JP2008026853A - Light source device and image display apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light source capable of illuminating an object, such as a spatial optical modulation element, with higher illuminance without increasing a quantity of light emission per unit area of a light source and without decreasing the angle of a light emitted from the light source, by improving efficiency of use of light from the light source thereby improving E'tendue. <P>SOLUTION: The light source includes: a solid light emitting element 1 having a reflection film formed on the back thereof; first and second reflecting faces 2 and 3 disposed opposite to and parallel to each other and perpendicular to the surface of the solid light emitting element 1; and a third reflecting face 4 disposed perpendicular to the first and second reflecting faces 2 and 3 and inclined and opposite to the surface of the solid light emitting element 1. The reflecting film of the solid light emitting element 1 and the first to third reflecting faces 2, 3, and 4 form a closed polyhedron that has an emission opening 5 of an area smaller than the area of the light emitting face of the solid light emitting element 1. Light emitted from the solid light emitting element 1 is emitted outward from the emission opening 5. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a light source device that illuminates a spatial light modulation element in an image display device or the like, and an image display device that includes such a light source device.

  2. Description of the Related Art Conventionally, there has been proposed an image display apparatus that includes a spatial light modulation element, illuminates the spatial light modulation element with a light source device, and forms an image of modulated light that has passed through the spatial light modulation element. In such an image display device, the spatial light modulation element displays a display image and modulates illumination light in accordance with the image. The modulated light modulated by the spatial light modulator is imaged by an imaging optical system, and displays an image on a screen, for example.

  As such a light source device of an image display device, a light source device using a solid light emitting element as described in Patent Document 1 has been proposed. A solid light emitting element is a light emitting diode (LED), a semiconductor laser diode (LD), an electroluminescent element (EL), or the like.

  Further, as such a light source device of an image display device, one having an integrator optical system as shown in FIGS. 15 and 16 is used in order to uniformly illuminate the spatial light modulation element. This integrator optical system equalizes the luminance distribution of illumination light from a light source.

  In the fly-eye lens integrator optical system shown in FIG. 15, the luminance distribution of the illumination light that illuminates the spatial light modulator 103 is uniform by passing the illumination light through the fly-eye lenses 101 and 102 in which a plurality of small lenses are arranged. It becomes.

  In the rod integrator optical system shown in FIG. 16, when the illumination light passes through the prismatic rod 104, internal reflection in the rod 104 is repeated, and the luminance distribution of the illumination light is made uniform. That is, in this rod integrator optical system, a light source image is formed on one end face (incident end face) of the rod 104, or the light source 105 is brought into close contact, and the light from the light source 105 is internally reflected inside the rod 104 (total reflection). ) And is emitted from the other end surface (injection end surface) of the rod 104. By forming an image of the exit end face of the rod 104 on the spatial light modulation element 103 serving as an object to be illuminated, good illumination light having a uniform illumination distribution can be obtained.

JP 7-66455 A

  In the image display apparatus as described above, it is desired to display a high-luminance image by illuminating the spatial light modulation element with a higher luminance, and the output of the light source is increased. Yes. However, increasing the output of the light source increases power consumption, increases the amount of heat generation, and increases the size of the device configuration. Therefore, it is desired to illuminate the spatial light modulation element with high luminance.

By the way, as an optical theory, “Helmholtz-Lagrange invariant” is known that the following relationship always holds between two regions via an optical surface (for example, a lens).
Nuy = N′u′y ′ (∵N and N ′ are refractive indexes, u and u ′ are ray angles, and y and y ′ are image heights).

In addition, this relationship can be regarded as an etendue (E′tendue) when the image height (object height) y, y ′ is indicated as an area (S) and the light ray angles u, u ′ are indicated as solid angles (θ). In other words, it can be said that etendue is invariant in two regions through the optical surface. Etendue E is represented by the following equation.
E = πSsin ² θ

  This relationship does not change even in a plurality of optical systems, and also holds in the relationship between an object and an image. Therefore, this relationship is established between the illumination light source and the object to be illuminated (spatial light modulation element), and also in the light source device as described above.

  For example, in the rod integrator optical system using the prismatic rod 104 shown in FIG. 16, the radiation angle of the light beam from the exit end face of the rod 104 is the same as the radiation angle of the light beam from the light source 105. Lagrange's invariant "holds. In the optical system that forms an image of the exit end face of the rod 104, the “invariant of Helmholtz-Lagrange” is satisfied, so that “invariant of Helmholtz-Lagrange” is established for the entire illumination optical system.

Here, when the specifications of the illumination optical system (image height y ′ and light ray angle u ′) are sufficiently larger than the specifications of the light source (object height y and radiation angle u), the following relationship holds: This means that almost all of the emitted light can be taken into the illumination optical system.
Nuy <N'u'y '

  In the fly-eye integrator optical system, “Helmholtz-Lagrange invariant” is similarly established.

  Thus, the utilization efficiency of light from the light source in the light source device is determined by etendue, which is a function of the light emitting area and the light radiation angle in the light source. That is, the utilization efficiency of light from a surface light source having a finite size is uniquely determined by the light emitting area and radiation angle of the light source.

  Therefore, in order to illuminate an object to be illuminated such as a spatial light modulator with higher brightness, it is necessary to increase the amount of light emitted per unit area of the light source or to reduce the light emission angle from the light source. There will be. All of these measures are intended to improve the performance of the light source, and do not improve the utilization efficiency of light from the light source.

  In addition, as shown in FIGS. 17 and 18, an integrator optical system using a tapered rod or a tapered light pipe is proposed as an illumination optical system for improving the light utilization efficiency from the light source. Has been. As shown in FIG. 17, in the integrator optical system using the tapered light pipe whose exit opening is larger than that of the light source 105, the light exit angle θ 'Becomes smaller. On the contrary, as shown in FIG. 18, in the integrator optical system using the tapered light pipe whose exit opening is smaller than that of the light source 105, the “invariant of Helmholtz-Lagrange” is established. The injection angle θ ′ increases. In these integrator optical systems, etendue has not changed. That is, in these integrator optical systems, the light utilization efficiency of the light from the light source is not improved.

  Also, using an LED as a light source, light from the LED is introduced into the light pipe, unnecessary polarized light is returned to the LED in the light pipe, and return light (reflected light) from the LED is rotated 90 deg by the phase difference plate. A light source device has been proposed. This light source device has a configuration relating to polarization conversion, and performs polarization conversion while improving light utilization efficiency, that is, improving etendue. However, since it is assumed that polarization conversion is performed, the etendue cannot be improved to an arbitrary value.

  Therefore, the present invention is proposed in view of the above-described circumstances, and increases the light emission amount per unit area of the light source by improving the utilization efficiency of light from the light source and improving the etendue. There is also provided a light source device that can illuminate an object to be illuminated such as a spatial light modulation element with higher luminance without reducing the light emission angle from the light source, and an image using such a light source device. The object is to provide a display device.

  In order to solve the above-described problems and achieve the object, a light source device according to the present invention has any one of the following configurations.

[Configuration 1]
A solid-state light-emitting element that is a surface-emitting light source having a reflective film disposed on the back surface side and a light-emitting surface on the front surface side, and a first and a second light-emitting element that face each other in parallel and are substantially perpendicular to the surface portion of the solid-state light-emitting element. A third reflecting surface that is substantially perpendicular to the first reflecting surface and the first reflecting surface, is opposed to the surface portion of the solid state light emitting device, and is inclined with respect to the surface portion of the solid state light emitting device. The reflective film of the solid state light emitting device and the first to third reflective surfaces include a side edge portion on the side of the third reflective surface away from the surface portion of the solid state light emitting device, and the first and second reflective surfaces. A closed polyhedron having an emission opening formed by one side edge of the reflective surface and one side edge of the reflective film, and the emission opening is smaller than the area of the light emitting surface of the solid state light emitting device The light emitted from the solid state light emitting device is transmitted through the first to third reflecting surfaces and the reflecting film. After being reflected by or Re, or without being reflected by these first to third reflecting surface and the reflection film, is characterized in that the emitted outward from the exit aperture.

[Configuration 2]
In the light source device having the configuration 1, the polyhedron formed by the reflective film of the solid-state light emitting element and the first to third reflective surfaces has the same refractive index as that of the outer medium in which the light emitted from the emission opening travels. Or it is filled with the medium which has a refractive index smaller than this, It is characterized by the above-mentioned.

[Configuration 3]
In the light source device having the configuration 1 or the configuration 2, the light emitting surface and the emission opening of the solid state light emitting element are rectangular.

[Configuration 4]
In the light source device having any one of Configurations 1 to 3, the third reflecting surface is a curved surface.

[Configuration 5]
In the light source device having any one of Configurations 1 to 4, the third reflecting surface has a surface facing the solid-state light-emitting element that is a concave cylindrical surface toward the solid-state light-emitting device on the emission opening side. It has an inflection point in the part, and has a convex cylindrical surface toward the solid state light emitting device on the side far from the emission opening.

  The image display apparatus according to the present invention has the following configuration.

[Configuration 6]
A light source device having any one of Configurations 1 to 5, a spatial light modulation element illuminated by light emitted from the light source device, and light that has passed through the spatial light modulation device are incident and an image of the spatial light modulation device And an image forming optical system for forming an image.

  In the light source device according to the present invention having the configuration 1, the light emitted from the solid state light emitting element is reflected by one of the first to third reflecting surfaces and the reflecting film, or after these first to third reflecting surfaces. 3 is not reflected by the reflecting surface and the reflecting film, but is emitted outward from the exit opening having a smaller area than the area of the light emitting surface of the solid light emitting element, so that the light from the solid light emitting element is condensed on the exit opening. It is possible to improve the use efficiency of light and to improve the luminance of illumination light that was dominant in the light source etendue.

  Further, in this light source device, since the light emission distribution of the light source is also made uniform, it is not always necessary to use a large-area solid light-emitting element as the light source. However, the light emission distribution at the boundary surface of these solid state light emitting devices can be made uniform.

  In the light source device according to the present invention having the configuration 2, the polyhedron formed by the reflective film of the solid-state light emitting element and the first to third reflective surfaces is an outer medium in which the light emitted from the emission opening travels. Since it is filled with a medium having a refractive index that is the same as or smaller than the refractive index, there is no reduction in efficiency due to the light emitted from the exit aperture being reflected at the exit aperture.

  In the light source device according to the present invention having the configuration 3, since the light emitting surface and the emission opening of the solid state light emitting element are rectangular, a rectangular object such as a spatial light modulation element in the image display device can be illuminated with high efficiency. Can do.

  In the light source device according to the present invention having the configuration 4, since the third reflecting surface is a curved surface, the light use efficiency is improved, and the luminance of the illumination light that is dominant in the light source etendue can be improved. it can.

  In the light source device according to the present invention having the configuration 5, the surface of the third reflecting surface facing the solid light emitting element is a concave cylindrical surface toward the solid light emitting element on the emission opening side, Since it has an inflection point and has a convex cylindrical surface toward the solid state light emitting device on the side far from the exit aperture, the light utilization efficiency is improved and the brightness of illumination light that was dominant in the light source etendue is improved. Can be made.

  Since the image display device according to the present invention having the configuration 6 includes the light source device having any one of the configurations 1 to 5, the spatial light modulation element is illuminated with high efficiency by the light emitted from the light source device. And a high-luminance image can be displayed.

  That is, the present invention improves the utilization efficiency of light from the light source and improves etendue, thereby reducing the light emission angle from the light source without increasing the amount of emitted light per unit area of the light source. In addition, it is possible to provide a light source device capable of illuminating an object to be illuminated such as a spatial light modulation element with higher luminance, and to provide an image display device using such a light source device. .

  Hereinafter, a configuration of a light source device according to the present invention and an image display device using the light source device will be described in detail.

[First Embodiment of Light Source Device]
FIG. 1 is a perspective view showing the configuration of the light source device according to the first embodiment of the present invention.

  As shown in FIG. 1, this light source device has a solid-state light-emitting element 1 that is a surface-emitting light source. The solid-state light emitting device 1 includes a reflective film 1a disposed on the back surface side and a light emitting layer (light emitting surface) 1b on the front surface side. As such a solid state light emitting device 1, a so-called high brightness LED can be used.

  FIG. 2 is a cross-sectional view showing a configuration of a solid state light emitting element in the light source device according to the present invention.

  In the high-brightness LED, as shown in FIG. 2, a reflective film 1a is formed on the back side of the light emitting layer 1b. Light is emitted from the light emitting layer 1b to the front surface side and the back surface side. The light emitted from the light emitting layer 1b to the surface side is directly emitted to the surface side of the high-brightness LED. The light emitted from the light emitting layer 1b to the back side is reflected by the reflective film 1a, passes through the light emitting layer 1b, and is emitted to the front side. Further, the incident light from the outside to the light emitting layer 1b passes through the light emitting layer 1b, is reflected by the reflective film 1a on the back surface side, passes through the light emitting layer 1b again, and is emitted to the front surface side. In this way, in the high-brightness LED, the light lost by light absorption on the back side in the conventional LED is reflected and emitted to the front side, so that high brightness is achieved.

  Since the light emitting layer 1b of the LED transmits the light having the wavelength emitted by the light emitting layer 1b, the incident light to the LED in this wavelength band is transmitted through the light emitting layer 1b and is reflected by the reflective film 1a on the back surface side. It will be reflected.

  The light emitting layer (light emitting surface) 1b of the solid light emitting element 1 has a rectangular shape of 2 mm × 6 mm, for example.

  The material of the light emitting layer 1b of such an LED is AlGaAs, AlGaInP, GaAsP or the like in the case of red light emission, InGaN or AlGaInP in the case of green light emission, and InGaN in the case of blue light emission. These InGaN-based materials are generally formed by epitaxial growth on the sapphire substrate 1c. The reflective film 1a is formed, for example, by peeling the semiconductor from the sapphire substrate 1c by laser lift-off and planarizing the P-type semiconductor surface. The reflective film 1a can be formed directly on the semiconductor back surface by sputtering or the like. The LED is installed on the silicon substrate 1d with the reflective film 1a facing down, and is fed with power via wire bonding (not shown).

  As shown in FIG. 1, the light source device includes first and second reflecting surfaces 2 and 3 that face each other in parallel and are disposed substantially perpendicular to the surface portion of the solid-state light emitting element 1. Have. These first and second reflecting surfaces 2 and 3 are mirrors in which a reflecting film is formed on the surface of the base material. When an Al film is used as the reflecting film, the reflectance is about 92%, and an Ag film as the reflecting film. The reflectivity when using is about 98%.

  The light source device is substantially perpendicular to the first and second reflecting surfaces 2 and 3, faces the surface portion of the solid light emitting element 1, and is inclined with respect to the surface portion of the solid light emitting element 1. The third reflecting surface 4 is arranged. The third reflecting surface 4 is a mirror configured in the same manner as the first and second reflecting surfaces 2 and 3.

  In this light source device, the reflective film 1a and the first to third reflective surfaces 2, 3, and 4 of the solid state light emitting device 1 constitute a closed polyhedron. The polyhedron includes a side edge portion 4a on the side of the third reflecting surface 4 away from the surface portion of the solid-state light emitting element 1, and one side edge portions 2a and 3a of the first and second reflecting surfaces 2 and 3; A rectangular emission opening 5 formed by one side edge 1e of the reflective film 1a of the solid state light emitting device 1 is provided. The emission opening 5 has a smaller area than the area of the light emitting surface 1 b of the solid state light emitting device 1.

  FIG. 3 is a cross-sectional view showing the configuration of the light source device according to the first embodiment of the present invention.

  FIG. 4 is a cross-sectional view showing another configuration of the light source device according to the first embodiment of the present invention.

  The exit opening 5 is preferably formed substantially perpendicular to the third reflecting surface 4 as shown in FIG. 3, but the third reflecting surface 4 is formed as shown in FIG. However, it does not have to be vertical. Further, in this embodiment, the light emitting surface 1b and the emission opening 5 of the solid state light emitting device 1 are both rectangular, but it is not so limited.

  3 and 4 and FIGS. 6 to 12 to be described later are longitudinal sectional views, and therefore, only the second reflecting surface 3 is represented for the first and second reflecting surfaces 2 and 3. The first reflecting surface 2 is not shown because it is on the near side of the cross section.

  In this embodiment, as shown in FIG. 1, one side edge 1 e of the reflective film 1 a of the solid-state light-emitting element 1, which is a part of the edge of the emission opening 5, It is a short side. Accordingly, two opposite sides (one side edge 1e of the reflective film 1a of the solid light emitting element 1 and the side edge 4a of the third reflective surface 4) of the emission opening 5 are indicated by an arrow A in FIG. Thus, the length is equal to the short side portion of the light emitting surface of the solid state light emitting device 1, and the other two sides indicated by the arrow B in FIG. 1 (one side edge portion of the first and second reflecting surfaces 2 and 3). The length of 2a, 3a) is shorter than the long side part of the light emission surface of the solid light emitting element 1 shown by the arrow C in FIG.

  In this light source device, the light emitted from the solid light emitting element 1 is reflected by one of the first to third reflecting surfaces 2, 3, 4 and the reflective film 1a of the solid light emitting element 1, or Without being reflected by the first to third reflecting surfaces 2, 3, 4 and the reflecting film 1 a, the light is emitted outward from the emission opening 5.

  The polyhedron formed by the reflective film 1a and the first to third reflective surfaces 2, 3 and 4 of the solid-state light emitting element 1 is an outer medium (for example, air) in which the light emitted from the emission opening 5 travels. It is preferably filled with a medium (for example, air) having the same refractive index as that of the refractive index, or a medium having a smaller refractive index.

  By the way, in the light source device using a conventional rod integrator, when the area of the illumination light exit opening is made smaller than the light emission area of the light source, the light beam reflection angle at the interface as the light propagates through the rod. Becomes smaller, and some rays become smaller than the total reflection critical angle at the interface, and cannot be emitted from the exit aperture. On the other hand, in the light source device according to the present invention, the light emitted from the solid state light emitting device 1 is shaped to be emitted from the emission opening 5 with the smallest possible number of reflections, and the light beam that cannot be emitted from the emission opening 5 Is returned to the solid-state light-emitting element 1 and reflected by the reflective film 1 a of the solid-state light-emitting element 1.

  FIG. 5 is a graph showing the relationship between etendue and illumination intensity in the light source device according to the present invention.

  When the characteristic curve (etendue curve) of the etendue in this light source device is shown, as indicated by the solid line L1 in FIG. 5, the characteristic curve L2 in the solid light-emitting element 1 alone indicated by the alternate long and short dash line in FIG. The emitted light intensity (relative luminance) is high.

As described above, etendue is represented by Sπsin ² θ (∵S is a light emitting area, and θ is a light radiation angle). The characteristic curve of etendue is that when the etendue (horizontal axis) is set to a predetermined value, that is, when the light emission area S and the light radiation angle θ are set to predetermined values, the emitted light intensity (relative luminance) ( Vertical axis). The light emitting area S is the area of the emission opening 5 in the light source device, and the area of the light emitting surface 1b in the solid light emitting element 1 alone.

  A characteristic curve L3 indicated by a dotted line in FIG. 5 is an etendue characteristic curve in a light source device as a comparative example. In this comparative example, the first and second reflecting surfaces 2 and 3 are not parallel to each other, and one side edge 1e of the reflecting film 1a of the solid state light emitting device 1 and the third reflecting surface 4 side. The edge 4a has a different length. In this case, as compared with the light source device according to the present invention, the number of internal reflections in the polyhedron formed by the reflective film 1a and the first to third reflective surfaces 2, 3, 4 of the solid state light emitting device 1 is large. Thus, the amount of emitted light is low according to the reflectance of each reflecting surface. That is, in the light source device according to the present invention, since the first and second reflection surfaces 2 and 3 are parallel to each other, the reflection film 1a and each reflection surface 2 are emitted before the light beam is emitted from the emission opening 5. , 3, 4 are less reflected in the polyhedron, and the reflected light is less likely to return to the solid-state light emitting device 1, so that light can be emitted with high efficiency.

[Second Embodiment of Light Source Device]
FIG. 6 is a cross-sectional view showing the configuration of the light source device according to the second embodiment of the present invention.

  In the light source device according to the present invention, as shown in FIG. 6, the first to third reflecting surfaces 2, 3, 4 may be arranged avoiding the wire bonding 6, 6 to the solid light emitting element 1. . That is, in this light source device, the solid state light emitting device 1 is housed in a package 7 that covers the wire bondings 6 and 6, and the reflecting surfaces 2, 3, and 4 are disposed on the package 7. In other words, each of the reflection surfaces 2, 3, and 4 is arranged so as to avoid the wire bonding 6 and 6, but is closed by each of the reflection surfaces 2, 3, 4 and the package 7. A polyhedron is constructed.

  Also in this case, the light emitted from the solid light emitting element 1 is reflected by one of the first to third reflecting surfaces 2, 3, 4 and the reflective film 1a of the solid light emitting element 1, or these Without being reflected by the first to third reflecting surfaces 2, 3, 4 and the reflecting film 1 a, the light is emitted outward from the emission opening 5.

[Third Embodiment of Light Source Device]
FIG. 7 is a cross-sectional view showing the configuration of the light source device according to the third embodiment of the present invention.

  As shown in FIG. 7, the light source device according to the present invention may be configured by interposing a light pipe 8 a between the solid state light emitting device 1 and each of the reflection surfaces 2, 3, 4. The light pipe 8a is a hollow tubular member having a rectangular cross section, and all four inner wall surfaces are reflecting surfaces.

  The reflecting surfaces 2, 3 and 4 are arranged on the end surface of the light pipe 8a, and the reflecting surfaces 2, 3, 4 and the reflecting film 1a and the light pipe 8a constitute a closed polyhedron. By interposing this light pipe 8a, when there is wire bonding to the third reflecting surface 4 and the solid state light emitting device 1, interference with it can be prevented.

  Also in this case, the light emitted from the solid light emitting element 1 is reflected by any one of the first to third reflecting surfaces 2, 3, 4, the reflective film 1 a of the solid light emitting element 1, and the inner wall surface of the light pipe 8 a. Or after being reflected by the first to third reflecting surfaces 2, 3, 4, the reflecting film 1 a, and the inner wall surface of the light pipe 8 a.

[Fourth Embodiment of Light Source Device]
FIG. 8 is a cross-sectional view showing the configuration of the light source device according to the fourth embodiment of the present invention.

  As shown in FIG. 8, the light source device according to the present invention is configured by disposing a transparent member 9 in a light pipe 8 a interposed between the solid light emitting element 1 and each of the reflecting surfaces 2, 3, 4. Also good. The transparent member 9 is a transparent parallel plate, for example. By disposing the transparent member 9, when there is wire bonding to the third reflecting surface 4 and the solid light emitting element 1, interference with it can be prevented.

  The reflecting surfaces 2, 3, 4 are arranged on the transparent member 9, and the reflecting surfaces 2, 3, 4, the reflecting film 1 a and the inner surface of the transparent member 9 constitute a closed polyhedron.

  Also in this case, the light emitted from the solid light emitting element 1 is reflected by any one of the first to third reflecting surfaces 2, 3, 4, the reflective film 1 a of the solid light emitting element 1, and the inner surface of the transparent member 9. After that, or without being reflected by the first to third reflection surfaces 2, 3, 4, the reflection film 1 a and the inner surface of the transparent member 9, the light is emitted outward from the emission opening 5.

[Fifth Embodiment of Light Source Device]
FIG. 9 is a cross-sectional view showing the configuration of the light source device according to the fifth embodiment of the present invention.

  As shown in FIG. 9, the light source device according to the present invention may be configured by extending from the emission opening 5 and providing a light pipe 8 b or a rod integrator. The light pipe 8b is a hollow tubular member having a rectangular cross section, and all four inner wall surfaces are reflecting surfaces. Each reflective surface 2, 3, 4, the reflective film 1a, and the light pipe 8b constitutes a closed polyhedron.

  Also in this case, the light emitted from the solid light emitting element 1 is reflected by any one of the first to third reflecting surfaces 2, 3, 4, the reflective film 1 a of the solid light emitting element 1, and the inner wall surface of the light pipe 8 b. Or after being reflected by the first to third reflecting surfaces 2, 3, 4, the reflecting film 1 a and the inner wall surface of the light pipe 8 b, the light is emitted outward from the end surface of the light pipe 8 b.

  FIG. 10: is sectional drawing which shows the other structure in 5th Embodiment of the light source device which concerns on this invention.

  FIG. 11 is a sectional view showing still another configuration in the fifth embodiment of the light source device according to the present invention.

  Furthermore, in this light source device, as shown in FIGS. 10 and 11, the light pipe 8b provided to extend to the emission opening 5 may be tapered. 10 and 11, the light pipe 8b that gradually increases in diameter in the light traveling direction is provided. However, a light pipe that gradually decreases in the light traveling direction may be provided.

  The light emitted from such a light pipe 8b illuminates, for example, the spatial light modulation element 13, which becomes an object to be illuminated, via the field lenses 11 and 12.

[Sixth Embodiment of Light Source Device]
FIG. 12 is a cross-sectional view showing the configuration of the light source device according to the sixth embodiment of the present invention.

  In the light source device according to the present invention, as shown in FIG. 12, the third reflecting surface 4 may be configured as a curved surface, for example, a curved surface having a concave on the solid light emitting element 1 side. In this case, the curved surface formed by the third reflecting surface 4 is a curved surface such as a cylindrical surface that is linear in a direction parallel to the side edge portion 4a that forms part of the exit opening 5 of the reflecting surface 4. It may be a spherical surface, a paraboloid, or a higher order curved surface. Even in this case, each of the reflecting surfaces 2, 3, 4 and the reflecting film 1a constitutes a closed polyhedron.

  Also in this case, the light emitted from the solid light emitting element 1 is reflected by one of the first to third reflecting surfaces 2, 3, 4 and the reflective film 1a of the solid light emitting element 1, or these Without being reflected by the first to third reflecting surfaces 2, 3, 4 and the reflecting film 1a, the light is emitted outward from the end surface of the light pipe 8b.

  Further, when the third reflecting surface 4 is curved as described above, the light pipe 8a interposed between the solid light emitting element 1 and each reflecting surface 2, 3, 4 or the exit opening 5 as described above. You may provide the light pipe 8b extended from.

[Seventh Embodiment of Light Source Device]
FIG. 13: is sectional drawing which shows the structure in 7th Embodiment of the light source device which concerns on this invention.

  The light source device according to the present invention can be configured by optimizing the shape of the third reflecting surface 4 so that the light utilization efficiency is maximized. As shown in FIG. 13, the shape of the third reflecting surface 4 in this case is such that the surface facing the solid light emitting element 1 is a concave cylindrical surface toward the solid light emitting element 1 on the emission opening 5 side. It has an inflection point at the center, and has a convex cylindrical surface toward the solid-state light emitting device 1 on the side far from the injection opening 5. The curved surface formed by the third reflecting surface 4 is a curved surface such as a cylindrical surface that is linear in a direction parallel to the side edge portion 4 a that forms part of the exit opening 5 of the reflecting surface 4.

In the case where the area of the emission opening 5 is 25% of the area of the solid state light emitting device 1 and the reflectance of the reflective film 1a of the solid state light emitting device 1 is 60%, the optimized third reflective surface 4 The shape is a shape represented by the following formula.
Y = B * sin ^1.25 (Xπ / 4C)

  Here, B is the height of the emission opening 5 from the solid state light emitting device 1 (the two sides indicated by the arrow B in FIG. 13 (one side edge portions 2a and 3a of the first and second reflecting surfaces 2 and 3). C) indicates the length of the long side portion of the light emitting surface of the solid state light emitting device 1 indicated by arrow C in FIG. 13, and X indicates the distance from the side of the solid state light emitting device 1 far from the emission opening 5. Y represents the height from the solid state light emitting device 1 to the third reflecting surface 4 at the distance X.

  The inflection point in this curve is the central portion of the third reflecting surface 4 (X = (C / 2) position). Moreover, this curve becomes a shape close to a straight line as the reflectance of the reflective film 1a of the solid state light emitting device 1 increases.

[Embodiment of Image Display Device]
FIG. 14 is a plan view showing the configuration of the image display device 30 according to the embodiment of the present invention.

  As shown in FIG. 14, the image display device 30 according to the present invention includes the light source devices 11R, 11G, and 11B according to the present invention described above, and the spatial light modulation elements 10R that are illuminated by the light emitted from the light source device. 10G and 10B, and an imaging optical system 13 on which light having passed through these spatial light modulation elements 10R, 10G, and 10B is incident and forms images of the spatial light modulation elements 10R, 10G, and 10B. . The image display device 30 illuminates the spatial light modulation elements 10R, 10G, and 10B with the light source devices 11R, 11G, and 11B corresponding to the spatial light modulation elements 10R, 10G, and 10B. This is an image display device that displays a color image by color-combining the modulated lights that have passed through 10G and 10B to form an image.

  Each of the spatial light modulators 10R, 10G, and 10B displays the red component, the green component, and the blue component of the display image, respectively, and polarization-modulates the illumination light according to these images. In this embodiment, each of the spatial light modulators 10R, 10G, and 10B is of a reflective type, and reflects incident illumination light by polarization modulation.

  As described above, each light source device 11R, 11G, and 11B includes a solid light emitting element and first to third reflecting surfaces, and includes a rod integrator 8b that extends to the emission opening. ing. In each of the light source devices 11R, 11G, and 11B, the solid light emitting element is provided on the heat sink 20.

  Each of the light source devices 11R, 11G, and 11B illuminates the spatial light modulator 10R that displays a red component image with red illumination light, and illuminates the spatial light modulator 10G that displays a green component image with green illumination light. Then, the spatial light modulation element 10B displaying the blue component image is illuminated with blue illumination light.

  Illumination light emitted from the red light source device 11R is incident on the red reflective spatial light modulator 10R via the relay lens 12R, the field lens 13R, and the wire grid 14R. The red illumination light is polarized and modulated in accordance with the image signal of the red component by the reflective spatial light modulation element 10R, reflected, reflected by the wire grid 14R, and incident on the color synthesis prism 15 as red image light. .

  The illumination light emitted from the blue solid light emitting element 11B is incident on the blue reflective spatial light modulation element 10B via the relay lens 12B, the field lens 13B, and the wire grid 14B. The blue illumination light is polarization-modulated and reflected by the reflective spatial light modulator 10B in accordance with the blue component image signal, reflected by the wire grid 14B, and incident on the color synthesis prism 15 as blue image light. .

  The illumination light emitted from the green solid light emitting element 11G is incident on the green reflective spatial light modulation element 10G via the relay lens 12G, the field lens 13G, and the wire grid 14G. The green illumination light is polarized and modulated by the reflective spatial light modulation element 10G in accordance with the green component image signal, reflected, reflected by the wire grid 14G, and incident on the color synthesis prism 15 as green image light. .

  The red, green, and blue image lights incident on the color combining prism 15 are color combined and incident on a projection lens 16 serving as an imaging optical system. The projection lens 16 projects image light of each color on a screen (not shown), enlarges it, forms an image, and displays an image.

It is a perspective view which shows the structure in 1st Embodiment of the light source device which concerns on this invention. It is sectional drawing which shows the structure of the solid light emitting element in the light source device which concerns on this invention. It is sectional drawing which shows the structure in 1st Embodiment of the light source device which concerns on this invention. It is sectional drawing which shows the other structure in 1st Embodiment of the light source device which concerns on this invention. It is a graph which shows the relationship between etendue and illumination intensity in the light source device which concerns on this invention. It is sectional drawing which shows the structure in 2nd Embodiment of the light source device which concerns on this invention. It is sectional drawing which shows the structure in 3rd Embodiment of the light source device which concerns on this invention. It is sectional drawing which shows the structure in 4th Embodiment of the light source device which concerns on this invention. It is sectional drawing which shows the structure in 5th Embodiment of the light source device which concerns on this invention. It is sectional drawing which shows the other structure in 5th Embodiment of the light source device which concerns on this invention. It is sectional drawing which shows the further another structure in 5th Embodiment of the light source device which concerns on this invention. It is sectional drawing which shows the structure in 6th Embodiment of the light source device which concerns on this invention. It is sectional drawing which shows the structure in 7th Embodiment of the light source device which concerns on this invention. It is a top view which shows the structure in embodiment of the image display apparatus which concerns on this invention. It is a side view which shows the structure of the conventional light source device (fly eye integrator). It is a side view which shows the structure of the conventional light source device (rod integrator). It is a side view which shows the structure of the conventional light source device (expansion taper-shaped light pipe). It is a side view which shows the structure of the conventional light source device (reduction taper-shaped light pipe).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Solid light emitting element 1a One side edge part of a reflecting film 2 1st reflective surface 2a One side edge part of 1st reflective surface 3 2nd reflective surface 3a One side edge part of 2nd reflective surface 4 3rd Reflective surface 4a Side edge of third reflective surface 5 Ejection opening 10R Spatial light modulator 10G Spatial light modulator 10B Spatial light modulator 11R Light source device 11G Light source device 11B Light source device 16B Projection lens 30 Image display device

Claims (6)

A solid-state light-emitting element that is a surface-emitting light source having a reflective film disposed on the back side and a light-emitting surface on the front side;
First and second reflecting surfaces that face each other in parallel and are disposed substantially perpendicular to the surface portion of the solid-state light-emitting element;
A third reflecting surface that is substantially perpendicular to the first and second reflecting surfaces, faces the surface portion of the solid state light emitting device, and is inclined with respect to the surface portion of the solid state light emitting device. And
The reflective film of the solid-state light emitting element and the first to third reflective surfaces are a side edge portion of the third reflective surface on a side away from the surface portion of the solid-state light emitting element and the first and second reflective surfaces. A closed polyhedron having an exit opening formed by one side edge of the surface and one side edge of the reflective film;
The injection opening has a smaller area than the area of the light emitting surface of the solid state light emitting device,
The light emitted from the solid state light emitting device is reflected by one of the first to third reflecting surfaces and the reflecting film, or is reflected by the first to third reflecting surfaces and the reflecting film. The light source device is emitted outward from the emission opening. The polyhedron formed by the reflective film of the solid-state light emitting element and the first to third reflective surfaces has the same or smaller refractive index as the outer medium through which the light emitted from the emission aperture travels. The light source device according to claim 1, wherein the light source device is filled with a medium having a refractive index. 3. The light source device according to claim 1, wherein the light emitting surface and the emission opening of the solid state light emitting element are rectangular. The light source device according to any one of claims 1 to 3, wherein the third reflecting surface is a curved surface. The third reflective surface has a surface facing the solid-state light-emitting element, which is a concave cylindrical surface toward the solid-state light-emitting element on the emission opening side, has an inflection point at the center, and the emission opening. 5. The light source device according to claim 1, wherein the light source device has a convex cylindrical surface toward the solid state light emitting element on a side far from the light source. A light source device according to any one of claims 1 to 5,
A spatial light modulation element illuminated by light emitted from the light source device;
An image display apparatus comprising: an imaging optical system configured to receive light having passed through the spatial light modulation element and form an image of the spatial light modulation element.

Images