JP2016153878A - Light source device and projection-type display device - Google Patents

Abstract

A light source device that can greatly improve the output of blue light and that is small in size and high in luminance is provided.
A light source device according to the present disclosure includes a solid-state light source, a dichroic mirror that reflects blue excitation light emitted from the solid-state light source, a retardation plate on which excitation light reflected by the dichroic mirror is incident, and a dichroic mirror that reflects the light. When the excitation light transmitted through the phase difference plate is irradiated, the excitation light is disposed between the fluorescence plate having a fluorescent region that emits fluorescent light and a reflection region that reflects the excitation light, and the retardation plate and the fluorescent plate. And a plurality of condensing lenses for condensing the fluorescent light. Among the plurality of condensing lenses, at least the condensing lens closest to the fluorescent plate is a lens made of a low thermal expansion glass material having a linear expansion coefficient of 32.5 × 10 ⁻⁷ or less.
[Selection] Figure 1

Description

  The present disclosure relates to a projection display device that irradiates an image formed on a digital micromirror device (DMD) or a small light valve with illumination light, and enlarges and projects the image onto a screen by a projection lens, and is used for the projection display device. The present invention relates to a light source device.

  A discharge lamp is widely used as a light source of a projection display device using a mirror-deflection type DMD or a light valve of a liquid crystal panel. Discharge lamps have the problem of short life and low reliability. In order to solve this problem, in recent years, a large number of projection display devices using a solid-state light source such as a semiconductor laser or a light-emitting diode as a light source have been disclosed, and the polarization characteristics of light emitted from the solid-state light source are used. And the light source device which condenses the light from a solid light source compactly and efficiently is disclosed (patent document 1) (patent document 2).

JP 2012-108486 A JP 2013-250494 A

  The present disclosure provides a light source device that can greatly improve the output of blue light and is small and has high brightness.

A light source device according to the present disclosure includes a solid-state light source, a dichroic mirror that reflects blue excitation light emitted from the solid-state light source, a retardation plate on which excitation light reflected by the dichroic mirror is incident, and a retardation plate that is reflected by the dichroic mirror It is placed between a fluorescent plate with a fluorescent region that emits fluorescent light and a reflective region that reflects the excitation light, and between the phase difference plate and the fluorescent plate. A plurality of condensing lenses for condensing. Among the plurality of condensing lenses, at least the condensing lens closest to the fluorescent plate is a lens made of a glass material having a linear expansion coefficient of 32.5 × 10 ⁻⁷ or less.

In addition, the light source device of the present disclosure includes a solid light source, a dichroic mirror that separates light from the solid light source, and combines blue light, green light, and red light, and one light separated by the dichroic mirror. The fluorescent side condenser lens that condenses, the fluorescent plate that emits fluorescent light when excited by the light from the dichroic mirror collected by the fluorescent side condenser lens, and the other light separated by the dichroic mirror is circularly polarized A phase difference plate for conversion, a reflection side condensing lens for condensing light converted into circularly polarized light by the phase difference plate, and a reflection plate for reflecting and returning the light from the reflection side condensing lens . The reflector-side condensing lens adjacent to the reflector is a lens made of a glass material having a linear expansion coefficient of 32.5 × 10 ⁻⁷ or less.

  According to the present disclosure, by providing at least a condensing lens close to the fluorescent plate or the reflecting plate with a low thermal expansion material lens, the efficiency of polarization conversion can be improved and the output of blue light can be greatly improved. Therefore, a compact and high-brightness light source device can be configured. In addition, by using the light source device, a small, bright and long-life projection display device can be realized.

Configuration diagram of light source device according to Embodiment 1 Spectral characteristics of dichroic mirror (A) Configuration diagram of fluorescent plate in Embodiment 1, (b) 3B-3B cross-sectional view shown in (a) The figure which shows the linear expansion coefficient of the glass material for the lens Diagram showing the relative output intensity of blue light with respect to the excitation light intensity in a lens of low thermal expansion glass material The figure which shows the relative output intensity of the blue light with respect to the excitation light intensity in the conventional lens Configuration diagram of light source device according to Embodiment 2 (A) Configuration diagram of fluorescent plate in embodiment 2, (b) 8B-8B cross-sectional view shown in (a) Configuration diagram of a projection display apparatus according to Embodiment 3 Configuration diagram of a projection display apparatus according to Embodiment 4

  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 11 illustrating an embodiment of the present disclosure.

  The solid-state light source unit 23 includes a semiconductor laser 20 and a collimator lens 22 in which eight (2 × 4) squarely arranged in a two-dimensional manner at regular intervals on a heat radiating plate 21. The heat sink 24 is for cooling the solid light source unit 23. The semiconductor laser 20 emits blue light with a wavelength width of 440 nm to 455 nm and emits linearly polarized light. Each semiconductor laser is arranged so that the polarized light emitted from the semiconductor laser 20 becomes S-polarized light with respect to the incident surface of the dichroic mirror 29. FIG. 1 shows the appearance of each light beam emitted from the solid-state light source unit 23 and the polarization direction of light incident on and emitted from the dichroic mirror 29.

  The light emitted from the plurality of semiconductor lasers 20 is condensed by the corresponding collimator lens 22 and converted into a parallel light beam. The light beam group is bent into an optical path by a convex lens 25, a reflection mirror 26, and a concave lens 27, becomes a substantially parallel light beam with a reduced diameter, and is incident on the diffusion plate 28. The diffusing plate 28 is made of glass and diffuses light with a fine uneven shape on the surface. 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 3 degrees, and the diffused light retains the polarization characteristics. The light emitted from the diffuser plate 28 enters a dichroic mirror 29 having an incident angle of 55 degrees.

  FIG. 2 shows the spectral characteristics of the dichroic mirror 29. The spectral characteristics indicate the transmittance with respect to the wavelength. The spectral characteristic is a characteristic of reflecting S-polarized light of semiconductor laser light having a wavelength of 440 to 455 nm with a high reflectance of 95% or more and transmitting P-polarized light at 92% or more. Further, the P-polarized light and the S-polarized light of green and red light each have a characteristic of transmitting with a high transmittance of 92% or more. The wavelength separation width is 31 nm, where the wavelength separation width is the difference between the P-polarized light and the S-polarized light at a transmittance of 50%. In a dichroic mirror with 45 degree incidence, the wavelength separation width of P-polarized light and S-polarized light is generally about 22 nm or less, and since the wavelength separation width is wider at 55 degree incidence, the emission wavelength from the semiconductor laser varies. Even if there exists, the characteristic which reflects the light of S polarization with high reflectance and permeate | transmits P polarization with high transmittance | permeability can be acquired.

  As shown in FIG. 1, the S-polarized blue light reflected by the dichroic mirror 29 enters a quarter-wave plate 30 that is a retardation plate. The quarter wavelength plate 30 is a retardation plate whose phase difference becomes a quarter wavelength near the emission wavelength of the semiconductor laser 20. The quarter wave plate 30 is made of quartz having excellent heat resistance and durability. Incident S-polarized light is converted into circularly polarized light by the quarter-wave plate 30. The light transmitted through the quarter wavelength plate 30 is condensed on the fluorescent plate 37 by the first condenser lens 31 and the second condenser lens 32.

  The light collected by the first condenser lens 31 and the second condenser lens 32 has a spot diameter of 1 mm to 2 mm when 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 and enters the fluorescent screen 37. The diffuser plate 28 diffuses the light so that the spot light has a desired diameter.

  The fluorescent plate 37 is a circularly controllable circular substrate having an aluminum substrate 35 on which a reflective film 34 and a phosphor layer 33 are formed, and a motor 36 at the center. The aluminum substrate 35 of the fluorescent plate 37 is made of aluminum having a high thermal conductivity, and by rotating, the temperature rise of the phosphor layer 33 due to the excitation light can be suppressed and the fluorescence conversion efficiency can be stably maintained.

  FIG. 3A shows the fluorescent region and the reflective region of the fluorescent plate 37. The circular fluorescent plate 37 is divided into three segments, two of which are a fluorescent region coated with a green phosphor 40 and a fluorescent region coated with a red phosphor 41, and the other one segment is reflective. This is a reflection region 42 in which only the film 34 is formed. Y3Al5O12: Ce3 + is used as the green phosphor 40 that fluoresces light containing a green component, and CaAlSiN3: Eu2 + is used as the red phosphor 41 that fluoresces light containing a red component. An aluminum metal film is used for the reflective film 34 in the reflective region 42.

  FIG. 3B is a cross-sectional view taken along the line 3B-3B in FIG. 3A for explaining the configuration in the thickness direction of the fluorescent region and the reflective region. A reflective film 34 is formed on the aluminum substrate 35, and the phosphor layer 33 is printed or applied on the reflective film 34 with a thickness of about 0.1 to 0.2 mm. The light incident on the phosphor layer 33 in the fluorescent region emits green and red light and emits from the fluorescent plate 37. Further, the light emitted toward the reflective film 34 in the fluorescent region is reflected by the reflective film 34 and is emitted from the fluorescent plate 37. On the other hand, circularly polarized blue light incident on the reflective film 34 in the reflective region 42 becomes circularly polarized light in the reverse direction and is emitted from the fluorescent plate 37. As shown in FIG. 1, green and red fluorescent lights that are non-polarized light emitted from the fluorescent plate 37 are condensed by the first condenser lens 31 and the second condenser lens 32 and converted into substantially parallel light. After that, the light passes through the quarter-wave plate 30 and the dichroic mirror 29.

  On the other hand, the blue light reflected by the reflection region 42 maintains the polarization characteristics, becomes circularly polarized light that is opposite to the incident circularly polarized light, and as shown in FIG. 1, the first condenser lens 31 and the second condenser lens. After being condensed at 32 and converted into substantially parallel light, it is converted into P-polarized light by the quarter-wave plate 30. The light converted to P-polarized light passes through the dichroic mirror 29. In this way, the light transmitted through the dichroic mirror 29 is combined with white light. Based on the value of the wavelength conversion efficiency from excitation light to each fluorescent light, the intensity ratio of green, red and blue light is adjusted by adjusting the three segments to an appropriate division ratio (division angle). White light with white balance can be obtained.

  The first condensing lens 31 and the second condensing lens 32 efficiently condense light emitted from the fluorescent plate 37 with characteristics close to completely diffused light. Light of approximately ± 70 degrees is collected by the two condenser lenses of the second condenser lens 32 and converted to parallel light.

  The second condenser lens 32 is a lens having a diameter of 20 mm, and is arranged in the vicinity of approximately 1.5 mm from the fluorescent plate 37. For this reason, the light intensity distribution on the plane side of the second condenser lens 32 is a Gaussian distribution having a diameter of about 4 mm, and the light density is higher than that of other optical devices, resulting in a high temperature. Further, the temperature difference between the central portion and the peripheral portion of the second condenser lens 32 is also large. A lens having a high temperature and a large temperature difference causes birefringence due to thermal stress, and circularly polarized light becomes elliptically polarized light. As a result, the efficiency of polarization conversion is reduced, and the blue light transmitted through the dichroic mirror 29 is reduced. Output decreases.

FIG. 4 shows the linear expansion coefficient of 102 types of optical glass (crown, flint type), which is a general glass material that can be used as a lens material, and the linear expansion coefficients of 3 types of low thermal expansion glass materials. As shown in FIG. 4, the optical glass 102 has a linear expansion coefficient of at least 60 × 10 ⁻⁷ , and when optical glass having such a linear expansion coefficient is used for a lens, The effect is extremely large. Therefore, it is necessary to select a lens glass material having a linear expansion coefficient sufficiently smaller than this value.

Therefore, was examined various materials that can be used as a lens material, a sufficiently small low thermal expansion glass material than the linear expansion coefficient of 60 × 10 ^-7, the linear expansion coefficient of 32.5 × 10 ^-7 lens There is a glass material. As the glass material for lenses having a linear expansion coefficient of 32.5 × 10 ⁻⁷ , a glass material of Pyrex (registered trademark and the like) and Tempax (registered trademark and the same) can be used.

  It has been confirmed that when such a low thermal expansion glass material is used, the occurrence of birefringence is suppressed even at a relatively high temperature, and the polarized light is not substantially affected.

Pyrex and Tempax lenses are relatively inexpensive, but as shown in FIG. 4, synthetic quartz glass has a linear expansion coefficient of 5.0 × 10 ^{−7 to} 5.9 × 10 ^−7, which is even more than these. small. Therefore, although the lens becomes relatively expensive, synthetic quartz glass has excellent properties as a low thermal expansion glass material even at higher temperatures. For this reason, it is more preferable to use synthetic quartz glass for the lens.

  FIG. 5 shows the relative output intensity of the blue light with respect to the excitation light intensity at the fluorescent plate 37 in the case of using a low thermal expansion glass material lens. As the glass material of the second condenser lens 32, synthetic quartz glass of low thermal expansion glass material is used. As shown in FIG. 5, the intensity of the blue light emitted from the dichroic mirror 29 increases in proportion to the intensity of the excitation light to the fluorescent plate 37.

FIG. 6 shows the relative output intensity of blue light with respect to the excitation light intensity at the fluorescent plate 37 when a general optical glass lens is used. As the glass material of the second condenser lens 32, a lens having a linear expansion coefficient of 72 × 10 ⁻⁷ is used. As shown in FIG. 6, when the intensity of the excitation light to the fluorescent plate 37 increases, the birefringence at the second condenser lens 32 decreases the conversion efficiency of the polarization direction, and the blue light output from the dichroic mirror 29 is output. Strength decreases.

  From FIG. 5 and FIG. 6, when the output intensity of the blue light is compared between the synthetic quartz glass of the low thermal expansion glass material and the general optical glass material, the second condenser lens 32 is relatively more in the synthetic quartz glass material. When the excitation light intensity is 20, the output intensity of blue light is 1.14 times, and when the excitation light intensity is 40, the output intensity of blue light is 1.4 times. By using a low thermal expansion glass material for the second condenser lens 32, the output intensity of blue light can be significantly improved. When birefringence occurs in the first condenser lens 31, a lens made of a low thermal expansion glass material may be used for the first condenser lens 31. In this case, the blue light output can be further improved.

  The fluorescent plate 37 shown in FIG. 3 is divided into three segments, but is divided into four segments of a red phosphor, a green phosphor, a Ce-activated YAG-based yellow phosphor, and a reflective region to which no phosphor is applied. May be. By using a yellow phosphor, white balance is further improved and bright white light can be obtained.

  In order to increase the wavelength separation width of P-polarized light and S-polarized light, the dichroic mirror 29 uses the dichroic mirror 29 having an incident angle of 55 degrees, but a dichroic mirror having an incident angle of 45 degrees may be used. Although one solid light source unit 23 is used in FIG. 1, a plurality of solid light source units may be combined by a mirror and used.

As described above, in the light source device 11 according to the present embodiment, at least the second condenser lens 32 that is close to the fluorescent plate 37 includes a low thermal expansion glass material lens having a linear expansion coefficient of 32.5 × 10 ⁻⁷ or less. Therefore, the birefringence accompanying the high temperature of the condenser lens can be eliminated, the output of blue light can be improved, and a high-luminance light source device can be configured.

(Embodiment 2)
FIG. 7 is a configuration diagram of the light source device 12 according to the second embodiment of the present disclosure.

  The solid-state light source unit 53 includes a semiconductor laser 50 and a collimating lens 52 in which 24 (6 × 4) are arranged in a two-dimensional manner at regular intervals on a heat radiating plate 51. The heat sink 54 is for cooling the solid light source unit 53. The semiconductor laser 50 emits blue light at a wavelength of 440 nm to 455 nm and emits linearly polarized light. The semiconductor laser 50 is arranged with respect to the incident surface of the dichroic mirror 59 such that about 80% of the number of semiconductor lasers emits S-polarized light and about 20% emits P-polarized light. The dichroic mirror 59 has a characteristic of reflecting S-polarized light and transmitting P-polarized light. In FIG. 7, the appearance of each light beam emitted from the solid light source unit 53 is also shown.

  The light emitted from the plurality of semiconductor lasers 50 is condensed by the corresponding collimator lens 52 and converted into a parallel light beam 55. The luminous flux 55 group is further reduced in diameter by a convex lens 56 and a concave lens 57 and is incident on the diffusion plate 58. The diffusing plate 58 is made of glass and diffuses light with a fine uneven shape on the surface. 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 3 degrees, and the diffused light retains the polarization characteristics. The light emitted from the diffusion plate 58 enters the dichroic mirror 59.

  The S-polarized light beam incident on the dichroic mirror 59 is reflected by the dichroic mirror 59. The S-polarized light beam reflected by the dichroic mirror 59 is condensed by the first condenser lens 60 and the second condenser lens 61, and the diameter at which the light intensity is 13.5% of the peak intensity is 1 mm to 2 mm. The light is superimposed on the spot light and enters the fluorescent screen 66. The 1st condensing lens 60 and the 2nd condensing lens 61 comprise the fluorescence side condensing lens. The diffuser plate 58 diffuses the light so that the spot light has a desired diameter.

  8A is a configuration diagram of the fluorescent plate 66, and FIG. 8B is an 8B-8B cross-sectional view shown in FIG. 8A. The fluorescent plate 66 is an aluminum substrate 64 on which a reflective film 63 and a phosphor layer 62 are formed, and a circular substrate that can be controlled in rotation and includes a motor 65 at the center. The reflection film 63 of the fluorescent plate 66 is a metal film that reflects visible light. In the phosphor layer 62, a Ce-activated YAG yellow phosphor that is excited by blue light and emits yellow light containing a green component and a red component is formed. A typical chemical structure of the crystal matrix of this phosphor is Y3Al5O12. The phosphor layer 62 is formed in an annular shape. The phosphor layer 62 excited by the spot light emits yellow light including green component light and red component light. The aluminum substrate 64 of the fluorescent plate 66 is aluminum having high thermal conductivity, and by rotating, the temperature rise of the phosphor layer 62 due to excitation light can be suppressed, and the fluorescence conversion efficiency can be stably maintained.

  The light incident on the phosphor layer 62 fluoresces green and red light components, and exits the fluorescent plate 66. Further, the light emitted to the reflective film 63 side is reflected by the reflective film 63 and is emitted from the fluorescent plate 66. The green and red light emitted from the fluorescent plate 66 is collected by the first condenser lens 60 and the second condenser lens 61, converted into substantially parallel light, and then transmitted through the dichroic mirror 59. In this case, since the green and red light emitted from the fluorescent plate 66 does not have polarization characteristics, it is not necessary to use a low thermal expansion glass material for the second condenser lens 61.

  On the other hand, the P-polarized light beam incident on the dichroic mirror 59 is transmitted through the dichroic mirror 59. The P-polarized blue light that passes through the dichroic mirror 59 is incident on a quarter-wave plate 67 that is a phase difference plate. The quarter wavelength plate 67 is a retardation plate whose phase difference becomes a quarter wavelength near the emission wavelength of the semiconductor laser 50. The quarter wave plate 67 is made of quartz. Incident P-polarized light is converted into circularly polarized light by the quarter-wave plate 67.

  The light transmitted through the quarter wavelength plate 67 is condensed by the third condenser lens 68 and the fourth condenser lens 69. The focal lengths of the third condenser lens 68 and the fourth condenser lens 69 are approximately the same as those of the first condenser lens 60 and the second condenser lens 61, and a condensing spot is formed in the vicinity of the reflector 70. . The spot diameter to be collected is about the same as the excitation light. The third condenser lens 68 and the fourth condenser lens 69 constitute a reflector side condenser lens.

  The reflecting plate 70 is made of glass, and the surface on the condenser lens 69 side is a surface with a fine uneven shape for diffusing light. On the other surface, a reflective film of a metal film or a dielectric film is formed. The reason why the reflection plate 70 is configured as a diffuse reflection surface is to ensure speckle reduction and luminance uniformity of laser light. The reflection plate 70 is a diffusion surface in a range that maintains the polarization characteristics of blue light. The light reflected by the reflecting plate 70 is inverted in the phase of circularly polarized light, and is condensed again by the third condenser lens 68 and the fourth condenser lens 69.

  The third condensing lens 68 and the fourth condensing lens 69 condense light from the reflecting plate 70 efficiently, so that the aspherical third condensing lens 68 and the spherical fourth condensing lens 69 are collected. These two condensing lenses condense light of approximately ± 70 degrees and convert it into parallel light.

The fourth condenser lens 69 is a lens having a diameter of 20 mm, and is arranged in the vicinity of approximately 1.5 mm from the reflecting plate 70. For this reason, the light intensity distribution on the plane side (the reflection plate 70 side) of the fourth condenser lens 69 is a Gaussian distribution with a diameter of about 4 mm, and the light density is higher and the temperature is higher than other optical devices. Further, the temperature difference between the central portion and the peripheral portion of the fourth condenser lens 69 is also large. A lens having a high temperature and a large temperature difference causes birefringence due to thermal stress, and circularly polarized light becomes elliptically polarized light. As a result, the efficiency of polarization conversion is reduced, and the blue light transmitted through the dichroic mirror 59 is reduced. Output decreases. Therefore, the fourth condenser lens 69 is a low thermal expansion glass material lens using synthetic quartz glass having a linear expansion coefficient of 5 × 10 ⁻⁷ so that birefringence does not occur even when the temperature is increased. When birefringence occurs in the third condenser lens 68, the output of blue light can be further improved by using a low thermal expansion glass material for the third condenser lens 68 as well.

  The light emitted from the third condenser lens 68 and the fourth condenser lens 69 enters the quarter wavelength plate 67. Light incident on the quarter-wave plate 67 is converted from circularly polarized light to S-polarized light, and S-polarized blue light is reflected by the dichroic mirror 59.

  In this way, the green and red component fluorescent light from the fluorescent plate 66 and the blue light that has the polarization characteristics and is efficiently condensed and uniformed are synthesized by the dichroic mirror 59 and emitted as white light. . Good white balance emission characteristics can be obtained by yellow light containing green and red components of fluorescent light emission and blue light of the semiconductor laser 50. Even if this emission spectral characteristic is separated into three primary color lights of blue, green and red in the optical system of the projection display device, monochromatic light having a desired chromaticity coordinate can be obtained.

  Although one solid light source unit 53 is used in FIG. 7, a plurality of solid light source units may be combined by a mirror and used. The dichroic mirror 59 has been described using the characteristics of blue 80% reflection, green and red transmission, but may be the characteristics of blue 80% transmission green and red reflection.

As described above, in the light source device 12 according to the present embodiment, at least the fourth condensing lens 69 in the vicinity of the reflecting plate 70 has a low thermal expansion glass material lens having a linear expansion coefficient of 32.5 × 10 ⁻⁷ or less. Therefore, the birefringence accompanying the high temperature of the condenser lens can be eliminated, the output of blue light can be improved, and a high-luminance light source device can be configured.

(Embodiment 3)
FIG. 9 shows the projection display apparatus of the present embodiment. One DMD is used as the image forming means. DMD is an example of an image forming element.

  The light source device 11 includes a solid state light source unit 23 including a blue semiconductor laser 20, a heat radiating plate 21, and a collimating lens 22. The heat sink 24 is for cooling the solid light source unit 23. The light source device 11 further includes a lens 25 and a lens 27, a reflection mirror 26, a diffusion plate 28, a dichroic mirror 29, a ¼ wavelength plate 30, a first condenser lens 31, a second condenser lens 32, and a fluorescent plate 37. . The fluorescent plate 37 includes an aluminum substrate 35 on which a phosphor layer 33 and a reflective film 34 are formed, and a motor 36. The above configuration is the same as that of the light source device 11 according to the first embodiment of the present disclosure.

  The light emitted from the light source device 11 emits red, green, and blue light in time series by the rotation of the fluorescent plate 37. Light from the light source device 11 enters the first lens array plate 100 composed of a plurality of lens elements. The light beam incident on the first lens array plate 100 is divided into a number of light beams. A large number of the divided light beams converge on the second lens array plate 101 composed of a plurality of lenses. The lens elements of the first lens array plate 100 have an opening shape similar to that of the DMD 106. The focal length of the lens elements of the second lens array plate 101 is determined so that the first lens array plate 100 and the DMD 106 have a substantially conjugate relationship.

  The light emitted from the second lens array plate 101 enters the superimposing lens 102. The superimposing lens 102 is a lens for superimposing and illuminating the light emitted from each lens element of the second lens array plate 101 on the DMD 106. The light from the superimposing lens 102 is reflected by the reflecting mirror 103 and then enters the field lens 104. The field lens 104 condenses the illumination light on the projection lens 107 efficiently. Illumination light from the field lens 104 enters the total reflection prism 105. The total reflection prism 105 is composed of two prisms. A thin air layer is formed on the adjacent surfaces of the prisms, and the air layer totally reflects light incident at an angle greater than the critical angle. The illumination light from the field lens 104 is totally reflected to illuminate the DMD 106 and transmit the projection light emitted from the DMD 106.

  The light incident on the DMD 106 deflects only the light beam necessary for image formation according to the video signal, passes through the total reflection prism 105, and then enters the projection lens 107. The projection lens 107 enlarges and projects the image light modulated and formed by the DMD 106. In this embodiment, since one DMD is used and the light source device 11 according to the first embodiment of the present disclosure is used as the light source device 11, a small, bright and long-life projection display device can be configured.

  Although two lens array plates are used as an integrator optical system for ensuring the uniformity of the projected image, a rod may be used.

As described above, the projection display apparatus according to the present embodiment includes a plurality of solid-state light sources, a dichroic mirror that reflects blue light from the solid-state light source, a phase difference plate, and a fluorescent plate that excites fluorescence with light from the dichroic mirror. And a light source device including a condensing lens for condensing excitation light and fluorescent light. In this light source device, at least a condenser lens adjacent to the fluorescent plate is provided with a lens made of a low thermal expansion glass material having a linear expansion coefficient of 32.5 × 10 ⁻⁷ or less. Since the present embodiment is a projection display device configured using this light source device, an integrator illumination optical system using a lens array, and one DMD, it is small in size and has high uniformity in the projected image. Bright projection display can be configured.

(Embodiment 4)
FIG. 10 shows the projection display apparatus of the present embodiment. Three DMDs are used as image forming means.

  The light source device 12 includes a solid state light source unit 53 including a blue semiconductor laser 50, a heat radiating plate 51, and a collimating lens 52. The heat sink 54 is for cooling the solid light source unit 53. The light from the solid light source unit 53 is applied to the fluorescent plate 66 by the lens 56, the lens 57, the diffusion plate 58, the dichroic mirror 59, the first condenser lens 60, and the second condenser lens 61. The fluorescent plate 66 includes an aluminum substrate 64 on which a reflective film 63 and a phosphor layer 62 are formed, and a motor 65. The light from the solid-state light source unit is further transmitted through the dichroic mirror 59 and transmitted through the quarter-wave plate 67, the third condenser lens 68, and the fourth condenser lens 69 and is incident on the reflector 70. Is done. The above is the same configuration as that of the light source device 12 according to the second embodiment of the present disclosure.

  White light from the light source device 12 enters the lens 120 and is condensed on the rod 121. Light incident on the rod 121 is reflected a plurality of times inside the rod, so that the light intensity distribution is uniformed and emitted. Light emitted from the rod 121 is collected by the relay lens 122, reflected by the reflection mirror 123, then transmitted through the field lens 124, and enters the total reflection prism 125.

  The total reflection prism 125 is composed of two prisms, and a thin air layer 126 is formed on the adjacent surfaces of the prisms. The air layer 126 totally reflects light incident at an angle greater than the critical angle. Light from the field lens 124 is reflected by the total reflection surface of the total reflection prism 125 and enters the color prism 127.

  The color prism 127 is composed of three prisms, and a blue reflecting dichroic mirror 128 and a red reflecting dichroic mirror 129 are formed on the adjacent surfaces of the prisms. The light is separated into blue, red, and green light by the blue reflecting dichroic mirror 128 and the red reflecting dichroic mirror 129 of the color prism 127, and enters the DMDs 130, 131, and 132, respectively.

  DMDs 130, 131, and 132 deflect the micromirror according to the video signal, and reflect the light into the light incident on the projection lens 133 and the light traveling outside the effective range of the projection lens 133. The light reflected by the DMDs 130, 131, and 132 passes through the color prism 127 again. In the process of passing through the color prism 127, the separated blue, red, and green lights are combined and enter the total reflection prism 125. Since the light incident on the total reflection prism 125 is incident on the air layer 126 at a critical angle or less, it is transmitted and incident on the projection lens 133.

  In this manner, the image light formed by the DMDs 130, 131, and 132 is enlarged and projected on a screen (not shown). Since the light source device 12 is composed of a plurality of solid light sources and emits white light with high brightness and good white balance, it is possible to realize a projection display device with long life and high brightness. 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.

  Although DMD is used as the image forming means, a transmissive liquid crystal panel may be used. The transmissive liquid crystal panel has low light resistance and heat resistance to DMD, but does not require a total reflection prism, and the color composition prism is a small prism with a 45-degree incidence, so the projection display device is small. Can be configured.

  As described above, the projection display apparatus according to the present embodiment includes a plurality of solid-state light sources, a dichroic mirror that separates light from the solid-state light sources and combines blue light, green, and red light, A second condenser lens and a fluorescent plate that is excited by light from the dichroic mirror to fluoresce and reflect are provided. Further, since the light source device including the phase difference plate on which the other light separated by the dichroic mirror is incident, the third and fourth condenser lenses, and the reflection plate is used, a small and high-brightness projection display device is provided. Can be configured.

  The present disclosure relates to a projection display apparatus using an image forming unit.

DESCRIPTION OF SYMBOLS 11,12 Light source device 20,50 Semiconductor laser 21,51 Heat sink 22,52 Collimating lens 23,53 Solid light source unit 24,54 Heat sink 25,27,56,57,120 Lens 26,103,123 Reflection mirror 28,58 Diffusion plate 29, 59 Dichroic mirror 30, 67 1/4 wavelength plate 31, 32, 60, 61, 68, 69 Condensing lens 33, 62 Phosphor layer 34, 63 Reflective film 35, 64 Aluminum substrate 36, 65 Motor 37 , 66 Fluorescent plate 40 Green phosphor 41 Red phosphor 42 Reflecting area 70 Reflecting plate 100 First lens array plate 101 Second lens array plate 102 Superimposing lens 104, 124 Field lens 105, 125 Total reflection prism 106, 130, 131,132 DMD
107, 133 Projection lens 121 Rod 122 Relay lens 126 Air layer 127 Color prism 128 Blue reflection dichroic mirror 129 Red reflection dichroic mirror

Claims (11)

A solid light source;
A dichroic mirror that reflects blue excitation light emitted from the solid-state light source;
A retardation plate on which the excitation light reflected by the dichroic mirror is incident;
A fluorescent plate provided with a fluorescent region that emits fluorescent light when irradiated with the excitation light reflected by the dichroic mirror and transmitted through the retardation plate, and a reflective region that reflects the excitation light;
A plurality of condensing lenses that are arranged between the retardation plate and the fluorescent plate and condense the excitation light and the fluorescent light; and
The light source device, wherein at least the condensing lens closest to the fluorescent plate among the plurality of condensing lenses is a lens made of a glass material having a linear expansion coefficient of 32.5 × 10 ⁻⁷ or less. A solid light source;
A dichroic mirror that separates light from the solid-state light source and combines blue light, green light, and red light;
A fluorescent-side condenser lens that condenses one of the lights separated by the dichroic mirror;
A fluorescent plate that is excited by light from the dichroic mirror collected by the fluorescent-side condenser lens to emit fluorescent light;
A phase difference plate that converts the other light separated by the dichroic mirror into circularly polarized light;
A reflector-side condensing lens that condenses the light converted into the circularly polarized light by the retardation plate;
A reflection plate that reflects and returns the light from the reflection side condenser lens,
The light source device, wherein the reflector side condensing lens adjacent to the reflector is a lens made of a glass material having a linear expansion coefficient of 32.5 × 10 ⁻⁷ or less.   The light source device according to claim 1, wherein the glass material is synthetic quartz glass.   The light source device according to claim 1, wherein the glass material is a Pyrex (registered trademark) material or a Tempax (registered trademark) material.   The light source device according to claim 1, wherein the dichroic mirror is incident at 55 degrees.   The light source device according to claim 1, wherein the solid-state light source is a blue semiconductor laser.   The light source device according to claim 1, wherein the light emitted from the solid light source is linearly polarized light.   The light source device according to claim 1, wherein the retardation plate is a ¼ wavelength plate.   The light source device according to claim 1, wherein the fluorescent plate can be rotationally controlled. The light source device according to claim 1 or 2,
An illumination optical system for condensing light from the light source device;
An image forming element that forms an image according to a video signal from the light collected by the illumination optical system;
A projection display device comprising: a projection lens that projects an image formed by the image forming element.   The projection display apparatus according to claim 10, wherein the image forming element is a digital micromirror device (DMD).