JP2021007099A - Lighting device, method for manufacturing lighting device and lighting method - Google Patents

Abstract

To miniaturize a lighting device while taking account of safety.SOLUTION: A lighting device 10 includes: multiple laser light sources 20 with different radiation fluxes; and a diffractive optical element 40 installed while corresponding to each of the multiple laser light sources. The diffractive optical element 40 corresponding to the laser light source 20 with the smallest radiation flux has an area that is smaller than an area of the diffractive optical element 40 corresponding to the laser light source 20 with the largest radiation flux.SELECTED DRAWING: Figure 1

Description

Embodiments of the present disclosure relate to lighting equipment.

For example, as disclosed in Patent Document 1, a lighting device including a light source and a hologram element is known. In the lighting device disclosed in Patent Document 1, the hologram element can diffract the light from the light source to illuminate the road surface in a desired pattern. In the lighting device disclosed in Patent Document 1, a laser beam generated by a single light source is diffracted by a single hologram element.

Japanese Unexamined Patent Publication No. 2015-132707

By the way, when a light source that irradiates a laser beam is used, the illuminated area can be brightly illuminated. However, when the illumination light from the lighting device is directly viewed, there is a risk of adversely affecting the human eye. Then, in consideration of safety, it is preferable to increase the area of the hologram element to secure a large incident region (spot region) of the light source light on the hologram element. However, if the area of the hologram element is increased, there is a problem that the lighting device as a whole becomes large. The problem of increasing the size of the lighting device becomes more serious in the lighting device that illuminates with a specific color by additive color mixing using light in a plurality of wavelength ranges.

The embodiment of the present disclosure has been made in consideration of the above points, and an object of the present disclosure is to reduce the size of the lighting device while considering safety.

The lighting device according to the embodiment of the present disclosure is
Multiple laser light sources that emit laser light from different radiant fluxes,
A diffractive optical element provided corresponding to each of the plurality of laser light sources is provided.
The area of the diffractive optical element corresponding to the laser light source that emits the laser light that is the smallest radiation bundle is smaller than the area of the diffractive optical element that corresponds to the laser light source that emits the laser light that is the largest radiation bundle. There is.

In the illumination device according to the embodiment of the present disclosure, the light emitted from each of the plurality of laser light sources is diffracted by the diffractive optical element corresponding to each laser light source, and then illuminates at least a partially overlapping region. It may be.

In the illumination device according to the embodiment of the present disclosure, the light emitted from each of the plurality of laser light sources is diffracted by the diffractive optical element corresponding to each laser light source, and then illuminates the same illuminated area. You may.

In the illumination device according to the embodiment of the present disclosure, the light emitted from each of the plurality of laser light sources is diffracted by the diffractive optical element corresponding to each laser light source, and then illuminates only the entire area of the same illuminated area. You may try to do it.

In the lighting device according to the embodiment of the present disclosure, when the minimum radiant flux is W _min [W] and the maximum radiant flux is W _max [W], the laser beam which becomes the minimum radiant flux is emitted. The area of the diffractive optical element corresponding to the laser light source A _min [mm ² ] and the area A _max [mm ² ] of the diffractive optical element corresponding to the laser light source that emits the laser light that becomes the maximum radiant flux are The following relationships may be satisfied.
A _max × (W _min / W _max ) ≦ A _min

In the illumination device according to the embodiment of the present disclosure, the area of the diffractive optical element corresponding to one arbitrarily selected laser light source is a laser beam having a radiation bundle larger than the laser beam emitted by the one laser light source. It may be less than or equal to the area of the diffractive optical element corresponding to one other laser light source that emits.

The lighting device according to the embodiment of the present disclosure may further include a shaping optical system that magnifies the laser light emitted from the plurality of laser light sources and guides the laser light to the diffractive optical element.

According to the embodiment of the present disclosure, the lighting device can be miniaturized while considering safety.

FIG. 1 is a diagram for explaining one embodiment according to the present disclosure, and is a perspective view showing a lighting device. FIG. 2 is a front view showing the lighting device of FIG. FIG. 3 is a side view showing the lighting device of FIG.

Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. In the drawings attached to the present specification, the scale, aspect ratio, etc. are appropriately changed from those of the actual product and exaggerated for the convenience of illustration and comprehension.

In addition, the terms such as "parallel", "orthogonal", and "same", and the values of length and angle, etc., which specify the shape and geometric conditions and their degrees as used in the present specification, are strictly referred to. It is interpreted to include the range in which similar functions can be expected, without being bound by any meaning.

FIG. 1 is a perspective view schematically showing the overall configuration of the lighting device 10. The lighting device 10 is a device that illuminates the illuminated area Z. In the illustrated example, the illuminated area Z is an elongated area having a longitudinal direction dl. The illuminated area Z is, for example, an illuminated area Z in which the ratio of the length in the longitudinal direction dl to the length in the lateral direction dw is 10 or more, and further, this ratio is 100 or more, typically a line shape. Can be the illuminated area Z of. Such a lighting device can be applied to vehicles such as automobiles and ships, for example. Vehicles need to illuminate areas that extend forward in the direction of travel. In particular, it is preferable that the headlights of an automatic person traveling at high speed, so-called headlamps, brightly illuminate the road surface from the vicinity of the front to the far front of the vehicle.

As shown in FIG. 1, the lighting device 10 includes a light source device 15 that projects light, and a diffracting optical 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 laser light source 20 and a shaping optical system 30 that shapes the light emitted from the laser light source 20.

As shown in FIG. 1, the light source device 15 has a plurality of laser light sources 20. The laser light projected from the laser light source has excellent straightness and is suitable as light for illuminating the illuminated area Z with high accuracy. The plurality of laser light sources 20 may be provided independently, or may be a light source module in which a plurality of laser light sources 20 are arranged side by side on a common substrate. As an example, the plurality of laser light sources 20 include a first laser light source 20a that oscillates light in a red emission wavelength region, a second laser light source 20b that oscillates light in a green emission wavelength region, and a blue emission wavelength region. It has a third laser light source 20c that oscillates light. According to this example, by superimposing three laser beams emitted by a plurality of laser light sources 20, it is possible to illuminate the illuminated area Z with illumination light of a desired color. By adjusting the radiant flux [unit: W] of the laser light emitted from the plurality of laser light sources 20, the color of the illumination light can be adjusted.

However, the present invention is not limited to the above examples, and the light source device 15 may have two laser light sources 20 or four or more laser light sources 20 having different emission wavelength ranges. Further, in order to increase the emission intensity, a plurality of laser light sources 20 may be provided for each emission wavelength range.

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

In the illustrated example, the light source device 15 has 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 20a to 20c, respectively. ing. The first shaping optical system 30a has a first lens 31a and a first collimating lens 32a, the second shaping optical system 30b has 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 diffractive optical element 40 will be described. The diffractive optical element 40 is an element that exerts a diffracting action on the light emitted from the light source device 15. The illustrated diffractive optical element 40 diffracts the light from the light source device 15 and directs it to the illuminated region Z. Therefore, the illuminated area Z is illuminated by the diffracted light of the diffractive optical element 40.

In the illustrated example, the illuminating device 10 has a plurality of diffractive optical elements 40. More specifically, the lighting device 10 includes a first diffraction optical element 40a, a second diffraction optical element 40b, and a third diffraction optical element 40c. The diffractive optical elements 40a, 40b, and 40c are provided corresponding to the laser light sources 20a, 20b, and 20c that oscillate the laser light. According to this example, even when the laser light sources 20a, 20b, 20c oscillate laser light in different wavelength ranges, the diffractive optical elements 40a, 40b, 40c have different wavelength ranges generated by the corresponding laser light. It is possible to diffract the laser beam with high efficiency.

The light emitted from each of the plurality of laser light sources 20a, 20b, 20c is diffracted by the diffractive optical elements 40a, 40b, 40c corresponding to each laser light source, and then illuminates at least a partially overlapping region. In particular, in the illustrated example, the light emitted from each of the plurality of laser light sources 20a, 20b, 20c is diffracted by the diffractive optical elements 40a, 40b, 40c corresponding to each laser light source, and then the same illuminated region Z Illuminate. More precisely, the diffracted light diffracted by the diffractive optical elements 40a, 40b, 40c illuminates only the entire area of the same illuminated region Z. The diffracted light from each of the diffractive optical elements 40a, 40b, and 40c illuminates only the illuminated area Z over the entire area, thereby producing uneven brightness and uneven color in the illuminated area Z. It can be made inconspicuous.

In the examples shown in FIGS. 1 and 2, the plurality of diffractive optical elements 40 are arranged in a first direction da perpendicular to the longitudinal direction dl of the illuminated region Z. Further, the first direction da in which the plurality of diffractive optical elements 40 are arranged is parallel to the normal direction nd to the surface pl as a flat surface on which the illuminated region Z is located. In particular, in the illustrated example, the first direction da in which the plurality of diffractive optical elements 40 are arranged is in the vertical direction perpendicular to the horizontal direction. That is, in the illustrated specific example, diffracted light from a plurality of diffractive optical elements 40 arranged vertically above the ground or water surface illuminates a horizontal plane pl such as the ground or water surface, and is placed on the horizontal plane pl. The illuminated area Z is formed. The plurality of diffractive optical elements 40 are arranged so as to be displaced in the vertical direction.

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

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

Each diffractive optical element 40 can be manufactured by using, for example, scattered light from an actual scattering plate as object light. More specifically, when the hologram photosensitive material, which is the base of the diffractive optical element 40, is irradiated with reference light and object light composed of coherent light having mutual interference, interference fringes due to the interference of these lights become the hologram photosensitive material. The diffractive optical element 40 is manufactured in the above. As the reference light, laser light which is coherent light is used, and as the object light, for example, scattered light from an isotropic scattering plate which can be obtained at a low price is used.

By irradiating the diffractive optical element 40 with laser light so that the optical path of the reference light used in the production of the diffractive optical element 40 travels in the opposite direction, the object light used in the production of the diffractive optical element 40 A reproduced image of the scattering plate is generated at the position where the scattering plate is originally arranged. If the scattering plate that is the source of the object light used when manufacturing the diffractive optical element 40 has uniform surface scattering, the reproduced image of the scattering plate obtained by the diffractive optical element 40 also has uniform surface illumination. The region where the reproduced image of the scattering plate is generated can be defined as the illuminated region Z.

Further, the complex interference fringe pattern formed on each diffractive optical element 40 is reproduced along with the wavelength and incident direction of the planned reproduction illumination light, instead of being formed by 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 power image. The diffractive optical element 40 thus obtained is also called a computer-generated hologram (CGH). For example, when the lighting device 10 is used to illuminate an illuminated area Z having a certain size on the ground or water surface, it is difficult to generate object light, and a computer composite hologram is diffracted by an optical element. It is preferable to use it as 40.

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

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

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

The laser light emitted from each laser light source 20 first enters the corresponding shaping optical system 30. The shaping optical system 30 magnifies the laser light emitted from the laser light source 20. That is, the shaping optical system 30 shapes the laser beam so that the region occupied by the light in the cross section orthogonal to the optical axis expands. In the illustrated example, the shaping optical system 30 includes a first shaping optical system 30a, a second shaping optical system 30b, and a third shaping optical system 30c separately provided corresponding to the respective laser light sources 20a, 20b, 20c. Includes. Each shaping optical system 30 has a lens 31 and a collimating lens 32. As shown in FIG. 1, the lens 31 of the shaping optical system 30 diverges the laser light emitted from the laser light source 20 and converts it into a divergent luminous flux. Then, the collimating lens 32 of the shaping optical system 30 collimates the divergent luminous flux into a parallel luminous flux.

The laser beam shaped by the shaping optical system 30 then goes to the diffractive optical element 40. The diffractive optical element 40 includes a first diffractive optical element 40a, a second diffractive optical element 40b, and a third diffractive optical element 40c, which are separately provided corresponding to the laser light sources 20a, 20b, and 20c. Each diffractive optical element 40 records interference fringes corresponding to the central wavelength of the laser light emitted from the corresponding laser light source 20, and diffracts the laser light incident from a certain direction in a desired direction with high efficiency. Can be done. In the illustrated example, each diffractive optical element 40 diffuses over the same illuminated area Z located on a horizontal plane pl such as the ground or a water surface.

As a result, the illuminated region Z is independent due to the superposition of the laser light emitted from the first laser light source 20a, the laser light emitted from the second laser light source 20b, and the laser light emitted from the third laser light source 20c. The illuminated area Z can be illuminated with a color that cannot be reproduced only by the laser light emitted from the laser light source. Here, the illumination colors are the radiation bundle of the laser light emitted from the first laser light source 20a, the radiation bundle of the laser light emitted from the second laser light source 20b, and the radiation bundle of the laser light emitted from the third laser light source 20c. In other words, the desired color can be obtained by adjusting the emission bundle of the laser light emitted by adjusting the output of each laser light source.

By the way, in the illuminating device 10 described here, the optical path of the laser light emitted from the laser light source 20 is adjusted by the diffractive optical element 40 to illuminate the illuminated region Z. One of the advantages of using the diffractive optical element 40 is that the light energy density of the light from the light source device 15, for example, the laser light can be reduced by diffusion. Further, one of the other advantages is that the diffractive optical element 40 can be used as a directional surface light source. That is, when the laser beam is directly viewed with the human eye from within the illuminated area Z, it is not a point light source but a surface light source having the size of the diffractive optical element 40. Therefore, the laser beam of the same radiation bundle is converted into illumination by a light source emitted from a wider light emitting surface through the diffraction optical element 40, and the same illuminance distribution is compared with illumination by a point light source (lamp light source). The brightness at each position on the light source surface, that is, the power density, can be reduced to achieve the above. As a result, by using the diffractive optical element 40, it is possible to contribute to the improvement of the safety of the laser light when the laser light source 20 is used as the light source.

When the area of the diffractive optical element 40 is increased, the incident region of the laser light from the light source device 15, that is, the spot region can be widened. The laser light incident on the diffractive optical element 40 is diffracted by the diffractive optical element 40 and emitted from the entire incident region on the diffractive optical element 40 toward the illuminated region Z. Therefore, by increasing the areas of the entrance surface and the exit surface of the diffractive optical element 40, the power density at each position on the diffractive optical element 40 can be reduced.

However, on the other hand, if the area of the diffractive optical element 40 is increased, the size of the lighting device 10 is increased. The problem of increasing the size of the lighting device becomes more serious in the above-mentioned lighting device 10 that illuminates with a specific color by additive color mixing using light in a plurality of wavelength ranges.

In the present embodiment, measures are taken to achieve both a decrease in power density, which can be said to be in a trade-off relationship, and a miniaturization of the lighting device 10. That is, in the present embodiment, the area of the diffractive optical element 40 corresponding to the laser light source 20 is changed according to the size of the radiation bundle of the laser light emitted by the laser light source 20, and the power density is lowered and the lighting device is used. We are trying to achieve both miniaturization of 10. A specific configuration will be described below.

The "radiant flux of laser light" here does not mean the maximum radiant flux that can be emitted by a laser light source. In other words, the "radiation bundle of laser light" here does not mean the ability of the laser light source. The "radiant flux of laser light" here means a radiant flux of laser light actually emitted from a laser light source whose output is adjusted according to the lighting application.

First, among the laser beams emitted by the plurality of laser light sources 20 included in the lighting device 10, the area of the diffractive optical element corresponding to the laser light source that emits the laser light that is the smallest radiation bundle is the largest radiation bundle. It is smaller than the area of the diffractive optical element corresponding to the laser light source that emits the laser beam. In the illustrated example, the emission bundle of the laser light in the red wavelength region emitted from the first laser light source 20a is the largest, and the emission bundle of the laser light in the blue wavelength region emitted from the third laser light source 20c. However, it is the smallest. Therefore, the area of the entrance surface and the exit surface of the third diffractive optical element 40c corresponding to the third laser light source 20c that oscillates the laser light that is the minimum radiation bundle oscillates the laser light that is the maximum radiation bundle. It is smaller than the area of the entrance surface and the exit surface of the first diffraction optical element 40a corresponding to the laser light source 20a.

As described above, if the emission region on the emission surface of the diffractive optical element 40 is wide, the power density can be reduced accordingly. Therefore, by considering the size of the radiant flux of the laser light source 20 and determining the size of the exit surface of the diffractive optical element 40 and the incident surface that is usually in the same region as the exit surface, the illuminating device 10 can be used. Safety can be imparted. On the other hand, when the emission bundle of the laser light emitted from the third laser light source 20c is smaller than the emission bundle of the laser light emitted from the first laser light source 20a, the power density at the position on the diffractive optical element is lowered. From such a viewpoint, it is not necessary to increase the area of the third diffractive optical element 40c corresponding to the third laser light source 20c to the same extent as the area of the first diffractive optical element 40a corresponding to the first laser light source 20a. By reducing the area of the incident surface and the exit surface of the third diffractive optical element 40c, in other words, by reducing the planar shape of the third diffractive optical element 40c, it is possible to avoid unnecessary enlargement. The device 10 can be miniaturized.

Further, it is assumed that the emission bundle of the laser light emitted from the minimum third laser light source 20c is W _min [W] and the emission bundle of the laser light emitted from the maximum first laser light source 20a is W _max [W]. , The area of the third diffraction optical element 40c corresponding to the third laser light source 20c that emits the laser light having the smallest radiation bundle A _min [mm ² ], and emits the laser light having the largest radiation bundle. The area A _max [mm ² ] of the first diffraction optical element 40a corresponding to the first laser light source 20a satisfies the following relationship.
A _max × (W _min / W _max ) ≦ A _min

That is, it is assumed that the entire area of the first diffractive optical element 40a is effectively utilized, that is, the laser beam is spread over the entire area of the incident surface of the first diffractive optical element 40a and is incident at a uniform intensity. On the premise, the magnitude of the power density at each position on the first diffraction optical element 40a is expressed using (W _max / A _max ) as an index. Therefore, the area A _max of the first diffraction optical element 40a should be determined so that the value of this index (W _max / A _max ) is sufficient. As described above, the third diffractive optical element 40c has a smaller area than the first diffractive optical element 40a, but the power density at each position on the third diffractive optical element 40c is on the first diffractive optical element 40a. It is preferable to set the power density or less at each position of. The magnitude of the power density at each position on the third diffractive optical element 40c on which the laser beam that becomes the minimum radiation bundle is incident is expressed with (W _min / A _min ) as an index. When the area A _{min of} the third diffractive optical element 40c satisfies the above-mentioned conditions and is "A _max × (W _min / W _max )" or more, at each position on the third diffractive optical element 40c. The power density of the above can be set to be equal to or less than the power density at each position on the first diffraction optical element 40a. That is, when the above conditions are satisfied, the area of the first diffractive optical element 40a corresponding to the first laser light source 20a having the maximum radiant flux that increases the area relatively is set to the minimum necessary size. At the same time, it is possible to sufficiently reduce the power density of the third diffractive optical element 40c corresponding to the third laser light source 20c having the smallest radiant flux that is relatively miniaturized.

Further, in the present embodiment, the area of the diffractive optical element 40 corresponding to one arbitrarily selected laser light source 20 is the other laser light source 20 having a radiation bundle larger than that of the one laser light source 20. It is less than or equal to the area of the diffractive optical element 40 corresponding to. That is, as the radiant flux of the laser light source 20 becomes smaller, the area of the corresponding diffractive optical element 40 becomes smaller. In other words, as the radiant flux of the laser light source 20 increases, the area of the corresponding diffractive optical element 40 increases.

In the illustrated example, the emission bundle of the laser light emitted from the second laser light source 20b is smaller than the emission bundle of the laser light emitted from the first laser light source 20a, and the emission of the laser light emitted from the third laser light source 20c. It's bigger than a bunch. That is, the radiant flux of the laser light becomes smaller in the order of the first laser light source 20a, the second laser light source 20b, and the third laser light source 20c. As shown in FIGS. 2 and 3, in the illustrated example, the area is reduced in the order of the first diffraction optical element 40a, the second diffraction optical element 40b, and the third diffraction optical element 40c. According to such an illuminating device 10, the area of the diffractive optical element 40 can be effectively reduced while the power density at each position on each diffractive optical element 40 is sufficiently reduced.

Further, ideally, the radiation flux W _a laser beam emitted from the first laser source _20a, radiant flux W _b of the laser light emitted from the second laser light source _20b, the laser light emitted from the third laser light source 20c radiant flux _{W c,} the area _{a a} of the first diffractive optical element 40a, the area _{a b} and area _{a c} of the third diffractive optical element 40c of the second diffractive optical element 40b preferably satisfies the following relationship.
_{W a: W b: W c} = A a: A b: A c As an example, in the illumination device 10 is illustrated, the laser beam of radiant flux _{W a} emitted from the first laser source 20a, the second laser light source radiant flux _{W c} of the exit laser beam from a radiation flux _{W b} and the third laser light source 20c of the injection laser beam from 20b is 7: 4: has a two relationships. The area ratio of the first diffraction optical element 40a, the second diffraction optical element 40b, and the third diffraction optical element 40c is 7: 4: 2. As shown in FIG. 2, the first diffraction optical element 40a, the second diffraction optical element 40b, and the third diffraction optical element 40c have the same length in the second direction db parallel to the width direction dw of the illuminated region Z. Has On the other hand, as shown in FIG. 3, the first diffraction optical element 40a, the second diffraction optical element 40b, and the third diffraction optical element 40c have a length of 7: 4: 2 along the first direction da. Oil. According to such a lighting device 10, the power densities can be made uniform among the diffractive optical elements 40. Therefore, by setting this power density to a sufficient value, the area of the plurality of diffractive optical elements 40 included in the lighting device 10 can be reduced.

In the above-described embodiment described above, the lighting device 10 includes a plurality of laser light sources 20 that emit laser light of different radiation bundles, and diffractive optical elements provided corresponding to each of the plurality of laser light sources. It has 40 and. The area of the diffractive optical element 40 corresponding to the laser light source 20 that emits the laser light that becomes the minimum radiation bundle is the area of the diffractive optical element 40 that corresponds to the laser light source 20 that emits the laser light that becomes the maximum radiation bundle. Is smaller than. That is, in the lighting device 10, the area of the corresponding diffractive optical element 40 is changed according to the size of the radiant flux of the laser light emitted by the laser light source 20. Therefore, the power density at each position of each diffractive optical element 40 can be effectively reduced, and the area of the diffractive optical element 40 corresponding to the laser light source 20 that emits laser light having a low radiant flux is unnecessary. It is possible to effectively avoid the increase. As a result, the lighting device 10 can be effectively miniaturized while ensuring safety. In particular, as in the illustrated example, when the illuminated area Z is illuminated with a specific color by additive color mixing, the laser light emitted by each laser light source 20 corresponding to the wavelength range of the generated laser light is emitted. The bundle will be adjusted accordingly. The lighting device 10 according to the present embodiment is particularly useful when the laser light source 20 in a plurality of wavelength ranges is included in this way.

Further, in the above-described embodiment, if the minimum radiant flux is W _min [W] and the maximum radiant flux is W _max [W], it corresponds to the laser light source 20 that emits the laser light that is the minimum radiant flux. The area A _min [mm ² ] of the diffractive optical element 40 and the area A _max [mm ² ] of the diffractive optical element 40 corresponding to the laser light source 20 that emits the laser light that becomes the maximum radiant flux have the following relationship. It is designed to meet.
A _max × (W _min / W _max ) ≦ A _min According to this lighting device 10, at each position of the diffractive optical element 40 having a small area corresponding to the laser light source 20 that emits the laser light that is the smallest radiation bundle. The power density can be reduced to less than or equal to the power density at each position of the large-area diffractive optical element 40 corresponding to the laser light source 20 that emits the laser light that is the maximum radiation bundle. That is, the power density at each position of the diffractive optical element 40 having a small area can be sufficiently reduced, whereby the lighting device 10 can be more effectively miniaturized while ensuring safety. Become.

Further, in the above-described embodiment, the area of the diffractive optical element 40 corresponding to one arbitrarily selected laser light source 20 is a laser beam having a radiation bundle larger than the laser beam emitted by the one laser light source 20. It is smaller than the area of the diffractive optical element 40 corresponding to the other laser light source 20 that emits the light. According to the lighting device 10, the size of the diffractive optical element 40 corresponding to each laser light source 20 changes sequentially according to the size of the radiant flux of the laser light emitted by the laser light source 20. Therefore, the power density can be made uniform to some extent between the diffractive optical elements 40. As a result, the area of the diffractive optical element 40 can be minimized.

Further, in the above-described embodiment, the lighting device 10 further includes a shaping optical system 30 that magnifies the laser light emitted from the plurality of laser light sources 20 and guides the laser light to the diffractive optical element 40. According to the lighting device 10, the light emitted from the laser light source 20 is magnified and then incident on the diffractive optical element 40. Therefore, the power density at each position of the diffractive optical element 40 can be effectively reduced, and the safety can be improved.

It is possible to make various changes 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 codes as those used for the corresponding parts in the above-described embodiment are used for the parts that can be configured in the same manner as in the above-described embodiment, and duplicated. The explanation to be performed is omitted.

For example, in the above-described embodiment, an example is shown in which separate shaping optical systems 30 are prepared for each of the plurality of laser light sources 20, but the present invention is not limited to this. Any one or more of the elements of the shaping optical system 30 or the lens 31 and the collimating lens 32 included in the shaping optical system 30 may be shared among the plurality of laser light sources 20.

Further, in the above-described embodiment, the lighting device 10 has shown an example of illuminating an elongated region, but the present invention is not limited to this. The lighting device 10 may function as a device that illuminates an area having a predetermined contour and therefore displays a predetermined contour. As a predetermined contour, for example, an arrow or the like can be exemplified.

dl Longitudinal direction dw Width direction da 1st direction db 2nd direction Z Illuminated area 10 Illumination device 15 Light source device 20 Laser light source 20a 1st laser light source 20b 2nd laser light source 20c 3rd laser light source 30 Orthopedic optical system 30a 1st shaping Optical system 30b Second shaping optical system 30c Third shaping optical system 31 Lens 31a First lens 31b Second lens 31c Third lens 32 Collimating lens 32a First collimating lens 32b Second collimating lens 32c Third collimating lens 40 Diffractive optical element 40a First diffraction optical element 40b Second diffraction optical element 40c Third diffraction optical element

Claims (1)

Multiple laser light sources that emit laser light from different radiant fluxes,
A diffractive optical element provided corresponding to each of the plurality of laser light sources is provided.
The area of the diffractive optical element corresponding to the laser light source that emits the laser light that is the smallest radiation bundle is smaller than the area of the diffractive optical element that corresponds to the laser light source that emits the laser light that is the largest radiation bundle. apparatus.

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