JP2019028442A - Light source device and projection type display device - Google Patents

Abstract

To provide a downsized and broad color area light source device with a broad color area that efficiently converges light from a blue solid light source and from a red solid light source.SOLUTION: A light source device 41 comprises: a blue semiconductor laser 16; a red semiconductor laser 20; a first phase difference plate 29 that produces a phase difference in light from the blue semiconductor laser; a dichroic mirror 30 that allows light from the blue semiconductor laser and the red semiconductor laser to be incident from the same direction, and polarizes and separates the light from the blue semiconductor laser; a fluorescent plate 36 that emits fluorescent light excited by the light from one blue semiconductor laser separated by the dichroic mirror; a quater wavelength plate 37 that converts polarization of light from other blue semiconductor separated by the dichroic mirror and the light from the red semiconductor laser into circular polarization; and a reflection plate 40 that reflects the light transmitting the quater wavelength plate.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to a projection display apparatus that irradiates an image formed on a small light valve with illumination light and enlarges and projects the image on a screen by a projection lens.

  Many light source devices using a solid-state light source of a semiconductor laser or a light emitting diode having a long life are disclosed as light sources of a projection display device using a mirror deflection type digital micromirror device (DMD) or a light valve of a liquid crystal panel. Yes. Among them, a wide color gamut and highly efficient light source device using a blue solid light source and a red solid light source is disclosed (see Patent Document 1).

JP 2012-234161 A

  The present disclosure provides a light source device and a projection display device that are compact and have a high color purity and a wide color gamut by using a configuration in which light from a blue solid light source and a red solid light source is collected and synthesized by the same optical system.

  The light source device of the present disclosure includes a blue solid light source, a red solid light source, a first phase difference plate, a dichroic mirror, a fluorescent plate, a second phase difference plate, and a reflection plate. The first retardation plate causes a phase difference in the light from the blue solid light source. In the dichroic mirror, light from the blue solid light source and the red solid light source is incident from the same direction, and the light from the blue solid light source is polarized and separated. The fluorescent plate is excited by light from one blue solid light source separated by the dichroic mirror and emits fluorescent light. The second retardation plate converts the light from the other blue solid light source and the light from the red solid light source separated by the dichroic mirror into circularly polarized light. The reflecting plate reflects the light transmitted through the second retardation plate.

  A projection display device according to the present disclosure includes the light source device according to the present disclosure, an illumination optical system that collects light from the light source device and illuminates an illuminated area, and an image forming element that forms an image according to a video signal. A projection lens for enlarging and projecting an image formed by the image forming element.

  According to the present disclosure, a light source device that is compact and has a high color purity and a wide color gamut can be configured by condensing and combining light from a blue solid light source and a red solid light source with the same optical system. Therefore, it is possible to realize a projection display device that is small in size and has a high color gamut and a long life.

Configuration diagram of light source device according to Embodiment 1 Configuration diagram of first retardation plate according to Embodiment 1 Diagram showing spectral characteristics of dichroic mirror Spectral characteristics of light emitted from the light source device Configuration diagram of a projection display apparatus according to Embodiment 2 Configuration diagram of a projection display apparatus according to Embodiment 3

  Hereinafter, embodiments for carrying out the present disclosure will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 is a configuration diagram of a light source device according to the first embodiment. The light source device 41 includes a blue solid-state light source unit 19 including a blue semiconductor laser 16 that is a blue solid light source, a collimating lens 17 and a heat radiating plate 18, a red semiconductor laser 20 that is a red solid light source, a collimating lens 21, and a heat radiating plate 22. And a red solid light source unit 23. In the blue solid light source unit 19 and the red solid light source unit 23, their heat radiation plates 18 and 22 are joined to a heat sink 24. In the traveling direction of the emitted light from the blue solid light source unit 19 and the red solid light source unit 23, the lens 26, the lens 27, the first diffusion plate 28, the first phase difference plate 29, and the dichroic mirror 30 are arranged in this order. Be placed.

  The condenser lenses 31 and 32 collect the light reflected by the dichroic mirror 30 and irradiate the phosphor layer 33 of the phosphor plate 36 in order to excite the phosphor, and collect the fluorescent light emitted by the excitation. The fluorescent plate 36 includes an aluminum substrate 34 on which a reflective film and a phosphor layer 33 are formed, and a motor 35. In the traveling direction of the light transmitted through the dichroic mirror 30, a quarter wave plate 37, a condenser lens 38, a second diffusion plate 39, and a reflection plate 40, which are phase difference plates, are arranged in this order. FIG. 1 shows the appearance of each light beam 25 emitted from the solid-state light source (the light traveling direction is indicated by a unidirectional arrow) and the polarization direction of the light incident on and emitted from the dichroic mirror 30. Yes.

  The blue solid light source unit 19 is configured by arranging two (2 × 4) blue semiconductor lasers 16 and a collimating lens 17 two-dimensionally on a heat radiating plate 18 at regular intervals. Solid light source units 19 are arranged on both sides of the red solid light source unit 23. The red solid light source unit 23 is configured by two-dimensionally arranging a red semiconductor laser 20 and a collimating lens 21 in a square arrangement of eight (2 × 4) on a heat radiating plate 22 at regular intervals. One set is arranged at the center portion between the light source units 19. The heat sink 24 is for cooling the blue semiconductor laser 16 and the red semiconductor laser 20.

  The blue semiconductor laser 16 emits blue color light with a wavelength width of 447 nm to 462 nm and emits linearly polarized light. Each blue semiconductor laser is arranged so that the polarized light emitted from the blue semiconductor laser 16 becomes S-polarized light with respect to the incident surface of the dichroic mirror 30. The red semiconductor laser 20 emits red color light with a wavelength width of 633 nm to 649 nm and emits linearly polarized light. The red semiconductor lasers are arranged so that the polarized light emitted from the red semiconductor laser 20 becomes P-polarized light with respect to the incident surface of the dichroic mirror 30.

  Light emitted from the plurality of blue semiconductor lasers 16 is condensed by the corresponding collimator lens 17 and converted into a parallel light beam 25. The luminous flux 25 group is further reduced in diameter by a convex lens 26 and a concave lens 27 and is incident on the first diffusion plate 28.

  The light emitted from the plurality of red semiconductor lasers 20 is condensed by the corresponding collimator lens 21 and converted into a parallel light beam 25. The luminous flux 25 group is further reduced in diameter by a convex lens 26 and a concave lens 27 and is incident on the first diffusion plate 28.

  The first diffusing plate 28 is formed by forming a diffusing surface with a fine lens shape formed on a glass substrate, and diffuses incident light. The diffusion angle, which is the half-value angle width that is 50% of the maximum intensity of the diffused light, is as small as about 4 degrees, and maintains the polarization characteristics. The light emitted from the first diffusion plate 28 enters the first retardation plate 29.

  FIG. 2 shows the configuration of the first retardation plate 29. FIG. 2 shows aspects of blue laser light and red laser light incident on the first retardation plate 29. 2A is a side view as viewed in the z-axis direction, and FIG. 2B is a plan view of FIG. 2A as viewed in the −y direction. The first retardation plate 29 is a microstructured retardation plate that forms a fine structure on the glass substrate 42 and generates a phase difference due to birefringence. The microstructural retardation film is described in, for example, International Publication No. 2017/061170. In the first retardation plate 29, a retardation layer forming region 43 and a retardation layer non-forming region 44 are formed on a glass substrate 42. A retardation layer forming region 43 is formed in a region where blue laser light is incident, and the retardation layer forming region 43 is a quarter wavelength plate. The quarter-wave plate is a retardation plate whose phase difference becomes a quarter wavelength near the emission center wavelength of the blue semiconductor laser 16.

  It arrange | positions so that the optical axis angle (theta) of the phase difference layer formation area | region shown to (c) of FIG. 2 may be set to about 63.5 degree | times. By setting the optical axis angle θ to 63.5 degrees, the incident S-polarized (90-degree direction) blue light can be controlled to a ratio of about 20% for the P-polarized component and about 80% for the S-polarized component. Further, the first retardation plate 29 can be provided with a rotation mechanism of about ± 5 degrees to adjust the ratio of the P-polarized component and the S-polarized component of the light. Since the microstructure of the first retardation plate 29 is made of an inorganic material by a nanoprint method, the retardation layer forming region and the retardation layer non-forming region 44 can be relatively easily manufactured on the substrate. Since it is an inorganic material, it is excellent in durability and reliability like optical crystals such as quartz. On the other hand, P-polarized light from the red solid-state light source unit 23 is incident on the phase difference layer non-formation region 44 of the first retardation plate 29, and therefore is transmitted as it is without being separated by polarization.

  As the first retardation plate 29 described above, a retardation layer forming region is formed on a part of a glass substrate, but a plurality of retardation plates having a retardation layer forming region formed on the entire surface of the glass substrate are used. Thus, it may be disposed at a position where the blue laser light is incident.

  The P-polarized light, S-polarized blue laser light, and P-polarized red laser light emitted from the first retardation plate 29 are incident on the dichroic mirror 30. Thus, the light from the blue solid light source unit 19 and the red solid light source unit 23 enters the dichroic mirror 30 from the same direction.

  FIG. 3 shows the spectral characteristics of the dichroic mirror 30. The spectral characteristics indicate the transmittance with respect to the wavelength. The dichroic mirror 30 has a spectral characteristic that transmits P-polarized light and reflects S-polarized light with high reflectance with respect to blue laser light with a wavelength of 447 to 462 nm and red laser light with a wavelength of 633 to 649 nm. Furthermore, it is the characteristic which permeate | transmits the P polarized light and S polarized light of the color light containing green and red of 475-615 nm with high transmittance | permeability of 96% or more, respectively. About 80% of the S-polarized blue laser light reflected by the dichroic mirror 30 is condensed by the condenser lenses 31 and 32, and the diameter at which the light intensity is 13.5% of the peak intensity is defined as the spot diameter. The light is superimposed on the spot light having a diameter of 1.5 mm to 2.5 mm and is incident on the fluorescent plate 36. The first diffusion plate 28 diffuses the light so that the spot light has a desired diameter.

The fluorescent plate 36 is an aluminum substrate 34 on which a reflection film and a phosphor layer 33 are formed, and a circular substrate that can be rotated and provided with a motor 35 at the center. The reflection film of the fluorescent plate 36 is a metal film or a dielectric film that reflects visible light, and is formed on the aluminum substrate 34. Further, a phosphor layer 33 is formed on the reflective film. In the phosphor layer 33, a Ce-activated YAG yellow phosphor that is excited by blue laser light and emits yellow light containing green and red components is formed. A typical chemical structure of the crystal matrix of this phosphor is Y ₃ Al ₅ O ₁₂ . The phosphor layer 33 is formed in an annular shape. The phosphor layer 33 excited by the spot light emits yellow light containing green and red components. The fluorescent plate 36 uses an aluminum substrate and is rotated, so that the temperature rise of the phosphor layer 33 due to excitation light can be suppressed, and the fluorescence conversion efficiency can be stably maintained.

  The light incident on the phosphor layer 33 fluoresces the green and red component color lights and exits the fluorescent plate 36. Further, the light emitted to the reflective film side is reflected by the reflective film and exits the fluorescent plate 36. The green and red color lights emitted from the fluorescent plate 36 become natural light, and are condensed again by the condenser lenses 31 and 32, converted into substantially parallel light, and then transmitted through the dichroic mirror 30.

  On the other hand, the P-polarized blue laser light and red laser light transmitted through the dichroic mirror 30 are incident on a quarter-wave plate 37 that is a second retardation plate. The quarter-wave plate 37 is a broadband retardation plate that produces a quarter-wave phase difference in the wavelength band of blue laser light and red laser light. The quarter wavelength plate 37 is disposed at an optical axis angle of 45 degrees when the P polarization direction in FIG. 1 is 0 degree. Blue laser light and red laser light are converted from P-polarized light to circularly-polarized light by the quarter-wave plate 37. The quarter-wave plate 37 is a thin film phase difference plate using birefringence by oblique deposition of a dielectric material. About a thin film phase difference plate, it describes in Unexamined-Japanese-Patent No. 2012-242449, for example. Since such a thin film retardation plate is formed of an oblique vapor deposition film, a thick film can be formed relatively easily, so that a broadband quarter-wave plate can be configured. Further, the thin film retardation plate is made of an inorganic material, and is excellent in durability and reliability like an inorganic optical crystal such as quartz.

  The circularly polarized light that is transmitted through the quarter-wave plate 37 and enters the condenser lens 38 forms a condensing spot in the vicinity of the reflecting plate 40. The light condensed by the condenser lens 38 enters the second diffusion plate 39. The second diffuser plate 39 diffuses incident light to make the light intensity distribution uniform, and eliminates speckles in the laser light. The second diffusion plate 39 has a diffusing surface formed in a fine lens shape formed on a glass substrate. The diffusion angle of the second diffusing plate 39 is as small as about 4 degrees and maintains the polarization characteristics. The light from the second diffusion plate 39 is reflected by the reflection plate 40 on which a reflection film such as aluminum or a dielectric multilayer film is formed, the phase is inverted, and reversely circularly polarized light is obtained. The light is transmitted, condensed by the condenser lens 38, converted into parallel light, then transmitted through the quarter-wave plate 37 and converted into S-polarized light. The blue laser light and red laser light converted to S-polarized light by the quarter wavelength plate 37 are reflected by the dichroic mirror 30.

  In this way, the fluorescent light from the fluorescent plate 36, the blue laser light and the red laser light that have been efficiently polarized and converted are combined by the dichroic mirror 30 to emit white light.

  FIG. 4 shows spectral characteristics of light emitted from the light source device 41. As shown by the broken lines in FIG. 4, the primary color light of high color purity blue, green, and red can be obtained by color-separating the regions.

  Fluorescent light containing green and red components, blue laser light, and red laser light can provide light emission characteristics with high color purity of the three primary colors of blue, green, and red, wide color gamut, and good white balance. it can. Even if this emission spectrum characteristic is separated into three primary colors of blue, green and red by the optical system of the projection display device, it is possible to obtain monochromatic light with high color purity.

  As the first retardation plate, a microstructural retardation plate has been described, but a thin film retardation plate or quartz may be used. In addition, although the first retardation plate has been described using a quarter wavelength plate, in the case where the blue laser beam emits P-polarized light, the P-polarized component is approximately 20% from the P-polarized light, and the S-polarized light. The component needs to be separated into about 80%, and in that case, a half-wave plate can be used.

  Although the thin film phase difference plate has been described as the second phase difference plate, a fine structure phase difference plate or crystal may be used.

  Although the case where two blue solid light source units 19 and one red solid light source unit 23 are used for the light source device 41 has been described, if the blue laser light and the red laser light are separated on the first retardation plate, Each may be configured using a larger number of solid light source units.

  As described above, the light source device of the present disclosure includes a retardation plate that generates a phase difference in light from a blue solid light source, and condenses and combines the light from the blue solid light source and the red solid light source with the same optical system. Therefore, it is small, and the color purity of the three primary colors of blue, green, and red is high, and white light with a wide color gamut can be obtained.

(Embodiment 2)
FIG. 5 is a configuration diagram of the first projection display device 51 according to the second embodiment. As an image forming means, a TN (Twisted Nematic) mode or a VA (Vertical Alignment) mode, which uses an active matrix type transmissive liquid crystal panel in which a thin film transistor is formed in a pixel region, is used.

  The light source device 41 includes a blue semiconductor laser 16, a red semiconductor laser 20, a blue solid light source unit 19, a red solid light source unit 23, a heat sink 24, lenses 26 and 27, a first diffusion plate 28, a first retardation plate 29, and a dichroic. The mirror 30, condenser lenses 31 and 32, a fluorescent plate 36, a quarter-wave plate 37 that is a second phase difference plate, a condenser lens 38, a second diffusing plate 39, and a reflecting plate 40. The above is the same as the light source device 41 of the first embodiment.

  Light emitted from the light source device 41 includes a first lens array plate 200, a second lens array plate 201, a polarization conversion element 202, a superimposing lens 203, a blue reflecting dichroic mirror 204, a green reflecting dichroic mirror 205, and a reflection. Mirrors 206, 207, 208, relay lenses 209, 210, field lenses 211, 212, 213, incident side polarizing plates 214, 215, 216, liquid crystal panels 217, 218, 219, output side polarizing plates 220, 221, 222, red The light enters the projection lens 224 through an optical system including a color synthesis prism 223 composed of a reflective dichroic mirror and a blue reflective dichroic mirror.

  White light from the light source device 41 is incident on the first lens array plate 200 composed of a plurality of lens elements. The light beam incident on the first lens array plate 200 is divided into a number of light beams. A large number of the divided light beams converge on the second lens array plate 201 composed of a plurality of lenses. The lens elements of the first lens array plate 200 have an opening shape similar to the liquid crystal panels 217, 218, and 219. The focal length of the lens elements of the second lens array plate 201 is determined so that the first lens array plate 200 and the liquid crystal panels 217, 218, and 219 have a substantially conjugate relationship. The light emitted from the second lens array plate 201 enters the polarization conversion element 202.

  The polarization conversion element 202 includes a polarization separation prism and a half-wave plate, and converts natural light from the light source into light of one polarization direction. Since the fluorescent light is natural light, it is polarized and converted in one polarization direction, but the blue light is incident as P-polarized light and is therefore converted to S-polarized light. The light from the polarization conversion element 202 enters the superimposing lens 203. The superimposing lens 203 is a lens for superimposing and illuminating the light emitted from each lens element of the second lens array plate 201 on the liquid crystal panels 217, 218, and 219. The first lens array plate 200 and the second lens array plate 201, the polarization conversion element 202, and the superimposing lens 203 are used as an illumination optical system.

  The light from the superimposing lens 203 is separated into blue, green and red color light by a blue reflecting dichroic mirror 204 and a green reflecting dichroic mirror 205 which are color separation means. The green color light passes through the field lens 211 and the incident side polarizing plate 214 and enters the liquid crystal panel 217. The blue color light is reflected by the reflection mirror 206, then passes through the field lens 212 and the incident side polarizing plate 215 and enters the liquid crystal panel 218. The red color light is transmitted and refracted and reflected by the relay lenses 209 and 210 and the reflection mirrors 207 and 208, passes through the field lens 213 and the incident side polarizing plate 216, and enters the liquid crystal panel 219.

  The three liquid crystal panels 217, 218, and 219 change the polarization state of incident light by controlling the voltage applied to the pixels according to the video signal, and the transmission axes are orthogonal to both sides of each liquid crystal panel 217, 218, and 219. The light is modulated by combining the incident-side polarizing plates 214, 215, and 216 and the outgoing-side polarizing plates 220, 221, and 222 arranged so as to form green, blue, and red images. Each color light transmitted through the output side polarizing plates 220, 221, 222 is reflected by the color combining prism 223, and the red and blue color lights are reflected by the red reflecting dichroic mirror and the blue reflecting dichroic mirror, respectively, and combined with the green color light, The light enters the projection lens 224. The light incident on the projection lens 224 is enlarged and projected on a screen (not shown).

  The light source device is configured in a small size using a blue solid light source and a red solid light source, emits white light with high color purity and good white balance, and thus can realize a projection display device having a small size and a wide color gamut. . In addition, since the image forming means uses three liquid crystal panels that use polarized light instead of the time-division method, there is no color breaking, color reproduction is good, and a bright and high-definition projected image can be obtained. In addition, the total reflection prism is not required and the color combining prism is a small 45-degree incident prism compared to the case where three DMD elements are used, and thus the projection display apparatus can be made compact.

  As described above, the first projection display device 51 of the present disclosure includes the blue solid light source, the red solid light source, and the first retardation plate that controls the light from the blue solid light source to the polarization component having a certain ratio. A light source device that includes a dichroic mirror that separates polarized light, and that collects and synthesizes light of a blue solid light source and a red solid light source in the same optical system. For this reason, a small and wide color gamut projection display device can be configured.

  Although a transmissive liquid crystal panel is used as the image forming means, a reflective liquid crystal panel may be used. By using a reflective liquid crystal panel, a more compact and high-definition projection display device can be configured.

(Embodiment 3)
FIG. 6 is a configuration diagram of the second projection display device 52 according to the third embodiment. Three DMDs (Digital Micromirror Devices) are used as image forming means.

  The light source device 41 includes a blue semiconductor laser 16, a red semiconductor laser 20, a blue solid light source unit 19, a red solid light source unit 23, a heat sink 24, lenses 26 and 27, a first diffusion plate 28, a first retardation plate 29, and a dichroic. The mirror 30, condenser lenses 31 and 32, a fluorescent plate 36, a quarter-wave plate as a second retardation plate, a condenser lens 38, a second diffusing plate 39, and a reflecting plate 40. The above is the light source device 41 of the first embodiment.

  White light emitted from the light source device 41 enters the condenser lens 100 and is condensed on the rod 101. Light incident on the rod 101 is reflected a plurality of times inside the rod, so that the light intensity distribution is uniformed and emitted. Light emitted from the rod 101 is collected by the relay lens 102, reflected by the reflection mirror 103, then transmitted through the field lens 104, and enters the total reflection prism 105. The total reflection prism 105 is composed of two prisms, and a thin air layer 106 is formed on the adjacent surfaces of the prisms. The air layer 106 totally reflects light incident at an angle greater than the critical angle. The light from the field lens 104 is reflected by the total reflection surface of the total reflection prism 105 and enters the color prism 107.

  The color prism 107 is composed of three prisms, and a blue reflecting dichroic mirror 108 and a red reflecting dichroic mirror 109 are formed on the adjacent surfaces of the prisms. The light is separated into blue, red, and green color lights by the blue reflecting dichroic mirror 108 and the red reflecting dichroic mirror 109 of the color prism 107, and is incident on DMDs 110, 111, and 112, respectively. The DMDs 110, 111, and 112 deflect the micromirror according to the video signal and reflect the light into the light incident on the projection lens 113 and the light traveling outside the effective range of the projection lens 113. The light reflected by the DMDs 110, 111, and 112 passes through the color prism 107 again. In the process of passing through the color prism 107, the separated blue, red, and green color lights are combined and enter the total reflection prism 105.

  Since the light incident on the total reflection prism 105 is incident on the air layer 106 at a critical angle or less, it is transmitted and incident on the projection lens 113. In this manner, the image light formed by the DMDs 110, 111, and 112 is enlarged and projected on a screen (not shown).

  The light source device is configured in a small size using a blue solid light source and a red solid light source, emits white light with high color purity and good white balance, and thus can realize a projection display device having a small size and a wide color gamut. . In addition, since DMD is used for the image forming means, a projection display device having higher light resistance and heat resistance than the image forming means using liquid crystal can be configured. Furthermore, since three DMDs are used, color reproduction is good and a bright and high-definition projected image can be obtained.

  As described above, the second projection display device 52 of the present disclosure includes the blue solid light source, the red solid light source, and the first retardation plate that controls the light from the blue solid light source to a polarization component having a certain ratio. A light source device that includes a dichroic mirror that separates polarized light, and that collects and synthesizes light of a blue solid light source and a red solid light source in the same optical system. For this reason, a small and wide color gamut projection display device can be configured.

  The present disclosure relates to a projection display apparatus using an image forming unit such as a liquid crystal panel or DMD.

16 Blue semiconductor laser 17, 21 Collimating lens 18, 22 Radiator 19 Blue solid light source unit 20 Red semiconductor laser 23 Red solid light source unit 24 Heat sink 25 Light flux 26, 27 Lens 28 First diffuser plate 29 First retardation plate 30 Dichroic Mirror 31, 32, 38 Condenser lens 33 Phosphor layer 34 Aluminum substrate 35 Motor 36 Fluorescent plate 37 1/4 wavelength plate 39 Second diffuser plate 40 Reflector plate 41 Light source device 42 Glass substrate 43 Phase difference layer formation region 44 Phase difference layer non-phase difference layer Formation area 51, 52 Projection display device 100 Condensing lens 101 Rod 102, 209, 210 Relay lens 103, 206, 207, 208 Reflection mirror 104, 211, 212, 213 Field lens 105 Total reflection prism 106 Sky Layer 107 color prism 108,204 dichroic mirror 109 red reflection blue reflecting dichroic mirror 110, 111, 112 DMD
113, 224 Projection lens 200 First lens array plate 201 Second lens array plate 202 Polarization conversion element 203 Superposition lens 205 Green reflecting dichroic mirror 214, 215, 216 Incident side polarizing plates 217, 218, 219 Liquid crystal panel 220 , 221, 222 Output side polarizing plate 223 Color composition prism

Claims (15)

A blue solid light source;
A red solid light source;
A first retardation plate for causing a phase difference in light from the blue solid light source;
A dichroic mirror that receives light from the blue solid light source and the red solid light source from the same direction, and polarizes and separates the light from the blue solid light source;
A fluorescent plate that is excited by light from one of the blue solid light sources separated by the dichroic mirror and emits fluorescent light;
A second retardation plate for converting the polarization of the light from the other blue solid light source and the light from the red solid light source separated by the dichroic mirror into circularly polarized light;
A reflecting plate that reflects light transmitted through the second retardation plate;
A light source device.   The light source device according to claim 1, wherein the dichroic mirror combines light from the fluorescent plate and light from the reflective plate.   The light source device according to claim 1, wherein the first retardation plate is a quarter-wave plate or a half-wave plate.   The light source device according to claim 1, wherein the first retardation plate includes a region where a retardation layer is formed on a glass substrate and a region where the retardation layer is not formed.   The light source device according to claim 1, wherein the first retardation plate includes a rotation adjustment mechanism.   2. The light source device according to claim 1, wherein the second retardation plate is a ¼ wavelength plate that generates a ¼ wavelength phase difference in a wavelength band of light from the blue solid light source and the red solid light source. .   The light source device according to claim 1, wherein the first and second retardation plates are microstructured retardation plates using birefringence due to a microstructure.   The light source device according to claim 1, wherein the first and second retardation plates are thin film retardation plates using birefringence by oblique deposition.   The light source device according to claim 1, wherein the blue solid light source is a blue semiconductor laser.   The light source device according to claim 1, wherein the red solid light source is a red semiconductor laser.   The light source device according to claim 1, wherein light emitted from the blue solid light source and the red solid light source is linearly polarized light.   The light source device according to claim 1, wherein the fluorescent plate is a circular substrate that can be controlled to rotate, and includes a phosphor layer in which a yellow phosphor containing Ce-activated YAG green and red components is formed. A light source device according to claim 1;
An illumination optical system for condensing the light from the light source device and illuminating the illuminated area;
An image forming element that forms an image according to a video signal;
A projection display device, comprising: a projection lens that magnifies and projects an image formed by the image forming element.   The projection display device according to claim 13, wherein the image forming element is a liquid crystal panel.   The projection display device according to claim 13, wherein the image forming element is a mirror deflection type digital micromirror device (DMD).

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