WO2017145972A1

WO2017145972A1 - Lighting device

Info

Publication number: WO2017145972A1
Application number: PCT/JP2017/006068
Authority: WO
Inventors: 俊平西尾; 牧夫倉重
Original assignee: 大日本印刷株式会社
Priority date: 2016-02-24
Filing date: 2017-02-20
Publication date: 2017-08-31

Abstract

[Problem] To provide a lighting device capable of safely lighting an area to be lighted having a first direction while making the edges thereof distinct. [Solution] A lighting device (10) for lighting an area to be lighted extending in a first direction and extending in a second direction perpendicular to the first direction is provided with a light source, a diffraction optical element comprising a first hologram element and a second hologram element for diffracting light from the light source toward the area to be lighted, wherein the diffracted light in the first hologram element lights the entirety of the area to be lighted and the diffracted light in the second hologram element lights the entirety of the area to be lighted.

Description

Lighting device

The present disclosure relates to an illumination device that illuminates an illuminated area having a longitudinal direction.

For example, as disclosed in JP2015-132707A, an illumination device including a light source and a hologram element is known. In the illumination device disclosed in JP2015-132707A, the hologram element can illuminate the road surface with a desired pattern by diffracting light from the light source. In the illumination device disclosed in JP2015-132707A, a laser beam generated by a single light source is diffracted by a single hologram element.

However, JP2015-132707A does not discuss a device for preventing the area to be illuminated, that is, the edge of the illuminated area from becoming blurred. The sharpness of the edge of the illuminated area is more noticeable when illuminating the illuminated area having a longitudinal direction, particularly when illuminating a line-shaped illuminated area. In addition, when the illuminated area is illuminated using a plurality of light sources in the same wavelength range or different wavelength ranges, the edge of the illuminated area tends to become more blurred.

Furthermore, when a light source that emits laser light is used, the illuminated area can be illuminated brightly. However, on the other hand, when the illumination light from the illuminating device is directly viewed, there is a possibility of adversely affecting human eyes.

The present disclosure has been made in consideration of the above points, and an object of the present disclosure is to provide an illumination device that can safely illuminate an illuminated region having a longitudinal direction while sharpening the edge thereof. To do.

One aspect of the present disclosure is an illumination device that illuminates an illuminated region that extends in a first direction and extends in a second direction that intersects the first direction.
A light source;
A diffractive optical element having a first hologram element and a second hologram element for diffracting light from the light source and directing the light toward the illuminated region,
There is provided an illuminating device in which diffracted light from the first hologram element illuminates the entire area of the illuminated area and diffracted light from the second hologram element illuminates the entire area of the illuminated area.

The irradiation width along the second direction intersecting the first direction of the diffracted light from the first hologram element that enters the arbitrary position along the first direction of the illuminated area is the width of the illuminated area. The irradiation width along the second direction of the diffracted light from the second hologram element incident on the arbitrary position along the first direction may be the same.

The irradiation length along the first direction of the diffracted light from the first hologram element incident on an arbitrary position along the second direction intersecting the first direction of the illuminated area is the illumination area. The irradiation length along the first direction of the diffracted light from the second hologram element incident on the arbitrary position along the second direction may be the same.

In another aspect of the present disclosure, the illumination device illuminates an illuminated area that extends in a first direction and extends in a second direction that intersects the first direction.
A light source;
A diffractive optical element having a first hologram element and a second hologram element for diffracting light from the light source and directing the light toward the illuminated region,
In at least one of the first direction and the second direction of the illuminated area, the illumination range of the diffracted light from the first hologram element is aligned with the illumination range of the diffracted light from the second hologram element. A lighting device is provided.

The first hologram element and the second hologram element are arranged in a direction intersecting a first direction of the illuminated area and a direction intersecting a normal direction to a surface on which the illuminated area is formed. Has been
The irradiation width along the second direction intersecting the first direction of the diffracted light from the first hologram element that enters the arbitrary position along the first direction of the illuminated area is the width of the illuminated area. The irradiation width along the second direction of the diffracted light from the second hologram element incident on the arbitrary position along the first direction may be the same.

The first hologram element and the second hologram element are arranged in a direction intersecting a first direction of the illuminated area and along a normal direction to a surface on which the illuminated area is formed. Has been
The irradiation length along the first direction of the diffracted light from the first hologram element incident on an arbitrary position along the second direction intersecting the first direction of the illuminated area is the illumination area. The irradiation length along the first direction of the diffracted light from the second hologram element that enters the arbitrary position along the second direction is the same as
The irradiation width along the second direction of the diffracted light from the first hologram element incident on an arbitrary position along the first direction of the illuminated area is along the first direction of the illuminated area. Further, the irradiation width along the second direction of the diffracted light from the second hologram element incident on the arbitrary position may be the same.

The first hologram element includes a plurality of element holograms,
Diffracted light from at least two element holograms among the plurality of element holograms may illuminate the entire area to be illuminated.

The second hologram element includes a plurality of element holograms,
Diffracted light from at least two element holograms among the plurality of element holograms may illuminate the entire area to be illuminated.

The irradiation width along the second direction intersecting the first direction of diffracted light from one element hologram incident on an arbitrary position along the first direction of the illuminated region is the irradiation width of the illuminated region. It may be the same as the irradiation width along the second direction of the diffracted light from one other element hologram incident on the arbitrary position along the first direction.

The irradiation length along the first direction of the diffracted light from one element hologram incident on an arbitrary position along the second direction intersecting the first direction of the illuminated area is the length of the illuminated area. It may be the same as the irradiation length along the first direction of the diffracted light from one other element hologram element incident on the arbitrary position along the second direction.

The plurality of element holograms are arranged in a direction intersecting a first direction of the illuminated area and a direction intersecting a normal direction to a surface on which the illuminated area is formed,
The irradiation width along the second direction intersecting the first direction of diffracted light from one element hologram incident on an arbitrary position along the first direction of the illuminated region is the irradiation width of the illuminated region. It may be the same as the irradiation width along the second direction of the diffracted light from one other element hologram incident on the arbitrary position along the first direction.

The plurality of element holograms are arranged in a direction intersecting a first direction of the illuminated area and along a normal direction to a surface on which the illuminated area is formed,
The irradiation length along the first direction of the diffracted light from one element hologram incident on an arbitrary position along the second direction intersecting the first direction of the illuminated area is the length of the illuminated area. The irradiation length along the first direction of the diffracted light from the other one element hologram incident on the arbitrary position along the second direction is the same,
The irradiation width along the second direction of the diffracted light from the one element hologram incident on an arbitrary position along the first direction of the illuminated area is along the first direction of the illuminated area. Further, the irradiation width along the second direction of the diffracted light from the other one element hologram incident on the arbitrary position may be the same.

The light source includes a first coherent light source and a second coherent light source,
A first shaping optical system that shapes light from the first coherent light source and directs the light toward the first hologram element, and a second shaping optical system that shapes light from the second coherent light source and directs the light to the second hologram element And may be further provided.

In another aspect of the present disclosure, there is provided an illumination device that illuminates an illuminated area having a first direction,
A light source;
A diffractive optical element having a hologram element that diffracts light from the light source and directs it to the illuminated area, and
The hologram element includes a plurality of element holograms,
An illuminating device is provided in which diffracted light from at least two element holograms among the plurality of element holograms illuminates the entire area to be illuminated.

The light source includes a light emitting unit having a major axis direction and a minor axis direction intersecting the major axis direction,
There may be further provided a shaping optical system for shaping the light spreading from the light emitting portion in the minor axis direction so as to spread in the second direction intersecting the first direction by the hologram element.

In another aspect of the present disclosure, there is provided an illumination device that illuminates an illuminated area having a first direction, the light emitting unit having a major axis direction and a minor axis direction intersecting the major axis direction and emitting coherent light. Including a light source;
A diffractive optical element having a hologram element that diffracts coherent light from the light source and directs it to the illuminated area, and
There is provided an illuminating device in which coherent light spreading in the minor axis direction from the light emitting unit is shaped by the hologram element so as to spread in a second direction intersecting the first direction.

A shaping optical system that shapes the coherent light from the light source and directs it to the hologram element,
The coherent light spreading in the minor axis direction from the light emitting unit may be shaped so as to spread in the second direction by the hologram element after being shaped by the shaping optical system.

The shaping optical system may include a collimating lens that shapes coherent light from the light source into parallel light.

The minor axis direction may be parallel to the second direction.

The diffractive optical element has a center line extending in the first direction through a center position in a second direction intersecting the first direction of the illuminated area, and the first line passing through a center position of the diffractive optical element. The illuminated area may be illuminated so as to deviate from a projection line obtained by projecting an illumination light beam extending in the direction onto the illuminated area.

The light emitted from the light source is coherent light,
The diffractive optical element is configured such that, of the coherent light incident on the diffractive optical element, zero-order light that has not been diffracted by the diffractive optical element and passes through the diffractive optical element is the first direction of the illuminated region. The illuminated area may be illuminated so that it is incident on the farthest end side than the nearest end.

The light emitted from the light source and incident on the diffractive optical element may be diffused light that spreads more than parallel light.

According to the present disclosure, it is possible to safely illuminate the illuminated area having the longitudinal direction while clearing the edge.

FIG. 1 is a perspective view illustrating a lighting device for explaining an embodiment according to the present disclosure. FIG. 2 is a diagram for explaining diffraction characteristics of the hologram element of the illumination device of FIG. FIG. 2 shows the hologram element from the longitudinal direction of the illuminated area. FIG. 3 is a diagram for explaining diffraction characteristics of element holograms included in the hologram element of the illumination device of FIG. FIG. 3 shows the hologram element from the longitudinal direction of the illuminated area. FIG. 4 is a diagram for explaining a method of adjusting the diffraction characteristics of the hologram element and the element hologram. FIG. 5 is a diagram for explaining a method of adjusting the diffraction characteristics of the hologram element and the element hologram. FIG. 6 is a perspective view corresponding to FIG. 1 for explaining a modification of the lighting device. FIG. 7 is a diagram for explaining the relationship between the arrangement of a plurality of holograms having the same diffraction characteristics and the illumination area. FIG. 8 is a diagram for explaining the relationship between the arrangement of a plurality of holograms having the same diffraction characteristics and the illumination area. FIG. 9 is a diagram for explaining a modification of the lighting device. The figure which shows the example which the centerline of the to-be-illuminated area | region and the projection line have shifted | deviated. The perspective view of the illuminating device which has a reflection type hologram element.

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.

In addition, as used in this specification, the shape and geometric conditions and the degree thereof are specified. For example, terms such as “parallel”, “orthogonal”, “identical”, length and angle values, etc. are strictly Without being bound by any meaning, it should be interpreted including the extent to which similar functions can be expected.

FIG. 1 is a perspective view schematically showing the overall configuration of the lighting device 10. The illuminating device 10 illuminates the illuminated area Z extending in the first direction and extending in the second direction intersecting with the first direction. The shape and size of the illuminated area Z are arbitrary, but typically, the illumination device 10 has an illuminated area Z having a longitudinal direction, for example, the ratio of the longitudinal direction to the lateral direction is 10 or more, This is an apparatus for illuminating an illuminated area Z, typically a line-shaped illuminated area Z, in which this ratio is 100 or more. This lighting device can be applied to vehicles such as automobiles and ships. In a vehicle, it is necessary to illuminate an area that extends forward in the direction of travel. In particular, it is preferable that a headlight of an automatic person traveling at a high speed, a so-called headlamp, brightly illuminates the road surface from the vicinity of the front of the automobile to the distance of the front. Further, a searchlight called a searchlight may be required to illuminate only a long and narrow area extending forward. In the illuminating device 10 described here, the illuminated region Z having the longitudinal direction dl, in particular, the illuminated region Z having the longitudinal direction dl located in front of the illuminating device 10 and away from the illuminating device 10 is A device has been devised so that the edges can be clearly lit and can be illuminated safely. Therefore, in application to a headlamp or a search lamp, it is possible to clearly illuminate only a predetermined range to its edge without illuminating a region where illumination is not appropriate, for example, an oncoming lane. Further, by combining with image analysis by a computer, it becomes possible to detect a foreign object or a suspicious object existing in the illuminated area Z with high accuracy.

As shown in FIG. 1, the illuminating device 10 has a light source device 15 that projects light and a hologram element 40 that diffracts the light from the light source device 15 and directs it toward the illuminated region Z. The light source device 15 includes a light source 20 and a shaping optical system 30 that shapes light emitted from the light source 20.

In the example shown in FIG. 1, the light source device 15 has a plurality of light sources 20. A laser light source that oscillates laser light can be used as the light source 20. 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. The plurality of light sources 20 may be provided independently, or may be a light source module in which the plurality of light sources 20 are arranged side by side on a common substrate. As an example, the plurality of light sources 20 include a first laser light source 20a that oscillates light in a red light emission wavelength region, a second laser light source 20b that oscillates light in a green light emission wavelength region, and light in a blue light emission wavelength region. A third laser light source 20c that oscillates. According to this example, it is possible to generate illumination lights of various colors including white illumination light by superimposing the three laser lights emitted from the plurality of light sources 20. However, the light source device 15 is not limited to this example, and the light source device 15 may include two light sources 20 or four or more light sources 20 having different emission wavelength ranges. In order to increase the emission intensity, a plurality of light sources 20 may be provided for each emission wavelength region.

Next, the shaping optical system 30 will be described. The shaping optical system 30 shapes the laser light emitted from the light source 20. In other words, the shaping optical system 30 shapes the shape of the cross section perpendicular to the optical axis of the laser light and the three-dimensional shape of the laser light beam. In the illustrated example, the shaping optical system 30 shapes the laser light emitted from the light source 20 into a widened parallel light beam. As shown in FIG. 1, the shaping optical system 30 includes a lens 31 and a collimating lens 32 in the order along the optical path of the laser light. The lens 31 shapes the laser light emitted from the light source 20 into a divergent light beam. The collimating lens 32 reshapes the divergent light beam generated by the lens 31 into a parallel light beam.

In the illustrated example, the light source device 15 includes a first shaping optical system 30a, a second shaping optical system 30b, and a third shaping optical system 30c corresponding to the first to third laser light sources 20c, respectively. . The first shaping optical system 30a includes a first lens 31a and a first collimating lens 32a, and the second shaping optical system 30b includes a second lens 31b and a second collimating lens 32b, and a third shaping optical system 30c. Has a third lens 31c and a third collimating lens 32c.

Next, the hologram element 40 will be described. The hologram element 40 is a diffractive optical element that diffracts light from the light source device 15 and directs the light toward the illuminated area Z. Therefore, the illuminated area Z is illuminated by the diffracted light from the hologram element 40.

In the illustrated example, the illumination device 10 has a plurality of hologram elements 40. More specifically, the illumination device 10 includes a first hologram element 40a, a second hologram element 40b, and a third hologram element 40c. Each

hologram element

40a, 40b, 40c is provided corresponding to each of the

laser light sources

20a, 20b, 20c that oscillate laser light. According to this example, even when the

laser light sources

20a, 20b, and 20c oscillate laser beams having different wavelength ranges, the

hologram elements

40a, 40b, and 40c are lasers having different wavelength ranges generated by the corresponding laser beams. It becomes possible to diffract light with high efficiency.

As shown in FIG. 2, in the present embodiment, the diffracted light diffracted by the

hologram elements

40a, 40b, and 40c illuminates the entire illuminated area Z, respectively. As will be described later, the diffracted light from the

hologram elements

40a, 40b, and 40c illuminates only the entire illuminated area Z over the entire area, thereby causing uneven brightness and color in the illuminated area Z. The unevenness can be effectively made inconspicuous. In the present specification, the “entire area Z to be illuminated” refers not only to the case where the illumination ranges of the diffracted light diffracted by the

hologram elements

40a, 40b, and 40c completely match, but also to the respective illumination ranges. It means that the deviation is within ± 20%. This numerical range is derived from the experimental results of a prototype of the lighting device 10 produced by the inventor.

In the example shown in FIGS. 1 and 2, the plurality of hologram elements 40 are arranged in a first arrangement direction da that intersects the longitudinal direction dl of the illuminated area Z and is typically vertical. The first arrangement direction da in which the plurality of hologram elements 40 are arranged is parallel to the normal direction nd to the surface pl as a flat surface on which the illuminated area Z is located. In particular, in the illustrated example, the first arrangement direction da in which the plurality of hologram elements 40 are arranged is typically a vertical direction perpendicular to the horizontal direction. That is, in the illustrated example, the diffracted light from the plurality of hologram elements 40 arranged vertically above the ground and the water surface illuminates the horizontal plane pl such as the ground and the water surface and covers the horizontal plane pl. An illumination area Z is formed. The plurality of hologram elements 40 are arranged so as to be shifted in the vertical direction, for example. The number of hologram elements 40 may be two or more, and the number is not limited. For example, when the plurality of hologram elements 40 includes a first hologram element and a second hologram element, and the illuminated area Z has an illumination range extending in a first direction and a second direction intersecting with each other, the illuminated area The illumination range of the diffracted light from the first hologram element is aligned with the illumination range of the diffracted light from the second hologram element in at least one of the first direction and the second direction.

Further, as shown in FIG. 3, each hologram element 40 is divided into a plurality of element holograms 45. Each element hologram 45 is configured as a hologram recording medium on which an interference fringe pattern is recorded. By adjusting the interference fringe pattern in various ways, the traveling direction of the light diffracted by each element hologram 45, in other words, the traveling direction of the light diffused by each element hologram 45 can be controlled. As shown in FIG. 3, the light from the light source device 15 incident on each element hologram 45 is diffracted by the element hologram 45 to illuminate the entire illuminated area Z. As will be described later, the diffracted light from each element hologram element 45 illuminates only the illuminated area Z over the entire area, thereby making the unevenness of brightness in the illuminated area Z effectively inconspicuous. be able to.

In the example shown in FIG. 3, the first hologram element 40a includes a plurality of first element holograms 45a, the second hologram element 40b includes a plurality of second element holograms 45b, and the third hologram element 40c includes a plurality of first element holograms 45a. A three-element hologram 45c is included. In each hologram element 40, the plurality of element holograms 45 are arranged in a first arrangement direction da parallel to the arrangement direction of the plurality of hologram elements 40. That is, the plurality of element holograms 45 included in each hologram element 40 intersects the longitudinal direction dl of the illuminated area Z, typically in a vertical direction and onto the surface pl formed by the illuminated area Z. They are arranged in a first arrangement direction da that intersects the normal direction nd and is typically vertical. Further, in each hologram element 40, the plurality of element holograms 45 are perpendicular to the longitudinal direction dl of the illuminated area Z and are typically perpendicular to the surface pl formed by the illuminated area Z. They are also arranged in a second arrangement direction db that is parallel to the line direction nd. In the illustrated example, the plurality of 45 are arranged in the vertical direction da and the horizontal direction db.

Here, the illuminated area Z can be considered as the illuminated area of the near field illuminated by the hologram element 40. This illuminated area Z can be expressed not only by the actual illuminated area (illumination range) but also by a diffusion angle range in an angular space after setting a certain coordinate axis, as will be described later.

The element hologram 45 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 hologram 45 is irradiated with reference light and object light made of coherent light having coherence with each other, interference fringes due to interference of these lights are generated on the hologram photosensitive material. Thus, the element hologram 45 is produced. As reference light, laser light which is coherent light is used, and as object light, for example, scattered light from an isotropic scattering plate available at low cost is used.

By irradiating the element hologram 45 with a laser beam so that the optical path of the reference light used when the element hologram 45 is manufactured travels in the reverse direction, the source light becomes the source of the object light used when the element hologram 45 is manufactured. A reproduced image of the scattering plate is generated at the position of the scattering plate. If the scattering plate that is the source of the object light used when producing the element hologram 45 has a uniform surface scattering, the reproduced image of the scattering plate obtained by the element hologram 45 also has a uniform surface illumination. An area where a reproduced image of the scattering plate is generated can be set as an illuminated area Z.

Further, the complex interference fringe pattern formed in each element hologram 45 should be reproduced in accordance with the planned wavelength and incident direction of the reproduction illumination light, instead of using the actual object light and the reference light. It is possible to design using a computer based on the shape and position of the image. The element hologram 45 obtained in this way is also called a computer-generated hologram (CGH). For example, when the illumination device 10 is used to illuminate an illuminated area Z having a certain size on the ground surface or water surface, it is difficult to generate object light, and a computer-generated hologram is converted into an element hologram 45. It is preferable to use as.

Further, a Fourier transform hologram having the same diffusion angle characteristic at each point on each element hologram 45 may be formed by computer synthesis. Furthermore, an optical member such as a lens may be provided on the downstream side of the hologram element 40 so that the diffracted light enters the entire illuminated area Z.

One of the advantages of using the hologram element 40 is that the light energy density of light from the light source device 15, for example, laser light, can be reduced by diffusion. Another advantage is that the element hologram 45 can be used as a directional surface light source, so that it can be used on the light source surface to achieve the same illuminance distribution as compared with a conventional lamp light source (point light source). It is possible to reduce the brightness. As a result, even when a laser light source is used as the light source 20, it is possible to contribute to improving the safety of the laser light. Even if the laser light is directly viewed from within the illuminated area Z, the single point light source is directly viewed. Compared to the case, the risk of adverse effects on human eyes is reduced.

On the other hand, the advantage of configuring the hologram element with a plurality of element holograms 45 can sharpen the edge when illuminating the illuminated area Z, particularly the illuminated area Z within a finite distance, as will be described in detail later. Is a point. If the hologram element is a single Fourier type hologram, a blur corresponding to the size of the hologram area occurs in the illuminated area Z. In the present embodiment, it is possible to design the diffraction characteristics of each element hologram 45 in consideration of the positional relationship with the illuminated region Z, and the sharpness of the edge can be significantly improved. That is, by including a plurality of element holograms 45 having different diffraction characteristics in one hologram element 40, it is possible to illuminate the illuminated area Z while making the edges clear. Note that the production of a single Fresnel type hologram by photographing is limited due to the difficulty of preparing object light, and the production of a single Fresnel type computer-generated hologram requires This means that the calculation is performed over the entire area, and substantial restrictions arise from the viewpoint of the amount of calculation.

Furthermore, when coherent light typified by laser light is used, there is a problem of speckle generation as disclosed in, for example, WO2012 / 034174. Speckle is recognized as a speckled pattern and can give physiological discomfort. Since the hologram element 40 includes a plurality of element holograms 45, speckle patterns generated corresponding to the diffracted light from the element holograms 45 are overlapped and averaged in the illuminated area Z and observed by the observer. It will be. As a result, speckles can be made inconspicuous in each element illuminated region Zp.

A specific form of the element hologram 45 may be a volume hologram recording medium using a photopolymer, a volume hologram recording medium of a type that records using a photosensitive medium containing a silver salt material, or a relief. A type (embossed type) hologram recording medium may be used.

Next, the diffraction characteristics of the hologram element 40 will be described.

First, the relationship between the diffraction characteristics of a hologram and the illumination area illuminated by the diffracted light from the hologram will be described with reference to FIGS. Here, FIG. 7 and FIG. 8 are diagrams showing illumination areas Za and Zb by diffracted light from the first hologram 60a and the second hologram 60b having the same diffraction characteristics. Note that “same” means that the deviation of the diffraction characteristics of the first hologram 60a and the second hologram 60b is within ± 20%. This numerical range is derived from the experimental results of a prototype of the lighting device 10 produced by the inventor. In this example, the first hologram 60a and the second hologram 60b irradiate a horizontal plane such as the ground or a water surface with diffracted light and are held above the horizontal plane. That is, the diffracted light from the first hologram 60a and the second hologram 60b travels downward from the horizontal direction and is irradiated to the ground surface pl intended to form the illuminated region Z. For example, in the examples shown in FIGS. 7 and 8, it is assumed that the road surface is illuminated by the headlight of the automobile, as in the examples of FIGS. Similar to the element hologram 45, the

holograms

60a and 60b are intended to diffract light into an illuminated region that is located forward and extends elongated forward. 7 and 8 show the illumination areas Za and Zb of the diffracted light in the

holograms

60a and 60b from the normal direction to the surface pl irradiated with the diffracted light.

In the example shown in FIGS. 7 and 8, the first hologram 60a and the second hologram 60b are mutually aligned along a vertical direction that intersects the longitudinal direction dl of the originally intended illumination area. It is arranged at a position deviated from. In particular, in the example shown in FIG. 7, the arrangement direction of the first hologram 60a and the second hologram 60b is a direction intersecting the normal direction nd to the surface pl on which the illuminated region is formed, typically a horizontal direction. It matches. On the other hand, in the example shown in FIG. 8, the arrangement direction of the first hologram 60a and the second hologram 60b is parallel to the normal direction nd to the surface pl on which the illuminated region is formed, typically vertical. Match the direction. Further, the light beams emitted from the light source device 15 shown in FIG. 1 are incident on the

holograms

60a and 60b. Therefore, in the example shown in FIG. 8, the first hologram 60a and the second hologram 60b are arranged so as to overlap in the depth direction of the paper surface, and the first and second light source devices 15 are arranged in the depth direction of the paper surface. They are placed one on top of the other.

In the example shown in FIG. 7, the illumination area Za by the diffracted light in the first hologram 60a and the illumination area Zb by the diffracted light in the second hologram 60b are shifted in a direction parallel to the arrangement direction of the

holograms

60a and 60b. . Specifically, the illumination area Za illuminated by the diffracted light from the first hologram 60a and the illumination area Zb illuminated by the diffracted light from the second hologram 60b intersect with the longitudinal direction dl of the illumination area. Is shifted in the vertical width direction dw. Therefore, in the illuminated area Zx illuminated by the light emitted from the two

holograms

60a and 60b, both edge portions Zy located on both edges in the width direction dw and extending in the longitudinal direction dl are two

holograms

60a and 60b. Illuminated only by light emitted from one of the two.

In the example shown in FIG. 8, the two

holograms

60a and 60b are arranged so as to be shifted in the normal direction nd to the surface pl irradiated with the diffracted light. That is, the distances from the two

holograms

60a and 60b to the surface pl irradiated with the diffracted light are different. Therefore, as shown in FIG. 8, the illumination area Za illuminated by the diffracted light from the first hologram 60a and the illumination area Zb illuminated by the diffracted light from the second hologram 60b are in the longitudinal direction dl and width of the illumination area. Deviation in both directions dw. Therefore, the peripheral portion Zz of the illuminated area Zx illuminated by the light emitted from the two

holograms

60a and 60b is illuminated only by the light emitted from one of the two

holograms

60a and 60b.

When both edge portions Zy of FIG. 7 and the peripheral portion Zz of FIG. 8 are illuminated only by the diffracted light from one hologram 60, the wavelength regions of the light emitted from the two

holograms

60a and 60b are the same. , It will be lit darker than the other parts. Further, when the wavelength ranges of the light emitted from the two

holograms

60a and 60b are different, both edge portions Zy in FIG. 7 and the peripheral portion Zz in FIG. 8 are illuminated darkly in different colors compared to the other portions. become. That is, when the diffraction characteristics of the two

holograms

60a and 60b are the same, the edge of the illuminated area Z is blurred due to a decrease in brightness or a color change.

In the illumination device 10 shown in FIG. 1 to FIG. 3, the light traveling from the light source device 15 to each hologram element 40 is a parallel light beam as in the examples shown in FIGS. The plurality of hologram elements 40 and the plurality of element holograms 45 are arranged so that the incident surfaces and the emission surfaces thereof are parallel to each other, and incident light on each hologram element 40 and each element hologram 45 is transmitted from the hologram element 40. The light beams are parallel light beams along the normal direction and the normal direction of the element hologram 45.

As shown in FIG. 3, the plurality of element holograms 45 included in each hologram element 40 first intersect with the longitudinal direction dl of the illuminated area Z, typically perpendicular, and the illuminated area Z forms. They are arranged in a second arrangement direction db that intersects the normal direction nd to the surface pl and is typically perpendicular and parallel. The relative positional relationship between the element holograms 45 arranged in the second arrangement direction db is the same as the relative positional relationship between the

holograms

60a and 60b shown in FIG. A plurality of element holograms 45 included in one hologram element 40 are then crossed in the longitudinal direction dl of the illuminated area Z, typically perpendicular to the surface pl formed by the illuminated area Z. They are also arranged in a first arrangement direction da that is parallel to the line direction nd. In addition, since the plurality of hologram elements 40 are arranged in the first arrangement direction da, the element holograms 45 included in the different hologram elements 40 are also arranged in the first arrangement direction da. The relative positional relationship between the element holograms 45 arranged in the first arrangement direction da is the same as the relative positional relationship between the

holograms

60a and 60b shown in FIG.

On the other hand, as shown in FIG. 2, the diffracted light from each hologram element 40 illuminates the entire illuminated area Z. Further, in the illustrated example, as shown in FIG. 3, the diffracted light from each element hologram 45 illuminates only the illuminated area Z over the entire area. In order to realize such illumination, the diffraction characteristics of each element hologram 45 are adjusted as described below.

First, it is assumed that the diffracted light from the element hologram 45 arranged shifted in the second arrangement direction db is the same as that described with reference to FIG. Then, the element hologram 45 is displaced in the second arrangement direction db, which is the arrangement direction of the element hologram 45, and is irradiated onto the surface pl formed by the illuminated region Z. Therefore, as shown in FIG. 4, the irradiation width along the width direction dw of the diffracted light from one element hologram 45s incident on an arbitrary position along the longitudinal direction dl of the illuminated area Z is perpendicular to the longitudinal direction dl. iw is the same as the irradiation width iw along the width direction dw of the diffracted light from the other element hologram 45k incident on the arbitrary position along the longitudinal direction dl of the illuminated region Z. The diffraction characteristics of the element holograms 45 arranged in the second arrangement direction db are adjusted. The adjustment of the diffraction characteristics is performed over the entire area along the longitudinal direction of the illuminated area Z. FIG. 4 is a diagram showing the hologram element 40 and the illuminated region Z by observation from the normal direction nd to the irradiated surface pl that is irradiated with illumination light from the illumination device 10 and includes the illuminated region Z. It is. In this specification, the irradiation width iw “same” means that the deviation of the irradiation width iw is within ± 20%. This numerical range is derived from the experimental results of a prototype of the lighting device 10 produced by the inventor.

In the example shown in FIG. 4, the diffraction characteristics of the light traveling toward the position in the illuminated area Z that is separated from each element hologram 45 along the longitudinal direction dl by the distance R are adjusted according to the width of the illuminated area Z. To do. The diffraction characteristics can also be adjusted using the diffusion angle distribution in the angular space. First, the diffraction characteristic of the reference element hologram 45s is adjusted. For example, in the example shown in FIG. 4, the diffusion angle characteristic of the reference element hologram 45 s toward the position separated by the distance R along the longitudinal direction dl is specified as follows by the coordinate system shown in FIG. 4. The
tan (θ ₁₊ ) = x ⁺ / R
tan (θ ₁ ⁻ ) = x ⁻ / R

Next, the diffusion angle characteristics of the other element hologram 45k, the diffusion angle characteristics of the reference element hologram 45s, and the shift amount a along the second arrangement direction db from the reference element hologram 45s to the element hologram 45k, Determine in consideration of Specifically, it is determined as follows.
tan (θ ₂₊ ) = (x ⁺ + a) / R
tan (θ ₂₋ ) = (x ⁻ −a) / R

The diffusion angle characteristic of the reference element hologram 45s is performed over the entire area along the longitudinal direction dl of the illuminated area Z. Similarly, the diffusion angle characteristic of the other element hologram 45k is also performed over the entire area along the longitudinal direction dl of the illuminated area Z.

Next, the diffracted light from the element hologram 45 arranged so as to be shifted in the first arrangement direction da is described with reference to FIG. 8, assuming that the diffraction characteristics of the element hologram 45 are not adjusted and are the same. Thus, it is displaced in both the front direction seen from the element hologram 45 and the direction perpendicular to the front direction, that is, in the illustrated example, the length of the illuminated area Z on the surface pl on which the illuminated area Z is located. Irradiated with displacement in both the direction dl and the width direction dw. Therefore, in the same manner as the adjustment of the diffraction characteristics of the element hologram 45 arranged in the second arrangement direction db, the same as the adjustment of the diffraction characteristics in the angle space described with reference to FIG. 4 as a specific example. The irradiation width iw along the width direction dw perpendicular to the longitudinal direction dl of the diffracted light from one element hologram 45s incident at an arbitrary position along the longitudinal direction dl of the illuminated area Z is Arranged in the first arrangement direction da so as to be the same as the irradiation width iw along the width direction dw of the diffracted light from the other element holograms 45t, 45n incident on the arbitrary position along the longitudinal direction dl. The diffraction characteristic of the element hologram 45 is adjusted.

Further, as shown in FIG. 5, the irradiation length il along the longitudinal direction dl of the diffracted light from one element hologram 45s incident on an arbitrary position along the width direction dw of the illuminated region Z is expressed as follows. The first length is set to be the same as the irradiation length il along the longitudinal direction dl of the diffracted light from the other one of the element holograms 45t and 45n incident on the arbitrary position along the width direction dw of the region Z. The diffraction characteristics of the element holograms 45 arranged in the arrangement direction da are adjusted. FIG. 5 is a diagram showing the hologram element 40 and the illuminated region Z on a plane parallel to both the normal direction nd to the irradiation surface pl formed by the illuminated region Z and the first arrangement direction da. In the present specification, “the same irradiation length il” means that the deviation of the irradiation length il is within ± 20%. This numerical range is derived from the experimental results of a prototype of the lighting device 10 produced by the inventor.

In the example shown in FIG. 5, the diffraction characteristics of light traveling from the element hologram 45 arranged in the first arrangement direction da to an arbitrary position in the width direction dw are adjusted according to the length of the illuminated region Z. The diffraction characteristics can also be adjusted using the diffusion angle distribution in the angular space. First, the diffraction characteristic of the reference element hologram 45s is adjusted. For example, in the example shown in FIG. 5, the diffusion angle characteristic of the reference element hologram 45 s directed to an arbitrary position in the width direction dw is specified as follows by the coordinate system shown in FIG. 5.
tan (θ ₃₊ ) = h / y
tan (θ ₃₋ ) = h / (y + il)
Note that “h” in the equation is the distance along the first arrangement direction da from the irradiation surface pl where the illuminated region Z is formed to the reference element hologram 45, that is, the height of the position where the reference element hologram 45 is arranged. It corresponds to.

Next, the diffusion angle characteristic of the other element hologram 45t included in the same first hologram element 40a as the reference element hologram 45s is changed from the diffusion angle characteristic of the reference element hologram 45s to the element hologram from the reference element hologram 45s. This is determined in consideration of the shift amount b along the first arrangement direction da up to 45t. Specifically, it is determined as follows. Note that in this specification, the diffusion angle characteristics “same” means that the deviation of the diffusion angle characteristics is within ± 20%. This numerical range is derived from the experimental results of a prototype of the lighting device 10 produced by the inventor.
tan (θ ₄₊ ) = (h−b) / y
tan (θ _{4 −} ) = (h−b) / (y + il)

Further, the diffusion characteristics can be similarly determined for other element holograms 45n included in the hologram element 40 different from the reference element hologram 45s. That is, the diffusion angle characteristics of the other element hologram 45n included in the third hologram element 40c are the same as the diffusion angle characteristics of the reference element hologram 45s and the first arrangement direction da from the reference element hologram 45s to the element hologram 45n. It can be determined in consideration of the shift amount c along Specifically, it is determined as follows.
tan (θ ₅₊ ) = (h−c) / y
_{tan (θ 5-) = (h} -c) / (y + il)

The diffusion angle characteristic in the longitudinal direction dl of the reference element hologram 45s is performed over the entire area along the width direction dw of the illuminated area Z. Similarly, the diffusion angle characteristics of the other element holograms 45t and 45n are also performed over the entire area along the width direction dw of the illuminated area Z.

By adjusting the diffraction characteristics of the hologram element 40 and the element hologram 45 as described above, the diffracted light from each hologram element 40 illuminates only the illuminated area Z over the entire area. The diffracted light from the hologram 45 illuminates only the illuminated area Z over the entire area.

According to the present embodiment described above, the diffraction characteristics of each hologram element 40 are adjusted according to the difference in the arrangement position of the plurality of hologram elements 40. As a result, the diffracted light from each hologram element 40 is Each of the illuminated areas Z is illuminated. Therefore, if the diffracted light from the plurality of hologram elements 40 is light in the same wavelength range, the illuminated area Z can be illuminated brightly. Further, if the diffracted light from the plurality of hologram elements 40 is light in different wavelength ranges, the illuminated area Z can be illuminated with a desired color by additive color mixing. In the present embodiment, the diffracted light from each hologram element 40 illuminates the illuminated area Z, so that the light emission points are dispersed, which has an adverse effect on the human eye directly viewing the illumination device 10. The degree can be reduced. In addition, since the diffracted light from each hologram element 40 illuminates the entire illuminated area Z, it is possible to effectively suppress uneven brightness and color unevenness in the vicinity of the edge of the illuminated area Z. it can. As a result, the illuminated area Z can be safely illuminated while its edges are clear.

Further, in the present embodiment, the illuminated area Z having the longitudinal direction dl is illuminated by the diffracted light from the hologram element 40. Therefore, by adjusting the diffraction characteristics of the hologram element 40, the illumination device 10 can be used even when the illuminated area Z is located in front of the illumination device 10 and has a longitudinal direction dl in a direction away from the illumination device 10. It is possible to brightly illuminate a distant area away from the object with higher light irradiation intensity. As a result, the illuminated area Z having the longitudinal direction dl, for example, the illuminated area Z in which the ratio of the length in the longitudinal direction dl to the length in the width direction dw is 10 or more, and further this ratio is 100 or more, more typically In this case, it is possible to safely illuminate the line-shaped illuminated area Z while making the edge clear.

The plurality of hologram elements 40 are arranged in a first arrangement direction da that is perpendicular to the longitudinal direction dl of the illuminated area Z and is parallel to the normal direction nd to the surface pl on which the illuminated area Z is formed. As a method for adjusting the diffraction characteristics of the hologram elements 40 when arranged, diffraction from one hologram element 40 incident at an arbitrary position along the width direction dw orthogonal to the longitudinal direction dl of the illuminated area Z The irradiation length il along the longitudinal direction dl of the light is along the longitudinal direction dl of the diffracted light from the other hologram element 40 incident on the arbitrary position along the width direction dw of the illuminated area Z. Further, the irradiation width iw along the width direction dw of the diffracted light from one hologram element 40 incident on an arbitrary position along the longitudinal direction dl of the illuminated area Z is made equal to the irradiation length il. But And irradiation width iw along the width direction dw of the diffracted light from one hologram element 40 other incident on the arbitrary position along the longitudinal direction dl in the illuminated area Z, may be the same. Such adjustment can be realized while the lighting device 10 is simply reduced in size. Accordingly, it is possible to safely illuminate the illuminated area Z having the longitudinal direction dl, typically the line-shaped illuminated area Z, while making the edges clear, while allowing the lighting device 10 to be simply reduced in size. it can.

Further, according to the present embodiment, the hologram element 40 includes a plurality of element holograms 45. Then, the diffraction characteristics of each element hologram 45 are adjusted according to the difference in arrangement position of the plurality of element holograms 45. As a result, the diffracted light from each element hologram 45 illuminates the entire illuminated area Z, respectively. To do. Therefore, uneven brightness in the vicinity of the edge of the illuminated area Z can be effectively suppressed. Thereby, it is possible to illuminate the illuminated area Z while making the edges clear. Further, one hologram element 40 has the same number of light emitting points as the number of element holograms 45, and the degree of adverse effects on the human eye that directly views the illumination device 10 can be reduced. In addition, since the diffracted light from each element hologram 45 is superimposed on the illuminated area Z, speckle can be effectively made inconspicuous even when laser light is used.

Further, the illuminated area Z having the longitudinal direction dl is illuminated by the diffracted light from each element hologram 45. Therefore, by adjusting the diffraction characteristics of the element hologram 45, the illumination device 10 can be used even when the illuminated region Z is located in front of the illumination device 10 and has a longitudinal direction dl in a direction away from the illumination device 10. It is possible to brightly illuminate a distant area away from the object with higher light irradiation intensity. As a result, it is possible to safely illuminate the illuminated area Z having the longitudinal direction dl, typically a line-shaped illuminated area Z, with sharp edges.

The plurality of element holograms 45 are arranged in a second arrangement direction db perpendicular to the longitudinal direction dl of the illuminated area Z and perpendicular to the normal direction nd to the surface pl on which the illuminated area Z is formed. As a method of adjusting the diffraction characteristics of each element hologram 45 in the case where it is applied, it is orthogonal to the longitudinal direction dl of the diffracted light from one element hologram 45 incident at an arbitrary position along the longitudinal direction dl of the illuminated area Z. The irradiation width iw along the width direction dw is the irradiation width iw along the width direction dw of the diffracted light from the other one-element hologram 45 incident on the arbitrary position along the longitudinal direction dl of the illuminated region Z. And may be the same. Such adjustment can be realized while the lighting device 10 is simply reduced in size. Accordingly, it is possible to safely illuminate the illuminated area Z having the longitudinal direction dl, typically the line-shaped illuminated area Z, while making the edges clear, while allowing the lighting device 10 to be simply reduced in size. it can.

In addition, the plurality of element holograms 45 are in a first arrangement direction da that is perpendicular to the longitudinal direction dl of the illuminated area Z and is parallel to the normal direction nd to the surface pl on which the illuminated area Z is formed. As a method of adjusting the diffraction characteristics of the element holograms 45 when arranged, diffraction from one element hologram 45 incident on an arbitrary position along the width direction dw orthogonal to the longitudinal direction dl of the illuminated area Z The irradiation length il along the longitudinal direction dl of the light is along the longitudinal direction dl of the diffracted light from the other element hologram 45 incident on the arbitrary position along the width direction dw of the illuminated region Z. Further, the irradiation width iw along the width direction dw of the diffracted light from one element hologram 45 incident on an arbitrary position along the longitudinal direction dl of the illuminated area Z is made equal to the irradiation length il. But And irradiation width iw along the width direction dw of the diffracted light from the other one element hologram 45 to be incident on the arbitrary position along the longitudinal direction dl in the illuminated area Z, it may be the same. Such adjustment can be realized while the lighting device 10 is simply reduced in size. Accordingly, it is possible to safely illuminate the illuminated area Z having the longitudinal direction dl, typically the line-shaped illuminated area Z, while making the edges clear, while allowing the lighting device 10 to be simply reduced in size. it can.

Furthermore, in the above-described embodiment, the light source device 15 includes the light source 20 that generates the laser light and the shaping optical system 30 that shapes the light emitted from the light source 20. In particular, in the illustrated example, the shaping optical system 30 converts the light from the light source 20 into a parallel light beam. Accordingly, a parallel light beam enters each element hologram 45 of the hologram element 40. According to this example, the design and manufacture of the hologram element 40 and the element hologram 45 can be facilitated. Further, the diffraction by the hologram element 40 enables the light to be directed to the entire area within the illuminated area Z with high accuracy.

Note that various modifications can be made to the above-described embodiment. Hereinafter, an example of modification will be described with reference to the drawings. In the following description and the drawings used in the following description, the same reference numerals as those used for the corresponding parts in the above-described embodiment are used for parts that can be configured in the same manner as in the above-described embodiment, and overlapping Description to be omitted is omitted.

In the above-described embodiment, as shown in FIG. 1, the plurality of hologram elements 40 are normal to the surface pl that is perpendicular to the longitudinal direction dl of the illuminated area Z and on which the illuminated area Z is formed. An example in which the elements are arranged in the first arrangement direction da that is parallel to the direction nd is shown. That is, the example in which the plurality of hologram elements 40 are arranged in the vertical direction when the illuminated region Z is provided on a horizontal surface such as the ground surface or the water surface is shown. However, the present invention is not limited to this example, and a plurality of hologram elements 40 may be arranged as shown in FIG. In the example shown in FIG. 6, the plurality of hologram elements 40 are perpendicular to the longitudinal direction dl of the illuminated area Z and perpendicular to the normal direction nd to the surface pl on which the illuminated area Z is formed. They are arranged in the direction, that is, in the second arrangement direction db described above. More specifically, when the illuminated area Z is provided on a horizontal plane such as the ground or the water surface, the plurality of hologram elements 40 may be arranged in the horizontal direction. Also in this example, the diffraction characteristic of each hologram element 40 is adjusted according to the difference in the arrangement position of the plurality of hologram elements 40, and as a result, the diffracted light from each hologram element is transmitted over the entire illuminated area Z. Can be illuminated. By adjusting the diffraction characteristics of the hologram element 40 in this way, the same effects as those of the above-described embodiment can be obtained.

The plurality of hologram elements 40 are arranged in a second arrangement direction db perpendicular to the longitudinal direction dl of the illuminated area Z and perpendicular to the normal direction nd to the surface pl on which the illuminated area Z is formed. As described above with reference to FIG. 4, as a method for adjusting the diffraction characteristics of each hologram element 40 in the case where it is applied, one hologram element 40 that is incident on an arbitrary position along the longitudinal direction dl of the illuminated area Z. Diffraction from one other hologram element 40 in which the irradiation width iw along the width direction dw perpendicular to the longitudinal direction dl of the diffracted light from the incident light enters the arbitrary position along the longitudinal direction dl of the illuminated area Z The irradiation width iw along the light width direction dw may be the same. Such adjustment can be realized while the lighting device 10 is simply reduced in size. Accordingly, it is possible to safely illuminate the illuminated area Z having the longitudinal direction dl, typically the line-shaped illuminated area Z, while making the edges clear, while allowing the lighting device 10 to be simply reduced in size. it can.

In the embodiment described above, the example in which the hologram element 40 is divided into a plurality of element holograms 45 has been described. However, the present invention is not limited to this example, and each hologram element 40 may be formed as a single hologram. Also in such a modification, the diffracted light from each of the plurality of hologram elements 40 included in the illumination device 10 is incident on the entire illuminated area Z, thereby having a longitudinal direction. It is possible to safely illuminate an illumination area, typically a line-like illuminated area, with sharp edges.

Furthermore, in the above-described embodiment, an example in which the illumination device 10 includes a plurality of hologram elements 40 has been described. However, the present invention is not limited to this example, and the illumination device 10 may include only a single hologram element 40. Good. In this example, the hologram element 40 includes a plurality of element holograms 45, and the diffracted light from each element hologram 45 has a longitudinal direction by being incident on the entire illuminated area Z. The illuminated area, typically a line-shaped illuminated area, can be safely illuminated with sharp edges.

Furthermore, in the above-described embodiment, an example in which a separate light source device 15 is prepared for each of the plurality of hologram elements 40 has been described. However, the present invention is not limited to this. Any one of the light source 20, the shaping optical system 30, and the lens 31 may be shared among the plurality of hologram elements 40.

Further, as shown in FIG. 9, each of the first to third laser light sources 20a to 20c of the light source device 15 includes a first light emitting unit 151 having a major axis direction d1 and a minor axis direction d2 orthogonal thereto, You may have the 2 light emission part 152 and the 3rd light emission part 153. FIG. In FIG. 9, for convenience, the first to third laser light sources 20a to 20c, the first to third shaping optical systems 30a to 30c, and the first to third hologram elements 40a to 40c are collectively illustrated. Show. The actual laser light sources 20a to 20c, shaping optical systems 30a to 30c and hologram elements 40a to 40c may be arranged in the vertical direction as shown in FIG. 1, or as shown in FIG. It may be arranged in the direction.

Here, the major axis direction d1 of the light emitting units 151 to 153 is a direction in which the diffusion angle is maximized in the diffusion direction of the laser light emitted from the light emitting units 151 to 153. It can also be said that the major axis direction d1 is a direction parallel to the maximum diameter of the cross section of the laser beam orthogonal to the optical axis. In the illustrated example, the major axis direction d1 coincides with the vertical direction. Further, the minor axis direction d2 is a direction in which the diffusion angle is minimum among the diffusion directions of the laser light emitted from the light emitting units 151 to 153. It can also be said that the minor axis direction d2 is a direction parallel to the minimum diameter of the cross section of the laser beam orthogonal to the optical axis. In the illustrated example, the minor axis direction d2 coincides with the horizontal direction.

The light emitting units 151 to 153 are arranged at the same position in the short axis direction d2 with an interval in the long axis direction d1. That is, the laser light sources 20a to 20c are arranged in the casing 150 of the light source device 15 in such a posture that the short axis direction d2 of the light emitting units 151 to 153 is parallel to the width direction dw of the illuminated area Z, that is, the horizontal direction. ing.

The laser light L emitted from the light emitting portions 151 to 153 of the laser light sources 20a to 20c arranged in this way so as to spread in the short axis direction d2 is shaped by the shaping optical systems 30a to 30c, and then the hologram elements 40a to 40c. It is shaped to expand in the width direction dw at 40c.

If the long axis direction d1 is parallel to the width direction dw, the light emitting units 151 to 153 emit laser light diffused with a large diffusion angle in the width direction dw. Laser light having a large diffusion angle is difficult to be collimated sufficiently by the collimating lenses 32a to 32c of the shaping optical systems 30a to 30c. When trying to shape laser light that is insufficiently collimated into diffracted light having an intended beam shape by the hologram elements 40a to 40c, a burden is imposed on the shape of the hologram elements 40a to 40c, and the cost of the hologram elements 40a to 40c is increased. However, there is a risk of increasing the dimensional accuracy.

On the other hand, according to the example shown in FIG. 9, the laser beam L can be emitted from the light emitting units 151 to 153 with a small diffusion angle in the width direction dw. Since the laser light L having a small diffusion angle can be sufficiently collimated by the collimating lenses 32a to 32c of the shaping optical systems 30a to 30c, the desired beam shape can be obtained without imposing a burden on the shape of the hologram elements 40a to 40c. Can be obtained.

Therefore, according to the example shown in FIG. 9, it is possible to illuminate the line-shaped light with clear edges on the road surface reliably and at low cost.

In FIG. 4 described above, the illumination light beam Z extends the illumination light beam in which the center line L1 extending in the longitudinal direction through the center position in the width direction orthogonal to the longitudinal direction of the illumination area extends in the longitudinal direction through the center position of the hologram element 40. Although the example which corresponds with the projection line L2 projected on a certain surface was shown, as shown in FIG. 10, the above-mentioned center line L1 of the illuminated area Z may be displaced from the projection line L2.

In FIG. 10, as in FIG. 4, the width in the short direction of the illuminated area Z is iw, the horizontal width of the hologram element 40 is a, and the shortest distance from the hologram element 40 to the nearest position of the illuminated area Z R, the distance between the first edge e1 in the longitudinal direction of the illuminated area Z and the first end line e2 that passes through the first horizontal end of the hologram element 40 and extends in the longitudinal direction of the illuminated area Z is x +, The distance between the second edge e3 in the longitudinal direction of the illuminated area Z and the second end line e4 extending in the longitudinal direction of the illuminated area Z through the second horizontal end of the hologram element 40 is represented by x- It is said. Further, when the boundary position in the minor axis direction is p1 and p2 through an arbitrary position of the illuminated area Z, the angle formed by the position p1 and the first end line e2 is θ1 +, and the position p2 and the first end line. When the angle formed by e2 is θ1-, the angle formed by the position p1 and the second end line e4 is θ2 +, and the angle formed by the position p2 and the second end line e4 is θ2-, the following expression is established.

tan (θ ₁₊ ) = x ⁺ / R
_{^{tan (θ 1-) = (x}} + -iw) / R
tan (θ ₂₊ ) = (x ⁺ + a) / R
tan (θ ₂₋ ) = x ⁻ / R

Thus, by designing the diffraction characteristics of the hologram element 40 so as to satisfy the above formula, the illuminated area Z in an arbitrary direction and position with respect to the hologram element 40 can be illuminated.

A part of the laser light incident on the hologram element 40 is not diffracted by the hologram element 40 and becomes zero-order light that is transmitted as it is. When the 0th-order light is irradiated onto the illuminated area Z, only the 0th-order light irradiation position in the illuminated area Z designed in advance has high illuminance specifically. Using the position of the hologram element 40 as a reference, comparing the case where the zero-order light is irradiated on the nearest end side in the longitudinal direction of the illuminated area Z and the case where it is irradiated on the farthest end side, the nearest end side is irradiated. In this case, the irradiation area of the 0th-order light becomes smaller, the illuminance per unit area becomes higher, and the irradiation position of the 0th-order light in the illuminated area Z becomes more conspicuous. Therefore, it is desirable to design the diffraction characteristics of the hologram element 40 so that the zero-order light is incident on the farthest end side with respect to the nearest end in the longitudinal direction of the illuminated region Z. Thereby, the dispersion | variation in the light intensity, ie, illumination intensity, in the whole illuminated area Z can be suppressed.

In FIG. 1 and the like, the laser light is collimated by the collimating lenses 32a to 32c of the shaping optical systems 30a to 30c and then incident on the hologram elements 40a to 40c. In order to suppress the blur of the illuminated area Z, it is desirable to collimate the incident light on the hologram elements 40a to 40c. However, the collimated laser light has a small incident area on the hologram elements 40a to 40c. Accordingly, the light intensity of the 0th order light is increased. Therefore, from the viewpoint of reducing the light intensity of the zeroth-order light, the diffused light in which the incident light to the hologram elements 40a to 40c is slightly spread is more desirable than the perfect parallel light. If diffused light is incident on the hologram elements 40a to 40c, the amount of blur in the illuminated area Z may increase. However, as described with reference to FIG. 3 and the like, the hologram elements 40a to 40c are formed on the plurality of element holograms 45. In the case where the element holograms 45 are divided and have diffraction characteristics that illuminate the entire illuminated area Z, even if the incident light to the hologram elements 40a to 40c is diffused light, Since the incident angles of the laser beams incident on the element hologram 45 are considered to be almost the same, if the diffraction characteristics are designed so as to illuminate the entire illuminated area Z for each element hologram 45, the hologram elements 40a to 40c. As a whole, the illuminated area Z can be illuminated clearly.

In FIG. 1 and the like, an example in which transmissive hologram elements 40a to 40c are used as diffractive optical elements has been shown, but reflective hologram elements 40a to 40c may be used as shown in FIG. With the reflection type hologram elements 40a to 40c, since the traveling direction of the 0th-order light is different from the observation direction of the observer, a safety measure against the 0th-order light can be facilitated.

In addition, although the some modification with respect to embodiment mentioned above was demonstrated above, naturally, it is also possible to apply combining several modifications suitably.

Claims

An illumination device that illuminates an illuminated area that extends in a first direction and extends in a second direction that intersects the first direction,
A light source;
A diffractive optical element having a first hologram element and a second hologram element for diffracting light from the light source and directing the light toward the illuminated region,
The illuminating device, wherein the diffracted light from the first hologram element illuminates the entire area of the illuminated area, and the diffracted light from the second hologram element illuminates the entire area of the illuminated area.
The irradiation width along the second direction intersecting the first direction of the diffracted light from the first hologram element that enters the arbitrary position along the first direction of the illuminated area is the width of the illuminated area. 2. The illumination device according to claim 1, wherein the illumination width is the same as an irradiation width along the second direction of the diffracted light from the second hologram element incident on the arbitrary position along the first direction.
The irradiation length along the first direction of the diffracted light from the first hologram element incident on an arbitrary position along the second direction intersecting the first direction of the illuminated area is the illumination area. The irradiation length along the first direction of the diffracted light from the second hologram element incident on the arbitrary position along the second direction is the same as the irradiation length along the first direction. Lighting device.
An illumination device that illuminates an illuminated area that extends in a first direction and extends in a second direction that intersects the first direction,
A light source;
A diffractive optical element having a first hologram element and a second hologram element for diffracting light from the light source and directing the light toward the illuminated region,
In at least one of the first direction and the second direction of the illuminated area, the illumination range of the diffracted light from the first hologram element is aligned with the illumination range of the diffracted light from the second hologram element. , Lighting equipment.
The first hologram element and the second hologram element are arranged in a direction intersecting a first direction of the illuminated area and a direction intersecting a normal direction to a surface on which the illuminated area is formed. Has been
The irradiation width along the second direction intersecting the first direction of the diffracted light from the first hologram element that enters the arbitrary position along the first direction of the illuminated area is the width of the illuminated area. The irradiation width along the second direction of the diffracted light from the second hologram element incident on the arbitrary position along the first direction is the same as any one of claims 1 to 4. The lighting device according to item.
The first hologram element and the second hologram element are arranged in a direction intersecting a first direction of the illuminated area and along a normal direction to a surface on which the illuminated area is formed. Has been
The irradiation length along the first direction of the diffracted light from the first hologram element incident on an arbitrary position along the second direction intersecting the first direction of the illuminated area is the illumination area. The irradiation length along the first direction of the diffracted light from the second hologram element that enters the arbitrary position along the second direction is the same as
The irradiation width along the second direction of the diffracted light from the first hologram element incident on an arbitrary position along the first direction of the illuminated area is along the first direction of the illuminated area. The illumination device according to any one of claims 1 to 5, wherein the illumination width along the second direction of the diffracted light from the second hologram element incident on the arbitrary position is the same. .
The first hologram element includes a plurality of element holograms,
The illuminating device according to any one of claims 1 to 6, wherein diffracted light from at least two element holograms among the plurality of element holograms illuminates the entire area to be illuminated.
The second hologram element includes a plurality of element holograms,
The illuminating device according to any one of claims 1 to 7, wherein diffracted light from at least two or more element holograms of the plurality of element holograms illuminates the entire area to be illuminated.
The irradiation width along the second direction intersecting the first direction of diffracted light from one element hologram incident on an arbitrary position along the first direction of the illuminated region is the irradiation width of the illuminated region. The illumination according to claim 7 or 8, wherein the illumination width is the same as the irradiation width along the second direction of the diffracted light from another element hologram incident on the arbitrary position along the first direction. apparatus.
The irradiation length along the first direction of the diffracted light from one element hologram incident on an arbitrary position along the second direction intersecting the first direction of the illuminated area is the length of the illuminated area. 10. The irradiation length along the first direction of the diffracted light from the other one element hologram element incident on the arbitrary position along the second direction is the same as the irradiation length along the first direction. The lighting device according to claim 1.
The plurality of element holograms are arranged in a direction intersecting a first direction of the illuminated area and a direction intersecting a normal direction to a surface on which the illuminated area is formed,
The irradiation width along the second direction intersecting the first direction of diffracted light from one element hologram incident on an arbitrary position along the first direction of the illuminated region is the irradiation width of the illuminated region. 11. The irradiation width along the second direction of the diffracted light from another element hologram incident on the arbitrary position along the first direction is the same as the irradiation width along the second direction. The lighting device according to item.
The plurality of element holograms are arranged in a direction intersecting a first direction of the illuminated area and along a normal direction to a surface on which the illuminated area is formed,
The irradiation length along the first direction of the diffracted light from one element hologram incident on an arbitrary position along the second direction intersecting the first direction of the illuminated area is the length of the illuminated area. The irradiation length along the first direction of the diffracted light from the other one element hologram incident on the arbitrary position along the second direction is the same,
The irradiation width along the second direction of the diffracted light from the one element hologram incident on an arbitrary position along the first direction of the illuminated area is along the first direction of the illuminated area. The illumination according to any one of claims 7 to 11, wherein the illumination width is the same as the irradiation width along the second direction of the diffracted light from another element hologram incident on the arbitrary position. apparatus.
The light source includes a first coherent light source and a second coherent light source,
A first shaping optical system that shapes light from the first coherent light source and directs the light toward the first hologram element, and a second shaping optical system that shapes light from the second coherent light source and directs the light to the second hologram element The lighting device according to any one of claims 1 to 12, further comprising:
An illumination device for illuminating an illuminated area having a first direction,
A light source;
A diffractive optical element having a hologram element that diffracts light from the light source and directs it to the illuminated area, and
The hologram element includes a plurality of element holograms,
The illuminating device, wherein diffracted light from at least two element holograms among the plurality of element holograms illuminates the entire area to be illuminated.
The light source includes a light emitting unit having a major axis direction and a minor axis direction intersecting the major axis direction,
The shaping optical system according to any one of claims 1 to 14, further comprising a shaping optical system that shapes light spreading in the minor axis direction from the light emitting unit so as to spread in a second direction intersecting the first direction by the hologram element. The lighting device described in 1.
An illumination device for illuminating an illuminated area having a first direction,
A light source having a major axis direction and a minor axis direction intersecting the major axis direction and including a light emitting unit that emits coherent light;
A diffractive optical element having a hologram element that diffracts coherent light from the light source and directs it to the illuminated area, and
The illuminating device shaped so that the coherent light spreading in the minor axis direction from the light emitting unit spreads in the second direction intersecting the first direction by the hologram element.
A shaping optical system that shapes the coherent light from the light source and directs it to the hologram element,
The illumination device according to claim 16, wherein coherent light spreading in the minor axis direction from the light emitting unit is shaped so as to spread in the second direction by the hologram element after being shaped by the shaping optical system.
The illumination device according to claim 16 or 17, wherein the shaping optical system includes a collimator lens that shapes coherent light from the light source into parallel light.
The lighting device according to any one of claims 16 to 18, wherein the minor axis direction is parallel to the second direction.
The diffractive optical element has a center line extending in the first direction through a center position in a second direction intersecting the first direction of the illuminated area, and the first line passing through a center position of the diffractive optical element. The illuminating device according to any one of claims 1 to 19, wherein the illuminating region is illuminated such that a projection line obtained by projecting an illumination light beam extending in a direction onto the illuminating region deviates.
The light emitted from the light source is coherent light,
The diffractive optical element is configured such that, of the coherent light incident on the diffractive optical element, zero-order light that has not been diffracted by the diffractive optical element and passes through the diffractive optical element is the first direction of the illuminated region. The illuminating device according to any one of claims 1 to 20, wherein the illuminated area is illuminated so that the light is incident on the farthest end side than the nearest end.
The illuminating device according to any one of claims 1 to 21, wherein light emitted from the light source and incident on the diffractive optical element is diffused light that spreads more than parallel light.