JP2013120250A - Projection video display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a projection video display device that utilizes a laser beam having high luminance efficiency as excitation light.SOLUTION: The present invention relates to a projection video display device provided with an illumination optical system 10 in which fluorescent light or phosphorescent light is emitted by irradiating a fluorescent substance 15 or a phosphor with a laser beam from a laser emitter 11A as excitation light and the fluorescent light or the phosphorescent light is at least a part of color light in illumination light. The illumination optical system 10 is configured such that a diffusion plate, preferably an anisotropic diffusion plate 14, is provided between the laser emitter 11A and the fluorescent substance 15 or the phosphor, and, after the laser beam is transmitted by the anisotropic diffusion plate 14, the fluorescent substance 15 or the phosphor is irradiated therewith. The laser emitter 11A, e.g., a laser semiconductor is utilized.

Description

  The present invention relates to a projection display apparatus, and in particular, irradiates fluorescent light or phosphorescence emitted from a phosphor or phosphor by irradiating the phosphor or phosphor with laser light as excitation light from a laser emitter. The present invention relates to a projection display apparatus used as illumination light.

  Conventionally, by emitting laser light as excitation light from a laser emitter to a phosphor, fluorescent light is emitted from the phosphor, and this is modulated as illumination light to generate image light, and this image light is projected. There are various types of projection-type image display devices that perform magnification projection using a lens. Examples of such a projection display apparatus include those described in Patent Document 1, Patent Document 2, and the like.

JP 2011-215531 A JP 2009-277516 A

  However, in such a conventional projection display apparatus, the light density is increased because the irradiation area of the laser beam on the surface of the laser emitter is small and the light collection efficiency is high due to the strong directivity of the laser beam. Further, since the phosphor has temperature dependency, there is a problem that when the laser beam is irradiated, the temperature of the irradiated portion is increased and the light emission efficiency is decreased.

  An object of the present invention is to solve such problems in the prior art, and to provide an efficient projection display apparatus that uses laser light as excitation light.

  The projection display apparatus according to the first aspect of the present invention emits fluorescent light or phosphorescent light by irradiating a fluorescent light or phosphor with laser light from a laser emitter as excitation light. Or a projection-type image display device having an illumination optical system that uses phosphorescent light as illumination light of at least a part of color light, wherein the illumination optical system includes a diffusion plate between a laser emitter and a phosphor or phosphor. And the laser light from the laser emitter is transmitted through the diffuser plate to irradiate the phosphor or phosphor.

  According to such a configuration, since the laser light irradiated to the phosphor or phosphor is diffused by the diffusion plate, the light density of the laser light irradiation portion on the surface of the phosphor or phosphor is reduced, and laser light irradiation is performed. The temperature rise of the phosphor or phosphor in the part is suppressed. Thereby, the luminous efficiency of the phosphor or phosphor can be improved.

  According to a second aspect of the present invention, there is provided a projection image display device according to the first aspect, wherein the diffuser plate is an anisotropic diffuser plate, thereby collecting the laser light focused on the surface of the phosphor or phosphor. The light surface shape is an ellipse, and the short side dimension of the ellipse is approximated to the short side dimension of the rectangular incident part that collects and enters the fluorescent light or phosphorescent light in the subsequent optical system. And

  If comprised in this way, let the condensing surface shape of the laser beam condensed on the surface of a fluorescent substance or a phosphor be an ellipse, and let the short side dimension of this ellipse be the said fluorescence light or phosphorescence light in an optical system of a back | latter stage. Can be approximated to the short side dimension of the rectangular incident portion where the light is condensed and incident. Therefore, fluorescent light or phosphorescent light can be efficiently taken into the rectangular incident portion, and the light utilization efficiency can be improved. When a normal isotropic diffusion plate is used as the diffusion plate, the shape of the condensing surface of the laser light collected on the surface of the phosphor or phosphor is circular, so that the laser from the laser emitter is used. When light is diffused using a diffusion plate, a light beam that is not taken into the incident portion of the subsequent optical system is generated, and the light utilization efficiency is reduced.

  According to a third aspect of the present invention, in the projection display apparatus according to the second aspect, the illumination optical system includes a light source for red light, a light source for blue light, and a light source for green light. The light source for the light is composed of a red light emitting diode, the light source for the blue light is composed of a blue light emitting diode, and the light source for the green light is irradiated with the laser light from the laser emitter as the excitation light on the phosphor or phosphor. The gist of the present invention is to use green fluorescent light or phosphorescent light emitted from the phosphor or phosphor.

  According to such a configuration, inexpensive light emitting diodes are used as the light source for red light and the light source for blue light that can easily obtain a desired high output even by the light emitting diode. On the other hand, a laser light emitter is used for a light source for green light, which is difficult to obtain a desired high output with a light emitting diode, and laser light emitted from the laser light emitter is irradiated as an excitation light to a phosphor or phosphor, Green fluorescent light or phosphorescent light emitted from a phosphor or phosphor is used. Therefore, it is possible to obtain a light source with sufficient output while giving priority to the use of the light emitting diode and limiting the use of the laser emitter.

  According to a fourth aspect of the present invention, in the projection display apparatus according to the second or third aspect, the illumination optical system uses a fly-eye lens and a polarizing beam splitter, and the polarizing beam splitter has a strip shape. The gist of the present invention is that the allowable incidence surface is configured to be the rectangular incident portion.

  If comprised in this way, the condensing surface shape of the fluorescence light or phosphorescence light condensed on the entrance allowable surface formed in the strip shape of a polarization beam splitter is made into an ellipse, and the short side dimension of the ellipse is made into a polarization beam. It can be configured to approximate the short side dimension of the entrance allowable surface of the splitter. Therefore, light can be efficiently taken into the polarization beam splitter and the light utilization efficiency can be improved.

  Note that, in the projection display apparatus using the fly-eye lens and the polarization beam splitter as described above, the fluorescent light or phosphorescent light emitted from the phosphor or phosphor upon irradiation with the laser light is the second lens of the fly-eye lens. Focused on the array surface. In addition, the incident allowable surface that is a rectangular incident portion of the illumination light in the polarization beam splitter is configured to capture the light collected on the second lens array surface of the fly-eye lens without leaking, so that the first eye of the fly-eye lens can be captured. Two lens arrays are arranged close to the surface. For this reason, the condensing surface shape of the fluorescent light or phosphorescent light that is condensed and incident on the incident allowable surface of the polarization beam splitter is the condensing of the laser light that is condensed and irradiated on the surface of the phosphor or phosphor It is almost the same as the surface shape.

  Therefore, when a normal isotropic diffuser plate is used, the shape of the condensing surface of the fluorescent light or phosphorescent light collected on the entrance allowable surface of the polarizing beam splitter becomes a substantially circular shape. If an attempt is made to increase the angle, a light beam that is not taken into the polarization beam splitter is generated, and the light utilization efficiency is lowered. Further, if the diameter of the condensing surface shape of the fluorescent light or phosphorescent light is adjusted to the length in the short side direction on the incidence allowable surface of the polarizing beam splitter, the diffusion angle becomes small and it becomes difficult to obtain a good diffusion effect.

  According to a fifth aspect of the present invention, in the projection display apparatus according to the second or third aspect, the illumination optical system includes a rod-shaped or cylindrical light guide member having a rectangular incident surface. And it makes it a summary that the entrance plane of this light guide member is comprised so that it may become the said rectangular entrance part.

  If comprised in this way, the condensing surface shape of the fluorescence light or phosphorescent light condensed on the incident surface of the rod-shaped or cylindrical light guide member formed in the rectangular shape of the incident surface is formed in an ellipse, Furthermore, the short side dimension of the ellipse can be approximated to the short side dimension of the incident surface of the light guide member. Therefore, light can be efficiently taken into the light guide member and the light utilization efficiency can be improved.

  In addition, in the projection display apparatus using the rod-shaped or cylindrical light guide member whose incident surface is rectangular in this way, the fluorescent light or phosphorescent light emitted from the phosphor or phosphor by irradiation of the laser light is: It is condensed on the incident surface of the light guide member. For this reason, the shape of the condensing surface of the fluorescent light or phosphorescent light collected on the incident surface of the light guide member is substantially the same as the shape of the condensing surface of the laser light condensed on the surface of the phosphor or phosphor. Become. Therefore, when a normal isotropic diffusion plate is used, the light collecting surface shape of the fluorescent light or phosphorescent light collected on the incident surface of the light guide member is substantially circular, so that light is efficiently captured. Therefore, it is difficult to increase the diffusion angle. However, when an anisotropic diffusion plate is used, the shape of the light collecting surface of the fluorescent light or phosphorescent light collected on the incident surface of the light guide member is an ellipse, and the short side dimension of this ellipse is the light guide member. Therefore, the light can be efficiently taken into the optical system while obtaining a good diffusion effect.

  A sixth aspect of the present invention is the projection display apparatus according to the fourth aspect, wherein a three-plate projection type using a red light liquid crystal panel, a green light liquid crystal panel and a blue light liquid crystal panel as the light modulation device. The gist is that it is formed in a video display device.

  According to such a configuration, since the laser emitter is used as at least a part of the light source of the illumination optical system, the three-plate projection type having a light source that has a long life, does not require a high voltage, and emits light with high efficiency. A video display device can be provided.

  According to a seventh aspect of the present invention, there is provided the projection display apparatus according to the fifth aspect, wherein the projection display apparatus uses a reflective display element composed of a micromirror element as a light modulation device. The gist.

  According to such a configuration, since a laser emitter can be used as at least a part of the light source of the illumination optical system, the light source has a long life, does not require a high voltage, and emits light efficiently. A projection display apparatus using a reflective display element made of a micromirror as a light modulator can be provided.

  According to the projection display apparatus of the present invention, the laser light irradiated to the phosphor or phosphor is diffused by the diffusion plate, so that the light density of the laser beam irradiated portion on the surface of the phosphor or phosphor is reduced. At the same time, the temperature rise of the phosphor or phosphor in the laser light irradiation portion is suppressed. Thereby, the luminous efficiency of the phosphor or phosphor can be improved.

1 is a system diagram of an optical system of a projection display apparatus according to Embodiment 1 of the present invention. It is explanatory drawing of the incident state of the light beam to the entrance allowable surface of the polarization beam splitter in the projection type image display apparatus. It is drawing which shows the condensing surface shape of the fluorescence light in the whole entrance permissible surface of the polarization beam splitter, (a) is a thing at the time of using an isotropic diffuser, (b) is anisotropic diffusion It is a thing when a board is used. FIG. 3 is a partial enlarged view of a b portion showing the shape of a fluorescent light condensing surface on the entrance allowable surface of the polarization beam splitter, wherein (a) is a case where an isotropic diffuser is used, and (b) is anisotropic. This is the case where a functional diffusion plate is used. It is a systematic diagram of the optical system of the projection type video display apparatus concerning Embodiment 2 of this invention.

(Embodiment 1)
Hereinafter, a projection display apparatus according to Embodiment 1 of the present invention will be described with reference to FIGS. This projection display apparatus is a three-plate liquid crystal projection display apparatus using a liquid crystal panel. The projection display apparatus includes an illumination optical system 10 that emits illumination light, a color separation optical system 20 that separates an illumination light beam emitted from the illumination optical system 10 into a plurality of color light beams, and images each color light beam. It comprises a light modulation optical system 30 that modulates light according to information, a color synthesis optical system 40 that synthesizes each modulated color beam, and a projection optical system 50 that projects the synthesized image light.

  The illumination optical system 10 according to the present embodiment uses a blue light emitting diode (LED) 11B as a blue light source and a red light emitting diode (LED) 11R as a red light source. In addition, the illumination optical system 10 irradiates the phosphor 15 as excitation light with the laser light emitted from the laser emitter 11A as a green light source, thereby exciting the phosphor 15 to generate green fluorescent light. A light source is used.

The blue light emitting diode 11B and the red light emitting diode 11R are disposed so that the optical axes are orthogonal to each other, and the first dichroic mirror 13R is disposed at the intersection of the optical axes.
The first dichroic mirror 13R transmits a light beam in a blue wavelength region and reflects a light beam in another wavelength region. Therefore, in this embodiment, the first dichroic mirror 13R transmits blue light in the blue wavelength range emitted from the blue light emitting diode 11B in a straight line, and red light in the red wavelength range emitted from the red light emitting diode 11R in blue. It arrange | positions so that it may reflect in the direction opposite to the position of the light emitting diode 11B. Note that collimating lenses 12B and 12R are disposed between the blue light emitting diode 11B and the first dichroic mirror 13R and between the red light emitting diode 11R and the first dichroic mirror 13R, respectively. Blue light and red light are collimated by the collimating lenses 12B and 12R before reaching the first dichroic mirror 13R.

  A second dichroic mirror 13G is disposed following the first dichroic mirror 13R. The second dichroic mirror 13G reflects a light beam in the green wavelength region and transmits a light beam in another wavelength region. Therefore, the blue light emitted from the blue light emitting diode 11B and the red light emitted from the red light emitting diode 11R pass through the second dichroic mirror 13G and go straight.

  The laser emitter 11A is composed of a plurality of blue laser diodes arranged in an array. The second dichroic mirror 13G is located in front of the laser emitter 11A, and the optical axis of the laser emitter 11A is blue. It arrange | positions so that the optical axis of the light emitting diode 11B may orthogonally cross. An anisotropic diffusion plate 14 is disposed between the laser emitter 11A and the second dichroic mirror 13G. Further, the collimating lens 12A and the phosphor 15 are arranged in series in front of the second dichroic mirror 13G. The phosphor 15 is obtained by forming a phosphor layer on the surface of a reflection mirror.

  The anisotropic diffusion plate 14 diffuses the transmitted light beam and is formed so that the diffusion angle differs depending on the direction. Such an anisotropic diffusion plate 14 has a relief hologram pattern surface structure on the surface of a substrate such as polycarbonate (PC), polyester acrylic, or glass, for example. It is intended to diffuse. In addition, by appropriately changing the pattern shape, the diffusion angle can be adjusted depending on the direction. Therefore, by setting the pattern shape, the surface shape of the substantially circular laser beam that passes through the anisotropic diffusion plate 14 can be changed to an arbitrary elliptical shape.

The phosphor 15 is made of a YAG material, and emits green fluorescent light when irradiated with blue laser light as excitation light.
The blue laser light emitted from the laser emitter 11A is diffused by passing through the anisotropic diffusion plate 14, and its surface shape is diffused and deformed to a preset shape and size. Then, the blue laser light passes through the second dichroic mirror 13G and the collimating lens 12A, and is condensed and irradiated on the surface of the phosphor 15. At this time, the size of the condensing surface shape of the laser light condensed on the surface of the phosphor 15 is larger than that when the anisotropic diffusion plate 14 is not provided, and is condensed on the surface of the phosphor 15. The condensing surface shape of the laser light is deformed into a predetermined elliptical shape by using the anisotropic diffusion plate 14. In this manner, green light having a desired light emitting surface shape is generated by irradiating with blue laser light as excitation light. Further, the generated green light is reflected to the second dichroic mirror 13G by the reflection mirror to which the phosphor 15 is applied. Therefore, this green light is also combined with the above-mentioned red light and blue light and applied to the fly-eye lens 16.

  As partially shown in FIG. 2, the fly-eye lens 16 is composed of a first lens array 16a and a second lens array 16b that are composed of a plurality of cell lens groups formed in a grid pattern. The light beam applied to the fly-eye lens 16 is divided into a plurality of minute partial light beams by the plurality of cell lenses in the first lens array 16a. Then, each of the plurality of partial light beams emitted from the first lens array 16a is condensed on the cell lens of the corresponding second lens array 16b. The condensed light beam is designed to irradiate the entire surface of the liquid crystal light valve, which will be described later, and this causes the partial luminance unevenness present in the light beam emitted from the light source to be averaged, so that the center of the screen is The difference in the amount of light at the periphery is reduced.

  As shown in FIG. 2, the polarizing beam splitter 17 disposed behind the fly-eye lens 16 has a plurality of rod-shaped prism pieces 17a and 17b whose cross sections are parallelograms joined together. That is, rod-shaped prism pieces 17a to which light from the fly-eye lens 16 is directly incident and rod-shaped prism pieces 17b to which light from the fly-eye lens 16 is not directly incident are alternately arranged and pasted. Therefore, on the surface of the polarizing beam splitter 17 on the fly eye lens 16 side, the surface of the rod-shaped prism piece 17a on which the light from the fly eye lens 16 is directly incident is formed in an elongated rectangular shape, that is, a strip shape. In the present invention, the strip-shaped surface forms a rectangular incident portion of the light beam in the optical system at the rear stage of the light source, and is referred to as an incident allowable surface F. In addition, the incident permissible surface F is formed so as to be arranged in parallel with a rod-shaped prism piece 17b on which light is not directly incident, sandwiched therebetween.

  Further, in the polarizing beam splitter 17, a reflective film 17c is formed on the bonding surface of the rod-shaped prism piece 17a and the rod-shaped prism piece 17b. The reflection film 17c is subjected to half mirror processing and mirror surface processing, and as shown in the drawing, one of P-polarized light and S-polarized light among the light beams incident from the fly-eye lens 16, for example, The P-polarized light is transmitted and the other S-polarized light is reflected. A retardation plate 17d is attached to the exit surface of the rod-shaped prism piece 17b where light is not directly incident. The phase difference plate 17d converts the P-polarized light transmitted therethrough into S-polarized light. Since the polarization beam splitter 17 is configured in this way, the S-polarized light taken in from the incidence allowable surface F is reflected twice by the reflection film 17c, and is not converted and remains as the S-polarized light in the rod-shaped prism piece 17a. The light is emitted from the emission side surface. Further, the P-polarized light taken in from the entrance allowable surface F is transmitted through the reflection film 17c and the rod-shaped prism piece 17b, and then is transmitted through the phase difference plate 17d to be converted to S-polarized light, and emitted from the rod-shaped prism piece 17a. The light is emitted from the side surface.

  The polarization beam splitter 17 is configured as described above. As shown in FIG. 2, the polarization beam splitter 17 divides the light beam condensed on the cell lens of the second lens array 16 b of the fly-eye lens 16 into a plurality of strips. In this case, all the captured light fluxes are aligned and emitted in one direction of polarized light. For this reason, the polarization beam splitter 17 is configured so that the light condensed on the cell lens of the second lens array 16b of the fly-eye lens 16 can be individually taken into the incidence allowable plane F of the polarization beam splitter 17. It is arranged close to the eye lens 16.

  In this way, the light flux (illumination light) emitted from each cell lens of the second lens array 16b of the fly-eye lens 16 is taken into the entrance allowable surface F of the polarization beam splitter 17 formed in a strip shape. The green light taken into the allowable incidence surface F is diffused in an elliptical shape by the anisotropic diffusion plate 14 and the short side dimension of the elliptical shape is shorter than the allowable incidence surface F of the polarization beam splitter 17. It is formed so as to approximate the side dimension (see FIGS. 3B and 4B, which will be described in detail later). The light beam taken into the polarization beam splitter 17 is configured to be aligned with predetermined polarized light and emitted to the color separation optical system 20 through the condenser lens 18.

  As shown in FIG. 1, the color separation optical system 20 includes a third dichroic mirror 21, a fourth dichroic mirror 22, reflection mirrors 23, 24, and 25, relay lenses 26 and 27, condenser lenses 28R, 28G, and 28B. And has a function of separating the illumination light emitted from the illumination optical system 10 into red light, green light, and blue light.

  The third dichroic mirror 21 transmits red light and reflects green light and blue light. The red light that has passed through the third dichroic mirror 21 is reflected by the reflecting mirror 23, passes through the condenser lens 28R, and is guided to the red light liquid crystal light valve 30R. The condenser lens 28R is set so that a plurality of partial light beams from the illumination optical system 10 are condensed on the red light liquid crystal light valve 30R. The condenser lenses 28G and 28B disposed on the incident side of the green light liquid crystal light valve 30G and the blue light liquid crystal light valve 30B, which will be described later, are also set in the same manner, although the color light is different from that of the condenser lens 28R.

  Of the green light and blue light reflected by the third dichroic mirror 21, green light is reflected by the fourth dichroic mirror 22, passes through the condenser lens 28G, and is guided to the green light liquid crystal light valve 30G. On the other hand, the blue light is transmitted through the fourth dichroic mirror 22, is sequentially transmitted through the relay lens 26, the reflection mirror 24, and the relay lens 27, and is guided to the blue light liquid crystal light valve 30B.

  The light modulation optical system 30 includes a red light liquid crystal light valve 30R, a green light liquid crystal light valve 30G, and a blue light liquid crystal light valve 30B. The liquid crystal light valve for red light 30R, the liquid crystal light valve for green light 30G and the liquid crystal light valve for blue light 30B are respectively a transmissive liquid crystal panel, an incident side polarizing plate disposed on the incident side of the liquid crystal panel, and a liquid crystal panel. It is comprised from the output side polarizing plate etc. which are arrange | positioned at the output side.

  The color synthesizing optical system 40 includes a cross dichroic prism 41 and the like. The cross dichroic prism 41 includes a reflective surface that reflects red light and a reflective surface that reflects blue light. Therefore, the red light modulated and emitted by the red light liquid crystal light valve 30R and the blue light modulated and emitted by the blue light liquid crystal light valve 30B are incident on the cross dichroic prism 41, respectively. Reflected by the reflecting surface. Then, the red light and the blue light are combined with the green light that is incident on the cross dichroic prism 41 and passes straight through, and the combined light is emitted as image light.

  The projection optical system 50 is disposed on the exit side of the cross dichroic prism 41, and includes a projection lens unit 51 and a lens shift mechanism (a specific configuration is not shown) for moving the projected image vertically and horizontally. It is configured. The image light emitted from the color synthesizing optical system 40 by the projection lens unit 51 is enlarged and projected onto a projection surface such as a screen.

  Here, the operation of the illumination optical system 10 in the projection display apparatus configured as described above will be described. Note that the color separation optical system 20, the light modulation optical system 30, the color synthesis optical system 40, and the projection optical system 50 have a general configuration as described above, and thus the description of the operation is omitted here.

  The blue light emitted from the blue light emitting diode 11B is collimated by the collimating lens 12B, passes through the first dichroic mirror 13R and the second dichroic mirror 13G, and enters the fly-eye lens 16.

  The red light emitted from the red light emitting diode 11R is collimated by the collimating lens 12R and reflected by the first dichroic mirror 13R. The red light reflected by the first dichroic mirror 13R passes through the second dichroic mirror 13G and enters the fly-eye lens 16.

  Next, the laser emitter 11A has a plurality of blue laser diodes arranged in an array, and the laser light emitted from each blue laser diode passes through the anisotropic diffusion plate 14. It is diffused by the refraction action by the surface structure of the relief hologram pattern. The laser light emitted from the blue laser diode has an initial light emitting surface shape that is substantially circular. However, the laser light has a desired surface shape by transmitting through the anisotropic diffusion plate 14 formed in a predetermined surface structure. Deformed. The laser light that has passed through the anisotropic diffusion plate 14 passes through the second dichroic mirror 13G, and then passes through the collimating lens 12A to be condensed on the surface of the phosphor 15 and applied to the surface of the reflecting mirror. The body 15 is irradiated. The condensing surface shape of the laser light condensed on the surface of the phosphor 15 is deformed into an ellipse by the anisotropic diffusion plate 14, and the short side dimension of the ellipse is allowed to enter the polarizing beam splitter 17. It is diffused and deformed so as to approximate the short side dimension of the surface F (see FIGS. 3B and 4B, which will be described later).

  The phosphor 15 is excited by laser light to emit green light (that is, green fluorescent light). The emitted green light is emitted with a surface shape similar to the shape of the condensing surface of the laser light collected on the surface of the phosphor 15, and is emitted and diffused. The emitted green light is reflected by the reflecting mirror coated with the phosphor 15 and collimated by the collimating lens 12A. The collimated green light is incident on the second dichroic mirror 13G, reflected by the second dichroic mirror 13G, combined with the red light and blue light described above, and applied to the fly-eye lens 16.

  In the above, the laser light focused on the phosphor 15 is diffused rather than the light emitting surface shape as it is emitted from the blue laser diode, so that the light density is reduced. Therefore, the temperature rise of the phosphor 15 is mitigated as compared with the case where the phosphor 15 is irradiated with the condensing surface shape as it is emitted from the blue laser diode.

  The illumination light including blue light in the blue light region, red light in the red light region, and green light in the green light region incident on the fly-eye lens 16 is arranged in a grid pattern in the first lens array 16a. Each of the lenses is once divided into a grid pattern, and then condensed onto the cell lens of the second lens array 16b corresponding to the cell lens of the first lens array 16a. Condensing light onto the cell lens of the second lens array 16b as described above means that the polarization beam splitter 17 is disposed close to the fly-eye lens 16, and therefore the entrance allowable surface of the polarization beam splitter 17 It is almost synonymous with being focused on F. Then, the light condensed on the cell lens in this way is taken into the polarization beam splitter 17 from the incidence allowable surface F of the polarization beam splitter 17.

  Further, the condensing surface shape of each color light constituting the irradiation light condensed on the incident allowable surface F of the polarization beam splitter 17 is incident in a surface shape at the time of light emission. That is, the green light is incident on the surface of the phosphor 15 in the shape of a condensing surface of the laser light that is condensed. Therefore, the shape of the condensing surface of the laser beam condensed on the surface of the phosphor 15 becomes a substantially circular shape when diffused by the isotropic diffusing plate. In the present invention, however, the anisotropic diffusing plate 14 While being deformed into an ellipse, the ellipse is deformed so that the short side dimension of the ellipse approximates the short side dimension of the incidence allowable surface F of the polarization beam splitter 17.

  3 and 4 are diagrams for explaining the meaning of the diffusion deformation. If the condensing surface shape E of the green light collected on the incident allowable surface F of the polarizing beam splitter 17 remains substantially circular, the incident allowable surface F of the polarizing beam splitter 17 is a rectangular rectangle. The light utilization efficiency decreases or the diffusion angle cannot be increased.

  This point will be described more specifically. As shown in FIGS. 3 (a) and 4 (a), the circular diameter, which is the condensing surface shape E of the green light condensed on the incident allowable surface F of the polarization beam splitter 17, is emphasized with respect to the diffusion angle. If the light is diffused, a light flux that is not captured in the short side direction of the incidence allowable surface F is generated, and the light use efficiency may be reduced. On the other hand, in order to avoid the generation of such a light beam that is not captured, when the diameter of the circular shape of the condensing surface shape E is adjusted to the short side dimension of the incidence allowable surface F of the polarizing beam splitter 17, the condensing surface shape E is changed. The diffusion angle must be reduced and the diffusion angle cannot be increased.

  On the other hand, in the case of the present embodiment, as shown in FIGS. 3B and 4B, the condensing surface shape E of the green light condensed on the incident allowable surface F of the polarization beam splitter 17 is illustrated. And the elliptical short side dimension is diffused and deformed so as to approximate the short side dimension of the incidence allowable surface F of the polarization beam splitter 17. Therefore, the diffusion angle can be increased, and the generation of a light beam that is not taken into the rectangular incident portion in the optical system located at the rear stage of the light source, that is, the incidence allowable surface F of the polarization beam splitter 17 can be greatly reduced. . This also improves the light utilization efficiency.

Next, effects according to the embodiment of the present invention configured as described above will be described.
(1) Since the laser light irradiated on the surface of the phosphor 15 is diffused, the light density of the laser light irradiated portion on the surface of the phosphor 15 is reduced, and the temperature rise of the laser light irradiated portion on the surface is suppressed. The Thereby, the luminous efficiency of the phosphor 15 can be improved.

  (2) Since the anisotropic diffusion plate 14 is used as the diffusion plate, the condensing surface shape of the laser light condensed on the surface of the phosphor 15 is an ellipse, and the short side dimension of the ellipse is Can be diffused and deformed in a state that approximates the short side dimension of the rectangular incident portion (in this embodiment, the incidence allowable surface F of the polarization beam splitter 17) in the subsequent optical system. As a result, the amount of light that is not taken into the subsequent optical system can be reduced, and the light utilization efficiency can be improved.

  (3) As a light source for red light and a light source for blue light that can easily obtain a desired high output even by a light emitting diode, inexpensive light emitting diodes are used. On the other hand, a laser light emitter 11A is used as a light source for green light, which is difficult to obtain a desired high output with a light emitting diode, and laser light emitted from the laser light emitter 11A is irradiated to the phosphor 15 as excitation light. Green fluorescent light emitted from the phosphor 15 is used as green light. Accordingly, it is possible to obtain a light source with sufficient output while giving priority to the use of the light emitting diode and limiting the use of the laser emitter 11A.

  (4) In the projection display apparatus using the fly-eye lens 16 and the polarization beam splitter 17 as in the projection display apparatus according to the present embodiment, the surface of the second lens array 16b of the fly-eye lens 16 Fluorescent light is collected on the surface. Further, this condensing position is substantially the incident portion of the polarizing beam splitter 17, which becomes the strip-shaped incident allowable surface F of the polarizing beam splitter 17. Therefore, the condensing surface shape of the laser light condensed and irradiated on the surface of the phosphor 15 is diffused and deformed into an ellipse by the anisotropic diffusion plate 14, and the short side dimension of the ellipse is changed into a polarized beam. The splitter 17 is deformed so as to approximate the short side dimension of the strip-shaped entrance allowable surface F. Thereby, light can be efficiently taken in from the incidence allowable surface F of the polarization beam splitter 17, and the utilization efficiency of light can be improved.

  (5) The projection display apparatus according to the present embodiment is a three-plate projection display apparatus using a liquid crystal panel as a light modulation device, and a laser emitter 11A as a part of the light source of the illumination optical system 10. Therefore, it is possible to provide a three-plate projection image display apparatus having a light source that has a long life, does not require a high voltage, and emits light with high efficiency.

(Embodiment 2)
Next, a projection display apparatus according to Embodiment 2 will be described with reference to FIG.

  The projection display apparatus according to the second embodiment is a projection display apparatus in which the illumination optical system in the first embodiment is used and a reflection display element composed of a micromirror element is used as a light modulation element. It is.

  The projection display apparatus of FIG. 5 includes an illumination optical system 110 having the same configuration as that of the first embodiment, a guide optical system 120 that guides a light beam emitted from the illumination optical system 110 to the light modulation optical system 130, and a guide. It comprises a light modulation optical system 130 that optically modulates a light beam guided to the optical system 120, and a projection optical system 140 that enlarges and projects the light-modulated image light.

  The illumination optical system 110 uses a blue light emitting diode (LED) 111B as in the illumination optical system 10 in the first embodiment, and a red light emitting diode (LED) 111R as a red light source. Further, the illumination optical system 110 uses a light source that emits green light by exciting the phosphor 115 by irradiating the phosphor 115 with laser light emitted from the laser emitter 111A as a green light source. In this configuration, the configurations of the blue light emitting diode 111B and the red light emitting diode 111R, the laser light emitter 111A, and the phosphor 115 are the same as the blue light emitting diode 11B and the red light emitting diode 11R, the laser light emitter 11A, and the phosphor 15 in the first embodiment. Are the same.

  The illumination optical system 110 includes a first dichroic mirror 113R, a second dichroic mirror 113G, and collimating lenses 112B and 112R as devices other than those described above for emitting blue light and red light. These devices are the same as the first dichroic mirror 13R, the second dichroic mirror 13G, and the collimating lenses 12B and 12R in the first embodiment, and are arranged in the same manner as in the first embodiment.

  The illumination optical system 110 is provided with an anisotropic diffuser 114, a phosphor 115, and a collimator lens 112A as devices other than those described above for generating green light. This is the same as the anisotropic diffusion plate 14, phosphor 15 and collimating lens 12A in the first embodiment. Therefore, the configuration of the light source in the illumination optical system 110 is the same as that in the first embodiment. However, unlike the illumination optical system 10 in Embodiment 1, each light source in the illumination optical system 110 is controlled to emit light in a time division manner.

  In the illumination optical system 110 according to the second embodiment, the fly-eye lens 16 and the polarization beam splitter 17 according to the first embodiment are not used. As an alternative device, the light is emitted via the second dichroic mirror 113G. A condenser lens 116 for collecting the collected light and a light guide member 117 having a rectangular cross section for introducing the collected light are provided. The light guide member 117 makes the luminance distribution of the illumination light collected by the condenser lens 116 uniform. In this embodiment, a rod integrator made of a square bar such as glass is used. .

  The guide optical system 120 is configured to guide the light emitted from the illumination optical system 110 to the light modulation optical system 130, and includes devices such as relay lenses 121 and 123 and a total reflection mirror 122. Has been.

  The light modulation optical system 130 uses a reflective display element 131 and an absorber 132, which are generally abbreviated as DMD (Digital Micromirror Device), and performs digital light modulation.

  The reflective display element 131 is a semiconductor integrated optical switch having a structure in which about 500,000 to 1.3 million micromirror elements are spread in a matrix, so that the pixels in the image frame correspond to the micromirror elements. It is arranged. In addition, the micromirror element in the reflective display element 131 is attached to the support so that the inclination changes about ± 10 degrees in the on and off states. In the on state, the reflective display element 131 reflects light emitted from the guide optical system by the micromirror element and is emitted toward the projection optical system. In the off state, the reflective display element 131 reflects from the micromirror element. The reflected light is reflected so as to be absorbed by the absorber 132. The absorber 132 is arranged in a direction inclined about 20 degrees from the light beam in the on state.

  The reflective display element 131 configured as described above is turned on / off in synchronization with blue light, red light, and green light sequentially time-divided from the illumination optical system 110 and has a switching ratio. Optical modulation is performed by so-called PWM control.

  The projection optical system 140 includes a projection lens that enlarges and projects the image light reflected when the reflective display element 131 is turned on onto a projection surface such as a screen. Is the same.

  Next, the operation of the illumination optical system 110 according to Embodiment 2 configured as described above will be described. Since the guide optical system 120, the light modulation optical system 130, and the projection optical system 140 are general as described above, description of the operation of these optical systems is omitted here.

  In this embodiment, the blue light and the red light are emitted from the blue light emitting diode 111B and the red light emitting diode 111R as in the case of the first embodiment, and the collimating lens 112B, the collimating lens 112R, the first dichroic mirror 113R, and the first light emitting diode 111R. The light is emitted toward the condenser lens 116 via the two-dichroic mirror 113G.

  Similarly to the first embodiment, green light is emitted to phosphor 115 using blue laser light from laser emitter 111A as excitation light, and green fluorescent light is emitted from phosphor 115 as green light. Is done. The emitted green light is reflected by the reflecting mirror coated with the phosphor 15, and further collimated by the collimating lens 12A and emitted to the second dichroic mirror 13G. The green light is reflected by the second dichroic mirror 13G and emitted toward the condenser lens 116.

  In the green light emission process, the blue laser light emitted from the laser emitter 111A is diffused while being deformed to have a predetermined surface shape by the anisotropic diffusion plate 114. More specifically, the condensing surface shape of the blue laser light condensed on the surface of the phosphor 115 is deformed into an ellipse, and the short side dimension of the ellipse is a rectangular incident surface of the light guide member 117. Is diffused and deformed so as to approximate the short side dimension. Further, since the blue laser light is diffused and deformed in this manner, the temperature rise on the surface of the phosphor 115 is suppressed, and the light emission efficiency in the phosphor 115 is improved. The rectangular incident surface of the light guide member 117 is a rectangular incident portion in the optical system located at the rear stage of the light source.

  Blue light, red light, and green light emitted as described above are controlled by a control unit (not shown), and are sequentially emitted in a time-division manner. Each color light sequentially emitted is condensed by the condenser lens 116 on an incident surface as a rectangular incident portion of the light guide member 117. In this case, the shape of the condensing surface of the green light collected on the incident surface of the light guide member 117 is deformed into an ellipse, and the short side dimension of the ellipse is shorter than the incident surface of the light guide member 117. Since the anisotropic diffusion plate 114 is set so as to approximate the side dimension, the light that is not taken into the light guide member 117 can be reduced, and the utilization efficiency of green light is improved.

  Then, each color light condensed on the incident surface of the light guide member 117 enters the light guide member 117. Each incident color light is repeatedly reflected in the light guide member 117 to make the luminance distribution uniform. The light emitted in this way as light having a uniform luminance distribution is guided to the guide optical system 120. As described above, the guide optical system 120, the light modulation optical system 130, and the projection optical system 140 have a conventionally known general configuration, and each color light guided from the guide optical system 120 to the light modulation optical system 130 is a conventional one. As is well known, it is modulated and projected as image light by the projection optical system 140.

  Since the projection display apparatus according to Embodiment 2 is configured as described above, in addition to the effects (1) to (3) and (5) in Embodiment 1, the following effects can be obtained. Can do.

  (6) The projection display apparatus according to the second embodiment uses a rod-shaped or cylindrical light guide member 117 having a rectangular incident surface, but the anisotropic diffusion plate 114 causes the phosphor 115 to be on the surface. The condensing surface shape of the laser beam to be condensed is an ellipse, and the elliptical short side dimension is diffused and deformed to approximate the short side dimension of the incident surface of the light guide member 117. Thereby, light can be efficiently taken into the light guide member 117, and the light use efficiency can be improved.

  (7) The projection display apparatus according to Embodiment 2 is a projection display apparatus that uses a reflective display element composed of a micromirror element as a light modulation device, and is a partial light source of the illumination optical system 110. Since the laser emitter 111A is used, a projection display apparatus having a light source that has a long life, does not require a high voltage, and emits light with high efficiency can be provided.

(Modification)
The present invention can be modified as follows in the above embodiment.
In each of the above embodiments, the anisotropic diffusion plates 14 and 114 are used as the diffusion plate, but an isotropic diffusion plate having the same diffusion angle in any direction may be used.

  In each of the above embodiments, laser light is used only when green light is obtained. However, a diffusion plate is also used when laser light is used as excitation light for obtaining other color light. Thus, the luminous efficiency can be improved. Also in this case, the use efficiency of light may be improved by using the anisotropic diffusion plates 14 and 114 so that light is efficiently taken into the optical system at the subsequent stage.

  In each of the above embodiments, a blue laser diode that outputs laser light in the blue wavelength region is used to generate green light. However, this laser diode may be an ultraviolet laser diode that outputs ultraviolet light. .

  In each of the above embodiments, the phosphors 15 and 115 are irradiated with the laser beam that is the excitation light. However, these may be phosphors that emit phosphorescence. The two are not distinguished from each other in practice, and may be called a phosphor or simply a phosphor, and the present invention encompasses these.

  In the second embodiment, a rod-shaped rod integrator having a rectangular incident surface is used as the light guide member 117. Instead, the incident portion is a rectangular incident surface, and the inner surface is formed of a mirror. A cylindrical light tunnel may be used. In this case, the shape of the condensing surface of the laser light condensed on the surface of the phosphor 115 may be approximated to the shape of the rectangular incident portion of the light tunnel (that is, the entrance of the light tunnel).

  The type of the projection display apparatus is not limited to that of the above embodiment. For example, a projection-type image display device using a reflective liquid crystal panel can be used.

  The projection display apparatus according to the present invention can be used as an image display system in various facilities such as a home theater, a conference room, a training room, a classroom, an amusement hall, various exhibition rooms, and a studio.

  E ... Condensation surface shape (fluorescent light or phosphorescent light), F ... Incident acceptance surface (of polarization beam splitter), 10, 110 ... Illumination optical system, 11A, 111A ... Laser emitter, 11B, 111B ... Blue light emitting diode , 11R, 111R ... red light emitting diode, 14, 114 ... anisotropic diffusion plate, 15, 115 ... phosphor, 16 ... fly-eye lens, 17 ... polarization beam splitter, 117 ... light guide member, 131 ... reflective display element .

Claims (7)

An illumination optical system that emits fluorescent light or phosphorescent light by irradiating the fluorescent material or phosphor with laser light as excitation light from a laser emitter, and uses the fluorescent light or phosphorescent light as illumination light of at least a part of colored light A projection display device comprising:
In the illumination optical system, a diffusion plate is provided between the laser emitter and the phosphor or phosphor, and the laser light from the laser emitter passes through the diffusion plate to irradiate the phosphor or phosphor. A projection-type image display device characterized by comprising: The projection display apparatus according to claim 1, wherein
By making the diffuser plate an anisotropic diffuser plate, the condensing surface shape of the laser beam condensed on the surface of the phosphor or phosphor is made elliptical, and the short side dimension of this elliptical is the optical length of the latter stage. A projection-type image display apparatus, characterized in that it approximates the short side dimension of a rectangular incident portion on which the fluorescent light or phosphorescent light is collected and incident in the system. The projection display apparatus according to claim 2, wherein
The illumination optical system includes a light source for red light, a light source for blue light, and a light source for green light. Among these light sources, the light source for red light is composed of a red light emitting diode, and the light source for blue light is composed of a blue light emitting diode. The green light source uses the green fluorescent light or phosphorescent light emitted from the phosphor or phosphor by irradiating the phosphor or phosphor with the laser light from the laser emitter as excitation light. A projection-type image display device characterized by comprising: The projection display apparatus according to claim 2 or 3,
The illumination optical system uses a fly-eye lens and a polarizing beam splitter, and is configured such that an incident permissible surface forming a strip shape of the polarizing beam splitter is the rectangular incident portion. Projection-type image display device. The projection display apparatus according to claim 2 or 3,
The illumination optical system includes a rod-shaped or cylindrical light guide member having an incident surface formed in a rectangular shape, and the incident surface of the light guide member is configured to be the rectangular incident portion. A projection-type image display device characterized by that. The projection display apparatus according to claim 4, wherein
A projection-type image display device, characterized in that it is formed in a three-plate projection-type image display device that uses a red light liquid crystal panel, a green light liquid crystal panel, and a blue light liquid crystal panel as the light modulation device. The projection display apparatus according to claim 5, wherein
A projection-type image display device, characterized in that it is formed in a projection-type image display device using a reflection-type display element comprising a micromirror element as a light modulation device.