Illumination device and projector

Abstract

A lighting device and a projector are provided. The present invention reduces speckle noise of a projected image in a projector provided with an illumination device. The lighting device includes: a first light source that emits first light; a second light source that emits second light having a color different from that of the first light; a light combining member that emits combined light of the first light and the second light; a diffusion device provided with a substrate having a diffusion surface for diffusing the synthesized light, and a drive device for rotating the substrate; a light condensing element disposed between the light combining member and the diffusion device and condensing the combined light to the diffusion surface; and a collimating element for parallelizing the combined light emitted from the diffusion device. The first light source includes: a plurality of first light-emitting elements that emit first light of a first wavelength band; a plurality of second light-emitting elements that emit first light of a second wavelength band different from the first wavelength band; a first heat dissipation member to which heat of the plurality of first light-emitting elements is transferred; and a second heat dissipation member to which heat of the plurality of second light-emitting elements is transferred. The heat dissipation capabilities of the first heat dissipation member and the second heat dissipation member are different from each other.

Description

Technical Field

[0001] The invention relates to a lighting device and a projector. Background Art

[0002] In recent years, in order to improve the performance of projectors, an illumination device including a laser light source as a light source with a wide color gamut and high efficiency, and a projector including such an illumination device have been proposed.

[0003] For example, in the projector disclosed in Patent Document 1, three colors of light emitted from a red light source array having a laser light source emitting red light, a green light source array having a laser light source emitting green light, and a blue light source array having a laser light source emitting blue light are synthesized by a color synthesis optical system, and the synthesized light is incident on a condenser lens and converged toward a diffusion plate. In the projector disclosed in Patent Document 1, the converged synthesized light passes through the diffusion plate, thereby reducing speckle noise generated in the projected image.

[0004] For example, the light source device disclosed in Patent Document 2 can be applied 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 element is shorter than that of the first laser element.

[0005] Patent Document 1: Japanese Patent Application Publication No. 2019-078906

[0006] Patent Document 2: Japanese Patent Application Publication No. 2021-057512

[0007] In the projector disclosed in Patent Document 1, the reduction of speckle noise is insufficient by merely irradiating the synthetic light focused by the condenser lens to the diffusion plate and emitting the diffused synthetic light from the diffusion plate, and improvement is desired. In the light source device disclosed in Patent Document 2, since the emission wavelength of the second laser element is shorter than the emission wavelength of the first laser element, the light emitted from each laser element is less likely to interfere with each other. In addition, 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 reduction of speckle noise is insufficient, and further improvement is desired. Summary of the invention

[0008] A lighting device according to one embodiment of the present invention comprises: a first light source that emits a first light of a first color; a second light source that emits a second light of a color different from that of the first light; a light synthesis component that synthesizes the first light and the second light to emit the synthesized light; a diffusion device having a substrate and a driving device, the substrate having a diffusion surface that diffuses and emits the incident synthesized light, the driving device rotating the substrate; and a focusing element that is arranged between the light synthesis component and the diffusion device and focuses the synthesized light on the diffusion device. on the diffusion surface; and a collimating element, which parallelizes the synthetic light emitted from the diffusion device, the first light source comprising: a plurality of first light-emitting elements, which emit the first light of a first wavelength band; a plurality of second light-emitting elements, which emit the first light of a second wavelength band different from the first wavelength band; a first heat dissipation component, to which the heat of the plurality of first light-emitting elements is transferred; and a second heat dissipation component, to which the heat of the plurality of second light-emitting elements is transferred, the heat dissipation capacity of the first heat dissipation component and the heat dissipation capacity of the second heat dissipation component are different from each other. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 This is a schematic diagram showing the structure of the projector according to the first embodiment.

[0010] Figure 2 yes Figure 1 A schematic diagram of the illumination device of a projector.

[0011] Figure 3 yes Figure 2 Schematic diagram of a substrate of a diffusion device of a lighting device.

[0012] Figure 4 This is a schematic diagram of a lighting device for a projector according to a second embodiment.

[0013] Figure 5 It is a perspective view of a lighting device for a projector according to a third embodiment.

[0014] Figure 6 yes Figure 5 A top view of a lighting device.

[0015] Figure 7 It is a perspective view of a modified example of the illumination device of the projector according to the third embodiment.

[0016] Figure 8 yes Figure 7 A top view of a lighting device.

[0017] Description of symbols

[0018] 1: projector; 2: lighting device; 20R: first light source; 21R1: first laser element (first light emitting element); 21R2: second laser element (second light emitting element); 20G: second light source; 24: photosynthesizing component; 25: focusing element; 26: collimating element; 40: diffusion device; 211: first heat dissipation component; 212: second heat dissipation component. DETAILED DESCRIPTION

[0019] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In each of the drawings, in order to make each component easier to see, the scale of the dimensions may be changed depending on the component.

[0020] (First embodiment)

[0021] First, refer to Figure 1 A projector 1 according to a first embodiment of the present invention will be described. Figure 1 1 is a schematic diagram showing the structure of a 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, 4B, a color synthesis optical system 5, and a projection optical system 6. The projector 1 is a three-panel projector having three light modulation devices.

[0022] 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 includes red light RL, green light GL, and blue light BL. The configuration of the illumination device 2 will be described later.

[0023] 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.

[0024] The first dichroic mirror 11 is arranged 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 the blue light BL. The second dichroic mirror 12 is arranged on the common optical path of the green light GL and the blue light BL emitted from the first dichroic mirror 11, and separates the green light GL and the blue light BL. The second dichroic mirror 12 transmits the blue light BL, and reflects the green light GL.

[0025] The first total reflection mirror 13 reflects the red light RL toward the light modulator 4R. The second total reflection mirror 14 and the third total reflection mirror 15 guide the blue light BL to the light modulator 4B. The green light GL is reflected from the second dichroic mirror 12 toward the light modulator 4G. The red light RL, the green light GL, and the blue light BL included in the white light WL correspond to the light emitted from the lighting device 2.

[0026] The first relay lens 16 is arranged 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 arranged on the optical path of the blue light BL between the second total reflection mirror 14 and the third total reflection mirror 15. By arranging the first relay lens 16 and the second relay lens 17 as described above, the optical loss of the blue light BL can be compensated. The optical loss of the blue light BL is caused by the fact that the optical path length of the blue light BL from the first dichroic mirror 11 to the light modulator 4B is longer than the optical path length of the red light RL from the first dichroic mirror 11 to the light modulator 4R and the optical path length of the green light GL from the first dichroic mirror 11 to the light modulator 4G.

[0027] The light modulator 4R is arranged 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 modulator 4R modulates the incident red light RL according to the image information input from the image input device (not shown), forms red image light, and emits the red image light. The light modulator 4G is arranged 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 modulator 4G modulates the incident green light GL according to the image information input from the image input device (not shown), forms green image light, and emits green image light. The light modulator 4B is arranged 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 modulator 4B modulates the incident blue light BL according to the image information input from the image input device (not shown), forms blue image light, and emits blue image light. The image input device is, for example, a personal computer or a portable terminal device.

[0028] The light modulators 4R, 4G, and 4B use, for example, transmissive liquid crystal panels. Polarizing plates (not shown) are disposed on the incident side and the emitting 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 modulator 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 modulator 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 modulator 4B.

[0029] The color synthesis optical system 5 is arranged across the optical path of the red image light emitted from the light modulator 4R, the optical path of the green image light emitted from the light modulator 4G, and the optical path of the blue image light emitted from the light modulator 4B. Figure 1 As shown, when viewed from above or from the side, the synthesis position of the colored 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 to form colored image light. The color synthesis optical system 5 emits colored image light. The color synthesis optical system 5 uses, for example, a cross dichroic prism.

[0030] The projection optical system 6 is arranged on the optical path of the colored image light emitted from the color synthesis optical system 5. The colored image light emitted from the color synthesis optical system 5 is equivalent to the light modulated by the light modulating devices 4R, 4G, and 4B. The projection optical system 6 enlarges and projects the colored image light emitted from the color synthesis optical system 5 and incident toward the screen SCR. The colored image light enlarged and projected from the projection optical system 6 is displayed as a color image on a display surface opposite to the emission surface of the projection optical system 6 in the screen SCR.

[0031] The projection optical system 6 is composed of, for example, a plurality of optical lenses, but may be composed of one optical lens. The optical lens includes, for example, various lenses such as a plano-convex lens, a biconvex lens, a meniscus lens, an aspherical lens, a rod lens, and a free-form surface lens.

[0032] Next, refer to Figure 2 and Figure 3 A lighting device 2 according to a first embodiment of the present invention will be described. Figure 2 2 is a schematic diagram showing the structure of the lighting device 2. The lighting 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 diffuser 40, a collimator 26, and an integrator optical system 50.

[0033] The first light source 20R includes a first laser element 21R1, a second laser element 21R2, a first heat sink 211, a second heat sink 212, and a first collimating lens 22R, and emits red light LR. The red light LR corresponds to the first light. The red light LR includes a first wavelength band that includes at least a wavelength belonging to red in the visible wavelength band, and a second wavelength band that also includes a wavelength belonging to red and is longer than the first wavelength band. Red corresponds to the first color. The red light LR includes, for example, a wavelength band of 585 nm to 720 nm.

[0034] The first laser element 21R1 is equivalent to the first light emitting element. The single first laser element 21R1 emits red light LR with a wavelength λR11 at an operating temperature T0. The operating temperature T0 is, for example, 25°C, which is a temperature within the room temperature range and is a symbolic temperature when indicating the specifications and characteristics of the laser element. The wavelength λR11 is included in the first wavelength band of the red light LR.

[0035] The first heat dissipation component 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 component 211. The first heat dissipation component 211 is, for example, a heat sink 121 formed of a rectangular parallelepiped, having two rectangular end faces parallel to each other and four side faces connecting the four sides of the two end faces to each other. The heat sink 121 is equivalent 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 orthogonal 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 orthogonal 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 plane including the y-direction and the z-direction. On the end surface 121e on the z-direction side of the two end surfaces of the heat sink 121, 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. The end surface 121e is a surface of the heat sink 121 that faces the light combining member 24.

[0036] The light emitting surface of the first laser element 21R1 is parallel to the xy plane and is the surface on the opposite side of the surface of the first laser element 21R1 that contacts the end surface 121e of the heat sink 121. When emitting light, the first laser element 21R1 is heated by a voltage supplied from a power supply device (not shown). At least a portion of the heat of the first laser element 21R1 is dissipated through the adjacent heat sink 121. The first laser element 21R1 emits red light LR1 having a wavelength λR1 at an operating temperature T1 that is 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.

[0037] The heat sink 121 has a heat dissipation capability to stabilize the temperature of the first laser element 21R1 at the operating temperature T1 when emitting light. The sizes of the heat sink 121 in the x direction, the y direction, and the z direction are set so that the heat sink 121 exhibits a heat dissipation capability to stabilize the temperature of the plurality of first laser elements 21R1 at the operating temperature T1 when emitting light. The size of the heat sink 121 in the x direction is, for example, about half the size of the light combining component 24 in the x direction described later. The size of the heat sink 121 in the y direction is, for example, about the same as the size of the light combining component 24 in the y direction.

[0038] The first laser element 21R1 emits red light LR1 radially from the light emitting 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, and the operating temperature T1 is 45° C., and the wavelength λR1 at the operating temperature T1 is 640 nm.

[0039] The second laser element 21R2 corresponds to the second light emitting element. The second laser element 21R2 alone emits red light LR of wavelength λR12 at operating temperature T0. The wavelength λR12 is different from at least the wavelength λR11 and is included in the second wavelength band of the red light LR. The wavelength λR12 is, for example, longer than the wavelength λR11.

[0040] The second heat sink 212 is disposed on the opposite side of the x direction from the first heat sink 211 and in the z direction within a range overlapping with the first heat sink 211. The second heat sink 212 receives heat from the second laser element 21R2. In other words, the heat of the second laser element 21R2 is transferred to the second heat sink 212.

[0041] The second heat dissipation component 212 is, for example, a heat sink 122 formed of a rectangular parallelepiped, having two rectangular end faces parallel to each other and four side faces connecting the four sides of the two end faces to each other. The heat sink 122 is equivalent to the 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 plane. On the end face 122e on the z-direction side of the two end faces of the heat sink 122, for example, two second laser elements 21R2 are arranged at intervals from each other in the x-direction, 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 face of the heat sink 122 facing the photosynthetic component 24.

[0042] The light emitting surface of the second laser element 21R2 is parallel to the xy plane, and is the surface on the opposite side of the surface of the second laser element 21R2 that contacts the end surface 122e of the heat sink 122. When emitting light, the second laser element 21R2 is heated by a voltage supplied from a power supply device (not shown). At least a portion of the heat of the second laser element 21R2 is dissipated through 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.

[0043] The heat sink 122 has a heat dissipation capability to stabilize the temperature of the second laser element 21R2 at the operating temperature T2 when emitting light. The sizes of the heat sink 122 in the x direction, the y direction, and the z direction are set so that the heat sink 122 exhibits a heat dissipation capability to stabilize the temperature of the plurality of second laser elements 21R2 at the operating temperature T2 when emitting light.

[0044] The heat dissipation capacity of the heat sink 122 as the second heat dissipation component 212 is different from the heat dissipation capacity of the heat sink 121 as the first heat dissipation component 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 as the second heat dissipation component 212 is smaller than the heat dissipation capacity of the heat sink 121 as the first heat dissipation component 211. Specifically, the size of the heat sink 122 in the x direction and the y direction is the same as 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.

[0045] The second laser element 21R2 emits red light LR2 radially from the light emitting 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 642nm, and the operating temperature T2 is 55°C, and the wavelength λR2 at the operating temperature T2 is 646nm. As described above, when the wavelength λR11 of the first laser element 21R1 at the operating temperature T0 is 638nm, and the wavelength λR1 at the operating temperature T1 is 640nm, the wavelength difference (λR12-λR11) between the oscillation peak wavelength of the single first laser element 21R1 at the operating temperature T0 and the oscillation peak wavelength of the single second laser element 21R2 is 4nm. The first laser element 21R1 is connected to the heat sink 121, and the second laser element 21R2 is connected to the heat sink 122. Therefore, the wavelength difference (λR2-λR1) between the first wavelength band red light LR1 emitted from the first laser element 21R1 at the operating temperature T1 and the second wavelength band red light LR2 emitted from the second laser element 21R2 at the operating temperature T2 is 6 nm, which is larger than the wavelength difference (λR12-λR11).

[0046] That is, as the operation of the lighting 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 emitting two kinds of red light LR, wavelengths λR11 and λR12, with a wavelength difference of 4 nm at the operating temperature T0 to emitting two kinds of red light LR, wavelengths λR1 and λR2, with a wavelength difference of 6 nm. That is, the difference between the two wavelengths increases.

[0047] The number of the first collimator lenses 22R is the same as the total number of the first laser elements 21R1 and the second laser elements 21R2. The first collimator lenses 22R are arranged on the optical path of the red light LR1 emitted from each first laser element 21R1, and on the optical path of the red light LR2 emitted from each second laser element 21R2. In the first collimator lens 22R, the center in the x direction substantially overlaps with the center of the light emitting surface of the first laser element 21R1 or the center of the light emitting surface of the second laser element 21R2 corresponding to the first collimator lens 22R.

[0048] 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.

[0049] The second light source 20G is arranged on the z-direction side relative to the first light source 20R, and on the direction side opposite to the x-direction relative to the first light source 20R. The second light source 20G has a first laser element 21G1, a second laser element 21G2, a first heat sink 221, a second heat sink 222, and a second collimating lens 22G, and emits green light LG. The green light LG corresponds to the second light. The green light LG has a first band that includes at least a wavelength belonging to green in the visible band, and a second band that also includes a wavelength belonging to green and is longer than the first band. Green corresponds to the second color, and is a color different from red, which is the first color. The green light LG has a band of 495nm to 585nm, for example.

[0050] The single first laser element 21G1 emits green light LG having a wavelength λG11 at an operating temperature T0. The wavelength λG11 is included in the first wavelength band of the green light LG.

[0051] 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 formed 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 to each other. 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 plane. On the end face 131e on the x-direction side of the two end faces of the heat sink 131, for example, two first laser elements 21G1 are arranged at intervals from each other in the z direction, and two or more first laser elements 21G1 are arranged at intervals from each other in the y direction. The end face on which the two first laser elements 21G1 are provided is a face of the heat sink 131 that faces the light synthesizing member 24.

[0052] The light emitting surface of the first laser element 21G1 is parallel to the yz plane. When emitting light, the first laser element 21G1 is heated by a voltage supplied from a power supply device (not shown). At least a portion of the heat of the first laser element 21G1 is dissipated through the adjacent heat sink 131. The first laser element 21G1 emits green light LG1 having 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.

[0053] The heat sink 131 has a heat dissipation capability to stabilize the temperature of the first laser element 21G1 at the operating temperature T11 when emitting light. The sizes of the heat sink 131 in the x direction, y direction, and z direction are set so that the heat sink 131 exhibits a heat dissipation capability to stabilize the temperature of the plurality of first laser elements 21G1 at the operating temperature T11 when emitting light. The size of the heat sink 131 in the z direction is, for example, about half the size of the light combining component 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 component 24 in the y direction.

[0054] The first laser element 21G1 emits the green light LG1 radially with the x direction as the center.

[0055] The second laser element 21G2 as a single body emits green light LG having a wavelength λG12 at the operating temperature T0. The wavelength λG12 is different from at least the wavelength λG11 and is included in the second wavelength band of the green light LG. The wavelength λG12 is longer than the wavelength λG11, for example.

[0056] The second heat sink 222 is disposed closer to the z-direction side than the first heat sink 221 and in the x-direction within a range overlapping the first heat sink 221. The second heat sink 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 sink 222.

[0057] The second heat dissipation component 222 is, for example, a heat sink 132 formed of a rectangular parallelepiped, having two rectangular end faces parallel to each other and four side faces connecting the four sides of the two end faces to each other. 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 plane. On the end face 132e on the x-direction side of the two end faces of the heat sink 132, for example, two second laser elements 21G2 are arranged at intervals from each other in the z-direction, 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 photosynthetic component 24.

[0058] The light emitting surface of the second laser element 21G2 is parallel to the yz plane. When emitting light, the second laser element 21G2 is heated by a voltage supplied from a power supply device (not shown). At least a portion of the heat of the second laser element 21G2 is dissipated through the adjacent heat sink 132. The second laser element 21G2 emits green light LG2 with a wavelength of λG2 at an operating temperature T12 that is 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 capability to stabilize the temperature of the second laser element 21G2 at the operating temperature T12 when emitting light. The sizes of the heat sink 132 in the x direction, the y direction, and the z direction are set so that the heat sink 132 exhibits a heat dissipation capability that stabilizes the temperature of the plurality of second laser elements 21G2 at the operating temperature T12 when emitting light.

[0059] The heat dissipation capacity of the heat sink 132 as the second heat dissipation component 222 is different from the heat dissipation capacity of the heat sink 131 as the first heat dissipation component 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 as the second heat dissipation component 222 is smaller than the heat dissipation capacity of the heat sink 131 as the first heat dissipation component 221. Specifically, the size of the heat sink 132 in the y direction and the z direction is the same as 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.

[0060] The second laser element 21G2 emits green light LG2 radially from the light emitting surface with the x direction as the center. The first laser element 21G1 is connected to a heat sink 131, and the second laser element 21G2 is connected to a heat sink 132. Therefore, the wavelength difference (λG2-λG1) between the green light LG1 of the first wavelength band emitted from the first laser element 21G1 at an operating temperature T11 and the green light LG2 of the second wavelength band emitted from the second laser element 21G2 at an operating temperature T12 is larger than the wavelength difference (λG12-λG11) between the oscillation peak wavelength of the single first laser element 21G1 and the oscillation peak wavelength of the single second laser element 21G2 at an operating temperature T0.

[0061] That is, as the operation of the lighting 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 emitting two types of green light LG of wavelengths λG11 and λG12 at the operating temperature T0 to emitting two types of green light LG of wavelengths λG1 and λG2. That is, the difference between the two wavelengths increases.

[0062] The number of the second collimating lenses 22G is the same as the total number of the first laser elements 21G1 and the second laser elements 21G2. The second collimating lenses 22G are arranged on the optical path of the green light LG1 emitted from each first laser element 21G1, and on the optical path of the green light LG2 emitted from each second laser element 21G2. The center of the second collimating lens 22G in the z direction substantially overlaps with the center of the light emitting surface of the first laser element 21G1 or the center of the light emitting surface of the second laser element 21G2 corresponding to the second collimating lens 22G.

[0063] The second collimator lens 22G collimates the incident green light LG1 and LG2. The green light LG1 and LG2 collimated by the second collimator lens 22G travel 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.

[0064] The third light source 20B is arranged on the z-direction side relative to the second light source 20G, and is arranged in 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 collimating lens 22B, and emits blue light LB. The blue light LB has a wavelength band including at least a wavelength 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 380nm to 495nm, for example.

[0065] 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 in the direction opposite to the z direction with the z direction as the center.

[0066] The number of collimator lenses 22B is the same as the total number of laser elements 21B. Collimator lenses 22B are arranged on the optical path of blue light LB emitted from each laser element 21B. The center of the collimator lens 22B in the x direction roughly overlaps with the center of the light emitting surface of the laser element 21B corresponding to the collimator lens 22B.

[0067] The collimator lens 22B collimates the incident blue light LB. The blue light LB collimated by the collimator lens 22B travels in a 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.

[0068] The optical axis AX1 of the blue light LB and the optical axis AX1 of the red light LR are located on the same line, and the optical axis AX1 of the red light LR is extended toward the photosynthetic component 24 in a manner passing through the synthesis position of the color lights in the photosynthetic component 24 and further extended relative to the photosynthetic component 24 to the side opposite to the first light source 20R.

[0069] In addition, each of the first light source 20R, the second light source 20G, and the third light source 20B may include components other than various laser light sources, collimating lenses, and various heat dissipating components, such as a package that holds various laser light sources and collimating lenses.

[0070] The light combining member 24 is arranged so as to straddle 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. Figure 2 As shown, when viewed from above or from the side, the position where the colored lights are combined in the photosynthesizing component 24 overlaps with the intersection of the optical paths of the red light LR, the green light LG, and the blue light LB, that is, the intersection of the optical axis AX1 and the optical axis AX2.

[0071] In the light synthesis component 24, the incident red light LR, green light LG and blue light LB are synthesized to generate white light WL. The white light WL is equivalent to the synthesized light. The light synthesis component 24 emits the white light WL along the optical axis AX2. The optical axis AX2 of the white light WL is located on the same line as 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 synthesis component 24 in a manner that passes through the synthesis position of the colored light in the light synthesis component 24 and is further extended relative to the light synthesis component 24 to the side opposite to the second light source 20G.

[0072] The light synthesizing member 24 uses, for example, a cross dichroic prism 240. The cross dichroic prism 240 includes a first dichroic mirror 241 and a second dichroic mirror 242. When viewed from above or from the side with the optical axes AX1 and AX2 being perpendicular to each other, the reflection surface of the first dichroic mirror 241 and the reflection surface of the second dichroic mirror 242 are inclined relative to the optical axis AX1 and the optical axis AX2, respectively. When viewed from above or from the side, the reflection surface of the first dichroic mirror 241 and the reflection surface of the second dichroic mirror 242 each form an angle of 45° with the optical axes AX1 and AX2, respectively. When viewed from above or from the side with the optical axes AX1 and AX2 being perpendicular to each other, the reflection surface of the first dichroic mirror 241 and the reflection surface of the second dichroic mirror 242 are perpendicular to each other.

[0073] 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 is incident on the second dichroic mirror 242 along the optical axis AX1, is reflected by the second dichroic mirror 242, is emitted to the side opposite to the second light source 20G along the optical axis AX2, and is transmitted through the first dichroic mirror 241. The green light LG emitted from the second light source 20G is incident on the first dichroic mirror 241 along the optical axis AX2, goes straight, and is transmitted through the first dichroic mirror 241 and the second dichroic mirror 242. The blue light LB emitted from the third light source 20B is incident on the first dichroic mirror 241 along the optical axis AX1, is reflected by the first dichroic mirror 241, is emitted to the side opposite to the second light source 20G along the optical axis AX2, and is transmitted through the second dichroic mirror 242.

[0074] As described above, the red light RL, green light LG, and blue light LB emitted from the first dichroic mirror 241 and the second dichroic mirror 242 are combined to generate white light WL. The white light WL is emitted from the side surface of the cross dichroic prism 240 opposite to the side surface facing the second light source 20G along the optical axis AX2.

[0075] The focusing element 25 is arranged on the optical path of the white light WL between the photosynthetic component 24 and the diffusion device 40. The focusing element 25 focuses the white light WL emitted from the photosynthetic component 24 and in a parallelized state toward the diffusion device 40. The center of the focusing element 25 in a direction perpendicular to the optical axis AX2 roughly overlaps with the optical axis AX2. The focusing element 25 is, for example, a biconvex lens, but may also be an optical element having a focusing function other than a biconvex lens, may also be a plano-convex lens, or may be composed of a plurality of optical lenses.

[0076] The diffuser 40 is disposed on the optical path of the white light WL emitted from the condensing element 25. The diffuser 40 diffuses and emits the white light WL condensed and incident by the condensing element 25. The diffuser 40 is, for example, a reflective diffuser, and diffuses and reflects the incident white light WL.

[0077] The diffusion device 40 includes, for example, a substrate 41 and a driving device 42. The substrate 41 includes an incident surface 41a and a back surface 41b on the opposite side of the incident surface 41a. The incident surface 41a is irradiated with the white light WL focused by the focusing element 25 to form a focusing point SP of the white light WL. The substrate 41 is arranged so that the incident surface 41a faces the focusing element 25. When viewed from above or from the side with the optical axes AX1 and AX2 being orthogonal to each other, the angle between the incident surface 41a and the optical axis AX2 is 45°.

[0078] The substrate 41 is mounted on the driving device 42 in a state where 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 a shaft member 43 with the rotation axis OX1 as the axis. The shaft member 43 is inserted into the center of the substrate 41 from the back side 41b, for example. The centers of the incident surface 41a and the back side 41b of the substrate 41 overlap with the rotation axis OX1. The substrate 41 rotates around the rotation axis OX1 as described above, and the white light WL is diffused. In addition, the driving device 42 can be any device that can rotate the substrate 41 as described above, and is not limited to a motor.

[0079] Figure 3 4 is a schematic diagram of the substrate 41 of the diffusion device 40, and is a diagram of the substrate 41 viewed from the incident surface 41a side along the rotation axis OX1. Figure 2 and Figure 3 As shown, when observed along the rotation axis OX1, the focal point SP of the white light WL is formed in the area between the rotation axis OX1 and the peripheral end, which is the center in the radial direction of the center of 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. A concave-convex structure 47 is formed on the incident surface 41a. The concave-convex structure 47 is appropriately designed to appropriately diffuse the white light WL in consideration of the wavelength band of the white light WL, and is manufactured in the same manner as the concave-convex structure formed on a known diffusion plate. The concave-convex structure 47 can be formed, for example, by sandblasting, or by using photolithography technology to form a plurality of microlenses having a diameter less than the wavelength of the white light WL. The concave-convex structure 47 can also be formed, for example, by dispersing 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 in a manner reflecting the surface shape of the plurality of particles. In addition, the concave-convex structure 47 can also be formed as Figure 3 Although it is formed over the entire radial range from the center to the peripheral end of the incident surface 41a as shown, it may be formed over a range including at least a part of the region to be irradiated with the focal point SP in the radial direction.

[0080] When the substrate 41 is made of a material that is transmissive to the white light WL, such as optical glass or plastic, a reflective film (not shown) is provided on the surface of the concavo-convex structure 47. When the substrate 41 is made of a material that is reflective to the white light WL, such as metal, a reflective film (not shown) may not be provided on the surface of the concavo-convex structure 47, but by providing a reflective film, the reflection characteristics of the incident surface 41a are improved. Figure 3 In FIG. 4 , the concavo-convex structure 47 is exemplified by dots. The concavo-convex structure 47 is made of a material that transmits the white light WL and does not have a light shielding property, similarly to the substrate 41 .

[0081] The white light WL is diffused and reflected at the diffusion surface 45. In the diffused white light WL, the red light LR1 of the first wavelength band and the red light LR2 of the second wavelength band of the red light LR included in the white light WL, the green light LG1 of the first wavelength band and the green light LG2 of the second wavelength band of the green light LG included in the white light WL, and the blue light LB included in the white light WL are mixed with each other. In the plane intersecting the optical axes AX2 and AX10 of the focal point SP of the white light WL, the red light LR1, LR2, the green light LG1, LG2, and the blue light LB are distributed approximately uniformly. The substrate 41 of the diffusion device 40 rotates in the rotation direction DR with the rotation axis OX1 as the center, thereby changing the speckle pattern of the white light WL at the focal point SP.

[0082] The white light WL is diffused and reflected on the diffusion surface 45, and includes a diffusion, scattering or diffraction pattern caused by the concavo-convex structure 47, and is emitted as diffused light from the focal point SP along the optical axis AX10. The optical axis AX10 passes through the center of the irradiation area of ​​the focal point SP on the incident surface 41a of the substrate 41 and is parallel to the optical axis AX1.

[0083] The collimating element 26 is arranged on the optical path of the white light WL emitted from the substrate 41 of the diffusion device 40. The collimating element 26 parallelizes 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 orthogonal to the optical axis AX10 roughly overlaps with the optical axis AX10. The collimating element 26 is, for example, a biconvex lens, but it can also be an optical element with a focusing function other than a biconvex lens, it can also be a plano-convex lens, and it can also be composed of a plurality of optical lenses. In addition, in the case where the collimating element 26 is composed of one optical lens, the accuracy of parallelization can be further improved by using an aspheric lens.

[0084] The integrator optical system 50 includes a multi-lens array 51 and a superimposing lens 52. The integrator optical system 50 makes the illuminance distribution of the white light WL emitted from the collimator 26 uniform in the image forming regions of the light modulators 4R, 4G, and 4B disposed in the subsequent stages.

[0085] The multi-lens array 51 is arranged on the optical path of the white light WL emitted from the collimating element 26 and in a parallelized state. The multi-lens array 51 is, for example, a double-sided multi-lens array. The double-sided multi-lens array includes a plurality of microlenses 53 for dividing the white light WL emitted from the collimating element 26 into a plurality of small light beams. The plurality of microlenses 53 are adjacent to each other along a plane orthogonal to the optical axis AX10 and are arranged in a matrix. The microlenses 53 are, for example, plano-convex lenses convex to the incident side. The double-sided multi-lens array has a first multi-lens surface 51a arranged on the incident side along the shape of the plano-convex lenses constituting the microlenses 53. The double-sided multi-lens array includes a plurality of microlenses 54, the same number as the plurality of microlenses 53, on a plane perpendicular to the optical axis AX10. The individual microlenses 54 are adjacent to each other along a plane perpendicular to the optical axis AX10, are arranged in a matrix, and overlap with the individual microlenses 53. The microlenses 54 are, for example, plano-convex lenses convex to the emission side. The plane on the emission side of each of the plurality of microlenses 54 is the same as the plane on the incident side of each of the plurality of microlenses 53. The double-sided multi-lens array has a second multi-lens surface 51b provided on the emission side along the shape of the plano-convex lens constituting the microlenses 54.

[0086] The overlapping lens 52 converges the multiple small beams of white light WL emitted from the multi-lens array 51, and cooperates with the multiple micro lenses 54 of the multi-lens array 51 to make the multiple small beams overlap each other in the image forming area or near the image forming area of ​​each of the light modulating devices 4R, 4G, and 4B. The overlapping lens 52 is, for example, a plano-convex lens, but it can also be an optical element with a focusing function other than a plano-convex lens, it can also be a biconvex lens, and it can also be composed of multiple optical lenses.

[0087] The lighting device 2 of the first embodiment described above includes a first light source 20R, a second light source 20G, a photosynthetic component 24, a diffuser 40, a focusing element 25, and a collimating element 26. The first light source 20R emits red light (first light of a first color) LR. The second light source 20G emits green light (second light of a color different from the first light) LG. The photosynthetic component 24 combines the red light LR and the green light LG to emit white light (combined light) WL. The diffuser 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 focusing element 25 is arranged between the photosynthetic component 24 and the diffuser 40, and focuses the white light WL on the diffusion surface 45 of the substrate 41 of the diffuser 40. The collimating element 26 collimates the white light WL emitted from the substrate 41 of the diffuser 40. The first light source 20R includes 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 sink 211, and a second heat sink 212. Heat of the plurality of first laser elements 21R1 is transferred to the first heat sink 211. Heat of the plurality of second laser elements 21R2 is transferred to the second heat sink 212. The first laser element 21R1 emits red light LR1 of a first wavelength band. The second laser element 21R2 emits red light LR2 of a second wavelength band different from the first wavelength band. The heat dissipation capability of the first heat sink 211 and the heat dissipation capability of the second heat sink 212 are different from each other.

[0088] As for the lighting device 2 of the first embodiment, as a conventional lighting device, there is a structure in which the first light source 20R includes only the first laser element 21R1. In the lighting 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 lighting device 2 of the first embodiment, compared with the conventional lighting device that does not include the second laser element 21R2, a wavelength difference (λR12-λR11) is generated in the red light LR included in the white light WL diffused by the diffuser 40 and incident on the integrator optical system 50, and the speckle noise caused by the white light WL is 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 well reduced.

[0089] As conventional lighting devices different from the above-mentioned conventional lighting devices, there can be cited a structure in which the first light source 20R has a first laser element 21R1 and a second laser element 21R2 and does not have a first heat sink 211 and a second heat sink 212, and a structure in which the heat dissipation capacity of the first heat sink 211 and the heat dissipation capacity of the second heat sink 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 the reference operating temperature T0 due to heat dissipation by the first heat sink 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 by the second heat sink 212. Therefore, in the lighting device 2 of the first embodiment, by appropriately setting the heat dissipation capabilities of the first heat dissipating member 211 and the second heat dissipating member 212, the wavelength difference (λR2-λR1) of the red light LR included in the white light WL diffused by the diffuser 40 and incident on the integrator optical system 50 is larger than the wavelength difference (λR12-λR11), and the speckle noise caused by the white light WL is well 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 well and effectively reduced.

[0090] In a conventional lighting device without the first heat sink 211 and the second heat sink 212 and the heat sinks have the same heat dissipation capabilities, a countermeasure of preparing a first laser element 21R1 that emits red light LR1 having a red wavelength equivalent to wavelength λR1 at an operating temperature T0 as a single unit and a second laser element 21R2 that emits red light LR2 having a red wavelength equivalent to wavelength λR2 at an operating temperature T0 as a single unit is considered in order to increase the wavelength difference (λR12-λR11). However, in this countermeasure, in order to achieve a desired wavelength difference (λR2-λR1) in the red light LR, it is necessary to manufacture a plurality of types of first laser elements 21R1 and second laser elements 21R2, which results in a large number of manufacturing processes, work load, and cost compared to the case of adjusting the heat dissipation capabilities of the first heat sink 211 and the second heat sink 212. According to the lighting device 2 of the first embodiment, speckle noise generated in the white light WL emitted from the lighting device 2 and the projected image can be easily reduced at low cost. Furthermore, since the second laser element 21R2 that emits the red light LR2 having an excessively long wavelength need not be used, premature performance degradation of the second laser element 21R2 in the lighting device 2 can be prevented.

[0091] In the lighting device 2 of the first embodiment, the first wavelength band is shorter than the second wavelength band. The heat dissipation capability of the first heat dissipation member 211 is greater than the heat dissipation capability of the second heat dissipation member 212 .

[0092] In the illumination device 2 of the first embodiment, the first laser element 21R1 emits red light LR1 at an operating temperature T1 by heat dissipation of 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 by heat dissipation of the second heat dissipation member 212. As a result, the wavelength difference (λR2-λR1) in the red light LR included in the white light WL incident on the integrator optical system 50 is larger than the wavelength difference (λR12-λR11), and the speckle noise caused by the white light WL is well 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 well and effectively reduced.

[0093] In the lighting device 2 of the first embodiment, the first heat dissipation component 211 may include a heat sink (first heat sink) 121 having a plurality of first fins. The second heat dissipation component 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.

[0094] Although in Figure 2 Although omitted in the figure, in the lighting device 2 of the first embodiment, a plurality of first fins may be provided on the end faces and side faces other than the end face 121e of the heat sink 121 constituting the first heat dissipation component 211. The size and number of the first fins are set so that the heat sink 121 exhibits a heat dissipation capability of stabilizing the temperature of the first laser element 21R1 at the operating temperature T1 when emitting light by providing a plurality of first fins. Similarly, a plurality of second fins may be provided on the end faces and side faces other than the end face 122e of the heat sink 122 constituting the second heat dissipation component 212. The size and number of the second fins are set so that the heat sink 122 exhibits a heat dissipation capability of stabilizing the temperature of the second laser element 21R2 at the operating temperature T2 when emitting light by providing a plurality of second fins. In this structure, the heat dissipation capability 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 included in the white light WL incident on the integrator optical system 50 can be increased compared with the wavelength difference (λR12-λR11), thereby satisfactorily reducing speckle noise caused by the white light WL.

[0095] In the lighting device 2 of the first embodiment, the number of the plurality of first fins may be larger than the number of the plurality of second fins. In this structure, similar to the case where the size of the heat sink 121 is larger than the size of the heat sink 122, the heat dissipation capacity of the heat sink 121 is larger 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 included in the white light WL incident on the integrator optical system 50 can be enlarged compared to the wavelength difference (λR12-λR11), and the speckle noise caused by the white light WL can be reduced well.

[0096] Although in Figure 2 Although omitted in the figure, the first heat dissipation component 211 may also 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 component 212 may also include a heat sink 122 having a plurality of second fins. The heat sink 121 and the third heat sink may also be connected via a heat transfer component. As a heat transfer component, for example, a heat pipe may be cited.

[0097] In the lighting device 2 of the first embodiment, by thermally connecting the third heat sink to the heat sink 121 by means of the heat transfer member, the operating temperature T1 can be easily adjusted by using 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. In addition, the number of heat sinks and heat dissipation members other than the heat sink connected to at least one of the heat sink 121 constituting the first heat dissipation member 211 and the heat sink 122 constituting the second heat dissipation member 212 is not particularly limited and can be appropriately set according to the desired operating temperature T1.

[0098] In addition, the number of the first laser elements 21R1 and the number of the second laser elements 21R2 included in the first light source 20R is not limited to two, and is appropriately set in consideration of the light amount of the red light LR required by the lighting device 2, the light emission amount of the first laser element 21R1, and the light emission amount of the second laser element 21R2. 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 is not limited to two, and is appropriately set in consideration of the light amount of the green light LG required by the lighting device 2, the light emission amount of the first laser element 21G1, and the light emission amount of the second laser element 21G2. 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 required by the lighting device 2 and the light emission amount of the laser element 21B.

[0099] 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 reversed manner.

[0100] In the lighting device 2 according to the first embodiment, the first light is red.

[0101] The speckle noise caused by the red light LR among the three primary colors included in the white light WL is easily conspicuous. According to the illumination device 2 of the first embodiment, the wavelength difference (λR2-λR1) in the red light LR included in the white light WL incident on the integrator optical system 50 can be enlarged compared with the wavelength difference (λR12-λR11), thereby effectively reducing the speckle noise caused by the red light LR included in the white light WL.

[0102] As described above, in the lighting device 2 of the first embodiment, at the end face on the z-direction side of the two end faces of the heat sink 121, 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. In addition, in the lighting device 2 of the first embodiment, the number of the plurality of first laser elements 21R1 in the end face 121e of the heat sink 121 in the x-direction and the number in the y-direction may be changed and appropriately set. Similarly, the number of the plurality of second laser elements 21R2 in the x-direction and the number in the y-direction may be changed and appropriately set. In the lighting device 2 of the first embodiment, the number of the plurality of first laser elements 21G1 in the z-direction and the number in the y-direction may be changed and appropriately set. Similarly, the number of the plurality of second laser elements 21G2 in the z direction and the number in the y direction on the end surface 132 e of the heat sink 132 may be changed and appropriately set.

[0103] In addition, in the lighting device 2 of the first embodiment, it is considered that the blue light LB of the three primary colors included in the white light WL is sufficiently diffused by the diffusion device 40, and the speckle noise caused by the blue light LB is not easy to be noticeable. Therefore, the third light source 20B does not have a heat sink. On the other hand, the 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 easy to be noticeable. Therefore, the first light source 20R and the second light source 20G have heat sinks connected to each laser element as described above. However, even if the first heat sink 221 and the second heat sink 222 are not connected to the first laser element 21G1 and the second laser element 21G2, when the speckle noise caused by the green light LG is not noticeable, the first heat sink 221 and the second heat sink 222 may be omitted in the second light source 20G.

[0104] The projector 1 of the first embodiment includes the above-mentioned lighting device 2, light modulators 4R, 4G, 4B, and a projection optical system 6. The light modulator 4R modulates the red light RL included in the white light WL emitted from the lighting device 2 to generate red image light. The light modulator 4G modulates the green light GL included in the white light WL to generate green image light. The light modulator 4B modulates the blue light BL included in the white light WL to generate blue image light. The projection optical system 6 projects the image light modulated by the light modulators 4R, 4G, 4B.

[0105] 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 with the passage of 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 modulators 4R, 4G, 4B and the image light is projected onto the screen SCR, the speckle noise generated in the projected image can be well reduced.

[0106] (Second embodiment)

[0107] Next, refer to Figure 4 A lighting device 102 according to a second embodiment of the present invention will be described. In the description of the second embodiment, the same contents as those of the first embodiment will be omitted, and only the configuration and contents different from those described in the first embodiment will be described.

[0108] Although not shown in the drawings, the projector according to the second embodiment includes a lighting device 102 described below, instead of the lighting device 2 in the projector 1 according to the first embodiment.

[0109] Figure 4 1 is a schematic diagram showing the structure of the lighting device 102. The lighting 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 diffuser 40, a collimator 26, and an integrator optical system 50.

[0110] The first light source 20R includes 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 sink 211, a second heat sink 212, a third heat sink 213, a fourth heat sink 214, and a first collimating lens 22R, and emits red light LR. The third laser element 21R3 is equivalent to a third light emitting element. The fourth laser element 21R4 is equivalent to a fourth light emitting element. The red light LR includes a first wavelength band, a second wavelength band, a third wavelength band including at least a wavelength belonging to red in 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.

[0111] In the first light source 20R of the lighting device 102, on the end surface 121e of the heat sink 121, a first laser element 21R1 is arranged in the x direction, and two or more first laser elements 21R1 are arranged at intervals from each other in the y direction. On the end surface 122e of the heat sink 122, a second laser element 21R2 is arranged in the x direction, and two or more second laser elements 21R2 are arranged 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 the wavelength λR11 at the operating temperature T0. The size of each heat sink 121, 122 in the x direction is, for example, about 1 / 4 of the size of the photosynthesizing component 24 in the x direction.

[0112] The third laser element 21R3 corresponds to the third light emitting element. The third laser element 21R3 alone emits red light LR of wavelength λR13 at operating temperature T0. The wavelength λR13 is included in the third wavelength band of the red light LR. The wavelength λR13 is longer than the wavelength λR11, for example.

[0113] The third heat sink 213 is disposed on the opposite side of the x direction from the second heat sink 212 and in the z direction within a range overlapping with the first heat sink 211. The third heat sink 213 receives heat from the third laser element 21R3. In other words, the heat of the third laser element 21R3 is transferred to the third heat sink 213.

[0114] The third heat dissipation component 213 is, for example, a heat sink 123 formed of a rectangular parallelepiped, having two rectangular end faces parallel to each other and four side faces connecting the four sides of the two end faces to each other. 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 plane. On the end face 123e on the z-direction side of the two end faces of the heat sink 123, for example, one third laser element 21R3 is arranged in the x-direction, and two or more third laser elements 21R3 are arranged at intervals from each other in the y-direction. The end face 123e is a face of the heat sink 123 that faces the photosynthetic component 24.

[0115] The light emitting surface of the third laser element 21R3 is parallel to the xy plane and is the surface on the opposite side of 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) when emitting light. At least a part of the heat of the third laser element 21R3 is dissipated through 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 when emitting light. The sizes of the heat sink 123 in the x direction, the y direction, and the z direction are set so that the heat sink 123 exhibits a heat dissipation capability that stabilizes the temperature of the plurality of third laser elements 21R3 at the operating temperature T3 when emitting light.

[0116] The heat dissipation capacity of the heat sink 123 as the third heat dissipation component 213 is different from the heat dissipation capacity of each of the heat sinks 121 and 122. For example, the operating temperature T3 is higher than the operating temperature T1 and lower than the operating temperature T2, so (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 the same as the size of the heat sink 121 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.

[0117] The fourth laser element 21R4 is equivalent to the fourth light emitting element. The fourth laser element 21R4 alone emits red light LR with a wavelength of 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 of λR13 at the operating temperature T0.

[0118] The fourth heat sink 214 is disposed in the x direction at a position on the opposite side of the x direction from the second heat sink 212, and in the z direction within a range overlapping with the first heat sink 211. The fourth heat sink 214 receives heat from the fourth laser element 21R4. In other words, the heat of the fourth laser element 21R4 is transferred to the fourth heat sink 214.

[0119] The fourth heat dissipation component 214 is, for example, a heat sink 124 formed of a rectangular parallelepiped, having two rectangular end faces parallel to each other and four side faces connecting the four sides of the two end faces to each other. 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 plane. On the end face 124e on the z-direction side of the two end faces of the heat sink 124, for example, one fourth laser element 21R4 is arranged in the x-direction, and two or more fourth laser elements 21R4 are arranged at intervals from each other in the y-direction. The end face 124e is a face of the heat sink 124 that faces the photosynthetic component 24.

[0120] The light emitting surface of the fourth laser element 21R4 is parallel to the xy plane and is the surface on the opposite side of 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) when emitting light. At least a part of the heat of the fourth laser element 21R4 is dissipated through the adjacent heat sink 124. The fourth laser element 21R4 emits red light LR4 of wavelength λR4 at an operating temperature T4 higher than the operating temperature T2. The wavelength λR4 is included in the fourth wavelength band of the red light LR, is longer than the wavelengths λR1, λR2, and λR13, and is also 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 when emitting light. The sizes of the heat sink 124 in the x direction, the y direction, and the z direction are set so that the heat sink 124 exhibits a heat dissipation capability that stabilizes the temperature of the plurality of fourth laser elements 21R4 at the operating temperature T4 when emitting light.

[0121] The heat dissipation capacity of the heat sink 124 as the fourth heat dissipation component 214 is different from the heat dissipation capacity of the heat sink 123. For example, the operating temperature T4 is higher than the operating temperatures T1, T2, and T3, so (T4-T0)>(T2-T0)>(T3-T0)>(T1-T0). In this case, the heat dissipation capacity of the heat sink 124 is smaller than the heat dissipation capacity of the heat sink 122. Specifically, the size of the heat sink 124 in the x-direction and the y-direction is the same as the size of the heat sink 121 and 122 in the x-direction and the y-direction. 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.

[0122] The third laser element 21R3 emits red light LR3 radially from the light emitting surface with the z direction as the center. The fourth laser element 21R4 emits red light LR4 radially from the light emitting 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 638nm, and the wavelength λR13 of the third laser element 21R3 and the fourth laser element 21R4 at the operating temperature T0 is 642nm. The operating temperature T1 is 40°C, and the wavelength λR1 of the first laser element 21R1 at the operating temperature T1 is 639nm. The operating temperature T2 is 50°C, and the wavelength λR2 of the second laser element 21R2 at the operating temperature T2 is 641nm. The operating temperature T3 is 45°C, and the wavelength λR3 of the third laser element 21R3 at the operating temperature T3 is 644nm. 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.

[0123] In the above case, the wavelength difference (λR13-λR11) between the oscillation peak wavelength of the single first laser element 21R1 at the operating temperature T0 and the oscillation peak wavelength of the single fourth laser element 21R4 is 4 nm. The third laser element 21R3 is connected to the heat sink 123, and the fourth laser element 21R4 is connected to the heat sink 124. 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).

[0124] Furthermore, as the operation of the lighting 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 emitting two types of red light LR of wavelengths λR11 and λR13 at the operating temperature T0 to emitting four types of red light LR of wavelengths λR1, λR2, λR3, and λR4. That is, the types of wavelengths included in the red light LR increase from two types to four types.

[0125] The number of the first collimator 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 collimator lenses 22R are arranged on the optical path of the red light LR1 emitted from the first laser element 21R1, the optical path of the red light LR2 emitted from the second laser element 21R2, the optical path of the red light LR3 emitted from the third laser element 21R3, and the optical path of the red light LR4 emitted from the fourth laser element 21R4. The center of the first collimator lens 22R in the x direction substantially overlaps with any one of the center of the light emitting surface of the first laser element 21R1, 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 corresponding to the first collimator lens 22R.

[0126] 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.

[0127] The second light source 20G is disposed on the opposite side of the x direction from the first light source 20R. The second light source 20G includes a laser element 21G and a second collimator lens 22G, and emits green light LG.

[0128] The second light source 20G includes, 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 with the z direction as the center.

[0129] The number of the second collimating lenses 22G is the same as the total number of the laser elements 21G. The second collimating lenses 22G are arranged on the optical path of the green light LG emitted from each laser element 21G. The center of the second collimating 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 collimating lens 22G.

[0130] 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.

[0131] In addition, as described in the first embodiment, when the speckle noise caused by the green light LG becomes significant, the second light source 20G may be configured similarly to the first light source 20R, and include a laser element 21G that emits green light LG having wavelengths different from each other at an operating temperature T0, and a heat dissipation component that is connected to the laser element 21G and transfers the heat of the laser element 21G.

[0132] The lighting device 102 of the second embodiment includes a first light source 20R, a second light source 20G, a photosynthesizing member 24, a diffuser 40, a light focusing element 25, and a collimating element 26. According to the lighting device 102 of the second embodiment, similarly to the lighting device 2 of the first embodiment, when the white light WL emitted from the lighting device 102 is projected, speckle noise generated in the projected image can be well reduced.

[0133] In the lighting 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 sink 213, and a fourth heat sink 214. The third laser element 21R3 emits red light LR3 of a third wavelength band. The fourth laser element 21R4 emits red light LR4 of a fourth wavelength band different from the third wavelength band. Heat of the plurality of third laser elements 21R3 is transferred to the third heat sink 213. Heat of the plurality of fourth laser elements 21R4 is transferred to the fourth heat sink 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 sink 211 is greater than the heat dissipation capacity of the second heat sink 212, and greater than the heat dissipation capacity of the third heat sink 213. The heat dissipation capacity of the second heat dissipating member 212 is greater than that of the fourth heat dissipating member 214 and is less than that of the third heat dissipating member 213. The heat dissipation capacity of the third heat dissipating member 213 is greater than that of the fourth heat dissipating member 214.

[0134] In the lighting device 102 of the second embodiment, the first laser element 21R1 emits red light LR1 at an operating temperature T1 by heat dissipation of the first heat dissipation member 211. The second laser element 21R2 emits red light LR2 at an operating temperature T2 by heat dissipation of the second heat dissipation member 212. The third laser element 21R3 emits red light LR3 at an operating temperature T3 by heat dissipation of the third heat dissipation member 213. The fourth laser element 21R4 emits red light LR4 at an operating temperature T4 by heat dissipation of 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 diffuser 40 and incident on the integrator optical system 50 increases to 4, 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 well reduced. According to the lighting device 102 of the second embodiment, when the white light WL emitted from the lighting device 2 is projected, it is possible to effectively reduce speckle noise generated in the projected image.

[0135] Furthermore, in the lighting device 102 of the second embodiment, in addition to widening the wavelength difference of the red light LR 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, namely, the first wavelength band to the fourth wavelength band of the red light LR1, LR2, LR3, and LR4. Therefore, according to the lighting device 102 of the second embodiment, compared with the case where the wavelength of the red light LR is multiplexed into two wavelength bands, namely, the first wavelength band of the red light LR1 and the second wavelength band of the red light LR2 as in the lighting device 2 of the first embodiment, the wavelength band of the red light LR is widened, and the speckle noise of the white light WL can be well reduced.

[0136] In addition, in the first light source 20R of the lighting device 102 of the second embodiment, the arrangement of the first laser element 21R1 and the first heat sink 211, the second laser element 21R2 and the second heat sink 212, the third laser element 21R3 and the third heat sink 213, and the fourth laser element 21R4 and the fourth heat sink 214 in the x direction can also be freely changed. For example, the first laser element 21R1 and the first heat sink 211, the second laser element 21R2 and the second heat sink 212, the third laser element 21R3 and the third heat sink 213, and the fourth laser element 21R4 and the fourth heat sink 214 may be arranged in order along the x direction. In any arrangement, the same effects as those of the lighting device 102 of the second embodiment described above can be obtained.

[0137] Furthermore, in the lighting device 2 of the first embodiment, the number of the third laser elements 21R3 in the x direction and the number in the y direction on the end surface 123e of the heat sink 123 may be changed and appropriately set. Similarly, the number of the fourth laser elements 21R4 in the x direction and the number in the y direction on the end surface 124e of the heat sink 124 may be changed and appropriately set.

[0138] (Third embodiment)

[0139] Next, refer to Figures 5 to 8 A lighting device according to a third embodiment of the present invention will be described. In the description of the third embodiment, the same contents as those in the first and second embodiments will be omitted, and only the configurations and contents different from those described in the first and second embodiments will be described.

[0140] Figure 5 It is a perspective view showing the structure of a first light source 20R of the lighting device according to the third embodiment. Figure 6 1 is a top view of the first light source 20R of the lighting device of the 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 sink 211, a second heat sink 212, a third heat sink 213, and a first collimating lens 22R. Figure 5 as well as Figure 6 In FIG. 1 , the first collimating lens 22R is omitted.

[0141] In the third embodiment, the plurality of first laser elements 21R1 , the plurality of second laser elements 21R2 , and the plurality of third laser elements 21R3 are each configured as one package.

[0142] like Figure 5 as well as Figure 6 As shown, a plurality of first laser elements 21R1 are mounted on a plate surface 141f of a packaged base substrate 141 that is parallel to the yz plane. For example, five first laser elements 21R1 are arranged at intervals from each other 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 the end surface on the z direction side that is parallel to the xy plane.

[0143] The base substrate 141 is connected to the end surface 121 e of the heat sink 121 as the first heat dissipating member 211 . The heat of the five first laser elements 21R1 is transferred to the heat sink 121 via the base substrate 141 .

[0144] A plurality of second laser elements 21R2 are mounted on a plate surface 142f of a packaged base substrate 142 that is parallel to the yz plane. 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 on the z direction side that is parallel to the xy plane.

[0145] The base substrate 142 is connected to the end surface 122 e of the heat sink 122 as the second heat dissipating member 212 . The heat of the five second laser elements 21R2 is transferred to the heat sink 122 via the base substrate 142 .

[0146] A plurality of third laser elements 21R3 are mounted on a plate surface 143f parallel to the yz plane of the packaged 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 the end surface parallel to the xy plane on the z direction side.

[0147] The base substrate 143 is connected to the end surface 123 e of the heat sink 123 as the third heat dissipating member 213 . The heat of the five third laser elements 21R3 is transferred to the heat sink 123 via the base substrate 143 .

[0148] like Figure 6 As shown, the widths WTH1 of the heat sinks 121, 122, and 123 in the x direction are the same. The length LTH2 of the heat sink 122 in the z direction is shorter than the length LTH1 of the heat sink 121 in the z direction. The length LTH3 of the heat sink 123 in the z direction is shorter than the length LTH2 of the heat sink 122 in the z direction. The heights of the heat sinks 121, 122, and 123 in the y direction are the same. The lengths of the base substrates 141, 142, and 143 in the z direction are appropriately adjusted, for example, according to the relative positions of the end surfaces 121e, 122e, and 123e of the heat sinks 121, 122, and 123 so that the light emitting surfaces of the first laser element 21R1, the second laser element 21R2, and the third laser element 21R3 are arranged at the same positions in the z direction.

[0149] Figure 7 It is a perspective view showing the structure of a modified example of the first light source 20R of the lighting device according to the third embodiment. Figure 8 FIG. 2 is a top view of a modified example of the first light source 20R of the lighting device of the third embodiment. Figure 7and Figure 8 As shown, the width WTH2 of the heat sink 122 in the x direction may be shorter than the width WTH1 of the heat sink 121 in the x direction. The width WTH3 of the heat sink 123 in the x direction may be shorter than the width WTH2 of the heat sink 122 in the x direction. The lengths LTH1, LTH2, and LTH3 of the heat sinks 121, 122, and 123 in the z direction are the same.

[0150] In the lighting device of the third embodiment, the plurality of first laser elements (first light emitting elements) 21R1 are arranged one-dimensionally along the y direction. The plurality of second laser elements (second light emitting elements) 21R2 are arranged one-dimensionally along the y direction. The plurality of first laser elements 21R1 and the plurality of second laser elements 21R2 are separate from each other. The plurality of first laser elements 21R1 are one package. The plurality of second laser elements 21R2 are one package.

[0151] In the lighting device of the third embodiment, the plurality of first laser elements 21R1 are packaged, and the plurality of second laser elements 21R2 are packaged separately from the plurality of first laser elements 21R1. Therefore, the first light source 20R can be easily combined with the first heat sink 211 and the second heat sink 212.

[0152] In the first light source 20R of the lighting device of the third embodiment, the number of the first collimating lenses 22R is the same as the total number of the plurality of first laser elements 21R1, the plurality of second laser elements 21R2, and the plurality of third laser elements 21R3. The plurality of first collimating lenses 22R may be separately arranged on the z-direction side of the light emitting surface of each laser element from the packages of the plurality of first laser elements 21R1, the packages of the plurality of second laser elements 21R2, and the packages of the plurality of third laser elements 21R3, or may be mounted in the packages of each laser element.

[0153] In the first light source 20R of the lighting device of the third embodiment, the case where the paths of the red light LR1 emitted from the plurality of first laser elements 21R1, the red light LR2 emitted from the plurality of second laser elements 21R2, and the red light LR3 emitted from the plurality of third laser elements 21R3 are adjusted in the x direction, the y direction, and the z direction, respectively, is considered. In this case, an optical element such as a reflector that bends the red light LR may be appropriately arranged between the light emitting surface of the plurality of first laser elements 21R1, the light emitting surface of the plurality of second laser elements 21R2, and the light emitting surface of the plurality of third laser elements 21R3, which emits the red light LR whose path is to be adjusted, and the incident surface of the red light LR in the light combining unit 24.

[0154] As mentioned above, although the preferred embodiment of the present invention is described in detail, the present invention is not limited to this specific embodiment, and various modifications and changes can be made within the scope of the gist of the present invention described in the claims.

[0155] For example, the shape, number, arrangement, and material of each component of the lighting device and the projector are not limited to those described in the above-mentioned embodiment and modified examples, and may be modified as appropriate.

[0156] In the above-mentioned embodiment, as the lighting device of the present invention, a reflective diffuser is shown as an example of a diffuser, but the present invention is not limited to this example. For example, the lighting device of the present invention may also have a transmissive diffuser as a diffuser. In this case, a reflective film is not provided on the substrate of the diffuser. The synthetic light diffused by the diffusion surface of the substrate of the diffuser and transmitted through the substrate is emitted from the emission surface of the substrate along an optical axis that is in a straight line with the optical axis of the synthetic light incident on the substrate. In addition, in the above-mentioned embodiment, the diffuser is a reflective diffuser, and therefore, compared with the case of a transmissive diffuser, the polarization disorder of the synthetic light emitted from the diffuser is less.

[0157] In the above-mentioned embodiment, an example of the lighting device of the present invention being mounted on a projector using a liquid crystal panel is shown, but the present invention is not limited to this example. For example, the lighting device of the present invention can also be applied to a projector using a digital micromirror device as a light modulator. The projector of the present invention may not have a plurality of light modulators, but may be a single-panel projector having only one light modulator.

[0158] [Summary of the present disclosure]

[0159] The following is a summary of the present disclosure.

[0160] (Supplementary Note 1) A lighting device, comprising: a first light source that emits a first light of a first color; a second light source that emits a second light of a color different from that of the first light; a photosynthetic component that synthesizes the first light and the second light to emit synthesized light; a diffusion device having a substrate and a driving device, the substrate having a diffusion surface that diffuses and emits the incident synthesized light, and the driving device rotates the substrate; a focusing element that is arranged between the photosynthetic component and the diffusion device and focuses the synthesized light on the diffusion surface of the diffusion device; and a collimating element that parallelizes the synthesized light emitted from the diffusion device. The first light source comprises: 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 component to which heat from the plurality of first light-emitting elements is transferred; and a second heat dissipation component to which heat from the plurality of second light-emitting elements is transferred, and the heat dissipation capacity of the first heat dissipation component and the heat dissipation capacity of the second heat dissipation component are different from each other.

[0161] According to the structure 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 sink and the second heat sink, and compared with the conventional lighting device, the synthesized light with reduced speckle noise can be incident on the diffusion device and the subsequent optical system. Therefore, according to the structure of Supplementary Note 1, when the synthesized light emitted from the lighting device is projected, the speckle noise generated in the projected image can be well reduced.

[0162] (Supplementary Note 2) The lighting device according to 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 component is greater than the heat dissipation capacity of the second heat dissipation component.

[0163] According to the structure 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 in 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 light spot of the synthetic light formed on the diffusion surface of the diffusion device can be changed with the passage of time.

[0164] (Supplementary Note 3) The lighting device according to Supplementary Note 2, wherein the first heat dissipation component includes a first heat sink having a plurality of first fins, the second heat dissipation component includes a second heat sink having a plurality of second fins, and the size of the first heat sink is larger than the size of the second heat sink.

[0165] According to 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.

[0166] (Note 4) The lighting device according to Note 2 or 3, wherein the first heat dissipation component includes a first heat sink having a plurality of first fins, and the second heat dissipation component 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.

[0167] According to 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.

[0168] (Note 5) A lighting device according to any one of Notes 1 to 4, wherein the first heat dissipation component 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 component includes a second heat sink having a plurality of second fins, and the first heat sink and the third heat sink are connected via a heat transfer component.

[0169] According to the structure of Note 5, the third heat sink can be thermally connected to the first heat sink to adjust the wavelength of the first light emitted from the first light emitting element, 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 expanded through the first heat dissipation component and the second heat dissipation component.

[0170] (Note 6) An illumination device according to any one of Notes 1 to 5, wherein the plurality of first light-emitting elements are arranged in parallel in one dimension, the plurality of second light-emitting elements are arranged in parallel in one dimension, 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 a package, and the plurality of second light-emitting elements are a package.

[0171] According to the structure of Supplementary Note 6, the first heat dissipation component can be easily connected to the packaged first light emitting element, and the wavelength of the first light emitted from the first light emitting element can be set and adjusted. The second heat dissipation component can be easily connected to the packaged second light emitting element, and the wavelength of the second light emitted from the second light emitting element can be set and adjusted.

[0172] (Supplementary Note 7) According to the lighting device described in any one of Supplementary Notes 1 to 6, the first light source also has: 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 component to which heat of the plurality of third light-emitting elements is transferred; and a fourth heat dissipation component to which heat of the plurality of fourth light-emitting elements is transferred, the first wavelength band is shorter than the second wavelength band, 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 component is greater than the heat dissipation capacity of the second heat dissipation component and greater than the heat dissipation capacity of the third heat dissipation component, the heat dissipation capacity of the second heat dissipation component is greater than the heat dissipation capacity of the fourth heat dissipation component and is less than the heat dissipation capacity of the third heat dissipation component, and the heat dissipation capacity of the third heat dissipation component is greater than the heat dissipation capacity of the fourth heat dissipation component.

[0173] According to the structure of Supplementary Note 7, the first light of four wavelength bands is generated, 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 enlarged by the first heat sink and the fourth heat sink, so that the synthesized light with reduced speckle noise can be incident on the diffusion device and the subsequent optical system compared with the conventional illumination device. Therefore, according to the structure of Supplementary Note 7, when the synthesized light emitted from the illumination device is projected, the speckle noise generated in the projected image can be well reduced.

[0174] (Supplementary Note 8) The lighting device according to any one of Supplementary Notes 1 to 7, wherein the first color is red.

[0175] Among the three primary colors, speckle noise caused by red light is most noticeable. According to the structure of Supplementary Note 8, the synthesized light with effectively reduced speckle noise can be incident on the diffusion device and the subsequent optical system. Therefore, according to the structure of Supplementary Note 8, when the synthesized light emitted from the illumination device is projected, the speckle noise generated in the projected image can be well reduced.

[0176] (Supplement 9) A projector comprising: an illumination device according to any one of Supplements 1 to 8; a light modulating device for modulating light emitted from the illumination device; and a projection optical system for projecting light modulated by the light modulating device.

[0177] According to the configuration of Supplementary Note 9, when the synthesized light emitted from the illumination device is converted into image light by the light modulation device and the image light is projected, speckle noise generated in the projected image can be reduced favorably.

Claims

1. A lighting device comprising: a first light source emitting 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 for combining the first light and the second light to emit combined light; a diffusion device having a substrate and a driving device, wherein the substrate has a diffusion surface that diffuses the incident synthetic light and emits it, and the driving device rotates the substrate; A light-concentrating element is disposed between the light-combining component and the diffusion device, and converges the synthesized light onto the diffusion surface of the diffusion device; and a collimating element which collimates the synthetic light emitted from the diffusing device, The first light source comprises: 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 of the plurality of first light emitting elements is transferred; as well as a second heat dissipation member to which the heat of the plurality of second light emitting elements is transferred, The heat dissipation capability of the first heat dissipation member and the heat dissipation capability of the second heat dissipation member are different from each other.

2. The lighting device according to claim 1, wherein: The first waveband is shorter than the second waveband, The heat dissipation capacity of the first heat dissipation member is greater than the heat dissipation capacity of the second heat dissipation member.

3. The lighting device according to claim 2, wherein: The first heat dissipation component includes a first heat sink having a plurality of first fins. The second heat dissipation component includes a second heat sink having a plurality of second fins. The size of the first heat sink is larger than that of the second heat sink.

4. The lighting device according to claim 2, wherein: The first heat dissipation component includes a first heat sink having a plurality of first fins. The second heat dissipation component includes a second heat sink having a plurality of second fins. The number of the plurality of first fins is greater than the number of the plurality of second fins.

5. The lighting device according to claim 2, wherein: The first heat dissipation component 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 component includes a second heat sink having a plurality of second fins. The first heat sink and the third heat sink are connected via a heat transfer member.

6. The lighting device according to any one of claims 1 to 5, wherein: The plurality of first light emitting elements are arranged in parallel in one dimension, The plurality of second light emitting elements are arranged in parallel in one dimension, 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 a package, The plurality of second light emitting elements form one package.

7. The lighting device according to any one of claims 1 to 5, wherein: The first light source further comprises: A plurality of third light emitting elements, which emit the first light in a third wavelength band; a plurality of fourth light emitting elements emitting 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 the heat of the plurality of fourth light emitting elements is transferred, The first waveband is shorter than the second waveband, The third band is shorter than the fourth band, The first band and the second band are shorter than the third band and the fourth band, The heat dissipation capacity of the first heat dissipation component is greater than the heat dissipation capacity of the second heat dissipation component, and greater than the heat dissipation capacity of the third heat dissipation component. The heat dissipation capacity of the second heat dissipation component is greater than the heat dissipation capacity of the fourth heat dissipation component and is less than the heat dissipation capacity of the third heat dissipation component. The heat dissipation capacity of the third heat dissipation member is greater than the heat dissipation capacity of the fourth heat dissipation member.

8. The lighting device according to any one of claims 1 to 5, wherein: The first color is red.

9. A projector comprising: The lighting device according to any one of claims 1 to 5; a light modulation device for modulating light emitted from the illumination device; and A projection optical system projects the light modulated by the light modulation device.

Images