Illumination device and projector

Abstract

To reduce speckle noise in a projection image in a projector comprising an illumination device.SOLUTION: An illumination device of the present invention comprises: a first light source that emits first light; a second light source that emits second light different in color from the first light; a light combining member that emits composite light of the first light and the second light; a diffusion device having a substrate with a diffusion surface that diffuses the composite light, and a driving device that rotates the substrate; a condensing element that is arranged between the light combining member and the diffusion device, and condenses the composite light on the diffusion surface; and a collimating element that collimates the composite light emitted from the diffusion device. The first light source has: a plurality of first light emitting elements that emit the first light in a first wavelength range; a plurality of second light emitting elements that emit the first light in a second wavelength range different from the first wavelength range; a first heat radiation member to which heat of the plurality of first light emitting elements is transferred; and a second heat radiation member to which heat of the plurality of second light emitting elements is transferred. The heat radiation capability of the first heat radiation member and the heat radiation capability of the second heat radiation member are different from each other.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an illumination device and a projector. [Background technology]

[0002] 2. Description of the Related Art In recent years, in order to improve the performance of projectors, lighting devices equipped with laser light sources that are light sources with a wide color gamut and high efficiency, and projectors equipped with such lighting devices have been proposed.

[0003] For example, in the projector disclosed in Patent Document 1, three color lights emitted from a red light source array having a laser light source that emits red light, a green light source array having a laser light source that emits green light, and a blue light source array having a laser light source that emits blue light are mixed by a color mixing optical system, and the mixed light enters a condenser lens and is collected toward a diffuser plate. In the projector disclosed in Patent Document 1, the collected mixed light passes through the diffuser plate, thereby reducing speckle noise that occurs in the projected image.

[0004] For example, the light source device disclosed in Patent Document 2 is applicable to lighting devices and projectors, and includes a plurality of first laser elements having the same emission wavelength and a plurality of second laser elements having the same emission wavelength, the emission wavelength of the second laser elements being shorter than the emission wavelength of the first laser elements. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2019-078906 A [Patent Document 2] Patent Publication No. 2021-057512 Summary of the Invention [Problem to be solved by the invention]

[0006] In the projector disclosed in Patent Document 1, the speckle noise is not sufficiently reduced by simply irradiating the composite light collected by the collecting lens onto a diffusion plate and emitting the diffused composite light from the diffusion plate, and further improvement is desired. In the light source device disclosed in Patent Document 2, the emission wavelength of the second laser element is shorter than the emission wavelength of the first laser element, so the light emitted from each laser element is unlikely to interfere with each other. Even if the light source device of Patent Document 2 is used, the wavelength difference between the light from the first laser element and the light from the second laser element is not large, so the speckle noise is not sufficiently reduced, and further improvement is desired. [Means for solving the problem]

[0007] The lighting device according to one embodiment of the present invention includes a first light source that emits a first light of a first color, a second light source that emits a second light of a different color from the first light, a light combining member that combines the first light and the second light to emit the combined light, a diffusion device having a substrate having a diffusion surface that diffuses and emits the combined light incident thereon, and a drive device that rotates the substrate, a light collecting element that is disposed between the light combining member and the diffusion device and collects the combined light on the diffusion surface of the diffusion device, and a collimating element that collimates the combined light emitted from the diffusion device. The first light source includes a plurality of first light-emitting elements that emit the first light in a first wavelength band, a plurality of second light-emitting elements that emit the first light in a second wavelength band different from the first wavelength band, a first heat dissipation member to which heat from the plurality of first light-emitting elements is transferred, and a second heat dissipation member to which heat from the plurality of second light-emitting elements is transferred. The heat dissipation capacity of the first heat dissipation member and the heat dissipation capacity of the second heat dissipation member are different from each other. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram showing the configuration of a projector according to a first embodiment. [Diagram 2] FIG. 2 is a schematic diagram of an illumination device of the projector of FIG. [Diagram 3] 3 is a schematic diagram of a substrate of a diffuser of the lighting device of FIG. 2. [Figure 4] FIG. 11 is a schematic diagram of an illumination device of a projector according to a second embodiment. [Diagram 5] FIG. 11 is a perspective view of an illumination device of a projector according to a third embodiment. [Figure 6] FIG. 6 is a plan view of the lighting device of FIG. 5. [Figure 7] FIG. 13 is a perspective view of a modified example of the illumination device of the projector according to the third embodiment. [Figure 8] FIG. 8 is a plan view of the lighting device of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In each drawing, the scale of the dimensions of some components may be changed in order to make each component easier to see.

[0010] (First embodiment) First, a projector 1 according to a first embodiment of the present invention will be described with reference to Fig. 1. Fig. 1 is a schematic diagram showing the configuration of the projector 1. The projector 1 is a projection type image display device that displays an image on a screen SCR. The projector 1 includes an illumination device 2, a color separation optical system 3, light modulation devices 4R, 4G, and 4B, a color synthesis optical system 5, and a projection optical system 6. The projector 1 is a three-plate type projector having three light modulation devices.

[0011] The illumination device 2 emits white light WL toward the color separation optical system 3. The white light WL is illumination light in the projector 1, and contains red light RL, green light GL, and blue light BL. The configuration of the illumination device 2 will be described later.

[0012] The color separation optical system 3 separates the white light WL into red light RL, green light GL, and blue light BL. The color separation optical system 3 includes, for example, a first dichroic mirror 11, a second dichroic mirror 12, a first total reflection mirror 13, a second total reflection mirror 14, a third total reflection mirror 15, a first relay lens 16, and a second relay lens 17.

[0013] The first dichroic mirror 11 is disposed on the optical path of the white light WL emitted from the lighting device 2, and separates the incident white light WL into red light RL, green light GL, and blue light BL. The first dichroic mirror 11 transmits the red light RL and reflects the green light GL and blue light BL. The second dichroic mirror 12 is disposed on the common optical path of the green light GL and blue light BL emitted from the first dichroic mirror 11, and separates the green light GL from the blue light BL. The second dichroic mirror 12 transmits the blue light BL and reflects the green light GL.

[0014] The first total reflection mirror 13 reflects the red light RL toward the light modulation device 4R. The second total reflection mirror 14 and the third total reflection mirror 15 guide the blue light BL to the light modulation device 4B. The green light GL is reflected from the second dichroic mirror 12 toward the light modulation device 4G. The red light RL, green light GL, and blue light BL contained in the white light WL correspond to the light emitted from the illumination device 2.

[0015] The first relay lens 16 is disposed on the optical path of the blue light BL between the second dichroic mirror 12 and the second total reflection mirror 14. The second relay lens 17 is disposed on the optical path of the blue light BL between the second total reflection mirror 14 and the third total reflection mirror 15. By disposing the first relay lens 16 and the second relay lens 17 as described above, the optical loss of the blue light BL is compensated. The optical loss of the blue light BL is caused by the optical path length of the blue light BL from the first dichroic mirror 11 to the optical modulation device 4B being longer than the optical path length of the red light RL from the first dichroic mirror 11 to the optical modulation device 4R and the optical path length of the green light GL from the first dichroic mirror 11 to the optical modulation device 4G.

[0016] The light modulation device 4R is disposed on the optical path of the red light RL reflected by the first total reflection mirror 13 and emitted from the first total reflection mirror 13. The light modulation device 4R modulates the incident red light RL according to image information input from an image input device (not shown), forms red image light, and emits the red image light. The light modulation device 4G is disposed on the optical path of the green light GL reflected by the second dichroic mirror 12 and emitted from the second dichroic mirror 12. The light modulation device 4G modulates the incident green light GL according to image information input from an image input device (not shown), forms green image light, and emits the green image light. The light modulation device 4B is disposed on the optical path of the blue light BL reflected by the third total reflection mirror 15 and emitted from the third total reflection mirror 15. The light modulation device 4B modulates the incident blue light BL according to image information input from an image input device (not shown), forms blue image light, and emits blue image light. The image input device may be, for example, a personal computer or a portable terminal device.

[0017] Each of the light modulation devices 4R, 4G, and 4B uses, for example, a transmissive liquid crystal panel. A polarizing plate (not shown) is disposed on each of the entrance side and exit side of the liquid crystal panel. A field lens 10R is disposed on the optical path of the red light RL between the first total reflection mirror 13 and the light modulation device 4R. A field lens 10G is disposed on the optical path of the green light GL between the second dichroic mirror 12 and the light modulation device 4G. A field lens 10B is disposed on the optical path of the blue light BL between the third total reflection mirror 15 and the light modulation device 4B.

[0018] The color synthesis optical system 5 is disposed across the optical path of the red image light emitted from the light modulation device 4R, the optical path of the green image light emitted from the light modulation device 4G, and the optical path of the blue image light emitted from the light modulation device 4B. When viewed from the top or side as shown in FIG. 1, the synthesis position of the color light in the color synthesis optical system 5 overlaps with the intersection of the optical path of the red image light, the optical path of the green image light, and the optical path of the blue image light. In the color synthesis optical system 5, the red image light, the green image light, and the blue image light are synthesized with each other to form color image light. The color synthesis optical system 5 emits color image light. For example, a cross dichroic prism is used for the color synthesis optical system 5.

[0019] The projection optical system 6 is disposed on the optical path of the color image light emitted from the color synthesis optical system 5. The color image light emitted from the color synthesis optical system 5 corresponds to the light modulated by the light modulation devices 4R, 4G, and 4B. The projection optical system 6 enlarges and projects the color image light emitted from and incident on the color synthesis optical system 5 toward the screen SCR. The color image light enlarged and projected from the projection optical system 6 is displayed as a color image on a display surface of the screen SCR facing the emission surface of the projection optical system 6.

[0020] The projection optical system 6 is composed of, for example, a plurality of optical lenses, but may be composed of a single optical lens. The optical lens includes various lenses, such as a plano-convex lens, a biconvex lens, a meniscus lens, an aspheric lens, a rod lens, and a free curved lens.

[0021] Next, the illumination device 2 according to the first embodiment of the present invention will be described with reference to Fig. 2 and Fig. 3. Fig. 2 is a schematic diagram showing the configuration of the illumination device 2. The illumination device 2 includes a first light source 20R, a second light source 20G, a third light source 20B, a light combining member 24, a condensing element 25, a diffusion device 40, a collimating element 26, and an integrated optical system 50.

[0022] The first light source 20R has a first laser element 21R1, a second laser element 21R2, a first heat dissipation member 211, a second heat dissipation member 212, and a first collimator lens 22R, and emits red light LR. The red light LR corresponds to the first light. The red light LR has a first wavelength band including at least wavelengths belonging to red in the visible wavelength band, and a second wavelength band including wavelengths belonging to red and longer than the first wavelength band. Red corresponds to the first color. The red light LR has a wavelength band of, for example, 585 nm to 720 nm.

[0023] The first laser element 21R1 corresponds to a first light emitting element. The first laser element 21R1 alone emits red light LR with a wavelength λR11 at an operating temperature T0. The operating temperature T0 is, for example, 25° C., which is within the range of room temperature and is a symbolic temperature when expressing the specifications and characteristics of a laser element. The wavelength λR11 is included in the first wavelength band of the red light LR.

[0024] The first heat dissipation member 211 receives heat from the first laser element 21R1. That is, the heat of the first laser element 21R1 is transferred to the first heat dissipation member 211. The first heat dissipation member 211 is, for example, a heat sink 121 made of a rectangular parallelepiped, and has two rectangular end faces parallel to each other and four side faces connecting each of the four sides of the two end faces. The heat sink 121 corresponds to the first heat sink. The two end faces of the heat sink 121 are, for example, parallel to an xy plane including an x ​​direction and a y direction perpendicular to the x direction. Two of the four side faces of the heat sink 121 are parallel to an xz plane including an x ​​direction and a z direction perpendicular to the x direction and the y direction. The other two of the four side faces of the heat sink 121 are parallel to a yz direction including the y direction and the z direction. For example, two first laser elements 21R1 are arranged at intervals from each other in the x direction, and two or more first laser elements 21R1 are arranged at intervals from each other in the y direction on an end face 121e on the z direction side of the two end faces of the heat sink 121. The end face 121e is the surface of the heat sink 121 that faces the light combining member 24.

[0025] The light emitting surface of the first laser element 21R1 is parallel to the xy plane and is the surface opposite to the surface of the first laser element 21R1 that contacts the end surface 121e of the heat sink 121. The first laser element 21R1 is heated by a voltage supplied from a power supply device (not shown) during light emission. At least a part of the heat of the first laser element 21R1 is dissipated by the adjacent heat sink 121. The first laser element 21R1 emits red light LR1 with a wavelength λR1 at an operating temperature T1 higher than the operating temperature T0. The wavelength λR1 is included in the first wavelength band of the red light LR and is longer than the wavelength λR11. That is, the wavelength of the red light LR1 emitted by the first laser element 21R1 increases from the wavelength λR11 to the wavelength λR1 as the operating temperature of the first laser element 21R1 increases.

[0026] The heat sink 121 has a heat dissipation capability to stabilize the temperature of the first laser elements 21R1 at the operating temperature T1 during light emission. The sizes of the heat sink 121 in the x, y, and z directions are set so that the heat sink 121 exhibits a heat dissipation capability to stabilize the temperature of the first laser elements 21R1 at the operating temperature T1 during light emission. The size of the heat sink 121 in the x direction is, for example, approximately half the size of the light combining member 24 in the x direction, which will be described later. The size of the heat sink 121 in the y direction is, for example, approximately the same as the size of the light combining member 24 in the y direction.

[0027] The first laser element 21R1 emits red light LR1 radially from the light receiving surface, centered in the z direction. As an example, the wavelength λR11 of the first laser element 21R1 at the operating temperature T0 is 638 nm, the operating temperature T1 is 45° C., and the wavelength λR1 at the operating temperature T1 is 640 nm.

[0028] The second laser element 21R2 corresponds to a second light emitting element. The second laser element 21R2 alone emits red light LR with a wavelength λR12 at an operating temperature T0. The wavelength λR12 is different from at least the wavelength λR11 and is included in a second wavelength band of the red light LR. The wavelength λR12 is, for example, longer than the wavelength λR11.

[0029] The second heat dissipation member 212 is disposed on the side opposite to the x-direction from the first heat dissipation member 211, and is disposed within a range overlapping with the first heat dissipation member 211 in the z-direction. The second heat dissipation member 212 receives heat from the second laser element 21R2. That is, the heat of the second laser element 21R2 is transferred to the second heat dissipation member 212.

[0030] The second heat dissipation member 212 is, for example, a heat sink 122 made of a rectangular parallelepiped, and has two parallel rectangular end faces and four side faces connecting the four sides of the two end faces. The heat sink 122 corresponds to a second heat sink. The two end faces of the heat sink 122 are, for example, parallel to the xy plane. Two of the four side faces of the heat sink 122 are parallel to the xz plane. The other two of the four side faces of the heat sink 122 are parallel to the yz direction. For example, two second laser elements 21R2 are arranged at intervals from each other in the x direction on the end face 122e on the z direction side of the two end faces of the heat sink 122, and two or more second laser elements 21R2 are arranged at intervals from each other in the y direction. The end face 122e is the surface of the heat sink 122 that faces the light combining member 24.

[0031] The light emitting surface of the second laser element 21R2 is parallel to the xy plane, and is the surface opposite to the surface of the second laser element 21R2 that is in contact with the end surface 122e of the heat sink 122. The second laser element 21R2 is heated by a voltage supplied from a power supply device (not shown) during light emission. At least a part of the heat of the second laser element 21R2 is dissipated by the adjacent heat sink 122. The second laser element 21R2 emits red light LR2 with a wavelength λR2 at an operating temperature T2 that is higher than the operating temperature T1. The wavelength λR2 is included in the second wavelength band of the red light LR and is longer than the wavelengths λR1 and λR12. That is, the wavelength of the red light LR2 emitted by the second laser element 21R2 increases from the wavelength λR12 to the wavelength λR2 as the operating temperature of the second laser element 21R2 increases.

[0032] The heat sink 122 has a heat dissipation capability to stabilize the temperature of the second laser elements 21R2 at the operating temperature T2 during light emission. The sizes of the heat sink 122 in the x-direction, y-direction, and z-direction are set so that the heat sink 122 exhibits the heat dissipation capability to stabilize the temperature of the second laser elements 21R2 at the operating temperature T2 during light emission.

[0033] The heat dissipation capacity of the heat sink 122, which is the second heat dissipation member 212, is different from the heat dissipation capacity of the heat sink 121, which is the first heat dissipation member 211. For example, since the operating temperature T2 is higher than the operating temperature T1, (T2-T0)>(T1-T0). In this case, the heat dissipation capacity of the heat sink 122, which is the second heat dissipation member 212, is smaller than the heat dissipation capacity of the heat sink 121, which is the first heat dissipation member 211. Specifically, the size of the heat sink 122 in the x direction and the y direction is equal to the size of the heat sink 121 in the x direction and the y direction. The size of the heat sink 122 in the z direction is smaller than the size of the heat sink 121 in the z direction.

[0034] The second laser element 21R2 emits red light LR2 radially from the light receiving surface with the z direction as the center. As an example, the wavelength λR12 of the second laser element 21R2 at the operating temperature T0 is 642 nm, the operating temperature T2 is 55° C., and the wavelength λR2 at the operating temperature T2 is 646 nm. As described above, when the wavelength λR11 of the first laser element 21R1 at the operating temperature T0 is 638 nm and the wavelength λR1 at the operating temperature T1 is 640 nm, the wavelength difference (λR12-λR11) between the oscillation peak wavelength of the first laser element 21R1 alone and the oscillation peak wavelength of the second laser element 21R2 alone at the operating temperature T0 is 4 nm. A heat sink 121 is connected to the first laser element 21R1, and a heat sink 122 is connected to the second laser element 21R2. Therefore, the wavelength difference (λR2-λR1) between the red light LR1 of the first wavelength band emitted from the first laser element 21R1 at the operating temperature T1 and the red light LR2 of the second wavelength band emitted from the second laser element 21R2 at the operating temperature T2 is 6 nm, which is larger than the wavelength difference (λR12-λR11).

[0035] That is, as the operation of the illumination device 2 continues, the temperatures of the first laser element 21R1 and the second laser element 21R2 rise, and the first light source 20R changes from a state in which it emits red light LR of two types of wavelengths λR11 and λR12, the difference in wavelength being 4 nm, at the operating temperature T0 to a state in which it emits red light LR of two types of wavelengths λR1 and λR2, the difference in wavelength being 6 nm. That is, the difference between the two types of wavelengths increases.

[0036] The number of the first collimating lenses 22R is the same as the total number of the first laser elements 21R1 and the second laser elements 21R2. The first collimating lenses 22R are disposed on the optical path of the red light LR1 emitted from each of the first laser elements 21R1, and are disposed on the optical path of the red light LR2 emitted from each of the second laser elements 21R2. The center of the first collimating lens 22R in the x direction substantially overlaps with the center of the light emitting surface of the first laser element 21R1 corresponding to the first collimating lens 22R, or the center of the light emitting surface of the second laser element 21R2.

[0037] The first collimator lens 22R collimates the incident red light beams LR1 and LR2. The red light beams LR1 and LR2 collimated by the first collimator lens 22R travel along the z direction. The optical axis AX1 of the red light beam LR emitted from the first light source 20R is parallel to the z direction.

[0038] The second light source 20G is disposed on the z-direction side of the first light source 20R and on the opposite side of the x-direction from the first light source 20R. The second light source 20G has a first laser element 21G1, a second laser element 21G2, a first heat dissipation member 221, a second heat dissipation member 222, and a second collimator lens 22G, and emits green light LG. The green light LG corresponds to the second light. The green light LG has a first wavelength band including at least wavelengths belonging to green in the visible wavelength band, and a second wavelength band including wavelengths belonging to green and longer than the first wavelength band. The green color corresponds to the second color and is a color different from red, which is the first color. The green light LG has a wavelength band of, for example, 495 nm to 585 nm.

[0039] The first laser element 21G1 alone emits green light LG with a wavelength λG11 at an operating temperature T0. The wavelength λG11 is included in a first wavelength band of the green light LG.

[0040] The first heat dissipation member 221 receives heat from the first laser element 21G1. That is, the heat of the first laser element 21G1 is transferred to the first heat dissipation member 221. The first heat dissipation member 221 is, for example, a heat sink 131 made of a rectangular parallelepiped, and has two rectangular end faces parallel to each other and four side faces connecting each of the four sides of the two end faces. The two end faces of the heat sink 131 are, for example, parallel to the yz plane. Two of the four side faces of the heat sink 131 are parallel to the xy plane. The other two of the four side faces of the heat sink 131 are parallel to the xz direction. For example, two first laser elements 21G1 are arranged at intervals from each other in the z direction on the end face 131e on the x direction side of the two end faces of the heat sink 131, and two or more first laser elements 21G1 are arranged at intervals from each other in the y direction. The end surface on which the two first laser elements 21G1 are provided is the surface of the heat sink 131 that faces the light combining member 24.

[0041] The light emitting surface of the first laser element 21G1 is parallel to the yz plane. The first laser element 21G1 is heated by a voltage supplied from a power supply device (not shown) during light emission. At least a part of the heat of the first laser element 21G1 is dissipated by the adjacent heat sink 131. The first laser element 21G1 emits green light LG1 with a wavelength λG1 at an operating temperature T11 higher than the operating temperature T0. The wavelength λG1 is included in the first wavelength band of the green light LG and is longer than the wavelength λG11. That is, the wavelength of the green light LG1 emitted by the first laser element 21G1 increases from the wavelength λG11 to the wavelength λG1 as the operating temperature of the first laser element 21G1 increases.

[0042] The heat sink 131 has a heat dissipation capability to stabilize the temperature of the first laser element 21G1 at the operating temperature T11 during light emission. The sizes of the heat sink 131 in the x, y, and z directions are set so that the heat sink 131 exhibits a heat dissipation capability to stabilize the temperature of the first laser elements 21G1 at the operating temperature T11 during light emission. The size of the heat sink 131 in the z direction is, for example, about half the size of the light combining member 24 in the z direction. The size of the heat sink 131 in the y direction is, for example, equal to the size of the light combining member 24 in the y direction.

[0043] The first laser element 21G1 emits green light LG1 radially from the x direction as the center.

[0044] The second laser element 21G2 alone emits green light LG with a wavelength λG12 at an operating temperature T0. The wavelength λG12 is different from at least the wavelength λG11 and is included in a second wavelength band of the green light LG. The wavelength λG12 is, for example, longer than the wavelength λG11.

[0045] The second heat dissipation member 222 is disposed on the z-direction side of the first heat dissipation member 221, and is disposed in a range overlapping with the first heat dissipation member 221 in the x-direction. The second heat dissipation member 222 receives heat from the second laser element 21G2. That is, the heat of the second laser element 21G2 is transferred to the second heat dissipation member 222.

[0046] The second heat dissipation member 222 is, for example, a heat sink 132 made of a rectangular parallelepiped, and has two rectangular end faces parallel to each other and four side faces connecting the four sides of the two end faces. The two end faces of the heat sink 132 are, for example, parallel to the yz plane. Two of the four side faces of the heat sink 132 are parallel to the xy plane. The other two of the four side faces of the heat sink 132 are parallel to the xz direction. For example, two second laser elements 21G2 are arranged at intervals from each other in the z direction on the end face 132e on the x direction side of the two end faces of the heat sink 132, and two or more second laser elements 21G2 are arranged at intervals from each other in the y direction. The end face on which the two second laser elements 21G2 are provided is the face of the heat sink 132 facing the light combining member 24.

[0047] The light emitting surface of the second laser element 21G2 is parallel to the yz plane. The second laser element 21G2 is heated by a voltage supplied from a power supply device (not shown) during light emission. At least a part of the heat of the second laser element 21G2 is dissipated by the adjacent heat sink 132. The second laser element 21G2 emits green light LG2 with a wavelength λG2 at an operating temperature T12 higher than the operating temperature T11. The wavelength λG2 is included in the second wavelength band of the green light LG and is longer than the wavelengths λG1 and λG12. That is, the wavelength of the green light LG2 emitted by the second laser element 21G2 increases from the wavelength λG12 to the wavelength λG2 as the operating temperature of the second laser element 21G2 increases. The heat sink 132 has a heat dissipation ability to stabilize the temperature of the second laser element 21G2 during light emission at the operating temperature T12. The sizes of the heat sink 132 in the x-direction, y-direction, and z-direction are set so that the heat sink 132 exhibits the heat dissipation capability to stabilize the temperature of the multiple second laser elements 21G2 at the operating temperature T12 during light emission.

[0048] The heat dissipation capacity of the heat sink 132, which is the second heat dissipation member 222, is different from the heat dissipation capacity of the heat sink 131, which is the first heat dissipation member 221. For example, since the operating temperature T12 is higher than the operating temperature T11, (T12-T0)>(T11-T0). In this case, the heat dissipation capacity of the heat sink 132, which is the second heat dissipation member 222, is smaller than the heat dissipation capacity of the heat sink 131, which is the first heat dissipation member 221. Specifically, the size of the heat sink 132 in the y direction and the z direction is equal to the size of the heat sink 131 in the y direction and the z direction. The size of the heat sink 132 in the x direction is smaller than the size of the heat sink 131 in the x direction.

[0049] The second laser element 21G2 emits green light LG2 radially from the light receiving surface centered in the x direction. A heat sink 131 is connected to the first laser element 21G1, and a heat sink 132 is connected to the second laser element 21G2. Therefore, the wavelength difference (λG2-λG1) between the green light LG1 of the first wavelength band emitted from the first laser element 21G1 at the operating temperature T11 and the green light LG2 of the second wavelength band emitted from the second laser element 21G2 at the operating temperature T12 is larger than the wavelength difference (λG12-λG11) between the oscillation peak wavelength of the first laser element 21G1 alone and the oscillation peak wavelength of the second laser element 21G2 alone at the operating temperature T0.

[0050] That is, as the operation of the illumination device 2 continues, the temperatures of the first laser element 21G1 and the second laser element 21G2 rise, and the second light source 20G also changes from a state in which it emits green light LG of two wavelengths λG11 and λG12 at the operating temperature T0 to a state in which it emits green light LG of two wavelengths λG1 and λG2. That is, the difference between the two wavelengths increases.

[0051] The number of the second collimator lenses 22G is the same as the total number of the first laser elements 21G1 and the second laser elements 21G2. The second collimator lenses 22G are disposed on the optical path of the green light LG1 emitted from each of the first laser elements 21G1, and are disposed on the optical path of the green light LG2 emitted from each of the second laser elements 21G2. The center of the second collimator lens 22G in the z direction is substantially overlapped with the center of the light emitting surface of the first laser element 21G1 corresponding to the second collimator lens 22G, or the center of the light emitting surface of the second laser element 21G2.

[0052] The second collimator lens 22G collimates the incident green light beams LG1 and LG2. The green light beams LG1 and LG2 collimated by the second collimator lens 22G travel along the x direction. The optical axis AX2 of the green light beam LG emitted from the second light source 20G is parallel to the x direction.

[0053] The third light source 20B is disposed on the z-direction side of the second light source 20G, and is disposed within a range overlapping with the first light source 20R in the x-direction. The third light source 20B has a laser element 21B and a collimator lens 22B, and emits blue light LB. The blue light LB has a wavelength band that includes at least wavelengths belonging to blue in the visible wavelength band. Blue is a color different from red, which is the first color, and green, which is the second color. The blue light LB has a wavelength band of, for example, 380 nm to 495 nm.

[0054] The third light source 20B has, for example, four laser elements 21B. The four laser elements 21B are arranged at intervals in the x direction. The light emitting surface of each laser element 21B is parallel to the xy plane. The laser element 21B emits blue light LB radially from the z direction and in the opposite direction to the z direction.

[0055] The number of collimator lenses 22B is the same as the total number of laser elements 21B. The collimator lenses 22B are disposed on the optical path of the blue light LB emitted from each laser element 21B. The center of the collimator lens 22B in the x direction substantially overlaps with the center of the light emitting surface of the laser element 21B corresponding to the collimator lens 22B.

[0056] The collimator lens 22B collimates the incident blue light LB. The blue light LB collimated by the collimator lens 22B travels in the direction opposite to the z direction. The optical axis AX1 of the blue light LB emitted from the third light source 20B is parallel to the z direction.

[0057] The optical axis AX1 of the blue light LB is collinear with the optical axis AX1 of the red light LR, and is an axis that extends from the optical axis AX1 of the red light LR toward the light combining member 24, passing through the combination position of the colored lights in the light combining member 24, and further in the opposite direction from the first light source 20R relative to the light combining member 24.

[0058] Each of the first light source 20R, the second light source 20G, and the third light source 20B may have components other than the various laser light sources, the collimator lens, and the various heat dissipation components, such as a package that holds the various laser light sources and the collimator lens.

[0059] The light combining member 24 is disposed across the optical path of the red light LR emitted from the first light source 20R, the optical path of the green light LG emitted from the second light source 20G, and the optical path of the blue light LB emitted from the third light source 20B. When viewed from the top or side as shown in Fig. 2, the combining position of the colored lights in the light combining member 24 overlaps with the intersection of the optical path of the red light LR, the optical path of the green light LG, and the optical path of the blue light LB, i.e., the intersection of the optical axis AX1 and the optical axis AX2.

[0060] In the light combining member 24, the incident red light LR, green light LG, and blue light LB are combined together to generate white light WL. The white light WL corresponds to the combined light. The light combining member 24 emits the white light WL along the optical axis AX2. The optical axis AX2 of the white light WL is collinear with the optical axis AX2 of the green light LG. The optical axis AX2 of the white light WL is an axis that extends the optical axis AX2 of the green light LG toward the light combining member 24 so as to pass through the combination position of the colored lights in the light combining member 24, and is further extended in the opposite direction to the second light source 20G with respect to the light combining member 24.

[0061] For example, a cross dichroic prism 240 is used for the light combining member 24. The cross dichroic prism 240 has a first dichroic mirror 241 and a second dichroic mirror 242. In a plan view or a side view in which the optical axes AX1 and AX2 are perpendicular to each other, the reflecting surface of the first dichroic mirror 241 and the reflecting surface of the second dichroic mirror 242 are inclined with respect to the optical axes AX1 and AX2. In a plan view or a side view, the angle formed by each of the reflecting surfaces of the first dichroic mirror 241 and the second dichroic mirror 242 and each of the optical axes AX1 and AX2 is 45°. In a plan view or a side view in which the optical axes AX1 and AX2 are perpendicular to each other, the reflecting surface of the first dichroic mirror 241 and the reflecting surface of the second dichroic mirror 242 are perpendicular to each other.

[0062] The first dichroic mirror 241 reflects the blue light LB and transmits the green light LG and the red light LR. The second dichroic mirror 242 reflects the red light LR and transmits the blue light LB and the green light LG. The red light LR emitted from the first light source 20R enters the second dichroic mirror 242 along the optical axis AX1, is reflected by the second dichroic mirror 242, and is emitted along the optical axis AX2 to the opposite side to the second light source 20G and transmits through the first dichroic mirror 241. The green light LG emitted from the second light source 20G enters the first dichroic mirror 241 along the optical axis AX2, travels straight, and transmits through the first dichroic mirror 241 and the second dichroic mirror 242. The blue light LB emitted from the third light source 20B enters the first dichroic mirror 241 along the optical axis AX1, is reflected by the first dichroic mirror 241, and is emitted opposite the second light source 20G along the optical axis AX2, and passes through the second dichroic mirror 242.

[0063] As described above, the red light RL, the green light LG, and the blue light LB emitted from the first dichroic mirror 241 and the second dichroic mirror 242 are combined with each other to generate the white light WL. The white light WL is emitted along the optical axis AX2 from the side surface of the cross dichroic prism 240 opposite to the side surface facing the second light source 20G.

[0064] The light collecting element 25 is disposed on the optical path of the white light WL between the light combining member 24 and the diffusing device 40. The light collecting element 25 collects the white light WL emitted from the light combining member 24 and in a collimated state toward the diffusing device 40. The center of the light collecting element 25 in a direction perpendicular to the optical axis AX2 substantially overlaps with the optical axis AX2. The light collecting element 25 is, for example, a biconvex lens, but may be an optical element having a light collecting function other than a biconvex lens, may be a plano-convex lens, or may be composed of a plurality of optical lenses.

[0065] The diffusion device 40 is disposed on the optical path of the white light WL emitted from the focusing element 25. The diffusion device 40 diffuses and emits the incident white light WL while being focused by the focusing element 25. The diffusion device 40 is, for example, a reflective diffusion device, and diffuses and reflects the incident white light WL.

[0066] The diffusion device 40 has, for example, a substrate 41 and a driving device 42. The substrate 41 has an incident surface 41a onto which the white light WL collected by the light collecting element 25 is irradiated to form a focused spot SP of the white light WL, and a back surface 41b on the opposite side to the incident surface 41a. The substrate 41 is disposed such that the incident surface 41a faces the light collecting element 25. In a plan view or side view in which the optical axes AX1 and AX2 are perpendicular to each other, the angle between the incident surface 41a and the optical axis AX2 is 45°.

[0067] The substrate 41 is mounted on the driving device 42 in a state in which it can rotate around the rotation axis OX1. The driving device 42 rotates the substrate 41 around the rotation axis OX1. The driving device 42 is, for example, a motor, and has an axis member 43 with the rotation axis OX1 as its axis. The axis member 43 is, for example, inserted into the center of the substrate 41 from the back surface 41b side. The centers of the incident surface 41a and the back surface 41b of the substrate 41 overlap with the rotation axis OX1. The substrate 41 rotates around the rotation axis OX1 as described above in conjunction with the rotation of the axis member 43 around the rotation axis OX1, and diffuses the white light WL. Note that the driving device 42 may be any device that can rotate the substrate 41 as described above, and is not limited to a motor.

[0068] FIG. 3 is a schematic diagram of the substrate 41 of the diffusion device 40, and is a view of the substrate 41 viewed from the incident surface 41a side along the rotation axis OX1. As shown in FIG. 2 and FIG. 3, when viewed along the rotation axis OX1, the focused spot SP of the white light WL is formed in the region between the center, i.e., the rotation axis OX1 and the peripheral end in the radial direction centered on the incident surface 41a of the substrate 41. The incident surface 41a constitutes a diffusion surface 45 that diffuses and emits the incident white light WL. The incident surface 41a has an uneven structure 47 formed thereon. The uneven structure 47 is appropriately designed in consideration of the wavelength band of the white light WL so as to appropriately diffuse the white light WL, and is created in the same manner as the uneven structure formed on a known diffusion plate. The uneven structure 47 may be formed, for example, by blasting, or may be realized by forming a plurality of microlenses having a diameter equal to or smaller than the wavelength of the white light WL using a photolithography technique. The uneven structure 47 may be formed, for example, by scattering a plurality of particles having an appropriate particle size on the base material of the substrate 41 and covering the plurality of particles with a resin so as to reflect the surface shape of the plurality of particles. Note that the uneven structure 47 may be formed over the entire radial range from the center to the peripheral edge of the incident surface 41a as shown in Fig. 3, but it is sufficient that the uneven structure 47 is formed over at least a portion of the radial range including the region irradiated with the focused spot SP.

[0069] When the substrate 41 is made of a material that is transparent to the white light WL, such as optical glass or plastic, a reflective film (not shown) is provided on the surface of the uneven structure 47. When the substrate 41 is made of a material that is reflective to the white light WL, such as a metal, a reflective film (not shown) does not need to be provided on the surface of the uneven structure 47, but providing a reflective film improves the reflection characteristics of the incident surface 41a. Note that the uneven structure 47 is illustrated by dots in FIG. 3. The uneven structure 47 is made of a material that is transparent to the white light WL and does not have light blocking properties, like the substrate 41.

[0070] The white light WL is diffused and reflected by the diffusion surface 45. In the diffused white light WL, the red light LR1 in the first wavelength band and the red light LR2 in the second wavelength band of the red light LR contained in the white light WL, the green light LG1 in the first wavelength band and the green light LG2 in the second wavelength band of the green light LG contained in the white light WL, and the blue light LB contained in the white light WL are mixed together. The red light LR1, LR2, the green light LG1, LG2, and the blue light LB are distributed approximately uniformly in a plane intersecting the optical axes AX2, AX10 of the light-focused spot SP of the white light WL. The speckle pattern of the white light WL in the light-focused spot SP changes as the substrate 41 of the diffusion device 40 rotates in the rotation direction DR about the rotation axis OX1.

[0071] The white light WL is diffused and reflected by the diffusion surface 45, contains a diffusion, scattering or diffraction pattern due to the uneven structure 47, and is emitted as diffuse light from the focused spot SP along the optical axis AX10. The optical axis AX10 passes through the center of the irradiation area of ​​the focused spot SP on the incident surface 41a of the substrate 41, and is parallel to the optical axis AX1.

[0072] The collimating element 26 is disposed on the optical path of the white light WL emitted from the substrate 41 of the diffusion device 40. The collimating element 26 collimates the white light WL emitted from the incident surface 41a and the diffusion surface 45 of the substrate 41 and in a divergent and diffused state. The center of the collimating element 26 in a direction perpendicular to the optical axis AX10 is approximately overlapped with the optical axis AX10. The collimating element 26 is, for example, a biconvex lens, but may be an optical element having a light-collecting function other than a biconvex lens, may be a plano-convex lens, or may be composed of multiple optical lenses. When the collimating element 26 is composed of one optical lens, the accuracy of collimation can be further improved by using an aspheric lens.

[0073] The integrating optical system 50 has a multi-lens array 51 and a superimposing lens 52. The integrating optical system 50 homogenizes the illuminance distribution of the white light WL emitted from the collimating element 26 in the image forming areas of the optical modulation devices 4R, 4G, and 4B arranged downstream.

[0074] The multilens array 51 is disposed on the optical path of the white light WL emitted from the collimating element 26 and collimated. The multilens array 51 is, for example, a double-sided multilens array. The double-sided multilens includes a plurality of microlenses 53 for splitting the white light WL emitted from the collimating element 26 into a plurality of small beams. The plurality of microlenses 53 are disposed adjacent to each other in a matrix along a plane perpendicular to the optical axis AX10. The microlenses 53 are, for example, plano-convex lenses that are convex toward the incident side. The double-sided multilens has a first multilens surface 51a that is provided on the incident side along the shape of the plano-convex lens that constitutes the microlens 53. The double-sided multilens includes a plurality of microlenses 54, the same number as the plurality of microlenses 53, on a surface perpendicular to the optical axis AX10. The respective microlenses 54 are disposed adjacent to each other in a matrix along a plane perpendicular to the optical axis AX10, and overlap with each of the microlenses 53. The microlenses 54 are, for example, plano-convex lenses that are convex toward the exit side. The exit-side plane of each of the multiple microlenses 54 is common to the entrance-side plane of each of the multiple microlenses 53. The double-sided multi-lens has a second multi-lens surface 51b provided on the exit side along the shape of the plano-convex lens that constitutes the microlens 54.

[0075] The superimposing lens 52 collects each of the multiple small beams of the white light WL emitted from the multilens array 51, and superimposes the collected beams on each other in the image forming area or in the vicinity of the image forming area of ​​each of the light modulation devices 4R, 4G, and 4B in cooperation with the multiple microlenses 54 of the multilens array 51. The superimposing lens 52 is, for example, a plano-convex lens, but may be an optical element having a light collecting function other than a plano-convex lens, may be a biconvex lens, or may be composed of multiple optical lenses.

[0076] The illumination device 2 of the first embodiment described above includes the first light source 20R, the second light source 20G, the light combining member 24, the diffusion device 40, the light collecting element 25, and the collimating element 26. The first light source 20R emits red light (first light of a first color) LR. The second light source 20G emits blue light (second light having a different color from the first light) LB. The light combining member 24 combines the red light LR and the green light GL to emit white light (combined light) WL. The diffusion device 40 includes a substrate 41 having a diffusion surface 45 that diffuses and emits the incident white light WL, and a driving device 42 that rotates the substrate 41. The light collecting element 25 is disposed between the light combining member 24 and the diffusion device 40, and collects the white light WL on the diffusion surface 45 of the substrate 41 of the diffusion device 40. The collimating element 26 collimates the white light WL emitted from the substrate 41 of the diffusion device 40. The first light source 20R has a plurality of first laser elements (first light-emitting elements) 21R1, a plurality of second laser elements (second light-emitting elements) 21R2, a first heat dissipation member 211, and a second heat dissipation member 212. Heat from the plurality of first laser elements 21R1 is transferred to the first heat dissipation member 211. Heat from the plurality of second laser elements 21R2 is transferred to the second heat dissipation member 212. The first laser element 21R1 emits red light LR1 in a first wavelength band. The second laser element 21R2 emits red light LR2 in a second wavelength band different from the first wavelength band. The heat dissipation capacity of the first heat dissipation member 211 and the heat dissipation capacity of the second heat dissipation member 212 are different from each other.

[0077] In contrast to the illumination device 2 of the first embodiment, a conventional illumination device has a configuration in which the first light source 20R includes only the first laser element 21R1. In the illumination device 2 of the first embodiment, the first light source 20R includes the second laser element 21R2 that emits red light LR2 in addition to the first laser element 21R1 that emits red light LR1. In the illumination device 2 of the first embodiment, compared to a conventional illumination device not including the second laser element 21R2, a wavelength difference (λR12-λR11) occurs in the red light LR included in the white light WL diffused by the diffusion device 40 and incident on the integrated optical system 50, and the speckle noise caused by the white light WL is reduced. According to the illumination device 2 of the first embodiment, when the white light WL emitted from the illumination device 2 is projected, the speckle noise generated in the projected image can be effectively reduced.

[0078] Examples of conventional lighting devices different from the above-mentioned conventional lighting devices include a configuration in which the first light source 20R has the first laser element 21R1 and the second laser element 21R2, and does not include the first heat dissipation member 211 and the second heat dissipation member 212, and a configuration in which the heat dissipation capacity of the first heat dissipation member 211 and the heat dissipation capacity of the second heat dissipation member 212 are the same. In the lighting device 2 of the first embodiment, the first laser element 21R1 emits red light LR1 at an operating temperature T1 higher than a reference operating temperature T0 due to heat dissipation of the first heat dissipation member 211, and the second laser element 21R2 emits red light LR2 at an operating temperature T2 different from the operating temperatures T0 and T1 due to heat dissipation of the second heat dissipation member 212. Therefore, in the lighting device 2 of the first embodiment, by appropriately setting the heat dissipation capabilities of each of the first heat dissipation member 211 and the second heat dissipation member 212, the wavelength difference (λR2-λR1) in the red light LR contained in the white light WL diffused by the diffusion device 40 and incident on the integrated optical system 50 becomes larger than the wavelength difference (λR12-λR11) compared to a conventional lighting device not including the first heat dissipation member 211 and the second heat dissipation member 212 and a configuration in which the heat dissipation capabilities of the heat dissipation members are equivalent to each other, and the speckle noise caused by the white light WL is favorably reduced. According to the lighting device 2 of the first embodiment, when the white light WL emitted from the lighting device 2 is projected, the speckle noise generated in the projected image can be favorably and effectively reduced.

[0079] In a conventional lighting device not including the first heat dissipation member 211 and the second heat dissipation member 212, and in a configuration in which the heat dissipation capabilities of the heat dissipation members are equal to each other, a countermeasure to enlarge the wavelength difference (λR12-λR11) is to prepare a first laser element 21R1 that emits red light LR1 having a red wavelength equivalent to the wavelength λR1 alone at the operating temperature T0, and a second laser element 21R2 that emits red light LR2 having a red wavelength equivalent to the wavelength λR2 alone at the operating temperature T0. However, this countermeasure requires manufacturing many types of the first laser element 21R1 and the second laser element 21R2 in order to realize a desired wavelength difference (λR2-λR1) in the red light LR, which results in a huge manufacturing process, workload, and cost compared to a case in which the heat dissipation capabilities of the first heat dissipation member 211 and the second heat dissipation member 212 are adjusted. According to the illumination device 2 of the first embodiment, it is possible to easily and at low cost reduce speckle noise occurring in the white light WL emitted from the illumination device 2 and in the projected image. In addition, since it is not necessary to use the second laser element 21R2 that emits red light LR2 with an excessively long wavelength, early performance degradation of the second laser element 21R2 in the illumination device 2 can be prevented.

[0080] In the lighting device 2 of the first embodiment, the first wavelength band is shorter than the second wavelength band. The heat dissipation capacity of the first heat dissipation member 211 is greater than the heat dissipation capacity of the second heat dissipation member 212.

[0081] In the illumination device 2 of the first embodiment, the first laser element 21R1 emits red light LR1 at an operating temperature T1 due to heat dissipation from the first heat dissipation member 211, and the second laser element 21R2 emits red light LR2 at an operating temperature T2 higher than the operating temperature T1 due to heat dissipation from the second heat dissipation member 212. As a result, the wavelength difference (λR2-λR1) in the red light LR contained in the white light WL incident on the integrated optical system 50 becomes larger than the wavelength difference (λR12-λR11), and the speckle noise caused by the white light WL is reduced satisfactorily. According to the illumination device 2 of the first embodiment, when the white light WL emitted from the illumination device 2 is projected, the speckle noise generated in the projected image can be reduced satisfactorily and effectively.

[0082] In the lighting device 2 of the first embodiment, the first heat dissipation member 211 may include a heat sink (first heat sink) 121 having a plurality of first fins. The second heat dissipation member 212 may include a heat sink (second heat sink) 122 having a plurality of second fins. In the lighting device 2 of the first embodiment, the size of the heat sink 121 is larger than the size of the heat sink 122.

[0083] Although omitted in FIG. 2, in the lighting device 2 of the first embodiment, a plurality of first fins may be provided on an end face or side face other than the end face 121e of the heat sink 121 constituting the first heat dissipation member 211. The size and number of the first fins are set so that the heat sink 121 exhibits a heat dissipation ability to stabilize the temperature of the first laser element 21R1 at the operating temperature T1 when the heat sink 121 is emitting light by providing a plurality of first fins. Similarly, a plurality of second fins may be provided on an end face or side face other than the end face 122e of the heat sink 122 constituting the second heat dissipation member 212. The size and number of the second fins are set so that the heat sink 122 exhibits a heat dissipation ability to stabilize the temperature of the second laser element 21R2 at the operating temperature T2 when the heat sink 122 is emitting light by providing a plurality of second fins. In this configuration, the heat dissipation ability of the heat sink 121 is greater than that of the heat sink 122. According to the illumination device 2 of the first embodiment, the wavelength difference (λR2-λR1) in the red light LR contained in the white light WL incident on the integrated optical system 50 is made larger than the wavelength difference (λR12-λR11), thereby effectively reducing the speckle noise caused by the white light WL.

[0084] In the lighting device 2 of the first embodiment, the number of the plurality of first fins may be greater than the number of the plurality of second fins. In this configuration, similar to the case where the size of the heat sink 121 is greater than the size of the heat sink 122, the heat dissipation capacity of the heat sink 121 is greater than the heat dissipation capacity of the heat sink 122. Therefore, according to the lighting device 2 of the first embodiment, the wavelength difference (λR2-λR1) in the red light LR contained in the white light WL incident on the integrated optical system 50 is made greater than the wavelength difference (λR12-λR11), and speckle noise due to the white light WL can be effectively reduced.

[0085] Although omitted in Fig. 2, the first heat dissipation member 211 may include a heat sink 121 having a plurality of first fins and a third heat sink having a plurality of third fins. The second heat dissipation member 212 may include a heat sink 122 having a plurality of second fins. The heat sink 121 and the third heat sink may be connected by a heat transport member. An example of the heat transport member is a heat pipe.

[0086] In the lighting device 2 of the first embodiment, the third heat sink is thermally connected to the heat sink 121 by the heat transport member, and thus the operating temperature T1 can be easily adjusted by the heat dissipation capacity of the third heat sink, compared to the case where only the heat sink 121 is connected to the first laser element 21R1. Note that the number of heat sinks or heat dissipation members other than heat sinks connected to at least one of the heat sink 121 constituting the first heat dissipation member 211 or the heat sink 122 constituting the second heat dissipation member 212 is not particularly limited, and is appropriately set according to the desired operating temperature T1.

[0087] The number of the first laser elements 21R1 and the number of the second laser elements 21R2 included in the first light source 20R are not limited to two, and are appropriately set in consideration of the light amount of the red light LR, the light emission amount of the first laser element 21R1, and the light emission amount of the second laser element 21R2 required for the lighting device 2. Similarly, the number of the first laser elements 21G1 and the number of the second laser elements 21G2 included in the second light source 20G are not limited to two, and are appropriately set in consideration of the light amount of the green light LG, the light emission amount of the first laser element 21G1, and the light emission amount of the second laser element 21G2 required for the lighting device 2. The number of the laser elements 21B included in the third light source 20B is not limited to four, and is appropriately set in consideration of the light amount of the blue light LB and the light emission amount of the laser element 21B required for the lighting device 2.

[0088] In addition, in the x direction, the two first laser elements 21R1 and the heat sink 121, and the two second laser elements 21R2 and the heat sink 122 may be arranged in a mutually interchangeable manner.

[0089] In the lighting device 2 of the first embodiment, the first light is red.

[0090] Of the three primary colors contained in the white light WL, speckle noise caused by red light LR is easily noticeable. According to the illumination device 2 of the first embodiment, the wavelength difference (λR2-λR1) in the red light LR contained in the white light WL incident on the integrated optical system 50 is made larger than the wavelength difference (λR12-λR11), and the speckle noise caused by the red light LR contained in the white light WL can be effectively reduced.

[0091] As described above, in the lighting device 2 of the first embodiment, for example, two first laser elements 21R1 are arranged at intervals from each other in the x direction on the end face on the z direction side of the two end faces of the heat sink 121, and two or more first laser elements 21R1 are arranged at intervals from each other in the y direction. Note that, in the lighting device 2 of the first embodiment, the number of the multiple first laser elements 21R1 in the x direction and the y direction on the end face 121e of the heat sink 121 may be changed and appropriately set. Similarly, the number of the multiple second laser elements 21R2 in the x direction and the y direction on the end face 122e of the heat sink 122 may be changed and appropriately set. In the lighting device 2 of the first embodiment, the number of the multiple first laser elements 21G1 in the z direction and the y direction on the end face 131e of the heat sink 131 may be changed and appropriately set. Similarly, the number of the multiple second laser elements 21G2 in the z direction and the number of the multiple second laser elements 21G2 in the y direction on the end surface 132e of the heat sink 132 may be changed and is set appropriately.

[0092] In the illumination device 2 of the first embodiment, the blue light LB of the three primary colors included in the white light WL is sufficiently diffused by the diffusion device 40, and speckle noise caused by the blue light LB is unlikely to be apparent. Therefore, the third light source 20B does not include a heat dissipation member. On the other hand, speckle noise caused by the red light LR and the green light LG of the three primary colors included in the white light WL is likely to be apparent. Therefore, the first light source 20R and the second light source 20G include heat dissipation members connected to each laser element as described above. However, if the speckle noise caused by the green light LG is not apparent even if the first heat dissipation member 221 and the second heat dissipation member 222 are not connected to the first laser element 21G1 and the second laser element 21G2, the first heat dissipation member 221 and the second heat dissipation member 222 may be omitted in the second light source 20G.

[0093] The projector 1 of the first embodiment includes the above-mentioned illumination device 2, light modulation devices 4R, 4G, and 4B, and a projection optical system 6. The light modulation device 4R modulates red light RL contained in white light WL emitted from the illumination device 2 to generate red image light. The light modulation device 4G modulates green light GL contained in the white light WL to generate green image light. The light modulation device 4B modulates blue light BL contained in the white light WL to generate blue image light. The projection optical system 6 projects the image light modulated by the light modulation devices 4R, 4G, and 4B.

[0094] In the projector 1 of the first embodiment, the diffusion, scattering or diffraction pattern and the speckle pattern in the white light WL emitted from the illumination device 2 change effectively over time, thereby reducing speckle noise. According to the projector 1 of the first embodiment, when the white light WL emitted from the illumination device 2 is converted into image light by the light modulation devices 4R, 4G, and 4B and the image light is projected onto the screen SCR, speckle noise occurring in the projected image can be effectively reduced.

[0095] Second embodiment Next, a lighting device 102 according to a second embodiment of the present invention will be described with reference to Fig. 4. In the description of the second embodiment, the contents common to the first embodiment are omitted, and only the configuration and contents different from the configuration already described in the first embodiment are described.

[0096] Although not shown, the projector of the second embodiment includes an illumination device 102, which will be described next, instead of the illumination device 2 in the projector 1 of the first embodiment.

[0097] 4 is a schematic diagram showing the configuration of the illumination device 102. The illumination device 102 includes a first light source 20R, a second light source 20G, a third light source 20B, a light combining member 24, a condensing element 25, a diffusing device 40, a collimating element 26, and an integrated optical system 50.

[0098] The first light source 20R has a plurality of first laser elements 21R1, a plurality of second laser elements 21R2, a plurality of third laser elements 21R3, a plurality of fourth laser elements 21R4, a first heat dissipation member 211, a second heat dissipation member 212, a third heat dissipation member 213, a fourth heat dissipation member 214, and a first collimator lens 22R, and emits red light LR. The third laser element 21R3 corresponds to a third light emitting element. The fourth laser element 21R4 corresponds to a fourth light emitting element. The red light LR has a first wavelength band, a second wavelength band, a third wavelength band including at least a wavelength belonging to red among the visible wavelength band, and a fourth wavelength band including at least a wavelength belonging to red. The third wavelength band is longer than the second wavelength band. The fourth wavelength band is longer than the third wavelength band.

[0099] In the first light source 20R of the lighting device 102, one first laser element 21R1 is disposed on the end surface 121e of the heat sink 121, and two or more second laser elements 21R1 are disposed at intervals from each other in the y direction. One second laser element 21R2 is disposed on the end surface 122e of the heat sink 122, and two or more second laser elements 21R2 are disposed at intervals from each other in the y direction. In the lighting device 102, the wavelength λR12 is equal to the wavelength λR11. That is, the single second laser element 21R2 emits red light LR of wavelength λR11 at the operating temperature T0. The size of each of the heat sinks 121 and 122 in the x direction is, for example, about 1 / 4 of the size of the light combining member 24 in the x direction.

[0100] The third laser element 21R3 corresponds to a third light emitting element. The third laser element 21R3 alone emits red light LR with a wavelength λR13 at an operating temperature T0. The wavelength λR3 is included in the third wavelength band of the red light LR. The wavelength λR13 is, for example, longer than the wavelength λR11.

[0101] The third heat dissipation member 213 is disposed on the side opposite to the x-direction from the second heat dissipation member 212, and is disposed within a range overlapping with the first heat dissipation member 211 in the z-direction. The third heat dissipation member 213 receives heat from the third laser element 21R3. That is, the heat of the third laser element 21R3 is transferred to the third heat dissipation member 213.

[0102] The third heat dissipation member 213 is, for example, a heat sink 123 made of a rectangular parallelepiped, and has two rectangular end faces parallel to each other and four side faces connecting the four sides of the two end faces. The two end faces of the heat sink 123 are, for example, parallel to the xy plane. Two of the four side faces of the heat sink 123 are parallel to the xz plane. The other two of the four side faces of the heat sink 123 are parallel to the yz direction. For example, one third laser element 21R3 is arranged in the x direction on the end face 123e on the z direction side of the two end faces of the heat sink 123, and two or more third laser elements 21R3 are arranged at intervals from each other in the y direction. The end face 123e is the surface of the heat sink 123 that faces the light combining member 24.

[0103] The light emitting surface of the third laser element 21R3 is parallel to the xy plane and is the surface opposite to the surface of the third laser element 21R3 that contacts the end surface 123e of the heat sink 123. The third laser element 21R3 is heated by a voltage supplied from a power supply device (not shown) during light emission. At least a part of the heat of the third laser element 21R3 is dissipated by the adjacent heat sink 123. The third laser element 21R3 emits red light LR3 with a wavelength λR3 at an operating temperature T3 lower than the operating temperature T2. The wavelength λR3 is included in the third wavelength band of the red light LR and is longer than the wavelengths λR1, λR2, and λR13. That is, the wavelength of the red light LR3 emitted by the third laser element 21R3 increases from the wavelength λR13 to the wavelength λR3 as the operating temperature of the third laser element 21R3 increases. The heat sink 123 has a heat dissipation capability to stabilize the temperature of the third laser element 21R3 at the operating temperature T3 during light emission. The sizes of the heat sink 123 in the x-direction, y-direction, and z-direction are set so that the heat sink 123 exhibits the heat dissipation capability to stabilize the temperature of the multiple third laser elements 21R3 at the operating temperature T3 during light emission.

[0104] The heat dissipation capacity of the heat sink 123, which is the third heat dissipation member 213, is different from the heat dissipation capacity of each of the heat sinks 121 and 122. For example, since the operating temperature T3 is higher than the operating temperature T1 and lower than the operating temperature T2, (T2-T0)>(T3-T0)>(T1-T0). In this case, the heat dissipation capacity of the heat sink 123 is smaller than the heat dissipation capacity of the heat sink 121 and larger than the heat dissipation capacity of the heat sink 122. Specifically, the size of the heat sink 123 in the x direction and the y direction is equal to the size of the heat sinks 121 and 122 in the x direction and the y direction. The size of the heat sink 123 in the z direction is smaller than the size of the heat sink 121 in the z direction and larger than the size of the heat sink 122 in the z direction.

[0105] The fourth laser element 21R4 corresponds to a fourth light emitting element. The fourth laser element 21R4 alone emits red light LR with a wavelength λR14 at the operating temperature T0. In the lighting device 102, the wavelength λR14 is equal to the wavelength λR13. That is, the fourth laser element 21R4 alone emits red light LR with a wavelength λR13 at the operating temperature T0.

[0106] The fourth heat dissipation member 214 is disposed on the opposite side of the second heat dissipation member 212 in the x direction, and is disposed within a range overlapping with the first heat dissipation member 211 in the z direction. The fourth heat dissipation member 214 receives heat from the fourth laser element 21R4. That is, the heat of the fourth laser element 21R4 is transferred to the fourth heat dissipation member 214.

[0107] The fourth heat dissipation member 214 is, for example, a heat sink 124 made of a rectangular parallelepiped, and has two parallel rectangular end faces and four side faces connecting the four sides of the two end faces. The two end faces of the heat sink 124 are, for example, parallel to the xy plane. Two of the four side faces of the heat sink 124 are parallel to the xz plane. The other two of the four side faces of the heat sink 124 are parallel to the yz direction. For example, one fourth laser element 21R4 is arranged in the x direction on the end face 124e on the z direction side of the two end faces of the heat sink 124, and two or more fourth laser elements 21R4 are arranged at intervals from each other in the y direction. The end face 124e is the surface of the heat sink 124 that faces the light combining member 24.

[0108] The light emitting surface of the fourth laser element 21R4 is parallel to the xy plane, and is the surface opposite to the surface of the fourth laser element 21R4 that contacts the end surface 124e of the heat sink 124. The fourth laser element 21R4 is heated by a voltage supplied from a power supply device (not shown) during light emission. At least a part of the heat of the fourth laser element 21R4 is dissipated by the adjacent heat sink 124. The fourth laser element 21R4 emits red light LR4 with a wavelength λR4 at an operating temperature T4 that is higher than the operating temperature T2. The wavelength λR4 is included in the fourth wavelength band of the red light LR, and is longer than the wavelengths λR1, λR2, and λR13, and is longer than the wavelength λR3. That is, the wavelength of the red light LR4 emitted by the fourth laser element 21R4 increases from the wavelength λR13 to the wavelength λR4 as the operating temperature of the fourth laser element 21R4 increases. The heat sink 124 has a heat dissipation capability to stabilize the temperature of the fourth laser element 21R4 at the operating temperature T4 during light emission. The sizes of the heat sink 124 in the x-direction, y-direction, and z-direction are set so that the heat sink 124 exhibits the heat dissipation capability to stabilize the temperature of the plurality of fourth laser elements 21R4 at the operating temperature T4 during light emission.

[0109] The heat dissipation capacity of the heat sink 124, which is the fourth heat dissipation member 214, is different from that of the heat sink 123. For example, since the operating temperature T4 is higher than the operating temperatures T1, T2, and T3, (T4-T0)>(T2-T0)>(T3-T0)>(T1-T0). In this case, the heat dissipation capacity of the heat sink 124 is smaller than that of the heat sink 122. Specifically, the size of the heat sink 124 in the x and y directions is equal to the size of the heat sinks 121 and 122 in the x and y directions. The size of the heat sink 124 in the z direction is smaller than the size of the heat sink 122 in the z direction.

[0110] The third laser element 21R3 emits red light LR3 radially from the light receiving surface with the z direction as the center. The fourth laser element 21R4 emits red light LR4 radially from the light receiving surface with the z direction as the center. As an example, the wavelength λR11 of the first laser element 21R1 and the second laser element 21R2 at the operating temperature T0 is 638 nm, and the wavelength λR13 of the third laser element 21R3 and the fourth laser element 21R4 at the operating temperature T0 is 642 nm. The operating temperature T1 is 40° C., and the wavelength λR1 of the first laser element 21R1 at the operating temperature T1 is 639 nm. The operating temperature T2 is 50° C., and the wavelength λR2 of the second laser element 21R2 at the operating temperature T2 is 641 nm. The operating temperature T3 is 45° C., and the wavelength λR3 of the third laser element 21R3 at the operating temperature T3 is 644 nm. The operating temperature T4 is 55° C., and the wavelength λR4 of the fourth laser element 21R4 at the operating temperature T4 is 646 nm.

[0111] In the above case, the wavelength difference (λR13-λR11) between the oscillation peak wavelength of the first laser element 21R1 alone and the oscillation peak wavelength of the fourth laser element 21R4 alone at the operating temperature T0 is 4 nm. A heat sink 123 is connected to the third laser element 21R3, and a heat sink 124 is connected to the fourth laser element 21R4. Therefore, the wavelength difference (λR4-λR1) between the red light LR1 of the first wavelength band emitted from the first laser element 21R1 at the operating temperature T1 and the red light LR4 of the fourth wavelength band emitted from the fourth laser element 21R4 at the operating temperature T4 is 7 nm, which is larger than the wavelength difference (λR13-λR11).

[0112] Furthermore, as the operation of the illumination device 102 continues, the temperatures of the first laser element 21R1 to the fourth laser element 21R4 rise, and the first light source 20R changes from a state in which it emits red light LR of two wavelengths λR11 and λR13 at the operating temperature T0 to a state in which it emits red light LR of four wavelengths λR1, λR2, λR3, and λR4. That is, the types of wavelengths included in the red light LR increase from two to four.

[0113] The number of the first collimating lenses 22R is the same as the total number of the first laser element 21R1, the second laser element 21R2, the third laser element 21R3, and the fourth laser element 21R4. The first collimating lenses 22R are arranged on the optical path of the red light LR1 emitted from the first laser element 21R1, on the optical path of the red light LR2 emitted from the second laser element 21R2, on the optical path of the red light LR3 emitted from the third laser element 21R3, and on the optical path of the red light LR4 emitted from the fourth laser element 21R4. The center of the first collimating lens 22R in the x direction is approximately overlapped with any of the center of the light emitting surface of the first laser element 21R1 corresponding to the first collimating lens 22R, the center of the light emitting surface of the second laser element 21R2, the center of the light emitting surface of the third laser element 21R3, and the center of the light emitting surface of the fourth laser element 21R4.

[0114] The first collimator lens 22R collimates any one of the incident red light beams LR1, LR2, LR3, and LR4. The red light beams LR1, LR2, LR3, and LR4 collimated by the first collimator lens 22R travel along the z direction. The optical axis AX1 of the red light beam LR emitted from the first light source 20R is parallel to the z direction.

[0115] The second light source 20G is disposed on the opposite side in the x direction from the first light source 20R. The second light source 20G has a laser element 21G and a second collimator lens 22G, and emits green light LG.

[0116] The second light source 20G has, for example, four laser elements 21G. The four laser elements 21G are arranged at intervals in the z direction. The light emitting surface of each laser element 21G is parallel to the yz plane. The laser element 21G emits green light LG radially in the x direction from the z direction.

[0117] The number of second collimator lenses 22G is the same as the total number of laser elements 21G. The second collimator lenses 22G are disposed on the optical path of the green light LG emitted from each laser element 21G. The center of the second collimator lens 22G in the x direction substantially overlaps with the center of the light emitting surface of the laser element 21G corresponding to the second collimator lens 22G.

[0118] The second collimator lens 22G collimates the incident green light LG. The green light LG collimated by the second collimator lens 22G travels along the x direction. The optical axis AX2 of the green light LG emitted from the second light source 20G is parallel to the x direction. The optical axis AX2 of the green light LG is perpendicular to the optical axis AX1 of the red light LR.

[0119] As described in the first embodiment, in the case where speckle noise due to green light LG becomes apparent, the second light source 20G may be configured similarly to the first light source 20R and include laser elements 21G that emit green light LG with different wavelengths at the operating temperature T0, and a heat dissipation member that is connected to the laser element 21G to transfer heat from the laser element 21G.

[0120] The illumination device 102 of the second embodiment described above includes a first light source 20R, a second light source 20G, a light combining member 24, a diffusion device 40, a condensing element 25, and a collimating element 26. According to the illumination device 102 of the second embodiment, similarly to the illumination device 2 of the first embodiment, when the white light WL emitted from the illumination device 2 is projected, speckle noise occurring in the projected image can be effectively reduced.

[0121] In the illumination device 102 of the second embodiment, the first light source 20R further includes a plurality of third laser elements (third light-emitting elements) 21R3, a plurality of fourth laser elements (fourth light-emitting elements) 21R4, a third heat dissipation member 213, and a fourth heat dissipation member 214. The third laser element 21R3 emits red light LR3 in a third wavelength band. The fourth laser element 21R4 emits red light LR4 in a fourth wavelength band different from the third wavelength band. Heat from the plurality of third laser elements 21R3 is transferred to the third heat dissipation member 213. Heat from the plurality of fourth laser elements 21R4 is transferred to the fourth heat dissipation member 214. The first wavelength band is shorter than the second wavelength band, and the third wavelength band is shorter than the fourth wavelength band. The first wavelength band and the second wavelength band are shorter than the third wavelength band and the fourth wavelength band. The heat dissipation capacity of the first heat dissipation member 211 is greater than the heat dissipation capacity of the second heat dissipation member 212 and is also greater than the heat dissipation capacity of the third heat dissipation member 213. The heat dissipation capacity of the second heat dissipation member 212 is greater than the heat dissipation capacity of the fourth heat dissipation member 214 and is equal to or less than the heat dissipation capacity of the third heat dissipation member 213. The heat dissipation capacity of the third heat dissipation member 213 is greater than the heat dissipation capacity of the fourth heat dissipation member 214.

[0122] In the illumination device 102 of the second embodiment, the first laser element 21R1 emits red light LR1 at an operating temperature T1 due to heat dissipation by the first heat dissipation member 211. The second laser element 21R2 emits red light LR2 at an operating temperature T2 due to heat dissipation by the second heat dissipation member 212. The third laser element 21R3 emits red light LR3 at an operating temperature T3 due to heat dissipation by the third heat dissipation member 213. The fourth laser element 21R4 emits red light LR4 at an operating temperature T4 due to heat dissipation by the fourth heat dissipation member 214. As a result, the number of wavelengths of the red light LR included in the white light WL diffused by the diffusion device 40 and incident on the integrated optical system 50 increases to four, and the wavelength difference (λR4-λR1) in the red light LR becomes larger than the wavelength difference (λR14-λR11), and the speckle noise of the white light WL is effectively reduced. According to the illumination device 102 of the second embodiment, when the white light WL emitted from the illumination device 2 is projected, speckle noise occurring in the projected image can be favorably and effectively reduced.

[0123] Furthermore, in the illumination device 102 of the second embodiment, in addition to the wavelength difference of the red light LR being enlarged as described above, the wavelength of the red light LR is multiplexed. The wavelength band of the red light LR is multiplexed into four wavelength bands from the first wavelength band to the fourth wavelength band of the red light LR1, LR2, LR3, and LR4. Therefore, according to the illumination device 102 of the second embodiment, the wavelength band of the red light LR becomes broader than when the wavelength of the red light LR is multiplexed into two wavelength bands, the first wavelength band of the red light LR1 and the second wavelength band of the red light LR2, as in the illumination device 2 of the first embodiment, and the speckle noise of the white light WL can be reduced favorably.

[0124] In the first light source 20R of the illumination device 102 of the second embodiment, the arrangement of the first laser element 21R1 and the first heat dissipation member 211, the second laser element 21R2 and the second heat dissipation member 212, the third laser element 21R3 and the third heat dissipation member 213, and the fourth laser element 21R4 and the fourth heat dissipation member 214 in the x direction may be freely changed. For example, the first laser element 21R1 and the first heat dissipation member 211, the second laser element 21R2 and the second heat dissipation member 212, the third laser element 21R3 and the third heat dissipation member 213, and the fourth laser element 21R4 and the fourth heat dissipation member 214 may be arranged in order along the x direction. In any arrangement, the same action and effect as the illumination device 102 of the second embodiment described above can be obtained.

[0125] In the lighting device 2 of the first embodiment, the number of the third laser elements 21R3 in the x direction and the number of the fourth laser elements 21R4 in the x direction and the number of the fourth laser elements 21R4 in the end face 124e of the heat sink 124 may be changed and set appropriately.

[0126] Third embodiment Next, a lighting device according to a third embodiment of the present invention will be described with reference to Fig. 5 to Fig. 8. In the description of the third embodiment, the contents common to the first and second embodiments are omitted, and only the configurations and contents different from the configurations already described in the first and second embodiments are described.

[0127] Fig. 5 is a perspective view showing a configuration of a first light source 20R of an illumination device of a third embodiment. Fig. 6 is a plan view of a first light source 20R of an illumination device of a third embodiment. In the third embodiment, the first light source 20R has a plurality of first laser elements 21R1, a plurality of second laser elements 21R2, a plurality of third laser elements 21R3, a first heat dissipation member 211, a second heat dissipation member 212, a third heat dissipation member 213, and a first collimating lens 22R. In Figs. 5 and 6, the first collimating lens 22R is omitted.

[0128] In the third embodiment, each of the multiple first laser elements 21R1, the multiple second laser elements 21R2, and the multiple third laser elements 21R3 is configured as one package.

[0129] 5 and 6, the multiple first laser elements 21R1 are mounted on a plate surface 141f parallel to the yz plane of a package base substrate 141. For example, five first laser elements 21R1 are arranged at intervals in the y direction on the plate surface 141f of the base substrate 141. Circuits and electronic components (not shown) for driving the first laser elements 21R1 are arranged on the plate surface 141f of the base substrate 141. The light emitting surface of the first laser element 21R1 is provided on an end surface parallel to the xy plane on the z direction side.

[0130] The base substrate 141 is connected to an end surface 121e of the heat sink 121, which is the first heat dissipation member 211. The heat of the five first laser elements 21R1 is transferred to the heat sink 121 via the base substrate 141.

[0131] The second laser elements 21R2 are mounted on a plate surface 142f parallel to the yz plane of a package base substrate 142. For example, five second laser elements 21R2 are arranged at intervals in the y direction on the plate surface 142f of the base substrate 142. Circuits and electronic components (not shown) for driving the second laser elements 21R2 are arranged on the plate surface 142f of the base substrate 142. The light emitting surface of the second laser element 21R2 is provided on an end surface parallel to the xy plane on the z direction side.

[0132] The base substrate 142 is connected to an end surface 122e of the heat sink 122 which is the second heat dissipation member 212. The heat of the five second laser elements 21R2 is transferred to the heat sink 122 via the base substrate 142.

[0133] The third laser elements 21R3 are mounted on a plate surface 143f parallel to the yz plane of a package base substrate 143. For example, five third laser elements 21R3 are arranged at intervals in the y direction on the plate surface 143f of the base substrate 143. Circuits and electronic components (not shown) for driving the third laser elements 21R3 are arranged on the plate surface 143f of the base substrate 143. The light emitting surface of the third laser element 21R3 is provided on an end surface parallel to the xy plane on the z direction side.

[0134] The base substrate 143 is connected to an end surface 123e of the heat sink 123 which is the third heat dissipation member 213. The heat of the five third laser elements 21R3 is transferred to the heat sink 123 via the base substrate 143.

[0135] As shown in FIG. 6, the widths WTH1 in the x direction of the heat sinks 121, 122, and 123 are the same as each other. The length LTH2 in the z direction of the heat sink 122 is shorter than the length LTH1 in the z direction of the heat sink 121. The length LTH3 in the z direction of the heat sink 123 is even shorter than the length LTH2 in the z direction of the heat sink 122. The heights in the y direction of the heat sinks 121, 122, and 123 are the same as each other. The lengths in the z direction of the base substrates 141, 142, and 143 are appropriately adjusted according to the relative positions of the end faces 121e, 122e, and 123e of the heat sinks 121, 122, and 123, for example, so that the light emitting surface of the first laser element 21R1, the light emitting surface of the second laser element 21R2, and the light emitting surface of the third laser element 21R3 are arranged at the same positions in the z direction.

[0136] Fig. 7 is a perspective view showing a configuration of a modified first light source 20R of the illumination device of the third embodiment. Fig. 8 is a plan view of a modified first light source 20R of the illumination device of the third embodiment. As a modified first light source 20R of the illumination device of the third embodiment, as shown in Figs. 7 and 8, the width WTH2 in the x direction of the heat sink 122 may be shorter than the width WTH1 in the x direction of the heat sink 121. The width WTH3 in the x direction of the heat sink 123 may be shorter than the width WTH2 in the x direction of the heat sink 122. The lengths LTH1, LTH2, and LTH3 in the z direction of the heat sinks 121, 122, and 123 are the same as each other.

[0137] In the illumination device of the third embodiment described above, the multiple first laser elements (first light-emitting elements) 21R1 are arranged one-dimensionally along the y direction. The multiple second laser elements (second light-emitting elements) 21R2 are arranged one-dimensionally along the y direction. The multiple first laser elements 21R1 and the multiple second laser elements 21R2 are separate from each other. The multiple first laser elements 21R1 are in one package. The multiple second laser elements 21R2 are in one package.

[0138] In the lighting device of the third embodiment, a plurality of first laser elements 21R1 are packaged, and a plurality of second laser elements 21R2 are packaged separately from the plurality of first laser elements 21R1, so that the first light source 20R can be easily configured by combining the first heat dissipation member 211 and the second heat dissipation member 212.

[0139] In the first light source 20R of the illumination device of the third embodiment, the number of the first collimating lenses 22R is the same as the total number of the first laser elements 21R1, the second laser elements 21R2, and the third laser elements 21R3. The first collimating lenses 22R may be disposed on the z-direction side of the light-emitting surface of each laser element as a separate entity from each of the packages of the first laser elements 21R1, the second laser elements 21R2, and the third laser elements 21R3, or may be mounted within each package of the laser element.

[0140] In the first light source 20R of the illumination device of the third embodiment, it is possible to adjust the paths of the red light LR1 emitted from the first laser elements 21R1, the red light LR2 emitted from the second laser elements 21R2, and the red light LR3 emitted from the third laser elements 21R3 in the x, y, and z directions. In that case, an optical element such as a mirror that refracts the red light LR may be appropriately disposed between the light emitting surface that emits the red light LR to be adjusted among the light emitting surfaces of the first laser elements 21R1, the light emitting surfaces of the second laser elements 21R2, and the light emitting surfaces of the third laser elements 21R3 and the light emitting surface of the third laser elements 21R3 and the light emitting surface that emits the red light LR to be adjusted in path and the incident surface of the light combining member 24 for the red light LR.

[0141] Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and changes are possible within the scope of the gist of the present invention described in the claims.

[0142] For example, the shape, number, arrangement, and material of each component of the illumination device and projector are not limited to those described in the above-described embodiment and modified examples, and may be changed as appropriate.

[0143] In the above embodiment, an example of a reflective diffusion device as a diffusion device is shown as an example of the illumination device of the present invention, but the present invention is not limited to this example. For example, the illumination device of the present invention may include a transmissive diffusion device as a diffusion device. In that case, a reflective film is not provided on the substrate of the diffusion device. The composite light diffused by the diffusion surface of the substrate of the diffusion device and transmitted through the substrate is emitted from the exit surface of the substrate along an optical axis aligned with the optical axis of the composite light incident on the substrate. In the above embodiment, since the diffusion device is a reflective diffusion device, the polarization of the composite light emitted from the diffusion device is less disturbed compared to the case of a transmissive diffusion device.

[0144] In the above embodiment, an example in which the illumination device of the present invention is mounted on a projector using a liquid crystal panel has been shown, but the present invention is not limited to this example. For example, the illumination device of the present invention may be applied to a projector using a digital micromirror device as a light modulation device. The projector of the present invention may not have a plurality of light modulation devices, and may be a single-panel projector having only one light modulation device.

[0145] [Summary of this disclosure] The following is a summary of this disclosure. (Additional Note 1) The present invention includes a diffusion device having a first light source that emits a first light of a first color, a second light source that emits a second light having a color different from the first light, a light combining member that combines the first light and the second light and emits a combined light, a substrate having a diffusion surface that diffuses and emits the combined light incident thereon, and a drive device that rotates the substrate, a focusing element that is disposed between the light combining member and the diffusion device and focuses the combined light on the diffusion surface of the diffusion device, and a collimating element that collimates the combined light emitted from the diffusion device. the first light source includes a plurality of first light-emitting elements that emit the first light in a first wavelength band, a plurality of second light-emitting elements that emit the first light in a second wavelength band different from the first wavelength band, a first heat dissipation member to which heat from the plurality of first light-emitting elements is transferred, and a second heat dissipation member to which heat from the plurality of second light-emitting elements is transferred, wherein a heat dissipation capacity of the first heat dissipation member and a heat dissipation capacity of the second heat dissipation member are different from each other.

[0146] According to the configuration of Supplementary Note 1, the wavelength difference between the first light emitted from the first light emitting element and the first light emitted from the second light emitting element is enlarged by the first heat dissipation member and the second heat dissipation member, and compared to conventional lighting devices, it is possible to cause a composite light with reduced speckle noise to enter the diffusion device and the downstream optical system. Therefore, according to the configuration of Supplementary Note 1, when the composite light emitted from the lighting device is projected, it is possible to effectively reduce speckle noise occurring in the projected image.

[0147] (Supplementary Note 2) The lighting device of Supplementary Note 1, wherein the first wavelength band is shorter than the second wavelength band, and the heat dissipation capacity of the first heat dissipation member is greater than the heat dissipation capacity of the second heat dissipation member.

[0148] With the configuration of Supplementary Note 2, the wavelength difference between the first light emitted from the first light-emitting element and the first light emitted from the second light-emitting element and having a longer wavelength band than the first light emitted from the first light-emitting element can be increased by the first heat dissipation member and the second heat dissipation member. Therefore, the diffusion, scattering or diffraction pattern and the speckle pattern in the spot of the combined light formed on the diffusion surface of the diffusion device can be changed over time.

[0149] (Appendix 3) The lighting device of Appendix 2, wherein the first heat dissipation member includes a first heat sink having a plurality of first fins, and the second heat dissipation member includes a second heat sink having a plurality of second fins, and a size of the first heat sink is larger than a size of the second heat sink.

[0150] With the configuration of Supplementary Note 3, the wavelength difference between the first light emitted from the first light emitting element and the first light emitted from the second light emitting element can be increased by the first heat dissipation member and the second heat dissipation member.

[0151] (Appendix 4) The lighting device of Appendix 2 or Appendix 3, wherein the first heat dissipation member includes a first heat sink having a plurality of first fins, and the second heat dissipation member includes a second heat sink having a plurality of second fins, and the number of the plurality of first fins is greater than the number of the plurality of second fins.

[0152] With the configuration of Supplementary Note 4, the wavelength difference between the first light emitted from the first light emitting element and the first light emitted from the second light emitting element can be increased by the first heat dissipation member and the second heat dissipation member.

[0153] (Supplementary Note 5) The lighting device of any one of Supplementary Notes 1 to 4, wherein the first heat dissipation member includes a first heat sink having a plurality of first fins and a third heat sink having a plurality of third fins, the second heat dissipation member includes a second heat sink having a plurality of second fins, and the first heat sink and the third heat sink are connected by a heat transport member.

[0154] With the configuration of Appendix 5, the third heat sink is thermally connected to the first heat sink, the wavelength of the red light emitted from the first light-emitting element is adjusted, and the wavelength difference between the first light emitted from the first light-emitting element and the first light emitted from the second light-emitting element can be increased by the first heat dissipation member and the second heat dissipation member.

[0155] (Supplementary Note 6) The lighting device of any one of Supplementary Notes 1 to 5, wherein the plurality of first light-emitting elements are arranged in a line-dimensional manner, the plurality of second light-emitting elements are arranged in a line-dimensional manner, the plurality of first light-emitting elements and the plurality of second light-emitting elements are separate from each other, the plurality of first light-emitting elements are in a single package, and the plurality of second light-emitting elements are in a single package.

[0156] According to the configuration of Supplementary Note 6, the first heat dissipation member can be easily connected to the packaged first light-emitting element, and the wavelength of the red light LR1 emitted from the first light-emitting element can be set and adjusted. The second heat dissipation member can be easily connected to the packaged second light-emitting element, and the wavelength of the red light LR2 emitted from the second light-emitting element can be set and adjusted.

[0157] (Additional Note 7) The first light source further includes a plurality of third light-emitting elements that emit the first light in a third wavelength band, a plurality of fourth light-emitting elements that emit the first light in a fourth wavelength band different from the third wavelength band, a third heat dissipation member to which heat of the plurality of third light-emitting elements is transferred, and a fourth heat dissipation member to which heat of the plurality of fourth light-emitting elements is transferred, wherein the first wavelength band is shorter than the second wavelength band, the third wavelength band is shorter than the fourth wavelength band, and the first wavelength band and the 7. The lighting device of any of Appendix 1 to Appendix 6, wherein the second wavelength band is shorter than the third wavelength band and the fourth wavelength band, the heat dissipation capacity of the first heat dissipation member is greater than the heat dissipation capacity of the second heat dissipation member and is greater than the heat dissipation capacity of the third heat dissipation member, the heat dissipation capacity of the second heat dissipation member is greater than the heat dissipation capacity of the fourth heat dissipation member and is equal to or less than the heat dissipation capacity of the third heat dissipation member, and the heat dissipation capacity of the third heat dissipation member is greater than the heat dissipation capacity of the fourth heat dissipation member.

[0158] The configuration of Supplementary Note 7 generates first light of four wavelength bands, and the maximum wavelength difference between the first light emitted from the first light emitting element and the first light emitted from the fourth light emitting element is expanded by the first heat dissipation member and the fourth heat dissipation member, so that compared to conventional lighting devices, composite light with reduced speckle noise can be made incident on the diffusion device and the downstream optical system. Therefore, according to the configuration of Supplementary Note 7, when the composite light emitted from the lighting device is projected, speckle noise generated in the projected image can be effectively reduced.

[0159] (Supplementary Note 8) The lighting device of any one of Supplementary Notes 1 to 7, wherein the first color is red.

[0160] Of the three primary colors, red light is the most likely to cause speckle noise. The configuration of Supplementary Note 8 allows the combined light with reduced speckle noise to be effectively incident on the diffusion device and the downstream optical system. Therefore, the configuration of Supplementary Note 8 allows the speckle noise generated in the projected image to be effectively reduced when the combined light emitted from the lighting device is projected.

[0161] (Supplementary Note 9) A projector comprising: an illumination device according to any one of Supplementary Note 1 to Supplementary Note 8; a light modulation device that modulates light emitted from the illumination device; and a projection optical system that projects the light modulated by the light modulation device.

[0162] According to the configuration of Supplementary Note 9, when the composite light emitted from the illumination device is converted into image light by the light modulation device and the image light is projected, speckle noise occurring in the projected image can be effectively reduced. [Explanation of symbols]

[0163] 1...projector, 2...lighting device, 20R...first light source, 20R1...first laser element (first light-emitting element), 20R2...second laser element (second light-emitting element), 20G...second light source, 24...light combining member, 25...collimating element, 26...collimating element, 40...diffusion device, 211...first heat dissipation member, 212...second heat dissipation member.

Claims

1. a first light source that emits a first light of a first color; a second light source that emits a second light having a color different from that of the first light; a light combining member that combines the first light and the second light and emits a combined light; a diffusion device including a substrate having a diffusion surface that diffuses the incident combined light and emits the combined light, and a drive device that rotates the substrate; a focusing element disposed between the light combining member and the diffusing device, the focusing element focusing the combined light on the diffusing surface of the diffusing device; a collimating element for collimating the combined light emitted from the diffusion device; Equipped with The first light source is A plurality of first light emitting elements that emit the first light in a first wavelength band; A plurality of second light-emitting elements that emit the first light in a second wavelength band different from the first wavelength band; a first heat dissipation member to which heat from the plurality of first light emitting elements is transferred; a second heat dissipation member to which heat from the plurality of second light emitting elements is transferred; having The heat dissipation capacity of the first heat dissipation member and the heat dissipation capacity of the second heat dissipation member are different from each other. Lighting equipment.

2. the first wavelength band is shorter than the second wavelength band; The heat dissipation capacity of the first heat dissipation member is greater than the heat dissipation capacity of the second heat dissipation member.

10. The lighting device of claim 1.

3. the first heat dissipation member includes a first heat sink having a plurality of first fins; the second heat dissipation member includes a second heat sink having a plurality of second fins; The size of the first heat sink is larger than the size of the second heat sink.

3. The lighting device according to claim 2.

4. the first heat dissipation member includes a first heat sink having a plurality of first fins; the second heat dissipation member includes a second heat sink having a plurality of second fins; The number of the first fins is greater than the number of the second fins.

3. The lighting device according to claim 2.

5. the first heat dissipation member includes a first heat sink having a plurality of first fins and a third heat sink having a plurality of third fins; the second heat dissipation member includes a second heat sink having a plurality of second fins; The first heat sink and the third heat sink are connected by a heat transfer member.

3. The lighting device according to claim 2.

6. The plurality of first light emitting elements are arranged in a line in one dimension, The plurality of second light emitting elements are arranged in a line in one dimension, The first light-emitting elements and the second light-emitting elements are separate from each other, The plurality of first light emitting elements are in one package, The plurality of second light-emitting elements are in one package. The lighting device according to claim 1 .

7. The first light source is a plurality of third light emitting elements that emit the first light in a third wavelength band; a plurality of fourth light-emitting elements that emit the first light in a fourth wavelength band different from the third wavelength band; a third heat dissipation member to which heat from the third light emitting elements is transferred; a fourth heat dissipation member to which heat from the plurality of fourth light emitting elements is transferred; and the first wavelength band is shorter than the second wavelength band; the third wavelength band is shorter than the fourth wavelength band; the first waveband and the second waveband are shorter than the third waveband and the fourth waveband; a heat dissipation capacity of the first heat dissipation member is greater than a heat dissipation capacity of the second heat dissipation member and is greater than a heat dissipation capacity of the third heat dissipation member; a heat dissipation capacity of the second heat dissipation member is greater than a heat dissipation capacity of the fourth heat dissipation member and is equal to or less than a heat dissipation capacity of the third heat dissipation member; The heat dissipation capacity of the third heat dissipation member is greater than the heat dissipation capacity of the fourth heat dissipation member. The lighting device according to claim 1 .

8. The first color is red. The lighting device according to claim 1 .

9. The lighting device according to any one of claims 1 to 5, a light modulation device that modulates light emitted from the illumination device; a projection optical system that projects the light modulated by the light modulation device; Equipped with projector.

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