JP2012159603A - Light source device and projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light source device including a color wheel in an optical system, which prevents deterioration of reliability and realizes high luminance.SOLUTION: Projection shape adjustment means 24 arranged between a blue light source and a color wheel 20 adjusts a projection shape of blue light (B), which is emitted from a blue light source 1 and is delivered to a phosphor layer 22 of the color wheel 20, so that a projection range in a radial direction becomes wider than that in a circumferential direction at the color wheel 20. Since an annular range where the blue light (B) is projected also disperses in a radial direction and a heat generating range is also dispersed in a radial direction while the color wheel 20 is driven in a rotating manner, heat conduction becomes excellent. As a result, a decrease in wavelength conversion efficiency of the blue light (B) from the blue light source is avoided at the phosphor layer 22. And, a thermal load on a binder constituting the phosphor layer 22 is reduced, and a deterioration of the color wheel 20 is prevented by avoiding an alteration (blackening) of the binder.

Description

  The present invention relates to a light source device for a projector that obtains a large-screen display image by enlarging and projecting a display image using a projection optical system, and a projector using the same.

  Projectors (irradiation type image display devices) that are used in home theaters, presentations, and the like to enlarge and project a display image using a projection optical system to obtain a large screen display image have been commercialized. Some projectors display an image on a screen via an electro-optical device using a spatial light modulator such as a digital micromirror device or a liquid crystal display element using light emitted from a light source as illumination light. . Some projectors use a high-pressure mercury lamp or a xenon lamp as a light source, but they are not preferable because of mercury content and heat generation. Therefore, in recent years, a projector using a light emitting diode (LED) or a laser has been devised.

  The present inventors have also developed a so-called “hybrid type” projector using an LED and a laser as a light source. Such a hybrid projector uses, for example, an LED as a red light source, a blue laser as a blue light source, and a phase and wavelength converted from a blue laser as a green light source. In such a projector, a color wheel that rotates at high speed is generally used as a time-division filter element (for example, Japanese Patent Application No. 2010-0387748).

  An example of the color composition method of the hybrid projector is schematically shown in FIG. In FIG. 3, a projector 100 includes, as components of an irradiation optical system, a blue light source 1, a red light source 2, a color wheel 5, dichroic mirrors 3, 8, lenses 4, 9, mirrors 6, 7, and a spatial light modulator. A digital micromirror device 10, a projection optical system 11, and a screen 12 are provided. Blue light (B) emitted from a blue light source 1 using a blue laser emitter passes through a dichroic mirror 3 and a lens 4 that transmit blue light, and is applied to a color wheel 5. The color wheel 5 is a disk made of metal or glass, and a phosphor layer in which a phosphor emitting green light (G) is mixed in a binder such as a resin is circumferentially provided on the surface of the substrate. More specifically, in a range of a predetermined central angle along the circumferential direction (see reference sign θ in FIG. 2), a certain width with respect to the radial direction of the color wheel 5 is provided. Is provided. Accordingly, the blue light that has passed through the portion of the color wheel 5 where the phosphor layer is not provided passes through the dichroic mirror 8, is condensed by the lens 9, reaches the digital micromirror device 10, and is reflected from the color wheel 5. Some of the blue light returns to the blue light source 1 side.

On the other hand, when blue light is irradiated from the blue light source 1 onto the phosphor layer, green light is emitted, and this green light is reflected by the dichroic mirror 3 that reflects the green light through the lens 4, and further, mirror 6, 7 and reflected by the dichroic mirror 8 and collected by the lens 9 to reach the digital micromirror device 10.
The red light (R) from the red light source 2 using the red LED passes through the dichroic mirror 3, is reflected by the mirrors 6 and 7, is reflected by the dichroic mirror 8, is condensed by the lens 9, and is digitally converted. The micromirror device 10 is reached.
The three primary colors of blue light (B), green light (G), and red light (R) incident on the digital micromirror device 10 are processed in time series as images of the respective colors by synchronizing the switching of the incident light. Then, an image is projected onto the screen 12 via the projection optical system 11. Since the rotation control of the color wheel 5 and the light control in the digital micromirror device 10 and the projection optical system 11 are well-known techniques, the description thereof is omitted.

  As described above, in the projector 100 illustrated in FIG. 3, blue light (B) is emitted from the blue light source 1 and red light (R) is emitted from the red light source 2. The green light is obtained by converting the wavelength of the blue light from the blue light source 1 by the phosphor layer of the color wheel 5 (see, for example, Patent Documents 1 and 2). Therefore, in the following description, a light source that emits monochromatic light like the blue light source 1 is also referred to as “excitation light source”, and blue light (B) is also referred to as “excitation light”.

JP 2009-277516 A JP 2008-52070 A

By the way, the optical system of the projector 100 illustrated in FIG. 3 is configured such that the blue light (B) emitted from the blue light source 1 is converged and irradiated on one point on the annular surface of the color wheel 5. Therefore, although the color wheel 5 is rotationally driven at a high speed, an annular range having a specific radius on which the blue light (B) is projected generates heat intensively. Conversion efficiency will decrease. As a result, there is a problem that the display image becomes dark. Further, the binder constituting the phosphor layer is altered (blackened) in an annular range with a specific radius on which blue light (B) is projected, and the reliability (quality) of the color wheel 5, and thus the light source device and the same As a result, the reliability of the projector 100 using the above-mentioned technology is lowered.
On the other hand, when the laser output of the blue light source 1 is increased in order to improve the brightness of the display image, there is a drawback that the above problem is promoted.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to prevent a decrease in reliability of a light source device including a color wheel in an optical system and to achieve high brightness. It is in. Another object of the present invention is to prevent a decrease in reliability of a projector using the light source device and to achieve high brightness.

(Aspect of the Invention)
The following aspects of the present invention exemplify the configuration of the present invention, and will be described separately for easy understanding of various configurations of the present invention. Each section does not limit the technical scope of the present invention, and some of the components of each section are replaced, deleted, or further while referring to the best mode for carrying out the invention. Those to which the above components are added can also be included in the technical scope of the present invention.

(1) A light source device for a projector, comprising: an excitation light source that emits monochromatic light; and a phosphor layer that receives excitation light emitted from the excitation light source in a range of a predetermined central angle along a circumferential direction. The projected shape of the excitation light that is disposed between the formed color wheel and the excitation light source and the color wheel and is irradiated from the excitation light source to the phosphor layer of the color wheel is a circumferential direction in the color wheel. And a projection shape adjusting means for adjusting the projection range in the radial direction to be wider than that of the light source device (claim 1).
In the light source device according to this aspect, the projection shape of the excitation light emitted from the excitation light source and applied to the phosphor layer of the color wheel is projected by the projection shape adjusting unit disposed between the excitation light source and the color wheel. The range in which the excitation light is projected onto the phosphor layer of the color wheel is dispersed in the radial direction by adjusting the projection range in the radial direction to be wider than the circumferential direction in the color wheel. As a result, in a state where the color wheel is driven to rotate, the annular area where the excitation light is projected is also dispersed in the radial direction, the heat generation range is also dispersed in the radial direction, and the heat dissipation is good. A decrease in the wavelength conversion efficiency of the excitation light from the excitation light source is avoided. Further, the thermal load of the binder constituting the phosphor layer is reduced, and the color wheel is prevented from being deteriorated.

(2) In the above item (1), the projection shape of the excitation light that is adjusted by the projection shape adjusting means and is applied to the phosphor layer of the color wheel is a multibeam form in the radial direction of the color wheel A light source device (claim 2).
In the light source device described in this section, the projection shape of the excitation light that is adjusted by the projection shape adjusting unit and is applied to the phosphor layer of the color wheel has a form in which multiple beams are formed in the radial direction of the color wheel. The range in which the excitation light is projected onto the phosphor layer of the color wheel is dispersed in a multipoint manner in the radial direction. As a result, when the color wheel is driven to rotate, the annular area in which the excitation light is projected is also dispersed in a plurality of concentric bands, and the heat generation area is also dispersed in the radial direction, resulting in good heat dissipation and fluorescence. A decrease in the wavelength conversion efficiency of the excitation light from the excitation light source in the body is avoided. Further, the thermal load of the binder constituting the phosphor layer is reduced, and the color wheel is prevented from being deteriorated.

(3) In the above items (1) and (2), the projection shape adjusting means is a light source device comprising a diffraction grating (claim 3).
The light source device described in this section compares the projected shape of the excitation light emitted from the excitation light source and irradiated on the phosphor layer of the color wheel by the diffraction action of monochromatic light by the diffraction grating in the circumferential direction of the color wheel. Thus, the radial projection range is adjusted to be wide. If the diffraction action (diffraction angle) by the diffraction grating is sufficiently obtained, the projection shape of the excitation light adjusted by the projection shape adjusting means and applied to the phosphor layer of the color wheel is in the radial direction of the color wheel. A multi-beam mode is obtained. On the other hand, when the diffractive action by the diffraction grating is small, the projected shape becomes a form that spreads continuously in the radial direction of the color wheel without being clearly multi-beamed. However, in any case, the range in which the excitation light is projected onto the phosphor layer of the color wheel is dispersed in the radial direction, and the excitation light is projected in a state where the color wheel is rotationally driven. The annular range is also dispersed in the radial direction, and the heat generation range is also dispersed in the radial direction, so that the heat absorption is good, and a decrease in the wavelength conversion efficiency of the excitation light from the excitation light source in the phosphor is avoided. . Further, the thermal load of the binder constituting the phosphor layer is reduced, and the color wheel is prevented from being deteriorated.

(4) In the above items (1) and (2), the projection shape adjusting means is a light source device configured by a cylindrical lens.
In the light source device described in this section, the projection shape of the excitation light emitted from the excitation light source and irradiated on the phosphor layer of the color wheel is compared with the circumferential direction of the color wheel by a unidirectional diffraction action by the cylindrical lens. Thus, the radial projection range is adjusted to be wide. Accordingly, the projection shape of the excitation light adjusted by the projection shape adjusting means and applied to the phosphor layer of the color wheel becomes an aspect that extends in an elliptical shape or an oval shape in the radial direction of the color wheel, and the phosphor of the color wheel The range in which the excitation light is projected onto the layer is dispersed in the radial direction. As a result, in a state where the color wheel is driven to rotate, the annular area where the excitation light is projected is also dispersed in the radial direction, the heat generation range is also dispersed in the radial direction, and the heat dissipation is good. A decrease in the wavelength conversion efficiency of the excitation light from the excitation light source is avoided. Further, the thermal load of the binder constituting the phosphor layer is reduced, and the color wheel is prevented from being deteriorated.

(5) The light source device according to (1) to (3), wherein a condenser lens is disposed between the projection shape adjusting unit and the color wheel.
In the light source device described in this section, the focal length of the excitation light is appropriately adjusted by the condensing lens arranged between the projection shape adjusting means and the color wheel.
(6) The light source device as set forth in (5), wherein the condenser lens is a cylindrical lens.
In the light source device described in this section, the focal length of the excitation light is appropriately adjusted by the condensing lens arranged between the projection shape adjusting means and the color wheel. In addition, since the condensing lens is a cylindrical lens, the projected shape of the excitation light applied to the phosphor layer of the color wheel is further emphasized and adjusted by the projected shape adjusting means.

(7) In the above items (1) to (6), the phosphor layer is formed at least in the radial position of the color wheel corresponding to the projected shape of the excitation light irradiated (Claim 4).
In the light source device described in this section, the phosphor layer has a projected shape of the irradiated excitation light, which is a range used for wavelength conversion of excitation light from the excitation light source, in the entire radial range of the color wheel. By providing at the corresponding radial position, the effects described in (1) to (5) above are obtained. In addition, in the entire range in the radial direction of the color wheel, the usage amount of the range other than the range used for the wavelength conversion of the excitation light from the excitation light source is reduced by not installing the phosphor layer.

(8) It is possible to constitute a projector including the light source device according to the above items (1) to (7).
The projector described in this section exhibits the operations described in the above items (1) to (6) in the light source device that is a component thereof.

  Since the present invention is configured as described above, it is possible to prevent a decrease in reliability of the light source device including a color wheel in the optical system and to achieve high luminance. In addition, it is possible to prevent a decrease in reliability of the projector using the light source device and achieve high brightness.

It is a schematic diagram which shows the principal part of the light source device based on embodiment of this invention. FIG. 2 is a diagram illustrating a configuration aspect of an optical system of the light source device illustrated in FIG. 1, in which (a) is a schematic diagram illustrating a transmission type, and (b) is a reflection type. It is a schematic diagram of a conventional hybrid projector.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Here, parts that are the same as or correspond to those in the prior art are denoted by the same reference numerals, and detailed description thereof is omitted. The light source device according to the embodiment of the invention can be applied to a hybrid projector as illustrated in FIG. Therefore, with respect to the overall configuration of the light source device, the projector FIG. 3 in FIG. 3 is referred to as appropriate, and the same applies to the projector using the light source device.

  FIG. 1 shows a main part of a light source device according to an embodiment of the present invention. In the present light source device, a projection shape adjusting means 24 is arranged between a blue light source 1 that is an excitation light source and a color wheel 20. This projection shape adjusting means 24 has a diameter of the projection shape of blue light (B) as excitation light irradiated from the blue light source 1 to the phosphor layer 22 of the color wheel 20 as compared to the circumferential direction of the color wheel 20. Adjustment is made so that the projection range of the direction becomes wide. In the example shown in the figure, a diffraction grating is used for the projection shape adjusting means 24, so that the blue light (b) projected by the projection shape adjusting means 24 and applied to the phosphor layer 22 of the color wheel 20 is projected. The shape is such that multiple beams are formed in the radial direction of the color wheel 20 and three points (BA, BB, BC) are irradiated to different radial positions.

In addition, in the example shown in the figure, the multi-beam irradiation with the diffraction grating constituting the projection shape adjusting means 24 is a mode in which three points are irradiated to different radial positions.
When the diffraction action (diffraction angle) by the diffraction grating is sufficiently obtained, the projected shape of the blue light (B) that is adjusted by the projected shape adjusting means 24 and is applied to the phosphor layer 22 of the color wheel 20 is: As shown in FIG. 1, the color wheel 20 is multibeamed in the radial direction. On the other hand, when the diffractive action by the diffraction grating is small, the projected shape is spread in the radial direction of the color wheel 20 without clearly forming multiple beams.

On the other hand, the color wheel 20 is obtained by forming a phosphor layer 22 on the surface of a substrate (color wheel substrate) 202, and this phosphor layer 22 corresponds to the projected shape of the irradiated blue light (B). The color wheel 20 is formed at a radial position. In the example of FIG. 1, the phosphor layer 22A is concentrically formed so as to correspond to the projected shape of the blue light (b) that is multi-beamed in the radial direction of the color wheel 20 and is irradiated at three points to different radial positions. , 22B, 22C are formed.
The phosphor layer 22 is obtained by dispersing a phosphor in a binder. As a specific example, a silicone resin is used for the binder, and garnet is used for the phosphor. In addition, a specific method for forming the phosphor layer 22 on the color wheel substrate 202 can be selected as appropriate. For example, it can be formed by screen printing.

For reference, the color wheel substrate 202 constituting the color wheel 5 is made of metal or glass as described in the related art.
In addition to the garnet, the following materials are used as the phosphor material of the phosphor layer 22. For example, phosphors for green light emission include Zn ₂ SiO ₄ : Mn, BaAl ₁₂ O ₁₉ : Mn, BaMgAl ₁₄ O ₂₃ : Mn, SrAl ₁₂ O ₁₉ : Mn, ZnAl ₁₂ O ₁₉ : Mn, CaAl ₁₂ O ₁₉ : Mn YBO ₃ : Tb, LuBO ₃ : Tb, GdBO ₃ : Tb, ScBO ₃ : Tb, Sr ₄ Si ₃ O ₈ Cl ₄ : Eu, and the like. Further, for example, as the red-emitting _{phosphor, Y 2 O 3: Eu,} Y 2 SiO 5: Eu, Y 3 Al 5 O 12: Eu, Zn 3 (P0 4) 2: Mn, YBO 3: Eu, ( Y, Gd) BO ₃ : Eu, GdBO ₃ : Eu, ScBO ₃ : Eu, LuBO ₃ : Eu, and the like.

  FIG. 2 illustrates the configuration of the optical system of the light source device according to the embodiment of the invention. FIG. 2A shows a transmissive light source device. The blue light (B) divided into three by the projection shape adjusting means 24 has its focal length adjusted by a condenser lens (see reference numeral 4 in FIG. 3). The color wheel 20 is irradiated. The blue light (B) transmitted through the color wheel 20 and the green light (G) obtained by wavelength conversion by the phosphor layer 22 are on the side opposite to the projection shape adjusting means 24 with respect to the color wheel 20. Each light enters the arranged light pipe 26, becomes uniform light in the light pipe 26, and is emitted from the tip surface of the light pipe 26. As illustrated in FIG. 3, the blue light (B) emitted from the light pipe 26 passes through the dichroic mirror 8 and is collected by the lens 9 to reach the digital micromirror device 10. In this case, the green light (G) also follows the same optical path as the blue light (B).

  On the other hand, FIG.2 (b) is a schematic diagram which shows a reflection type. In this case, the blue light (B) divided into three parts by the projection shape adjusting means 24 is transmitted through the dichroic mirror 3, and then the focal length is adjusted by the condenser lens (see reference numeral 4 in FIG. 3). The wheel 20 is irradiated. Then, the blue light (B) transmitted through the color wheel 20 is incident on a light pipe 26 disposed on the opposite side of the projection shape adjusting means 24 with respect to the color wheel 20 and becomes uniform light in the light pipe 26. Then, the light is emitted from the tip surface of the light pipe 26. Further, the green light (G) that has been wavelength-converted by the phosphor layer 22 and reflected by the color wheel 20 is refracted by the dichroic mirror 3 in a right-angle direction as shown in FIG. Incident light becomes uniform light in the light pipe 28 and is emitted from the front end surface of the light pipe 28. As illustrated in FIG. 3, the green light (G) emitted from the light pipe 28 is reflected by the mirrors 6 and 7, reflected by the dichroic mirror 8, collected by the lens 9, and collected by the digital micromirror. Device 10 is reached.

In addition, about the light pipes 26 and 28 used here, the well-known thing which repeats reflection of light inside may be used.
Although not shown, a cylindrical lens may be used instead of the diffraction grating constituting the projection shape adjusting means 24. In this case, similarly to the case where the diffraction action by the diffraction grating is small, the projected shape of the blue light (B) adjusted by the projected shape adjusting means 24 and applied to the phosphor layer 22 of the color wheel 20 is a multi-beam. It becomes an aspect which spreads in the radial direction of the color wheel 20 in the ellipse shape or the ellipse shape.

Now, according to the embodiment of the present invention configured as described above, the following operational effects can be obtained. First, blue light (B) emitted from the blue light source 1 and irradiated on the phosphor layer 22 of the color wheel 20 by the projection shape adjusting means 24 disposed between the blue light source 1 (FIG. 3) and the color wheel 20. Is adjusted so that the projection range in the radial direction is wider than the circumferential direction of the color wheel 20, so that the blue light (B) is projected onto the phosphor layer 22 of the color wheel 20. Will be dispersed in the radial direction of the color wheel 20. As a result, in a state in which the color wheel 20 is driven to rotate, the annular range in which the blue light (B) is projected is also dispersed in the radial direction, the heat generation range is also dispersed in the radial direction, and the heat sink is improved. A decrease in the wavelength conversion efficiency of the blue light (B) from the blue light source 1 in the phosphor layer 22 is avoided. Further, the thermal load of the binder constituting the phosphor layer 22 is reduced, and deterioration of the color wheel 20 can be prevented by avoiding the alteration (blackening) of the binder. And it becomes possible to raise the output of the blue light source 1, and it becomes possible to comprise a high-intensity light source device.
In addition, the projection shape adjustment by the projection shape adjusting means 24 can be performed by a diffraction grating or a cylindrical lens.

  Further, the projection shape of the blue light (B) adjusted by the projection shape adjusting means 24 and applied to the phosphor layer 22 of the color wheel 20 forms a multi-beam form in the radial direction of the color wheel 20. The range in which the blue light (B) is projected onto the phosphor layer 22 of the color wheel 20 is dispersed in a multipoint shape (BA, BB, BC) in the radial direction. As a result, in the state in which the color wheel 20 is driven to rotate, the annular area on which the blue light (B) is projected is also dispersed in a plurality of concentric belts, and the heat generation area is also dispersed in the radial direction, so that the phosphor A decrease in the wavelength conversion efficiency of the blue light (B) from the blue light source 1 in the layer 22 is avoided.

Furthermore, according to the embodiment of the present invention, the phosphor layer 22 of the color wheel 20 is used for wavelength conversion of the blue light (B) from the blue light source 1 in the entire radial range of the color wheel 20. By providing at a radial position corresponding to the projected shape of the emitted blue light (B), the above-described effects can be obtained. In addition, in this case, the phosphor layer 22 is not provided for the entire range in the radial direction of the color wheel 20 other than the range used for wavelength conversion of the blue light (B) from the blue light source 1. It is possible to reduce the manufacturing cost of the color wheel 20 by reducing the usage amount and reducing the usage amount of the relatively expensive phosphor.
In addition, a projector including the light source device according to the embodiment of the present invention exhibits the above-described effects in the light source device that is a component thereof.

  1: excitation light source, 20: color wheel, 22, 22A, 22B, 22C: phosphor layer, 24: projection shape adjusting means, B: excitation light

Claims (5)

A light source device for a projector,
An excitation light source that emits monochromatic light;
A color wheel formed with a phosphor layer that receives excitation light emitted from the excitation light source in a range of a predetermined central angle along the circumferential direction;
The projection shape of the excitation light that is disposed between the excitation light source and the color wheel and is irradiated from the excitation light source to the phosphor layer of the color wheel has a radial direction compared to a circumferential direction in the color wheel. A light source device comprising: a projection shape adjusting unit that adjusts so that a projection range is widened. 2. The projection shape of excitation light adjusted by the projection shape adjusting means and applied to the phosphor layer of the color wheel is in the form of multiple beams in the radial direction of the color wheel. The light source device described. The light source device according to claim 1, wherein the projection shape adjusting unit includes a diffraction grating. The said fluorescent substance layer is formed in the position of the radial direction of the said color wheel corresponding to the projection shape of the said excitation light irradiated at least, The any one of Claim 1 to 3 characterized by the above-mentioned. Light source device. A projector provided with the light source device of any one of Claim 1 to 4.

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