Light source device and projector

Abstract

To provide a light source device and a projector capable of miniaturizing a device configuration.SOLUTION: A light source device according to the present disclosure includes a light source configured to emit first light having a first wavelength band, a diffusion element which the first light emitted from the light source enters, an optical element which the first light having passed through the diffusion element enters, a light collection optical system which the first light having passed through the optical element enters, a wavelength conversion element configured to convert a part of the first light into second light having a second wavelength band different from the first wavelength band, and a reflecting optical system configured to reflect another part of the first light emitted from the wavelength conversion element. The wavelength conversion element has the wavelength conversion layer having the plane of incidence of light which the first light enters, and the second reflecting film which is disposed on the plane of incidence of light, and separates the first light into the one part and the other part, and the other part of the first light separated by the second reflecting film enters the diffusion element.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] Conventionally, a light source device has been proposed that separates blue light emitted from a light source, and emits white light by combining yellow fluorescence generated by making some of the separated blue light incident on a phosphor, with blue light obtained by diffusing the remaining part of the separated blue light (see, for example, Patent Document 1 below). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-13764 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the above light source device, the optical path of some of the blue light heading toward the phosphor is different from the optical path of the other part of the blue light heading toward the diffuser plate, which necessitates the placement of optical components in each optical path, resulting in an increase in the size of the device configuration. [Means for solving the problem]

[0005] In order to solve the above problem, according to a first aspect of the present invention, there is provided a light source device comprising: a light source that emits first light in a first wavelength band; a diffusion element onto which the first light emitted from the light source is incident; an optical element onto which the first light that has passed through the diffusion element is incident; a focusing optical system onto which the first light that has passed through the optical element is incident; a wavelength conversion element that converts a portion of the first light into second light in a second wavelength band different from the first wavelength band; and a reflection optical system that reflects another portion of the first light emitted from the wavelength conversion element, wherein the optical element has a first reflection film that transmits the first light and reflects the second light, and the wavelength conversion element has a wavelength conversion layer having a first surface onto which the first light is incident, and a second reflection film provided on the first surface that separates the first light into the first portion and the other portion, and the other portion of the first light separated by the second reflection film is incident on the diffusion element.

[0006] According to a second aspect of the present invention, there is provided a light source device comprising: a light source that emits first light having a first wavelength band; a diffusion element that transmits the first light emitted from the light source; a reflective optical system that reflects the first light that has passed through the diffusing element; an optical element onto which the first light reflected by the reflective optical system is incident; a focusing optical system onto which the first light that has passed through the optical element is incident; and a wavelength conversion element that converts a portion of the first light into second light of a second wavelength band different from the first wavelength band, wherein the optical element has a first reflective film that transmits the first light and reflects the second light, and the wavelength conversion element has a wavelength conversion layer having a first surface onto which the first light is incident, and a second reflective film provided on the first surface that separates the first light into the first portion and another portion, and the other portion of the first light separated by the second reflective film is incident on the diffusion element.

[0007] According to a third aspect of the present invention, there is provided a projector comprising a light source device of the first or second aspect, a light modulation device that modulates light incident from the light source device in accordance with image information, and a projection optical device that projects the light modulated by the light modulation device. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram showing the configuration of a projector according to a first embodiment. [Figure 2] 1 is a schematic diagram illustrating a configuration of a light source device according to a first embodiment. [Figure 3] FIG. 10 is a schematic diagram showing the configuration of a light source device according to a first modified example. [Figure 4] FIG. 10 is a schematic diagram showing the configuration of a light source device according to a second modified example. [Figure 5] FIG. 10 is a schematic diagram showing the configuration of a light source device according to a second embodiment. [Figure 6] FIG. 10 is a schematic diagram showing the configuration of a light source device according to a third modified example. DETAILED DESCRIPTION OF THE INVENTION

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In each drawing, the scale of the dimensions of some components may be changed to make each component easier to see.

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

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

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

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

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

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

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

[0017] Each of the light modulation devices 4R, 4G, and 4B uses, for example, a transmissive liquid crystal panel. Polarizing plates (not shown) are arranged on the incident and exit sides of the liquid crystal panel. A field lens 7R is arranged on the optical path of red light RL between the first total reflection mirror 13 and the light modulation device 4R. A field lens 7G is arranged on the optical path of green light LG between the second dichroic mirror 12 and the light modulation device 4G. A field lens 7B is arranged on the optical path of blue light LB between the third total reflection mirror 15 and the light modulation device 4B.

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

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

[0020] The projection optical device 6 is configured, for example, by a plurality of optical lenses, but may also be configured by a single optical lens. Optical lenses include various lenses such as plano-convex lenses, biconvex lenses, meniscus lenses, aspherical lenses, rod lenses, and free-form lenses.

[0021] Next, a light source device according to one embodiment of the present invention will be described. Fig. 2 is a schematic diagram showing the configuration of a light source device 2 according to this embodiment. 2 and the following drawings, the components of the light source device 2 will be described using an XYZ coordinate system as necessary. The X axis is parallel to the illumination optical axis AX and optical axis ax3 of the light source device 2, the Y axis is parallel to the optical axes ax1 and ax2 of the light source device 2, and the Z axis is perpendicular to the X axis and Y axis. In other words, the optical axes ax1, ax2, and ax3 and the illumination optical axis AX are in the same plane, and the optical axes ax1 and ax2 are perpendicular to the illumination optical axis AX and optical axis ax3.

[0022] As shown in FIG. 2, the light source device 2 includes a light source 20, a diffusion element 30, an optical element 40, a wavelength conversion element 50, an optical path adjustment optical system 60, a focusing optical system 8, a reflection optical system 9, and a uniform illumination optical system 70.

[0023] In the light source device 2 of this embodiment, the light source 20, the diffusing element 30, the optical element 40, the condensing optical system 8, and the wavelength conversion element 50 are arranged on an optical axis ax1, which is the optical path of the chief ray of blue light K1 emitted from the light source 20. Also, the wavelength conversion element 50, the condensing optical system 8, the optical element 40, and the reflective optical system 9 are arranged along an optical axis ax2, which is the optical path of the chief ray of blue reflected light RB (described later) emitted from the wavelength conversion element 50. Also, the reflective optical system 9, the diffusing element 30, and the optical path adjustment optical system 60 are arranged along an optical axis ax3, which is the optical path of the chief ray of the blue reflected light RB reflected by the reflective optical system 9. Also, the optical element 40 and the optical path adjustment optical system 60 are arranged along the illumination optical axis AX.

[0024] The light source 20 includes a plurality of light-emitting units 21 and a plurality of collimating lenses 22. Each of the light-emitting units 21 is composed of a semiconductor laser. The light-emitting units 21 are arranged in an array in the XZ plane perpendicular to the optical axis ax1. Each light-emitting unit 21 emits blue light ray B, which is a light beam having a peak wavelength of, for example, 445 nm. Note that a semiconductor laser that emits light ray B with a wavelength other than 445 nm (for example, 460 nm) can also be used as the light-emitting unit 21.

[0025] The plurality of collimating lenses 22 are arranged, for example, in an array. The plurality of collimating lenses 22 are arranged corresponding to the plurality of light-emitting units 21, respectively. The collimating lenses 22 convert the light beam B emitted from the corresponding light-emitting unit 21 into parallel light.

[0026] In this way, the light source 20 emits blue light K1 as a parallel light beam having a blue wavelength band (first wavelength band) including a plurality of light rays B.

[0027] The blue light K1 emitted from the light source 20 is incident on the diffusion element 30. The diffusion element 30 transmits the blue light K1 emitted from the light source 20. The diffusion element 30 is disposed at an angle of 45° with respect to the optical axis ax1 of the blue light K1.

[0028] The diffusing element 30 is a transmissive diffuser that transmits and diffuses blue light K1. The diffusing element 30 has an incident surface 31 facing the light source 20 and an exit surface 32 facing the opposite side of the incident surface 31 and from which diffused light is emitted. The diffusing element 30 of this embodiment has an anti-reflection film 33 covering the incident surface 31 and the exit surface 32. The anti-reflection film 33 is formed, for example, of an AR coating film, and suppresses light reflection at the interface between the incident surface 31 or the exit surface 32 and an air layer. Therefore, the diffusing element 30 can efficiently allow blue light K1 to enter the incident surface 31 and efficiently emit light from the exit surface 32. Note that the anti-reflection film 33 does not need to be disposed on both surfaces of the diffusing element 30; it is sufficient to dispose the anti-reflection film 33 at least on the incident surface 31, which is the light incident side of the diffusing element 30.

[0029] The blue light K1 emitted from the diffusion element 30 is incident on the optical element 40. The optical element 40 has a first reflective film 41. The first reflective film 41 is made of a dichroic mirror that transmits the blue light K1 in the first wavelength band and reflects the fluorescence Y described below.

[0030] The blue light K1 that has passed through the optical element 40 is incident on the focusing optical system 8 that is disposed between the optical element 40 and the wavelength conversion element 50. The focusing optical system 8 includes at least one lens 18 that has positive power. The lens 18 that has positive power is configured, for example, by a convex lens or a plano-convex lens. The light-collecting optical system 8 has a function of collecting the blue light K1 toward the wavelength conversion element 50, and a function of picking up the light emitted from the wavelength conversion element 50 and collimating it.

[0031] The optical axis ax1 of the blue light K1 that passes through the optical element 40 and enters the optical element 40 is shifted with respect to the central axis 8C of the focusing optical system 8. In this embodiment, the optical axis ax1 of the blue light K1 is shifted to the +X side in the XY plane with respect to the central axis 8C of the focusing optical system 8.

[0032] For this reason, the blue light K1 is incident on the wavelength conversion element 50 from an oblique direction relative to the center of the wavelength conversion element 50 in the XY plane. In this embodiment, it is preferable that the blue light K1 does not overlap with the central axis 8C of the focusing optical system 8, and is incident only on an area on the +X side of the central axis 8C of the focusing optical system 8. In this way, the reflected component of the blue light K1 by the wavelength conversion element 50 can be efficiently extracted from the -X side of the central axis 8C, and the reflected component of the blue light K1 can be efficiently incident on the subsequent focusing optical system 8.

[0033] The wavelength conversion element 50 converts a part of the blue light K1 into fluorescent light Y. The wavelength conversion element 50 includes a wavelength conversion layer 51, a second reflective film 52, a substrate 53, and a reflective member . The wavelength conversion layer 51 contains a ceramic phosphor that converts blue light K1 in a first wavelength band into fluorescence Y in a second wavelength band different from the first wavelength band. The second wavelength band is, for example, 490 to 750 nm, and the fluorescence Y is yellow light containing a green light component and a red light component. The phosphor may contain a single crystal phosphor. The blue light K1 in this embodiment corresponds to an example of the "first light" in the present invention, and the fluorescence Y in this embodiment corresponds to an example of the "second light" in the present invention.

[0034] The substrate 53 functions as a support substrate that supports the reflecting member 54 and the wavelength conversion layer 51, and also functions as a heat dissipation substrate that dissipates heat generated in the wavelength conversion layer 51. The substrate 53 is made of a material with high thermal conductivity, such as metal or ceramic. The substrate 53 may be provided with a heat dissipation member, such as a heat sink, on the surface opposite to the surface that supports the wavelength conversion layer 51.

[0035] The reflecting member 54 is provided between the substrate 53 and the wavelength conversion layer 51, and reflects the fluorescence Y incident from the wavelength conversion layer 51 toward the wavelength conversion layer 51. The reflecting member 54 is made of a laminated film including, for example, a dielectric multilayer film, a metal mirror, and a reflection-enhancing film.

[0036] The wavelength conversion layer 51 has a first surface 51a and a second surface 51b facing in opposite directions. The first surface 51a of the wavelength conversion layer 51 is an incident surface onto which the blue light K1 is incident and also functions as an exit surface from which the fluorescence Y is emitted. The second surface 51b of the wavelength conversion layer 51 faces the substrate 53.

[0037] The wavelength conversion layer 51 contains, for example, an yttrium-aluminum-garnet (YAG) phosphor. Taking YAG:Ce, which contains cerium (Ce) as an activator, as an example, the phosphor can be a material obtained by mixing raw material powders containing constituent elements such as Y2O3, Al2O3, and CeO3 and subjecting them to a solid-phase reaction; 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.

[0038] The second reflective film 52 is provided on the first surface 51a of the wavelength conversion layer 51. The first surface 51a of the wavelength conversion layer 51 is substantially flat, and the second reflective film 52 is also made of a flat film. The second reflective film 52 is made of a dielectric multilayer film having optical properties of transmitting a portion of the blue light K1 and the fluorescent light Y and reflecting another portion of the blue light K1. In this embodiment, if the transmittance of the blue light K1 through the second reflective film 52 is set to, for example, 20%, the second reflective film 52 transmits a portion (20%) of the blue light K1 and reflects another portion (80%) of the blue light K1, thereby separating the blue light K1 into one portion and another portion.

[0039] A portion of the blue light K1 that has passed through the second reflective film 52 enters the wavelength conversion layer 51 as excitation light and is converted into fluorescence Y. The fluorescence Y passes through the second reflective film 52 provided on the first surface 51a of the wavelength conversion layer 51 and is emitted from the wavelength conversion element 50. The fluorescence Y is emitted in all directions at a wide radiation angle by Lambertian emission approximately centered in the Y-axis direction. The focusing optical system 8 of this embodiment is disposed so that the emission center of the fluorescence Y coincides with the central axis 8C. Therefore, the focusing optical system 8 can efficiently capture the fluorescence Y that has been emitted at a wide radiation angle by Lambertian emission.

[0040] The fluorescence Y is substantially collimated by the focusing optical system 8, and the chief ray of the fluorescence Y travels along the central axis 8C and is incident on the optical element 40. The fluorescence Y that has entered the optical element 40 is reflected by the first reflecting film 41, travels along the illumination optical axis AX, and is incident on the optical path adjusting optical system 60.

[0041] Meanwhile, another portion of the blue light K1 reflected by the second reflective film 52 is emitted from the wavelength conversion element 50 together with the fluorescent light Y toward the condensing optical system 8. The other portion of the blue light K1 is blue component light that, together with the yellow fluorescent light Y, generates white illumination light WL.

[0042] In the following description, the other part of the blue light K1 reflected by the second reflective film 52 may be referred to as the blue reflected light RB. In other words, the blue reflected light RB corresponds to an example of the "other part of the first light" of the present invention. As described above, according to the light source device 2 of the present embodiment, the optical path of the fluorescence Y emitted from the wavelength conversion element 50 and incident on the optical element 40 is made to coincide with the optical path of the blue reflected light RB reflected by the second reflective film 52 and incident on the optical element 40, so that the light collecting optical system 8 can also be used as an optical system that picks up the fluorescence Y and the blue reflected light RB. With this configuration, compared to a configuration in which separate optical paths are provided for the fluorescence and the blue component of the illumination light, and multiple light collecting optical systems are required, the light collecting optical system 8 can be used in combination by sharing part of the optical path, thereby making it possible to reduce the size of the device configuration.

[0043] As described above, the blue light K1 is incident on the wavelength conversion element 50 from an oblique direction and is specularly reflected by the second reflecting film 52. Therefore, the blue reflected light RB, which is a reflected component of the blue light K1, is incident on the focusing optical system 8 along an optical path different from the optical path of the blue light K1 relative to the wavelength conversion element 50. The blue reflected light RB is collimated by the focusing optical system 8, travels along the optical axis ax2, and is incident on the optical element 40. The blue reflected light RB having the first wavelength band is transmitted through the first reflecting film 41 of the optical element 40.

[0044] The blue reflected light RB is incident on the reflecting optical system 9. The reflecting optical system 9 is disposed so as to form an angle of 45° with respect to the optical axis ax2 of the blue reflected light RB. The reflecting optical system 9 reflects the blue reflected light RB emitted from the wavelength conversion element 50 along an optical axis ax3 that is perpendicular to the optical axis ax2. In this way, the chief ray of the blue reflected light RB after reflection by the reflecting optical system 9 travels along the optical axis ax3. The blue reflected light RB reflected by the reflecting optical system 9 is incident on the incident surface 31 of the diffusing element 30. In other words, the blue reflected light RB, which is another part of the blue light K1 separated by the second reflective film 52, is incident on the diffusing element 30 again.

[0045] In this way, the diffusing element 30 transmits the blue light K1 emitted from the light source 20 and transmits the reflected blue light RB emitted from the reflection optical system 9. In other words, the reflected blue light RB passes through the diffusing element 30 twice and is diffused. In this embodiment, the blue light K1 is a laser beam, which is highly coherent and easily produces visible interference fringes and speckle noise. In contrast, in this embodiment, the light is sufficiently diffused by passing through the diffusion element 30 twice, making it possible to make interference fringes less noticeable even when using blue light K1 made of laser light.

[0046] In the light source device 2 of this embodiment, the blue reflected light RB that has passed through the diffusing element 30 and the fluorescence Y that has been reflected by the optical element 40 are emitted in the same direction (the X-axis direction). In other words, the direction in which the blue reflected light RB is reflected by the reflection optical system 9 and passes through the diffusing element 30 is the same as the direction in which the fluorescence Y is reflected by the optical element 40. With this configuration, the blue reflected light RB and the fluorescence Y are emitted in the same direction, so that white illumination light WL that includes the blue reflected light RB and the fluorescence Y can be efficiently generated.

[0047] Furthermore, the light source device 2 of this embodiment further includes an optical path adjusting optical system 60 onto which the reflected blue light RB transmitted through the diffusion element 30 and the fluorescence Y reflected by the optical element 40 are incident.

[0048] The optical path adjustment optical system 60 includes a first mirror 61 and a second mirror 62 . The first mirror 61 is disposed at an angle of 45° with respect to the optical axis ax3 of the reflected blue light RB that has passed through the diffusing element 30. The second mirror 62 is disposed opposite the first mirror 61, on the -Y side of the first mirror 61 and on the +X side of the optical element 40. The second mirror 62 is disposed alongside the optical element 40 on the illumination optical axis AX.

[0049] The first mirror 61 is configured as a mirror that reflects the blue reflected light RB. The first mirror 61 reflects the blue reflected light RB toward the -Y side. The blue reflected light RB reflected by the first mirror 61 is incident on the second mirror 62. The second mirror 62 is configured as a dichroic mirror that has the optical property of reflecting the blue reflected light RB, which is light in a first wavelength band, and transmitting the fluorescence Y, which is light in a second wavelength band.

[0050] By being reflected by the first mirror 61 and the second mirror 62, the optical path of the reflected blue light RB is shifted to the -Y side and approaches the illumination optical axis AX before and after passing through the optical path adjustment optical system 60. Because the fluorescence Y passes through the second mirror 62, the optical path of the fluorescence Y does not change before and after passing through the optical path adjustment optical system 60.

[0051] The optical path adjustment optical system 60 brings the optical path of the blue reflected light RB reflected by the reflection optical system 9 closer to the optical path (illumination optical axis AX) of the fluorescence Y reflected by the optical element 40. Therefore, the optical path adjustment optical system 60 can make the optical paths of the blue reflected light RB and the fluorescence Y at least partially overlap each other. With this configuration, overlapping the optical paths of the blue reflected light RB and the fluorescence Y can suppress color unevenness of the illumination light WL.

[0052] As described above, in the light source device 2 of this embodiment, the optical path adjustment optical system 60 generates white illumination light WL by guiding the blue reflected light RB to the optical path of the fluorescence Y, and causes the white illumination light WL to enter the uniform illumination optical system 70. The uniform illumination optical system 70 is disposed along the illumination optical axis AX of the light source device 2. The uniform illumination optical system 70 has a first lens array 71, a second lens array 72, a polarization conversion element 73, and a superimposing lens 74.

[0053] The first lens array 71 has a plurality of first lenses 71a for dividing the illumination light WL incident from the optical path adjustment optical system 60 into a plurality of partial light beams. The plurality of first lenses 71a are arranged in a matrix in a plane perpendicular to the illumination optical axis AX.

[0054] The second lens array 72 has a plurality of second lenses 72a corresponding to the plurality of first lenses 71a of the first lens array 71. The plurality of second lenses 72a are arranged in a matrix in a plane perpendicular to the illumination optical axis AX. The second lens array 72, together with the superimposing lens 74, forms images of the first lenses 71a of the first lens array 71 near the image forming areas of the light modulation device 4R, the light modulation device 4G, and the light modulation device 4B, respectively.

[0055] The polarization conversion element 73 converts the light emitted from the second lens array 72 into one type of linearly polarized light. The polarization conversion element 73 includes, for example, a polarization separation film and a phase difference plate (not shown).

[0056] The superimposing lens 74 collects the partial light beams emitted from the polarization conversion element 73 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 70 may also include a rod lens that uniforms the illuminance distribution of light.

[0057] As described above, the light source device 2 of this embodiment includes the light source 20 that emits blue light K1 in a blue wavelength band, the diffusion element 30 onto which the blue light K1 emitted from the light source 20 is incident, the optical element 40 onto which the blue light K1 that has passed through the diffusion element 30 is incident, the focusing optical system 8 onto which the blue light K1 that has passed through the optical element 40 is incident, the wavelength conversion element 50 that converts a portion of the blue light K1 into fluorescence Y in a yellow wavelength band different from the blue wavelength band, and the reflection optical system 9 that reflects blue reflected light RB, which is another portion of the blue light K1 emitted from the wavelength conversion element 50. The optical element 40 has a first reflection film 41 that transmits the blue light K1 and reflects the fluorescence Y. The wavelength conversion element 50 has a wavelength conversion layer 51 having a first surface 51a onto which the blue light K1 is incident, and a second reflection film 52 provided on the first surface 51a that separates the blue light K1 into excitation light and blue reflected light RB. The blue reflected light RB separated by the second reflective film 52 is incident on the diffusing element 30.

[0058] According to the light source device 2 of this embodiment, the blue light K1 emitted from the light source 20 can be separated into excitation light and blue components of illumination light by the second reflective film 52 provided on the first surface 51a of the wavelength conversion element 50. This allows the optical path of the fluorescence Y emitted from the wavelength conversion element 50 to partially coincide with the optical path of the blue component reflected by the second reflective film 52, thereby making it possible to miniaturize the device configuration.

[0059] Furthermore, in the light source device 2 of this embodiment, the reflected blue light RB is sufficiently diffused by passing through the diffusing element 30 twice. Therefore, even when highly coherent laser light is used as the blue light K1, the light source device 2 of this embodiment can make interference fringes and speckle noise generated in the illumination light WL less noticeable. Therefore, the light source device 2 of this embodiment can generate illumination light WL in which interference fringes and speckle noise are suppressed.

[0060] The uniform illumination optical system 70 in the light source device 2 of this embodiment is not an essential component, and it is possible to omit the uniform illumination optical system 70 depending on the illuminance distribution required for the illumination light WL.

[0061] The projector 1 of this embodiment includes the light source device 2, and therefore can be a compact projector that displays high-quality color images with reduced interference fringes and speckle noise.

[0062] (First Modification) Next, a light source device of a first modified example will be described with reference to the drawings. The basic configuration of this modified example is the same as that of the first embodiment, but the layout of the light source relative to the diffusion element is different from that of the first embodiment. Therefore, the following mainly describes the configuration due to the difference in layout, and components common to the drawings used in the above embodiment are assigned the same reference numerals and will not be described again.

[0063] FIG. 3 is a schematic diagram showing the configuration of a light source device 2A of this modified example. As shown in FIG. 3, a light source device 2A of this modification includes a light source 20, a diffusion element 30, an optical element 40, a wavelength conversion element 50, a light collecting optical system 8, and a reflection optical system 9.

[0064] In the light source device 2A of this modified example, the light source 20, the diffusing element 30, and the reflective optical system 9 are arranged along an optical axis ax4, which is the optical path of the chief ray of the blue light K1 emitted from the light source 20. In addition, the reflective optical system 9, the optical element 40, the condensing optical system 8, and the wavelength conversion element 50 are arranged along an optical axis ax5, which is the optical path of the chief ray of the blue light K1 reflected by the reflective optical system 9. In addition, the wavelength conversion element 50, the condensing optical system 8, the optical element 40, and the diffusing element 30 are arranged along an optical axis ax6, which is the optical path of the chief ray of the blue reflected light RB emitted from the wavelength conversion element 50.

[0065] In this modification, light source 20 emits blue light K1 from the +X side of diffusion element 30. Blue light K1 passes through diffusion element 30 and enters reflection optical system 9. Reflection optical system 9 reflects blue light K1 that has passed through diffusion element 30 along optical axis ax5.

[0066] The blue light K1 reflected by the reflection optical system 9 is incident on the optical element 40. The optical element 40 transmits the blue light K1 in the first wavelength band. The blue light K1 that has passed through the optical element 40 is incident on the focusing optical system 8.

[0067] The optical axis ax1 of the blue light K1 is deviated from the central axis 8C of the focusing optical system 8. In this modification, the optical axis ax1 of the blue light K1 is deviated to the -X side in the XY plane from the central axis 8C of the focusing optical system 8. Therefore, the blue light K1 is incident on the center of the wavelength conversion element 50 at an angle.

[0068] Another part of the blue light K1 is reflected by the second reflecting film 52 as blue reflected light RB, and passes through an optical path different from the optical path of the blue light K1 to be incident on the focusing optical system 8. The blue reflected light RB is collimated by the focusing optical system 8, travels along the optical axis ax6, and transmits through the optical element 40 and the diffusing element 30. The fluorescence Y generated by the wavelength conversion element 50 is substantially collimated by the light collection optical system 8, enters the optical element 40, and is reflected by the optical element 40 toward the +X side.

[0069] In the light source device 2A of this modification, the reflected blue light RB, which is another part of the blue light K1 separated by the second reflective film 52, is incident on the diffusing element 30 again, and is diffused by passing through the diffusing element 30 twice. Therefore, even when the blue light K1 consisting of laser light is used, the occurrence of interference fringes and speckle noise can be made less noticeable.

[0070] As described above, the light source device 2A of this modified example includes a light source 20 that emits blue light K1 in a blue wavelength band, a diffusing element 30 that transmits the blue light K1 emitted from the light source 20, a reflective optical system 9 that reflects the blue light K1 that has passed through the diffusing element 30, an optical element 40 onto which the blue light K1 reflected by the reflective optical system 9 is incident, a focusing optical system 8 onto which the blue light K1 that has passed through the optical element 40 is incident, and a wavelength conversion element 50 that converts a portion of the blue light K1 into fluorescence Y in a yellow wavelength band different from the blue wavelength band. The optical element 40 has a first reflective film 41 that transmits the blue light K1 and reflects the fluorescence Y. The wavelength conversion element 50 has a wavelength conversion layer 51 having a first surface 51a onto which the blue light K1 is incident, and a second reflective film 52 provided on the first surface 51a that separates the blue light K1 into excitation light and blue reflected light RB. The blue reflected light RB separated by the second reflective film 52 is incident on the diffusing element 30.

[0071] According to the light source device 2A of this modification, the blue light K1 emitted from the light source 20 can be separated into excitation light and blue components of illumination light by the second reflective film 52 provided on the first surface 51a of the wavelength conversion element 50. This allows the optical path of the fluorescence Y emitted from the wavelength conversion element 50 to partially coincide with the optical path of the blue component reflected by the second reflective film 52, thereby making it possible to miniaturize the device configuration.

[0072] In the light source device 2A of this modification, the emission direction of the fluorescence Y (X-axis direction) and the emission direction of the reflected blue light RB (Y-axis direction) are different, but the emission directions of the fluorescence Y and the reflected blue light RB may be aligned by arranging a reflective member such as a mirror in the optical path of either the fluorescence Y or the reflected blue light RB. Also, a uniform illumination optical system 70 may be arranged, similar to the light source device 2 of the first embodiment.

[0073] (Second Modification) Next, a light source device of a second modified example will be described with reference to the drawings. The basic configuration of this modified example is the same as that of the first embodiment, but the configuration of the diffusion element is different from that of the first embodiment. Therefore, the following mainly describes the configuration due to the difference in the diffusion element, and components common to the drawings used in the above embodiment are assigned the same reference numerals and will not be described again.

[0074] FIG. 4 is a schematic diagram showing the configuration of a light source device 2B of this modified example. As shown in FIG. 4, the light source device 2B of this modified example includes a light source 20, a diffusion element 130, an optical element 40, a wavelength conversion element 50, a light collecting optical system 8, and a reflection optical system 9.

[0075] In the light source device 2B of this modified example, the light source 20, the diffusing element 30, and the reflective optical system 9 are arranged on an optical axis ax4, which is the optical path of the chief ray of the blue light K1 emitted from the light source 20. The diffusing element 130, the optical element 40, the condensing optical system 8, and the wavelength conversion element 50 are arranged along an optical axis ax7, which is the optical path of the chief ray of the blue light K1 reflected by the diffusing element 130. The wavelength conversion element 50, the condensing optical system 8, the optical element 40, and the reflective optical system 9 are arranged along an optical axis ax2, which is the optical path of the chief ray of the blue reflected light RB emitted from the wavelength conversion element 50. The reflective optical system 9, the diffusing element 130, and the light source 20 are arranged along an optical axis ax3, which is the optical path of the chief ray of the blue reflected light RB reflected by the reflective optical system 9.

[0076] In this modification, the diffusing element 130 is a reflective diffuser that diffuses blue light K1 by reflecting it. The diffusing element 130 includes a base material 131 and a reflective layer 133. The base material 131 is made of a translucent substrate such as glass or plastic, and has a flat surface 131a and a diffusing surface 131b that faces the opposite side to the flat surface 131a and includes an uneven structure 132 made up of a plurality of uneven surfaces. The reflective layer 133 is made of, for example, a metal film or a dielectric multilayer film, and covers the surface of the uneven structure 132 of the base material 131. The diffusing surface 131b in this modification corresponds to "one surface of the base material" in the present invention.

[0077] Blue light K1 emitted from light source 20 is incident on diffusion surface 131b from flat surface 131a of base material 131 of diffusion element 130. Blue light K1 incident on diffusion surface 131b is diffused by diffusion surface 131b and reflected by reflective layer 133, and is emitted from diffusion element 130 to the -Y side. The chief ray of blue light K1 diffused and reflected from diffusion element 130 travels along optical axis ax6 and is incident on optical element 40.

[0078] The blue light K1 passes through the optical element 40 and enters the focusing optical system 8. The optical axis ax6 of the blue light K1 is deviated from the central axis 8C of the focusing optical system 8. In this modification, the optical axis ax1 of the blue light K1 is deviated from the central axis 8C of the focusing optical system 8 to the +X side in the XY plane, so that the blue light K1 is obliquely incident on the center of the wavelength conversion element 50.

[0079] Another part of the blue light K1 is reflected by the second reflecting film 52 as blue reflected light RB, collimated by the focusing optical system 8, travels along the optical axis ax2, passes through the optical element 40, and is incident on the reflecting optical system 9. The blue reflected light RB is reflected by the reflecting optical system 9 along the optical axis ax3, and is incident on the diffusing element 130 from the -X side.

[0080] The reflected blue light RB is incident on the diffusing surface 131b side of the diffusing element 130. The reflected blue light RB incident on the diffusing element 130 is diffused by the diffusing surface 131b and reflected by the reflective layer 133 that covers the diffusing surface 131b. As a result, the reflected blue light RB is emitted from the diffusing element 130 to the +Y side. The fluorescence Y generated by the wavelength conversion element 50 is substantially collimated by the light collection optical system 8, enters the optical element 40, and is reflected by the optical element 40 toward the +X side.

[0081] In the light source device 2B of this modification, the blue reflected light RB, which is another part of the blue light K1 separated by the second reflective film 52, is incident on the diffusing element 130 again, and is diffused by passing through the diffusing element 130 twice. Therefore, even when blue light K1 consisting of laser light is used, the occurrence of interference fringes and speckle noise can be made less noticeable.

[0082] As described above, according to the light source device 2B of this modified example, even when the light-reflecting diffusion element 130 is used, the blue light K1 emitted from the light source 20 can be separated into excitation light and blue components of illumination light by the second reflective film 52 provided on the first surface 51a of the wavelength conversion element 50. This allows the optical path of the fluorescence Y emitted from the wavelength conversion element 50 to partially coincide with the optical path of the blue component reflected by the second reflective film 52, thereby making it possible to miniaturize the device configuration.

[0083] In the light source device 2B of this modified example, the emission direction of the fluorescence Y (X-axis direction) and the emission direction of the reflected blue light RB (Y-axis direction) are different, but the emission directions of the fluorescence Y and the reflected blue light RB may be aligned by arranging a reflective member such as a mirror in the optical path of either the fluorescence Y or the reflected blue light RB. Also, a uniform illumination optical system 70 may be arranged, similar to the light source device 2 of the first embodiment.

[0084] In addition, in this modified example, the diffusion element 130 has one side of the base material 131 as the diffusion surface 131b, but a diffusion element having a configuration in which both sides are diffusion surfaces by providing an uneven structure on both sides of the base material may also be used.

[0085] (Second embodiment) Next, a light source device according to a second embodiment of the present invention will be described. The basic configuration of the second embodiment is the same as that of the first embodiment, but the configurations of the optical elements and the reflective optical system are different from those of the first embodiment. Therefore, the configurations of the optical elements and the reflective optical system will be mainly described below, and components common to those in the drawings used in the above embodiments will be assigned the same reference numerals and will not be described again.

[0086] FIG. 5 is a schematic diagram showing the configuration of a light source device 102 according to the second embodiment. As shown in FIG. 5, the light source device 102 of this embodiment includes a light source 20, a diffusion element 30, an optical element 40, a wavelength conversion element 50, a focusing optical system 8, a reflection optical system 90, and a uniform illumination optical system 70.

[0087] In the light source device 102 of this embodiment, the optical element 40 is provided on the diffusion element 30. Specifically, the optical element 40 is provided on the exit surface 32 of the diffusion element 30. The diffusion element 30 of this embodiment has an anti-reflection film 33 covering the entrance surface 31.

[0088] The reflective optical system 90 includes a first reflective element 91 and a second reflective element 92 disposed between the first reflective element 91 and the optical element 40. The first reflective element 91 and the second reflective element 92 are disposed to face each other with a gap therebetween, and are disposed so as to form an angle of 45° with respect to the optical axis ax2 of the reflected blue light RB.

[0089] The first reflecting element 91 is a mirror made of, for example, a metal film or a dielectric multilayer film, and reflects incident light. The second reflecting element 92 is a mirror with semi-transmissive reflectivity that reflects part of the incident light and transmits the rest. The second reflecting element 92 of this embodiment is configured as a so-called half mirror that transmits half of the incident light and reflects the rest.

[0090] In the light source device 102 of this embodiment, the fluorescence Y emitted from the wavelength conversion element 50 is reflected by the optical element 40 and travels along the illumination optical axis AX. The blue reflected light RB emitted from the wavelength conversion element 50 passes through the optical element 40 and the diffusion element 30 and is incident on the second reflecting element 92. A first blue reflected light RB1, which is a part of the blue reflected light RB, is reflected by the second reflecting element 92 toward the +X side and re-enters the diffusing element 30. A second blue reflected light RB2, which is the remaining part of the blue reflected light RB, passes through the second reflecting element 92, is reflected by the first reflecting element 91 toward the +X side, and re-enters the diffusing element 30.

[0091] The blue reflected light RB passes through the diffusing element 30 once and then enters the reflective optical system 90, where it is separated into a first blue reflected light RB1 and a second blue reflected light RB2, which then pass through the diffusing element 30 again. In this way, in the light source device 102 of this embodiment, the blue reflected light RB enters the diffusing element 30 both before and after entering the reflective optical system 90.

[0092] In the light source device 102 of this embodiment, the blue reflected light RB, which is the reflected component of the blue light K1 that has passed through the diffusion element 30, becomes more diffused by passing through the diffusion element 30 three times, thereby making interference fringes and speckle noise that occur in the illumination light WL less noticeable.

[0093] The second blue reflected light RB2 reflected by the first reflecting element 91 passes through the diffusing element 30 and the optical element 40 and travels along the illumination optical axis AX. The optical path of the second blue reflected light RB2 overlaps at least a part of the optical path of the fluorescence Y reflected by the optical element 40. Furthermore, the first blue reflected light RB1 reflected by the second reflecting element 92 passes through the diffusing element 30 and the optical element 40 and travels along the illumination optical axis AX. The optical path of the first blue reflected light RB1 overlaps at least a part of the optical path of the fluorescence Y reflected by the optical element 40.

[0094] As described above, according to light source device 102 of the present embodiment, the reflection optical system 90 can be used to separate blue reflected light RB in a direction perpendicular to the illumination optical axis AX, i.e., in the direction of the beam width of fluorescence Y, so that the optical paths of first blue reflected light RB1 and second blue reflected light RB2 can be superimposed on the optical path of fluorescence Y. This makes the apparent beam width of blue reflected light RB approach the beam width of fluorescence Y, and reduces the difference in the beam widths of blue reflected light RB and fluorescence Y contained in illumination light WL, thereby suppressing color unevenness in illumination light WL.

[0095] (Third Modification) Next, a light source device of a third modified example will be described with reference to the drawings. The basic configuration of this modified example is the same as that of the second embodiment, but the layout of the reflective optical system is different from that of the second embodiment. Therefore, the configuration of the reflective optical system will be mainly described below, and components common to those in the drawings used in the above embodiment will be assigned the same reference numerals and will not be described again.

[0096] FIG. 6 is a schematic diagram showing the configuration of a light source device 102A of this modified example. 6, in the light source device 102A of this modified example, the second reflecting element 92 of the reflective optical system 90 is provided on the diffusing element 30. Specifically, the second reflecting element 92 is provided on a part of the incident surface 31 of the diffusing element 30. The second reflecting element 92 is provided at least in an area where the blue reflected light RB emitted from the wavelength conversion element 50 is incident. The incident surface 31 has an anti-reflection coating 33 in an area other than the area where the second reflecting element 92 is arranged. In other words, the diffusing element 30 of this modified example has the anti-reflection coating 33 and the second reflecting element 92 on the incident surface 31.

[0097] According to light source device 102A of this modification, incident surface 31 of diffusion element 30 can be used as a support member for second reflecting element 92, so that a separate support member for supporting second reflecting element 92 can be omitted.

[0098] The technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. In addition, the specific descriptions of the shape, number, arrangement, material, etc. of each component of the light source device and projector are not limited to the above-described embodiments and can be changed as appropriate.

[0099] A summary of this disclosure is provided below.

[0100] (Appendix 1) a light source that emits a first light in a first wavelength band; a diffusion element onto which the first light emitted from the light source is incident; an optical element onto which the first light that has passed through the diffusion element is incident; a focusing optical system into which the first light that has passed through the optical element is incident; a wavelength conversion element that converts a portion of the first light into second light in a second wavelength band different from the first wavelength band; a reflection optical system that reflects another part of the first light emitted from the wavelength conversion element, the optical element has a first reflective film that transmits the first light and reflects the second light, the wavelength conversion element includes a wavelength conversion layer having a first surface onto which the first light is incident, and a second reflective film provided on the first surface to separate the first light into the part and the other part, the other part of the first light separated by the second reflective film is incident on the diffusion element. Light source device.

[0101] According to the light source device having this configuration, the second reflective film provided on the first surface of the wavelength conversion element can separate the first light emitted from the light source into a part of light for wavelength conversion and another part of light for illumination, thereby making it possible to downsize the device configuration by partially matching the optical path of the second light emitted from the wavelength conversion element and the optical path of the illumination light reflected by the second reflective film. Furthermore, because the remaining part of the light used for illumination is sufficiently diffused by passing through the diffusion element twice, interference fringes and speckle noise generated in the illumination light can be made less noticeable, even when, for example, highly coherent laser light is used as the first light, thereby making it possible to provide a light source device that generates illumination light with reduced interference fringes and speckle noise.

[0102] (Appendix 2) the focusing optical system includes a lens having a positive power; an optical axis of the first light that passes through the optical element and enters the optical element is shifted from a central axis of the light-collecting optical system; 10. The light source device of claim 1.

[0103] With this configuration, the first light is incident obliquely onto the center of the wavelength conversion element, and another part of the first light is reflected by the second reflective film and passes through an optical path different from the optical path of the first light, and is made to enter the focusing optical system.

[0104] (Appendix 3) the diffusion element transmits the first light emitted from the light source and transmits the other part of the first light emitted from the reflection optical system; 10. The light source device according to claim 1 or 2.

[0105] According to this configuration, when a transmissive diffusion element is used, it is possible to provide a light source device that can be made compact in configuration.

[0106] (Appendix 4) The diffusion element is a light-transmitting diffusion element, and has an anti-reflection film provided at least on the light incident side onto which the first light is incident. 10. The light source device according to claim 1 or 2.

[0107] This configuration suppresses reflection of light at the interface between the incident surface and the air layer, allowing the diffusing element to efficiently direct the first light to the incident surface.

[0108] (Appendix 5) a direction in which the other part of the first light is reflected by the reflection optical system and transmitted through the diffusion element is along a direction in which the second light is reflected by the optical element; 10. The light source device of claim 1.

[0109] According to this configuration, the other part of the first light and the second light are emitted in the same direction, so that illumination light including the first light and the second light can be generated efficiently.

[0110] (Appendix 6) further comprising an optical path adjustment optical system that brings the optical path of another part of the first light reflected by the reflection optical system closer to the optical path of the second light reflected by the optical element; 6. The light source device according to claim 5.

[0111] According to this configuration, the optical path adjusting optical system can make the optical paths of the other part of the first light and the second light overlap with each other, thereby suppressing color unevenness in the illumination light by overlapping the optical paths of the other part of the first light and the second light.

[0112] (Appendix 7) The diffusion element includes a light-transmitting substrate having an uneven structure provided on one surface thereof, and a reflective layer covering the uneven structure of the substrate. 10. The light source device according to claim 1 or 2.

[0113] This configuration provides a light-reflecting diffusion element that diffuses light incident from one side of the base material by the uneven surface and reflects it from the reflective layer, and diffuses light incident from the other side of the base material by the reflective layer covering the uneven surface, thereby providing a light source device with a compact configuration even when using a light-reflecting diffusion element. can.

[0114] (Appendix 8) the optical element is provided on the diffusing element, the reflective optical system includes the first reflective element that reflects incident light, and a second reflective element that is disposed between the first reflective element and the optical element and that reflects a portion of the incident light and transmits the remainder of the portion; an optical path of the light reflected by the first reflecting element overlaps with at least a part of an optical path of the second light reflected by the optical element; an optical path of the light reflected by the second reflecting element overlaps with at least a portion of an optical path of the second light reflected by the optical element; 7. A light source device according to any one of claims 1 to 6.

[0115] According to this configuration, the reflection optical system can separate the other part of the first light into two in the beam width direction of the second light, and the optical paths of the separated lights can be made to overlap with the optical path of the second light. This makes the apparent beam width of the other part of the first light closer to the beam width of the second light, and reduces the difference in beam width between the other part of the first light and the second light contained in the illumination light, thereby suppressing color unevenness in the illumination light.

[0116] (Appendix 9) the other portion of the first light is incident on the diffusion element before and after being incident on the reflection optical system, 9. The light source device according to claim 8.

[0117] With this configuration, the remaining light, which is the reflected component of the first light that has passed through the diffusing element, passes through the diffusing element three times, becoming more diffused, thereby making interference fringes and speckle noise that occur in the illumination light less noticeable.

[0118] (Appendix 10) The second reflective element is provided on the diffusing element. 10. The light source device according to claim 8 or 9.

[0119] According to this configuration, the diffusion element can be used as a support member for the second reflecting element, so that a separate support member for supporting the second reflecting element can be omitted.

[0120] (Appendix 11) a light source that emits a first light having a first wavelength band; a diffusion element that transmits the first light emitted from the light source; a reflective optical system that reflects the first light that has passed through the diffusing element; an optical element onto which the first light reflected by the reflection optical system is incident; a focusing optical system into which the first light that has passed through the optical element is incident; a wavelength conversion element that converts a part of the first light into second light of a second wavelength band different from the first wavelength band, the optical element has a first reflective film that transmits the first light and reflects the second light, the wavelength conversion element includes a wavelength conversion layer having a first surface onto which the first light is incident, and a second reflective film provided on the first surface to separate the first light into the part and another part, the other part of the first light separated by the second reflective film is incident on the diffusion element. Light source device.

[0121] According to this configuration, the second reflective film provided on the first surface of the wavelength conversion element can separate the first light emitted from the light source into a part of light for wavelength conversion and another part of light for illumination, thereby making it possible to downsize the device configuration by partially matching the optical path of the second light emitted from the wavelength conversion element and the optical path of the illumination light reflected by the second reflective film. Furthermore, because the remaining part of the light used for illumination is sufficiently diffused by passing through the diffusion element twice, interference fringes and speckle noise generated in the illumination light can be made less noticeable, even when, for example, highly coherent laser light is used as the first light, thereby making it possible to provide a light source device that generates illumination light with reduced interference fringes and speckle noise.

[0122] (Appendix 12) the wavelength conversion element further includes a substrate supporting a second surface of the wavelength conversion layer opposite to the first surface, and a reflecting member provided between the substrate and the second surface of the wavelength conversion layer and reflecting the second light. 12. A light source device according to any one of claims 1 to 11.

[0123] According to this configuration, the second light can be reflected by the reflecting member toward the wavelength conversion layer, and therefore the second light can be extracted efficiently from the wavelength conversion element.

[0124] (Appendix 13) a light source device according to any one of Supplementary Note 1 to Supplementary Note 12; a light modulation device that modulates light incident from the light source device; a projection optical device that projects the light modulated by the light modulation device; Equipped with projector.

[0125] According to a projector having this configuration, since it is equipped with the light source device, it is possible to realize a small projector that displays high-quality color images with reduced interference fringes and speckle noise. [Explanation of symbols]

[0126] 1...projector, 2, 2A, 2B, 102, 102A...light source device, 4B, 4G, 4R...light modulation device, 6...projection optical device, 8...focusing optical system, 8C...central axis, 9, 90...reflection optical system, 18...lens, 20...light source, 30, 130...diffusion element, 33...anti-reflection film, 40...optical element, 41...first reflective film, 50...wavelength conversion element, 51...wavelength conversion layer, 51a...first surface, 51b...second surface, 52...second reflective film, 53...substrate, 54...reflective member, 60...optical path adjustment optical system, 91...first reflective element, 92...second reflective element, 131...base material, 132...uneven structure, 133...reflective layer, K1...blue light (first light), Y...fluorescent (second light).

Claims

1. a light source that emits first light in a first wavelength band; a diffusion element onto which the first light emitted from the light source is incident; an optical element onto which the first light that has passed through the diffusion element is incident; a focusing optical system into which the first light that has passed through the optical element is incident; a wavelength conversion element that converts a portion of the first light into second light in a second wavelength band different from the first wavelength band; a reflection optical system that reflects another part of the first light emitted from the wavelength conversion element, the optical element has a first reflecting film that transmits the first light and reflects the second light, the wavelength conversion element includes a wavelength conversion layer having a first surface onto which the first light is incident, and a second reflective film provided on the first surface to separate the first light into the part and the other part, the other part of the first light separated by the second reflective film is incident on the diffusion element; Light source device.

2. the focusing optical system includes a lens having a positive power; an optical axis of the first light that is transmitted through the optical element and incident thereon is shifted from a central axis of the light collecting optical system; The light source device according to claim 1 .

3. the diffusion element transmits the first light emitted from the light source and transmits the other part of the first light emitted from the reflection optical system; The light source device according to claim 1 .

4. the diffusion element is a light-transmitting diffusion element, and has an anti-reflection film provided at least on a light incident side onto which the first light is incident; The light source device according to claim 1 .

5. a direction in which the other part of the first light is reflected by the reflection optical system and transmitted through the diffusion element is along a direction in which the second light is reflected by the optical element; The light source device according to claim 1 .

6. further comprising an optical path adjusting optical system that brings the optical path of another part of the first light reflected by the reflecting optical system closer to the optical path of the second light reflected by the optical element; The light source device according to claim 5 .

7. The diffusion element includes a light-transmitting substrate having an uneven structure provided on one surface thereof, and a reflective layer covering the uneven structure of the substrate. The light source device according to claim 1 .

8. the optical element is provided on the diffusing element, the reflective optical system includes the first reflective element that reflects incident light, and a second reflective element that is disposed between the first reflective element and the optical element and that reflects a portion of the incident light and transmits the remainder of the portion; an optical path of the light reflected by the first reflecting element overlaps with at least a part of an optical path of the second light reflected by the optical element; an optical path of the light reflected by the second reflecting element overlaps with at least a portion of an optical path of the second light reflected by the optical element; The light source device according to claim 1 .

9. The other part of the first light is incident on the diffusion element before and after being incident on the reflection optical system. The light source device according to claim 8 .

10. The second reflective element is provided on the diffusing element.

10. The light source device according to claim 8 or 9.

11. a light source that emits first light having a first wavelength band; a diffusion element that transmits the first light emitted from the light source; a reflective optical system that reflects the first light that has passed through the diffusing element; an optical element onto which the first light reflected by the reflection optical system is incident; a focusing optical system into which the first light that has passed through the optical element is incident; a wavelength conversion element that converts a part of the first light into second light of a second wavelength band different from the first wavelength band, the optical element has a first reflecting film that transmits the first light and reflects the second light, the wavelength conversion element includes a wavelength conversion layer having a first surface onto which the first light is incident, and a second reflective film provided on the first surface to separate the first light into the part and another part, the other part of the first light separated by the second reflective film is incident on the diffusion element; Light source device.

12. The wavelength conversion element further includes a substrate supporting a second surface of the wavelength conversion layer opposite to the first surface, and a reflecting member provided between the substrate and the second surface of the wavelength conversion layer and reflecting the second light. The light source device according to claim 1 or 11.

13. The light source device according to claim 1 or 11; a light modulation device that modulates light incident from the light source device; a projection optical device that projects the light modulated by the light modulation device; Equipped with projector.

Images