JP2022017670A - Light source device and projection-type display device - Google Patents

Abstract

To provide a wide color gamut and small size light source device using solid light sources of red, green, and blue capable of eliminating speckle noises from the light source devices.SOLUTION: The light source device includes: laser light sources 22, 26, 30 of blue, green, and red for synthesizing a laser light from these laser light sources; dichroic mirrors 32, 33, 34 that synthesize laser light from these laser light sources; and a diffuse fluorescent board 41 that has an optical thin film layer 38 formed over the glass substrate 37, which transmits the light of the wavelength band of the laser light of blue, green, and red and reflects light from other visible light wavelength bands, and a diffuse fluorescent layer 39 that excites with blue laser light and diffuses blue, green, and red laser light.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to a projection type display device that irradiates an image formed on an image forming element with illumination light and magnifies and projects it on a screen by a projection lens.

As a light source for a projection type display device that uses a mirror-deflected digital micromirror device (DMD) or an image forming element of a liquid crystal panel, there are many light source devices that use a long-life semiconductor laser or a solid-state light source of a light emitting diode. It has been disclosed. Among them, a wide color gamut and highly efficient light source device using blue, green, and red laser light sources is disclosed. A light source device using a conventional solid-state light source is in front of a blue, green, and red laser light source, a small dichroic mirror that synthesizes condensed light from the laser light source, and a transmissive rotary diffuser and a rotary diffuser. The arranged diffuser plate constitutes a compact light source device while eliminating speckle noise and minute unevenness in brightness (see Patent Document).

Japanese Unexamined Patent Publication No. 2019-40177

In the configuration of the conventional light source device, a plurality of rotatable diffusers are not sufficient to eliminate speckle noise. Further, the light source device using the laser light has a problem that a minute brightness unevenness due to a minute emission size and the number of emissions of the laser light source is generated on the screen. Further, the green and red laser light sources have lower light output and luminous efficiency than the blue laser light source. Therefore, a large number of laser light sources are required to increase the brightness of the light source device, and there is a problem that the light source device becomes large in size.

Therefore, a compact light source device with a wide color gamut and a projection type display device using the light source device are configured while eliminating speckle noise and minute luminance unevenness by using solid blue, green, and red light sources. Was the issue.

The light source device of the present disclosure includes a blue, green, and red laser light sources, a dichroic mirror that synthesizes laser light from blue, green, and red laser light sources, and blue, green, and red laser light wavelengths on a glass substrate. Formed an optical thin film layer that transmits light in the band and reflects light in the other visible light wavelength band, and a diffuse fluorescent layer that excites light with blue laser light and diffuses blue, green, and red laser light. It is equipped with a diffused fluorescent plate.

According to the present disclosure, diffused blue, green, and red laser light sources and fluorescent light without speckle noise are efficiently combined on the same optical axis by a dynamic diffused fluorescent plate. Therefore, it is possible to configure a small light source device capable of adjusting the color gamut in a wide color gamut while eliminating speckle noise and minute luminance unevenness.

Configuration diagram of the light source device according to the first embodiment of the present disclosure. Cross-sectional configuration diagram of the diffusion fluorescent plate in the first embodiment The figure which shows the spectral characteristic of an optical thin film layer The figure which shows the transmittance characteristic with respect to the incident angle of an optical thin film layer The figure which shows the fluorescence spectrum characteristic Configuration diagram of the projection type display device according to the second embodiment of the present disclosure. Configuration diagram of the projection type display device according to the third embodiment of the present disclosure.

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 42 according to the first embodiment of the present disclosure.

The light source device 42 includes a blue laser light source 22, a green laser light source 26, and a red laser light source 30.

The blue laser light source 22 includes a blue semiconductor laser substrate 20 in which a plurality of blue semiconductor laser elements are arranged and a collimating lens array 21. The green laser light source 26 includes a green semiconductor laser substrate 24 in which a plurality of green semiconductor laser elements are arranged and a collimating lens array 25. The red laser light source 30 includes a red semiconductor laser substrate 28 in which a plurality of red semiconductor laser elements are arranged and a collimating lens array 29.

The light source device 42 further includes heat dissipation plates 23, 27, 31, blue reflection dichroic mirrors 32, 33, red reflection dichroic mirror 34, a condenser lens 35, a diffuser plate 36, a glass substrate 37, an optical thin film layer 38, and diffusion. A diffused fluorescent plate 41 composed of a fluorescent layer 39 and a motor 40 is provided. The figure shows the traveling direction of the light emitted from the laser light source.

The blue laser light source 22 is composed of a blue semiconductor laser substrate 20 and a collimating lens array 21 in which 16 (4 × 4) blue semiconductor laser elements are arranged two-dimensionally at regular intervals. The blue semiconductor laser substrate 20 emits blue colored light in a wavelength band of 465 ± 8 nm and emits linearly polarized light. The light emitted from the blue semiconductor laser substrate 20 is condensed by the corresponding collimating lens array 21 and converted into parallel light fluxes. The heat sink 23 is for cooling the blue semiconductor laser substrate 20.

The green laser light source 26 is composed of a green semiconductor laser substrate 24 and a collimating lens array 25 in which 24 (4 × 6) green semiconductor laser elements are arranged two-dimensionally at regular intervals. The green semiconductor laser substrate 24 emits green colored light in a wavelength band of 525 ± 8 nm and emits linearly polarized light. The light emitted from the green semiconductor laser substrate 24 is condensed by the corresponding collimating lens array 25 and converted into parallel light fluxes. The heat sink 27 cools the green semiconductor laser substrate 24.

The red laser light source 30 is composed of a red semiconductor laser substrate 28 and a collimating lens array 29 in which 24 (4 × 6) red semiconductor laser elements are arranged two-dimensionally at regular intervals. The red semiconductor laser substrate 28 emits red colored light in a wavelength band of 640 ± 8 nm and emits linearly polarized light. The light emitted from the red semiconductor laser substrate 28 is condensed by the corresponding collimating lens array 29 and converted into parallel light fluxes. The heat sink 31 is for cooling the red semiconductor laser substrate 28.

The laser light from the blue laser light source 22 is reflected by the blue-reflecting dichroic mirrors 32 and 33 and passes through the red-reflecting dichroic mirror 34.

The laser light from the green laser light source 26 passes through the blue-reflecting dichroic mirrors 32 and 33 and the red-reflecting dichroic mirror 34, respectively.

The laser light from the red laser light source 30 passes through the blue-reflecting dichroic mirror 32 and is reflected by the red-reflecting dichroic mirror 34.

The blue-reflecting dichroic mirrors 32 and 33 are arranged so that the incident angle is 45 degrees, and have the characteristic of transmitting red and green laser light at 95% or more and reflecting blue laser light at 97% or more. The half-value wavelength at which the transmittance is 50% is 490 nm for S polarization.

The red-reflecting dichroic mirror 34 has a characteristic that the incident angle is 45 degrees, the blue and green laser light is transmitted at 95% or more, and the red laser light is reflected at 97% or more. The half-value wavelength at which the transmittance is 50% is 585 nm for S polarization.

The blue, green, and red laser light synthesized by the blue-reflecting dichroic mirrors 32 and 33 and the red-reflecting dichroic mirror 34 enters the condenser lens 35, passes through the diffuser plate 36, and then collects light on the diffuser fluorescent plate 41. Will be done. The focused light is superimposed on the spot light having a spot diameter of 2 to 3 mm, where the diameter at which the light intensity is 13.5% with respect to the peak intensity is defined as the spot diameter. The diffuser plate 36 diffuses the light so that the diameter of the spot light becomes a desired diameter. The diffuser plate 36 forms a diffuser surface by forming fine microlenses formed on a glass substrate in an array, and diffuses incident light. The diffusion angle, which is a half-value angle width that is 50% of the maximum intensity of diffused light, is as small as about 3 degrees.

The diffuse fluorescent plate 41 is a rotation-controllable circular substrate provided with a glass substrate 37 having an optical thin film layer 38 and a diffuse fluorescent layer 39 formed therein, and a motor 40 in the center.

FIG. 2 shows a cross-sectional structure of a part of the diffusion fluorescent plate. The optical thin film layer 38 of the diffuse fluorescent plate 41 is a dielectric film having a characteristic of transmitting blue, green, and red laser light and reflecting other visible light, and is formed on the glass substrate 37. Further, a diffusion fluorescent layer 39 is formed on the optical thin film layer 38. In the diffuse fluorescent layer 39, the phosphor 51 is dispersed and filled in the silicone-based binder layer 50. The refractive index of the binder layer 50 is 1.46, and the refractive index of the phosphor is 1.83. The phosphor 51 is a Ce-activated YAG-based yellow phosphor that is excited by a blue laser beam and emits yellow light containing green and red components. The typical chemical structure of the crystal matrix of this fluorescent substance is Y3Al5O12. The optical thin film layer 38 and the diffuse fluorescent layer 39 are formed in an annular shape. By rotating the diffused fluorescent plate 41, it is possible to suppress the temperature rise of the diffused fluorescent layer due to the excitation light and stably maintain the fluorescence conversion efficiency.

The blue laser light incident on the diffuse fluorescent plate 41 passes through the optical thin film layer 38, excites the phosphor dispersed in the diffuse fluorescent layer 39, and emits fluorescence. Some blue laser light does not contribute to excitation and is diffused by the difference in refractive index between the binder layer 50 and the phosphor 51. A part of the diffused light is emitted from the diffused fluorescent layer 39, and a part is reflected by the optical thin film layer 38 on the incident light side, and then emitted from the diffused fluorescent layer 39. In addition, a part of the light is emitted to the incident light side of the diffused fluorescent plate. The thickness of the diffused fluorescent layer 39 and the filling rate of the phosphor are determined so that 50% of the light intensity of the incident blue laser light is excited and fluorescently converted, and 50% of the light intensity is the laser light that is not fluorescently converted. .. The directivity of the emitted fluorescence is almost perfect diffusion, and the aspect is shown in the figure.

On the other hand, the green and red laser light incident on the diffused fluorescent plate 41 passes through the optical thin film layer 38, is not excited by the diffuse fluorescent layer 39, and is diffused by the difference in refractive index between the binder layer 50 and the phosphor 51. .. A part of the light diffused by the diffused fluorescent layer 39 is emitted from the diffused fluorescent layer 39, and a part of the light is reflected by the optical thin film layer 38 on the incident light side and then emitted from the diffused fluorescent layer 39. The directivity of the emitted diffused light has a smaller spread than that of fluorescence, and the diffusion angle, which is the full width at half maximum, is about 20 degrees. This aspect is shown in the figure. The diffusion angle can be determined by the thickness of the diffusion fluorescent layer 39 and the filling rate of the phosphor 51.

By rotating the diffused fluorescent plate 41, the random interference pattern on the screen caused by the laser beam fluctuates at high speed in time and space, and speckle noise can be eliminated. In addition, it is possible to reduce minute brightness unevenness caused by the minute emission size and the number of emissions of the laser light source. In this way, the diffused fluorescent layer emits the excited yellow fluorescence and the diffused blue, green, and red laser light. Since the blue, green, and red laser lights are combined with fluorescent light without speckle noise, the light has a wide color gamut with speckle noise eliminated.

The amount of the phosphor 51 to be filled in the diffuse fluorescent layer 39 is significantly reduced, and as an alternative particle thereof, the refractive index is higher than that of the binder layer 50 and does not emit light by excitation with blue laser light, for example, the refractive index is 2.3. It may be used by filling it with a diffuser such as TiO2 particles. In this case, the fluorescence component is significantly reduced, and the laser light component having a large degree of diffusion is increased. Therefore, although the speckle noise increases, the color gamut near the emission wavelengths of the blue, green, and red laser light can be widened. The green and red color gamuts can be adjusted by the packing rate of the phosphor and the diffuser and their thickness. When only the diffuser is used without arranging the phosphor, the color gamut of the emission wavelengths of the blue, green, and red laser light can be widened.

FIG. 3 shows the spectral characteristics of the optical thin film layer. The spectral transmittance when the angle of incidence on the optical thin film layer 38 is 0 degrees is shown. The transmittance of blue, green, and red laser light in the wavelength band is 94% or more. The half-value wavelengths at which the transmittance is 50% are 440 nm, 485 nm, 505 nm, 545 nm, 620 nm, and 660 nm. Other than the wavelength bands of blue, green, and red laser light, the transmittance at 490 to 500 nm, 548 to 617 nm, and 664 to 700 nm is 10% or less. The characteristic of FIG. 2 is an example in which 55 layers of optical thin films are alternately formed on a glass substrate by alternately forming a high refractive index material such as TIO2 and a low refractive index material such as SiO2.

FIG. 4 shows the transmittance characteristics with respect to the incident angle of the optical thin film layer. It shows the average transmittance of P-polarized light and S-polarized light at 465 nm, 525 nm, and 640 nm. As the incident angle increases, the characteristics shown in FIG. 3 shift to the short wavelength side. When the incident angle is from 0 to 20 degrees, the transmittance of each laser beam at wavelengths of 465 nm, 525 nm, and 640 nm is 96% or more. When the incident angle is 30 degrees or more and up to 50 degrees, the transmittance of the green and red laser light at wavelengths of 525 nm and 640 nm is 10% or less, and the reflectance is 90% or more.

From FIGS. 3 and 4, the green and red laser light diffused by the diffused fluorescent layer and having an incident angle of 30 degrees or more on the optical thin film layer is reflected by the optical thin film with a reflectance of 90% or more, and then. Emit the diffuse fluorescent layer. In this way, the efficiency of the emitted green and red laser light can be increased by utilizing the incident angle dependence of the transmittance of the optical thin film layer.

FIG. 5 shows the characteristics of the fluorescence spectrum. The fluorescence emitted to the emitted light side of the diffused fluorescence layer is emitted with the spectral characteristics of FIG. On the other hand, the light excited and emitted toward the optical thin film layer side of the diffused fluorescence layer transmits the light in the wavelength band of the blue, green, and red laser light and becomes ineffective light, but the other light is reflected and diffused fluorescence. Exit the layer.

The blue, green, and red laser light and fluorescent light are combined with the laser light and fluorescence on the same optical axis by a diffused fluorescent plate provided with an optical thin film layer and a diffused fluorescent layer, and emit white light. The luminous flux of the blue, green, and red laser light emitted from the light source device and the luminous flux of the fluorescent light are configured to be equivalent. In this case, the color gamut roughly includes the color gamut standard DCI. Further, when it is desired to widen the color gamut, a diffused fluorescent plate in which fluorescence emission is suppressed may be used by changing the thickness of the diffused fluorescent layer and the filling rate of the phosphor or diffused particles.

The green laser light source, the red laser light source, and the blue laser light source have shown a configuration in which 24, 24, and 16 semiconductor laser elements are arranged, respectively. However, in order to increase the brightness, a larger number of semiconductor laser elements are used. It may be configured using.

As the emission wavelength of the blue semiconductor laser substrate, a semiconductor laser having a high excitation emission efficiency of 455 nm may be used. Further, both 455 nm and 465 nm semiconductor laser devices may be used.

Although the rotary diffusion fluorescent plate is shown as the dynamic diffusion fluorescent plate, it may be a swing diffusion fluorescent plate that swings the diffusion surface.

As described above, the light source device of the present disclosure uses a dynamic diffused fluorescent plate provided with an optical thin film layer and a diffused fluorescent layer to efficiently produce blue, green, and red laser light sources and fluorescent light without speckle noise. Often, they are synthesized on the same optical axis. Therefore, it is possible to configure a compact light source device with a wide color gamut while eliminating speckle noise and minute luminance unevenness.
(Embodiment 2)
FIG. 6 is a first projection type display device showing the second embodiment of the present disclosure. Three DMDs are used as image forming elements. The light source device is the light source device 42 shown in the first embodiment of the present disclosure.

The first projection type display device further includes a condenser lens 130, 131, a reflection mirror 132, 135, a rod 133, a relay lens 134, a field lens 136, a total reflection prism 137, an air layer 138, and a blue reflection dichroic mirror 140. , A color prism 139 composed of three prisms forming a red-reflecting dichroic mirror 141, a DMD 142, 143, 144, and a projection lens 145.

The combined light of the laser light and the fluorescent light emitted from the light source device 42 is collected by the condenser lenses 130 and 131, reflected by the reflection mirror 132, and then collected by the rod 133. The incident light on the rod 133 is reflected a plurality of times inside the rod, so that the light intensity distribution is made uniform and emitted. The light emitted from the rod 133 is collected by the relay lens 134, reflected by the reflection mirror 135, transmitted through the field lens 136, and incident on the total reflection prism 137. The total reflection prism 137 is composed of two prisms, and a thin air layer 138 is formed on the adjacent surfaces of the prisms. The air layer 138 totally reflects the incident light at an angle equal to or higher than the critical angle. The light from the field lens 136 is reflected by the total reflection surface of the total reflection prism 137 and is incident on the color prism 139. The color prism 139 is composed of three prisms, and a blue-reflecting dichroic mirror 140 and a red-reflecting dichroic mirror 141 are formed on the adjacent surfaces of the prisms. It is separated into blue, red, and green colored light by the blue-reflecting dichroic mirror 140 and the red-reflecting dichroic mirror 141 of the color prism 139, and is incident on the DMD 142, 143, and 144, respectively. The DMDs 142, 143, and 144 deflect the micromirror according to the video signal and reflect the light incident on the projection lens 145 and the light traveling out of the effective direction of the projection lens 145. Here, the DMD micromirror is an example of an illuminated area, and the rod 133, the relay lens 134, the reflection mirror 135, and the field lens 136 constitute an illumination optical system. The light reflected by the DMD 142, 143, 144 passes through the color prism 139 again. In the process of passing through the color prism 139, the separated blue, red, and green colored lights are combined and incident on the total reflection prism 137. Since the light incident on the total reflection prism 137 is incident on the air layer 138 at a critical angle or less, it is transmitted and incident on the projection lens 145. In this way, the image light formed by the DMDs 142, 143, and 144 is magnified and projected onto the screen (not shown).

The luminous flux of each of the blue, green, and red laser beams and the fluorescent luminous flux are configured to be substantially the same luminous flux. The color gamut roughly includes the color gamut standard DCI.

Since DMD is used as the image forming means, it is possible to configure a projection type display device having higher light resistance and heat resistance than the image forming means using a liquid crystal display. Further, since three DMDs are used, color reproduction is good and a bright and high-definition projected image can be obtained.

As described above, the first projection type display device of the present disclosure uses the light source device shown in the first embodiment of the present disclosure. Therefore, it is possible to configure a compact projection type display device with a wide color gamut while eliminating speckle noise and minute luminance unevenness.
(Embodiment 3)
FIG. 7 is a second projection type display device according to the third embodiment of the present disclosure. As the image forming element, an active matrix type transmissive liquid crystal panel having a thin film transistor formed in a pixel region in a TN mode or a VA mode is used. The light source device is the light source device 42 shown in the first embodiment of the present disclosure.

The second projection type display device also includes a condenser lens 198, a reflection mirror 199, a first lens array plate 200, a second lens array plate 201, a polarization conversion element 202, a superimposing lens 203, and a blue reflection dichroic mirror. 204, the green reflection dichroic mirror 205 is a reflection mirror 206, 207, 208, a relay lens 209, 210, a field lens 211, 212, 213, an incident side polarizing plate 214, 215, 216, a liquid crystal panel 217, 218, 219, The emission side polarizing plate 220, 221 and 222, a color synthesis prism 223 composed of a red reflection dichroic mirror and a blue reflection dichroic mirror, and a projection lens 224.

The combined light of the laser light and the fluorescent light emitted from the light source device 42 is incident on the first lens array plate 200 composed of a plurality of lens elements. The luminous flux incident on the first lens array plate 200 is divided into a large number of luminous fluxes. The large number of divided light fluxes converge on the second lens array plate 201 composed of the plurality of lenses. The lens element of the first lens array plate 200 has an aperture shape similar to that of the liquid crystal panels 217, 218, and 219. The focal length of the lens element 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 conjugated relationship. The divided light from the second lens array plate 201 is incident on the polarization conversion element 202. The polarization conversion element 202 is composed of a polarization separation prism and a 1/2 wave plate. The polarization conversion element 202 converts the incident P-polarized and randomly polarized light into S-polarized light, and emits the incident S-polarized light with S-polarized light. The light emitted from the polarization conversion element 202 is incident on 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 and second lens array plates 200 and 201 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 the blue-reflecting dichroic mirror 204 and the green-reflecting dichroic mirror 205, which are color-separating means. The green colored light passes through the field lens 211 and the incident side polarizing plate 214 and is incident on the liquid crystal panel 217. After the blue colored light is reflected by the reflection mirror 206, it passes through the field lens 212 and the incident side polarizing plate 215 and is incident on the liquid crystal panel 218. The red colored light is transmitted, refracted and reflected by the relay lenses 209 and 210 and the reflection mirrors 207 and 208, transmitted through the field lens 213 and the incident side polarizing plate 216, and is incident on the liquid crystal panel 219. The three liquid crystal panels 217, 218, and 219 change the polarization state of the 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 the respective liquid crystal panels 217, 218, and 219. The incident side polarizing plates 214, 215, 216 and the exit side polarizing plates 220, 221 and 222 are combined to modulate the light to form green, blue, and red images. Each color light transmitted through the emitting side polarizing plate 220, 221 and 222 is reflected by the color synthesis prism 223 by the red reflection dichroic mirror and the blue reflection dichroic mirror, respectively, and is combined with the green color light. , Increasing into the projection lens 224. The light incident on the projection lens 224 is magnified and projected on the screen (not shown).

The luminous flux of each of the blue, green, and red laser beams and the fluorescent luminous flux are configured to be substantially the same luminous flux. The color gamut roughly includes the color gamut standard DCI.

Since the image forming means uses three liquid crystal panels that utilize polarization instead of the time division method, color reproduction is good without color breaking, and a bright and high-definition projected image can be obtained. Further, as compared with the case of using three DMD elements, a total reflection prism is not required, and the prism for color synthesis becomes a small prism having a 45-degree incident, so that the projection type display device can be configured in a small size.

As described above, the second projection type display device of the present disclosure uses the light source device shown in the first embodiment of the present disclosure. Therefore, it is possible to configure a compact projection type display device with a wide color gamut while eliminating speckle noise and minute luminance unevenness.

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 smaller and higher-definition projection type display device can be configured.

The present disclosure relates to a light source device of a projection type display device using an image forming means.

20 Blue semiconductor laser substrate 21, 25, 29 Collimated lens array 22 Blue laser light source 23, 27, 31 Heat dissipation plate 24 Green semiconductor laser substrate 26 Green laser light source 28 Red semiconductor laser substrate 30 Red laser light source 32, 33, 140, 204 Blue Reflective dichroic mirror 34, 141 Red reflection dichroic mirror 35, 130, 131, 198 Condenser lens 36 Diffuse plate 37 Glass substrate 38 Optical thin film layer 39 Diffuse fluorescent layer 40 Motor 41 Diffuse fluorescent plate 42 Light source device 50 Binder layer 51 Fluorescent material 132 , 135, 199, 206, 207, 208 Reflective Mirror 133 Rod 134, 209, 210 Relay Lens 136, 211, 212, 213 Field Lens 137 Full Reflection Prism 138 Air Layer 139 Color Prism 142, 143, 144 DMD
145, 224 Projection lens 200 First lens array plate 201 Second lens array plate 202 Polarization conversion element 203 Superimposition lens 205 Green reflection dichroic mirror 214, 215, 216 Incident side polarizing plate 217, 218, 219 Liquid crystal panel 220 , 221 222 Emitting side polarizing plate 223 Color synthesis prism

Claims (8)

Blue, green, red laser light sources and
A dichroic mirror that synthesizes laser light from the blue, green, and red laser light sources,
An optical thin film layer that transmits light in the wavelength band of blue, green, and red laser light and reflects light in the other visible light wavelength band on a glass substrate, and is excited by blue laser light and emits blue light. A light source device including a diffused fluorescent plate having a diffused fluorescent layer for diffusing green and red laser light. The light source device according to claim 1, wherein the diffused fluorescent layer of the diffused fluorescent plate is provided with a yellow phosphor. The light source device according to claim 1, wherein the diffused fluorescent layer of the diffused fluorescent plate includes a diffuser that does not emit light by excitation with a blue laser light. The light source device according to claim 1, wherein the diffuse fluorescent plate is a circular substrate whose rotation can be controlled. The light source device according to claim 1, wherein the blue, green, and red laser light sources are semiconductor lasers. A light source, an illumination optical system that collects light from the light source and illuminates the illuminated area, an image forming element that forms an image according to a video signal, and an image formed by the image forming element are magnified and projected. A projection type display device including a projection lens, wherein the light source is the light source device according to claim 1. The projection type display device according to claim 6, wherein the image forming element is a mirror deflection type digital micromirror device (DMD). The projection type display device according to claim 6, wherein the image forming element is a liquid crystal panel.

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