Lighting device

Abstract

Provided is a lighting device capable of creating a brighter image by multiplexing with a simple configuration without using an additional member for multiplexing.　A lighting device (10) comprises: a diffraction optical element (50) for receiving a laser beam that has a wavelength in a visible region and converting the laser beam into a light beam group corresponding to a dot pattern group projected on a projection surface (S); and optical systems (LD1, LD2) for causing a first laser beam (Ray1LD1) and a second laser beam (Ray1LD2) to be incident on the diffraction optical element, said first laser beam having a wavelength in the visible region and being parallel light to be converted to a first light beam group (Ray2LD1) corresponding to a first dot pattern group, said second laser beam having a wavelength in the visible region and being parallel light to be converted to a second light beam group (Ray2LD2) corresponding to a second dot pattern group.

Description

lighting equipment

[0001] The present disclosure relates to a lighting device.

[0002] There is known an illumination device (e.g., a projector) that uses multiple light sources that emit light of different wavelengths, such as RGB light sources, and combines the light emitted by each light source using a dichroic mirror, then diffuses it using a homogenizer, and forms an image using a light modulation element such as LCOS (Liquid Crystal On Silicon) (see, for example, Non-Patent Document 1).

[0003] Optical Technology Information Magazine "Light Edge" No. 37 (Special Feature: Ushio's New Initiatives, Part 2) [Retrieved February 19, 2024], Internet <URL: https: / / www.ushio.co.jp / jp / technology / lightedge / 201206 / 100438.html>

[0004] However, the illumination device described in Non-Patent Document 1 requires an additional component (dichroic mirror) for combining the beams, which increases the number of components and increases costs.

[0005] The present disclosure has been made to solve such problems, and aims to provide an illumination device that can combine light beams with a simple configuration to create a brighter image without using any additional components for combining light beams.

[0006] The lighting device according to the present disclosure includes a diffractive optical element that receives laser light of a wavelength in the visible range and converts the laser light into a group of rays corresponding to a group of dot patterns to be projected onto a projection surface, and an optical system that causes first laser light of a wavelength in the visible range, which is parallel light that is converted into a first group of rays corresponding to a first group of dot patterns, and second laser light of a wavelength in the visible range, which is parallel light that is converted into a second group of rays corresponding to a second group of dot patterns, to be incident on the diffractive optical element.

[0007] With this configuration, it is possible to combine the beams with a simple configuration and create a brighter image without using any additional components for combining the beams.

[0008] In addition, in the above-mentioned lighting device, the first dot pattern group and the second dot pattern group may be formed on the projection surface shifted from each other by a predetermined distance in a predetermined direction by making the second laser light incident on the diffractive optical element at an incident angle different from the incident angle of the first laser light on the diffractive optical element.

[0009] In the above lighting device, the first dot pattern group may be a pattern in which dots are projected at a first dot pitch, and the predetermined distance may be 1 / 2 of the first dot pitch.

[0010] In the above illumination device, an incident angle of the second laser light with respect to the diffractive optical element may be half the diffraction angle of the first laser light.

[0011] In addition, in the above-mentioned lighting device, the first dot pattern group and the second dot pattern group may be formed in an overlapping state by making the second laser light incident on the diffractive optical element at the same incident angle as the incident angle of the first laser light on the diffractive optical element.

[0012] In the illumination device, the first laser light and the second laser light may have the same wavelength.

[0013] In the lighting device, the first laser light and the second laser light may have different wavelengths.

[0014] The above-described illumination device may further include a diffractive optical element onto which n (n is an integer of 2 or greater) laser beams are incident, the diffractive optical element converting the incident laser beams into a dot pattern group, the diffraction angles of the dot pattern groups being the same for each laser beam, and the angles of incidence of the n laser beams with respect to the diffractive optical element differ from one another by 1 / n times the diffraction angles.

[0015] The present disclosure makes it possible to provide an illumination device that can combine light beams with a simple configuration to create a brighter image without using any additional components for combining light beams.

[0016] 2 is a schematic diagram of the illumination device 10. FIG. 3 is a simplified view of the laser light sources LD (LD1 to LD4) as seen from the direction of the arrow AR1 in FIG. 1. FIG. 4 is an enlarged view of the diffractive optical element 50 as seen from the direction of the arrow AR1 in FIG. 3A. FIG. 5 is a cross-sectional view taken along IIIB-IIIB in FIG. 3A. FIG. 6 is an example of a group of dot patterns DP projected onto a projection surface S. FIG. 7 is a cross-sectional view of the laser light Ray1 in the VA-VA cross-section in FIG. 2. ＬＤ１ , Ray1 ＬＤ２ 2 is a diagram showing the optical path of the laser beam Ray1 in the VB-VB cross section of FIG. ＬＤ３ , Ray1 ＬＤ４ 2 is a diagram showing the optical path of the laser beam Ray1 in the VC-VC cross section of FIG. ＬＤ１ , Ray1 ＬＤ３ 2 is a diagram showing the optical path of the laser beam Ray1 in the VD-VD cross section of FIG. ＬＤ２ , Ray1 ＬＤ４ 1 is an optical path diagram of the dot pattern DP projected on the projection surface S. FIG. 2 is an example of a dot pattern DP projected on the projection surface S. FIG. 3 is an example of a dot pattern DP projected on the projection surface S. FIG. 4 is an enlarged arrow view of the aperture 60 as seen from the direction of the arrow AR1 in FIG. 1. FIG. 5 is an example of a dot pattern DP (DP ＬＤ１ ~DP ＬＤ４ 10 is a schematic diagram of a lighting device 10 (modification example).

[0017] Hereinafter, an illumination device 10 (image forming device) according to an embodiment of the present disclosure will be described with reference to the accompanying drawings. Corresponding components in the various drawings are designated by the same reference numerals, and redundant description will be omitted.

[0018] Fig. 1 is a schematic diagram of the illumination device 10. Fig. 2 is a diagram (simplified diagram) of the laser light sources LD (LD1 to LD4) as seen in the direction of arrow AR1 in Fig. 1.

[0019] As shown in FIGS. 1 and 2, the lighting device 10 includes a plurality of laser light sources LD (LD1 to LD4). The plurality of laser light sources LD are, for example, a plurality of laser light sources that emit laser light of the same wavelength in the visible range. The laser light Ray1 (Ray1) emitted by each of the plurality of laser light sources LD is ＬＤ１ ~Ray1 ＬＤ４The laser light emitted by the laser light source LD1 is converted into parallel light by passing through a plurality of lenses 30 provided corresponding to the plurality of laser light sources LD, and then enters a diffractive optical element (DOE) 50. Hereinafter, the laser light emitted by the laser light source LD1 is referred to as laser light Ray1. ＬＤ１ Similarly, the laser light emitted from the laser light sources LD2 to LD4 is written as laser light Ray1. ＬＤ２ ~Ray1 ＬＤ４ Hereinafter, an example using four laser light sources LD1 to LD4 will be described, but the present invention is not limited to this. Two or more laser light sources, that is, a plurality of laser light sources, may be used.

[0020] Fig. 3A is an enlarged view of the diffractive optical element 50 in Fig. 1 as seen from the direction of arrow AR1, and Fig. 3B is a cross-sectional view taken along the line IIIB-IIIB of Fig. 3A. The cross-sectional view taken along the line BB of Fig. 3A is similar to the cross-sectional view taken along the line IIIB-IIIB.

[0021] The diffractive optical element 50 includes a microlens array. It receives laser light Ray1 emitted by each laser light source LD and converted into parallel light by the lens 30, and converts (diffracts) the laser light Ray1 into a group of rays Ray2 corresponding to the dot pattern group to be projected onto the projection surface S. That is, the diffractive optical element 50 diffracts and splits the incident laser light Ray1 in the vertical, horizontal, and vertical directions. The group of rays Ray2 becomes a bundle of parallel light beams with multiple directions. For example, the diffractive optical element 50 may be a diffractive optical element under the name "ardisia" manufactured by Scivax. For example, the diffractive optical element 50 may be one described in Japanese Patent No. 7061823. However, the diffractive optical element 50 may have any configuration as long as it receives laser light (parallel light) and converts (diffracts) the laser light into a group of rays corresponding to the dot pattern group to be projected onto the projection surface S. For example, it may be a general diffraction grating with a groove structure. Hereinafter, the laser light Ray1 will be referred to as a bundle of parallel light beams. ＬＤ１ The transformed ray group corresponding to ＬＤ１ Laser light Ray1 ＬＤ２ ~Ray1 ＬＤ４ Similarly, the ray group transformed corresponding to ＬＤ２~Ray2 ＬＤ４ It is written as follows.

[0022] 3A and 3B, the microlens array of the diffractive optical element 50 includes a plurality of lenses 51 arranged two-dimensionally in the X and Y directions. While FIGS. 3A and 3B show an example in which the lenses 51 are provided on the incident side of the diffractive optical element 50 (the incident side of the laser beam Ray1), the present invention is not limited to this. The lenses 51 may be provided on at least one of the incident side and the exit side of the diffractive optical element 50 (the incident side of the laser beam Ray1 and the exit side of the laser beam Ray1).

[0023] FIG. 4 shows an example of a group of dot patterns DP projected onto the projection surface S. Hereinafter, laser light Ray1 ＬＤ１ (Ray group Ray2 ＬＤ１ ) is the dot pattern DP ＬＤ１ Laser light Ray1 ＬＤ２ ~Ray1 ＬＤ４ (Ray group Ray2 ＬＤ２ ~Ray2 ＬＤ４ Similarly, the dot pattern DP ＬＤ２ ~DP ＬＤ４ It is written as follows.

[0024] The dot pattern is, for example, circular (see FIG. 4), but is not limited to this and may be rectangular or another shape.

[0025] It should be noted that if the pitch P of the lenses 51 (see FIG. 3B ) is too small compared to the wavelength λ of the laser light emitted by the laser light source LD, diffraction will be difficult to generate. Therefore, as long as there are enough lenses 51 included within the distribution angle of the laser light to generate diffraction, the pitch P should be sufficiently larger than the wavelength λ of the laser light, for example, 5 times or more, and preferably 10 times or more.

[0026] The material of the diffractive optical element 50 is, for example, PDMS with a refractive index of 1.53.

[0027] Hereafter, laser light Ray 1 ＬＤ１ ~Ray1 ＬＤ４ (Ray group Ray2 １Ｄ２ ~Ray2 ＬＤ４Hereinafter, it is assumed that the wavelength of the laser light emitted from each of the laser light sources LD1 to LD4 is 510 nm, the beam diameter of the laser light Ray1 (parallel light) incident on the diffractive optical element 50 is 5 mm, and the pitch P of the lenses 51 is 25.5 μm.

[0028] FIG. 5A shows the laser beam Ray1 in the VA-VA cross section of FIG. ＬＤ１ , Ray1 ＬＤ２ 5B is a diagram showing the optical path of the laser beam Ray1 in the VB-VB cross section of FIG. ＬＤ３ , Ray1 ＬＤ４ 5C is a diagram showing the optical path of the laser beam Ray1 in the VC-VC cross section of FIG. ＬＤ１ , Ray1 ＬＤ３ 5D is a diagram showing the optical path of the laser beam Ray1 in the VD-VD cross section of FIG. ＬＤ２ , Ray1 ＬＤ４ 6A to 6C are examples of a group of dot patterns DP projected onto the projection surface S.

[0029] Laser light Ray1 is incident on the diffractive optical element 50. ＬＤ１ When the diffractive optical element 50 converts the light beams into a group of rays Ray2, ＬＤ１ As a result, a dot pattern DP shown in FIG. ＬＤ１ A group is formed (projected). The intervals L1 and L2 between the dots are, for example, approximately 20 mm at a position 1 m away from the diffractive optical element 50. Note that FIG. 4 (and also FIGS. 6A to 6C) is an example (part) of a dot pattern, and in reality, a larger number of dot patterns than this are formed.

[0030] Laser light Ray1 to the diffractive optical element 50 ＬＤ１ The angle of incidence of the ray group Ray2 is 0 degrees on both the VA-VA cross section and the VC-VC cross section (see FIGS. 5A and 5C). In this case, the diffraction angle θ1 is 1.1458 degrees. ＬＤ１ The zeroth-order light Ray 2 that constitutes ＬＤ１＿０ and primary light Ray 2 ＬＤ１＿１ The angle between the two.

[0031] Similarly, the laser beam Ray1 is incident on the diffractive optical element 50. ＬＤ２is incident on the diffractive optical element 50, the ray group Ray2 is converted by the diffractive optical element 50. ＬＤ２ As a result, a dot pattern DP shown in FIG. ＬＤ１ Dot pattern DP similar to the group ＬＤ２ A group is formed (projected).

[0032] However, as shown in FIG. 6A, the dot pattern DP ＬＤ２ The group is a dot pattern DP ＬＤ１ The dot pattern DP in FIG. 6A is positioned at a predetermined distance from the group (the downward direction in FIG. 6A). ＬＤ１ The electrodes are formed with a shift of 1 / 2 the distance L2 between them.

[0033] This is because the laser beam Ray1 is incident on the diffractive optical element 50. ＬＤ２ The incident angle and incident position of the laser beam Ray1 on the diffractive optical element 50 are ＬＤ１ This is because the incident angle and incident position are different from those of the light source.

[0034] That is, the laser beam Ray1 to the diffractive optical element 50 ＬＤ２ The incident angle of the laser beam Ray1 on the diffractive optical element 50 is angle θ2 on the VA-VA cross section (see FIG. 5A) and 0 degrees on the VD-VD cross section (see FIG. 5D). The angle θ2 is half the diffraction angle θ1. When the diffraction angle θ1 is 1.1458 degrees, the angle θ2 is approximately 0.573 degrees. The laser light source LD2 directs the laser beam Ray1 onto the diffractive optical element 50. ＬＤ２ The incident angle of the light beam is set to θ2. ＬＤ２ is the reference axis (optical axis AX of the laser light source LD1) ＬＤ１ ) is arranged at an angle θ2.

[0035] In addition, the laser beam Ray1 to the diffractive optical element 50 ＬＤ２ The incident position of the laser beam Ray1 on the diffractive optical element 50 in the VA-VA cross section is ＬＤ１ The incident position is shifted by a distance H1 from the incident position (see FIG. 5A). H1 is, for example, 40 mm.

[0036] As described above, the laser beam Ray1 is incident on the diffractive optical element 50. ＬＤ２ The incident angle and incident position of the laser beam Ray1 on the diffractive optical element 50 are ＬＤ１As a result of the different incident angles and incident positions, the dot pattern DP ＬＤ２ The group is a dot pattern DP ＬＤ１ The dot pattern DP in FIG. 6A is positioned at a predetermined distance from the group (the downward direction in FIG. 6A). ＬＤ１ The angle θ2 and the distance H1 may be adjusted as appropriate.

[0037] Similarly, the laser beam Ray1 is incident on the diffractive optical element 50. ＬＤ３ is incident on the diffractive optical element 50, the ray group Ray2 is converted by the diffractive optical element 50. ＬＤ３ As a result, a dot pattern DP shown in FIG. ＬＤ１ Dot pattern DP similar to the group ＬＤ３ A group is formed (projected).

[0038] However, as shown in FIG. 6B, the dot pattern DP ＬＤ３ The group is a dot pattern DP ＬＤ１ The dot pattern DP in FIG. 6B is positioned at a predetermined distance from the group in a predetermined direction (to the right in FIG. 6B). ＬＤ１ The electrodes are formed with a shift of 1 / 2 the distance L1 between them.

[0039] This is because the laser beam Ray1 is incident on the diffractive optical element 50. ＬＤ３ The incident angle and incident position of the laser beam Ray1 on the diffractive optical element 50 are ＬＤ１ This is because the incident angle and incident position are different from those of the light source.

[0040] That is, the laser beam Ray1 to the diffractive optical element 50 ＬＤ３ The incident angle of the ray group Ray2 is 0 degrees on the VB-VB cross section (see FIG. 5B) and is an angle θ6 on the VC-VC cross section (see FIG. 5C). The angle θ6 is half the diffraction angle θ5. The diffraction angle θ5 is the angle of the ray group Ray2. ＬＤ１ The zeroth-order light Ray 2 that constitutes ＬＤ１＿０ and primary light Ray 2 ＬＤ１＿１ When the diffraction angle θ5 is 1.1458 degrees, the angle θ6 is approximately 0.573 degrees (see FIG. 5C). ＬＤ３ The incident angle of the light beam is set to θ6. ＬＤ３is the reference axis (optical axis AX of the laser light source LD1) ＬＤ１ ) is arranged at an angle θ6.

[0041] In addition, the laser beam Ray1 to the diffractive optical element 50 ＬＤ３ The incident position of the laser beam Ray1 on the diffractive optical element 50 in the VC-VC cross section is ＬＤ１ The incident position is shifted by a distance H3 from the incident position (see FIG. 5C). H3 is, for example, 40 mm.

[0042] As described above, the laser beam Ray1 is incident on the diffractive optical element 50. ＬＤ３ The incident angle and incident position of the laser beam Ray1 on the diffractive optical element 50 are ＬＤ１ As a result of the different incident angles and incident positions, the dot pattern DP ＬＤ３ The group is a dot pattern DP ＬＤ１ The dot pattern DP in FIG. 6B is positioned at a predetermined distance from the group in a predetermined direction (to the right in FIG. 6B). ＬＤ１ The angle θ6 and the distance H3 may be adjusted as appropriate.

[0043] Similarly, the laser beam Ray1 is incident on the diffractive optical element 50. ＬＤ４ is incident on the diffractive optical element 50, the ray group Ray2 is converted by the diffractive optical element 50. ＬＤ４ As a result, a dot pattern DP shown in FIG. ＬＤ１ Dot pattern DP similar to the group ＬＤ４ A group is formed (projected).

[0044] However, as shown in FIG. 6C, the dot pattern DP ＬＤ４ The group is a dot pattern DP ＬＤ１ The dot pattern DP in FIG. 6C is positioned at a predetermined distance in a predetermined direction (rightward and downward in FIG. 6C) relative to the group. ＬＤ１ The distances L1 and L2 are offset from each other (half of the distance between the two).

[0045] This is because the laser beam Ray1 is incident on the diffractive optical element 50. ＬＤ４ The incident angle and incident position of the laser beam Ray1 on the diffractive optical element 50 are ＬＤ１ This is because the incident angle and incident position are different from those of the light source.

[0046] That is, the laser beam Ray1 to the diffractive optical element 50 ＬＤ４ The incident angle of the ray group Ray2 is angle θ4 on the VB-VB cross section (see FIG. 5B) and angle θ8 on the VD-VD cross section (see FIG. 5D). The angle θ4 is half the diffraction angle θ3. The diffraction angle θ3 is ＬＤ３ The zeroth-order light Ray 2 that constitutes ＬＤ３＿０ and primary light Ray 2 ＬＤ３＿１ (See FIG. 5B.) When the diffraction angle θ3 is 1.1458 degrees, the angle θ4 is approximately 0.573 degrees. On the other hand, the angle θ8 is half the diffraction angle θ7. The diffraction angle θ7 is the angle between the group of rays Ray2 and Ray3. ＬＤ２ The zeroth-order light Ray 2 that constitutes ＬＤ２＿０ and primary light Ray 2 ＬＤ２＿１ When the diffraction angle θ7 is 1.1458 degrees, the angle θ8 is approximately 0.573 degrees (see FIG. 5D). ＬＤ４ The incident angles of the light beams are set to angles θ4 and θ8. ＬＤ４ is the reference axis (optical axis AX of the laser light source LD1) ＬＤ１ ) are arranged at angles θ4 and θ8.

[0047] In addition, the laser beam Ray1 to the diffractive optical element 50 ＬＤ４ The incident position of the laser beam Ray1 on the diffractive optical element 50 in the VB-VB cross section is ＬＤ１ The laser beam Ray1 is shifted by a distance H2 from the incident position of the diffractive optical element 50 (see FIG. 5B). H2 is, for example, 40 mm. ＬＤ４ The incident position of the laser beam Ray1 on the diffractive optical element 50 in the VD-VD cross section is ＬＤ１ The incident position is shifted by a distance H4 from the incident position (see FIG. 5D). H4 is, for example, 40 mm.

[0048] As described above, the laser beam Ray1 is incident on the diffractive optical element 50. ＬＤ４ The incident angle and incident position of the laser beam Ray1 on the diffractive optical element 50 are ＬＤ１ As a result of the different incident angles and incident positions, the dot pattern DP ＬＤ４The group is a dot pattern DP ＬＤ１ The dot pattern DP in FIG. 6C is positioned at a predetermined distance in a predetermined direction (rightward and downward in FIG. 6C) relative to the group. ＬＤ１ The angles θ4 and θ8 and the distances H2 and H4 may be adjusted as appropriate.

[0049] As described above, the laser beam Ray1 (Ray1 ＬＤ１ ~Ray1 ＬＤ４ ) can be incident on the laser light sources LD1 to LD4, thereby forming a high-density, high-brightness dot pattern group with half the pitch (approximately 10 mm in this case) (see FIG. 6C ). In other words, by simply arranging the laser light sources LD1 to LD4 as described above, it is possible to obtain four times the luminous flux (four times the brightness) without using any additional components. Furthermore, by arranging additional laser light sources between the laser light sources, it is possible to obtain eight times the luminous flux (eight times the brightness). In this embodiment, the laser light sources LD (LD1 to LD4) arranged as described above are an example of the optical system of the present disclosure.

[0050] The group of rays Ray2 (Ray2) converted by the diffractive optical element 50 ＬＤ１ ~Ray2 ＬＤ４ ) enters the aperture 60. Instead of the aperture 60, a transmissive liquid crystal element may be used.

[0051] The aperture 60 is an optical filter that is disposed on the optical path of the group of rays Ray2 converted by the diffractive optical element 50 and includes an opaque region that does not transmit the group of rays Ray2 and a transmissive region that transmits visible light. The aperture 60 (opaque region) may be, for example, a dichroic filter.

[0052] Figure 7 is an enlarged view of aperture 60 as seen from the direction of arrow AR1 in Figure 1. In Figure 7, arrowed area A1 in aperture 60 represents an opaque area through which light rays Ray2 of a specific color (here, blue-green with a wavelength of 510 nm) do not pass. This opaque area is a filter area that reflects or absorbs light rays Ray2 of the specific color. Meanwhile, hatched area HT1 in aperture 60 represents a transmissive area through which all visible light passes.

[0053] In the illumination device 10 configured as described above, when the laser light sources LD (LD1 to LD4) are turned on, an image formed on the projection surface S will be described.

[0054] When the laser light source LD (LD1 to LD4) is turned on, the laser light Ray1 (Ray1) emitted from the laser light source LD (LD1 to LD4) ＬＤ１ ~Ray1 ＬＤ４ The laser beam Ray1 (Ray1) is converted into parallel light by passing through the lens 30, and then enters the diffractive optical element 50 (see FIGS. 5A to 5D). The diffractive optical element 50 converts the laser beam Ray1 (Ray1) converted into parallel light by passing through the lens 30 into the diffractive optical element 50. ＬＤ１ ~Ray1 ＬＤ４ ), the laser beam Ray1 (Ray1 ＬＤ１ ~Ray1 ＬＤ４ ) into a group of rays Ray2 (Ray2 ＬＤ１ ~Ray2 ＬＤ４ ) to

[0055] The group of rays Ray2 (Ray2) converted by the diffractive optical element 50 ＬＤ１ ~Ray2 ＬＤ４ ) does not pass through the arrow area A1 (non-transmitting area) of the aperture 60. On the other hand, the group of rays Ray2 (Ray2 ＬＤ１ ~Ray2 ＬＤ４ ) passes through the hatched area HT1 (transparent area) of the aperture 60. As a result, a plurality of dot patterns DP (DP ＬＤ１ ~DP ＬＤ４ ) is formed (projected) in a specific color (here, green with a wavelength of 510 nm). ＬＤ１ ~DP ＬＤ４ ) is an example of an image formed by the aperture 60. Note that a similar image is formed when a transmission type liquid crystal element is used instead of the aperture 60.

[0056] As described above, according to this embodiment, it is possible to create a brighter image by combining beams with a simple configuration without using any additional component for combining beams.

[0057] In addition, in the above embodiment, four laser light sources are used to project a dot pattern with four times the brightness, but the number of light sources can be increased or decreased depending on the desired projection brightness and dot density.

[0058] For example, in the above embodiment, the laser light sources are arranged in two rows and two columns in the X and Y directions, but this can be changed to an arrangement of three rows and three columns, for a total of nine laser light sources.

[0059] In the case of two rows and two columns, the angle of incidence on the diffractive optical element is shifted by half the diffraction angle, but in the case of three rows and three columns, the angle of incidence is shifted by one-third of the diffraction angle, so that the dot pattern groups corresponding to each laser light are projected with a shift of one-third of the distance between the dot patterns.

[0060] Next, a modified example will be described.

[0061] FIG. 9 is a schematic diagram of the illumination device 10 (modification).

[0062] As shown in FIG. 9 , a reflecting surface 70 may be disposed between the laser light sources LD (LD1 to LD4) and the diffractive optical element 50, which are arranged to face each other. A plurality of reflecting surfaces 70 are disposed corresponding to a plurality of laser light sources. In this modification, the laser light sources LD (LD1 to LD4) and the reflecting surfaces 70 arranged as described above are an example of the optical system of the present disclosure. Note that, as long as the laser light Ray1 can be incident on the diffractive optical element 50 as described above, any optical system may be used, not limited to the optical system of the above embodiment or the optical system of this modification.

[0063] This modification also provides the same effects as the above embodiment.

[0064] In the above embodiment, an example has been described in which a plurality of laser light sources LD (LD1 to LD4) that emit laser light of the same wavelength in the visible range are used as the plurality of laser light sources, but this is not limiting. For example, a plurality of laser light sources that emit laser light of different wavelengths in the visible range may be used as the plurality of laser light sources. In this way, when a plurality of laser light sources that emit laser light of different wavelengths in the visible range are used, an expensive multiplexing prism such as a dichroic mirror is not required.

[0065] In the above embodiment, the plurality of dot patterns DP (DP ＬＤ１ ~DP ＬＤ４ ) groups are formed on the projection surface S in a state where they are shifted from each other by a predetermined distance in a predetermined direction (see FIGS. 6A to 6C), but this is not limiting. For example, ＬＤ１ ~DP ＬＤ４ ) may be formed in a state where they overlap each other on the projection surface S. This can be realized, for example, by adjusting the angles of incidence θ2, θ4, θ6, and θ8 (the angles of the optical axes of the laser light sources LD1 to LD4 with respect to the reference axis) with respect to the diffractive optical element 50, and the distances H1, H2, H3, and H4 between the laser beams. For example, the angles of incidence θ2, θ4, θ6, and θ8 of the laser beam Ray1 with respect to the diffractive optical element 50 may be adjusted. ＬＤ１ This can be achieved by making the incident angle the same as that of the incident light (for example, 0 degrees).

[0066] All numerical values ​​shown in the above embodiments are merely examples, and it goes without saying that other appropriate numerical values ​​can be used. The above embodiments are merely examples in all respects. The present disclosure should not be interpreted as being limited by the description of the above embodiments. The present disclosure can be implemented in various other forms without departing from its spirit or main features.

[0067] This application claims priority based on Japanese Patent Application No. 2024-47779, filed March 25, 2024, the disclosure of which is incorporated herein by reference in its entirety.

[0068] REFERENCE SIGNS LIST 10: illumination device 30: lens 50: diffractive optical element 51: lens 60: aperture 70: reflecting surface A1: arrow area AX ＬＤ１ -AX ＬＤ４ ...Optical axis DP (DP ＬＤ１ -DP ＬＤ４ )...Dot pattern HT1...Hatched area LD (LD1-LD4)...Laser light source Ray1 (Ray1 ＬＤ１ -Ray 1 ＬＤ４ )...Laser light Ray2 (Ray2 ＬＤ１ -Ray 2 ＬＤ４ )...Ray group Ray2 ＬＤ１＿０ , Ray2 ＬＤ２＿０, Ray2 ＬＤ３＿０ ...0th order light Ray2 ＬＤ１＿１ , Ray2 ＬＤ２＿１ , Ray2 ＬＤ３＿１ ...Primary light S...Projection plane θ1, θ3, θ5, θ7...Diffraction angle θ2, θ4, θ6, θ8...Incidence angle

Claims

1. An illumination device comprising: a diffractive optical element that receives laser light with a wavelength in the visible range and converts the laser light into a group of rays corresponding to a group of dot patterns to be projected onto a projection surface; and an optical system that causes a first laser light with a wavelength in the visible range, which is parallel light that is converted into a first group of rays corresponding to a first group of dot patterns, and a second laser light with a wavelength in the visible range, which is parallel light that is converted into a second group of rays corresponding to a second group of dot patterns, to be incident on the diffractive optical element.

2. The lighting device of claim 1, wherein the first dot pattern group and the second dot pattern group are formed on the projection surface offset from each other by a predetermined distance in a predetermined direction by making the second laser light incident on the diffractive optical element at an incident angle different from the incident angle of the first laser light on the diffractive optical element.

3. The lighting device according to claim 2, wherein the first dot pattern group is a pattern in which dots are projected at a first dot pitch, and the predetermined distance is 1 / 2 of the first dot pitch.

4. The illumination device according to claim 3, wherein the angle of incidence of the second laser light on the diffractive optical element is half the angle of diffraction of the first laser light.

5. The lighting device described in claim 1, wherein the first dot pattern group and the second dot pattern group are formed in an overlapping state by making the second laser light incident on the diffractive optical element at the same incident angle as the incident angle of the first laser light on the diffractive optical element.

6. An illumination device according to any one of claims 1 to 5, wherein the wavelength of the first laser light and the wavelength of the second laser light are the same.

7. The lighting device according to claim 1 or 2, wherein the wavelengths of the first laser light and the second laser light are different from each other.

8. An illumination device comprising a diffractive optical element onto which n (n is an integer of 2 or greater) laser beams are incident, the diffractive optical element converts the incident laser beams into a dot pattern group, the diffraction angles of the dot pattern groups are the same for each laser beam, and the angles of incidence of the n laser beams on the diffractive optical element differ from one another by 1 / n times the diffraction angles.

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