WO2019022078A1

WO2019022078A1 - Illumination device

Info

Publication number: WO2019022078A1
Application number: PCT/JP2018/027715
Authority: WO
Inventors: 牧夫倉重; 俊平西尾
Original assignee: 大日本印刷株式会社
Priority date: 2017-07-25
Filing date: 2018-07-24
Publication date: 2019-01-31
Also published as: JP7092086B2; JPWO2019022078A1; CN110869666B; CN110869666A; JP6508580B1; JP2019133950A

Abstract

An illumination device (10) comprises: a light source (15) that emits light; a diffraction optical element (40) that diffracts the light emitted from the light source (15); and a projection optical system (50) that reflects or refracts the light diffracted by the diffraction optical system (40) and directs such light to a projection surface S. The projection optical system (50) directs some rays of primary diffraction light diffracted by the diffraction optical element (40) and some other rays of the of primary diffraction light in different directions.

Description

Lighting device

The present disclosure relates to a lighting device.

For example, as disclosed in Patent Document 1, an illumination apparatus including a light source and a hologram element is known. In the vehicle lighting device disclosed in Patent Document 1, when the hologram element diffracts the light from the light source, it can project light in a specific direction to illuminate a projection surface such as a road surface.

JP 2012-146621

By the way, when illuminating using an illuminating device, it may be desired to project light to a plurality of directions and to perform a plurality of illuminations simultaneously. If light can be projected in a plurality of directions, for example, the projection plane can be divided into a plurality of regions by illuminating the projection plane with a plurality of linear patterns extending in a plurality of directions.

The embodiment of the present disclosure is made in consideration of the above points, and aims to provide a lighting device capable of projecting light in a plurality of directions.

A lighting device according to an embodiment of the present disclosure is
A light source for emitting light,
A diffractive optical element that diffracts the light emitted from the light source;
And a projection optical system that reflects or refracts the light diffracted by the diffractive optical element and directs it to a projection surface.
The projection optical system directs one part of the first-order diffracted light diffracted by the diffractive optical element and the other part in different directions.

In a lighting device according to an embodiment of the present disclosure,
The diffractive optical element includes: a first element diffractive optical element that diffracts a part of the light emitted from the light source; and a second element diffractive optical element that diffracts another part of the light emitted from the light source. Have
The projection optical system includes: first diffracted light which is first order diffracted light diffracted by the first element diffractive optical element; and second diffracted light which is first order diffracted light diffracted by the second element diffractive optical element; May be directed in different directions.

In the illumination device according to an embodiment of the present disclosure, the projection optical system may be a reflective element or a prism.

Further, in the illumination device according to the embodiment of the present disclosure, the projection optical system includes a half mirror that reflects a part of first-order diffracted light diffracted by the diffractive optical element and transmits another part; And a reflective element for reflecting another part of the transmitted first-order diffracted light.

Further, in the illumination device according to the embodiment of the present disclosure, the projection optical system may be a projection diffractive optical element that diffracts light diffracted by the diffractive optical element.

In addition, in the lighting device according to an embodiment of the present disclosure,
The diffractive optical element includes: a first element diffractive optical element that diffracts a part of the light emitted from the light source; and a second element diffractive optical element that diffracts another part of the light emitted from the light source. Have
The projection diffractive optical element is a first projection element diffractive optical element that diffracts first diffraction light, which is first-order diffraction light that is diffracted by the first element diffractive optical element, and directs the first diffraction light in a first direction; And a second projection element diffractive optical element for diffracting second diffracted light, which is first-order diffracted light diffracted by the two-element diffractive optical element, and directing it to a second direction different from the first direction; It is also good.

In addition, the illumination device according to an embodiment of the present disclosure may further include a collimator lens disposed between the light source along the optical path from the light source to the diffractive optical element and the diffractive optical element.

In the illumination device according to an embodiment of the present disclosure, the projection optical system changes the traveling direction of a part of first-order diffracted light diffracted by the diffractive optical element by an angle exceeding 90 °, and the diffractive optical system The traveling direction of another portion of the first-order diffracted light diffracted by the element may be changed at an angle of more than 90 °.

In addition, the lighting device according to an embodiment of the present disclosure may be housed in a tubular housing.

In this case, the housing may be rotatably disposed.

Also, the lighting device according to an embodiment of the present disclosure may be rotatably supported.

In addition, in the lighting device according to an embodiment of the present disclosure, the projection optical system may be rotatably supported.

In addition, in the illumination device according to the embodiment of the present disclosure, the diffractive optical element may be rotatably supported.

In addition, a lighting device according to an embodiment of the present disclosure is:
A first lens disposed between the diffractive optical element along the optical path from the diffractive optical element to the projection optical system and the projection optical system, wherein a focal distance of the first lens from the diffractive optical element A first lens spaced apart by
A second lens disposed between the first lens along the optical path from the first lens to the projection optical system and the projection optical system, wherein a focal distance of the first lens to the first lens And a second lens disposed spaced apart by the sum of the focal length of the second lens and the second lens,
A zero-order light mask disposed between the first lens and the second lens along the optical path from the first lens to the second lens, for blocking zero-order light in the diffractive optical element; It may further be provided.

In addition, a lighting device according to an embodiment of the present disclosure is:
A first lens disposed between the diffractive optical element along the optical path from the diffractive optical element to the projection optical system and the projection optical system, wherein a focal distance of the first lens from the diffractive optical element A first lens spaced apart by
A second lens disposed between the first lens along the optical path from the first lens to the projection optical system and the projection optical system, wherein a focal distance of the first lens to the first lens And a second lens disposed spaced apart by the sum of the focal length of the second lens and the second lens,
A high-order diffracted light mask disposed between the first lens and the second lens along the optical path from the first lens to the second lens, which blocks high-order diffracted light from the diffractive optical element; It may further be provided.

In addition, in the lighting device according to an embodiment of the present disclosure,
The projection optical system reflects or refracts a part and another part of the first-order diffracted light diffracted by the diffractive optical element, and directs them to a first illuminated area and a second illuminated area of the projection surface, respectively. ,
The first illuminated area and the second illuminated area may extend along a straight line as a whole. Furthermore, in this case, the first illuminated area and the second illuminated area may extend in a straight line.

According to the present disclosure, it is possible to provide a lighting device capable of projecting light in a plurality of directions.

FIG. 1 is a view for explaining a first embodiment according to the present disclosure, and is a perspective view showing a lighting device. FIG. 2: is a schematic diagram which shows an example of a structure of the illuminating device of FIG. FIG. 3 is a view for explaining a modification of the lighting device shown in FIG. 2, which is based on the length of the area illuminated by the lighting device shown in FIG. 2 and the lighting device projecting light in a single direction It is a figure which shows the length of the area | region to be illuminated. FIG. 4 is a view showing another modified example of the illumination device shown in FIG. FIG. 5 is a figure which shows the further another modification of the illuminating device shown in FIG. FIG. 6 is a figure which shows the further another modification of the illuminating device shown in FIG. FIG. 7 is a view showing still another modified example of the illumination device shown in FIG. FIG. 8 is a view corresponding to FIG. 2 and showing still another modification of the illumination device shown in FIG. FIG. 9 is a view showing a change of the illuminated area illuminated by the illumination device shown in FIG. 8, and a view of the illumination device and the projection plane shown in FIG. 8 from above. FIG. 10 is a view corresponding to FIG. 2 and showing still another modification of the illumination device shown in FIG. FIG. 11 is a view corresponding to FIG. 2 and showing still another modification of the illumination device shown in FIG. FIG. 12 is a diagram corresponding to FIG. 2, and is a schematic diagram illustrating an example of a configuration of a lighting device according to a second embodiment of the present disclosure.

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the drawings attached to the present specification, for the sake of easy illustration and understanding, the scale, the dimensional ratio in the vertical and horizontal directions, etc. are appropriately changed from those of the actual one and exaggerated.

In addition, as used herein, the terms such as “parallel”, “orthogonal”, “identical”, values of length and angle, etc., which specify the shape and geometric conditions and their degree, etc. It shall be interpreted including the range which can expect the same function without being restricted by the meaning.

First Embodiment
First, the first embodiment will be described with reference to FIGS. 1 and 2.

FIG. 1 is a perspective view showing an example of the illumination device 10 according to the first embodiment. FIG. 2: is a schematic diagram which shows an example of a structure of the illuminating device 10 shown in FIG.

As shown in FIG. 1, the illumination device 10 is installed on the ground or floor, and illuminates two different illumination areas Z1 and Z2 with the installation plane as a projection plane S. More specifically, the lighting apparatus 10 projects light in two different directions, and illuminates the first illuminated area Z1 and the second illuminated area Z2 in a linear pattern. Such an illumination device 10 can be used, for example, when partitioning the projection plane S. That is, the illuminating device 10 can show the boundary line of the area | region divided | segmented by line-shaped illumination area Z1, Z2. In addition, the illuminating device 10 may illuminate the to-be-illuminated area | regions Z1 and Z2 with arbitrary patterns other than a linear form, for example, may illuminate with the pattern of a figure or a character. Moreover, the illuminating device 10 may illuminate the to-be-illuminated area | regions Z1 and Z2 with a mutually different pattern.

As shown in FIG. 2, in the first embodiment, the illumination device 10 is diffracted by the light source 15 that emits light, the diffractive optical element 40 that diffracts the light emitted from the light source 15, and the diffractive optical element 40 And a projection optical system 50 for reflecting or refracting light and directing it to the projection surface S. Further, in the example shown in FIG. 2, the illumination device 10 further includes a shaping optical system 30 including a collimating lens 32 between the light source 15 and the diffractive optical element 40.

As understood from FIG. 1 and FIG. 2, the lighting device 10 is housed in a cylindrical housing 60 so as to be able to stand on the projection surface S. In the illustrated example, in the housing 60, the light source 15, the diffractive optical element 40, and the projection optical system 50 are aligned in a direction substantially perpendicular to the projection surface S. The housing 60 is provided with an opening 61 for transmitting light reflected or refracted by the projection optical system 50. Hereinafter, each component of the illuminating device 10 will be described in order.

The light source 15 can use various types of light sources. As an example, a light source emitting coherent light, for example, a laser light source can be used as the light source 15. The coherent light emitted from the light source 15 is excellent in straightness, and is suitable as light for illuminating the illumination regions Z1 and Z2 with high accuracy. In the example shown in FIG. 2, the lighting device 10 has a single light source 15, but may have a plurality of light sources 15.

Next, the shaping optical system 30 will be described. The shaping optical system 30 is disposed between the light source 15 along the optical path from the light source 15 to the diffractive optical element 40 and the diffractive optical element 40. The shaping optical system 30 shapes the light emitted from the light source 15. In other words, the shaping optical system 30 shapes the shape of the cross section orthogonal to the optical axis x of the light emitted from the light source 15 and the three-dimensional shape of the light flux of the light. In the illustrated example, the shaping optical system 30 shapes the light emitted from the light source 15 into a spread parallel light flux. As shown in FIG. 2, the shaping optical system 30 has a lens 31 and a collimating lens 32 in the order along the optical path of the light emitted from the light source 15. The lens 31 shapes the light emitted from the light source 15 into a divergent light beam. The collimating lens 32 reshapes the divergent light flux generated by the lens 31 into a parallel light flux. When the illumination device 10 has a plurality of light sources, a plurality of shaping optical systems may be provided corresponding to each of the plurality of light sources.

Next, the diffractive optical element 40 will be described. The diffractive optical element 40 is an element that exerts a diffractive action on the light emitted from the light source 15. The illustrated diffractive optical element 40 diffracts the light from the light source 15 and directs it to the projection optical system 50.

In the illustrated example, the diffractive optical element 40 includes a first element diffractive optical element 41 and a second element diffractive optical element 42. The first element diffractive optical element 41 diffracts a part of the light from the collimating lens 32 and directs it to the projection optical system 50. Further, the second element diffractive optical element 42 diffracts another part of the light from the collimating lens 32 and directs it to the projection optical system 50.

As an example, each element diffractive

optical element

41, 42 is configured as a hologram recording medium on which an interference fringe pattern is recorded. By adjusting the interference fringe pattern variously, the traveling direction of the light diffracted by each element diffractive

optical element

41, 42, in other words, the traveling direction of the light diffused by each element diffractive

optical element

41, 42, is controlled can do.

Each element diffractive

optical element

41 and 42 can be produced, for example, using scattered light from a real scattering plate as object light. More specifically, when the hologram photosensitive material that is the base of the element diffractive

optical elements

41 and 42 is irradiated with the reference light and the object light that are coherent light having interference with each other, interference fringes due to the interference of these lights are The element diffractive

optical elements

41 and 42 are manufactured by forming the hologram photosensitive material. As the reference light, laser light which is coherent light is used. As the object light, for example, scattered light from an isotropic scattering plate which can be obtained inexpensively is used.

The element diffractive

optical elements

41 and 42 are formed by irradiating the element diffractive

optical elements

41 and 42 with laser light so that the optical paths of the reference beams used when producing the element diffractive

optical elements

41 and 42 are reversed. A reproduction image of the scattering plate is generated at the arrangement position of the scattering plate which is the source of the object light used in fabrication. If the scattering plate which is the source of the object light used when producing the element diffractive

optical elements

41 and 42 performs uniform surface scattering, the reproduced image of the scattering plate obtained by the element diffractive

optical elements

41 and 42 Even, it will be a uniform surface illumination.

Also, instead of forming complex interference fringe patterns formed on the element diffractive

optical elements

41 and 42 using actual object light and reference light, the wavelength and incident direction of the planned reproduction illumination light, and reproduction, It is possible to design using a computer based on the shape, position, etc. of the image to be done. The element diffractive

optical elements

41 and 42 obtained in this manner are also called computer generated holograms (CGH).

In addition, Fourier transform holograms may be formed by computer synthesis in which diffusion angle characteristics at respective points on the element diffractive

optical elements

41 and 42 are the same.

A specific form of the element diffractive

optical elements

41 and 42 may be a volume type hologram recording medium using a photopolymer, or a volume type hologram recording medium of a type recording using a photosensitive medium containing a silver salt material. It may be a hologram recording medium of relief type (emboss type). The element diffractive

optical elements

41 and 42 may be transmissive or reflective.

When the illumination device 10 has a plurality of light sources, a plurality of diffractive optical elements may be provided corresponding to each of the plurality of light sources.

The projection optical system 50 reflects or refracts the light diffracted by the diffractive optical element 40 to direct it to the projection surface S (in the illustrated example, the installation surface). More specifically, the projection optical system 50 is diffracted by the first-order diffracted light (hereinafter also referred to as "first diffracted light") L11 diffracted by the first element diffractive optical element 41 and the second element diffractive optical element 42. The first-order diffracted light (hereinafter also referred to as “second diffracted light”) L12 is directed in different directions. In the element diffractive

optical elements

41 and 42 such as hologram elements, second-order or higher-order diffracted light (hereinafter also referred to as "high-order diffracted light") is a diffracted light as the diffracted light in addition to the first-order diffracted lights L11 and L12. It occurs. The projection optical system 50 directs at least first-order diffracted lights L11 and L12 of the diffracted lights entering the projection optical system 50 in directions different from each other.

In the illustrated example, the projection optical system 50 is a reflective element having a reflective surface that reflects light. The projection optical system 50 is made of a material having a high reflectance, such as metal, at least on its reflection surface. In particular, in the illustrated example, at least the reflection surface of the projection optical system 50 is made of silver and has a specular reflection function.

As described above, the projection optical system 50 has different directions of the first diffracted light L11 diffracted by the first element diffractive optical element 41 and the second diffracted light L12 diffracted by the second element diffractive optical element 42. Turn to. In the example shown in FIG. 2, the projection optical system 50 is configured as a so-called polygon mirror having a plurality of reflecting surfaces. More specifically, the projection optical system 50 has a triangular prism shape as a whole, and two of its three side surfaces form a reflecting surface. Then, one of the two reflecting surfaces is the first reflecting surface 51 on which the first diffracted light L11 is incident, and directs the first diffracted light L11 in the first direction. The other reflecting surface is the second reflecting surface 52 on which the second diffracted light L12 is incident, and directs the second diffracted light L12 in a second direction different from the first direction. In addition, as the projection optical system 50 capable of directing the first diffracted light L11 and the second diffracted light L12 in different directions, various types such as a concave mirror, a convex mirror, a plane mirror, a prism, etc. can be adopted besides the polygon mirror. It is.

In the example shown in FIG. 2, the direction of the first reflection surface 51 changes the traveling direction of the first diffracted light L11 at an angle exceeding 90 °, and the first diffracted light L11 is converted to the first object on the projection surface S. It is set to be directed to the illumination area Z1. In addition, the direction of the second reflection surface 52 changes the traveling direction of the second diffracted light L12 at an angle exceeding 90 °, and the second diffracted light L12 is directed to the second illumination region Z2 on the projection surface S. It is set to.

Next, the operation of the lighting device 10 configured as described above will be described.

The light emitted from the light source 15 first enters the shaping optical system 30. The shaping optical system 30 magnifies the light emitted from the light source 15. That is, the shaping optical system 30 shapes the light from the light source 15 so that the area occupied by the light is expanded in the cross section orthogonal to the optical axis x. In the illustrated example, the shaping optical system 30 includes a lens 31 and a collimating lens 32. As shown in FIG. 2, the lens 31 of the shaping optical system 30 diverges the light emitted from the light source 15 and converts it into a divergent light beam. Then, the collimating lens 32 of the shaping optical system 30 collimates the divergent light flux into a parallel light flux.

The light shaped by the shaping optical system 30 then travels to the diffractive optical element 40. The element diffractive

optical elements

41 and 42 of the diffractive optical element 40 record interference fringes corresponding to the central wavelength of the light emitted from the light source 15, and the light incident from a certain direction has high efficiency in the desired direction. It can be diffracted. In the illustrated example, the first element diffractive optical element 41 diffracts part of the light emitted from the light source 15 and diffuses the diffracted light toward the projection optical system 50. Also, the second element diffractive optical element 42 diffracts another part of the light emitted from the light source 15 and diffuses the diffracted light toward the projection optical system 50.

The light incident on the reflection surfaces 51 and 52 of the projection optical system 50 is reflected to change its traveling direction. In particular, the first diffracted light L11 incident on the first reflection surface 51 is reflected to change its traveling direction at an angle of more than 90 °. Then, the first diffracted light L11 reflected by the first reflection surface 51 passes through the opening 61 provided in the cylindrical casing 60, and is incident on the first illumination area Z1 on the projection surface S. In addition, the second diffracted light L12 incident on the second reflection surface 52 is reflected to change its traveling direction at an angle of more than 90 °. The second diffracted light L12 reflected by the second reflection surface 52 travels in a direction different from that of the first diffracted light L11 reflected by the first reflection surface 51. Then, the second diffracted light L12 passes through the opening 61 provided in the cylindrical casing 60, and is incident on the second illumination area Z2 different from the first illumination area Z1 on the projection surface S. In the illustrated example, the first illuminated area Z1 and the second illuminated area Z2 are illuminated in a line pattern extending in different directions from the illumination device 10.

According to the first embodiment as described above, the illumination device 10 includes the light source 15 for emitting light, the diffractive optical element 40 for diffracting the light emitted from the light source 15, and the light diffracted by the diffractive optical element 40. And a projection optical system 50 for reflecting or refracting the light toward the projection surface S. Then, the projection optical system 50 directs one portion L11 of the first-order diffracted light diffracted by the diffractive optical element 40 and the other portion L12 in different directions.

Such an illumination device 10 can project light in a plurality of directions to illuminate a plurality of illumination target areas Z1 and Z2.

In the first embodiment, the diffractive optical element 40 diffracts the first element diffractive optical element 41 that diffracts part of the light emitted from the light source 15 and the other part of the light emitted from the light source 15 And a second element diffractive optical element 42. Then, the projection optical system 50 includes a first diffracted light L11 which is a first-order diffracted light diffracted by the first element diffractive optical element 41 and a second diffracted light which is a first-order diffracted light diffracted by the second element diffractive optical element 42. The light L12 is directed in different directions. According to such an illumination device 10, it is easy to illuminate each of the plurality of illumination regions Z1 and Z2 with a desired pattern with high accuracy.

In the first embodiment, the projection optical system 50 is a reflective element or a prism. In this case, it is easy to realize the projection optical system 50 that reflects or refracts the first diffracted light L11 and the second diffracted light L12 and directs them in different directions.

Further, in the first embodiment, the collimator lens 32 disposed between the light source 15 along the optical path from the light source 15 to the diffractive optical element 40 and the diffractive optical element 40 is further provided. Thus, the collimated light is incident on the diffractive optical element 40, so that it is easy to diffract the first diffracted light L11 and the second diffracted light L12 in the desired direction with high accuracy by the diffractive optical element 40.

In the first embodiment, the projection optical system 50 changes the traveling direction of the part L11 of the first-order diffracted light diffracted by the diffractive optical element 40 by an angle exceeding 90 °, and the diffractive optical element 40 The traveling direction of the other part L12 of the diffracted first-order diffracted light is changed at an angle of more than 90 °. In this case, for example, as shown in FIG. 1 and FIG. 2, the illumination device 10 can illuminate the installation plane as the projection plane S.

Further, in the first embodiment, the lighting device 10 is accommodated in a cylindrical case 60. In this case, it is easy for the lighting device 10 to stand on the projection surface S. Furthermore, as shown in FIG. 4 described later, it is easy to install a part thereof in the ground, under the floor, or in water.

Note that various modifications can be made to the first embodiment described above. Hereinafter, some modifications will be described with reference to the drawings. In the following description and the drawings used in the following description, for the parts that can be configured in the same manner as the first embodiment described above, the same reference numerals as the reference numerals used for the corresponding parts in the first embodiment described above are used. It shall be used and the duplicate explanation is omitted.

<Modification 1>
In the first embodiment described above, for example, it is assumed that the illumination device 10 illuminates the first illuminated area Z1 and the second illuminated area Z2 extending in a straight line. In this case, in the illuminated areas Z1 and Z2, the closer to the illumination device 10, the clearer and brighter the pattern illumination becomes and the visibility is good. The farther the distance from the illumination device 10, the more the projection pattern is blurred and the darker illumination deteriorates the visibility. In consideration of this, the areas illuminated with good clarity and bright pattern (therefore clean) by the light L11 illuminating the illuminated area Z1 and the light L12 illuminating the illuminated area Z2 are respectively points E11 shown in FIG. From the point E12 to the point E22. Therefore, the lighting apparatus 10 can be used to illuminate a region of length L10 from the point E12 on one side of the lighting apparatus 10 to the point E22 on the other side in a clear and bright pattern with good visibility.

On the other hand, in the case of illuminating the illuminated area Z500 with the illumination device 500 that projects light only in a single direction using a light source that emits light of a radiation flux similar to the light source 15 of the illumination device 10, In the area Z500, the closer to the illumination device 500, the clearer and brighter the pattern illumination is, the visibility is good, and the projected pattern is more blurred and darker illumination as the distance from the illumination device 500 is smaller. The region illuminated with good visibility in a clear and bright pattern by the light L500 illuminating the light is a region of length L500 ranging from the point E51 to the point E52 shown in FIG.

Thus, the lighting device 10 can be used to illuminate a region of length L10 from the point E12 on one side of the lighting device 10 to the point E22 on the other side with a clear and bright pattern with good visibility. On the other hand, the illumination device 500 can illuminate with a clear and bright pattern with high visibility only in the region of length L500 extending from the point E51 on one side of the illumination device 500 to the point E52. In general, the length L10 is significantly longer than the length L500. That is, the illumination device 10 can be used to illuminate longer regions in a clear and bright pattern with high visibility as compared to the illumination device 500. In other words, in the case of illuminating a region having a length L10 longer than the above-mentioned length L500, if the lighting device 10 is disposed at the middle point of the region and light is projected from the middle point, the lighting device within the region It is possible to illuminate in a clear and bright pattern with good visibility to the points E12 and E22 farthest from 10.

In the description of the first modification described above, the illumination device 10 illuminates the first illuminated area Z1 and the second illuminated area Z2 extending in a straight line. However, the present invention is not limited to this. That is, the first illuminated area Z1 and the second illuminated area Z2 may not extend in a straight line. The first illuminated area Z1 and the second illuminated area Z2 may extend in directions crossing each other, for example, an area Z1b and an area Z2a shown in FIG. 9 described later. Even in this case, if the first illuminated area Z1 and the second illuminated area Z2 extend along a straight line as a whole, the first illuminated area Z1 and the second illuminated area Z2 extend in a straight line. The same effect as in the case of

According to the first modification as described above, the projection optical system 50 reflects or refracts a part L11 and a part L12 of the first-order diffracted light diffracted by the diffractive optical element 40 to form the projection surface S respectively. The light is directed to the first illuminated area Z1 and the second illuminated area Z2. The first illuminated area Z1 and the second illuminated area Z2 extend along a straight line as a whole. Particularly in the illustrated example, the first illuminated area Z1 and the second illuminated area Z2 extend in a straight line. In this case, the lighting device 10 can illuminate a region with a length L10 ranging from the point E12 on one side of the lighting device 10 to the point E22 on the other side with a clear and bright pattern with good visibility (therefore clean) However, with this length L10, the illumination device 500 that illuminates only a single direction with a light source that emits light of a radiant flux similar to that of the light source 15 of the illumination device 10 illuminates in a clear and bright pattern with good visibility It is significantly longer than the possible region length L500.

<Modification 2>
In the first embodiment described above, the case has been described in which the diffractive optical element 40 has the two element diffractive

optical elements

41 and 42 and the illumination device 10 illuminates the two illumination areas Z1 and Z2. It is not limited to. For example, as shown in FIG. 4, the diffractive optical element may have three or more element diffractive optical elements. In this case, the lighting device may project light in three or more directions to illuminate three or more illuminated areas.

The illuminating device 100 shown in FIG. 4 projects light in three directions to illuminate the three illumination regions Z1, Z2, and Z3. In the illumination device 100 shown in FIG. 4, the diffractive optical element 140 has three element diffractive

optical elements

41, 42 and 43, and the projection optical system 150 has three

reflective surfaces

51, 52 and 53. There is. The other configuration is substantially the same as the illumination device 10 shown in FIG. In FIG. 3, the casing 60 is omitted to facilitate understanding.

The diffractive optical element 140 has a third element diffractive optical element 43 in addition to the first element diffractive optical element 41 and the second element diffractive optical element 42. Similar to the other element diffractive

optical elements

41 and 42, the third element diffractive optical element 43 is configured as, for example, a hologram recording medium on which an interference fringe pattern is recorded. In the diffractive optical element 140 shown in FIG. 4, the first element diffractive optical element 41 diffracts part of the light from the collimator lens 32 and directs it to the projection optical system 150. In addition, the second element diffractive optical element 42 diffracts another part of the light and directs it to the projection optical system 150. In addition, the third element diffractive optical element 43 diffracts another portion of the light and directs it to the projection optical system 150.

The projection optical system 150 has a third reflection surface 53 in addition to the first reflection surface 51 and the second reflection surface 52. In the example shown in FIG. 4, the projection optical system 150 has a triangular pyramid shape. And three surfaces other than the bottom have a reflective function, and have constituted the

reflective surfaces

51, 52, and 53, respectively. The third reflection surface 53 is a first-order diffracted light (hereinafter also referred to as “third diffracted light”) L13 diffracted by the third element diffractive optical element 43, whichever of the first diffracted light L11 and the second diffracted light L12. Also turn in a different third direction. The third reflection surface 53 changes the traveling direction of the third diffracted light L13 at an angle exceeding 90 °, and directs the third diffracted light L13 to the third illuminated region Z3 on the projection surface S. . In addition, as a shape of the projection optical system 150, various shapes, such as conical shape, are employable besides pyramid shape.

<Modification 3>
In the first embodiment described above, the case where the illumination device 10 is installed on the projection surface S has been described. However, for example, when it is desired to make the illumination device 10 appear smaller, a portion of the illumination device 10 may be disposed below the projection surface S, ie, in the ground or floor, as shown in FIG. Moreover, when making a water surface into the projection surface S, the one part of the illuminating device 10 may be arrange | positioned in water.

<Modification 4>
In the first embodiment described above, the case where the lighting device 10 is installed on the ground or floor has been described, but is not limited thereto. The lighting device 10 can be used in various fields, for example, as a lighting device for moving objects such as cars and ships.

In the example illustrated in FIG. 6, the lighting device 10 is installed in the vehicle C, and projects light in two directions, the front lower right of the vehicle C and the front lower left of the vehicle C. Then, the lighting device 10 illuminates the first illuminated area Z1 located on the right front of the vehicle C and the second illuminated area Z2 located on the left front.

Further, in the example shown in FIG. 7, the lighting device 10 is installed in the vehicle C, and light is provided in two directions which are both in front of and below the vehicle C but have different angles with respect to the ground or floor which is the projection surface S. Project Then, the lighting device 10 illuminates the near-field illuminated region of the vehicle C and the far-field illuminated region.

The illumination device 10 shown in FIGS. 6 and 7 has a light source 15, a shaping optical system 30, a diffractive optical element 40 including a plurality of element diffractive optical elements, and projection optics, as in the illumination device described above. And a system 50. The projection optical system 50 is formed of a prism. This prism inclines with respect to the first prism surface 51a that changes the optical path of the first diffracted light L11 by refraction, and the first prism surface 51a, and refracts the optical path of the second diffracted light L12 by refracting the optical path of the first diffracted light L11. And a second prism surface 52a directed in a direction different from the light path.

<Modification 5>
Although the case where the projection optical system is the reflective element or the prism has been described in the first embodiment and the modification described above, the present invention is not limited to this. The projection optical system may be a projection diffractive optical element that exerts a diffractive action on the first-order diffracted light diffracted by the diffractive optical element 40.

Hereinafter, the fifth modification will be described with reference to FIG. The illumination device 200 shown in FIG. 8 differs from the illumination device 10 shown in FIG. 2 in that the projection optical system is a projection diffractive optical element 250.

As an example, the projection diffractive optical element 250 is configured as a hologram recording medium on which an interference fringe pattern is recorded. By adjusting the interference fringe pattern variously, it is possible to control the traveling direction of the light diffracted by the projection diffractive optical element 250, in other words, the traveling direction of the light diffused by the projection diffractive optical element 250. . The projection diffractive optical element 250 can be manufactured in the same manner as the element diffractive

optical elements

41 and 42 of the diffractive optical element 40.

In the example illustrated in FIG. 8, the projection diffractive optical element 250 includes a first projection diffraction region 251 on which the first diffracted light L11 that is first-order diffracted light diffracted by the first element diffractive optical element 41 is incident; And a second projection diffraction region 252 on which the second diffracted light L12 that is the first-order diffracted light diffracted by the element diffractive optical element 42 is incident. Then, the projection diffractive optical element 250 directs the first diffracted light L11 from the first element diffractive optical element 41 in a direction according to the diffraction characteristic of the first projection diffraction region 251. Further, the projection diffractive optical element 250 directs the second diffracted light L12 from the second element diffractive optical element 42 in a direction according to the diffraction characteristic of the second projection diffraction area 252.

In the illustrated example, the first projection diffraction region 251 diffracts the first diffracted light L11 from the first element diffractive optical element 41 and directs it to the first illuminated region Z1. Further, the second projection diffraction area 252 diffracts the second diffracted light L12 from the second element diffractive optical element 42 and directs it to the second illumination area Z2.

When such a projection diffractive optical element 250 is used as a projection optical system, the illuminated areas Z1 and Z2 illuminated by the illumination device 200 become areas according to the diffraction characteristics of the projection diffractive optical element 250. Therefore, by replacing the projection diffractive optical element 250 with another projection diffractive optical element having a diffraction characteristic different from that of the projection diffractive optical element 250, the illuminated regions Z1 and Z2 are illuminated by the illumination device 200. For example, the illumination areas Z1a and Z2a shown in FIG. 9 can be changed to illumination areas Z1b and Z2b.

As described above, according to the fifth modification, the projection optical system 250 is a projection diffractive optical element that diffracts the lights L11 and L12 diffracted by the diffractive optical element 40. As a result, by replacing the projection diffractive optical element 250 with another projection diffractive optical element having a diffraction characteristic different from that of the projection diffractive optical element 250, the illuminated area Z1, which is illuminated by the illumination device 200. Z2 can be changed.

<Modification 6>
In the fifth modification described above, the case where the portion of the first projection diffraction region 251 of the projection diffractive optical element 250 and the portion of the second projection diffraction region 252 are integrally formed has been described. It is not limited.

In the example shown in FIG. 10, the portion of the first projection diffraction region 251 of the projection diffractive optical element 250 and the portion of the second projection diffraction region 252 are configured separately. More specifically, the projection diffractive optical element 250 includes the first projection element diffractive optical element 253 on which the first-order diffracted light diffracted by the first element diffractive optical element 41 is incident, and the second element diffractive optical element 42. And a second projection element diffractive optical element 254 on which the diffracted first-order diffracted light is incident. The first projection element diffractive optical element 253 diffracts the first diffracted light L11, which is the first-order diffracted light from the first element diffractive optical element 41, and more specifically the first illuminated light in the first direction. Aim at area Z1. The second projection element diffractive optical element 254 diffracts the second diffracted light L12, which is the first-order diffracted light from the second element diffractive optical element 42, to a second direction different from the first direction. More specifically, the light is directed to the second illuminated area Z2.

When such a projection diffractive optical element 250 is used as a projection optical system, one of the first and second projection element diffractive optical elements 253 and 254 is different from the projection element diffractive optical elements 253 and 254. By replacing with another projection element diffractive optical element having diffraction characteristics, only one of the first and second illuminated areas Z1 and Z2 is switched from the illuminated area Z1a shown in FIG. 9 to the illuminated area Z1b, for example, Alternatively, the illumination area Z2a can be changed to the illumination area Z2b.

As described above, according to the sixth modification, the diffractive optical element 40 includes the first element diffractive optical element 41 that diffracts a part of the light emitted from the light source 15 and the other part of the light emitted from the light source 15 And a second element diffractive optical element 41 that diffracts. In addition, the projection diffractive optical element 250 diffracts the first diffracted light L11 which is the first-order diffracted light diffracted by the first element diffractive optical element 41 and directs it in the first direction. And a second projection element diffractive optical element 254 for diffracting the second diffracted light L12 which is the first order diffracted light diffracted by the second element diffractive optical element 42 and directing it to a second direction different from the first direction; Have. Thereby, any one of the first and second projection element diffractive optical elements 253 and 254 is replaced with another projection element diffractive optical element having diffraction characteristics different from those of the projection element diffractive optical elements 253 and 254. Thus, only one of the first and second illumination areas Z1 and Z2 can be changed.

<Modification 7>
Although the case where the diffractive optical element 40 includes a plurality of element diffractive optical elements has been described in the first embodiment and the first to sixth modifications described above, the present invention is not limited to this. The diffractive optical element 40 may be composed of a single element diffractive optical element.

Hereinafter, the seventh modification will be described with reference to FIG. The illumination device 300 shown in FIG. 11 is different from the illumination device shown in FIG. 2 in that the diffractive optical element 40 is configured of a single element diffractive optical element. Further, the projection optical system 350 is different in that it includes a half mirror 351 and a reflecting element 352.

In the example shown in FIG. 11, the diffractive optical element 40 diffracts all of the light emitted from the light source 15.

The half mirror 351 and the reflection element 352 of the projection optical system 350 are disposed on the optical path of the first-order diffracted light L1 diffracted by the diffractive optical element 40. The half mirror 351 is disposed between the diffractive optical element 40 and the reflective element 352 along the optical path from the diffractive optical element 40 to the reflective element 352.

The half mirror 351 reflects a portion L11 of the first-order diffracted light L1 diffracted by the diffractive optical element 340, directs it in the first direction, and transmits the other portion L12. The reflective element 352 reflects the other part L12 of the first order diffracted light L1 transmitted through the half mirror 351 and directs it in the second direction. In the illustrated example, the light L11 reflected by the half mirror 351 is directed to the first illuminated area Z1, and the light L12 reflected by the reflecting element 352 is directed to the second illuminated area Z2.

Also with such an illumination device 300, it is possible to direct the light emitted from the light source 15 in a plurality of directions to illuminate the plurality of illumination regions Z1 and Z2. In the illustrated example, the diffractive optical element 40 is configured of a single element diffractive optical element, but is not limited thereto. Similar to the example shown in FIG. 2, the diffractive optical element 40 may include a plurality of element diffractive

optical elements

41 and 42.

As described above, according to the seventh modification, the projection optical system 350 includes the half mirror 351 that reflects a part L11 of the first-order diffracted light L1 diffracted by the diffractive optical element 40 and transmits the other part L12. And a reflective element 352 for reflecting another portion L12 of the first-order diffracted light L1 transmitted through the mirror 351. In such an illumination device 300, the projection optical system 350 directs one portion L11 of the first-order diffracted light L1 diffracted by the diffractive optical element 40 and the other portion L12 in different directions. Therefore, the lighting device 300 can project light in a plurality of directions to illuminate the plurality of illumination target areas Z1 and Z2.

<Modification 8>
In the fifth and sixth modifications described above, the case where the illuminated regions Z1 and Z2 are moved by replacing part or all of the projection diffractive optical element 250 has been described, but the present invention is not limited thereto. For example, the housing 60 containing the

lighting devices

10, 100, 200, and 300 is rotatably disposed by mounting the housing 60 on a rotatable pedestal or the like, and the

lighting device

10, 100, 200, The illumination area may be moved by Z1, Z2, and Z3 by rotating along with 300. Alternatively, the

illumination devices

10, 100, 200, and 300 in the housing 60 are rotatably supported, and the

illumination devices

10, 100, 200, and 300 are rotated to move the illumination regions Z1, Z2, and Z3. May be Alternatively, the illumination regions Z1, Z2, and Z3 may be moved by rotatably supporting the diffractive

optical elements

40 and 140 and rotating the diffractive

optical elements

40 and 140. Alternatively, the projection

optical systems

50, 150, 250, and 350 may be rotatably supported, and the projection

optical systems

50, 150, 250, and 350 may be rotated to move the illumination regions Z1, Z2, and Z3. Alternatively, the diffractive

optical elements

40 and 140 and the projection

optical systems

50, 150, 250, and 350 are rotatably supported, and the projection

optical systems

50, 150, 250, and 350 are rotated together with the diffractive

optical elements

40 and 140. The illumination areas Z1, Z2, and Z3 may be moved.

Second Embodiment
Next, a second embodiment will be described with reference to FIG. In the following description and the drawings used in the following description, for the parts that can be configured in the same manner as the first embodiment described above, the same reference numerals as the reference numerals used for the corresponding parts in the first embodiment described above are used. It shall be used and the duplicate explanation is omitted.

First, in the illumination device shown in FIGS. 1 and 2, a part of light from the light source is transmitted through the diffractive optical element without being diffracted by the diffractive optical element, and becomes so-called zero-order light. If such zero-order light is reflected or refracted by the projection optical system, it may cause safety problems such as penetration into the eyes of the observer. In addition, when zero-order light is incident on the illuminated area, abnormal areas such as a dotted area, a linear area, and a planar area where the brightness (brightness) rises sharply compared to the surroundings are the illuminated area It will occur inside.

Further, as described above, in an element diffractive optical element such as a hologram element, second-order or higher-order diffracted light is generated as the diffracted light in addition to the first-order diffracted light. When the high-order diffracted light is reflected or refracted by the projection optical system, it may cause safety problems such as penetration into the eyes of the observer. In addition, when the high-order diffracted light is projected onto the projection plane, a region other than the region to be illuminated is also illuminated, which may cause problems such as difficulty in recognizing the region to be illuminated.

In order to solve such a problem, in the second embodiment, a device for preventing zero-order light and high-order diffracted light from being incident on the projection optical system is made. Hereinafter, with reference to FIG. 12, the illumination device 400 of the second embodiment will be described in more detail.

The illumination device 400 shown in FIG. 12 is different from the illumination device 10 shown in FIG. 1 in that the first lens 71, the second lens 72, the zeroth-order light mask 81, and the diffractive optical element 40 and the projection optical system 50. The only difference is that the high-order diffraction light mask 82 is disposed, and the other configuration is substantially the same as the illumination device 10 shown in FIGS. 1 and 2.

The first lens 71 and the second lens 72 are disposed between the diffractive optical element 40 and the projection optical system 50 along the optical path from the diffractive optical element 40 to the projection optical system 50. More specifically, the diffractive optical element 40, the projection optical system 50, the first lens 71, and the second lens 72 are disposed as follows.

The first lens 71 is separated between the diffractive optical element 40 and the projection optical system 50 along the optical path from the diffractive optical element 40 to the projection optical system 50 by the focal distance f1 of the first lens 71 from the diffractive optical element 40 It is arranged. The second lens 72 is disposed between the first lens 71 and the projection optical system 50 along the optical path from the first lens 71 to the projection optical system 50. The second lens 72 is spaced from the first lens 71 by the sum of the focal length f1 of the first lens 71 and the focal length f2 of the second lens 72. The distance between the second lens 72 and the projection optical system 50 is not particularly limited. In the example shown in FIG. 12, the second lens 72 is disposed apart from the incident position of the first diffracted light L11 and the second diffracted light L12 in the projection optical system 50 by the focal distance f2 of the second lens 72. The distance between the second lens 72 and the projection optical system 50 may be larger or smaller than the focal length f2. In the example shown in FIG. 12, the 4f optical system is formed by the first lens 71, the second lens 72, and the diffractive optical element 40.

The first lens 71 sets the zeroth-order light L01 transmitted through the first element diffractive optical element 41 and the zeroth-order light L02 transmitted through the second element diffractive optical element 42 to a point a on the focal plane P of the first lens 71. Turn. The first lens 71 also advances the 0th-order light L01 that has passed through the first lens 71 in the traveling direction of the first-order diffracted light (first diffracted light) L11 and the high-order diffracted light L21 of the first element diffractive optical element 41. Change the direction parallel to the direction. The first lens 71 also advances the 0th-order light L02 that has passed through the first lens 71 in the direction of travel of the first-order diffracted light (second diffracted light) L12 and the high-order diffracted light L22 at the second element diffractive optical element 42. Change the direction parallel to the direction. Thereby, as shown in FIG. 12, the incident positions of the zero-order light L01, L02, the first-order diffracted lights L11, L12 and the high-order diffracted lights L21, L22 on the focal plane P are the area around point a and point a, respectively. , It will be summarized in the outer region of the peripheral region.

The second lens 72 directs, to the projection optical system 50, light which has passed through a region between a zero-order light mask 81 and a high-order diffracted light mask 82 described later, that is, first diffracted light L11 and second diffracted light L12. Focus.

The zero-order light mask 81 is disposed between the first lens 71 and the second lens 72 along the optical path from the first lens 71 to the second lens 72. The zero-order light mask 81 is disposed on the focal plane P of the first lens 71 at a distance from the first lens 71 by the focal length f 1 of the first lens 71. The 0th-order light mask 81 overlaps with the position a of the focal plane P where the 0th-order light L01, L02 is incident, but is disposed at a position not overlapping with the 1st-order diffracted light L11, L12 and the high-order diffracted light L21, L22. Be done. As a result, the 0th-order light mask 81 can block only the 0th-order lights L01 and L02 among the diffracted lights in the diffractive optical element 40.

The high-order diffracted light mask 82 is also disposed on the same plane as the zero-order light mask 81. That is, the high-order diffraction light mask 82 is disposed between the first lens 71 and the second lens 72 along the optical path from the first lens 71 to the second lens 72. The high-order diffracted light mask 82 is disposed on the focal plane P of the first lens 71 at a distance from the first lens 71 by the focal length f 1 of the first lens 71. The high-order diffracted light mask 82 overlaps the position where the high-order diffracted light L21, L22 on the focal plane P is incident, but is disposed at a position not overlapping the position where the zero-order diffracted light L01, L02 and the first-order diffracted light L11, L12 are incident. Ru. As a result, the high-order diffracted light mask 82 can block only the high-order diffracted lights L21 and L22 among the diffracted lights in the diffractive optical element 40.

In the illustrated example, the zero-order light mask 81 and the high-order diffracted light mask 82 are plate-like members that absorb the zero-order lights L01 and L02 and the high-order diffracted lights L21 and L22, respectively. For example, the zero-order light mask 81 and the high-order diffracted light mask 82 may direct the zero-order lights L01 and L02 and the high-order diffracted lights L21 and L22 to other than the projection optical system 50, respectively.

Next, the operation of the illumination device 400 configured as described above will be described.

The light emitted from the light source 15 first enters the shaping optical system 30. The shaping optical system 30 magnifies the light emitted from the light source 15.

The light shaped by the shaping optical system 30 then travels to the diffractive optical element 40. The first element diffractive optical element 41 diffracts part of the light emitted from the light source 15. Further, the second element diffractive optical element 42 diffracts another part of the light emitted from the light source 15.

The light diffracted by the diffractive optical element 40 then travels to the first lens 71. Further, the zeroth-order lights L 01 and L 02 transmitted through the element diffractive

optical elements

41 and 42 also travel to the first lens 71. The first lens 71 directs zero-order light L01 and L02 to a point a on the focal plane P of the first lens 71. In the first lens 71, the first-order diffracted light L11 and the high-order diffracted light L21 from the first element diffractive optical element 41 are directed in a direction parallel to the traveling direction of the zero-order light L01. Further, in the first lens 71, the first-order diffracted light L12 and the high-order diffracted light L22 in the second element diffractive optical element 42 are directed in the direction parallel to the traveling direction of the zero-order light L02.

Of the light having passed through the first lens 71, zero-order light L 01 and L 02 are incident on the zero-order light mask 81. The high-order diffracted lights L21 and L22 enter the high-order diffracted light mask 82. On the other hand, the first-order diffracted lights (first and second diffracted lights) L11 and L12 pass through the region between the zero-order light mask 81 and the high-order diffracted light mask 82, and the second traveling direction is maintained. The light is incident on the lens 72.

The first diffracted light L11 and the second diffracted light L12 incident on the second lens 72 are condensed toward a point on the first reflection surface 51 of the projection optical system 50 and a point on the second reflection surface 52, respectively. .

The first diffracted light L11 incident on the first reflection surface 51 is reflected to change its traveling direction at an angle of more than 90 °. Then, the first diffracted light L11 reflected by the first reflection surface 51 passes through the opening 61 provided in the cylindrical casing 60, and is incident on the first illumination area Z1 on the projection surface S. In addition, the second diffracted light L12 incident on the second reflection surface 52 is reflected to change its traveling direction at an angle of more than 90 °. At this time, the second diffracted light L12 reflected by the second reflection surface 52 travels in a direction different from that of the first diffracted light L11 reflected by the first reflection surface 51. Then, the second diffracted light L12 reflected by the second reflection surface 52 passes through the opening 61 provided in the cylindrical casing 60, and the second diffracted light L12 is different from the first illumination area Z1 on the projection surface S. The light is incident on the illuminated area Z2.

According to the second embodiment as described above, the illumination device 400 is disposed between the diffractive optical element 40 and the projection optical system 50 along the optical path from the diffractive optical element 40 to the projection optical system 50. The first lens 71 is a single lens 71 and is separated from the diffractive optical element 40 by the focal length f1 of the first lens 71, and the first along the optical path from the first lens 71 to the projection optical system 50 The second lens 72 is disposed between the lens 71 and the projection optical system 50, and is separated from the first lens 71 by the sum of the focal length f1 of the first lens 71 and the focal length f2 of the second lens 72. And the second lens 72 disposed between the first lens 71 and the second lens 72 along the optical path from the first lens 71 to the second lens 72, and the zeroth-order light by the diffractive optical element 40 0th order to shut off L01 and L02 Further comprising a mask 81, a.

According to such an illumination device 400, it is possible to prevent the zeroth-order light L01 and L02 transmitted through the diffractive optical element 40 from being reflected or refracted by the projection optical system 50. As a result, the 0th-order light L01 and L02 enter the eyes of the observer and cause a safety problem, or the 0th-order light enters the area to be illuminated, and the brightness (brightness) is abrupt compared to the surroundings. The rising abnormal area is prevented from occurring in the illuminated area. In addition, since the first lens 71 is disposed apart from the diffractive optical element 40 by the above-described distance, zero-order light L01, L02, first-order diffracted light L11, L12 and high-order diffracted light L21, The path of L22 is adjusted, and it is easy to arrange the zero-order light mask 81 so as to block only the zero-order lights L01 and L02. Furthermore, since the second lens 72 is disposed apart from the first lens 71 by the above-described distance, the characteristics of the first diffracted light L11 and the second diffracted light L12 that have passed through the first lens 71 and the second lens 72 Can be determined according to the characteristics of the first diffracted light L11 and the second diffracted light L12 in the diffractive optical element 40. As a result, it is possible to illuminate the illuminated areas Z1 and Z2 with a desired pattern according to the diffraction characteristics of the diffractive optical element 40 (for example, the interference fringe pattern recorded in the element diffractive optical elements 41 and 42).

Further, according to the second embodiment as described above, the illumination device 400 is disposed between the diffractive optical element 40 and the projection optical system 50 along the optical path from the diffractive optical element 40 to the projection optical system 50. The first lens 71 is a first lens 71 disposed apart from the diffractive optical element 40 by the focal distance f1 of the first lens 71, and along the optical path from the first lens 71 to the projection optical system 50. The second lens 72 is disposed between the first lens 71 and the projection optical system 50, and is the sum of the focal distance f1 of the first lens 71 to the first lens 71 and the focal distance f2 of the second lens 72. It is disposed between the second lens 72 and the first lens 71 and the second lens 72 along the optical path from the first lens 71 to the second lens 72, and the height of the diffractive optical element 40 is high. Next-order diffracted light L21 and L22 And higher-order diffracted light mask 82, further comprising a.

According to such an illumination device 400, it is possible to prevent the high-order diffracted lights L21 and L22 in the diffractive optical element 40 from being reflected or refracted by the projection optical system 50. As a result, the high-order diffracted lights L21 and L22 enter the eyes of the observer and cause a safety problem, or the high-order diffracted lights L21 and L22 are projected on the projection surface S and the areas other than the illuminated areas Z1 and Z2 are also illuminated. As a result, it is possible to prevent the illumination regions Z1 and Z2 from being difficult to recognize. In addition, since the first lens 71 is disposed apart from the diffractive optical element 40 by the above-described distance, zero-order light L01, L02, first-order diffracted light L11, L12 and high-order diffracted light L21, The path of L22 is adjusted, and it is easy to arrange the high-order diffracted light mask 82 so as to block only the high-order diffracted lights L21 and L22. Furthermore, since the second lens 72 is disposed apart from the first lens 71 by the above-described distance, the characteristics of the first diffracted light L11 and the second diffracted light L12 that have passed through the first lens 71 and the second lens 72 Can be determined according to the characteristics of the first diffracted light L11 and the second diffracted light L12 in the diffractive optical element 40. As a result, it is possible to illuminate the illuminated areas Z1 and Z2 with a desired pattern according to the diffraction characteristics of the diffractive optical element 40 (for example, the interference fringe pattern recorded in the element diffractive optical elements 41 and 42).

In the above, although several embodiment and its modification were demonstrated, it is also possible to combine suitably the several structure demonstrated as a different embodiment and a different modification, of course.

Z1 First Illuminated Region Z2 Second Illuminated Region 10 Illumination Device 15 Light Source 32 Collimator Lens 40 Diffractive Optical Element 41 First Element Diffractive Optical Element 42 Second Element Diffractive Optical Element 50 Projection Optical System 51 First Reflective Surface 52 Second Reflecting surface 71 First lens 72 Second lens 81 0th order light mask 82 High order diffracted light mask

Claims

A light source for emitting light,
A diffractive optical element that diffracts the light emitted from the light source;
And a projection optical system that reflects or refracts the light diffracted by the diffractive optical element and directs it to a projection surface.
The projection optical system directs a part of first-order diffracted light diffracted by the diffractive optical element in a different direction from another part.
The diffractive optical element includes: a first element diffractive optical element that diffracts a part of the light emitted from the light source; and a second element diffractive optical element that diffracts another part of the light emitted from the light source. Have
The projection optical system includes: first diffracted light which is first order diffracted light diffracted by the first element diffractive optical element; and second diffracted light which is first order diffracted light diffracted by the second element diffractive optical element; The lighting device according to claim 1, wherein the light sources are directed in different directions.
The illumination device according to claim 1, wherein the projection optical system is a reflective element or a prism.
The projection optical system includes a half mirror that reflects a part of the first-order diffracted light diffracted by the diffractive optical element and transmits another part, and the other part of the first-order diffracted light transmitted through the half mirror. And a reflective element that reflects light.
The illumination device according to claim 1, wherein the projection optical system is a projection diffractive optical element that diffracts the light diffracted by the diffractive optical element.
The diffractive optical element includes: a first element diffractive optical element that diffracts a part of the light emitted from the light source; and a second element diffractive optical element that diffracts another part of the light emitted from the light source. Have
The projection diffractive optical element is a first projection element diffractive optical element that diffracts first diffraction light, which is first-order diffraction light that is diffracted by the first element diffractive optical element, and directs the first diffraction light in a first direction; A second projection element diffractive optical element for diffracting second diffracted light, which is first-order diffracted light diffracted by the two-element diffractive optical element, and directing it to a second direction different from the first direction; The lighting device according to 5.
The illumination device according to any one of claims 1 to 6, further comprising: a collimating lens disposed between the light source and the diffractive optical element along the optical path from the light source to the diffractive optical element.
The projection optical system changes the traveling direction of a part of the first-order diffracted light diffracted by the diffractive optical element by an angle exceeding 90 °, and another one of the first-order diffracted light diffracted by the diffractive optical element The lighting device according to any one of claims 1 to 7, wherein the traveling direction of the part is changed at an angle of more than 90 °.
The lighting device according to any one of claims 1 to 8, wherein the lighting device is housed in a cylindrical casing.
The lighting device according to claim 9, wherein the housing is rotatably disposed.
The lighting device according to any one of claims 1 to 10, which is rotatably supported.
The lighting device according to any one of claims 1 to 11, wherein the projection optical system is rotatably supported.
The illumination device according to any one of claims 1 to 12, wherein the diffractive optical element is rotatably supported.
A first lens disposed between the diffractive optical element along the optical path from the diffractive optical element to the projection optical system and the projection optical system, wherein a focal distance of the first lens from the diffractive optical element A first lens spaced apart by
A second lens disposed between the first lens along the optical path from the first lens to the projection optical system and the projection optical system, wherein a focal distance of the first lens to the first lens And a second lens disposed spaced apart by the sum of the focal length of the second lens and the second lens,
A zero-order light mask disposed between the first lens and the second lens along the optical path from the first lens to the second lens, for blocking zero-order light in the diffractive optical element; The lighting device according to any one of claims 1 to 13, further comprising:
A first lens disposed between the diffractive optical element along the optical path from the diffractive optical element to the projection optical system and the projection optical system, wherein a focal distance of the first lens from the diffractive optical element A first lens spaced apart by
A second lens disposed between the first lens along the optical path from the first lens to the projection optical system and the projection optical system, wherein a focal distance of the first lens to the first lens And a second lens disposed spaced apart by the sum of the focal length of the second lens and the second lens,
A high-order diffracted light mask disposed between the first lens and the second lens along the optical path from the first lens to the second lens, which blocks high-order diffracted light from the diffractive optical element; The lighting device according to any one of claims 1 to 14, further comprising:
The projection optical system reflects or refracts a part and another part of the first-order diffracted light diffracted by the diffractive optical element, and directs them to a first illuminated area and a second illuminated area of the projection surface, respectively. ,
The lighting device according to any one of claims 1 to 15, wherein the first illuminated area and the second illuminated area extend along a straight line as a whole.