Luminaire and projector

Abstract

To provide a highly efficient luminaire and a projector.SOLUTION: The luminaire comprises: a first laser light source part emitting first light in a first wavelength range; a second laser light source part emitting second light in a second wavelength range; a first diffusion member; a second diffusion member; and a photosynthetic element combining the first light and the second light. The first diffusion member includes a first dielectric multilayer film reflecting the first light while the second diffusion member includes a second dielectric multilayer film reflecting the second light. A first incident angle denotes incident angle of a principal ray of the first light entering the first diffusion member while a second incident angle denotes incident angle of a principal ray of the second light entering the second diffusion member. The first dielectric multilayer film has a characteristic such that reflectance ratio of light incident at the first incident angle in the first wavelength range is higher than reflectance ratio of light incident at the first incident angle in the second wavelength range. On the other hand, the second dielectric multilayer film has a characteristic such that reflectance ratio of light incident at the second incident angle in the second wavelength range is higher than reflectance ratio of light incident at the second incident angle in the first wavelength range.SELECTED DRAWING: Figure 2

Description

[Technical field]

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

[0002] In order to improve the performance of projectors, projectors equipped with illumination devices using laser light sources, which are light sources with a wide color gamut and high efficiency, have been proposed. The following Patent Document 1 discloses a light-emitting module equipped with a blue laser light source, a green laser light source, a red laser light source, a light-combining optical system that combines the light emitted from these three color laser light sources, and a diffusion wheel that diffuses the incident light. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2023-523358 Summary of the Invention [Problem to be solved by the invention]

[0004] In the light-emitting module of Patent Document 1, blue light, green light, and red light emitted from three laser light sources are combined by a light-combining optical system, and the combined light is diffused and reflected by a diffusion wheel. At this time, the diffusion wheel is rotated by a motor to reduce speckles specific to laser light. A dielectric multilayer film with excellent reflectance is often used for this type of reflective diffusion wheel. However, in this configuration, since white light including blue light, green light, and red light is incident on the diffusion wheel, it is difficult to form a dielectric multilayer film with good reflectance over a wide wavelength band from the blue wavelength band to the red wavelength band, and there is a problem that a highly efficient lighting device cannot be obtained. [Means for solving the problem]

[0005] In order to solve the above problems, an illumination device according to one embodiment of the present invention includes a first laser light source unit that emits a first light in a first wavelength band, a second laser light source unit that emits a second light in a second wavelength band different from the first wavelength band, a first diffusing member that diffuses and reflects the first light emitted from the first laser light source unit, a second diffusing member that diffuses and reflects the second light emitted from the second laser light source unit, and a light combining element that combines the first light emitted from the first diffusing member and the second light emitted from the second diffusing member and emits a combined light. The first diffusing member has a first dielectric multilayer film that reflects the first light. The second diffusing member has a second dielectric multilayer film that reflects the second light. When the angle of incidence of the chief ray of the first light incident on the first diffusing member is defined as a first angle of incidence and the angle of incidence of the chief ray of the second light incident on the second diffusing member is defined as a second angle of incidence, the first dielectric multilayer film has a characteristic in which the reflectance in the first wavelength band of light incident at the first angle of incidence is higher than the reflectance in the second wavelength band of light incident at the first angle of incidence, and the second dielectric multilayer film has a characteristic in which the reflectance in the second wavelength band of light incident at the second angle of incidence is higher than the reflectance in the first wavelength band of light incident at the second angle of incidence.

[0006] A projector of one embodiment of the present invention comprises an illumination device of one embodiment of the present invention, an optical modulation device that modulates light including the composite light emitted from the illumination device in accordance with image information, and a projection optical device that projects the light modulated by the optical modulation device. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic configuration diagram of a projector according to a first embodiment. [Diagram 2] 1 is a schematic configuration diagram of a lighting device according to a first embodiment. [Diagram 3] FIG. [Figure 4] 4 is a cross-sectional view of the diffusion plate taken along line IV-IV in FIG. 3. [Diagram 5] FIG. 2 is a diagram showing an example of the spectral characteristics of a dielectric multilayer film. [Figure 6] FIG. 11 is a schematic configuration diagram of an illumination device according to a second embodiment. [Figure 7] FIG. 13 is a diagram showing an example of a light intensity distribution curve after diffusion. [Figure 8] FIG. 11 is a schematic configuration diagram of an illumination device according to a third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] [First embodiment] Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. The projector of this embodiment is an example of a liquid crystal projector equipped with an illumination device using a laser diode. In the drawings, the dimensions of the components may be shown on different scales in order to make the components easier to see.

[0009] The projector 10 of this embodiment is a projection-type image display device that displays a color image on a screen (projection surface) SCR. The projector 10 includes three light modulation devices corresponding to red light LR, green light LG, and blue light LB. The projector 10 includes a laser diode that can obtain high-luminance and high-output light as a light-emitting element of the light source device.

[0010] FIG. 1 is a schematic configuration diagram of a projector 10 according to the present embodiment. 1, the projector 10 includes an illumination device 700, a color separation light guide optical system 200, a red light optical modulation device 400R, a green light optical modulation device 400G, a blue light optical modulation device 400B, a combining optical system 500, and a projection optical device 600. The red light optical modulation device 400R, the green light optical modulation device 400G, and the blue light optical modulation device 400B form image light by modulating light including combined light LW emitted from the illumination device 700 according to image information. The projection optical device 600 projects the image light onto a screen SCR (projection surface).

[0011] FIG. 2 is a schematic diagram of the illumination device 700. As shown in FIG. As shown in FIG. 2, the illumination device 700 includes a blue light source unit 20, a green light source unit 30, a red light source unit 40, a light combining element 50, a double-sided multi-lens array 60, a displacement device 70, and a superimposing lens 80.

[0012] In the following description, the axis along the direction in which light is emitted from the blue light source unit 20 and the red light source unit 40 is the X axis, the axis along the direction in which the combined light LW is emitted from the lighting device 700 is the Y axis, and the axis perpendicular to the X axis and the Y axis is the Z axis. In addition, the optical axis of the first condenser lens 23 (the central axis of the blue light LB emitted from the blue laser diode array 21) is the optical axis AX1, the optical axis of the second condenser lens 33 (the central axis of the green light LG emitted from the green laser diode array 31) is the AX2, the optical axis of the third condenser lens 43 (the central axis of the red light LR emitted from the red laser diode array 41) is the AX3, the optical axis of the first collimator lens 25 and the third collimator lens 45 passing through the center of the light combining element 50 is the AX4, and the optical axis of the second collimator lens 35 passing through the center of the light combining element 50 is the AX5.

[0013] The blue light source section 20 includes a blue laser diode array 21 , a first collimator lens array 22 , a first condenser lens 23 , a first diffusion device 24 , and a first collimator lens 25 .

[0014] The blue laser diode array 21 has a plurality of blue laser diodes 211 arranged in an array. The blue laser diode 211 emits a blue beam LB0 of a first wavelength band in the -Y direction. The first wavelength band is, for example, 455 nm±10 nm. The number and arrangement of the blue laser diodes 211 are not particularly limited. The blue laser diode array 21 of this embodiment corresponds to a first laser light source unit in the claims.

[0015] The first collimator lens array 22 is provided on the light emission side of the blue laser diode array 21. The first collimator lens array 22 has a plurality of collimator lenses 221 provided corresponding to the plurality of blue laser diodes 211, respectively. The collimator lenses 221 are composed of convex lenses. The collimator lenses 221 collimate the blue beams LB0 emitted from the blue laser diodes 211. Hereinafter, the plurality of blue beams LB0 emitted from the first collimator lens array 22 will be collectively referred to as blue light LB. The blue light LB in this embodiment corresponds to the first light in the claims.

[0016] The first collecting lens 23 is provided on the light emission side of the first collimator lens array 22. The first collecting lens 23 is composed of a convex lens. The first collecting lens 23 collects the blue light LB emitted from the first collimator lens array 22 and emits it toward the first diffusion plate 241. According to this configuration, since the blue light LB collected by the first collecting lens 23 is incident on the first diffusion plate 241, it is not necessary to make the first diffusion plate 241 unnecessarily large, and the illumination device 700 can be made more compact.

[0017] The first diffusion device 24 has a disk-shaped first diffusion plate 241 and a driving device 242. The first diffusion plate 241 has a diffusion surface 241a that diffuses and reflects the blue light LB emitted from the first condenser lens 23. That is, the first diffusion plate 241 of this embodiment is a reflective diffusion plate, not a transmissive diffusion plate. The diffusion surface of the first diffusion plate 241 is disposed at the focal position of the first condenser lens 23. The driving device 242 is composed of a motor, and rotates the first diffusion plate 241 about a rotation axis C1 that intersects with the diffusion surface 241a. Note that the diffusion surface 241a in this specification does not mean a curved surface having a fine uneven structure shape described later, but means a plane on which a plurality of concaves and a plurality of convexities are generally arranged. The first diffusion plate 241 of this embodiment corresponds to the first diffusion member of the claims.

[0018] The first diffusion plate 241 is disposed such that the diffusion surface 241a is inclined at 45° with respect to each of the optical axis AX1 and the optical axis AX4. That is, the diffusion surface 241a is inclined at 45° with respect to the optical axis AX1 of the first condenser lens 23. Therefore, the chief ray of the blue light LB emitted from the first condenser lens 23 is incident on the diffusion surface 241a at an incident angle of 45°. With this configuration, the traveling direction of the chief ray of the blue light LB incident on the diffusion surface 241a can be made substantially perpendicular to the traveling direction of the chief ray of the blue light LB emitted from the diffusion surface 241a. This makes it possible to facilitate the design of the illumination device 700.

[0019] Fig. 3 is a front view of the first diffusion device 24. Fig. 4 is a cross-sectional view of the first diffusion plate 241 taken along the line IV-IV in Fig. 3. The configuration of the first diffusion plate 241 is similar to that of the second diffusion plate 341 and the third diffusion plate 441, except for the specifications of the dielectric multilayer film. Therefore, in the following, the first diffusion plate 241 will be representatively described in detail, and detailed descriptions of the second diffusion plate 341 and the third diffusion plate 441 will be omitted.

[0020] 3 and 4, the first diffusion plate 241 has a light-transmitting substrate 243, a metal reflective film 244, and a dielectric multilayer film 247. The dielectric multilayer film 247 corresponds to the first dielectric multilayer film in the claims. The metal reflective film 244 corresponds to the metal film in the claims.

[0021] The light-transmitting substrate 243 is made of optical glass such as BK7. Of the two surfaces of the light-transmitting substrate 243, the diffusion surface 241a on which the blue light LB is incident is provided with an uneven structure 246 consisting of a plurality of recesses and a plurality of protrusions. The uneven structure 246 includes a plurality of curved surfaces arranged randomly. That is, the light-transmitting substrate 243 has the uneven structure 246 including a plurality of recesses and a plurality of protrusions. Each recess is formed in a substantially spherical shape. The depth of the recess is, for example, about 1 / 4 of the diameter of the sphere. The uneven structure 246 can be formed by a method such as cutting the light-transmitting substrate 243 by etching or the like, or plastically deforming the substrate by blasting or the like.

[0022] The metal reflective film 244 is provided along the uneven structure 246 of the light-transmitting substrate 243. The metal reflective film 244 is made of a material containing aluminum, for example. Specifically, the metal reflective film 244 is made of high-purity aluminum with an aluminum content of 99.99 wt% or more. Preferably, the metal reflective film 244 can be made of ultra-high-purity aluminum with an aluminum content of 99.999 wt% or more.

[0023] The metallic reflective film 244 is obtained by forming a pure aluminum film having a smooth surface and a predetermined film thickness using a film formation method such as sputtering or vapor deposition on the diffusion surface 241a of the light-transmitting substrate 243. When a sputtering target having an aluminum content of, for example, 99.999 wt% is used in the film formation process, the metallic reflective film 244 made of ultra-high purity aluminum having an aluminum content of 99.999 wt% is obtained.

[0024] The dielectric multilayer film 247 is provided on the surface of the metal reflective film 244 opposite to the light-transmitting substrate 243. That is, the first diffusion plate 241 has a configuration in which the metal reflective film 244 and the dielectric multilayer film 247 are laminated in this order on the light-transmitting substrate 243. Although not shown in Fig. 4, the dielectric multilayer film 247 has a configuration in which two types of dielectric films having different refractive indices are alternately laminated multiple times.

[0025] In the first diffusion plate 241 of the present embodiment, the uneven structure 246 reflects the blue light LB emitted from the first condenser lens 23 once and emits it toward the first collimator lens 25. Therefore, the blue light LB emitted from the first condenser lens 23 is emitted from the first diffusion plate 241 toward the first collimator lens 25 without multiple reflections on the diffusion surface 241a. With this configuration, since the blue light LB emitted from the first condenser lens 23 is not multiple reflected on the diffusion surface 241a, it is possible to suppress disturbance of the polarization direction of the blue light LB. The first diffusion plate 241 may be a microlens array type diffusion plate provided with a microlens array.

[0026] 4, the first diffuser 241 may not be provided with a metal reflective film, and the dielectric multilayer film may be formed directly on the uneven structure of the light-transmitting substrate. This configuration can simplify the manufacturing process of the first diffuser. However, if a metal reflective film is provided, the metal reflective film and the dielectric multilayer film together perform the reflective function, so that the number of layers in the dielectric multilayer film can be reduced.

[0027] Alternatively, the first diffusion plate may be composed of a metal substrate and a dielectric multilayer film. For example, an aluminum alloy may be used as the metal substrate. For example, an Al-Mg-Si alloy in which magnesium (Mg) and silicon (Si) are added to aluminum (Al) may be used as the aluminum alloy. In addition, the aluminum alloy may contain elements such as iron (Fe), copper (Cu), manganese (Mn), chromium (Cr), zinc (Zn), and titanium (Ti). In this case, a concave-convex structure may be formed on one surface of the metal substrate by subjecting the metal substrate to a blasting process, and the dielectric multilayer film may be formed on the concave-convex structure. This configuration can simplify the configuration of the first diffusion plate.

[0028] 2, the first collimator lens 25 is provided on the light exit side of the first diffusion plate 241 on the optical axis AX4. The first collimator lens 25 is composed of a convex lens. The first collimator lens 25 collimates the blue light LB exiting from the first diffusion plate 241 at a predetermined diffusion angle, and outputs the parallel light toward the light combining element 50.

[0029] Green light source section 30 includes green laser diode array 31, second collimator lens array 32, second condenser lens 33, second diffusion device 34, and second collimator lens 35. Note that the basic configuration of each component of green light source section 30 is common to each component of blue light source section 20, and therefore a description of the common parts will be omitted.

[0030] The green laser diode array 31 has a plurality of green laser diodes 311 arranged in an array. The green laser diode 311 emits a green beam LG0 of a second wavelength band in the +X direction. The second wavelength band is, for example, 535 nm±10 nm. The number and arrangement of the green laser diodes 311 are not particularly limited. The green laser diode array 31 of this embodiment corresponds to the second laser light source unit in the claims.

[0031] The second collimator lens array 32 is provided on the light emission side of the green laser diode array 31. The second collimator lens array 32 has a plurality of collimator lenses 321 provided corresponding to the plurality of green laser diodes 311, respectively. The collimator lenses 321 are formed of convex lenses. The collimator lenses 321 collimate the green beams LG0 emitted from the green laser diodes 311. Hereinafter, the plurality of green beams LG0 emitted from the second collimator lens array 32 will be collectively referred to as green light LG. The green light LG in this embodiment corresponds to the second light in the claims.

[0032] The second condenser lens 33 is provided on the light exit side of the second collimator lens array 32. The second condenser lens 33 is composed of a convex lens. The second condenser lens 33 collects the green light LG exiting from the second collimator lens array 32, and emits the collected light toward the second diffuser plate 341.

[0033] The second diffusion device 34 has a disk-shaped second diffusion plate 341 and a driving device 342. The second diffusion plate 341 has a diffusion surface 341a that diffuses and reflects the green light LG emitted from the second condenser lens 33. The diffusion surface 341a of the second diffusion plate 341 is disposed at the focal position of the second condenser lens 33. The configuration of the driving device 342 is similar to that of the driving device 242 of the blue light source unit 20. The driving device 342 rotates the second diffusion plate 341 around a rotation axis C2.

[0034] The second diffusing plate 341 is disposed such that the diffusing surface 341a is inclined at 45° with respect to each of the optical axis AX2 and the optical axis AX5. That is, the diffusing surface 341a is inclined at 45° with respect to the optical axis AX2 of the second condenser lens 33. Therefore, the chief ray of the green light LG emitted from the second condenser lens 33 is incident on the diffusing surface 341a at an incident angle of 45°.

[0035] The second collimator lens 35 is provided on the light exit side of the second diffuser plate 341 on the optical axis AX5. The second collimator lens 35 is composed of a convex lens. The second collimator lens 35 collimates the green light LG exiting from the second diffuser plate 341 at a predetermined diffusion angle, and outputs the parallel light toward the light combining element 50.

[0036] Red light source section 40 includes red laser diode array 41, third collimator lens array 42, third condenser lens 43, third diffusion device 44, and third collimator lens 45. Note that the basic configuration of each component of red light source section 40 is common to each component of blue light source section 20, and therefore a description of the common parts will be omitted.

[0037] The red laser diode array 41 has a plurality of red laser diodes 411 arranged in an array. The red laser diode 411 emits a red beam LR0 of a third wavelength band in the +Y direction. The third wavelength band is, for example, 640 nm±10 nm. The number and arrangement of the red laser diodes 411 are not particularly limited. The red laser diode array 41 of this embodiment corresponds to a third laser light source unit in the claims.

[0038] The third collimator lens array 42 is provided on the light emission side of the red laser diode array 41. The third collimator lens array 42 has a plurality of collimator lenses 421 provided corresponding to the plurality of red laser diodes 411, respectively. The collimator lenses 421 are formed of convex lenses. The collimator lenses 421 collimate the red beam LR0 emitted from the red laser diode 411. Hereinafter, the plurality of red beams LR0 emitted from the third collimator lens array 42 will be collectively referred to as red light LR. The red light LR in this embodiment corresponds to the third light in the claims.

[0039] The third condenser lens 43 is provided on the light exit side of the third collimator lens array 42. The third condenser lens 43 is composed of a convex lens. The third condenser lens 43 collects the red light LR exiting from the third collimator lens array 42, and emits the collected light toward the third diffuser plate 441.

[0040] The third diffusion device 44 has a disk-shaped third diffusion plate 441 and a driving device 442. The third diffusion plate 441 has a diffusion surface 441a that diffusely reflects the red light LR emitted from the third condenser lens 43. The diffusion surface 441a of the third diffusion plate 441 is disposed at the focal position of the third condenser lens 43. The configuration of the driving device 442 is similar to that of the driving device 242 of the blue light source unit 20. The driving device 442 rotates the third diffusion plate 441 around a rotation axis C3.

[0041] The third diffusing plate 441 is disposed such that the diffusing surface 441a forms an angle of 45° with respect to each of the optical axis AX3 and the optical axis AX4. That is, the diffusing surface 441a is inclined at 45° with respect to the optical axis AX3 of the third condenser lens 43. Therefore, the chief ray of the red light LR emitted from the third condenser lens 43 is incident on the diffusing surface 441a at an incident angle of 45°.

[0042] As described above, the three diffusion plates 241, 341, and 441 have a common basic configuration, but differ from one another in parameters such as the number of layers and film thickness of the dielectric multilayer film, which results in the diffusion characteristics of the three dielectric multilayer films differing from one another.

[0043] Specifically, the dielectric multilayer film of the first diffusion plate 241 is the first dielectric multilayer film, the dielectric multilayer film of the second diffusion plate 341 is the second dielectric multilayer film, and the dielectric multilayer film of the third diffusion plate 441 is the third dielectric multilayer film. The first dielectric multilayer film has a characteristic that the reflectance in the blue wavelength band of light incident at an incident angle of 45° is higher than the reflectance in the green wavelength band and the reflectance in the red wavelength band of light incident at an incident angle of 45°. The second dielectric multilayer film has a characteristic that the reflectance in the green wavelength band of light incident at an incident angle of 45° is higher than the reflectance in the blue wavelength band and the reflectance in the red wavelength band of light incident at an incident angle of 45°. The third dielectric multilayer film has a characteristic that the reflectance in the red wavelength band of light incident at an incident angle of 45° is higher than the reflectance in the blue wavelength band and the reflectance in the green wavelength band of light incident at an incident angle of 45°. That is, each dielectric multilayer has a characteristic that the reflectance in the wavelength band of light incident on the dielectric multilayer is higher than the reflectance in other wavelength bands. The reflectance of the first dielectric multilayer in the blue wavelength band, the reflectance of the second dielectric multilayer in the green wavelength band, and the reflectance of the third dielectric multilayer in the red wavelength band are each 90% or more, preferably 95% or more. In this embodiment, 45° corresponds to the first incidence angle, the second incidence angle, and the third incidence angle in the claims.

[0044] The third collimator lens 45 is provided on the optical axis AX4 on the light exit side of the third diffuser plate 441. The third collimator lens 45 is composed of a convex lens. The third collimator lens 45 collimates the red light LR exiting from the third diffuser plate 441 at a predetermined diffusion angle, and outputs the parallel light toward the light combining element 50.

[0045] The light combining element 50 is provided at a position where the optical axis AX4 and the optical axis AX5 intersect. The light combining element 50 is composed of a cross dichroic prism. The cross dichroic prism has a first dichroic mirror 501 and a second dichroic mirror 502. The first dichroic mirror 501 and the second dichroic mirror 502 are arranged in a direction intersecting the optical axis AX4 and the optical axis AX5 at 45°. The first dichroic mirror 501 reflects the red light LR and transmits the green light LG and the blue light LB. The second dichroic mirror 502 reflects the blue light LB and transmits the green light LG and the red light LR. As a result, the light combining element 50 combines the blue light LB emitted from the first diffuser plate 241, the green light LG emitted from the second diffuser plate 341, and the red light LR emitted from the third diffuser plate 441, and emits white combined light LW toward the double-sided multi-lens array 60.

[0046] The blue light LB emitted from the blue laser diode array 21, the green light LG emitted from the green laser diode array 31, and the red light LR emitted from the red laser diode array 41 are linearly polarized light having a specific polarization direction. The polarization direction of the blue light LB, the polarization direction of the green light LG, and the polarization direction of the red light LR constituting the combined light LW are coincident with each other at the time of being emitted from the light combining element 50. Specifically, the polarization directions of the colored lights LB, LG, and LR are coincident with the direction perpendicular to the paper surface of FIG. 2. Therefore, the colored lights LB, LG, and LR are S-polarized light with respect to the dichroic mirrors 501 and 502 of the light combining element 50. With this configuration, the transmission loss of light at the entrance side polarizing plate of the light modulation devices 400R, 400G, and 400B can be reduced without using a polarization conversion element. In addition, by making the colored lights LB, LG, and LR S-polarized light with respect to the dichroic mirrors 501 and 502, the reflectance of the dichroic mirrors 501 and 502 can be increased.

[0047] The double-sided multi-lens array 60 and the superimposing lens 80 constitute an integrator optical system. The integrator optical system homogenizes the illuminance distribution of the combined light LW emitted from the light combining element 50 in the image forming regions of each of the red light optical modulator 400R, the green light optical modulator 400G, and the blue light optical modulator 400B.

[0048] The double-sided multi-lens array 60 is provided on the light exit side of the light combining element 50 on the optical axis AX5. The double-sided multi-lens array 60 is a multi-lens array in which a first multi-lens surface 60a and a second multi-lens surface 60b are integrated into one member. The first multi-lens surface 60a has a plurality of lenses for splitting the combined light LW exiting from the light combining element 50 into a plurality of partial light beams. The plurality of lenses are arranged in a matrix in a plane perpendicular to the optical axis AX5.

[0049] The second multi-lens surface 60b has a plurality of lenses corresponding to the plurality of lenses of the first multi-lens surface 60a. The second multi-lens surface 60b, together with the superimposing lens 80 at the rear stage, forms an image of each lens of the first multi-lens surface 60a in or near the image forming area of ​​each of the red light optical modulation device 400R, the green light optical modulation device 400G, and the blue light optical modulation device 400B. The plurality of lenses are arranged in a matrix in a plane perpendicular to the optical axis AX5. The first multi-lens surface 60a and the second multi-lens surface 60b may be provided separately as two multi-lens arrays.

[0050] The displacement device 70 displaces the double-sided multi-lens array 60 in a direction perpendicular to the optical axis AX5 (a direction along the XZ plane). The displacement device 70 is composed of a motor capable of vibrating or swinging the double-sided multi-lens array 60 at high speed. In the case of this embodiment, since the double-sided multi-lens array 60 is used instead of a multi-lens array made of two members, it is easy to displace the double-sided multi-lens array 60 by the displacement device 70. By vibrating or swinging the double-sided multi-lens array 60, it is possible to reduce speckles that tend to occur when using a laser diode.

[0051] The overlapping lens 80 collects each of the multiple partial light beams emitted from the double-sided multi-lens array 60 and overlaps them with each other in or near the image forming areas of each of the red light optical modulator 400R, the green light optical modulator 400G, and the blue light optical modulator 400B.

[0052] 1, the color separation light-guiding optical system 200 includes a dichroic mirror 240, a dichroic mirror 220, a reflecting mirror 210, a reflecting mirror 230, and a reflecting mirror 250. The color separation light-guiding optical system 200 separates the white combined light LW emitted from the illumination device 700 into red light LR, green light LG, and blue light LB, and guides the red light LR, green light LG, and blue light LB to the corresponding red light optical modulation device 400R, green light optical modulation device 400G, and blue light optical modulation device 400B, respectively.

[0053] A field lens 300R is disposed between the color separation light-guiding optical system 200 and the red light optical modulation device 400R. A field lens 300G is disposed between the color separation light-guiding optical system 200 and the green light optical modulation device 400G. A field lens 300B is disposed between the color separation light-guiding optical system 200 and the blue light optical modulation device 400B.

[0054] The dichroic mirror 240 reflects the blue light LB and transmits the red light LR and green light LG. The dichroic mirror 220 reflects the green light LG and transmits the blue light LB. The reflecting mirrors 210 and 230 each reflect the red light LR. The reflecting mirror 250 reflects the blue light LB.

[0055] The red light optical modulation device 400R is composed of a liquid crystal panel that modulates red light LR according to image information to form an image. The green light optical modulation device 400G is composed of a liquid crystal panel that modulates green light LG according to image information to form an image. The blue light optical modulation device 400B is composed of a liquid crystal panel that modulates blue light LB according to image information to form an image.

[0056] Although not shown, an incident side polarizing plate is arranged between the field lens 300R and the red light optical modulator 400R, between the field lens 300G and the green light optical modulator 400G, and between the field lens 300B and the blue light optical modulator 400B. An exit side polarizing plate is arranged between the red light optical modulator 400R and the synthesis optical system 500, between the green light optical modulator 400G and the synthesis optical system 500, and between the blue light optical modulator 400B and the synthesis optical system 500. The incident side polarizing plate does not need to be provided when the disturbance of polarization caused by the optical system after emission from the illumination device 700 is acceptable.

[0057] The combining optical system 500 combines the image lights emitted from the red light optical modulation device 400R, the green light optical modulation device 400G, and the blue light optical modulation device 400B. The combining optical system 500 is composed of a cross dichroic prism having a substantially square shape in a plan view, which is formed by bonding four right-angle prisms together. In the cross dichroic prism, a dielectric multilayer film is provided at the substantially X-shaped interface where the right-angle prisms are bonded together.

[0058] The image light emitted from the combining optical system 500 is enlarged and projected onto a screen SCR by a projection optical device 600. The projection optical device 600 is composed of a plurality of lenses.

[0059] [Effects of the first embodiment] The lighting device 700 of this embodiment includes a blue laser diode array 21 that emits blue light LB, a green laser diode array 31 that emits green light LG, a red laser diode array 41 that emits red light LR, a first diffusion plate 241 that diffusely reflects the blue light LB emitted from the blue laser diode array 21, a second diffusion plate 341 that diffusely reflects the green light LG emitted from the green laser diode array 31, a third diffusion plate 441 that diffusely reflects the red light LR emitted from the red laser diode array 41, and a light combining element 50 that combines the blue light LB emitted from the first diffusion plate 241, the green light LG emitted from the second diffusion plate 341, and the red light LR emitted from the third diffusion plate 441, and emits combined light LW. The first diffusion plate 241 has a first dielectric multilayer film that reflects the blue light LB. The second diffusion plate 341 has a second dielectric multilayer film that reflects the green light LG. The third diffusion plate 441 has a third dielectric multilayer film that reflects the red light LR. The first dielectric multilayer film has a characteristic that the reflectance in the blue wavelength band of light incident at an incident angle of 45° is higher than the reflectance in the green wavelength band and the reflectance in the red wavelength band of light incident at an incident angle of 45°. The second dielectric multilayer film has a characteristic that the reflectance in the green wavelength band of light incident at an incident angle of 45° is higher than the reflectance in the blue wavelength band and the reflectance in the red wavelength band of light incident at an incident angle of 45°. The third dielectric multilayer film has a characteristic that the reflectance in the red wavelength band of light incident at an incident angle of 45° is higher than the reflectance in the blue wavelength band and the reflectance in the green wavelength band of light incident at an incident angle of 45°.

[0060] Fig. 5 is a diagram showing an example of the spectral characteristics of a dielectric multilayer film. In the graph of Fig. 5, the horizontal axis is wavelength (nm) and the vertical axis is reflectance (%). Graph A shows the case where the incident angle is 0°, graph B shows the case where the incident angle is 20°, graph C shows the case where the incident angle is 40°, graph D shows the case where the incident angle is 60°, and graph E shows the case where the incident angle is 80°.

[0061] As shown in FIG. 5, the dielectric multilayer film of this example shows a stable reflectance of approximately 100% for light in the blue wavelength band of 420 to 460 nm, regardless of the incident angle. However, for light in a wavelength band exceeding 470 nm, the reflectance drops sharply at a specific incident angle and in a specific wavelength band. Thus, it is difficult to realize a dielectric multilayer film that has little incident angle dependency over a wide band from the blue wavelength band to the red wavelength band and can stably obtain a high reflectance. In order to obtain the desired characteristics, it is necessary to increase the number of dielectric films constituting the dielectric multilayer film to, for example, 50 layers or more, but even with such a configuration, there are problems such as a large amount of light absorption, failure to obtain a desired reflectance, a decrease in the reliability of the film, and a decrease in the yield of the film. Therefore, there was a problem that it was difficult to realize a highly efficient lighting device with the conventional configuration in which blue light, green light, and red light are combined and then the combined light is diffused by one diffusion plate.

[0062] In response to this problem, according to the present embodiment, a first dielectric multilayer film is provided on the first diffusion plate 241 on which the blue light LB is incident, a second dielectric multilayer film is provided on the second diffusion plate 341 on which the green light LG is incident, and a third dielectric multilayer film is provided on the third diffusion plate 441 on which the red light LR is incident, and each dielectric multilayer film has a higher reflectance in the wavelength band of the colored light incident on the dielectric multilayer film than in other wavelength bands. That is, a dielectric multilayer film having different reflectance characteristics is used for each of the different colored lights, and each dielectric multilayer film has a reflectance characteristic optimized for the wavelength band of the colored light incident on the dielectric multilayer film. This allows the use of a dielectric multilayer film that provides a stable reflectance only in a specific wavelength band for each diffusion plate 241, 341, 441, thereby realizing a highly efficient lighting device 700.

[0063] The projector 10 of this embodiment includes an illumination device 700 of this embodiment, light modulation devices 400R, 400G, and 400B that modulate light including a composite light LW emitted from the illumination device 700 in accordance with image information, and a projection optical device 600 that projects the light modulated by the light modulation devices 400R, 400G, and 400B.

[0064] According to this configuration, a projector 10 with excellent light utilization efficiency can be realized.

[0065] [Second embodiment] A second embodiment of the present invention will now be described with reference to FIGS. The basic configuration of the projector in the second embodiment is similar to that in the first embodiment, but the configuration of the illumination device is different from that in the first embodiment, so a description of the basic configuration of the projector will be omitted.

[0066] FIG. 6 is a schematic diagram of a lighting device 710 according to the second embodiment. In FIG. 6, the same components as those in FIG. 2 used in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

[0067] 6, the illumination device 710 of the present embodiment includes a blue light source unit 26, a green light source unit 27, a red light source unit 28, a light combining element 50, a double-sided multi-lens array 60, a displacement device 70, and a superimposing lens 80. The basic configuration of the illumination device 710 is similar to that of the illumination device 700 of the first embodiment, with the following differences.

[0068] Generally, the light emission efficiency of a laser diode differs for each color of light emitted, and therefore the light output of the laser diode also differs for each color of light emitted. For example, the light output of a blue laser diode is greater than that of a green laser diode and a red laser diode. On the other hand, the light output of each color of light required to obtain white light having a predetermined color temperature differs for each color of light emitted. For example, the light output of blue light required to obtain white light having a predetermined color temperature is smaller than that of green light and red light. Therefore, generally, the number of blue laser diodes is smaller than the number of green laser diodes and red laser diodes. Thus, in order to efficiently obtain white light having a predetermined color temperature, it is desirable to have the number of laser diodes differ for each color of light emitted.

[0069] For the above reasons, in the lighting device 710 of this embodiment, the number of laser diodes included in each of the light source units 26, 27, 28 is made different for each emission color. In this embodiment, the blue laser diode array 36 is composed of four blue laser diodes 211. The green laser diode array 31 is composed of 16 green laser diodes 311. The red laser diode array 38 is composed of 24 red laser diodes 411. In this way, the number of red laser diodes 411 is greater than the number of green laser diodes 311, and the number of green laser diodes 311 is greater than the number of blue laser diodes 211. With this configuration, white light having a predetermined color temperature can be obtained efficiently.

[0070] In Fig. 6, one blue laser diode 211 is shown, but four blue laser diodes 211 are arranged in a direction perpendicular to the paper. Similarly, four green laser diodes 311 are shown, but four rows of green laser diodes 311 are arranged in a direction perpendicular to the paper. Six red laser diodes 411 are shown, but four rows of red laser diodes 411 are arranged in a direction perpendicular to the paper. Therefore, Fig. 6 is a view seen from a direction in which the numbers of laser diodes of the three colors are different from each other, and when viewed from a direction perpendicular to Fig. 6, four laser diodes are arranged in each laser diode array.

[0071] In this embodiment, the diffusion characteristics of the diffusion plates 245, 345, and 445 of the diffusion devices 46, 47, and 48 are different from each other. Specifically, the diffusion characteristic of the first diffusion plate 245 for blue light LB is greater than the diffusion characteristic of the second diffusion plate 345 for green light LG, and the diffusion characteristic of the second diffusion plate 345 for green light LG is greater than the diffusion characteristic of the third diffusion plate 445 for red light LR. As an example, the light distribution characteristic of the light diffused by each of the diffusion plates 245, 345, and 445 is expressed as cos n When expressed as θ, the light distribution characteristic of the first diffusion plate 245 on which the blue light LB is incident is cos nθ:n=10. The light distribution characteristic of the second diffusion plate 345 onto which the green light LG is incident is cos n θ:n=12. The light distribution characteristic of the third diffusion plate 445 on which the red light LR is incident is cos n θ:n=15. According to this expression, the smaller the value of n, the greater the diffusivity. To realize such a difference in diffusion characteristics, the shape and dimensions of the uneven structure of each of the diffusion plates 245, 345, 445 may be made different from each other.

[0072] In this specification, the diffusivity is defined as the width of the full angle at half maximum, which is 50% of the maximum intensity of the diffused light, in the light intensity distribution curve after diffusion when parallel light is perpendicularly incident on the diffusion surface of the diffusion plate. FIG. 7 is a diagram showing an example of the light intensity distribution curve after diffusion. In FIG. 7, the horizontal axis is the diffusion angle (°) and the vertical axis is the light intensity (relative value). The diffusion angle width ω shown in FIG. 7 corresponds to the diffusivity defined above. Therefore, the larger the diffusion angle width ω, the larger the diffusivity, and the smaller the diffusion angle width ω, the smaller the diffusivity.

[0073] [Effects of the second embodiment] In this embodiment, too, a dielectric multilayer film that provides stable reflectance only in a specific wavelength band can be used for each of the diffusers 245, 345, and 445, thereby achieving the same effect as in the first embodiment, that is, a highly efficient lighting device 710 can be realized.

[0074] In particular, in the present embodiment, the incidence angle widths of the colored lights LB, LG, and LR incident on the respective diffusers 245, 345, and 445 are different from each other due to the difference in the number of laser diodes of each of the light source units 26, 27, and 28. As shown in FIG. 6, the incidence angle width of the blue light LB with respect to the first diffuser 245 is θ1, the incidence angle width of the green light LG with respect to the second diffuser 345 is θ2, and the incidence angle width of the red light LR with respect to the third diffuser 445 is θ3. Since the number of laser diodes is greater in the blue light source unit 26, the green light source unit 27, and the red light source unit 28 in this order, the diameters of the light beams emitted from the respective collimator lens arrays 22, 32, and 42 are greater in the order of the blue light LB, the green light LG, and the red light LR. Therefore, when the focal lengths of the respective condenser lenses 23, 33, and 43 are the same, the incidence angle widths of the colored lights LB, LG, and LR are greater in the order of the incidence angle width θ1, the incidence angle width θ2, and the incidence angle width θ3.

[0075] Here, in order to make the diffusion angles α1, α2, α3 of the color lights LB, LG, LR after diffusion equal, it is necessary to diffuse the blue light LB having a relatively small incident angle width relatively strongly and diffuse the red light LR having a relatively large incident angle width relatively weakly. Therefore, in this embodiment, the diffusion of the first diffusion plate 245 for the blue light LB is made larger than the diffusion of the second diffusion plate 345 for the green light LG, and the diffusion of the second diffusion plate 345 for the green light LG is made larger than the diffusion of the third diffusion plate 445 for the red light LR. This makes it possible to make the diffusion angles α1, α2, α3 of the color lights LB, LG, LR after diffusion equal, and to reduce the color unevenness of the composite light LW emitted from the lighting device 710.

[0076] [Third embodiment] Hereinafter, a third embodiment of the present invention will be described with reference to FIG. The basic configuration of the projector of the third embodiment is similar to that of the first embodiment, but the configuration of the illumination device is different from that of the first embodiment, so a description of the basic configuration of the projector will be omitted.

[0077] FIG. 8 is a schematic configuration diagram of an illumination device 720 according to the third embodiment. In FIG. 8, the same reference numerals are given to the components common to FIG. 2 used in the first embodiment, and the description thereof will be omitted.

[0078] As shown in FIG. 8, the lighting device 720 of the present embodiment includes a blue light source unit 55, a green light source unit 56, a red light source unit 57, a photosynthetic element 50, a double-sided multi-lens array 60, a displacement device 70, and a superimposing lens 80. The basic configuration of the lighting device 720 is the same as that of the lighting device 710 of the second embodiment, and the following points are different.

[0079] In the lighting device 720 of the present embodiment, the focal lengths F1, F2, and F3 of the condenser lenses 65, 66, and 67 provided in each light source unit 55, 56, and 57 are different for each emission color. Specifically, the focal length F1 of the first condenser lens 65 of the blue light source unit 55 is shorter than the focal length F2 of the second condenser lens 66 of the green light source unit 56. The focal length F2 of the second condenser lens 66 of the green light source unit 56 is shorter than the focal length F3 of the third condenser lens 67 of the red light source unit 57. That is, F1 < F2 < F3. Note that the focal length F1 may be equal to the focal length F2. That is, F1 ≦ F2 < F3 may be sufficient.

[0080] Furthermore, the outer diameter sizes D1, D2, and D3 of the condenser lenses 65, 66, and 67 provided in each light source unit 55, 56, and 57 may be different for each emission color. Specifically, the outer diameter size D1 of the first condenser lens 65 of the blue light source unit 55 may be smaller than the outer diameter size D2 of the second condenser lens 66 of the green light source unit 56. The outer diameter size D2 of the second condenser lens 66 of the green light source unit 56 may be smaller than the outer diameter size D3 of the third condenser lens 67 of the red light source unit 57. That is, D1 < D2 < D3 may be sufficient. Note that the outer diameter size D1 may be equal to the outer diameter size D2. That is, D1 ≦ D2 < D3 may be sufficient.

[0081] [Effects of the Third Embodiment] Also in the present embodiment, the same effects as those of the first embodiment can be obtained, such as that a dielectric multilayer film capable of obtaining a stable reflectance only in a specific wavelength band can be used for each diffusion plate 245, 345, and 445, and a highly efficient lighting device 720 can be realized.

[0082] In this embodiment, it is assumed that the focal length F3 of the third condenser lens 67 of the red light source unit 57 is equal to the focal length of the third condenser lens 43 of the second embodiment. In this case, for example, when focusing on the blue light source unit 55, the focal length F1 of the first condenser lens 65 is shorter than the focal length F5 of the first condenser lens 23 of the second embodiment shown in FIG. 6, so that the incident angle width θ4 of the blue light LB incident on the first diffuser plate 245 is larger than the incident angle width θ1 of the blue light LB of the second embodiment. Therefore, even if the diffusivity of the first diffuser plate 245 is not as large as that of the first diffuser plate 245 of the second embodiment, the diffusion angle α4 of the blue light LB after diffusion can be made equal to the diffusion angle α1 of the second embodiment. This makes it possible to easily design and manufacture the uneven structure of the first diffuser plate 245. Although the blue light source unit 55 has been given as an example above, the second diffuser plate 345 of the green light source unit 56 can also obtain the above-mentioned effects similar to those of the first diffuser plate 245.

[0083] Furthermore, for blue light source unit 55 and green light source unit 56, which have fewer laser diodes than red light source unit 57, the diameter of each light beam incident on each condenser lens 65, 66 is smaller than that of red light source unit 57, so that condenser lenses 65, 66 having a smaller outer diameter size than red light source unit 57 can be used. This allows the illumination device 720 to be made more compact.

[0084] The technical scope of the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. In addition, one aspect of the present invention can be a configuration in which the characteristic portions of the above-described embodiments are appropriately combined.

[0085] Although the lighting device of the above embodiment includes a rotatable diffusion plate, the diffusion plate does not necessarily have to be rotatable and may be of a fixed type.

[0086] In addition, the specific description of the shape, number, arrangement, material, etc. of each component of the lighting device and the projector is not limited to the above embodiment and can be changed as appropriate. In addition, in the above embodiment, an example in which the lighting device according to the present invention is mounted on a projector using a liquid crystal panel is shown, but this is not limited to this. The lighting device according to the present invention may be applied to a projector using a digital micromirror device as a light modulation device. In addition, the projector does not need to have multiple light modulation devices, and may be a single-panel projector having only one light modulation device.

[0087] In the above embodiment, the illumination device of the present invention is applied to a projector, but the present invention is not limited to this. The illumination device of the present invention can also be applied to lighting fixtures, automobile headlights, and the like.

[0088] [Summary of this disclosure] The following is a summary of this disclosure.

[0089] (Appendix 1) a first laser light source unit that emits a first light in a first wavelength band; a second laser light source unit that emits a second light in a second wavelength band different from the first wavelength band; A first diffusing member that diffuses and reflects the first light emitted from the first laser light source unit; A second diffusing member that diffuses and reflects the second light emitted from the second laser light source unit; a light combining element that combines the first light emitted from the first diffusing member and the second light emitted from the second diffusing member and emits a combined light; Equipped with the first diffusing member has a first dielectric multilayer film that reflects the first light, the second diffusing member has a second dielectric multilayer film that reflects the second light, When an incident angle of a chief ray of the first light incident on the first diffusing member is defined as a first incident angle, and an incident angle of a chief ray of the second light incident on the second diffusing member is defined as a second incident angle, the first dielectric multilayer film has a characteristic that a reflectance in the first wavelength band of light incident at the first incident angle is higher than a reflectance in the second wavelength band of light incident at the first incident angle; The second dielectric multilayer film has a characteristic that the reflectance in the second wavelength band of light incident at the second incident angle is higher than the reflectance in the first wavelength band of light incident at the second incident angle.

[0090] According to the configuration of Appendix 1, it is only necessary to use a dielectric multilayer film that exhibits high reflectance only in either the first wavelength band or the second wavelength band for each diffusion member, so that a highly efficient lighting device can be realized while the configuration of the dielectric multilayer film can be simplified.

[0091] (Appendix 2) a third laser light source unit that emits a third light of a third wavelength band different from the first wavelength band and the second wavelength band; a third diffusing member that diffuses and reflects the third light emitted from the third laser light source unit; Further equipped with the light combining element combines the first light, the second light, and the third light emitted from the third diffusing member; the third diffusing member has a third dielectric multilayer film that reflects the third light, When an incident angle of a chief ray of the third light incident on the third diffusing member is defined as a third incident angle, The lighting device described in Appendix 1, wherein the third dielectric multilayer film has a characteristic in which the reflectance in the third wavelength band of light incident at the third incident angle is higher than the reflectance in the first wavelength band and the reflectance in the second wavelength band of light incident at the third incident angle.

[0092] According to the configuration of Supplementary Note 2, the color gamut of the synthesized light can be expanded.

[0093] (Appendix 3) 3. The lighting device of claim 2, wherein the first wavelength band is a blue wavelength band, the second wavelength band is a green wavelength band, and the third wavelength band is a red wavelength band.

[0094] According to the configuration of Supplementary Note 3, it is possible to realize a lighting device that emits white light as the combined light.

[0095] (Appendix 4) each of the first laser light source unit, the second laser light source unit, and the third laser light source unit is composed of a laser diode; the number of the laser diodes constituting the third laser light source unit is greater than the number of the laser diodes constituting the second laser light source unit, 4. The lighting device according to claim 3, wherein the number of the laser diodes constituting the second laser light source section is greater than the number of the laser diodes constituting the first laser light source section.

[0096] According to the configuration of Supplementary Note 4, white light having a predetermined color temperature can be efficiently obtained according to the difference in the luminous efficiency of the solid-state light source.

[0097] (Appendix 5) The first diffusing member has a larger diffusivity for the first light than the second diffusing member has a diffusivity for the second light, 5. The lighting device according to claim 4, wherein the second diffusing member has a greater diffusivity for the second light than the third diffusing member has a diffusivity for the third light.

[0098] According to the configuration of Supplementary Note 5, the light distribution angles of the respective light beams after diffusion can be made equal, and color unevenness of the combined light emitted from the lighting device can be reduced.

[0099] (Appendix 6) a first condensing lens that condenses the first light emitted from the first laser light source unit and emits the first light toward the first diffusing member; a second condenser lens that condenses the second light emitted from the second laser light source unit and emits the second light toward the second diffusion member; a third condenser lens that condenses the third light emitted from the third laser light source unit and emits the third light toward the third diffusion member; 6. The lighting device of claim 3, further comprising:

[0100] According to the configuration of Supplementary Note 6, the size of each diffusion member can be reduced.

[0101] (Appendix 7) a focal length of the first condenser lens is equal to or less than a focal length of the second condenser lens; 7. The illumination device according to claim 6, wherein a focal length of the second condenser lens is shorter than a focal length of the third condenser lens.

[0102] According to the configuration of Supplementary Note 7, since there is no need to unnecessarily increase the diffusivity of the first diffusing member and the second diffusing member, it is possible to facilitate the design and manufacture of the diffusing structures of the first diffusing member and the second diffusing member.

[0103] (Appendix 8) an outer diameter size of the first condenser lens is equal to or smaller than an outer diameter size of the second condenser lens, 8. The illumination device according to claim 6 or 7, wherein an outer diameter size of the second condenser lens is smaller than an outer diameter size of the third condenser lens.

[0104] According to the configuration of Supplementary Note 8, the lighting device can be made smaller.

[0105] (Appendix 9) The lighting device according to any one of claims 2 to 8, wherein each of the first diffusing member, the second diffusing member, and the third diffusing member has a light-transmitting substrate and a dielectric multilayer film.

[0106] According to the configuration of Supplementary Note 9, the manufacturing process of each diffusing member can be simplified.

[0107] (Appendix 10) The lighting device described in any one of Appendix 2 to Appendix 8, wherein each of the first diffusing member, the second diffusing member, and the third diffusing member has a translucent substrate, a metal film, and a dielectric multilayer film.

[0108] According to the configuration of Supplementary Note 10, the metal film and the dielectric multilayer film can perform the reflection function, so that the number of layers in the dielectric multilayer film can be reduced.

[0109] (Appendix 11) The lighting device according to any one of claims 2 to 8, wherein each of the first diffusing member, the second diffusing member, and the third diffusing member has a metal substrate and a dielectric multilayer film.

[0110] According to the configuration of Supplementary Note 11, the configuration of each diffusion member can be simplified.

[0111] (Appendix 12) each of the first light, the second light, and the third light is linearly polarized light; 12. The lighting device according to claim 2, wherein a polarization direction of the first light contained in the combined light, a polarization direction of the second light contained in the combined light, and a polarization direction of the third light contained in the combined light are consistent with each other.

[0112] According to the configuration of Supplementary Note 12, the incident-side polarizing plate can be omitted, and optimal illumination light can be formed for a light modulation device using polarized light such as a liquid crystal panel.

[0113] (Appendix 13) The lighting device described in any one of Appendix 2 to Appendix 12, further comprising a driving device that rotates each of the first diffusion member, the second diffusion member, and the third diffusion member about a rotation axis that intersects the diffusion surface.

[0114] According to the configuration of Supplementary Note 13, it is possible to reduce speckles caused by using a solid-state light source.

[0115] (Appendix 14) a double-sided multi-lens array provided on the exit side of the light combining element; a displacement device that displaces the double-sided multi-lens array in a direction intersecting an optical axis; 14. The lighting device of any one of claims 1 to 13, further comprising:

[0116] According to the configuration of Supplementary Note 14, speckles caused by using a solid-state light source can be reduced.

[0117] (Appendix 15) An illumination device according to any one of claims 1 to 14, a light modulation device that modulates light including the composite light emitted from the illumination device in accordance with image information; a projection optical device that projects the light modulated by the light modulation device; A projector equipped with

[0118] According to the configuration of Supplementary Note 15, a projector with high light utilization efficiency can be realized. [Explanation of symbols]

[0119] 10... projector, 20, 26, 55... blue light source unit (first laser light source unit), 23, 65... first condensing lens, 30, 27, 56... green light source unit (second laser light source unit), 33, 66... ​​second condensing lens, 40, 28, 57... red light source unit (third laser light source unit), 43, 67... third condensing lens, 50... light combining element, 60... double-sided multi-lens array, 70... displacement device, 211... blue laser diode, 241, 245... first diffusion plate (first diffusion member), 242, 342, 442... driving device, 24 3...transparent substrate, 244...metal reflective film, 245...dielectric multilayer film, 311...green laser diode, 341, 345...second diffuser plate (second diffuser member), 411...red laser diode, 441, 445...third diffuser plate (third diffuser member), 400R...red light optical modulator, 400G...green light optical modulator, 400B...blue light optical modulator, 600...projection optical device, 700, 710, 720...illumination device, LB...blue light (first light), LG...green light (second light), LR...red light (third light), LW...synthetic light.

Claims

1. a first laser light source unit that emits a first light in a first wavelength band; a second laser light source unit that emits a second light in a second wavelength band different from the first wavelength band; A first diffusing member that diffuses and reflects the first light emitted from the first laser light source unit; A second diffusing member that diffuses and reflects the second light emitted from the second laser light source unit; a light combining element that combines the first light emitted from the first diffusing member and the second light emitted from the second diffusing member and emits a combined light; Equipped with the first diffusing member has a first dielectric multilayer film that reflects the first light, the second diffusing member has a second dielectric multilayer film that reflects the second light, When an incident angle of a chief ray of the first light incident on the first diffusing member is defined as a first incident angle, and an incident angle of a chief ray of the second light incident on the second diffusing member is defined as a second incident angle, the first dielectric multilayer film has a characteristic that a reflectance in the first wavelength band of light incident at the first incident angle is higher than a reflectance in the second wavelength band of light incident at the first incident angle, The second dielectric multilayer film has a characteristic that the reflectance in the second wavelength band of light incident at the second incident angle is higher than the reflectance in the first wavelength band of light incident at the second incident angle.

2. a third laser light source unit that emits a third light of a third wavelength band different from the first wavelength band and the second wavelength band; A third diffusing member that diffuses and reflects the third light emitted from the third laser light source unit; Further equipped with the light combining element combines the first light, the second light, and the third light emitted from the third diffusing member; the third diffusing member has a third dielectric multilayer film that reflects the third light, When an incident angle of a chief ray of the third light incident on the third diffusing member is defined as a third incident angle, 2. The lighting device according to claim 1, wherein the third dielectric multilayer film has a characteristic in which the reflectance in the third wavelength band of light incident at the third incident angle is higher than the reflectance in the first wavelength band and the reflectance in the second wavelength band of light incident at the third incident angle.

3. 3. The illumination device of claim 2, wherein the first waveband is a blue waveband, the second waveband is a green waveband, and the third waveband is a red waveband.

4. each of the first laser light source unit, the second laser light source unit, and the third laser light source unit is constituted by a laser diode; the number of the laser diodes constituting the third laser light source unit is greater than the number of the laser diodes constituting the second laser light source unit, The illumination device according to claim 3 , wherein the number of the laser diodes constituting the second laser light source section is greater than the number of the laser diodes constituting the first laser light source section.

5. The first diffusing member has a larger diffusivity for the first light than the second diffusing member has a diffusivity for the second light, The lighting device according to claim 4 , wherein the second diffusing member has a diffusivity for the second light that is greater than a diffusivity for the third light that is greater than a diffusivity for the third light that is greater than a diffusing characteristic ....

6. a first condensing lens that condenses the first light emitted from the first laser light source unit and emits the first light toward the first diffusing member; a second condenser lens that condenses the second light emitted from the second laser light source unit and emits the second light toward the second diffusion member; a third condenser lens that condenses the third light emitted from the third laser light source unit and emits the third light toward the third diffusion member; The lighting device according to claim 3 , further comprising:

7. a focal length of the first condenser lens is equal to or less than a focal length of the second condenser lens, The illumination device according to claim 6 , wherein a focal length of the second condenser lens is shorter than a focal length of the third condenser lens.

8. an outer diameter size of the first condenser lens is equal to or smaller than an outer diameter size of the second condenser lens, The illumination device according to claim 6 , wherein an outer diameter of the second condenser lens is smaller than an outer diameter of the third condenser lens.

9. 4. The lighting device according to claim 2, wherein each of the first diffusing member, the second diffusing member, and the third diffusing member includes a light-transmitting substrate and a dielectric multilayer film.

10. 4. The lighting device according to claim 2, wherein each of the first diffusing member, the second diffusing member, and the third diffusing member includes a light-transmitting substrate, a metal film, and a dielectric multilayer film.

11. 4. The lighting device according to claim 2, wherein each of the first diffusing member, the second diffusing member, and the third diffusing member includes a metal substrate and a dielectric multilayer film.

12. each of the first light, the second light, and the third light is linearly polarized light; 4. The lighting device according to claim 2, wherein a polarization direction of the first light contained in the combined light, a polarization direction of the second light contained in the combined light, and a polarization direction of the third light contained in the combined light are consistent with each other.

13. The lighting device according to claim 2 , further comprising a driving device that rotates each of the first diffusing member, the second diffusing member, and the third diffusing member about a rotation axis that intersects with a diffusing surface.

14. a double-sided multi-lens array provided on the exit side of the light combining element; a displacement device that displaces the double-sided multi-lens array in a direction intersecting an optical axis; The lighting device according to claim 1 or 2, further comprising:

15. The lighting device according to claim 1 or 2, a light modulation device that modulates light including the composite light emitted from the illumination device in accordance with image information; a projection optical device that projects the light modulated by the light modulation device; A projector equipped with

Images