CN107608166A - Light supply apparatus and projection type image display apparatus - Google Patents

Abstract

Provided are a light source device using polarization properties of light emitted from a solid-state light source and using a low-cost phase difference plate with excellent durability, and a projection display device using the light source device. In the light source device (40), the P-polarized blue light emitted from the semiconductor laser (21) passes through the condenser lens (23), the lens (26), the lens (27), and the first diffuser plate (28) and enters the dichroic mirror (29). The dichroic mirror (29) transmits part of the P-polarized blue light and reflects the remaining light. The blue light transmitted through the dichroic mirror (29) is condensed by the condensing lens (36) to become converging light, and passes through the quarter-wave plate (38) to enter the reflection plate (39). The blue light reflected by the reflector and turned into divergent light passes through the quarter-wave plate (38) and enters the condenser lens (36) to be converted into parallel light.

Description

Light source device and projection display device

technical field

The present invention relates to a projection display device that irradiates an image formed on a small light bulb with illumination light, and projects it on a screen through a projection lens in an enlarged manner.

Background technique

As light sources for projection display devices using mirror deflection type digital micromirror devices (DMDs) and light bulbs for liquid crystal panels, many light source devices using solid-state light sources such as long-life semiconductor lasers and light emitting diodes are disclosed. Among them, Patent Document 1 discloses a light source device that is compact and efficiently condenses light from a solid-state light source by utilizing the polarization characteristics of light emitted from the solid-state light source.

In addition, Patent Document 2 discloses a compact and highly efficient light source device using a half-wave plate that converts the polarization orientation of light from a fixed light source and converts the light incident to the The P polarization component and the S polarization component of the color mirror are controlled to a certain ratio.

prior art literature

patent documents

Patent Document 1: JP-A-2012-137744

Patent Document 2: JP Unexamined Publication No. 2014-209184

Contents of the invention

The present invention provides a light source device utilizing the polarization characteristics of light emitted from a solid-state light source and using a highly durable and low-cost phase difference plate, and a projection display device using the light source device.

The first light source device of the present invention is provided with: a solid light source; a condensing element for condensing light from the solid light source; a retardation plate for converting linearly polarized light into circularly polarized light; Between the element and the reflector, it is arranged at a position where convergent light or divergent light is incident.

In addition, the 2nd light source device of the present invention has: solid light source; Transform the polarization orientation of the light from solid light source, the phase difference plate that the light of P polarization and S polarization component is controlled to a certain ratio; The dichroic mirror for polarization separation, the retardation plate is arranged between the solid light source and the dichroic mirror, and is arranged at the incident position of converging light or divergent light.

Invention effect

According to the present invention, since a small and inexpensive light source device can be configured by arranging and configuring the retardation plate at a light-condensing position, a long-life, bright, and low-cost projection display device can be realized.

Description of drawings

FIG. 1 is a configuration diagram of a light source device in Embodiment 1 of the present invention.

FIG. 2 is a graph showing the spectral characteristics of the dichroic mirror in Embodiment 1. FIG.

FIG. 3 is a graph showing the angle-dependent characteristics of the polarized light transmittance of the retardation film.

4 is a configuration diagram of a light source device in Embodiment 2 of the present invention.

FIG. 5 is a graph showing spectral characteristics of a dichroic mirror in Embodiment 2. FIG.

6 is a configuration diagram of a projection display device in Embodiment 3 of the present invention.

7 is a configuration diagram of a projection display device in Embodiment 4 of the present invention.

Symbol Description

21, 51 semiconductor laser

22, 52 heat sink

23, 53 condenser lens

24, 54 heat sink

25, 55 beams

26, 27 lens

28, 60 1st diffuser plate

29, 61 dichroic mirror

30, 31, 36, 56, 59, 62, 63, 68 condenser lens

32, 64 Phosphor layer

33, 65 aluminum substrate

34, 66 electric motor

35, 67 fluorescent plate

37, 69 Second diffusion plate

38 quarter wave plate

39, 71 reflector

40, 72 light source device

57 reflector

58 half wave plate

70 quarter wave plate

80, 90 Projection display device

100 condenser lens

101 sticks

102, 209, 210 relay lens

103, 206, 207, 208 Reflectors

104, 211, 212, 213 field lenses

105 total reflection prism

106 air layer

107 colored prisms

108, 204 blue reflective dichroic mirror

109 red reflecting dichroic mirror

110, 111, 112 DMDs

113, 224 projection lens

200 1st lens array plate

201 2nd lens array plate

202 Polarization conversion element

203 Overlapping lens

205 green reflective dichroic mirror

214, 215, 216 Incident side polarizer

217, 218, 219 LCD panel

220, 221, 222 Exit side polarizing plate

223 color composite prism

Detailed ways

Hereinafter, embodiments will be described in detail with reference to the drawings as appropriate. However, an overly detailed description may be omitted. For example, detailed descriptions of already well-known items and repeated descriptions of substantially the same configurations may be omitted. This is to avoid the following description from being too lengthy and to make it easy for those skilled in the art to understand.

In addition, the drawings and the following descriptions are provided for those skilled in the art to fully understand the present invention, and they are not intended to limit the subject matter described in the claims.

(Embodiment 1)

FIG. 1 is a configuration diagram of a light source device according to Embodiment 1 of the present invention. The light source device 40 of Embodiment 1 includes: a semiconductor laser 21 as a solid light source, a heat sink 22, a condenser lens 23, a heat sink 24, a lens 26, a lens 27, a first diffusion plate 28, a dichroic mirror 29, and a first Condensing lenses 30 and 31 of the converging element, a fluorescent plate 35 composed of an aluminum substrate 33 on which a reflective film and a phosphor layer 32 are formed, and a motor 34, a converging lens 36 as a second converging element, and a second diffuser plate 37. A quarter-wave plate 38 as a phase difference plate, and a reflection plate 39. FIG. 1 shows the state of each light beam 25 emitted from the solid-state light source and the polarization direction of the light entering and exiting the dichroic mirror 29 .

Twenty-four (6×4) semiconductor lasers 21 and condenser lenses 23 arranged in a square shape are two-dimensionally arranged on the heat sink at constant intervals. The heat sink 24 is used to cool the semiconductor laser 21 . The semiconductor laser 21 emits blue light having a wavelength width of 447 nm to 462 nm, and emits linearly polarized light. Each semiconductor laser is arranged so that the polarized light emitted from the semiconductor laser 21 becomes P-polarized light on the incident plane of the dichroic mirror 29 .

The light emitted from the plurality of semiconductor lasers 21 passes through the corresponding condensing lenses 23 , and is respectively condensed and converted into parallel light beams 25 . The light beams 25 are further reduced in diameter by the convex lens 26 and the concave lens 27 , and enter the first diffuser plate 28 . The first diffuser plate 28 is made of glass, and diffuses light by the fine concavo-convex shape on the surface. The diffusion angle, which is the half-value angle width that becomes 50% of the maximum intensity of the diffused light, is as small as about 3 degrees, and the polarization characteristics are maintained. The light emitted from the first diffuser 28 enters the dichroic mirror 29 .

The spectral characteristics of the dichroic mirror are shown in FIG. 2 . Spectral characteristics show transmittance with respect to wavelength. The spectroscopic characteristics of the dichroic mirror are to transmit (18% on average) and reflect (82% on average) the P polarization of the semiconductor laser with a wavelength of 447 to 462nm, and to reflect the S polarization at a high reflectance of 95% or more. . Furthermore, both P polarization and S polarization of green light and red light are transmitted with a high transmittance of 96% or more.

82% of the P-polarized blue light reflected by the dichroic mirror 29 is condensed by the condenser lenses 30 and 31, and if the diameter at which the light intensity becomes 13.5% of the peak intensity is defined as the spot diameter, the superimposed light becomes The spot light with a spot diameter of 1.5 mm to 2.5 mm enters the fluorescent plate 35 . The first diffuser plate 28 diffuses the light so that the diameter of the spot light becomes a desired diameter.

The phosphor plate 35 is a controllable circular substrate including an aluminum substrate 33 on which a reflective film and a phosphor layer 32 are formed, and a motor 34 in the center. The reflective film of the phosphor plate 35 is a metal film or a dielectric film that reflects visible light, and is formed on an aluminum substrate. Further, the phosphor layer 32 is formed on the reflective film. A Ce-activated YAG-based yellow phosphor that is excited by blue light and emits yellow light including green and red components is formed in the phosphor layer 32 . A representative chemical structure of the crystal matrix of the phosphor is Y ₃ Al ₅ O ₁₂ . Phosphor layer 32 is formed in an annular shape. Phosphor layer 32 excited by spot light emits yellow light including light of green and red components. The phosphor plate 35 is an aluminum substrate, and by rotating the phosphor plate 35 , the temperature rise of the phosphor layer 32 caused by the excitation light can be suppressed, and the phosphor conversion efficiency can be stably maintained.

The light incident on the phosphor layer 32 fluoresces green and red color lights and is emitted from the phosphor plate 35 . In addition, the light emitted toward the reflective film side is reflected by the reflective film and emitted from the fluorescent plate 35 . The green light and red light emitted from the fluorescent plate 35 become natural light (non-polarized light), which is again condensed by the condensing lenses 30 and 31 , converted into approximately parallel light, and transmitted through the dichroic mirror 29 .

On the other hand, 18% of the P-polarized blue light transmitted through the dichroic mirror 29 enters the condensing lens 36 as the second condensing element, and is condensed to become converged light. The focal length of the condensing lens 36 is such that the condensing angle is 40 degrees or less, and a condensing point is formed in the vicinity of the reflection plate 39 . The condensed light condensed by the condensing lens 36 enters the second diffuser plate 37 . The second diffusion plate 37 diffuses the incident light, uniformizes the light intensity distribution, and eliminates speckle of the laser light. The second diffusion plate 37 has a diffusion surface formed of fine concavo-convex shapes on the glass surface of the thin plate. The second diffusion plate 37 is a diffusion plate in which the primary transmitted light on the diffusion surface has a diffusion angle of approximately 4 degrees and maintains polarization characteristics. The light transmitted through the second diffuser 37 enters a quarter-wave plate 38 as a phase difference plate. The quarter-wave plate 38 is a retardation plate with a phase difference of 1/4 wavelength around the emission center wavelength of the semiconductor laser 21 .

When the P polarization direction in FIG. 1 is set to 0 degrees, the quarter wave plate 38 arranges the optical axis at 45 degrees. The quarter-wave plate 38 is a thin-film retardation plate utilizing birefringence by oblique vapor deposition of a dielectric material (see JP 2012-242449 A). Thin-film retardation plates are made of inorganic materials, and are as durable and reliable as inorganic optical crystals such as crystals. In addition, since the thin-film wavelength plate is laminated with a film thickness sufficiently thinner than the wavelength of light, it becomes a retardation plate having one optical axis in the entire obliquely deposited layer. Therefore, the change of the phase difference with respect to the incident angle is very small compared with a phase difference plate of an inorganic optical crystal such as crystal.

FIG. 3 shows an example of the angular dependence of the polarized light transmittance in a film retardation film (solid line) and a crystal retardation film (dashed line). The transmittance of one linearly polarized light component after the linearly polarized light is made incident on the retardation plate and converted into circularly polarized light is defined as the polarized light transmittance, and the polarized light transmittance with respect to the incident angle is shown. Normalization was performed by setting the polarized light transmittance when the incident angle was 0 degrees to 1.0. The polarized light transmittance of the film retardation film decreased by 6% in the range of the incident angle of ±30 degrees, while the polarized light transmittance of the crystal retardation plate decreased by 12% in the range of the incident angle of ±5 degrees. Since the film retardation film has a very small incidence angle dependence, it can efficiently convert incident linearly polarized light into circularly polarized light even if it is placed at a position where converging or diverging light is incident. In addition, since it is arranged at a position where converging light or diverging light is incident, the size of the quarter-wave plate 38 can be reduced to 1/2 or less in size compared with the conventional case where it is placed at a position where parallel light is incident. Quarter wave plates can significantly reduce costs.

The light transmitted through the quarter-wave plate 38 and converted into circularly polarized light is reversed in phase by the reflector 39 formed with a reflective film such as aluminum or a dielectric multilayer film, and becomes divergent light as reversed circularly polarized light. After passing through a quarter-wave plate 38, it is converted into S polarized light. Furthermore, since no member disturbing the polarized light is arranged between the quarter-wave plate 38 and the reflecting plate 39, it is possible to efficiently convert the P-polarized light into the S-polarized light.

The S-polarized light converted by the quarter-wave plate 38 is diffused again by the second diffuser 37 , converted into parallel light by the condenser lens 36 , and reflected by the dichroic mirror 29 .

In this way, the fluorescent light from the fluorescent plate 35 and the efficiently polarized blue light are synthesized by the dichroic mirror 29 and emitted as white light. A light emission characteristic with a good white balance can be obtained by fluorescently emitting yellow light including green and red components and blue light from the semiconductor laser 21 . Even if this emission spectrum characteristic is separated into three primary color lights of blue, green, and red by the optical system of the projection display device, monochromatic light with desired chromaticity coordinates can be obtained.

The quarter-wave plate has been described using a thin-film retardation plate, but a microstructural retardation plate utilizing birefringence caused by a fine periodic structure equal to or less than the wavelength of light may also be used. The fine-structure retardation plate has a fine structure equal to or less than the wavelength of light, and thus, like the thin-film retardation film shown in FIG. 3 , the incident angle dependence of the polarized light transmittance is small, and it can be arranged at a position where concentrated light is incident.

As described above, the light source device of the present invention separates the light from a plurality of semiconductor lasers by the dichroic mirror, and the green light and the red light that are excited and emitted by the separated light are arranged at the position where the converging light is incident. The blue light, which is the other light after polarization conversion by a small retardation plate, is efficiently condensed and synthesized to obtain white light, so that a small, efficient, and inexpensive light source device can be constructed.

(Embodiment 2)

4 is a configuration diagram of a light source device according to Embodiment 2 of the present invention.

The light source device 72 of Embodiment 2 includes: a semiconductor laser 51, a heat sink 52, a condenser lens 53, a heat sink 54, a condenser lens 56, 59, a reflection mirror 57, and a half-wave plate as a first retardation plate. 58. The first diffuser plate 60, dichroic mirror 61, condensing lenses 62, 63 as the first condensing element, fluorescent plate 67, condensing lens 68 as the second condensing element, the second diffuser 69, as The quarter-wave plate 70 and the reflection plate 71 of the second retardation plate. The state of each light beam 55 emitted from the solid-state light source and the polarization direction of the light entering and exiting the dichroic mirror 61 are shown in the figure. The phosphor plate 67 is composed of an aluminum substrate 65 on which a reflective film and a phosphor layer 64 are formed, and a motor 66 .

The same structure as the light source device 40 of Embodiment 1 of the present invention is a semiconductor laser 51, a radiator plate 52, a condenser lens 53, a radiator fin 54, a first diffuser plate 60, condenser lenses 62, 63, a fluorescent plate 67, a condenser An optical lens 68 , a second diffusion plate 69 , a quarter-wave plate 70 as a second retardation plate, and a reflection plate 71 .

Twenty-four (6×4) semiconductor lasers 51 and condenser lenses 53 arranged in a square shape are two-dimensionally arranged on the radiator plate 52 at constant intervals. The heat sink 54 is used to cool the semiconductor laser 51 . The semiconductor laser 51 emits blue light having a wavelength width of 447 nm to 462 nm, and emits linearly polarized light. In FIG. 4 , each semiconductor laser is arranged so that the polarized light emitted from the semiconductor laser 51 becomes P-polarized light on the incident surface of the dichroic mirror 61 without passing through the retardation plate. The light emitted from the plurality of semiconductor lasers 51 passes through the corresponding condensing lens 53 , and is respectively condensed and converted into parallel light beams 55 . The group of light beams 55 is condensed by a convex condensing lens 56 and reflected by a reflection mirror 57 . The reflected converging light is condensed, becomes divergent light, and enters the half-wave plate 58 as the first retardation plate. The incident angle of light to the half-wave plate 58 is 40 degrees or less. The half-wave plate 58 is a retardation plate with a phase difference of 1/2 wavelength in the vicinity of the emission center wavelength of the semiconductor laser 51 . In the half-wave plate 58 , when the P polarization direction in FIG. 4 is set to 0 degrees, the optical axis is arranged at 32.5 degrees. The half-wave plate 58 is provided with an adjustment mechanism for the rotation direction so that the arrangement angle of its optical axis can be adjusted.

The P-polarized light from the semiconductor laser 51 passes through the half-wave plate 58 to convert the polarization azimuth to 65 degrees, the light intensity of the P-polarized component becomes 18%, and the light intensity of the S-polarized component becomes 82%.

The half-wave plate 58 is a thin-film retardation plate utilizing birefringence by oblique vapor deposition of a dielectric material. Thin-film retardation plates are made of inorganic materials, and are as durable and reliable as inorganic optical crystals such as crystals. In addition, since thin-film wave plates are stacked with a film thickness sufficiently thinner than the wavelength of light, the change in phase difference with respect to the incident angle of light is very small compared to a phase plate of inorganic optical crystals such as crystal. Therefore, even when it is arranged at a position where converging or diverging light is incident, it is possible to efficiently perform rotational conversion of the P polarization azimuth from the semiconductor laser 51 . In addition, since the half-wave plate 58 is arranged at the position where the condensed light is incident, the size of the half-wave plate 58 can be reduced to 1/2 compared with the conventional arrangement at the position where the parallel light is incident. Below 2, the half-wave plate can greatly reduce the cost.

The light transmitted through the half-wave plate 58 is converted into approximately parallel light by the condensing lens 59 , enters the first diffuser plate 60 , is diffused, and enters the dichroic mirror 61 .

The spectral transmittance characteristic of the dichroic mirror 61 is shown in FIG. 5 . The dichroic mirror 61 has the following characteristics: the wavelength at which the transmittance is 50% is 465 nm when S polarized light is 442 nm when P polarized light, and makes blue light transmit and reflect, and has a wavelength of 96 nm for color light containing green and red components. % above to make it through. The S-polarized component of light incident on the dichroic mirror 61 is reflected, and the P-polarized component is transmitted. Since the optical axis of the half-wave plate 58 is arranged at 32.5 degrees, the polarization azimuth of the incident light is 65 degrees, and the light intensities of the S-polarization component and the P-polarization component are 82% and 18%, respectively.

The S-polarized light reflected by the dichroic mirror 61 is condensed by the condensing lenses 62 and 63, superimposed into spot lights with a diameter of 1.5 mm to 2.5 mm whose light intensity is 13.5% of the peak intensity, and enters the fluorescent light. Plate 67. The first diffuser plate 60 diffuses the light so that the diameter of the spot light becomes a desired diameter. The phosphor plate 67 is a controllable circular substrate including an aluminum substrate 65 on which a reflective film and a phosphor layer 64 are formed, and a motor 66 at the center. The reflective film of the phosphor plate 67 is a metal film or a dielectric film that reflects visible light, and is formed on an aluminum substrate. Furthermore, the phosphor layer 64 is formed on the reflective film. A Ce-activated YAG-based yellow phosphor that is excited by blue light and emits yellow light including green and red components is formed in the phosphor layer 64 . A representative chemical structure of the crystal matrix of the phosphor is Y ₃ Al ₅ O ₁₂ . Phosphor layer 64 is formed in an annular shape.

Phosphor layer 64 excited by spot light emits yellow light including light of green and red components. The phosphor plate 67 is an aluminum substrate, and by rotating the phosphor plate 67 , the temperature rise of the phosphor layer 64 caused by the excitation light can be suppressed, and the phosphor conversion efficiency can be stably maintained. The light incident on the phosphor layer 64 fluoresces green and red color light components and is emitted from the phosphor plate 67 . In addition, the light emitted toward the reflective film side is reflected by the reflective film and emitted from the fluorescent plate 67 . The green light and red light emitted from the fluorescent plate 67 become natural light, which is again condensed by the condensing lenses 62 and 63 , converted into approximately parallel light, and then transmitted through the dichroic mirror 61 .

On the other hand, 18% of the P-polarized blue light transmitted through the dichroic mirror 61 enters the condenser lens 68 as the second condenser element, and is condensed. The focal length of the condensing lens 68 is such that the condensing angle is 40 degrees or less, and a condensing point is formed in the vicinity of the reflection plate 71 . The condensed light condensed by the condensing lens 68 enters the second diffuser plate 69 . The second diffuser plate 69 diffuses incident light, uniformizes the light intensity distribution, and eliminates speckle of laser light. The second diffusion plate 69 has a diffusion surface formed of fine concavo-convex shapes on the glass surface of the thin plate. The second diffuser 69 is a diffuser in which the primary transmitted light on the diffuser surface has a diffusion angle of approximately 4 degrees and maintains polarization characteristics.

The light transmitted through the second diffuser 69 enters the quarter-wave plate 70 as the second retardation plate. The quarter-wave plate 70 is a retardation plate with a phase difference of 1/4 wavelength near the emission center wavelength of the semiconductor laser 51 . When the P polarization direction in FIG. 4 is set to 0 degrees, the quarter wave plate 70 arranges the optical axis at 45 degrees. The quarter-wave plate 70 is a thin-film retardation plate utilizing birefringence by oblique vapor deposition of a dielectric material. Thin-film retardation plates are made of inorganic materials, and are as durable and reliable as inorganic optical crystals such as crystals.

The light transmitted through the quarter-wave plate 70 and converted into circularly polarized light is phase-inverted by the reflector 71 formed with a reflective film such as aluminum or a dielectric multilayer film, and becomes divergent light as reversed circularly polarized light. After passing through the quarter-wave plate 70, it is converted into S polarized light. Furthermore, since no member disturbing the polarized light is arranged between the quarter-wave plate 70 and the reflecting plate 71, it is possible to efficiently convert the P-polarized light into the S-polarized light.

The S-polarized light converted by the quarter-wave plate 70 is diffused again by the second diffuser 69 , converted into parallel light by the condenser lens 68 , and reflected by the dichroic mirror 61 .

In this way, the fluorescent light from the fluorescent plate 67 and the efficiently polarized blue light are synthesized by the dichroic mirror 61 and emitted as white light. A light emission characteristic with a good white balance can be obtained by fluorescently emitting yellow light including green and red components and blue light from the semiconductor laser 51 . Even if this emission spectrum characteristic is separated into three primary color lights of blue, green, and red by the optical system of the projection display device, monochromatic light with desired chromaticity coordinates can be obtained.

In Embodiment 1 of the present invention, the separation ratio of blue light is determined by the transmittance characteristics of the dichroic mirror 29 in the blue wavelength range, and the separation ratio varies slightly. On the other hand, in Embodiment 2 of the present invention, since the half-wave plate 58 capable of adjusting the arrangement angle of the optical axis is used to control the separation ratio of the blue light transmitted and reflected by the dichroic mirror 61, The deviation of the separation ratio is very small. Therefore, the deviation of the white balance characteristic becomes very small.

The half-wave plate 58 has been described using a thin-film retardation plate, but a fine-structured retardation plate utilizing birefringence caused by a fine periodic structure equal to or less than the wavelength of light may also be used.

In Embodiment 2, the half-wave plate 58 is used as the first retardation plate, but it is also possible to use a quarter-wave plate as the first retardation plate and arrange it so as to emit light from the semiconductor laser 51. The polarized light becomes S-polarized light, and the arrangement angle of the optical axis is adjusted so that the S-polarized component and the P-polarized component of the transmitted blue light have a predetermined ratio.

In addition, in Embodiment 2, as shown in FIG. 4 , the structure in which the half-wave plate 58 is arranged at the position where the divergent light enters is described, but the half-wave plate 58 may also be arranged at the position where the convergent light enters. The location of the incident. For example, the half-wave plate 58 may be arranged in front of the converged light reflected by the mirror 57 to condense it.

As described above, the light source device of the present invention polarizes light from a plurality of semiconductor lasers at a constant ratio through a small half-wave plate and a dichroic mirror arranged at a position where converging light or diverging light is incident, and The yellow light including green and red and the other blue light, which are separated by polarization, are efficiently condensed and combined to obtain white light. Therefore, it is possible to form a small, high-efficiency And cheap light source device.

(Embodiment 3)

6 is a diagram showing a configuration of a first projection display device according to Embodiment 3 of the present invention. As an image forming element, a transmissive liquid crystal panel of an active matrix type in which a thin film transistor is formed in a pixel region in a TN mode or a VA mode is used.

Light source device 40 comprises: blue semiconductor laser device 21, radiator plate 22, condenser lens 23, radiator fin 24, lens 26,27, the first diffusion plate 28, dichroic mirror 29, condenser lens 30,31, are formed by Fluorescent plate 35, condenser lens 36, second diffusion plate 37, quarter-wave plate 38, reflective plate 39 constituted by reflective film and aluminum substrate 33 of phosphor layer 32 and motor 34. Since the above is the light source device 40 according to Embodiment 1 of the present invention, repeated description thereof will be omitted.

The projection display device 80 according to Embodiment 3 further includes: a first lens array plate 200, a second lens array plate 201, a polarization conversion element 202, an overlapping lens 203, a blue reflective dichroic mirror 204, a green reflective dichroic mirror 205, 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, exiting side polarizing plates 220, 221, 222 , a color synthesis prism 223 composed of a red reflective dichroic mirror and a blue reflective dichroic mirror, and a projection lens 224 .

The white light from the light source device 40 enters 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 many light beams. The split 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 opening shapes similar to those of the liquid crystal panels 217 , 218 , and 219 . The focal length of the lens elements of the second lens array plate 201 is determined such that the first lens array plate 200 and the liquid crystal panels 217 , 218 , and 219 are in 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 is composed of a polarization separation prism and a half-wave plate, and converts the natural light from the light source into light of one polarization direction. Since fluorescent light is natural light, it is polarized into one polarization direction, and blue light is incident as S-polarized light, and is emitted as S-polarized light without undergoing polarization conversion.

The light from the polarization conversion element 202 enters the superposition lens 203 . The superimposing lens 203 is a lens for superimposing and illuminating the liquid crystal panels 217 , 218 , and 219 with light emitted from each lens element of the second lens array plate 201 . The first lens array plate 200, the second lens array plate 201, the polarization conversion element 202, and the superposition lens 203 are used as an illumination optical system.

The light from the superposition lens 203 passes through the blue reflecting dichroic mirror 204 and the green reflecting dichroic mirror 205 as color separation elements, and is separated into blue light, green light, and red light. The green light passes through the field lens 211 and the incident-side polarizing plate 214 , and enters the liquid crystal panel 217 . The blue light is reflected by the reflecting mirror 206 , passes through the field lens 212 and the incident-side polarizing plate 215 , and enters the liquid crystal panel 218 . The red light passes through the relay lenses 209 and 210 and the reflection mirrors 207 and 208 to be refracted and reflected, 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 are arranged on both sides of each liquid crystal panel 217, 218, and 219 as Combinations of incident-side polarizers 214, 215, and 216 and exit-side polarizers 220, 221, and 222 whose transmission axes are perpendicular to each other modulate light to form green, blue, and red images. The light of each color passing through the polarizing plates 220, 221, and 222 on the exit side passes through the color synthesis prism 223, and the light of each color of red and blue is respectively reflected by the red reflective dichroic mirror and the blue reflective dichroic mirror, and synthesized into green light, which is incident on the projection lens 224. The light incident on the projection lens 224 is enlarged and transmitted to a screen (not shown).

The light source device is composed of a plurality of solid light sources in a small size, and efficiently emits white light with a good white balance, so that a long-life and high-brightness projection display device can be realized. In addition, since three liquid crystal panels using polarized light instead of a time-division system are used for the image forming element, a bright and high-definition projected image can be obtained with good color reproduction without color break. In addition, since the total reflection prism is unnecessary compared with the case where three DMD elements are used, the prism for color synthesis is a small prism with 45-degree incidence, so the projection display device can be configured in a smaller size.

As described above, the first projection display device of the present invention uses a light source device that can convert P-polarized light from a semiconductor laser at a constant intensity ratio through a solid-state light source as a semiconductor laser and a dichroic mirror. Separation, the yellow light containing green and red components that is excited and emitted by one of the separated lights, and the blue light that is efficiently polarized by a small quarter-wave plate for the other separated light synthesized to obtain white light. Therefore, a small and inexpensive projection display device can be configured. As the light source device, the light source device 40 shown in FIG. 1 was used, but the light source device 72 shown in FIG. 4 may also be used. In this case, the variation in white balance of white light emitted from the light source device is very small, and an inexpensive light source device and projection display device can be configured.

A transmissive liquid crystal panel is used as an image forming element, but it may also be configured using a reflective liquid crystal panel. By using a reflective liquid crystal panel, it is possible to configure a smaller and higher-definition projection display device.

(Embodiment 4)

FIG. 7 is a second projection display device according to Embodiment 4 of the present invention. The second projection display device 90 uses three DMDs as image forming elements.

Light source device 40 comprises: blue semiconductor laser device 21, radiator plate 22, condenser lens 23, radiator fin 24, lens 26,27, the first diffusion plate 28, dichroic mirror 29, condenser lens 30,31, are formed by Fluorescent plate 35, condenser lens 36, second diffuser 37, quarter-wave plate 38, and reflective plate 39 constituted by reflective film and phosphor layer 32 of aluminum substrate 33 and motor 34. The above is the light source device 40 according to Embodiment 1 of the present invention.

The white light emitted from the light source device 40 enters the condensing lens 100 and is condensed on a rod 101 . The incident light to the rod 101 is reflected multiple times inside the rod, so that the light intensity distribution is made uniform and emitted. The light emitted from the rod 101 is condensed by the relay lens 102 , reflected by the reflection mirror 103 , passes through the field lens 104 , and enters the total reflection prism 105 . Here, the condenser lens 100, the rod 101, the relay lens 102, the reflection mirror 103, and the field lens 104 are an example of an illumination optical system.

The total reflection prism 105 is composed of two prisms, and a thin air layer 106 is formed on surfaces close to each other. The air layer 106 totally reflects light incident at an angle equal to or 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 reflective dichroic mirror 108 and a red reflective dichroic mirror 109 are formed on adjacent surfaces of the respective prisms. Passing through the blue reflection dichroic mirror 108 and the red reflection dichroic mirror 109 of the color prism 107, it is separated into blue light, red light, and green light, and enters the DMDs 110, 111, and 112, respectively. The DMDs 110 , 111 , and 112 deflect the micromirrors according to video signals, and reflect light entering the projection lens 113 and light traveling outside the effective area of the projection lens 113 . The light reflected by DMD110, 111, 112 passes through color prism 107 again. In the process of passing through the color prism 107 , the separated blue, red, and green colored lights are synthesized and enter the total reflection prism 105 .

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

The light source device is composed of a plurality of solid-state light sources and efficiently emits white light with a good white balance, so that a long-life and high-brightness projection display device can be realized. In addition, since the DMD is used for the image forming element, it is possible to constitute a projection display device having higher light resistance and heat resistance than an image forming element using liquid crystal. Furthermore, since three DMDs are used, it is possible to obtain a bright and high-definition projected image with excellent color reproduction.

As described above, the second projection display device of the present invention uses a light source device capable of converting P-polarized light from a semiconductor laser at a constant intensity ratio through a solid-state light source as a semiconductor laser and a dichroic mirror. Separation, the yellow light containing green and red components that is excited and emitted by one of the separated lights, and the blue light that is efficiently polarized by a small quarter-wave plate for the other separated light synthesized to obtain white light. Therefore, a small and inexpensive projection display device can be configured. As the light source device, the light source device 40 shown in FIG. 1 was used, but the light source device 72 shown in FIG. 4 may also be used. In this case, the variation in white balance of white light emitted from the light source device is very small, and an inexpensive light source device and projection display device can be configured.

As described above, Embodiments 1 to 4 have been described as examples of the technology disclosed in this application. However, the technology in the present invention is not limited thereto, and can be applied to embodiments with changes, substitutions, additions, omissions, and the like.

The present invention can be applied to a light source device of a projection display device using an image forming element.

Claims (16)

1. A light source device, comprising: solid light source; a light concentrating element that condenses the light from the solid light source; a retardation plate that converts linearly polarized light into circularly polarized light; and Reflective plate, The retardation plate is disposed between the light concentrating element and the reflective plate at a position where convergent light and divergent light are incident. 2. The light source device according to claim 1, wherein the retardation plate is a quarter-wave plate. 3. A light source device, comprising: solid light source; a retardation plate, which converts the polarization orientation of light from said solid light source, and controls the light of P polarization and S polarization components to a certain ratio; and a dichroic mirror that polarizes light from the retardation plate, The phase difference plate is arranged between the solid light source and the dichroic mirror at a position where converging light or diverging light is incident. 4. The light source device according to claim 3, wherein the retardation plate is a half-wave plate or a quarter-wave plate. 5. The light source device according to claim 1 or 3, wherein the phase difference plate is arranged at a position where an incident light angle becomes 40 degrees or less. 6. The light source device according to claim 1 or 3, wherein the phase difference plate is a thin-film phase difference plate using birefringence based on oblique evaporation, or a microstructured phase plate using birefringence based on microstructures. bad board. 7. A light source device, comprising: solid light source; The first retardation plate, which transforms the polarization orientation of the light from the solid light source, and controls the light of P polarization and S polarization components to a certain ratio; a dichroic mirror, which performs polarization separation on the light from the first retardation plate; a condensing element that condenses the light from the dichroic mirror; a second retardation plate that converts linearly polarized light into circularly polarized light; and Reflective plate, The first retardation plate is disposed between the solid light source and the dichroic mirror at a position where converging light or divergent light is incident, The second retardation plate is arranged between the light converging element and the reflecting plate at a position where convergent light and divergent light are incident. 8. The light source device according to claim 7, wherein the first retardation plate is a half-wave plate or a quarter-wave plate. 9. The light source device according to claim 7, wherein the second retardation plate is a quarter-wave plate. 10. The light source device according to claim 7, wherein at least one of the first phase difference plate and the second phase difference plate is arranged at a position where an incident light angle becomes 40 degrees or less. 11. The light source device according to claim 7, at least one of the first phase difference plate and the second phase difference plate is a film phase difference plate using birefringence based on oblique evaporation or using Microstructured retardation plate based on microstructured birefringence. 12. The light source device according to claim 1, 3 or 7, wherein the solid-state light source is a blue semiconductor laser. 13. The light source device according to claim 1, 3 or 7, wherein the light emitted from the solid light source is linearly polarized light. 14. A projection display device comprising: light source; an illumination optical system that condenses light from the light source and illuminates an illuminated area; an image forming element that forms an image based on the image signal; and a projection lens that magnifies and projects an image formed by the image forming element, The light source is the light source device described in claim 1, 3 or 7. 15. The projection display device according to claim 14, wherein the image forming element is a liquid crystal panel. 16. The projection display device according to claim 14, wherein the image forming element is a digital micromirror device (DMD) of a mirror deflection type.