Light source device and projector

Abstract

To provide a light source device and a projector that are compact and generate white illumination light.SOLUTION: A light source device comprises: a first light source that emits first light; a light separation optical system that separates the first light into a first light flux and a second light flux, which travel along optical paths parallel to each other; an optical member through which the first light flux and the second light flux incident from the light separation optical system transmit; a light condensing optical system that condenses the first light flux and the second light flux transmitting through the optical member, respectively; and a light scattering element on which the first light flux and the second light flux emitted from the light condensing optical system are incident at different positions. The light scattering element includes: a substrate having a reflection surface reflecting light; a first wavelength conversion layer that is arranged on the reflection surface and converts the second light flux incident from the light condensing optical system into second light of a wavelength band different from the first light; and a light scattering layer that is arranged in a first direction along the reflection surface of the first wavelength conversion layer and scatters the first light flux incident from the light condensing optical system. The optical member reflects the light emitted from the light scattering element and transmitting through the light condensing optical system.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a light source device and a projector. [Background technology]

[0002] As a light source device for use in a projector, a light source device that generates illumination light using fluorescence generated in a phosphor layer has been proposed. The following Patent Document 1 discloses a light source device that includes a light source unit, a separation / synthesis element that separates light emitted from the light source unit into two orthogonal directions based on the polarization components, a diffuser onto which one of the polarization components separated by the separation / synthesis element is incident, and a phosphor onto which the other polarization component separated by the separation / synthesis element is incident as excitation light. In this light source device, the separation / synthesis element combines the light diffused by the diffuser and the fluorescence emitted from the phosphor to generate illumination light. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-79820 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the above light source device, the diffuser and the phosphor are arranged in two directions perpendicular to the separation / combining element, and therefore, there was a problem that the device configuration became large due to the arrangement of optical components in two mutually perpendicular directions. [Means for solving the problem]

[0005] In order to solve the above problems, a light source device according to one embodiment of the present invention includes a first light source that emits a first light, a light separation optical system that separates the first light emitted from the first light source into a first light beam and a second light beam traveling along parallel optical paths, an optical element that passes the first light beam and the second light beam incident from the light separation optical system, a focusing optical system that focuses the first light beam and the second light beam that have passed through the optical element, respectively, and a light scattering element onto which the first light beam and the second light beam emitted from the focusing optical system are incident at different positions, wherein the light scattering element has a substrate having a reflective surface that reflects light, a first wavelength conversion layer that is disposed on the reflective surface and converts the second light beam incident by the focusing optical system into a second light of a wavelength band different from the wavelength band of the first light, and a light scattering layer that is disposed in a first direction along the reflective surface of the first wavelength conversion layer and scatters the first light beam incident by the focusing optical system, and the optical element reflects the light emitted from the light scattering element and passing through the focusing optical system.

[0006] A light source device according to another aspect of the present invention includes a first light source that emits a first light composed of coherent light, a second light source that emits a second light composed of incoherent light, an optical member that passes the first light and the second light that are incident parallel to each other, a focusing optical system that focuses the first light and the second light that have passed through the optical member, and a light scattering element onto which the first light and the second light emitted from the focusing optical system are incident at different positions, the light scattering element including a substrate having a reflective surface that reflects light, and a light scattering element disposed on the reflective surface and coupled to the focusing optical system. and a light scattering layer arranged in a direction along the reflective surface of the first wavelength conversion layer and scattering the second light incident thereon by the focusing optical system, wherein the optical member reflects light emitted from the light scattering element and passed through the focusing optical system, and the degree of light scattering of the light scattering layer is adjusted so that the angular distribution of the third light emitted from the first wavelength conversion layer and the angular distribution of the scattered light of the second light emitted from the light scattering layer are brought closer to each other.

[0007] Another aspect of the projector of the present invention is a projector comprising a light source device of the above aspect, a light modulation device that modulates the illumination light emitted from the light source device based on image information, and a projection optical device that projects the image light modulated by the light modulation device. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic configuration diagram showing a projector according to a first embodiment. [Diagram 2] FIG. 2 is a schematic diagram showing a light source device. [Diagram 3] 3 is a plan view of a light incident surface of a light scattering element. FIG. [Figure 4] FIG. 11 is a schematic configuration diagram showing a light source device according to a second embodiment. [Diagram 5] FIG. 11 is a schematic configuration diagram showing a light source device according to a third embodiment. [Figure 6] FIG. 13 is a schematic configuration diagram showing a light source device according to a fourth embodiment. [Figure 7] FIG. 13 is a schematic configuration diagram showing a light source device according to a fifth embodiment. [Figure 8] FIG. 13 is a schematic configuration diagram showing a light source device according to a sixth embodiment. [Figure 9] FIG. 13 is a plan view showing the configuration of a light scattering element of the sixth embodiment. [Figure 10] FIG. 13 is a schematic configuration diagram showing a light source device according to a seventh embodiment. [Figure 11] FIG. 13 is a schematic configuration diagram showing a light source device according to an eighth embodiment. [Figure 12] FIG. 13 is a schematic configuration diagram showing a light source device according to a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. Note that the drawings used in the following description may show characteristic parts in an enlarged scale for the sake of convenience in order to make the characteristics easier to understand, and the dimensional ratios of each component may not necessarily be the same as in reality.

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

[0011] The light source device 2 emits white illumination light WL toward the color separation optical system 3. The configuration of the light source device 2 will be described in detail later.

[0012] The color separation optical system 3 separates the illumination light WL emitted from the light source device 2 into red light LR, green light LG, and blue light LB. The color separation optical system 3 includes a first dichroic mirror 7a, a second dichroic mirror 7b, a first reflecting mirror 8a, a second reflecting mirror 8b, a third reflecting mirror 8c, a first relay lens 9a, and a second relay lens 9b.

[0013] The first dichroic mirror 7a separates the illumination light WL from the light source device 2 into red light LR and light containing green light LG and blue light LB. The first dichroic mirror 7a transmits the red light LR and reflects the light containing green light LG and blue light LB. On the other hand, the second dichroic mirror 7b reflects the green light LG and transmits the blue light LB. In this way, the second dichroic mirror 7b separates the light containing green light LG and blue light LB into green light LG and blue light LB.

[0014] The first reflecting mirror 8a is disposed in the optical path of the red light LR and reflects the red light LR transmitted through the first dichroic mirror 7a toward the optical modulation device 4R. On the other hand, the second reflecting mirror 8b and the third reflecting mirror 8c are disposed in the optical path of the blue light LB and guide the blue light LB transmitted through the second dichroic mirror 7b to the optical modulation device 4B. The green light LG is reflected from the second dichroic mirror 7b toward the optical modulation device 4G.

[0015] The first relay lens 9a is disposed between the second dichroic mirror 7b and the second reflecting mirror 8b in the optical path of the blue light LB. The second relay lens 9b is disposed between the second reflecting mirror 8b and the third reflecting mirror 8c in the optical path of the blue light LB. The first relay lens 9a and the second relay lens 9b compensate for the optical loss of the blue light LB caused by the optical path length of the blue light LB being longer than the optical path lengths of the red light LR and the green light LG.

[0016] The light modulation device 4R modulates the red light LR according to image information to form image light corresponding to the red light LR. The light modulation device 4G modulates the green light LG according to image information to form image light corresponding to the green light LG. The light modulation device 4B modulates the blue light LB according to image information to form image light corresponding to the blue light LB.

[0017] For example, a transmissive liquid crystal panel is used for each of the light modulation device 4R, the light modulation device 4G, and the light modulation device 4B. Furthermore, a polarizing plate (not shown) is disposed on each of the incident side and the exit side of the liquid crystal panel.

[0018] A field lens 10R is disposed on the incident side of the optical modulation device 4R. The field lens 10R collimates the red light LR incident on the optical modulation device 4R. A field lens 10G is disposed on the incident side of the optical modulation device 4G. The field lens 10G collimates the green light LG incident on the optical modulation device 4G. A field lens 10B is disposed on the incident side of the optical modulation device 4B. The field lens 10B collimates the blue light LB incident on the optical modulation device 4B.

[0019] The image light emitted from the light modulation device 4R, the light modulation device 4G, and the light modulation device 4B is incident on the combining optical system 5. The combining optical system 5 combines the image light corresponding to the red light LR, the green light LG, and the blue light LB, respectively, and emits the combined image light toward the projection optical device 6. The combining optical system 5 uses, for example, a cross dichroic prism.

[0020] The projection optical device 6 has a plurality of projection lenses. The projection optical device 6 enlarges and projects the image light combined by the combining optical system 5 onto the screen SCR. As a result, an enlarged image is displayed on the screen SCR.

[0021] The configuration of the light source device 2 will be described below. FIG. 2 is a schematic diagram showing the configuration of a light source device 2 of the present embodiment. In the following description, an XYZ Cartesian coordinate system is used as the coordinate axes. The axis along the direction in which the illumination light WL is emitted from the light source device 2 corresponds to the X axis, the axis along the direction in which light is emitted from a light scattering element described later corresponds to the Y axis, and the axis along the direction perpendicular to the X axis and the Y axis corresponds to the Z axis. The illumination optical axis 100ax of the light source device 2 is an axis parallel to the X axis.

[0022] As shown in FIG. 2, the light source device 2 includes a first light source 21, a light separation optical system 22, an optical member 23, a light collection optical system 24, a light scattering element 25, and a uniform illumination optical system 30. The first light source 21 is composed of a semiconductor laser 21a that emits a blue light beam made of a laser beam. The blue light beam is, for example, a laser beam having a blue wavelength band of 440 to 490 nm. In this way, the first light source 21 is configured to emit blue light E made of a blue light beam as the first light. As the semiconductor laser 21a, a semiconductor laser that emits blue light of a wavelength other than 445 nm, for example, 455 nm or 460 nm, may be used. Also, instead of the semiconductor laser, other solid-state light sources such as LEDs (Light Emitting Diodes) may be used. The optical axis of the first light source 21 is an axis along the X-axis, and the direction in which the first light source 21 emits the blue light E is the -X direction.

[0023] The light separation optical system 22 separates the blue light E emitted from the first light source 21 into a first light flux E1 and a second light flux E2. The light separation optical system 22 has a first reflecting element 22a and a second reflecting element 22b. The first reflecting element 22a is disposed at an angle of 45 degrees with respect to the optical axis of the blue light E. The second reflecting element 22b is disposed in the -X direction of the first reflecting element 22a so as to face the first reflecting element 22a.

[0024] The first reflecting element 22a is composed of a half mirror that reflects a part of the blue light E and transmits the remaining part. The first reflecting element 22a transmits a part of the blue light E incident from the first light source 21 in the -Y direction as a first light beam E1, and reflects the remaining part of the blue light E in the -X direction as a second light beam E2.

[0025] The second light flux E2 reflected by the first reflecting element 22a is incident on the second reflecting element 22b. The second reflecting element 22b is composed of a mirror that reflects the second light flux E2. The second reflecting element 22b reflects the second light flux E2 in the -Y direction. The first light beam E1 and the second light beam E2 thus separated from the blue light E by the light separation optical system 22 travel along optical paths parallel to each other and enter the optical member . The ratio of the first light beam E1 and the second light beam E2 separated from the blue light E in the light separation optical system 22 can be appropriately changed by adjusting the transmittance of the first reflecting element 22a, etc., according to the white balance of the illumination light WL generated by the light source device 2. "Parallel" means that the optical paths are aligned with each other, and also includes the case where the optical paths form an angle with each other on the extension line.

[0026] The optical member 23 passes the first light beam E1 and the second light beam E2 incident from the light separation optical system 22. The first light beam E1 and the second light beam E2 transmitted through the optical member 23 are incident on the light collecting optical system 24. The light collecting optical system 24 collects the first light beam E1 and the second light beam E2 and guides them to the light scattering element 25. The light collecting optical system 24 also approximately collimates the light emitted from the light scattering element 25. The light collecting optical system 24 includes a convex lens 24a having a positive power. The light collecting optical system 24 in this embodiment includes one convex lens 24a, but may include multiple convex lenses.

[0027] The optical member 23 includes a first region 23A on which the first light flux E1 is incident and a second region 23B on which the second light flux E2 is incident. The second region 23B is located on the opposite side of the first region 23A with respect to the center 23C of the optical member 23. In the present embodiment, the first region 23A is located in the +X direction with respect to the center 23C of the optical member 23, and the second region 23B is located in the -X direction with respect to the center 23C of the optical member 23. The center 23C of the optical member 23 coincides with the optical axis 24AX of the focusing optical system 24. In other words, the first region 23A and the second region 23B are arranged to sandwich the optical axis 24AX of the focusing optical system 24.

[0028] Here, it is assumed that the first region 23A and the second region 23B are disposed on one side of the optical axis 24AX. In this case, the radius of the light collecting optical system 24 needs to be large enough to contain the first light flux E1 and the second light flux E2 transmitted through the first region 23A and the second region 23B, which causes a problem that the outer diameter of the light collecting optical system 24 becomes large. On the other hand, when the first region 23A and the second region 23B are disposed on both sides of the optical axis 24AX as described above, the light collecting optical system 24 can efficiently contain the first light flux E1 and the second light flux E2, so that the outer diameter of the light collecting optical system 24 can be prevented from becoming large.

[0029] The first light beam E1 and the second light beam E2 are incident on different regions of the convex lens 24a. The first light beam E1 and the second light beam E2 are incident on regions of the convex lens 24a that are different in distance from the optical axis 24AX in the radial direction of the convex lens 24a. In other words, the distance between the chief ray of the first light beam E1 and the center of the convex lens 24a is different from the distance between the chief ray of the second light beam E2 and the center of the convex lens 24a.

[0030] The first light beam E1 and the second light beam E2 emitted from the collecting optical system 24 are incident on the light scattering element 25. Fig. 3 is a plan view of the light incident surface 25a of the light scattering element 25. In Fig. 3, in order to explain the positional relationship between the light scattering element 25 and the collecting optical system 24, the collecting optical system 24 is illustrated by a two-dot chain line.

[0031] As shown in FIG. 3, the light scattering element 25 has a substrate 250, a first wavelength conversion layer 251, and a light scattering layer 252. The light incident surface 25a of the light scattering element 25 is the surface of the first wavelength conversion layer 251 and the light scattering layer 252 opposite to the substrate 250. The substrate 250 has a substantially square outer shape. The first wavelength conversion layer 251 and the light scattering layer 252 have a substantially rectangular outer shape and are of equal size. The light scattering layer 252 is disposed in the +X direction, which is a first direction along the reflecting surface 250a of the first wavelength conversion layer 251. The first wavelength conversion layer 251 and the light scattering layer 252 form a substantially square outer shape as a whole.

[0032] Here, the center of the substrate 250 is defined as the center 25C of the light scattering element 25. In this case, the boundary between the first wavelength conversion layer 251 and the light scattering layer 252 is located on the center 25C of the light scattering element 25.

[0033] The substrate 250 is made of a metal plate having excellent heat dissipation properties, such as aluminum or copper, and has a reflective surface 250a that reflects light. The reflective surface 250a is formed by forming a reflective film on the surface of the substrate 250.

[0034] 2, the first wavelength conversion layer 251 is disposed on the reflecting surface 250a of the substrate 250. As described below, the first wavelength conversion layer 251 receives the second light beam E2 in the blue wavelength band from the light collecting optical system 24 and converts the second light beam E2 into fluorescence Y in a different wavelength band.

[0035] The first wavelength conversion layer 251 may contain a ceramic phosphor or a single crystal phosphor. The wavelength band of the fluorescence Y has a peak wavelength in the range of 500 to 680 nm, for example. That is, the fluorescence Y is yellow light containing a green light component and a red light component.

[0036] The first wavelength conversion layer 251 contains, for example, an yttrium-aluminum-garnet (YAG) phosphor. Taking YAG:Ce containing cerium (Ce) as an activator as an example, the first wavelength conversion layer 251 can be made of a material obtained by mixing raw material powders containing constituent elements such as Y2O3, Al2O3, and CeO3 and reacting them in a solid state, Y-Al-O amorphous particles obtained by a wet method such as a coprecipitation method or a sol-gel method, or YAG particles obtained by a gas phase method such as a spray drying method, a flame pyrolysis method, or a thermal plasma method. Note that when a porous sintered body is used as the first wavelength conversion layer 251, light is scattered inside the phosphor and is difficult to propagate in the lateral direction, which is desirable from the viewpoint of light utilization efficiency.

[0037] As described below, the first light flux E1 is incident on the light scattering layer 252 from the light collecting optical system 24, and the light scattering layer 252 emits blue scattered light E1s by scattering the first light flux E1. The light scattering layer 252 includes a base material and a plurality of scatterers dispersed in the base material. The base material is made of a material having high light transmittance, for example, an inorganic material such as glass, or an organic material such as resin. For the scatterers, for example, particles having a high refractive index, such as titanium oxide or zinc oxide, can be suitably used.

[0038] A distance D in the Y-axis direction along the optical axis 24AX of the light collecting optical system 24 between the principal point 24C of the light collecting optical system 24 and the light incident surface 25a of the light scattering element 25 is different from a focal length F of the light collecting optical system 24. In other words, the light collecting optical system 24 is disposed with respect to the light scattering element 25 so as to cause the first light flux E1 and the second light flux E2 to be incident in a defocused state in which the first light flux E1 and the second light flux E2 are not in focus with respect to the light incident surface 25a of the light scattering element 25. The distance D may be greater than the focal length F.

[0039] Here, the farther the collecting optical system 24 is from the light scattering element 25, the larger the outer diameter needs to be in order to capture the light emitted from the light scattering element 25. In the case of this embodiment, the distance D is shorter than the focal length F of the collecting optical system 24, and therefore the distance between the collecting optical system 24 and the light scattering element 25 can be made closer than when the distance D is longer than the focal length F. Therefore, in the case of this embodiment, the light emitted from the light scattering element 25 can be efficiently captured while the outer diameter of the collecting optical system 24 is made smaller.

[0040] The first light beam E1 and the second light beam E2 in the defocused state do not form a focus on the light incident surface 25a of the light scattering element 25. For this reason, the illumination spot SP1 formed on the light incident surface 25a by the first light beam E1 and the irradiation spot SP2 formed on the light incident surface 25a by the second light beam E2 are disposed at positions spaced apart from each other by different distances in a direction perpendicular to the optical axis 24AX of the focusing optical system 24.

[0041] 2, the light-collecting optical system 24 can collect the first light flux E1 and the second light flux E2 and guide them to different positions on the light incident surface 25a of the light-scattering element 25. Thus, the light-collecting optical system 24 causes the first light flux E1 to be incident on the light-scattering layer 252 of the light-scattering element 25, and causes the second light flux E2 to be incident on the first wavelength conversion layer 251 of the light-scattering element 25.

[0042] The positional relationship between the light collecting optical system 24 and the light scattering element 25 will be described in more detail below. 2 and 3, the light collecting optical system 24 and the light scattering element 25 are arranged such that the optical axis 24AX is shifted in the -X direction with respect to the center 25C of the light scattering element 25. That is, the optical axis 24AX of the light collecting optical system 24 is located on the first wavelength conversion layer 251 of the light scattering element 25.

[0043] Here, the distance in the X-axis direction between a first position P1, which is the incident position of the second light flux E2 in the light scattering element 25, and a second position P2, which is the intersection point of the optical axis 24AX of the light collecting optical system 24 and the light scattering element 25, intersecting the optical axis 24AX, is defined as a first distance D1. The distance in the X-axis direction between a third position P3, which is the incident position of the first light flux E1 in the light scattering element 25, and the second position P2 is defined as a second distance D2. In this embodiment, the first distance D1 is shorter than the second distance D2. That is, the second light flux E2 incident as excitation light is incident at a position closer to the optical axis 24AX than the first light flux E1.

[0044] Since the first light flux E1 is incident on the light scattering layer 252 from an oblique direction facing the -X direction and the -Y direction, the light scattering layer 252 emits blue scattered light E1s, which is obtained by scattering the first light flux E1, in an oblique direction facing the -X direction and the +Y direction with respect to the focusing optical system 24. In the focusing optical system 24 of this embodiment, the optical axis 24AX is located on the first wavelength conversion layer 251 side (-X side). Therefore, the focusing optical system 24 is disposed at a position shifted to the emission side of the blue scattered light E1s, so that the blue scattered light E1s can be efficiently incident on the focusing optical system 24. Therefore, the blue scattered light E1s is approximately parallelized by the focusing optical system 24, travels along the optical axis 24AX, and enters the optical member 23.

[0045] Furthermore, the first wavelength conversion layer 251 emits fluorescence Y obtained by wavelength-converting the second light flux E2 in all directions at a wide radiation angle by Lambertian emission. The light-collecting optical system 24 of this embodiment can cause the second light flux E2 to be incident closer to the optical axis 24AX while positioning the optical axis 24AX on the first wavelength conversion layer 251. In other words, the emission center of the fluorescence Y approaches the optical axis 24AX of the light-collecting optical system 24, and therefore the light-collecting optical system 24 can efficiently capture the fluorescence Y emitted at a wide radiation angle by Lambertian emission. Therefore, the fluorescence Y is substantially collimated by the light collecting optical system 24, travels along the optical axis 24AX, and enters the optical member 23.

[0046] The optical member 23 of this embodiment has a first optical section 231 and a second optical section 232. The first optical section 231 is configured with a dichroic mirror made of a dielectric multilayer film that transmits the first light beam E1 and the second light beam E2 and reflects the fluorescence Y. The first optical section 231 is disposed so as to form an angle of 45 degrees with respect to the optical axis 24AX of the focusing optical system 24.

[0047] The fluorescence Y collimated by the collecting optical system 24 is reflected by the first optical unit 231 in the +X direction and enters the uniform illumination optical system 30. In addition, since the blue scattered light E1s collimated by the collecting optical system 24 is light of the same blue wavelength as the first light beam E1, the first optical unit 231 transmits the blue scattered light E1s. The blue scattered light E1s that has transmitted through the first optical unit 231 is incident on the second optical unit 232 that is disposed in the +Y direction of the first optical unit 231. The second optical unit 232 is disposed so as to form an angle of 45 degrees with respect to the optical axis 24AX of the collecting optical system 24.

[0048] The second optical unit 232 reflects the blue scattered light E1s in the +X direction. The blue scattered light E1s reflected by the second optical unit 232 in the +X direction passes through the first optical unit 231 and enters the uniform illumination optical system 30. In other words, the second optical unit 232 generates white illumination light WL by guiding the blue scattered light E1s in the same direction as the fluorescence Y reflected by the first optical unit 231, i.e., to the optical path of the fluorescence Y. With this configuration, the optical paths of the blue scattered light E1s and the fluorescence Y are aligned, thereby making it possible to suppress color unevenness in the illumination light WL. The second optical section 232 is disposed at a position not overlapping with the optical paths of the first light flux E1 and the second light flux E2. Therefore, the second optical section 232 does not block the first light flux E1 and the second light flux E2 traveling toward the light scattering element 25.

[0049] In this manner, the optical member 23 reflects the blue scattered light E1s and the fluorescent light Y, which are light emitted from the light scattering element 25, and causes them to be incident as illumination light WL into the uniform illumination optical system 30. The optical member 23 and the uniform illumination optical system 30 are disposed along the illumination optical axis 100ax of the light source device 2. The uniform illumination optical system 30 has a first lens array 31, a second lens array 32, a polarization conversion element 33, and a superimposing lens 34.

[0050] The first lens array 31 has a plurality of first lenses 31a for dividing the illumination light WL incident from the optical member 23 into a plurality of partial light beams. The plurality of first lenses 31a are arranged in a matrix in a plane perpendicular to the illumination optical axis 100ax.

[0051] The second lens array 32 has a plurality of second lenses 32a corresponding to the plurality of first lenses 31a of the first lens array 31. The plurality of second lenses 32a are arranged in a matrix in a plane perpendicular to the illumination optical axis 100ax.

[0052] The second lens array 32, together with the superimposing lens 34, forms images of the first lenses 31a of the first lens array 31 near the image forming areas of the light modulation device 4R, the light modulation device 4G, and the light modulation device 4B, respectively.

[0053] The polarization conversion element 33 converts the light emitted from the second lens array 32 into one type of linearly polarized light. The polarization conversion element 33 includes, for example, a polarization separation film and a phase difference plate (not shown).

[0054] The superimposing lens 34 collects the partial light beams emitted from the polarization conversion element 33 and superimposes them near the image forming areas of the light modulation device 4R, the light modulation device 4G, and the light modulation device 4B. The uniform illumination optical system 30 may include a rod lens that makes the illuminance distribution of light uniform.

[0055] As described above, the light source device 2 of this embodiment comprises a first light source 21 that emits blue light E, a light separation optical system 22 that separates the blue light E emitted from the first light source 21 into a first light beam E1 and a second light beam E2 that travel along parallel optical paths, an optical element 23 that passes the first light beam E1 and the second light beam E2 incident from the light separation optical system 22, a focusing optical system 24 that focuses the first light beam E1 and the second light beam E2 that have passed through the optical element 23 and directs them to different positions, and a light scattering element 25 onto which the first light beam E1 and the second light beam E2 emitted from the focusing optical system 24 are incident. The light scattering element 25 has a substrate 250 having a reflecting surface 250a that reflects light, a first wavelength conversion layer 251 that is disposed on the reflecting surface 250a and converts the second light flux E2 incident thereon by the collecting optical system 24 into fluorescence Y of a yellow wavelength band different from the blue wavelength band, and a light scattering layer 252 that is disposed in the X-axis direction along the reflecting surface 250a of the first wavelength conversion layer 251 and scatters the first light flux E1 incident thereon by the collecting optical system 24. The optical member 23 reflects the light that is emitted from the light scattering element 25 and has passed through the collecting optical system 24.

[0056] According to the light source device 2 of the present embodiment, light emitted from the light scattering element 25 arranged in the -Y direction of the optical member 23 and having the light scattering layer 252 and the first wavelength conversion layer 251 can be extracted as illumination light WL by the light collecting optical system 24 and the optical member 23. Therefore, the light emitted from the light scattering layer 252 and the first wavelength conversion layer 251 can be collimated by the common light collecting optical system 24 and guided to the optical member 23. On the other hand, if the light scattering layer and the first wavelength conversion layer are arranged separately in two directions of the optical member 23, the device configuration will become large due to the light collecting optical system being arranged for each of the light scattering layer and the first wavelength conversion layer. According to the optical device 2 of the present embodiment, it is possible to generate white illumination light WL while suppressing an increase in the size of the device configuration.

[0057] The projector 1 of the present embodiment includes the light source device 2 described above, and therefore can realize a small projector that displays color images.

[0058] Second embodiment The light source device of the second embodiment will be described below. The basic configuration of the second embodiment is similar to that of the first embodiment, but the configuration of the light separation optical system is different from that of the first embodiment. Therefore, the configuration of the light separation optical system will be mainly described below, and the same reference numerals will be used to denote components common to the drawings used in the above embodiments, and descriptions thereof will be omitted.

[0059] FIG. 4 is a schematic diagram showing the configuration of a light source device 2A according to the second embodiment. As shown in FIG. 4, the light source device 2A of this embodiment includes a first light source 21, a light separation optical system 112, an optical member 23, a light collection optical system 24, a light scattering element 25, and a uniform illumination optical system 30.

[0060] The light separation optical system 112 of this embodiment separates the blue light E emitted from the first light source 21 into a first light flux E1 and a second light flux E2. The light separation optical system 112 has a first reflecting element 112a and a second reflecting element 112b. The first reflecting element 112a is disposed so as to form an angle of 45 degrees with respect to the optical axis of the blue light E. The second reflecting element 112b is disposed so as to form an angle of 45 degrees with respect to the optical axis of the blue light E, and is disposed in the -X direction of the first reflecting element 112a.

[0061] The first reflecting element 112a is configured with a half mirror that reflects a portion of the blue light E and transmits the remaining portion. The first reflecting element 112a reflects a portion of the blue light E incident from the first light source 21 in the -Y direction as a first light beam E1, and transmits the remaining portion of the blue light E in the -X direction as a second light beam E2.

[0062] The second light flux E2 transmitted through the first reflecting element 112a is incident on the second reflecting element 112b. The second reflecting element 112b is composed of a mirror that reflects the second light flux E2. The second reflecting element 112b reflects the second light flux E2 in the -Y direction. The first light beam E1 and the second light beam E2 thus separated from the blue light E by the light separation optical system 112 travel along optical paths parallel to each other and enter the optical member . In addition, the ratio of the first light beam E1 and the second light beam E2 separated from the blue light E in the light separation optical system 112 can be appropriately changed by adjusting the transmittance of the first reflecting element 112a, etc., depending on the white balance of the illumination light WL generated by the light source device 2A.

[0063] Similarly to the light source device 2 of the first embodiment, the light source device 2A of this embodiment can generate white illumination light WL while preventing the device configuration from becoming large.

[0064] Third embodiment The light source device of the third embodiment will be described below. The basic configuration of the third embodiment is similar to that of the first embodiment, but the configuration of the optical members is different from that of the first embodiment. Therefore, the configuration of the optical members will be mainly described below, and the same reference numerals will be used to denote components common to the drawings used in the above embodiments, and descriptions thereof will be omitted.

[0065] FIG. 5 is a schematic diagram showing a configuration of a light source device 2B according to the third embodiment. As shown in FIG. 5, the light source device 2B of this embodiment includes a first light source 21, a light separation optical system 22, an optical member 230, a light collection optical system 24, a light scattering element 25, and a uniform illumination optical system 30.

[0066] The optical member 230 of this embodiment has a third optical section 233 and a mirror 234 fitted in an opening 233a provided in the third optical section 233. The third optical section 233 is composed of a dielectric multilayer film that transmits the first light beam E1 and the second light beam E2 and reflects the fluorescence Y. The mirror 234 is disposed at a position not overlapping with the optical paths of the first light beam E1 and the second light beam E2, and therefore does not block the first light beam E1 and the second light beam E2 traveling toward the light scattering element 25 side.

[0067] In the optical member 230 of the present embodiment, the mirror 234 reflects the light incident thereon from the light scattering element 25. That is, the mirror 234 reflects the fluorescence Y and the blue scattered light E1s in the +X direction to cause them to enter the uniform illumination optical system 30 as illumination light WL. According to this configuration, the third optical section 233 can be used as a holding member for the mirror 234. Therefore, the number of parts constituting the optical member 230 can be kept small.

[0068] Similarly to the light source device 2A of the first embodiment, the light source device 2B of this embodiment can generate white illumination light WL while preventing the device configuration from becoming large.

[0069] (Fourth embodiment) The light source device of the fourth embodiment will be described below. The configuration of the fourth embodiment differs from that of the second embodiment in that a second light source is further provided, but the other configurations are the same. Therefore, the configuration of the second light source will be mainly described below, and components common to the drawings used in the above embodiments will be given the same reference numerals and will not be described.

[0070] FIG. 6 is a schematic diagram showing the configuration of a light source device 2C according to the fourth embodiment. As shown in FIG. 6, the light source device 2C of this embodiment includes a first light source 21, a second light source 121, a light separation optical system 40, a synthesis mirror 43, an optical element 323, a focusing optical system 24, a light scattering element 25, and a uniform illumination optical system 30.

[0071] The second light source 121 is composed of a semiconductor laser 121a that emits a red light beam made of a laser beam. The red light beam is, for example, a laser beam having a red wavelength band of 610 to 750 nm. The second light source 121 emits red light R made of a red light beam as the second light. In general, red laser light has a weaker output than blue laser light. For this reason, it is desirable to make the number of semiconductor lasers 121a of the second light source 121 greater than the number of semiconductor lasers 21a of the first light source 21. Note that, if the light beam width of the red light R is expanded by increasing the number of semiconductor lasers 121a, the occurrence of color unevenness may be suppressed by reducing the light beam width of the red light R using an afocal optical system and aligning it with the light beam width of the blue light E.

[0072] Combining mirror 43 is disposed so as to form an angle of 45 degrees with respect to the optical axis of second light source 121. Combining mirror 43 reflects red light R incident from second light source 121 in the −X direction and makes it incident on light separation optical system 40.

[0073] The light separation optical system 40 has a first reflecting element 41 and a second reflecting element 42. The first reflecting element 41 is disposed so as to form an angle of 45 degrees with respect to the optical axis of the blue light E. The second reflecting element 42 is disposed so as to form an angle of 45 degrees with respect to the optical axis of the blue light E, and is disposed in the -X direction of the first reflecting element 41.

[0074] The first reflecting element 41 is configured by laminating a half mirror 41a and a dichroic mirror 41b. The half mirror 41a is disposed so as to face the first light source 21, and the dichroic mirror 41b is disposed so as to face the synthesis mirror 43. The half mirror 41a reflects a part of the blue light E and transmits the remaining part. The dichroic mirror 41b has a characteristic of reflecting red light R, which is light in the red wavelength band incident from the synthesis mirror 43, and transmitting other wavelength bands.

[0075] The half mirror 41a of the first reflecting element 41 transmits a portion of the blue light E incident from the first light source 21 in the -X direction as a first light beam E1, and the first light beam E1 transmits through the dichroic mirror 41b. The half mirror 41a of the first reflecting element 41 reflects the remaining portion of the blue light E in the -Y direction as a second light beam E2. The first reflecting element 41 guides the red light R to the optical path of the first light beam E1. The second light beam E2 is emitted from the first reflecting element 41 without being incident on the dichroic mirror 41b. On the other hand, the red light R reflected by the combining mirror 43 is reflected in the −Y direction by the dichroic mirror 41b of the first reflecting element 41, and does not enter the half mirror 41a side.

[0076] In this manner, the first reflecting element 41 reflects the second light beam E2, which is a portion of the blue light E, and the red light R, and transmits the second light beam E2, which is the remaining portion of the blue light E. The second reflecting element 42 is composed of a mirror that reflects the second light flux E2. The second reflecting element 42 reflects the second light flux E2 in the -Y direction.

[0077] The first light beam E1 and the second light beam E2 separated from the blue light E in the light separation optical system 40 in this manner, and the red light R travel along optical paths parallel to each other, and are incident on the optical member 323.

[0078] The optical member 323 has a first optical section 3231 and a second optical section 3232. The first optical section 3231 is configured with a dichroic mirror made of a dielectric multilayer film that transmits blue light E and reflects fluorescence Y. In the case of this embodiment, the first optical section 3231 is not disposed on the optical paths of the first light flux E1 and the red light R.

[0079] The first optical unit 3231 has a property of reflecting the fluorescence Y. Since the red wavelength band is included in the fluorescence Y, which is yellow light, the first optical unit 3231 reflects the red light R. In contrast, in the optical member 323 of this embodiment, the first optical unit 3231 is not disposed on the optical path of the red light R, so that the red light R can be transmitted in the -Y direction. Note that the first optical unit 3231 may have an opening formed at a position where the first light flux E1 and the red light R are incident, and the first light flux E1 and the red light R may be transmitted in the -Y direction.

[0080] The red light R is collected in a defocused state by the collecting optical system 24 and enters the light scattering layer 252 of the light scattering element 25 together with the first light flux E1. The light scattering layer 252 emits red scattered light Rs obtained by scattering the red light R to the collecting optical system 24 together with blue scattered light E1s obtained by scattering the first light flux E1.

[0081] The blue scattered light E1s collimated by the collecting optical system 24 passes through the first optical unit 3231 and is reflected in the +X direction by the second optical unit 3232, and then passes through the first optical unit 3231 again to enter the uniform illumination optical system 30. On the other hand, the red scattered light Rs collimated by the collecting optical system 24 is reflected in the +X direction by the first optical unit 3231 and enters the uniform illumination optical system 30.

[0082] In this manner, the optical member 323 of this embodiment reflects the blue scattered light E1s, the red scattered light Rs and the fluorescent light Y that are emitted from the light scattering element 25, and causes them to enter the uniform illumination optical system 30 as illumination light WL1.

[0083] White light using the fluorescence Y generated by the first wavelength conversion layer 251 made of a yellow phosphor material may have a color lacking in red components. In contrast, the light source device 2C of the present embodiment can obtain white illumination light WL1 containing a sufficient amount of red components by adding red scattered light Rs obtained by scattering the red light R emitted from the second light source 121.

[0084] Fifth embodiment The light source device of the fifth embodiment will be described below. The basic configuration of the fifth embodiment is similar to that of the first embodiment, but the configuration of the light scattering element is different from that of the first embodiment. Therefore, the configuration of the light scattering element will be mainly described below, and the same reference numerals will be used to denote components common to the drawings used in the above embodiments, and descriptions thereof will be omitted.

[0085] FIG. 7 is a schematic diagram showing the configuration of a light source device 2D according to the fifth embodiment. As shown in FIG. 7, a light source device 2D of this embodiment includes a first light source 21, a light separation optical system 112, an optical member 23, a light collection optical system 24, a light scattering element 125, and a uniform illumination optical system 30.

[0086] The light scattering element 125 of this embodiment has a substrate 250, a first wavelength conversion layer 251, a light scattering layer 252, and a second wavelength conversion layer 253. The light incident surface 125a of the light scattering element 125 is the surface of the first wavelength conversion layer 251, the second wavelength conversion layer 253, and the light scattering layer 252 that is opposite to the substrate 250. The first wavelength conversion layer 251 and the second wavelength conversion layer 253 have substantially rectangular shapes and have the same size. The light scattering layer 252 has a substantially rectangular shape and has the same size as the combined size of the first wavelength conversion layer 251 and the second wavelength conversion layer 253.

[0087] Here, the center of the substrate 250C is defined as the center 125C of the light scattering element 125. In this case, the boundary between the first wavelength conversion layer 251 and the light scattering layer 252 is located on the center 125C of the light scattering element 125.

[0088] The second wavelength conversion layer 253 is disposed on the opposite side (-X direction) of the first wavelength conversion layer 251 to the light scattering layer 252. The second wavelength conversion layer 253 receives the second light flux E2 in the blue wavelength band from the light collecting optical system 24 as described below, and converts the second light flux E2 into fluorescence RL in a wavelength band different from the fluorescence Y. The wavelength band of the fluorescence RL in the second wavelength conversion layer 253 has a peak wavelength in the range of, for example, 600 to 800 nm. In other words, the fluorescence RL is red light containing a red light component.

[0089] The second wavelength conversion layer 253 is a layer in which, for example, any one of Pr, Eu, and Cr is dispersed as an activator (Y 1-x ,Gd x )3(Al,Ga)5O 12 The YAG phosphor (any of Pr:YAG, Eu:YAG, and Cr:YAG) is used. The activator may contain one selected from Pr, Eu, and Cr, or may be a co-activator containing multiple elements selected from Pr, Eu, and Cr.

[0090] The light collecting optical system 24 of this embodiment collects the first light flux E1 and the second light flux E2 and guides them to different positions on the light incident surface 125a of the light scattering element 125. Specifically, the light collecting optical system 24 causes the first light flux E1 and the second light flux E2 to be incident on the light scattering element 125 so that the first light flux E1 is incident on the light scattering layer 252 and the second light flux E2 straddles the boundary between the first wavelength conversion layer 251 and the second wavelength conversion layer 253. In other words, the second light flux E2 can excite the first wavelength conversion layer 251 and the second wavelength conversion layer 253 without splitting the second light flux E2 into two light fluxes. Therefore, there is no need to change the configuration of the light separation optical system 112.

[0091] In this embodiment, the first wavelength conversion layer 251 emits fluorescence Y obtained by wavelength-converting the second luminous flux E2 in all directions at a wide radiation angle by Lambertian emission, and the second wavelength conversion layer 253 emits fluorescence RL obtained by wavelength-converting the second luminous flux E2 in all directions at a wide radiation angle by Lambertian emission.

[0092] 7, the light collecting optical system 24 and the light scattering element 125 are arranged such that the optical axis 24AX is shifted in the -X direction with respect to the center 125C of the light scattering element 125. In other words, the optical axis 24AX of the light collecting optical system 24 is located closer to the first wavelength conversion layer 251 than the center 125C of the light scattering element 125. Therefore, the emission center of the fluorescence Y, RL approaches the optical axis 24AX of the light collecting optical system 24, so that the light collecting optical system 24 can efficiently capture the fluorescence Y, RL emitted at a wide radiation angle by Lambertian emission. The fluorescence Y, RL is approximately parallelized by the light collecting optical system 24 and travels along the optical axis 24AX to enter the optical member 23.

[0093] Here, the wavelength band of the fluorescence RL partially overlaps with that of the fluorescence Y in the yellow wavelength band. For this reason, the first optical unit 231 of the optical member 23 in this embodiment has the property of reflecting the fluorescence RL in the red wavelength band. As a result, the fluorescence Y, RL collimated by the focusing optical system 24 is reflected in the +X direction by the first optical unit 231 and enters the uniform illumination optical system 30. Note that the blue scattered light E1s collimated by the focusing optical system 24 passes through the first optical unit 231 and is reflected in the +X direction by the second optical unit 232, and passes through the first optical unit 231 again to enter the uniform illumination optical system 30.

[0094] In the light source device 2D of the present embodiment, the optical member 23 reflects the blue scattered light E1s, the fluorescence RL and the fluorescence Y which are light emitted from the light scattering element 125, and makes them enter the uniform illumination optical system 30 as illumination light WL2.

[0095] According to the light source device 2D of this embodiment, by adding the red fluorescence RL emitted from the second wavelength conversion layer 253, it is possible to obtain white illumination light WL2 containing a sufficient amount of red components.

[0096] Sixth embodiment The light source device of the sixth embodiment will be described below. The configuration of the sixth embodiment is similar to that of the first embodiment, but the configurations of the light scattering element and the light separation optical system are different from those of the first embodiment. Therefore, the configurations of the light scattering element and the light separation optical system will be mainly described below, and the same reference numerals will be used to designate the same components as those in the drawings used in the above embodiments, and the description thereof will be omitted.

[0097] FIG. 8 is a schematic configuration diagram showing a light source device 2E according to the sixth embodiment. As shown in FIG. 8, a light source device 2E of this embodiment includes a first light source 21, a light separation optical system 122, an optical member 23, a light collection optical system 24, a light scattering element 50, and a uniform illumination optical system 30.

[0098] Fig. 9 is a plan view showing the configuration of a light scattering element 50 of this embodiment. As shown in Fig. 9, the light scattering element 50 of this embodiment has a substrate 250, a first wavelength conversion layer 351, a light scattering layer 352, and a second wavelength conversion layer 353. The light incident surface 50a of the light scattering element 50 is the surface of the first wavelength conversion layer 351, the second wavelength conversion layer 353, and the light scattering layer 352 opposite to the substrate 250. In other words, the light scattering element 50 of this embodiment has a different layout of the wavelength conversion layers and the light scattering layer from the light scattering element 125 of the fifth embodiment.

[0099] The first wavelength conversion layer 351 and the light scattering layer 352 have an approximately square outer shape and are of the same size. The first wavelength conversion layer 351 and the light scattering layer 352 are aligned on the substrate 250 in the X direction.

[0100] The second wavelength conversion layer 253 is disposed in the +Y direction, which is a second direction intersecting the first direction (+X direction) along the reflective surface 250a of the first wavelength conversion layer 251. The second wavelength conversion layer 253 has a substantially rectangular outer shape and has a size equivalent to the combined size of the first wavelength conversion layer 351 and the light scattering layer 352. In other words, the first wavelength conversion layer 351, the light scattering layer 352, and the second wavelength conversion layer 353 as a whole form a substantially square outer shape.

[0101] The light separation optical system 122 of this embodiment has a first reflecting element 22a, a second reflecting element 22b, and a beam separation unit 27. In the light separation optical system 122, a component of the blue light E reflected in the -Y direction by the first reflecting element 22a enters the optical member 23 as a first beam E1. Also, a component of the blue light E transmitted through the first reflecting element 22a in the -X direction enters the beam separation unit 27. The beam separation unit 27 separates a part of the blue light E as a third beam E3 that travels along an optical path parallel to the first beam E1 and the second beam E2.

[0102] The light beam separator 27 includes a third reflecting element 27a and a fourth reflecting element 27b. The third reflecting element 27a is disposed in the XZ plane so as to form an angle of 45 degrees with the X-axis and the Z-axis. The third reflecting element 27a is configured with a half mirror, and reflects a part of the blue light E transmitted through the first reflecting element 22a in the second direction, that is, the -Z direction, as a third light flux E3, and transmits the other part of the blue light E in the -X direction as a second light flux E2.

[0103] The fourth reflecting element 27b is composed of a mirror that reflects the third light flux E3 incident from the third reflecting element 27a toward the optical member 23. The fourth reflecting element 27b is disposed in the YZ plane so as to form an angle of 45 degrees with the Y axis and the Z axis, and reflects the third light flux E3 in the -Y direction.

[0104] The first light beam E1, the second light beam E2, and the third light beam E3 thus separated from the blue light E by the light separation optical system 122 travel along optical paths parallel to each other, and enter the optical member .

[0105] The light-collecting optical system 24 collects the first light flux E1, the second light flux E2, and the third light flux E3 and guides them to different positions on the light incident surface 50a of the light scattering element 50. As shown in Fig. 9, the light-collecting optical system 24 causes the first light flux E1 to be incident on the light scattering layer 352 of the light scattering element 50, the second light flux E2 to be incident on the first wavelength conversion layer 351 of the light scattering element 50, and the third light flux E3 to be incident on the second wavelength conversion layer 353 of the light scattering element 50. That is, the light-collecting optical system 24 of this embodiment causes the third light flux E3 reflected by the fourth reflecting element 27b and transmitted through the optical member 23 to be incident on the second wavelength conversion layer 353. The behavior of the fluorescent light Y, RL and blue scattered light E1s generated by the light scattering element 50 is similar to that of the light scattering element 125 of the fifth embodiment, and therefore description thereof will be omitted.

[0106] According to the light source device 2E of this embodiment, by adding the red fluorescence RL emitted from the second wavelength conversion layer 353, it is possible to obtain white illumination light WL2 containing a sufficient amount of red components.

[0107] Seventh embodiment The light source device of the seventh embodiment will be described below. The basic configuration of the seventh embodiment is similar to that of the first embodiment, but the configurations of the light source unit and the light scattering element are different from those of the first embodiment. Therefore, the configurations of the light source unit and the light scattering element will be mainly described below, and the same reference numerals will be used to designate the same components as those in the drawings used in the above embodiments, and the description thereof will be omitted.

[0108] FIG. 10 is a schematic diagram showing the configuration of a light source device 2F according to the seventh embodiment. As shown in FIG. 10, a light source device 2F of this embodiment includes a first light source 20A, a second light source 20B, an optical member 23, a light collecting optical system 24, a light scattering element 60, and a uniform illumination optical system 30.

[0109] The first light source 20A of the present embodiment is composed of a semiconductor laser 20a that emits laser light having a blue wavelength band of, for example, 440 to 490 nm. Therefore, the first light source 20A emits blue light B1, which is the first light made of coherent light.

[0110] On the other hand, the second light source 20B of the present embodiment is composed of LED elements 20b that emit light in the same blue wavelength band as the first light source 20A. That is, the second light source 20B emits blue light B2, which is the second light consisting of non-coherent light.

[0111] The first light source 20A and the second light source 20B are disposed so that their optical axes are aligned in the Y direction. That is, the blue lights B1 and B2 emitted from the first light source 20A and the second light source 20B are incident on the optical member 23 parallel to each other. The optical member 23 passes the blue lights B1 and B2. Note that "parallel" only requires that the optical path of the first light and the optical path of the second light are aligned, and includes cases where the optical paths form an angle on the extension lines of each other's optical paths.

[0112] The light collecting optical system 24 collects the blue light beams B1 and B2 transmitted through the optical member 23 and guides them to different positions on the light scattering element 60. The blue light beams B1 and B2 are incident on different regions of a convex lens 24a that constitutes the light collecting optical system 24. The blue light beams B1 and B2 are incident on regions of the convex lens 24a that are at different distances from the optical axis 24AX in the radial direction of the convex lens 24a.

[0113] The light scattering element 60 has a substrate 250, a first wavelength conversion layer 451, and a light scattering layer 452. The light incident surface 60a of the light scattering element 60 is the surface of the first wavelength conversion layer 451 and the light scattering layer 452 opposite to the substrate 250. The light scattering layer 452 is disposed in the +X direction, which is a first direction along the reflective surface 250a of the first wavelength conversion layer 451.

[0114] The light-collecting optical system 24 causes the blue light B2 to be incident on the light scattering layer 452 of the light scattering element 60, and causes the blue light B1 to be incident on the first wavelength conversion layer 451 of the light scattering element 60. The light scattering layer 452 scatters the blue light B2 and emits blue scattered light B2s toward the light-collecting optical system 24, and the first wavelength conversion layer 451 emits the fluorescence Y toward the light-collecting optical system 24.

[0115] The first wavelength conversion layer 451 emits the third light, fluorescence Y, having a wavelength band different from the wavelength bands of blue light B and blue light B2, in all directions at a wide radiation angle by Lambertian emission. In other words, the fluorescence Y has a wide angular distribution. The present inventors have noticed that when a phosphor is excited to generate fluorescence, if coherent light and non-coherent light are used as excitation light, a difference occurs in the angular distribution of the generated fluorescence.

[0116] In the light source device 2F of the present embodiment, blue light B1 consisting of laser light, which is coherent light, is incident as excitation light on the first wavelength conversion layer 451. Here, when blue light B2, which is non-coherent light, is incident as excitation light on the first wavelength conversion layer 451, the degree of scattering of the fluorescence Y becomes greater than when blue light B1 is used as the excitation light. In other words, when blue light B2 is incident on the first wavelength conversion layer 451, the angular distribution of the fluorescence Y becomes wider, and the fluorescence Y cannot be efficiently absorbed by the focusing optical system 24, which may reduce the light utilization efficiency.

[0117] In contrast, in the light source device 2F of the present embodiment, as described above, blue light B1 made of laser light is made incident on the first wavelength conversion layer 451 as excitation light, thereby further reducing the angular distribution of the fluorescence Y. This reduces the spread of the angular distribution of the fluorescence Y, so that the light collecting optical system 24 can efficiently capture the fluorescence Y and efficiently use the fluorescence Y as the illumination light WL.

[0118] Furthermore, in the light source device 2F of the present embodiment, the degree of light scattering of the light scattering layer 452 is adjusted so that the angular distribution of the fluorescence Y emitted from the first wavelength conversion layer 451 and the angular distribution of the blue scattered light B2s of the blue light B2 emitted from the light scattering layer 452 are made closer to each other.

[0119] When the angular distribution of the blue scattered light B2s is made closer to that of the fluorescence Y, which has a large angular distribution, it becomes necessary to increase the degree of scattering of the light scattering layer 452.

[0120] The present inventors have noticed that non-coherent light is easier to scatter than coherent light. In the light source device 2F of this embodiment, blue light B1 made of laser light is used as excitation light to suppress the angular distribution of fluorescence Y, while blue light B2, which is non-coherent light and is easier to scatter than laser light, is made to enter the light scattering layer 452. Therefore, according to the light source device 2F of this embodiment, it is possible to further reduce the degree of scattering of the light scattering layer 452, and therefore the manufacturing cost of the light scattering layer 452 can be reduced.

[0121] The optical member 23 reflects the fluorescent light Y and the blue scattered light E1s, which are light emitted from the light scattering element 60, in the +X direction and causes them to enter the uniform illumination optical system 30, similar to the above-described embodiment.

[0122] According to the light source device 2F of the present embodiment, by making appropriate blue light B1, B2 incident on the light scattering layer 452 and the first wavelength conversion layer 451 of the light scattering element 60, it is possible to reduce the cost of the light scattering element 60 while suppressing the spread of the angular distribution of the fluorescence Y.

[0123] Eighth embodiment The light source device of the eighth embodiment will be described below. The basic configuration of the eighth embodiment is similar to that of the first embodiment, but the configuration of the light scattering element is different from that of the first embodiment. Therefore, the configuration of the light scattering element will be mainly described below, and the same reference numerals will be used to denote components common to the drawings used in the above embodiments, and descriptions thereof will be omitted.

[0124] FIG. 11 is a schematic diagram showing the configuration of a light source device 2G according to the eighth embodiment. As shown in FIG. 11, a light source device 2G of this embodiment includes a first light source 21, a light separation optical system 22, an optical member 23, a light collection optical system 24, a light scattering element 25G, and a uniform illumination optical system 30.

[0125] The light scattering element 25G of this embodiment includes a disk 550, a first wavelength conversion layer 551, a light scattering layer 552, and a motor M. The first wavelength conversion layer 551 is arranged in a ring shape in the circumferential direction of the disk 550. The light scattering layer 552 is arranged in a ring shape in the circumferential direction of the disk 550. The first wavelength conversion layer 551 and the light scattering layer 552 are arranged side by side in the radial direction of the disk 550, and the light scattering layer 552 is located radially inward of the first wavelength conversion layer 551. The motor M rotates the disk 550 around a rotation axis O passing through the center of the disk 550.

[0126] In other words, the light scattering element 25G of this embodiment is configured as a rotational light scattering element in which the incident positions of the first light beam E1 and the second light beam E2 relative to the first wavelength conversion layer 551 and the light scattering layer 552 change over time as the circular plate 550 rotates.

[0127] According to the light source device 2G of this embodiment, when using a rotational light scattering element 25G, it is possible to generate white illumination light WL while suppressing an increase in the size of the device configuration, similarly to the light source device 2 of the first embodiment.

[0128] In the above embodiment, the configuration of the light source device applied to a three-plate type projector equipped with the light modulation devices 4R, 4G, and 4B is given as an example, but the light source device of the present invention can also be applied to a single-plate type projector using one light modulation device. Furthermore, the light modulation device is not limited to the above-mentioned liquid crystal panel, and for example, a digital mirror device can also be used.

[0129] The following describes a configuration according to a modified example in which the light source device 2G of this embodiment is applied to a single-panel projector. 12 is a schematic diagram showing a light source device 2H according to a modified example. Note that the same components as those in the eighth embodiment are given the same reference numerals, and the description thereof will be omitted. 12, the light source device 2H of this modification includes a first light source 21, a light separation optical system 22, an optical member 23, a light collecting optical system 24, a light scattering element 25H, a reflecting mirror 26, and a uniform illumination optical system 30. In the light source device 2H of this modification, the white illumination light WL emitted from the light separation optical system 22 is reflected by the reflecting mirror 26 toward the light scattering element 25H. The light scattering element 25H emits red light, green light, or blue light in a time-sequential manner, as described later. The uniform illumination optical system 30 is disposed on the optical path of the red light, green light, or blue light emitted from the light scattering element 25H.

[0130] The light scattering element 25H of this embodiment includes a disk 650, a first wavelength conversion layer 551, a light scattering layer 552, and a motor M. The first wavelength conversion layer 551 is arranged in a ring shape in the circumferential direction of the disk 650. The light scattering layer 552 is arranged in a ring shape in the circumferential direction of the disk 650. The first wavelength conversion layer 551 and the light scattering layer 552 are arranged side by side in the radial direction of the disk 650, and the light scattering layer 552 is located radially inward of the first wavelength conversion layer 551. The motor M rotates the disk 550 around a rotation axis O passing through the center of the disk 650.

[0131] The disk 650 has a color wheel section 651 provided inside the light scattering layer 552. The illumination light WL reflected by the reflecting mirror 26 is incident on the color wheel section 651. The color wheel section 651 includes a red filter 651R, a green filter 651G, and a blue filter 651B arranged along the circumferential direction. The red filter 651R transmits the red component of the illumination light WL incident from the reflecting mirror 26, the green filter 651G transmits the green component of the illumination light WL incident from the reflecting mirror 26, and the blue filter 651B transmits the blue component of the illumination light WL incident from the reflecting mirror 26.

[0132] In this way, the light source device 2H of this modification can emit red light R, green light G, and blue light B in a time-sequential manner in the -Y direction from the white illumination light WL by the color wheel portion 651 of the light scattering element 25H. Therefore, a single-panel projector configuration can be realized by driving one light modulation device in synchronization with the red light R, green light G, and blue light B that are incident in a time-sequential manner from the light source device 2H.

[0133] 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.

[0134] For example, in the light source device 2E of the sixth embodiment, a part of the blue light E is separated as the third light beam E3 using the light beam separation section 27 and made incident on the second wavelength conversion layer 353 of the light scattering element 50. However, the fluorescence RL may be generated by making the second light beam E2 incident on the boundary between the first wavelength conversion layer 351 and the second wavelength conversion layer 353 without using the light beam separation section 27. Also, the fluorescence RL may be generated by making the first light beam E1 incident on the boundary between the light scattering layer 352 and the second wavelength conversion layer 353.

[0135] In addition, the specific description of the shape, number, arrangement, material, etc. of each component of the light source 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 light source 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 light source 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 have only one light modulation device.

[0136] In the above embodiment, the light source device of the present invention is applied to a projector, but the present invention is not limited to this. The light source device of the present invention can also be applied to lighting fixtures, automobile headlights, and the like.

[0137] [Summary of this disclosure] The following is a summary of this disclosure. (Appendix 1) a first light source that emits a first light; a light separation optical system that separates the first light emitted from the first light source into a first light beam and a second light beam traveling along optical paths parallel to each other; an optical member that transmits the first light beam and the second light beam incident from the light separation optical system; a focusing optical system that focuses each of the first light flux and the second light flux that have passed through the optical member; a light scattering element onto which the first light flux and the second light flux emitted from the light collecting optical system are incident at different positions, the light scattering element includes a substrate having a reflective surface that reflects light, a first wavelength conversion layer that is disposed on the reflective surface and that converts the second light flux incident by the focusing optical system into a second light having a wavelength band different from the wavelength band of the first light, and a light scattering layer that is disposed in a first direction along the reflective surface of the first wavelength conversion layer and that scatters the first light flux incident by the focusing optical system, The optical member reflects the light emitted from the light scattering element and passing through the light collecting optical system. Light source device.

[0138] According to the configuration of Supplementary Note 1, the light emitted from the light scattering element arranged on one side of the optical member and having the light scattering layer and the first wavelength conversion layer can be extracted by the light collecting optical system and the optical member. Therefore, the light emitted from the light scattering layer and the first wavelength conversion layer can be collimated by a common light collecting optical system and guided to the optical member. On the other hand, if the light scattering layer and the first wavelength conversion layer are arranged separately on two sides of the optical member, the device configuration will become large by arranging the light collecting optical system for each of the light scattering layer and the first wavelength conversion layer. According to this configuration, it is possible to generate desired light while suppressing the increase in size of the device configuration.

[0139] (Appendix 2) The optical member is a first optical unit that transmits the first light flux and the second light flux and reflects the second light; and a second optical unit that guides the scattered light of the first light flux that is emitted from the light scattering layer of the light scattering element and passes through the first optical unit to an optical path of the second light reflected by the first optical unit. 2. A light source device as described in claim 1.

[0140] According to the configuration of Supplementary Note 2, the optical paths of the scattered light of the first light flux and the second light are aligned, thereby making it possible to suppress the occurrence of color unevenness.

[0141] (Appendix 3) The light separation optical system includes: a first reflecting element that transmits a portion of the first light emitted from the first light source as the first light flux and reflects another portion of the first light as the second light flux; a second reflecting element that reflects the second light flux reflected by the first reflecting element toward the optical member; 3. A light source device according to claim 1 or 2.

[0142] According to the configuration of Supplementary Note 3, it is possible to realize a configuration in which the first light emitted from the first light source is separated into a first light beam and a second light beam.

[0143] (Appendix 4) The light separation optical system includes: a first reflecting element that reflects a portion of the first light emitted from the first light source as the first light flux and transmits another portion of the first light as the second light flux; a second reflecting element that reflects the second light flux transmitted through the first reflecting element toward the optical member; 4. A light source device according to claim 1.

[0144] According to the configuration of Supplementary Note 4, it is possible to realize a configuration in which the first light emitted from the first light source is separated into a first light beam and a second light beam.

[0145] (Appendix 5) a second light source that emits a third light having a wavelength band different from the first light and the second light, the first reflecting element directs the third light to an optical path of the first light beam; 5. A light source device according to claim 3 or 4.

[0146] According to the configuration of Supplementary Note 5, by adding the scattered light of the third light emitted from the second light source to the scattered light of the first light and the second light, it is possible to generate illumination light of a desired color.

[0147] (Appendix 6) the focusing optical system includes a convex lens having a positive power; the first light beam and the second light beam are incident on different regions of the convex lens; 6. A light source device according to any one of claims 1 to 5.

[0148] According to the configuration of Supplementary Note 6, it is possible to simplify the configuration of the light collecting optical system and to guide the first light flux and the second light flux to different positions on the light scattering element.

[0149] (Appendix 7) a distance along the optical axis of the focusing optical system between the principal point of the focusing optical system and the light incidence surface of the light scattering element is different from a focal length of the focusing optical system; 7. A light source device according to any one of claims 1 to 6.

[0150] According to the configuration of Supplementary Note 7, the light collecting optical system can be disposed with respect to the light scattering element so that the first light flux and the second light flux are incident in a defocused state on the light incident surface of the light scattering element.

[0151] (Appendix 8) The distance is shorter than the focal length of the focusing optics. 8. The light source device according to claim 7.

[0152] According to the configuration of Supplementary Note 8, the distance between the light collecting optical system and the light scattering element can be reduced. Therefore, the outer diameter of the light collecting optical system can be reduced, and the light emitted from the light scattering element can be efficiently taken in.

[0153] (Appendix 9) the optical member includes a first region on which the first light flux is incident, and a second region on which the second light flux is incident, the second region being located on an opposite side to the first region with respect to a center of the optical member, The first region and the second region are disposed on either side of the optical axis of the focusing optical system. 9. A light source device according to any one of claims 1 to 8.

[0154] If the first region and the second region were arranged on one side of the optical axis, the outer diameter of the focusing optical system would be large. According to the configuration of Supplementary Note 9, the focusing optical system can efficiently capture the first light flux and the second light flux, so that the outer diameter of the focusing optical system can be prevented from being large.

[0155] (Appendix 10) a first distance in a direction intersecting the optical axis between a first position, which is an incident position of the second light flux on the light scattering element, and a second position, which is an intersection point of the optical axis of the light collecting optical system and the light scattering element, is shorter than a second distance in a direction intersecting the optical axis between a third position, which is an incident position of the first light flux on the light scattering element, and the second position. 10. A light source device according to any one of claims 1 to 9.

[0156] According to the configuration of Supplementary Note 10, while the optical axis is positioned on the first wavelength conversion layer, the second light flux can be incident at a position closer to the optical axis. In other words, since the emission center of the second light approaches the optical axis of the focusing optical system, the focusing optical system can efficiently capture the second light emitted at a wide radiation angle.

[0157] (Appendix 11) The light scattering element further includes a second wavelength conversion layer that converts the second light flux into a third light having a wavelength band different from that of the first light and the second light. 11. A light source device according to any one of claims 1 to 10.

[0158] According to the configuration of Supplementary Note 11, by adding the third light to the scattered light of the first light and the second light, illumination light of a desired color can be generated.

[0159] (Appendix 12) the second wavelength conversion layer is disposed in a second direction intersecting the first direction of the first wavelength conversion layer; the light separation optical system further includes a light beam separation unit that separates a part of the first light into a third light beam traveling along an optical path parallel to the first light beam and the second light beam, the light beam splitting unit includes a third reflecting element that reflects a portion of the first light as the third light beam in the second direction and transmits another portion of the first light as the second light beam, and a fourth reflecting element that reflects the third light beam incident from the third reflecting element toward the optical member, the light-collecting optical system causes the third light flux reflected by the fourth reflecting element and passing through the optical member to be incident on the second wavelength conversion layer; 12. A light source device according to any one of claims 1 to 11.

[0160] According to the configuration of Supplementary Note 12, a configuration can be realized in which the third light flux separated from the first light is incident on a second wavelength conversion layer arranged in the second direction of the first wavelength conversion layer to generate the second light.

[0161] (Appendix 13) the second wavelength conversion layer is disposed on the side of the first wavelength conversion layer opposite the light scattering layer; the focusing optical system causes the second light flux to be incident on the light scattering element such that the second light flux straddles a boundary between the first wavelength conversion layer and the second wavelength conversion layer; 13. A light source device according to any one of claims 1 to 12.

[0162] According to the configuration of Addendum 13, a configuration can be realized in which a third light flux separated from the first light is incident on a second wavelength conversion layer arranged on the opposite side of the first wavelength conversion layer to the light scattering layer to generate a second light.

[0163] (Appendix 14) a first light source that emits a first light composed of coherent light; a second light source that emits a second light consisting of incoherent light; an optical member that transmits the first light and the second light that are incident parallel to each other; a focusing optical system that focuses the first light and the second light that have passed through the optical member; a light scattering element into which the first light and the second light emitted from the light collecting optical system are incident at different positions, the light scattering element includes a substrate having a reflecting surface that reflects light, a first wavelength conversion layer that is disposed on the reflecting surface and that converts the first light incident by the focusing optical system and the second light into a third light having a wavelength band different from the wavelength band of the first light and the second light, and a light scattering layer that is disposed in a direction along the reflecting surface of the first wavelength conversion layer and that scatters the second light incident by the focusing optical system; the optical member reflects the light emitted from the light scattering element and passing through the light collecting optical system; a degree of light scattering of the light scattering layer is adjusted so that an angular distribution of the third light emitted from the first wavelength conversion layer and an angular distribution of the scattered light of the second light emitted from the light scattering layer are made closer to each other. Light source device.

[0164] According to the configuration of Appendix 14, by making the first light and the second light incident on the light scattering layer and the first wavelength conversion layer of the light scattering element in an appropriate combination, it is possible to reduce the cost of the light scattering element while suppressing the spread of the second angular distribution.

[0165] (Appendix 15) A light source device according to any one of claims 1 to 14, a light modulation device that modulates the illumination light emitted from the light source device based on image information; a projection optical device that projects the image light modulated by the light modulation device. projector.

[0166] According to the configuration of Supplementary Note 15, a small projector can be realized. [Explanation of symbols]

[0167] 1...projector, 2...optical device, 2, 2A, 2B, 2C, 2D, 2E, 2F, 2G, 2H...light source device, 4B, 4G, 4R...light modulation device, 6...projection optical device, 20A, 21...first light source, 20B, 121...second light source, 22, 40, 112, 122...light separation optical system, 22a, 41, 112a...first reflection element, 22b, 42, 112b...second reflection element, 23, 230, 323...optical member, 23A...first region, 23B...second region, 24...light-collecting optical system, 24a...convex lens, 24AX...optical axis (of the light-collecting optical system), 24C...principal point, 25, 25G, 25H, 50, 60, 125...light scattering element, 25a , 50a, 60a, 125a...light incident surface, 27...light beam separation section, 27a...third reflective element, 27b...fourth reflective element, 231, 3231...first optical section, 232, 3232...second optical section, 250, 250C...substrate, 250a...reflective surface, 251, 351, 451, 551...first wavelength conversion layer, 252, 352, 452, 552...light scattering layer, 253, 353...second wavelength conversion layer, D1...first distance, D2...second distance, E1...first light beam, E2...second light beam, E3...third light beam, F...focal length, P1...first position, P2...second position, P3...third position, RL, Y...fluorescence (third light), WL, WL1, WL2...illumination light.

Claims

1. A first light source that emits a first light; a light separation optical system that separates the first light emitted from the first light source into a first light beam and a second light beam traveling along optical paths parallel to each other; an optical member that transmits the first light beam and the second light beam incident from the light separation optical system; a focusing optical system that focuses each of the first light flux and the second light flux that have passed through the optical member; a light scattering element onto which the first light flux and the second light flux emitted from the light collecting optical system are incident at different positions, the light scattering element includes a substrate having a reflective surface that reflects light, a first wavelength conversion layer that is disposed on the reflective surface and that converts the second light flux incident by the focusing optical system into a second light having a wavelength band different from the wavelength band of the first light, and a light scattering layer that is disposed in a first direction along the reflective surface of the first wavelength conversion layer and that scatters the first light flux incident by the focusing optical system, The optical member reflects the light emitted from the light scattering element and passing through the light collecting optical system. Light source device.

2. The optical member is a first optical unit that transmits the first light flux and the second light flux and reflects the second light; and a second optical unit that guides the scattered light of the first light flux that is emitted from the light scattering layer of the light scattering element and passes through the first optical unit to an optical path of the second light reflected by the first optical unit. The light source device according to claim 1 .

3. The light separation optical system includes: a first reflecting element that transmits a portion of the first light emitted from the first light source as the first light flux and reflects another portion of the first light as the second light flux; a second reflecting element that reflects the second light flux reflected by the first reflecting element toward the optical member; The light source device according to claim 1 or 2.

4. The light separation optical system includes: a first reflecting element that reflects a portion of the first light emitted from the first light source as the first light flux and transmits another portion of the first light as the second light flux; a second reflecting element that reflects the second light flux transmitted through the first reflecting element toward the optical member; The light source device according to claim 1 or 2.

5. a second light source that emits a third light having a wavelength band different from the first light and the second light, The first reflecting element guides the third light to an optical path of the first light beam. The light source device according to claim 3 .

6. the focusing optical system includes a convex lens having a positive power; the first light beam and the second light beam are incident on different regions of the convex lens; The light source device according to claim 1 or 2.

7. a distance along the optical axis of the focusing optical system between the principal point of the focusing optical system and the light incidence surface of the light scattering element is different from a focal length of the focusing optical system; The light source device according to claim 1 or 2.

8. The distance is shorter than the focal length of the focusing optics. The light source device according to claim 7.

9. the optical member includes a first region on which the first light flux is incident, and a second region on which the second light flux is incident, the second region being located on an opposite side to the first region with respect to a center of the optical member, The first region and the second region are disposed on either side of the optical axis of the focusing optical system. The light source device according to claim 1 or 2.

10. a first distance in a direction intersecting the optical axis between a first position, which is an incident position of the second light flux on the light scattering element, and a second position, which is an intersection point between the optical axis of the light collecting optical system and the light scattering element, is shorter than a second distance in a direction intersecting the optical axis between a third position, which is an incident position of the first light flux on the light scattering element, and the second position; The light source device according to claim 1 or 2.

11. The light scattering element further includes a second wavelength conversion layer that converts the second light flux into a third light having a wavelength band different from that of the first light and the second light. The light source device according to claim 1 or 2.

12. the second wavelength conversion layer is disposed in a second direction intersecting the first direction of the first wavelength conversion layer; the light separation optical system further includes a light beam separation unit that separates a portion of the first light into a third light beam traveling along an optical path parallel to the first light beam and the second light beam, the light beam splitting unit includes a third reflecting element that reflects a portion of the first light in the second direction as the third light beam and transmits another portion of the first light as the second light beam, and a fourth reflecting element that reflects the third light beam incident from the third reflecting element toward the optical member, the light-collecting optical system causes the third light flux reflected by the fourth reflecting element and passing through the optical member to be incident on the second wavelength conversion layer; The light source device according to claim 11.

13. the second wavelength conversion layer is disposed on the side of the first wavelength conversion layer opposite the light scattering layer; the focusing optical system causes the second light flux to be incident on the light scattering element such that the second light flux straddles a boundary between the first wavelength conversion layer and the second wavelength conversion layer; The light source device according to claim 11.

14. a first light source that emits a first light composed of coherent light; a second light source that emits a second light consisting of incoherent light; an optical member that transmits the first light and the second light that are incident parallel to each other; a focusing optical system that focuses the first light and the second light that have passed through the optical member; a light scattering element into which the first light and the second light emitted from the light collecting optical system are incident at different positions, the light scattering element includes a substrate having a reflecting surface that reflects light, a first wavelength conversion layer that is disposed on the reflecting surface and that converts the first light incident by the focusing optical system and the second light into a third light having a wavelength band different from the wavelength band of the first light and the second light, and a light scattering layer that is disposed in a direction along the reflecting surface of the first wavelength conversion layer and that scatters the second light incident by the focusing optical system; the optical member reflects the light emitted from the light scattering element and passing through the light collecting optical system; a degree of light scattering of the light scattering layer is adjusted so that an angular distribution of the third light emitted from the first wavelength conversion layer and an angular distribution of the scattered light of the second light emitted from the light scattering layer are made closer to each other; Light source device.

15. The light source device according to claim 1 or 2, a light modulation device that modulates the illumination light emitted from the light source device based on image information; a projection optical device that projects the image light modulated by the light modulation device. projector.

Images