Light source device and projector

Abstract

A light source device and a projector capable of switching between a color reproduction emphasis mode and a brightness emphasis mode are provided. The light source device includes a first light source section that emits first light of a first wavelength band including a first polarization component and a second polarization component; a second light source section that emits second light of a second wavelength band; a wavelength conversion element that converts the first light into third light of a third wavelength band; a light combining element that combines the first light, the second light, and the third light; and a filter that attenuates light of a part of the third wavelength band when the third light is incident. The light combining element reflects light of the first polarization component and transmits light of the second polarization component in the first light, so that either of the light of the first polarization component and the light of the second polarization component is emitted toward the wavelength conversion element. The first light and the second light are transmitted through either of the third light, and the other is reflected. The filter is movable between a first position at which the third light is transmitted through the filter and a second position at which the third light is not transmitted through the filter.

Description

Technical Field

[0001] This invention relates to light source devices and projectors. Background Technology

[0002] As a light source device for a projector, a light source device has been proposed that utilizes fluorescence emitted from a phosphor when excitation light emitted from a light-emitting element is irradiated by the phosphor. For example, Patent Document 1 discloses a light source device comprising: a first light source that emits blue light; a phosphor that is excited by blue light and emits green light; a second light source that emits red light; a first dichroic mirror that allows blue light to pass through and reflects green light; and a second dichroic mirror that allows both blue and green light to pass through and reflects red light.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2014-186115

[0004] In recent years, projectors have sometimes required users to choose between a mode that prioritizes color reproduction and a mode that prioritizes brightness. To achieve this, a light source device capable of switching between these two modes is needed.

[0005] When using a phosphor to generate a specific color of light, such as green light, as in Patent Document 1, a decrease in the purity of the green light cannot be avoided compared to using a green laser. As a result, color reproducibility is reduced in projectors equipped with such a light source device. Patent Document 1 describes the efficient use of red light by narrowing the filter of the second dichroic mirror, but in the light source device of Patent Document 1, there is a problem that it is impossible to switch between a color reproducibility-focused mode and a brightness-focused mode. Summary of the Invention

[0006] To address the aforementioned issues, one aspect of the present invention provides a light source device comprising: a first light source unit that emits first light in a first wavelength band, the first light in the first wavelength band including a first polarization component and a second polarization component different from the first polarization component; a second light source unit that emits second light in a second wavelength band different from the first wavelength band; a wavelength conversion element that converts the first light into third light in a third wavelength band different from the first and second wavelength bands; a light combining element that combines the first light, the second light, and the third light to emit combined light; and a filter to which the third light is incident. The filter reduces the light intensity of a portion of the third band. The light combining element reflects the first polarization component of the first light emitted from the first light source and allows the second polarization component to pass through. This allows the wavelength conversion element to emit light from either the first polarization component or the second polarization component in either direction. The light combining element allows either the first light, the second light, or the third light to pass through and reflects the other. The filter is movable between a first position where the third light passes through the filter and a second position where the third light does not pass through the filter.

[0007] One aspect of the present invention provides a projector comprising: a light source device according to one aspect of the present invention; a light modulation device for modulating light comprising composite light emitted from the light source device according to image information; and a projection optics device for projecting light modulated by the light modulation device. Attached Figure Description

[0008] Figure 1 This is a schematic structural diagram of the projector according to the first embodiment.

[0009] Figure 2 This is a schematic structural diagram of the light source device according to the first embodiment.

[0010] Figure 3 This is a graph showing the spectral characteristics of the first optical film of the filter.

[0011] Figure 4 This is a graph showing the spectral characteristics of the second optical film of the filter.

[0012] Figure 5 This is a graph showing the spectral characteristics of the third optical film of the photosynthesizing element.

[0013] Figure 6 This is a graph showing the spectral characteristics of the fourth optical film of the photosynthesizing element.

[0014] Figure 7 This is a graph showing the spectral characteristics of the first optical film of the modified filter.

[0015] Figure 8 It is a chart showing the emission spectrum of each light source.

[0016] Figure 9 This is a graph showing the spectrum of green light after passing through the filter.

[0017] Figure 10 This is a graph showing the relationship between the illuminance distribution of blue light and the direction of filter movement.

[0018] Figure 11 This is a graph showing the relationship between the illuminance distribution of green light and the direction of filter movement.

[0019] Figure 12 This is a schematic structural diagram of the light source device according to the second embodiment.

[0020] Figure 13 This is a schematic structural diagram of the light source device according to the third embodiment.

[0021] Figure 14 This is a graph showing the spectral characteristics of the second optical film of the filter.

[0022] Figure 15 This is a schematic structural diagram of the light source device according to the fourth embodiment.

[0023] Figure 16 This is a graph showing the spectral characteristics of the fifth optical film of the second photosynthesizing element.

[0024] Figure 17 This is a schematic structural diagram of the light source device according to the fifth embodiment.

[0025] Figure 18 This is an enlarged view of the main parts of the light source device.

[0026] Label Explanation

[0027] 10: Projector; 11: First light source unit; 12: Second light source unit; 13: Wavelength conversion element; 14, 64: Light combining element; 15, 55, 85: Filter; 15a: Light incident surface; 16: Parallelization element; 17: Diffuser; 21: Integrator optical element (first optical element); 22: Polarization conversion element (second optical element); 22A: First light incident region; 22B: Second light incident region; 24: Control unit; 27: First light emitting element; 29: The... 1. Phase difference plate (first phase difference element); 85A: first filter section; 85B: second filter section; 100, 120, 130, 140, 150: light source device; 400R, 400G, 400B: light modulation device; 600: projection optical device; LBp, LBs, LBc1, LBc2: blue light (first beam); LR, LRp, LRs: red light (second beam); LG: green light (third beam); L1: first beam; L2: second beam. Detailed Implementation

[0028] [First Implementation]

[0029] The following uses Figures 1 to 11 The first embodiment of the present invention will be described.

[0030] The projector in this embodiment is an example of a liquid crystal projector equipped with a light source device that uses a semiconductor laser and a phosphor.

[0031] Furthermore, in the following figures, the scale of the dimensions is sometimes different depending on the constituent elements so as to facilitate observation of each constituent element.

[0032] The projector 10 of this embodiment is a projection-type image display device that displays color images on a screen (projected surface) SCR. The projector 10 has three light modulation devices corresponding to each color light: red light LR, green light LG, and blue light LB.

[0033] Figure 1 This is a schematic structural diagram of the projector 10 according to this embodiment.

[0034] like Figure 1 As shown, the projector 10 includes a light source device 100, a color separation light guiding optical system 200, a red light modulation device 400R, a green light modulation device 400G, a blue light modulation device 400B, a cross-shaped color separation prism 500, and a projection optical device 600.

[0035] In this embodiment, the light source device 100 emits a white composite light LW comprising red light LR, green light LG, and blue light LB. The specific structure of the light source device 100 will be described later.

[0036] The color separation light guiding optical system 200 includes a dichroic mirror 210, a dichroic mirror 220, a reflector 230, a reflector 240, a reflector 250, a relay lens 260, and a relay lens 270. The color separation light guiding optical system 200 separates the composite light LW emitted from the light source device 100 into red light LR, green light LG, and blue light LB. The red light LR is guided to the red light modulation device 400R, the green light LG is guided to the green light modulation device 400G, and the blue light LB is guided to the blue light modulation device 400B.

[0037] A field lens 300R is disposed between the color-separated light-guiding optical system 200 and the red light modulation device 400R. A field lens 300G is disposed between the color-separated light-guiding optical system 200 and the green light modulation device 400G. A field lens 300B is disposed between the color-separated light-guiding optical system 200 and the blue light modulation device 400B.

[0038] Dichroic mirror 210 allows red light to pass through while reflecting green and blue light. Dichroic mirror 220 reflects green light while allowing blue light to pass through. Mirror 230 reflects red light. Mirrors 240 and 250 reflect blue light respectively.

[0039] The red light modulation device 400R, the green light modulation device 400G, and the blue light modulation device 400B are each composed of a liquid crystal panel that modulates the colored light incident on each light modulation device according to image information to form an image.

[0040] Although the illustrations are omitted, incident-side polarizers are disposed between field lens 300R and red light modulation device 400R, between field lens 300G and green light modulation device 400G, and between field lens 300B and blue light modulation device 400B. Furthermore, exit-side polarizers are disposed between red light modulation device 400R and cross-shaped dichroic prism 500, between green light modulation device 400G and cross-shaped dichroic prism 500, and between blue light modulation device 400B and cross-shaped dichroic prism 500.

[0041] The cross-shaped dichroic prism 500 combines the image lights emitted from the red light modulation device 400R, the green light modulation device 400G, and the blue light modulation device 400B respectively to form a color image. The cross-shaped dichroic prism 500 is roughly square in shape when viewed from above, formed by bonding four right-angled prisms together, and has a structure in which a dielectric multilayer film is provided at the roughly X-shaped interface formed by bonding the right-angled prisms together.

[0042] The color image emitted from the cross-shaped dichroic prism 500 is magnified by the projection optics 600 and projected onto a projection surface such as a screen SCR. The projection optics 600 consists of multiple lenses.

[0043] Figure 2 This is a schematic structural diagram of the light source device 100.

[0044] In the following description, an XYZ orthogonal coordinate system is used as the coordinate axes. The direction in which the composite light LW is emitted from the light source device 100 is set as the positive direction of the Y-axis, the direction in which the blue light is emitted from the first light source unit 11 (described later) is set as the positive direction of the X-axis, and the direction perpendicular to the X-axis and Y-axis and moving from the front of the paper toward the inside is set as the positive direction of the Z-axis.

[0045] The light source device 100 of this embodiment includes a first light source unit 11, a second light source unit 12, a wavelength conversion element 13, a light combining element 14, a filter 15, a parallelization element 16, a diffusion device 17, a focusing element 18, a focusing / pickup element 19, a second phase difference plate 20, an integrator optical element 21, a polarization conversion element 22, an overlapping lens 23, and a control unit 24.

[0046] The first light source unit 11 includes a first light-emitting element 27, a collimating lens 28, and a first phase retardation plate 29. The first light-emitting element 27 is composed of a blue semiconductor laser that emits linearly polarized blue light (LBs). The first light-emitting element 27 emits blue light (LBs) in a first wavelength band in the +X direction. The first wavelength band is, for example, a blue wavelength band of 455 nm ± 10 nm. The first light-emitting element 27 is mounted on a substrate 30. Figure 2 The diagram shows two first light-emitting elements 27, but the number of first light-emitting elements 27 is not particularly limited. In this embodiment, the blue light LBs emitted from the first light-emitting elements 27 is S-polarized light relative to the light-combining element 14, but it can also be P-polarized light LBp relative to the light-combining element 14. In the following description, unless otherwise specified, the terms S-polarized light and P-polarized light refer to the polarization direction relative to the light-combining element 14.

[0047] In this embodiment, the blue light LBs and LBp correspond to the first light in the technical solution.

[0048] A collimating lens 28 is disposed on the light-emitting side of the first light-emitting element 27. The collimating lens 28 is composed of a convex lens disposed corresponding to one of the first light-emitting elements 27. The collimating lens 28 parallelizes the blue light LBs emitted from the first light-emitting element 27.

[0049] A first phase difference plate 29 is disposed in the optical path of the blue light LBs between the first light-emitting element 27 and the light-combining element 14. The first phase difference plate 29 imparts a phase difference to the blue light LBs. The first phase difference plate 29 is constructed of a plate with a wavelength of 1 / 2 wavelength relative to the first band of the blue light LBs. The first phase difference plate 29 is configured to be rotatable about an axis orthogonal to the light incident surface 29a (an axis parallel to the X-axis). Therefore, a drive source such as a motor (not shown) is provided in the first phase difference plate 29.

[0050] The blue light LBs emitted from the first light-emitting element 27 is linearly polarized light (S-polarization component). Therefore, by appropriately setting the rotation angle of the first phase retardation plate 29, the blue light LBs transmitted through the first phase retardation plate 29 can be converted into blue light containing S-polarization and P-polarization components at a predetermined ratio. That is, by rotating the first phase retardation plate 29, the ratio of the S-polarization component to the P-polarization component can be changed. In this way, the first light source 11 emits blue light LBs and LBp in the first band containing S-polarization and P-polarization components. The optical path of the principal rays of the blue light LBs and LBp emitted from the first light source 11 is defined as the optical axis AX1 of the first light source 11.

[0051] The first phase difference plate 29 in this embodiment corresponds to the first phase difference element in the technical solution. The S-polarization component in this embodiment corresponds to the first polarization component in the technical solution. The P-polarization component in this embodiment corresponds to the second polarization component in the technical solution.

[0052] The second light source unit 12 includes a second light-emitting element 32 and a collimating lens 33. The second light-emitting element 32 is composed of a red semiconductor laser that emits linearly polarized red light (LR). The second light-emitting element 32 emits red light (LR) in a second wavelength band in the +Y direction. The second wavelength band is, for example, a red wavelength band of 640 nm ± 10 nm. The second light-emitting element 32 is mounted on a substrate 34. Figure 2 The diagram shows two second light-emitting elements 32, but the number of second light-emitting elements 32 is not particularly limited. The red light LR emitted from the second light-emitting elements 32 can be either S-polarized or P-polarized. The optical path of the principal ray of the red light LR emitted from the second light source unit 12 is defined as the optical axis AX2 of the second light source unit 12.

[0053] The red light LR in this embodiment corresponds to the second light in the technical solution.

[0054] The wavelength conversion element 13 includes a green phosphor that absorbs blue light LBp and converts it into green light LG for emission. That is, the wavelength conversion element 13 converts the blue light LBp emitted from the first light source 11 into green light LG in the third wavelength band and emits the green light LG in the -X direction. The third wavelength band is, for example, the green wavelength band of 470 nm to 650 nm. The wavelength conversion element 13 includes, for example, Lu3Al5O4. 12 Ce 3+ System phosphor, Y3O4:Eu 2+ System phosphor, (Ba,Sr)2SiO4:Eu 2+ Phosphor, Ba3Si6O 12 N2: Eu 2+ System phosphor, (Si,Al)6(O,N)8:Eu 2+ A phosphor material such as a phosphor is used as a green phosphor. A wavelength conversion element 13 is disposed on a substrate (not shown). Alternatively, the wavelength conversion element 13 can be disposed in a ring shape around a rotation axis on a rotatable substrate. This structure can suppress temperature rise of the wavelength conversion element 13, improve wavelength conversion efficiency, and enhance the reliability of the wavelength conversion element 13.

[0055] In this embodiment, the green light LG corresponds to the third light in the technical solution.

[0056] The light-combining element 14 is positioned at the intersection of the optical axis AX1 of the first light source unit 11 and the optical axis AX2 of the second light source unit 12. The light-combining element 14 includes a substrate 36, a third optical film 37 disposed on one side of the substrate 36, and a fourth optical film 38 disposed on the other side of the substrate 36. The third optical film 37 and the fourth optical film 38 are each composed of a dielectric multilayer film. The light-combining element 14 is configured to face at 45-degree angles relative to both the optical axes AX1 and AX2.

[0057] The light combining element 14, through the action of the third optical film 37 and the fourth optical film 38, reflects the S-polarized blue light LBs from the first light source 11 and allows the P-polarized blue light LBp to pass through. As a result, the P-polarized blue light LBp is emitted towards the wavelength conversion element 13, the S-polarized blue light LBs is emitted towards the diffusion device 17, and both blue light LBp and red light LR are transmitted, while green light LG is reflected. Thus, the light combining element 14 combines the blue light LBp incident from the diffusion device 17 along the +Y direction, the red light LR incident from the second light source 12 along the +Y direction, and the green light LG incident from the wavelength conversion element 13 along the -X direction, emitting white combined light LW towards the +Y direction. The detailed spectral characteristics of each optical film 37 and 38 will be described later.

[0058] In this embodiment, the -X direction corresponds to the first direction of the technical solution. In this embodiment, the +Y direction corresponds to the second direction of the technical solution.

[0059] A filter 15 is disposed on the optical axis AX2 between the light combining element 14 and the integrator optical element 21. In this embodiment, the filter 15 is configured such that the light incident surface 15a of the filter 15 intersects the optical path of the main ray of the combined light LW containing green light LG at a 90-degree angle. The filter 15 has a substrate 40, a first optical film 41 disposed on one side of the substrate 40, and a second optical film 42 disposed on the other side of the substrate 40. The first optical film 41 and the second optical film 42 are each composed of a dielectric multilayer film.

[0060] The filter 15 is movable in a direction perpendicular to the optical path (optical axis AX2) of the main ray of the composite light LW (X-axis direction). That is, the filter 15 can move between a first position (shown as a solid line) where the composite light LW containing green light LG passes through the filter 15 and a second position (shown as a dashed line) where the composite light LW containing green light LG does not pass through the filter 15. The filter 15 can have a structure that automatically moves via a drive source such as a motor (not shown) when the user selects either a color reproduction emphasis mode or a brightness emphasis mode, or it can have a structure that allows the user to move it manually. When the filter 15 is located at the first position where the composite light LW containing green light LG is incident, the first optical film 41 and the second optical film 42 reduce the green light LG in a portion of the third band (green band). The detailed spectral characteristics of each optical film 41 and optical film 42 will be described later.

[0061] The parallelizing element 16 is disposed on the optical axis AX1 between the wavelength conversion element 13 and the light combining element 14. In this embodiment, the parallelizing element 16 is composed of two convex lenses, but the number of lenses is not particularly limited. The parallelizing element 16 parallelizes the green light LG emitted from the wavelength conversion element 13 and converges the blue light LBp emitted from the light combining element 14 toward the wavelength conversion element 13.

[0062] A diffusion device 17 is disposed on the optical axis AX2 between the light combining element 14 and the second light source unit 12. The diffusion device 17 includes a diffusion plate 44 and a motor 46 that rotates the diffusion plate 44 around a rotation axis 45. Although not shown in the figure, a concave-convex structure is provided on one side of the diffusion plate 44 as a diffusion structure to diffuse the blue light LBc1 and red light LR incident on the diffusion plate 44. The concave-convex structure can be a structure with multiple concave and convex portions having irregular shapes and sizes, or it can be a structure with multiple microlenses arranged thereon. In addition, a reflective film, i.e., a dichroic film, is provided on the other side of the diffusion plate 44 to reflect the blue light component and allow the red light component to pass through. In addition, as other types of diffusion plate 44, frosted glass, holographic diffusers, transparent substrates that have undergone sandblasting treatment, transparent substrates with dispersed scattering materials, etc., can also be used.

[0063] Thus, the light source device 100 of this embodiment includes a diffusion device 17 for diffusing blue light LBc1 and red light LR. With this structure, the illuminance distribution of blue light LBc1 and red light LR can be homogenized, reducing color unevenness. Furthermore, since the coherent light emitted from the semiconductor laser, namely blue light LBc1 and red light LR, is diffused, speckle noise in the image applied to the projector 10 can be suppressed. Moreover, since separate diffusion devices for diffusing blue light LBc1 and red light LR are not required, the number of components in the light source device 100 can be reduced and miniaturized. Furthermore, since the diffusion device 17 is provided on the optical axis AX2 between the light combining element 14 and the second light source unit, it is possible to prevent the light source device 100 from becoming too large in the direction intersecting the optical axis AX2 between the integrator optical element 21 and the second light source unit 12.

[0064] A focusing element 18 is disposed on the optical axis AX2 between the second light source 12 and the diffuser plate 44. In this embodiment, the focusing element 18 is composed of two convex lenses, but the number of lenses is not particularly limited. The focusing element 18 focuses the red light LR emitted from the second light source 12 toward the diffuser plate 44.

[0065] A focusing / pickup element 19 is disposed on the optical axis AX2 between the diffuser plate 44 and the light combining element 14. In this embodiment, the focusing / pickup element 19 is composed of two convex lenses, but the number of lenses is not particularly limited. The focusing / pickup element 19 converges the blue light LBc1 emitted from the light combining element 14 toward the diffuser plate 44, and parallelizes the blue light LBc2 and red light LR diffused by the diffuser plate 44.

[0066] The second phase retardation plate 20 is disposed on the optical axis AX2 between the focusing / picking element 19 and the light combining element 14. The second phase retardation plate 20 imparts a phase difference to the blue light LBs and LBc2. The second phase retardation plate 20 is constructed of a 1 / 4 wavelength plate relative to the first band of the blue light LBs and LBc2. Thus, the linearly polarized blue light LBs passing through the second phase retardation plate 20 is converted into circularly polarized blue light LBc1, and the circularly polarized blue light LBc2 passing through the second phase retardation plate 20 is converted into linearly polarized blue light LBp.

[0067] The integrator optics 21 has a first multi-lens array 48 and a second multi-lens array 49. The first multi-lens array 48 has a plurality of first lenses for splitting the synthesized light LW into multiple beams.

[0068] The lens surface of the first multi-lens array 48, i.e., the surface of the first lens, is conjugate with the image forming areas of the light modulation devices 400R, 400G, and 400B for each color of light. Therefore, when viewed from the optical axis AX2, the shape of each of the first lenses is rectangular, roughly similar to the shape of the image forming areas of the light modulation devices 400R, 400G, and 400B. Thus, multiple light beams emitted from the first multi-lens array 48 are efficiently incident on the image forming areas of the light modulation devices 400R, 400G, and 400B, respectively.

[0069] The second multi-lens array 49 has a plurality of second lenses corresponding to the plurality of first lenses of the first multi-lens array 48. Together with the overlapping lens 23, the second multi-lens array 49 enables the images of each first lens of the first multi-lens array 48 to be imaged near the respective image forming areas of each optical modulation device 400R, 400G, 400B.

[0070] The synthesized light LW, passing through the integrator optical element 21, is incident on the polarization conversion element 22. The polarization conversion element 22 has a structure in which a polarization separation film (not shown), a reflective film, and a retardation plate are arranged in an array. The polarization conversion element 22 aligns the polarization direction of the synthesized light LW with a predetermined direction. Specifically, the polarization conversion element 22 aligns the polarization direction of the synthesized light LW with the transmission axis direction of the incident-side polarizer of the optical modulation devices 400R, 400G, and 400B.

[0071] Therefore, the polarization directions of the red light LR, green light LG, and blue light LB separated from the synthesized light LW that has passed through the polarization conversion element 22 are aligned with the transmission axis direction of the incident-side polarizers of the optical modulation devices 400R, 400G, and 400B. Consequently, the red light LR, green light LG, and blue light LB are not absorbed by the incident-side polarizers, but instead are incident on the image forming areas of the optical modulation devices 400R, 400G, and 400B, respectively.

[0072] The synthesized light LW, which has passed through the polarization conversion element 22, is incident on the overlapping lens 23. The overlapping lens 23, in cooperation with the integrator optical element 21, homogenizes the illuminance distribution in the image forming areas of the light modulation devices 400R, 400G, and 400B, which are the illuminated areas.

[0073] The control unit 24 controls the current values ​​supplied to the first light-emitting element 27 of the first light source unit 11 and the second light-emitting element 32 of the second light source unit 12, respectively. Specifically, the control unit 24 individually controls the current values ​​supplied to the first light source unit 11 and the second light source unit 12 when the filter 15 is positioned in the first position, and the current values ​​supplied to the first light source unit 11 and the second light source unit 12 when the filter 15 is positioned in the second position. Specific examples of the control will be described later. Furthermore, the control unit 24 can also control items such as the movement of the filter 15, the rotation angle of the first phase difference plate 29, and the rotation speed of the diffuser plate 44 when either the color reproduction emphasis mode or the brightness emphasis mode is selected.

[0074] The operation of the light emitted from the first light source unit 11 and the second light source unit 12 will be explained below.

[0075] As described above, in the first light source unit 11, the S-polarized blue light LBs emitted from the first light-emitting element 27 passes through the first phase difference plate 29, thereby being converted into blue light LBs and LBp, which are a mixture of S-polarized and P-polarized components in a predetermined ratio. The P-polarized blue light LBp passes through the light combining element 14 and is incident on the wavelength conversion element 13 in a state where it is converged by the parallelizing element 16. In the wavelength conversion element 13, the green phosphor is excited by the blue light LBp and emits green light LG. The green light LG emitted from the wavelength conversion element 13 is parallelized by the parallelizing element 16 and reflected by the light combining element 14, traveling towards the filter 15.

[0076] On the other hand, the S-polarized blue light LBs is reflected by the light combining element 14 and passes through the second phase difference plate 20, thereby being converted into a predetermined circularly polarized, for example, right-hand circularly polarized blue light LBc1. The right-hand circularly polarized blue light LBc1 is incident on the diffuser plate 44 in a state of being focused by the light-collecting element 19. The right-hand circularly polarized blue light LBc1 incident on the diffuser plate 44 is diffused by the diffuser plate 44 and converted into left-hand circularly polarized blue light LBc2. After being parallelized by the light-collecting element 19, the left-hand circularly polarized blue light LBc2 passes through the second phase difference plate 20, thereby being converted into a P-polarized blue light LBp. The P-polarized blue light LBp passes through the light combining element 14 and travels toward the filter 15.

[0077] In the second light source unit 12, red light LR emitted from the second light-emitting element 32 is focused by the focusing element 18 and incident on the diffuser plate 44, where it is diffused. After being parallelized by the focusing / pickup element 19, the diffused red light LR passes through the second phase retardation plate 20, then through the light combining element 14, and travels toward the filter 15. Furthermore, the second phase retardation plate 20 is optimized for the blue band; therefore, even if the red light LR passes through the second phase retardation plate 20, its polarization state does not change significantly. Moreover, the light combining element 14 allows the red light LR to pass through regardless of its polarization state.

[0078] As described above, blue light LBp, green light LG, and red light LR are synthesized by the light synthesizing element 14. White synthesized light LW is emitted from the light synthesizing element 14.

[0079] The following describes the spectral characteristics of each optical film in the filter 15 and the photosynthesizing element 14. Figure 3 This is a graph showing the spectral characteristics of the first optical film 41 of the filter 15. Figure 4 This is a graph showing the spectral characteristics of the second optical film 42 of filter 15. Figure 5 This is a graph showing the spectral characteristics of the third optical film 37 of the photosynthesizing element 14. Figure 6 This is a graph showing the spectral dispersive characteristics of the fourth optical film 38 of the light-synthesizing element 14. Figures 3-6 In the figure, the horizontal axis represents wavelength (nm) and the vertical axis represents transmittance (%).

[0080] Figure 8 It is a chart showing the emission spectrum of each light source part 11, 12. Figure 9 This is a graph showing the spectrum of green light LG after passing through filter 15. Figure 8 and Figure 9 In the figure, the horizontal axis represents wavelength (nm) and the vertical axis represents relative brightness (-).

[0081] like Figure 8 As shown, the first light-emitting element 27 of the first light source unit 11 emits blue light LBs in the blue band at 455nm ± 10nm. The second light-emitting element 32 of the second light source unit 12 emits red light LR in the red band at 640nm ± 10nm. The wavelength conversion element 13 emits green light LG in the green band at 470nm to 650nm.

[0082] Regarding the emission spectrum mentioned above, such as Figure 3As shown, the first optical film 41 of the filter 15 blocks the short-wavelength components (approximately 470nm to 520nm) of the green light LG emitted from the wavelength conversion element 13, while allowing the remaining wavelength components to pass through. Furthermore, the first optical film 41 allows the blue light LBp (center wavelength 455nm) and the red light LR (center wavelength 640nm) to pass through. Thus, the first optical film 41 helps to block the short-wavelength components of the green light LG.

[0083] like Figure 4 As shown, the second optical film 42 of the filter 15 blocks the long-wavelength components (approximately 540nm to 620nm) of the green light LG emitted from the wavelength conversion element 13, while allowing the remaining wavelength components to pass through. Furthermore, the second optical film 42 allows the blue light LBp (center wavelength 455nm) and the red light LR (center wavelength 640nm) to pass through. Thus, the second optical film 42 helps to block the long-wavelength components of the green light LG.

[0084] Through the action of the two optical films 41 and 42, the filter 15 blocks the short-wavelength components (470nm-520nm) and long-wavelength components (540nm-620nm) of the third-band green light LG emitted from the wavelength conversion element 13 (470nm-650nm). Thus, as... Figure 9 As shown, filter 15 can narrow the wavelength of green light LG to about 530nm±20nm.

[0085] like Figure 5 As shown, the third optical film 37 of the light combining element 14 allows the P-polarized component of the blue light LBs and LBp in the first band to pass through, while reflecting the S-polarized component. Additionally, the third optical film 37 allows the red light LR in the second band and the green light LG in the third band to pass through. Thus, the third optical film 37 functions as a polarization separation film for the blue light LBs and LBp.

[0086] like Figure 6 As shown, the fourth optical film 38 of the light combining element 14 allows blue light LBp of the first band to pass through, reflects green light LG of the third band to reflect, and allows red light LR of the second band to pass through. Furthermore, the fourth optical film 38 allows the longer wavelength components of the green light LG of the third band to pass through. Thus, the fourth optical film 38 functions as a wavelength-selective film.

[0087] Through the action of the two optical films 37 and 38, the light combining element 14 can achieve the following functions: allowing the P-polarized blue light LBp of the blue light LBs and LBp emitted from the first light source 11 to pass through, allowing the S-polarized blue light LBs to reflect, allowing the red light LR to pass through, and allowing the green light LG to reflect.

[0088] Alternatively, filter 15 can have the following structure instead of the structure described above.

[0089] Figure 7 This is a graph showing the spectral characteristics of the first optical film of the modified filter.

[0090] Although the illustration is omitted, the modified filter has a substrate, a first optical film disposed on one side of the substrate, and an anti-reflective film disposed on the other side of the substrate.

[0091] like Figure 7 As shown, in the modified example, the first optical film of the filter only allows the 520nm to 550nm component of the green light LG in the 470nm to 650nm wavelength band emitted from the wavelength conversion element 13 to pass through. Additionally, the first optical film allows the blue light LBp with a center wavelength of 455nm and the red light LR with a center wavelength of 640nm to pass through.

[0092] As explained above, the green light LG contained in the synthesized light LW emitted from the light-combining element 14 passes through the filter 15, thereby narrowing the band and improving color purity. On the other hand, the blue light LBp and red light LR, which are originally narrow-band light from the semiconductor laser, maintain high color purity even after passing through the filter 15. Therefore, if the filter 15 is arranged within the optical path of the synthesized light LW, the color gamut of the synthesized light LW is expanded, thus improving color reproducibility. Conversely, if the filter 15 is arranged outside the optical path of the synthesized light LW, a portion of the green light LG will not be blocked by the filter 15, thus increasing the brightness of the synthesized light LW.

[0093] The light source device 100 of this embodiment includes a parallelizing element 16 disposed on the light incident side of the filter 15, which parallelizes the green light LG emitted from the wavelength conversion element 13. Furthermore, the light source device 100 includes a focusing / picking element 19 disposed on the light incident side of the filter 15, which parallelizes the blue light LBc2 and red light LR emitted from the diffuser plate 44. Additionally, the filter 15 is configured such that its light incident surface 15a intersects the optical path of the composite light LW containing the green light LG at a 90-degree angle. With this structure, the composite light LW is incident perpendicularly to the light incident surface 15a of the filter 15. Therefore, the design of the optical films 41 and 42 of the filter 15 does not require consideration of the angle of incidence, thus easily improving the characteristics of the filter 15 and facilitating its manufacture.

[0094] The following describes a specific example of how the control unit 24 controls the current values ​​of each light source unit 11 and 12.

[0095] In the inventor's research, the color temperature of a projector using a specific optical system was set to 6500K, and the deviation was set to 0.003. If the color gamut meets the standard DCI-P3 when the filter 15 is not in the optical path, the balance of light intensity of each color used to ensure the specified white balance is red light: green light: blue light = 160%: 100%: 58%.

[0096] Next, to improve color reproducibility, filter 15 is placed inside the optical path. At this time, a portion of the green light LG is blocked by filter 15, thus reducing the amount of green light LG. In this case, to ensure the same white balance as when filter 15 is not placed inside the optical path, the amounts of red light LR and blue light LBp need to be reduced accordingly to the reduction in the amount of green light LG. Therefore, the light balance when filter 15 is placed inside the optical path is red light: green light: blue light = 75%: 100%: 15.9%.

[0097] Thus, when the filter 15 is in the optical path, the balance between the amount of green light LG and blue light LBp never changes because the filter 15 is in the optical path. Therefore, by rotating the first phase difference plate 29, the ratio of the amount of P-polarized components to S-polarized components is changed, thereby adjusting the balance between the amount of green light LG and blue light LBp. Furthermore, when the filter 15 is in the optical path, the balance between the amount of green light LG and red light LR also never changes because the filter 15 is in the optical path. Therefore, the control unit 24 performs control such that the current value supplied to the second light-emitting element 32 when the filter 15 is in the optical path is less than the current value supplied to the second light-emitting element 32 when the filter 15 is not in the optical path.

[0098] Here, when the light source device 100 has a structure that distributes current from one power source to the first light-emitting element 27 and the second light-emitting element 32, when the current value supplied to the second light-emitting element 32 is reduced, the power capacity of the power source becomes larger, allowing more current to be supplied to the first light-emitting element 27. At this time, the control unit 24 performs control such that the current value supplied to the first light-emitting element 27 when the filter 15 is in the optical path is greater than the current value supplied to the first light-emitting element 27 when the filter 15 is not in the optical path.

[0099] In the light source device 100 of this embodiment, the white balance of the synthetic light LW emitted from the light source device 100 can be adjusted by the control unit 24, and the reduction in brightness when the filter 15 enters the light path can be minimized.

[0100] The following uses Figure 10 as well as Figure 11 The preferred direction of movement of filter 15 will be explained.

[0101] Figure 10 This is a graph showing the relationship between the illuminance distribution of blue light LBp on filter 15 and the direction of movement of filter 15. Figure 11 This is a graph showing the relationship between the illuminance distribution of green light LG on filter 15 and the direction of movement of filter 15.

[0102] Typically, the cross-sectional shape of light emitted from a semiconductor laser is an ellipse with a major axis and a minor axis. In this specification, the cross-sectional shape of light is defined as the cross-sectional shape in the direction perpendicular to the principal ray of the light. Therefore, in this embodiment, in most cases, although the cross-sectional shape of the blue light LBp incident on the filter 15 varies slightly depending on the number and arrangement of the first light-emitting elements 27, it will not become circular even after being diffused by the diffuser plate 44. Figure 10 Maintain the elliptical shape as shown.

[0103] On the other hand, green light LG is isotropically emitted from wavelength conversion element 13 as a Lambertian emission, therefore, as Figure 11 As shown, the cross-sectional shape of the green light LG incident on filter 15 largely maintains a circular shape. Furthermore, to suppress color unevenness in the subsequent optical system of filter 15, the length D1 of the diameter in the cross-sectional shape of the green light LG is made approximately the same as either the length D2 of the diameter along the major axis or the length D3 of the diameter along the minor axis in the cross-sectional shape of the blue light LBp. Figure 10 and Figure 11 In the example, the length D1 of the diameter in the cross-sectional shape of the green light LG is approximately the same as the length D2 of the diameter along the major axis in the cross-sectional shape of the blue light LBp. Conversely, the length D1 of the diameter in the cross-sectional shape of the green light LG can also be approximately the same as the length D3 of the diameter along the minor axis in the cross-sectional shape of the blue light LBp.

[0104] like Figure 10 and Figure 11As shown, filter 15 is moved along the short axis (horizontal direction in the figure) of the cross-sectional shape of blue light LBp. In this case, as shown on the right side of the figure, during the movement of filter 15, the following occurs: blue light LBp passes through filter 15 in all areas, while green light LG does not pass through filter 15 in some areas. Therefore, color unevenness may occur during the movement of filter 15 when switching modes. Therefore, if filter 15 is moved along the long axis (vertical direction in the figure) of the cross-sectional shape of blue light LBp, the situation where one light passes through filter 15 in all areas and the other light does not pass through filter 15 in some areas will not occur. Thus, color unevenness during the movement of filter 15 can be suppressed. That is, when the length of the diameter D1 in the cross-sectional shape of the green light LG is approximately the same as either the length of the diameter D2 along the long axis or the length of the diameter D3 along the short axis in the cross-sectional shape of the blue light LBp, it is preferable to move the filter 15 in a direction that is approximately the same along the long axis and the short axis.

[0105] [Effects of the first embodiment]

[0106] The light source device 100 of this embodiment includes: a first light source unit 11 that emits blue light LBs and LBp of a first band containing S-polarization and P-polarization components; a second light source unit 12 that emits red light LR of a second band; a wavelength conversion element 13 that converts blue light LBp into green light LG of a third band; a light combining element 14 that combines blue light LBp, red light LR, and green light LG to emit combined light LW; and a filter 15 that reduces the light in a portion of the third band when green light LG is incident. The light combining element 14 reflects the S-polarized blue light LBs of the blue light LBs and LBp emitted from the first light source unit 11 and transmits the P-polarized blue light LBp, thereby emitting the P-polarized blue light LBp toward the wavelength conversion element 13, emitting the S-polarized blue light LBs toward the diffusion device 17, allowing the blue light LBp and red light LR to pass through, and reflecting the green light LG. The filter 15 can move between a first position where the green light LG passes through the filter 15 and a second position where the green light LG does not pass through the filter 15.

[0107] According to this structure, as described above, at the first position where the green light LG passes through the filter 15, a portion of the wavelength of the green light LG is attenuated, thereby narrowing the green light LG and improving color purity. This widens the color gamut of the synthesized light LW, improving color reproducibility. On the other hand, at the second position where the green light LG does not pass through the filter 15, a portion of the wavelength of the green light LG is not attenuated by the filter 15, thus increasing the brightness of the synthesized light LW. In this way, by moving the filter 15 between the first and second positions, the characteristics of the synthesized light LW emitted from the light source device 100 can be changed. As a result, when the light source device 100 is applied to the projector 10, the color reproducibility emphasis mode and the brightness emphasis mode can be switched by moving the filter 15.

[0108] The projector 10 of this embodiment includes: a light source device 100 of this embodiment; light modulation devices 400R, 400G, and 400B, which modulate light including synthetic light LW emitted from the light source device 100 according to image information; and a projection optical device 600, which projects light modulated by the light modulation devices 400R, 400G, and 400B.

[0109] According to this structure, the color reproduction emphasis mode and the brightness emphasis mode can be switched by the light source device 100. Therefore, the projector 10 can be used by the user to distinguish between purposes such as improving the performance of images to watch movies and purposes such as displaying data in a bright room.

[0110] [Second Implementation]

[0111] The following uses Figure 12 The second embodiment of the present invention will be described.

[0112] The basic structure of the projector in the second embodiment is the same as that in the first embodiment, but the structure of the light source device is different from that in the first embodiment. Therefore, the description of the basic structure of the projector is omitted.

[0113] Figure 12 This is a schematic structural diagram of the light source device 120 according to the second embodiment.

[0114] exist Figure 12 In the first embodiment, for use with Figure 2 The same constituent elements are labeled with the same reference numerals, and the descriptions are omitted.

[0115] like Figure 12As shown, the light source device 120 of this embodiment includes a first light source unit 11, a second light source unit 12, a wavelength conversion element 13, a light combining element 14, a filter 15, a parallelization element 16, a diffusion device 17, a focusing element 18, a focusing / pickup element 19, a second phase difference plate 20, an integrator optical element 21, a polarization conversion element 22, an overlapping lens 23, and a control unit 24.

[0116] In the first embodiment, the filter 15 is configured such that the light incident surface 15a intersects the optical path of the main ray of the composite light LW containing the green light LG at a 90-degree angle. In contrast, in this embodiment, the filter 15 is obliquely configured such that the light incident surface 15a intersects the optical path (optical axis AX2) of the main ray of the composite light LW containing the green light LG at an angle other than 90 degrees. The other structures of the light source device 120 are the same as in the first embodiment.

[0117] [Effects of the second implementation method]

[0118] In the light source device 120 of this embodiment, the characteristics of the composite light LW emitted from the light source device 120 can also be changed by moving the filter 15 between the first position and the second position. When applied to the projector 10, the same effect as in the first embodiment can be obtained, such as the ability to switch between color reproduction emphasis mode and brightness emphasis mode.

[0119] Furthermore, in this embodiment, the light incident surface 15a of the filter 15 is tilted at an angle of more than 90 degrees to intersect the optical path of the composite light LW containing the green light LG. According to this structure, a portion of the composite light LW reflected by the filter 15 travels on a different path than the composite light LW incident on the filter 15. Therefore, the amount of light returning to the wavelength conversion element 13 and each of the light-emitting elements 27, 32 after being reflected by the filter 15 can be reduced. This improves the reliability of the wavelength conversion element 13 and each of the light-emitting elements 27, 32. For example, the structure can be configured such that light traveling toward the wavelength conversion element 13 is incident on the support substrate of the wavelength conversion element 13. With this structure, heat generated by reflected light can be released from the support substrate, further improving the reliability of the wavelength conversion element 13.

[0120] [Third Implementation]

[0121] The following uses Figure 13 as well as Figure 14 The third embodiment of the present invention will be described.

[0122] The basic structure of the projector in the third embodiment is the same as that in the first embodiment, but the structure of the light source device is different from that in the first embodiment. Therefore, the description of the basic structure of the projector is omitted.

[0123] Figure 13 This is a schematic structural diagram of the light source device 130 according to the third embodiment.

[0124] exist Figure 13 In the first embodiment, for use with Figure 2 The same constituent elements are labeled with the same reference numerals, and the descriptions are omitted.

[0125] like Figure 13 As shown, the light source device 130 of this embodiment includes a first light source unit 11, a second light source unit 12, a wavelength conversion element 13, a light combining element 14, a filter 55, a parallelization element 16, a diffusion device 17, a focusing element 18, a focusing / pickup element 19, a second phase difference plate 20, an integrator optical element 21, a polarization conversion element 22, an overlapping lens 23, and a control unit 24.

[0126] The position of the filter 55 in the light source device 130 of this embodiment differs from that in the light source device 100 of the first embodiment. Specifically, in this embodiment, the filter 55 is disposed on the optical axis AX1 between the light combining element 14 and the wavelength conversion element 13. In the first embodiment, the synthesized light LW, i.e., all colors of light, synthesized by the light combining element 14, is incident on the filter 55. In contrast, in this embodiment, the green light LG before synthesis by the light combining element 14 and the blue light LBp emitted from the light combining element 14 are incident on the filter 55, while the red light LR is not incident on the filter 55. The other structures of the light source device 130 are the same as in the first embodiment.

[0127] Figure 14 This is a graph showing the spectral dispersive characteristics of the second optical film 56 of the filter 55 in this embodiment. Figure 14 In the figure, the horizontal axis represents wavelength (nm) and the vertical axis represents transmittance (%).

[0128] like Figure 14 As shown, the second optical film 56 of the filter 55 blocks components of the green light LG emitted from the wavelength conversion element 13 that have a longer wavelength than 550 nm. Additionally, the first optical film 41 is the same as the first optical film 41 of the first embodiment (see reference 1). Figure 3 The same applies. Through the action of two optical films 56 and 41, the filter 55 blocks the short wavelength components of 470nm to 520nm and the long wavelength components above 550nm in the third band of green light (470nm to 650nm) emitted from the wavelength conversion element 13. Thus, the filter 55 can narrow the green light LG.

[0129] [Effects of the third embodiment]

[0130] In the light source device 130 of this embodiment, the characteristics of the composite light LW emitted from the light source device 130 can also be changed by moving the filter 55 between the first position and the second position. When applied to the projector 10, the same effect as in the first embodiment can be obtained, such as the ability to switch between color reproduction emphasis mode and brightness emphasis mode.

[0131] In this embodiment, the second optical film 42 of the first embodiment can also be used as the second optical film of the filter 55, but it is preferable to use the one described above. Figure 14 The second optical film 56 is shown to exhibit spectral dispersion characteristics. According to this structure, the second optical film 56 does not need to block the long-wavelength component of green light LG and allows red light LR to pass through; therefore, the specifications of the second optical film 56 are superior. Figure 4 The second optical film 42 of the first embodiment shown has simple specifications. Therefore, the manufacturing cost of the filter 55 can be reduced, and the desired spectral characteristics can be easily achieved.

[0132] [Fourth Implementation]

[0133] The following uses Figure 15 as well as Figure 16 The fourth embodiment of the present invention will be described.

[0134] The basic structure of the projector in the fourth embodiment is the same as that in the first embodiment, but the structure of the light source device is different from that in the first embodiment. Therefore, the description of the basic structure of the projector is omitted.

[0135] Figure 15 This is a schematic structural diagram of the light source device 140 according to the fourth embodiment.

[0136] exist Figure 15 In the first embodiment, for use with Figure 2 The same constituent elements are labeled with the same reference numerals, and the descriptions are omitted.

[0137] like Figure 15 As shown, the light source device 140 of this embodiment includes a first light source unit 11, a second light source unit 12, a wavelength conversion element 13, a light combining element 64, a filter 15, a parallelization element 16, a diffusion device 65, a focusing element 18, a focusing / picking element 19, a second phase difference plate 20, an integrator optical element 21, a polarization conversion element 22, an overlapping lens 23, and a control unit 24. In the light source device 140 of this embodiment, the structure of the light combining element 64, the position of the second light source unit 12, and the structure of the diffusion device 65 are different from those of the light source device 100 of the first embodiment.

[0138] In this embodiment, the light-combining element 64 is composed of a first light-combining element 67 and a second light-combining element 68. The structure and optical characteristics of the first light-combining element 67 are the same as those of the light-combining element 14 in the first embodiment. Furthermore, the positional relationship between the first light source 11, the wavelength conversion element 13, and the diffusion device 65 and the first light-combining element 67 is also the same as in the first embodiment.

[0139] The axis along the principal ray of light emitted from the diffuser plate 70 is defined as the optical axis AX3. The optical axis AX3 coincides with the optical axes of the integrator optical element 21, the polarization conversion element 22, the overlapping lens 23, etc. In the first embodiment, the optical axis AX1 of the first light source unit 11 is orthogonal to the optical axis AX2 of the second light source unit 12. In contrast, in this embodiment, the optical axes AX1 of the first light source unit 11 and AX2 of the second light source unit 12 are arranged parallel to the X-axis and are parallel to each other, and are orthogonal to the optical axis AX3, which is parallel to the Y-axis.

[0140] The second light-combining element 68 is disposed on the optical axis AX3 between the first light-combining element 67 and the filter 15. Furthermore, the second light-combining element 68 is disposed at the intersection of the optical axes AX2 and AX3 of the second light source unit 12. The second light-combining element 68 has a substrate 72, a fifth optical film 73 disposed on one surface of the substrate 72, and an anti-reflective film 74 disposed on the other surface of the substrate 72. The fifth optical film 73 is composed of a dielectric multilayer film. The second light-combining element 68 is configured such that the surface of the substrate 72 faces at an angle of 45 degrees relative to both the optical axes AX2 and AX3. Furthermore, a red light diffuser 76 for diffusing red light LR is disposed on the optical axis AX2 between the second light source unit 12 and the second light-combining element 68.

[0141] Figure 16 This is a graph showing the spectral characteristics of the fifth optical film 73 of the second photosynthesizing element 68. Figure 16 In the figure, the horizontal axis represents wavelength (nm) and the vertical axis represents transmittance (%).

[0142] like Figure 16 As shown, the second optical combining element 68 reflects the red light LRs of the S-polarized component through the action of the fifth optical film 73, allowing the red light LRp of the P-polarized component to pass through, and allowing the blue light LBp and the green light LG to pass through.

[0143] In the first embodiment, the diffuser 44 functions as a reflective diffuser for blue light LBc1 and as a transmissive diffuser for red light LR, thus requiring a dichroic film that reflects blue light LBc1 and transmits red light LR. In contrast, the diffuser 70 of this embodiment only needs to function as a reflective diffuser for both blue light LBc1 and red light LRc1, therefore the dichroic film is not required, and a reflective film (not shown) is provided instead.

[0144] The following explains the operation of each color of light.

[0145] The operation of the blue light LBs emitted from the first light source unit 11 and the green light LG emitted from the wavelength conversion element 13 is the same as that of the light source device 100 in the first embodiment, so the description is omitted.

[0146] In the second light source unit 12, the S-polarized red light LRs emitted from the second light-emitting element 32 is diffused by the red light diffuser 76, reflected by the second light combining element 68, and transmitted through the first light combining element 67. The S-polarized red light LRs emitted from the first light combining element 67, like the S-polarized blue light LBs emitted from the first light source unit 11, is converted into a predetermined circularly polarized, for example, right-hand circularly polarized red light LRc1 by passing through the second phase difference plate 20. In this embodiment, the second phase difference plate 20 imparts a phase difference to both the blue light LBs and the red light LRs. The right-hand circularly polarized red light LRc1 is incident on the diffuser 70 in a state where it is focused by the focusing / pickup element 19. The right-hand circularly polarized red light LRc1 is diffused by the diffuser 70 and converted into left-hand circularly polarized red light LRc2. The left-hand circularly polarized red light LRc2 is parallelized by the focusing / pickup element 19 and then passes through the second phase difference plate 20, thereby being converted into P-polarized red light LRp. The P-polarized red light LRp passes through the first optical combining element 67 and the second optical combining element 68, and travels toward the filter 15.

[0147] As described above, blue light LBp, green light LG, and red light LRp are synthesized by a light-combining element 64, which consists of a first light-combining element 67 and a second light-combining element 68. White synthesized light LW is emitted from the light-combining element 64. The function of the filter 15 is the same as in the first embodiment.

[0148] [Effects of the fourth implementation method]

[0149] In the light source device 140 of this embodiment, the characteristics of the composite light LW emitted from the light source device 140 can also be changed by moving the filter 15 between the first position and the second position. When applied to the projector 10, the same effect as in the first embodiment can be obtained, such as the ability to switch between color reproduction emphasis mode and brightness emphasis mode.

[0150] In this embodiment, the filter 15 is disposed on the optical axis AX3 between the second optical combining element 68 and the integrator optical element 21, but it can also be disposed on the optical axis AX3 between the first optical combining element 67 and the second optical combining element 68 instead.

[0151] [Fifth Implementation]

[0152] The following uses Figure 17 as well as Figure 18 The fifth embodiment of the present invention will be described.

[0153] The basic structure of the projector in the fifth embodiment is the same as that in the first embodiment, but the structure of the light source device is different from that in the first embodiment. Therefore, the description of the basic structure of the projector is omitted.

[0154] Figure 17 This is a schematic structural diagram of the light source device 150 according to the fifth embodiment.

[0155] exist Figure 17 In the first embodiment, for use with Figure 2 The same constituent elements are labeled with the same reference numerals, and the descriptions are omitted.

[0156] like Figure 17 As shown, the light source device 150 of this embodiment includes a first light source unit 11, a second light source unit 12, a wavelength conversion element 13, a light combining element 14, a filter 85, a parallelization element 16, a diffusion device 17, a focusing element 18, a focusing / pickup element 19, a second phase difference plate 20, an integrator optical element 21, a polarization conversion element 22, an overlapping lens 23, and a control unit 24.

[0157] The position and structure of the filter 85 in the light source device 150 of this embodiment differ from those in the light source device 100 of the first embodiment. Specifically, in this embodiment, the filter 85 is disposed on the optical axis AX2 between the integrator optical element 21 and the polarization conversion element 22. In other words, the integrator optical element 21 is disposed on the light incident side of the filter 85. The polarization conversion element 22 is disposed on the light emitting side of the filter 85. Furthermore, the filter 85 is preferably disposed close to the polarization conversion element 22.

[0158] The integrator optical element 21 in this embodiment corresponds to the first optical element of the technical solution. The polarization conversion element 22 in this embodiment corresponds to the second optical element of the technical solution.

[0159] Figure 18 This is an enlarged view showing the vicinity of filter 85 and polarization conversion element 22. Figure 18 In the accompanying drawings, the filter 85 in the first position is shown in solid line, and the filter 85 in the second position is shown in dashed line. Furthermore, for ease of observation, the positions of the filter 85 in the first position and the filter 85 in the second position are shown offset in the direction of light travel.

[0160] As described in the first embodiment, the first multi-lens array 48 of the integrator optics 21 splits the synthesized light LW emitted from the light synthesizing element 14 into multiple beams, which are then incident on the second multi-lens array 49. Therefore, as... Figure 18 As shown, multiple beams constituting the composite light LW are emitted from the second multi-lens array 49. Here, any two adjacent beams among the multiple beams are designated as the first beam L1 and the second beam L2.

[0161] On the other hand, the polarization conversion element 22 has a structure in which multiple polarization separation films 87 and multiple reflective films 88 are alternately arranged, requiring multiple light beams to be incident on each of the multiple polarization separation films 87. Therefore, the polarization conversion element 22 has multiple light incident regions corresponding to the multiple polarization separation films 87. Figure 18 In the polarization conversion element 22 shown, the light incident region of the first beam L1 is set as the first light incident region 22A, and the light incident region of the second beam L2 is set as the second light incident region 22B.

[0162] The filter 85 includes a substrate 90, a first optical film 91 disposed on one side of the substrate 90, and a second optical film 92 disposed on the other side of the substrate 90. The first optical film 91 and the second optical film 92 are each composed of a dielectric multilayer film. In the first to fourth embodiments, the first and second optical films are disposed on the entire surface of the substrate. In contrast, in this embodiment, the first optical film 91 and the second optical film 92 are respectively divided and disposed in a manner corresponding to multiple light incident regions of the polarization conversion element 22. Therefore, in the following description, a region in the filter 85 in which the divided first optical film 91 and the second optical film 92 are disposed is referred to as a filter section. The filter section in which the first light beam L1 is incident is designated as the first filter section 85A, and the filter section in which the second light beam L2 is incident is designated as the second filter section 85B. The spectral characteristics of the first optical film 91 and the second optical film 92 are the same as those of the first optical film 41 and the second optical film 42 in the first embodiment.

[0163] In this embodiment, such as Figure 18 As shown by the solid line, at the first position of filter 85, the first filter section 85A is positioned opposite the first light incident region 22A of polarization conversion element 22, and the second filter section 85B is positioned opposite the second light incident region 22B of polarization conversion element 22. At this time, the composite light LW containing green light LG passes through filter 85. Furthermore, as... Figure 18 As shown by the dashed line, at the second position of the filter 85, the first filter section 85A is positioned opposite the region between the first light incident region 22A and the second light incident region 22B of the polarization conversion element 22. At this time, the composite light LW containing green light LG does not pass through the filter 85, but passes through the substrate 90 between the two adjacent filter sections.

[0164] [Effects of the 5th Embodiment]

[0165] In the light source device 150 of this embodiment, the characteristics of the composite light LW emitted from the light source device 150 can also be changed by moving the filter 85 between the first position and the second position. When applied to the projector 10, the same effect as in the first embodiment can be obtained, such as the ability to switch between color reproduction emphasis mode and brightness emphasis mode.

[0166] In the light source device 150 of this embodiment, when the filter 85 is moved between the first position and the second position, it is not necessary to move the entire filter 85 to the outside of the area through which multiple beams pass; only the width of one light incident area of ​​the polarization conversion element 22 needs to be moved. Thus, in this embodiment, the moving distance of the filter 85 can be smaller than that of the light source devices of the first to fourth embodiments, thereby enabling miniaturization of the light source device 150.

[0167] Furthermore, the scope of the present invention is not limited to the embodiments described above, and various modifications can be made without departing from the spirit of the invention. Additionally, one aspect of the present invention can be configured by appropriately combining the feature portions of the above embodiments.

[0168] For example, the light-combining element in the first embodiment has the characteristic of allowing blue and red light to pass through and reflecting green light, but it may also have the opposite characteristic, reflecting blue and red light while allowing green light to pass through. Furthermore, the light source device has a diffusion device that diffuses both blue and red light, but it may also replace this structure with a diffusion device that diffuses blue light and a diffusion device that diffuses red light separately. Additionally, the first light source unit may not necessarily have a first phase difference plate; for example, the first light source unit may contain a first light-emitting element that emits blue light with a P-polarization component and a first light-emitting element that emits blue light with an S-polarization component.

[0169] Furthermore, the specific descriptions regarding the shape, quantity, arrangement, materials, etc., of the various components of the light source device and projector are not limited to the above embodiments and can be appropriately modified. Additionally, the above embodiments show an example of mounting the light source device of the present invention on a projector using a liquid crystal panel, but this is not a limitation. The light source device of the present invention can also be applied to a projector using a digital micromirror device as a light modulation device. Furthermore, the projector may not have multiple light modulation devices, or it may be a single-panel projector with only one light modulation device.

[0170] The above embodiments illustrate an example of applying the light source device of the present invention to a projector, but are not limited thereto. The light source device of the present invention can also be applied to lighting fixtures, automotive headlights, etc.

[0171] [Summary of this disclosure]

[0172] The following is a summary published in this note.

[0173] (Postscript 1)

[0174] A light source device includes: a first light source unit that emits first light in a first wavelength band, the first light in the first wavelength band including a first polarization component and a second polarization component different from the first polarization component; a second light source unit that emits second light in a second wavelength band different from the first wavelength band; a wavelength conversion element that converts the first light into third light in a third wavelength band different from the first and second wavelength bands; a light combining element that combines the first light, the second light, and the third light to emit combined light; and a filter through which the third light is incident, the filter causing the first light to emit a second light in a third wavelength band different from the first and second wavelength bands. The light in a portion of the third band is reduced. The light combining element reflects the first polarization component of the first light emitted from the first light source and allows the second polarization component to pass through. This allows the wavelength conversion element to emit light in either direction of the first polarization component or the second polarization component. The light combining element allows any one of the first light, the second light, and the third light to pass through and reflects any other light. The filter is movable between a first position where the third light passes through the filter and a second position where the third light does not pass through the filter.

[0175] According to the structure in Appendix 1, by moving the filter between the first and second positions, the characteristics of the synthesized light emitted from the light source device can be changed.

[0176] (Postscript 2)

[0177] According to Appendix 1, the light source device further includes a diffusion device that diffuses the first light and the second light.

[0178] According to the structure in Appendix 2, the illuminance distribution of the first and second lights can be made more uniform, reducing color unevenness. Furthermore, when each light source unit has a laser light source, speckle noise in the image when the light source device is applied to a projector can be suppressed. Moreover, since it is not necessary to separately prepare diffusion devices for the first and second lights, the number of components in the light source device can be reduced and miniaturized.

[0179] (Note 3)

[0180] According to the light source device described in Appendix 2, the diffusion device is disposed between the light-combining element and the second light source unit. The diffusion device has a diffusion structure on the incident surface of the first light reflected by the light-combining element to diffuse the first light and the second light, and has a reflective film on the surface opposite to the incident surface of the light to reflect the first light and transmit the second light.

[0181] According to the structure in Appendix 3, even when a diffusion device is present, it is possible to suppress the enlargement of the light source device in the direction intersecting the optical axis between the light synthesis element and the second light source unit.

[0182] (Postscript 4)

[0183] The light source device according to any one of Appendix 1 to Appendix 3, wherein the light source device further comprises a parallelizing element disposed on the light incident side of the filter, the parallelizing element being substantially parallelized to the third light.

[0184] According to the structure in Appendix 4, since the light incident angle dependence can be disregarded when designing the filter, it is easy to improve the characteristics of the filter.

[0185] (Note 5)

[0186] According to any one of the appendices 1 to 4, the light incident surface of the filter intersects the principal ray of the third light at an angle other than 90 degrees.

[0187] According to the structure in Appendix 4, the amount of light returning to the wavelength conversion element and each light source after being reflected by the filter can be reduced. This improves the reliability of the wavelength conversion element and each light source.

[0188] (Note 6)

[0189] According to any one of Appendices 1 to 5, the first light source unit comprises: a first light-emitting element that emits the first light; and a first phase difference element disposed between the first light-emitting element and the light-combining element, which imparts a phase difference to the first light, wherein the first light emitted from the light-combining element is incident on the wavelength conversion element, and the first phase difference element is rotatable about an axis intersecting the light incident surface of the first phase difference element.

[0190] According to the structure in Appendix 6, by rotating the first phase difference element, the ratio of the first polarization component to the second polarization component can be changed, and the proportion of the first light incident on the wavelength conversion element can be changed.

[0191] (Note 7)

[0192] The light source device according to any one of Appendices 1 to 6, wherein the light source device further comprises a control unit that individually controls the current value supplied to the first light source unit when the filter is in the first position to be different from the current value supplied to the first light source unit when the filter is in the second position.

[0193] According to the structure in Appendix 7, the control unit can individually control the current value supplied to the first light source unit depending on whether the filter is in the first or second position.

[0194] (Postscript 8)

[0195] According to the light source device described in Appendix 7, wherein the first light is blue light, the second light is red light, and the third light is green light, the control unit performs the following control: when the filter is in the first position, the current value supplied to the first light source unit is greater than the current value supplied to the first light source unit when the filter is in the second position.

[0196] According to the structure in Appendix 8, the white balance of the synthesized light can be adjusted.

[0197] (Note 9)

[0198] According to the light source device described in Appendix 8, the control unit further performs the following control: when the filter is in the first position, the current value supplied to the second light source is less than the current value supplied to the second light source when the filter is in the second position.

[0199] According to the structure in Appendix 9, the brightness reduction when the filter is in position 1 can be minimized and the white balance of the synthesized light can be adjusted.

[0200] (Postscript 10)

[0201] According to any one of Appendices 1 to 9, the light source device wherein the light combining element combines the third light incident from the wavelength conversion element along the first direction and the second light incident from the second light source unit along the second direction intersecting the first direction, and the filter is disposed between the light combining element and the wavelength conversion element.

[0202] According to the structure in Appendix 10, since the second light is impermeable to the filter, the filter specifications become simpler compared to the case where the second light is permeable to the filter. This reduces the manufacturing cost of the filter and makes it easier to achieve the desired spectral characteristics.

[0203] (Postscript 11)

[0204] According to any one of Appendices 1 to 9, the light source device further comprises: a first optical element disposed on the light incident side of the filter, which splits the synthesized light emitted from the light synthesizing element into a first beam and a second beam; and a second optical element disposed on the light emitting side of the filter, having a first light incident region where the first beam is incident and a second light incident region where the second beam is incident, the filter having a first filter portion where the first beam is incident and a second filter portion where the second beam is incident, wherein at the first position of the filter, the first filter portion is disposed opposite to the first light incident region of the second optical element, and the second filter portion is disposed opposite to the second light incident region of the second optical element, and at the second position of the filter, the first filter portion is disposed opposite to the region between the first light incident region and the second light incident region of the second optical element.

[0205] According to the structure in Appendix 11, since the movement distance of the filter between the first and second positions can be reduced, the light source device can be miniaturized.

[0206] (Postscript 12)

[0207] According to any one of Appendices 1 to 11, the cross-sectional shape of the first light incident on the filter is an ellipse having a major axis and a minor axis, the cross-sectional shape of the third light incident on the filter is circular, the length of the diameter of the cross-sectional shape of the third light is approximately the same as either the length of the diameter of the cross-sectional shape of the first light along the major axis or the length of the diameter along the minor axis, and the filter is movable in a direction along the approximately coinciding axis, either along the major axis or along the minor axis.

[0208] According to the structure in Appendix 12, it is possible to suppress color unevenness during mode switching.

[0209] (Postscript 13)

[0210] A projector comprising: a light source device as described in any one of Appendices 1 to 12; a light modulation device for modulating light containing the composite light emitted from the light source device according to image information; and a projection optics device for projecting the light modulated by the light modulation device.

[0211] According to the structure in Appendix 13, a projector capable of switching between color reproduction emphasis mode and brightness emphasis mode can be realized.

Claims

1. A light source device comprising: The first light source emits first light of a first wavelength band, the first light of the first wavelength band containing a first polarization component and a second polarization component different from the first polarization component; The second light source emits a second light of a second wavelength, which is different from the first wavelength. A wavelength conversion element that converts the first light into a third light in a third band, which is different from the first band and the second band; A light combining element that combines the first light, the second light, and the third light to emit combined light; and A filter, to which the third light is incident, reduces the light intensity of a portion of the third wavelength band. The light combining element reflects the first polarization component of the first light emitted from the first light source and allows the second polarization component to pass through, thereby causing the wavelength conversion element to emit light in either the first polarization component or the second polarization component in either direction. The light-combining element allows the first and second light rays to pass through and reflects the third light ray, or reflects the first and second light rays and allows the third light ray to pass through. The filter is movable between a first position where the third light passes through the filter and a second position where the third light does not pass through the filter. The light combining element combines the third light incident from the wavelength conversion element along the first direction and the second light incident from the second light source along the second direction intersecting the first direction. The filter is disposed between the photosynthesizing element and the wavelength conversion element.

2. The light source device according to claim 1, wherein, The light source device also includes a diffusion device that diffuses the first light and the second light.

3. The light source device according to claim 2, wherein, The diffusion device is disposed between the photosynthesizing element and the second light source. The diffusion device has a diffusion structure on a first surface on which the first light reflected by the photosynthesizing element is incident, which diffuses the first light and the second light, and a reflective film on a second surface opposite to the first surface, which reflects the first light and allows the second light to pass through.

4. The light source device according to any one of claims 1 to 3, wherein, The light source device also includes a parallelizing element, which is disposed on the light incident side of the filter to make the third light approximately parallel.

5. The light source device according to any one of claims 1 to 3, wherein, The light incident surface of the filter intersects the principal ray of the third light at an angle of more than 90 degrees.

6. The light source device according to any one of claims 1 to 3, wherein, The first light source unit includes: A first light-emitting element, which emits the first light; and A first phase difference element is disposed between the first light-emitting element and the light-combining element to impart a phase difference to the first light. The first light emitted from the photosynthesizing element is incident on the wavelength conversion element. The first phase difference element is capable of rotating about an axis that intersects the light incident surface of the first phase difference element.

7. The light source device according to any one of claims 1 to 3, wherein, The light source device further includes a control unit, which controls the current value supplied to the first light source unit when the filter is in the first position to be different from the current value supplied to the first light source unit when the filter is in the second position.

8. The light source device according to claim 7, wherein, The first light is blue light. The second light is red light. The third light is green light. The control unit performs the following control: when the filter is in the first position, the current value supplied to the first light source is greater than the current value supplied to the first light source when the filter is in the second position.

9. The light source device according to claim 8, wherein, The control unit also performs the following control: when the filter is in the first position, the current value supplied to the second light source is less than the current value supplied to the second light source when the filter is in the second position.

10. The light source device according to any one of claims 1 to 3, wherein, The light source device also includes: A first optical element, disposed on the light incident side of the filter, splits the synthesized light emitted from the light combining element into a first beam and a second beam; and A second optical element is disposed on the light-emitting side of the filter, having a first light-incident region where the first light beam is incident and a second light-incident region where the second light beam is incident. The filter has a first filter section for the first light beam incident and a second filter section for the second light beam incident. At the first position of the filter, the first filter portion is positioned opposite the first light incident region of the second optical element, and the second filter portion is positioned opposite the second light incident region of the second optical element. At the second position of the filter, the first filter portion is positioned opposite the region between the first light incident region and the second light incident region of the second optical element.

11. The light source device according to any one of claims 1 to 3, wherein, The cross-sectional shape of the first light incident on the filter is an ellipse with a major axis and a minor axis. The cross-sectional shape of the third light incident on the filter is circular. The length of the diameter in the cross-sectional shape of the third beam is approximately the same as either the length of the diameter along the major axis or the length of the diameter along the minor axis in the cross-sectional shape of the first beam. The filter is movable in one of the directions along the long axis and the short axis, in a direction that is approximately the same as the axis.

12. A projector comprising: The light source device according to any one of claims 1 to 3; A light modulation apparatus that modulates light containing the synthesized light emitted from the light source apparatus according to image information; and A projection optical device that projects light modulated by the light modulation device.

Images