the area of the entrance surface and the exit surface of the diffractive optical element 40a. Then, by reducing the area of the entrance surface and the exit surface of the diffractive optical element 40c, that is, by reducing the planar shape of the diffractive optical element 40c, it is possible to avoid unnecessary enlargement of the illumination device 100. The size can be reduced.

  Further, in the illustrated example, the area of the diffractive optical element corresponding to one laser light source arbitrarily selected is different from that of the other laser light emitting laser light having a radiant flux larger than the laser light emitted by the one laser light source. The area is set to be equal to or less than the area of the diffractive optical element corresponding to one laser light source. That is, as the radiant flux of the laser light source decreases, the area of the corresponding diffractive optical element decreases. In other words, as the radiant flux of the laser light source increases, the area of the corresponding diffractive optical element increases. In the illustrated example, the area of each diffractive optical element decreases in the order of the diffractive optical element 40a, the diffractive optical element 40b, and the diffractive optical element 40c. Thereby, the lighting device 100 can be effectively reduced in size.

  Next, the operation of the illumination device 100 having the above-described configuration will be described.

  The laser beams emitted from the plurality of laser light sources 20a, 20b, 20c first enter the corresponding shaping optical systems 30a, 30b, 30c. Here, the diffusion angle of the laser light incident on each of the shaping optical systems 30a, 30b, 30c in the first direction d1 is larger than the diffusion angle in the second direction d2. Further, the radiant fluxes of the laser light incident on the plurality of shaping optical systems 30a, 30b, 30c are different from each other.

  In each of the shaping optical systems 30a, 30b, and 30c, the diffusion angles of the laser light emitted from the corresponding laser light sources 20a, 20b, and 20c in the first direction d1 and the diffusion angle in the second direction d2 are adjusted. Enlarge the adjusted laser light. That is, the difference between the dimensions in the first direction d1 and the second direction d2 of the cross section orthogonal to the optical axis Lx of the laser light incident on each of the shaping optical systems 30a, 30b, 30c is reduced, and the cross section is widened. To shape the laser light. In the illustrated example, each of the shaping optical systems 30a, 30b, and 30c includes a diffusion optical system 33a, 33b, and 33c that widens the laser light, and a laser light whose diffusion angle is adjusted by the first optical systems 31a, 31b, and 31c. And a second optical system 32a, 32b, 32c for collimating the light. Then, the first angle adjusting element 311 of each of the first optical systems 31a, 31b, 31c acts on the laser light emitted from the corresponding laser light source 20a, 20b, 20c to reduce the diffusion angle in the first direction d1. Adjust so that Further, the second angle adjusting element 312 of each of the first optical systems 31a, 31b, 31c acts on the laser light from the corresponding laser light source 20a, 20b, 20c to increase the diffusion angle in the second direction d2. Adjust as follows. Thereby, the difference between the diffusion angles θ1 and θ2 of the laser light in the first direction d1 and the second direction d2 is reduced, and the difference between the dimensions of the cross section orthogonal to the optical axis Lx in the first direction d1 and the second direction d2 is reduced. Become smaller. Each of the diffusion optical systems 33a, 33b, and 33b diverges the laser light whose diffusion angles θ1 and θ2 are adjusted. Then, each of the collimating lenses 32a, 32b, 32c collimates the divergent light beam diffused by the corresponding diffusion optical system 33a, 33b, 33b so as to approach a parallel light beam.

  Each of the first optical systems 31a, 31b, and 31c and each of the diffusion optical systems 33a, 33b, and 33c are arranged such that the incident area of the laser light on the corresponding collimating lens 32a, 32b, or 32c is changed to the corresponding laser light source 20a or 20b. , 20c are shaped so as to have a size corresponding to the radiant flux of the laser beam emitted from the laser beam. For this reason, in the example shown in FIG. 12, the incident area of the laser beam on the collimator lens 32a is the largest, and the incident area of the laser beam on the collimator lens 32c is the smallest.

  The laser beam shaped by each shaping optical system 30a, 30b, 30c then travels to the corresponding diffractive optical element 40a, 40b, 40c. Each of the diffractive optical elements 40a, 40b, and 40c records interference fringes corresponding to the center wavelength of the laser light emitted from the corresponding laser light source 20a, 20b, or 20c. It can be diffracted in the direction with high efficiency. In the illustrated example, each of the diffractive optical elements 40a, 40b, and 40c diffuses the entire illuminated area Z located on a horizontal plane pl such as the ground or a water surface.

  In the above-described second embodiment described above, the lighting apparatus 100 includes a plurality of coherent light sources 20a, 20b, and 20c, each of which emits coherent light, and a plurality of coherent light sources 20a, 20b, and 20c. A plurality of shaping optical systems 30a, 30b, 30c provided correspondingly to shape coherent light emitted from the corresponding coherent light sources 20a, 20b, 20c, and a plurality of coherent light sources 20a, 20b, 20c and a plurality of shaping A plurality of diffractive optical elements 40a, which are provided corresponding to the respective optical systems 30a, 30b, 30c, diffract the coherent light shaped by the corresponding shaping optical systems 30a, 30b, 30c and direct the coherent light toward the illuminated area Z. 40b and 40c. Each of the plurality of coherent light sources 20a, 20b, and 20c emits coherent light as diffused light having different diffusion angles θ1 and θ2 in a first direction d1 and a second direction d2 orthogonal to each other, and a plurality of shaping optical systems 30a. , 30b, 30c change the diffusion angles θ1, θ2 of the coherent light emitted from the corresponding coherent light sources 20a, 20b, 20c in at least one of the first direction d1 and the second direction d2. , 31b, 31c, and a second optical system 32 that collimates the coherent light whose diffusion angles θ1, θ2 have been adjusted by the first optical systems 31a, 31b, 31c. Each of the first optical systems 31a, 31b, and 31c has a different diffusion angle θ1 in the first direction d1 and a different diffusion angle θ2 in the second direction d2 of the coherent light emitted from the corresponding coherent light sources 20a, 20b, and 20c. Change with magnification. In the illumination device 100, the diffractive optical element 40a is changed by changing the diffusion angle θ1 of the light source light emitted from the light sources 20a, 20b, and 20c in the first direction d1 and the diffusion angle θ2 of the second direction d2 at different magnifications. , 40b, 40c, the shape of the cross section perpendicular to the optical axis Lx of the coherent light incident thereon can be adjusted.

  In the above-described second embodiment, the plurality of coherent light sources 20a, 20b, and 20c emit coherent light beams having different radiation fluxes. Then, the incident area of the coherent light on the diffractive optical element 40c corresponding to the coherent light source 20c that emits the coherent light having the minimum radiant flux corresponds to the coherent light source 20a that emits the coherent light having the maximum radiant flux. Smaller than the incident area of the coherent light on the diffractive optical element 40a. In this case, by making the area of the diffractive optical element 40c smaller than the area of the diffractive optical element 40a, the illumination device 100 can be downsized.

  In the above, a plurality of embodiments and their modifications have been described. However, it is naturally possible to appropriately combine a plurality of configurations described as different embodiments and different modifications.

Reference Signs List 10 illumination device 15 light source device 20 coherent light source 30 shaping optical system 31 first optical system 32 second optical system 40 diffusion diffractive optical element Lx optical axis Z illuminated area

Claims (9)

A coherent light source that emits coherent light,
A shaping optical system for shaping coherent light emitted from the coherent light source,
A diffractive optical element that diffracts the coherent light shaped by the shaping optical system and directs it toward the illuminated area,
The coherent light source emits coherent light as diffused light having different diffusion angles in a first direction and a second direction orthogonal to each other,
The shaping optical system is configured to change a diffusion angle of the coherent light in at least one of the first direction and the second direction, and to collimate the coherent light whose diffusion angle is adjusted by the first optical system. A second optical system,
The illumination device, wherein the first optical system changes the diffusion angle in the first direction and the diffusion angle in the second direction at different magnifications. The coherent light source emits coherent light as diffusion light in which the diffusion angle in the first direction is larger than the diffusion angle in the second direction,
The lighting device according to claim 1, wherein the first optical system changes a diffusion angle of the coherent light in the first direction at a magnification smaller than a diffusion angle in the second direction.   The ratio of the dimension in the first direction and the dimension in the second direction of the cross section perpendicular to the optical axis of the coherent light from the shaping optical system toward the diffractive optical element is from 8:10. 3. The lighting device according to claim 2, wherein the lighting device is between 10: 8.   The illumination according to any one of claims 1 to 3, wherein an outer diameter of an incident area on the diffractive optical element of coherent light incident on the diffractive optical element from the shaping optical system is larger than 7.0 mm. apparatus.   The lighting device according to any one of claims 1 to 4, wherein the shaping optical system further includes a diffusion optical system that diffuses coherent light emitted from the coherent light source.   The lighting device according to claim 5, wherein the diffusion optical system is formed by two or more optical elements.   The lighting device according to claim 1, wherein the second optical system includes two or more optical elements. A plurality of coherent light sources, each emitting coherent light,
A plurality of shaping optical systems that are provided corresponding to each of the plurality of coherent light sources and shape the coherent light emitted from the corresponding coherent light source,
A plurality of diffractive optical elements provided corresponding to each of the plurality of coherent light sources and the plurality of shaping optical systems, and diffracting the coherent light shaped by the corresponding shaping optical system and directing the coherent light toward the illuminated area, Prepare,
Each of the plurality of coherent light sources emits coherent light as diffused light having different diffusion angles in a first direction and a second direction orthogonal to each other,
Each of the plurality of shaping optical systems changes a diffusion angle of coherent light emitted from a corresponding coherent light source in at least one of the first direction and the second direction; and the first optical system A second optical system that collimates the coherent light whose diffusion angle has been adjusted by:
An illumination device, wherein each first optical system changes the diffusion angle of the coherent light emitted from the corresponding coherent light source in the first direction and the diffusion angle in the second direction at different magnifications. The plurality of coherent light sources emit coherent light beams having different radiant fluxes,
The incident area of the coherent light on the diffractive optical element corresponding to the coherent light source that emits the coherent light having the smallest radiant flux is on the diffractive optical element corresponding to the coherent light source that emits the coherent light having the largest radiant flux. The illumination device according to claim 8, wherein the illumination region is smaller than an incident area of the coherent light at the point.

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