JP5066802B2 - projector - Google Patents

Description

  The present invention relates to a projector.

  2. Description of the Related Art Conventionally, as a projector, a projector having a cross dichroic prism that synthesizes each color light modulated by three electro-optic modulators, and a translucent member bonded to each light incident end face of the cross dichroic prism via an adhesive layer Is known (for example, see Patent Document 1). Each electro-optic modulator has a liquid crystal panel, an incident side polarizing plate, and an exit side polarizing plate, and the exit side polarizing plate is bonded to the light incident side surface of the translucent member.

  According to the conventional projector, the heat generated in the exit side polarizing plate is dissipated through the translucent member to the cross dichroic prism having a large heat capacity, thereby suppressing the temperature rise of the exit side polarizing plate. Is possible. For this reason, it becomes possible to suppress that the polarization | polarized-light characteristic of an exit side polarizing plate deteriorates by the exit side polarizing plate, and it can suppress that the image quality of a projection image falls as a result. It becomes.

JP 2002-244214 A

  By the way, in recent years, an opportunity to use a projector for an application such as a home theater is increasing, and there is an increasing demand for further improving the image quality of a projected image.

  Accordingly, the present invention has been made in view of such circumstances, and an object thereof is to provide a projector capable of further improving the image quality of a projected image.

  In order to achieve the above object, the inventors of the present invention have conducted a thorough investigation and research on the cause of the deterioration of the image quality of the projected image in the conventional projector. As a result, the conventional projector has the following problems. Turned out to be.

  FIG. 4 is a diagram for explaining a problem in the conventional projector. 4A is a conceptual diagram showing a locus of a certain ray of green light incident on the cross dichroic prism 950, and FIG. 4B is a ray of red light and blue light incident on the cross dichroic prism 950. It is a conceptual diagram which shows the locus | trajectory.

In a conventional projector, a condensing lens or the like is disposed in front of the optical path of the electro-optic modulator, so that light incident on the liquid crystal panel of the electro-optic modulator is perpendicular to the liquid crystal panel surface (with respect to the illumination optical axis). However, since it is not easy to make all of the incident light perpendicular to the liquid crystal panel surface, some incident light has a constant incident angle (in this case, The incident angle is an acute angle) and enters the liquid crystal panel. Light incident on the liquid crystal panel at a constant incident angle passes through the liquid crystal panel and is incident on the cross dichroic prism at the same constant incident angle.
As described above, when there is light incident on the cross dichroic prism at a constant incident angle, there are the following problems.

For example, as shown in FIG. 4A, the light L ₁ and L ₂ incident at a constant incident angle with respect to the green light emission end face S ₂ in the cross dichroic prism 950 are not the light emission end face S _4. the sub-routine proceeds toward the light incident end face S ₃ of the light incident end surface of the red light S ₁ or blue light. At this time, in the conventional projector, an adhesive having a refractive index smaller than the refractive index of the cross dichroic prism 950 is used as the material of the adhesive layers 960R and 960B, so that the lights L ₁ and L ₂ are cross dichroic prisms. There is a possibility of total reflection at the interface between 950 and the adhesive layers 960R and 960B.

Further, as shown in FIG. 4B, the light L ₃ incident at a constant incident angle on the light incident surface S ₁ of red light in the cross dichroic prism 950 is reflected by the dielectric multilayer film 952. Therefore, it proceeds toward the light incident end surface S ₁ of red light instead of the light emitting end surface S ₄ . At this time, the refractive index of the adhesive layer 960R is smaller than the refractive index of the cross dichroic prism 950, the light L ₃ may possibly be totally reflected at the interface between the adhesive layer 960R and the cross dichroic prism 950.

Further, as shown in FIG. 4B, the light L ₄ incident on the light incident surface S ₃ of blue light in the cross dichroic prism 950 at a constant incident angle is reflected by the dielectric multilayer film 954. , the sub-routine proceeds toward the light incident end face S ₃ of the light-emitting end face S ₄ without blue light. At this time, the refractive index of the adhesive layer 960B is smaller than the refractive index of the cross dichroic prism 950, light L ₄ represents there is a possibility that is totally reflected at the interface between the adhesive layer 960B and the cross dichroic prism 950.

When these lights L _{1 to} L ₄ are emitted from the light exit end face S ₄ of the cross dichroic prism 950, they become stray light and are projected on the projection surface, so that the image quality of the projected image is deteriorated.

  As described above, in the conventional projector, there is light incident on the cross dichroic prism at a constant incident angle, and such light is totally reflected at the interface between the cross dichroic prism and the adhesive layer. As a result, there has been a problem that the image quality of the projected image is degraded.

  Therefore, the inventors of the present invention based on the above knowledge, even if there is light incident at a constant incident angle on the cross dichroic prism as in the conventional projector, such light By suppressing the total reflection at the interface between the cross dichroic prism and the adhesive layer, it has been conceived that the image quality of the projected image can be further improved, and the present invention has been completed.

  That is, the projector according to the present invention includes an illuminating device that emits an illuminating light beam toward the illuminated region, three electro-optic modulators that modulate the illuminating light beam from the illuminating device according to image information, and the three electric devices. A cross dichroic prism having three light incident end faces that respectively receive the three color lights modulated by the optical modulator and a light exit end face that emits the combined color light, and a projection optical system that projects the light from the cross dichroic prism And three translucent members respectively bonded to the three light incident end faces of the cross dichroic prism via an adhesive layer, wherein the refractive index of the adhesive layer is determined by the cross dichroic prism. It is characterized by being larger than the refractive index.

  Therefore, according to the projector of the present invention, since the refractive index of the adhesive layer is larger than the refractive index of the cross dichroic prism, there is light incident on the cross dichroic prism at a constant incident angle as in the conventional projector. Even in this case, it is possible to prevent such light from being totally reflected at the interface between the cross dichroic prism and the adhesive layer. As a result, it is possible to suppress stray light from being projected on the projection surface, and it is possible to suppress deterioration in image quality of the projected image.

  Therefore, the projector of the present invention is a projector that can further improve the image quality of the projected image.

  In the projector according to the aspect of the invention, it is preferable that a refractive index of the adhesive layer is smaller than a refractive index of the translucent member.

  With this configuration, even when there is light incident on the cross dichroic prism at a constant incident angle as in a conventional projector, such light is transmitted between the cross dichroic prism and the adhesive layer. In addition to being able to suppress total reflection at the interface, it is possible to prevent light that has passed through the adhesive layer from being totally reflected at the interface between the adhesive layer and the translucent member. It becomes possible. As a result, it is possible to further suppress the stray light from being projected on the projection surface, and to further suppress the deterioration of the image quality of the projected image.

  In the projector according to the aspect of the invention, it is preferable that a light shielding member is disposed around the light exit end face of the cross dichroic prism.

  By configuring in this way, the adhesive layer is incident on the cross dichroic prism at a constant incident angle and is not totally reflected at the interface between the cross dichroic prism and the adhesive layer or the interface between the adhesive layer and the translucent member. And light passing through the translucent member can be shielded by the light shielding member disposed around the light emitting end face, so that projection of stray light on the projection surface can be further suppressed, and the image of the projected image can be suppressed. It becomes possible to further suppress deterioration in quality.

  The light shielding member is preferably a member that absorbs light.

  In the projector according to the aspect of the invention, the electro-optic modulation device includes a liquid crystal panel that modulates each of a plurality of color lights according to image information, an incident-side polarizing plate disposed on a light incident side of the liquid crystal panel, and the liquid crystal It is an electro-optic modulation device having an emission side polarizing plate disposed on the light emission side of the panel, and the emission side polarizing plate is preferably bonded to the light incident side surface of the translucent member. .

  The emission-side polarizing plate has a function of transmitting only linearly polarized light having an axis in a predetermined direction out of light emitted from the liquid crystal panel and absorbing other light, and generates heat when absorbing light. If the temperature of the exit-side polarizing plate rises above a predetermined temperature due to this heat generation, the exit-side polarizing plate may be deteriorated. When the exit side polarizing plate deteriorates, the polarization characteristics of the exit side polarizing plate decrease, resulting in a decrease in the image quality of the projected image, such as a decrease in contrast of the projected image or unevenness of color or color. End up.

  However, according to the projector of the present invention, since the exit side polarizing plate is bonded to the light incident side surface of the translucent member, the heat generated by the exit side polarizing plate has a heat capacity through the translucent member. Dissipates into a large cross dichroic prism. For this reason, it becomes possible to suppress the temperature rise of the exit side polarizing plate, and it is possible to suppress the deterioration of the polarization characteristics of the exit side polarizing plate due to the deterioration of the exit side polarizing plate. As a result, it is possible to suppress degradation of the image quality of the projected image.

  In the projector according to the aspect of the invention, it is preferable that the translucent member is made of sapphire or crystal.

When the translucent member is made of sapphire or quartz, these materials are extremely excellent in thermal conductivity, so the heat generated by the exit side polarizing plate can be efficiently dissipated outside the system, It is possible to effectively suppress the temperature rise of the side polarizing plate.
In addition, as a translucent member, when importance is attached to cheapness, white plate glass can also be used.

  In the projector according to the aspect of the invention, the projector may further include a housing that houses each optical system, and a heat conduction member that transfers heat between at least one of the three translucent members and the housing. Is preferred.

  With this configuration, the heat generated by the exit-side polarizing plate is dissipated to the housing via the translucent member and the heat conducting member, so that the heat dissipation performance of the projector can be improved.

  The heat conducting member is preferably made of metal.

  In the projector according to the aspect of the invention, it is preferable that a cooling air flow path for cooling the three translucent members is provided.

  By comprising in this way, since the exit side polarizing plate can be cooled with the cooling air from the cooling air flow path, the temperature rise of the exit side polarizing plate is suppressed, and the heat generated in the exit side polarizing plate is efficiently generated. Can be removed.

  The projector of the present invention will be described below based on the embodiments shown in the drawings.

[Embodiment]
FIG. 1 is a diagram illustrating an optical system of a projector 1000 according to the embodiment. FIG. 2 is a diagram for explaining a main part of the projector 1000 according to the embodiment. 2A is a view of the peripheral portion of the cross dichroic prism 500 as viewed from above, and FIG. 2B is a cross-sectional view taken along line AA of FIG. 2A.

  As shown in FIG. 1, the projector 1000 according to the embodiment separates the illumination device 100 and the illumination light flux from the illumination device 100 into three color lights of red light, green light, and blue light and guides them to the illuminated area. Color separation light guide optical system 200, three electro-optic modulation devices 400R, 400G, and 400B that modulate each of the three color lights separated by the color separation light guide optical system 200 according to image information, and three electrical A cross dichroic prism 500 that synthesizes each color light modulated by the optical modulators 400R, 400G, and 400B, and a projection optical system 600 that projects the light synthesized by the cross dichroic prism 500 onto a projection surface such as a screen SCR. It is a projector. Each of these optical systems is housed in a housing 10.

  The illuminating device 100 includes a light source device 110 as a light source that emits an illumination light beam that is substantially parallel to the illuminated region side, and a plurality of first small light beams that are used to divide the illumination light beam emitted from the light source device 110 into a plurality of partial light beams. The light source device 110 emits the first lens array 120 having the lenses 122, the second lens array 130 having the plurality of second small lenses 132 corresponding to the plurality of first small lenses 122 of the first lens array 120, and the light source device 110. It has a polarization conversion element 140 that aligns illumination light beams whose polarization directions are not aligned to approximately one type of linearly polarized light, and a superimposing lens 150 for superimposing each partial light beam emitted from the polarization conversion element 140 in the illuminated area. ing.

  The light source device 110 includes an ellipsoidal reflector 114, an arc tube 112 having a light emission center near the first focal point of the ellipsoidal reflector 114, an auxiliary mirror 116 having a reflecting surface facing the reflecting surface of the ellipsoidal reflector 114, an ellipse And a concave lens 118 that converts the focused light reflected by the surface reflector 114 into substantially parallel light and emits the light toward the first lens array 120. The light source device 110 emits a light beam having the illumination optical axis 100ax as a central axis.

The arc tube 112 has a tube bulb portion and a pair of sealing portions extending on both sides of the tube bulb portion.
The ellipsoidal reflector 114 includes a cylindrical neck that is inserted and fixed to one sealing portion of the arc tube 112, and a reflective concave surface that reflects light emitted from the arc tube 112 toward the second focal position. have.

  The auxiliary mirror 116 is provided facing the ellipsoidal reflector 114 with the tube bulb portion of the arc tube 112 interposed therebetween, and returns light that has not been directed to the ellipsoidal reflector 114 out of the light emitted from the arc tube 112 to the arc tube 112. The light is incident on the ellipsoidal reflector 114.

  The concave lens 118 is disposed on the illuminated area side of the ellipsoidal reflector 114. Then, the light from the ellipsoidal reflector 114 is emitted toward the first lens array 120.

  The first lens array 120 has a function as a light beam splitting optical element that splits light from the concave lens 118 into a plurality of partial light beams, and a plurality of first lens arrays 120 arranged in a matrix in a plane orthogonal to the illumination optical axis 100ax. It has a configuration provided with one small lens 122.

  The second lens array 130 is an optical element that collects a plurality of partial light beams divided by the first lens array 120, and in the same manner as the first lens array 120, in a matrix form in a plane orthogonal to the illumination optical axis 100ax. It has the structure provided with the some 2nd small lens 132 arranged.

The polarization conversion element 140 is a polarization conversion element that emits the polarization direction of each partial light beam divided by the first lens array 120 as approximately one type of linearly polarized light having a uniform polarization direction.
The polarization conversion element 140 transmits the illumination light beam related to one linear polarization component among the polarization components included in each partial light beam from the second lens array 130 and reflects the illumination light beam related to the other linear polarization component. A reflection layer that reflects the illumination light beam related to the other linearly polarized light component reflected by the polarization separation layer in a direction substantially parallel to the illumination optical axis 100ax, and one linear polarization component that has passed through the polarization separation layer. A retardation plate disposed in a portion through which the illumination light beam passes.

  The superimposing lens 150 condenses a plurality of partial light beams that have passed through the first lens array 120, the second lens array 130, and the polarization conversion element 140, and the liquid crystal panels 410R, 410G, 410B in the electro-optic modulation devices 400R, 400G, 400B. It is an optical element for making it superimpose on the image formation area vicinity. The superimposing lens 150 shown in FIG. 1 is composed of a single lens, but may be composed of a compound lens in which a plurality of lenses are combined.

  The color separation light guide optical system 200 includes a first dichroic mirror 210 and a second dichroic mirror 220, reflection mirrors 230, 240, 250, an incident side lens 260, and a relay lens 270. The color separation light guide optical system 200 separates the illumination light beam emitted from the superimposing lens 150 into three color lights of red light, green light, and blue light, and the three liquid crystal panels 410R that are the illumination targets. , 410G, 410B.

  The first dichroic mirror 210 and the second dichroic mirror 220 are optical elements on which a wavelength selection film that reflects a light beam in a predetermined wavelength region and transmits a light beam in another wavelength region is formed on a substrate. The first dichroic mirror 210 is a mirror that reflects a red light component and transmits other color light components. The second dichroic mirror 220 is a mirror that reflects the green light component and transmits the blue light component.

  The red light component reflected by the first dichroic mirror 210 is bent by the reflection mirror 230 and enters the image forming area of the liquid crystal panel 410R for red light via the condenser lens 300R.

  The condenser lens 300R is provided to convert each partial light beam from the superimposing lens 150 into a light beam substantially parallel to each principal ray. The condenser lens 300 </ b> R is held by a heat conductive holding member (not shown), and is disposed in the housing 10 through the heat conductive holding member. The condensing lenses 300G and 300B arranged in the preceding stage of the optical path of the other liquid crystal panels 410G and 410B are configured in the same manner as the condensing lens 300R.

  Of the green light component and blue light component transmitted through the first dichroic mirror 210, the green light component is reflected by the second dichroic mirror 220, passes through the condenser lens 300G, and is an image of the liquid crystal panel 410G for green light. Incident into the formation area. On the other hand, the blue light component is transmitted through the second dichroic mirror 220, passes through the incident side lens 260, the incident side reflection mirror 240, the relay lens 270, the emission side reflection mirror 250, and the condenser lens 300B, and is emitted as blue light. Is incident on the image forming area of the liquid crystal panel 410B. The incident side lens 260, the relay lens 270, and the reflection mirrors 240 and 250 have a function of guiding the blue light component transmitted through the second dichroic mirror 220 to the liquid crystal panel 410B.

  The reason that the incident side lens 260, the relay lens 270, and the reflection mirrors 240 and 250 are provided in the optical path of blue light is that the length of the optical path of blue light is longer than the length of the optical paths of other color lights. For this reason, a decrease in light use efficiency due to light divergence or the like is prevented. The projector 1000 according to the embodiment has such a configuration because the length of the optical path of blue light is long, but the length of the optical path of red light is increased so that the incident side lens 260, the relay lens 270, and A configuration in which the reflection mirrors 240 and 250 are used in the optical path of red light is also conceivable.

  As shown in FIGS. 2A and 2B, the electro-optic modulators 400R, 400G, and 400B include liquid crystal panels 410R, 410G, and 410B that modulate each of the three color lights according to image information, and liquid crystal Incident side polarizing plates 430R, 430G, and 430B disposed on the light incident side of the panels 410R, 410G, and 410B, and emission side polarizing plates 450R, 450G, and 450B disposed on the light emitting side of the liquid crystal panels 410R, 410G, and 410B, have.

The liquid crystal panels 410R, 410G, and 410B modulate the illumination light beam according to image information to form a color image, and are the illumination target of the light source device 110.
Each of the liquid crystal panels 410R, 410G, and 410B is obtained by encapsulating a liquid crystal that is an electro-optical material in a pair of transparent glass substrates. For example, incident-side polarization is performed according to a given image signal using a polysilicon TFT as a switching element. The polarization direction of one kind of linearly polarized light emitted from the plates 430R, 430G, and 430B is modulated. Although not shown, the liquid crystal panels 410R, 410G, and 410B are held by a liquid crystal panel holding frame made of, for example, an aluminum die-cast frame.

  The incident-side polarizing plates 430R, 430G, and 430B are disposed between the condenser lenses 300R, 300G, and 300B and the liquid crystal panels 410R, 410G, and 410B. Of the light emitted from the condenser lenses 300R, 300G, and 300B, It has a function of transmitting only linearly polarized light having an axis in a predetermined direction and absorbing other light. The incident side polarizing plates 430R, 430G, and 430B are attached to the light incident surfaces of the translucent members 420R, 420G, and 420B, respectively.

  The translucent members 420R, 420G, and 420B are made of, for example, sapphire. Sapphire has a high thermal conductivity of about 40 W / (m · K), a very high hardness, a low coefficient of thermal expansion, and is hardly scratched and highly transparent. In the case of medium luminance, a quartz substrate having a thermal conductivity of about 10 W / (m · K) can be used instead of sapphire. Moreover, when importance is attached to low cost, white plate glass can also be used.

  The exit-side polarizing plates 450R, 450G, and 450B are disposed between the liquid crystal panels 410R, 410G, and 410B and the cross dichroic prism 500, and the light is emitted from the liquid crystal panels 410R, 410G, and 410B in the predetermined direction. It has a function of transmitting only linearly polarized light having light and absorbing other light. The exit-side polarizing plates 450R, 450G, and 450B are attached to the light incident surfaces of the translucent members 440R, 440G, and 440B, respectively.

The translucent members 440R, 440G, and 440B are bonded to the three light incident end surfaces S ₁ , S ₂ , and S ₃ of the cross dichroic prism 500 via adhesive layers 460R, 460G, and 460B, respectively. The translucent members 440R, 400G, and 400B are made of, for example, sapphire, similar to the translucent members 420R, 420G, and 420B.

  The incident side polarizing plates 430R, 430G, and 430B and the exit side polarizing plates 450R, 450G, and 450B are set and arranged so that the directions of the polarization axes thereof are orthogonal to each other.

The cross dichroic prism 500 is an optical element that forms a color image by synthesizing an optical image modulated for each color light emitted from each of the liquid crystal panels 410R, 410G, and 410B. The cross dichroic prism 500 includes three light incident end faces S ₁ , S ₂ , S ₃ for receiving the color lights modulated by the liquid crystal panels 410R, 410G, 410B, and a light emission end face S ₄ for emitting the combined color lights. have. The cross dichroic prism 500 has a substantially square shape in plan view in which four right-angle prisms are bonded together, and dielectric multilayer films 502 and 504 (FIG. a) is formed). The dielectric multilayer film 502 formed at one interface having a substantially X shape reflects red light, and the dielectric multilayer film 504 formed at the other interface reflects blue light. . By these dielectric multilayer films, the red light and the blue light are bent and aligned with the traveling direction of the green light, so that the three color lights are synthesized.
The cross dichroic prism 500 is disposed in the housing 10 via a thermally conductive spacer 12 (see FIG. 2B).

  The color image emitted from the cross dichroic prism 500 is enlarged and projected by the projection optical system 600 to form a large screen image on the screen SCR.

  In the projector 1000 according to the embodiment, as a material of the adhesive layers 460R, 460G, and 460B, an adhesive having a refractive index that is larger than the refractive index of the cross dichroic prism 500 and smaller than the refractive index of the translucent members 440R, 440G, and 440B. The agent is used. Hereinafter, the effect of the projector 1000 according to the embodiment will be described with reference to FIG.

  FIG. 3 is a diagram for explaining the effect of the projector 1000 according to the embodiment. FIG. 3A is a conceptual diagram showing a locus of a ray of green light incident on the cross dichroic prism 500, and FIG. 3B is a ray of red light and blue light incident on the cross dichroic prism 500. It is a conceptual diagram which shows the locus | trajectory.

In the projector 1000 according to the embodiment, as shown in FIGS. 3A and 3B, there are lights L _{1 to} L ₄ that are incident on the cross dichroic prism 500 at a constant incident angle.

For example, as shown in FIG. 3A, the light L ₁ and L ₂ incident at a constant incident angle with respect to the light emitting end surface S ₂ of green light in the cross dichroic prism 500 are not the light emitting end surface S _4. the sub-routine proceeds toward the light incident end face S ₃ of the light incident end surface of the red light S ₁ or blue light. At this time, since the refractive indexes of the adhesive layers 460R and 460B are larger than the refractive index of the cross dichroic prism 500, the lights L ₁ and L ₂ are not totally reflected at the interface between the cross dichroic prism 500 and the adhesive layers 460R and 460B. It will pass through the adhesive layers 460R and 460B. Further, since the refractive index of the adhesive layers 460R and 460B is smaller than the refractive index of the translucent members 440R and 440B, the light L ₁ and L ₂ that have passed through the adhesive layers 460R and 460B are transmitted to the adhesive layers 460R and 460B. The light transmitting members 440R and 440B pass through the light transmitting members 440R and 440B without being totally reflected at the interfaces with the light transmitting members 440R and 440B. Incidentally, the light-transmissive member 440R, the light _L 1 having passed through the 440B, _{L 2} is so that the thus emitted to the projection optical system 600 side, the periphery of the light-emitting end face _{S 4} is disposed is a light blocking member 470 Therefore, these lights L ₁ and L ₂ do not enter the projection optical system 600.

Further, as shown in FIG. 3B, the light L ₃ incident at a constant incident angle on the light incident surface S ₁ of the red light in the cross dichroic prism 500 is reflected by the dielectric multilayer film 502. Therefore, it proceeds toward the light incident end surface S ₁ of red light instead of the light emitting end surface S ₄ . At this time, since the refractive index of the adhesive layer 460R is larger than the refractive index of the cross dichroic prism 500, the light L ₃ is passing through the adhesive layer 460R without being totally reflected at the interface between the adhesive layer 460R and the cross dichroic prism 050 It becomes. Moreover, since the refractive index of the adhesive layer 460R is smaller than the refractive index of the light transmissive member 460R, the light _{L 3} having passed through the adhesive layer 460R is not totally reflected at the interface between the adhesive layer 460R and the transparent member 440R Will pass through the translucent member 440R. Although the light L ₃ having passed through the light-transmissive member 440R becomes that would be emitted to the projection optical system 600 side, since the light blocking member 470 is disposed around the light-emitting end face S _4, the light L ₃ does not enter the projection optical system 600.

Further, as shown in FIG. 3B, the light L ₄ incident on the light incident surface S ₃ of blue light in the cross dichroic prism 500 at a constant incident angle is reflected by the dielectric multilayer film 504. , the sub-routine proceeds toward the light incident end face S ₃ of the light-emitting end face S ₄ without blue light. At this time, since the refractive index of the adhesive layer 460B is larger than the refractive index of the cross dichroic prism 500, light L ₄ it is able to pass through the adhesive layer 460B without being totally reflected at the interface between the adhesive layer 460B and the cross dichroic prism 500 It becomes. Further, since the refractive index of the adhesive layer 460B is smaller than the refractive index of the translucent member 460B, the light L _{4 that} has passed through the adhesive layer 460B is not totally reflected at the interface between the adhesive layer 460B and the translucent member 440B. Will pass through the translucent member 440B. The light L _{4 that} has passed through the translucent member 440B is emitted to the projection optical system 600 side. However, since the light shielding member 470 is disposed around the light emitting end surface S ₄ , this light is transmitted. L ₄ does not enter the projection optical system 600.

As described above, according to the projector 1000 according to the embodiment, since the refractive index of the adhesive layers 460R, 460G, and 460B is larger than the refractive index of the cross dichroic prism 500, it is constant with respect to the cross dichroic prism as in the conventional projector. Even when there are light beams L _{1 to} L ₄ incident at an angle of incidence, such light beams L _{1 to} L ₄ are totally reflected at the interface between the cross dichroic prism 500 and the adhesive layers 460R, 460G, and 460B. Can be suppressed. As a result, it is possible to suppress stray light from being projected on the screen SCR, and it is possible to suppress deterioration in image quality of the projected image.

  Therefore, the projector 1000 according to the embodiment is a projector that can further improve the image quality of the projected image.

Further, in the projector 1000 according to the embodiment, the refractive index of the adhesive layers 460R, 460G, and 460B is smaller than the refractive index of the translucent members 440R, 440G, and 440B, and thus the cross dichroic prism 500 as in the conventional projector. Even when there is light L _{1 to} L ₄ incident at a constant incident angle, such light L _{1 to} L ₄ is an interface between the cross dichroic prism 500 and the adhesive layers 460R, 460G, and 460B. In addition to the fact that it is possible to suppress the total reflection by the light, the light L _{1 to} L ₄ that has passed through the adhesive layers 460R, 460G, and 460B and the light-transmitting member 440R are the adhesive layers 460R, 460G, and 460B. , 440G, 440B, it is possible to suppress total reflection. As a result, it is possible to further suppress the stray light from being projected on the screen SCR, and to further suppress the deterioration of the image quality of the projected image.

In the projector 1000 according to the embodiment, since the light blocking member 470 is disposed around the light-emitting end face S ₄ in the cross dichroic prism 500, is incident at a certain incident angle with respect to the cross dichroic prism 500, the cross dichroic prism The light passing through the adhesive layer and the translucent member without being totally reflected at the interface between the adhesive layer 500 and the adhesive layers 460R, 460G, and 460B and the interface between the adhesive layer and the translucent member is disposed around the light emitting end surface. Since the light can be shielded by the light shielding member, stray light can be further prevented from being projected on the projection surface, and the deterioration of the image quality of the projected image can be further suppressed.
The light shielding member 470 is preferably a member that absorbs light.

  In the projector 1000 according to the embodiment, since the exit side polarizing plates 450R, 450G, and 450B are bonded to the light incident side surfaces of the translucent members 440R, 440G, and 440B, the exit side polarizing plates 450R, 450G, and 450B. The heat generated in the above is dissipated to the cross dichroic prism 500 having a large heat capacity through the translucent members 440R, 440G, and 440B. For this reason, it becomes possible to suppress the temperature rise of the exit side polarizers 450R, 450G, and 450B, and the exit side polarizers 450R, 450G, and 450B deteriorate and the polarization characteristics of the exit side polarizers 450R, 450G, and 450B decrease. It is possible to suppress this. As a result, it is possible to suppress degradation of the image quality of the projected image.

  In projector 1000 according to the embodiment, translucent members 440R, 440G, and 440B are made of sapphire. Since sapphire is very excellent in thermal conductivity, the heat generated by the exit side polarizing plates 450R, 450G, and 450B can be efficiently dissipated outside the system, and the temperature rise of the exit side polarizing plates 450R, 450G, and 450B. Can be effectively suppressed.

  In the projector 1000 according to the embodiment, the translucent members 420R, 420G, and 420B shown in FIG. 2 are made of sapphire. Since sapphire is very excellent in thermal conductivity, the heat generated by the incident side polarizing plates 430R, 430G, and 430B can be efficiently dissipated outside the system, and the temperature rise of the incident side polarizing plates 430R, 430G, and 430B. Can be effectively suppressed.

  In the projector 1000 according to the embodiment, as illustrated in FIG. 2B, the projector 1000 includes a heat conductive member 14 that transfers heat between the translucent members 440R, 440G, and 440B and the housing 10. As a result, the heat generated by the exit-side polarizing plates 450R, 450G, and 450B is dissipated to the housing 10 via the translucent members 440R, 440G, and 440B, and the heat conducting member 14, so Performance can be increased.

  Further, the projector 1000 according to the embodiment includes the heat conducting member 16 that transfers heat between the translucent members 420R, 420G, and 420B and the housing 10. As a result, the heat generated by the incident-side polarizing plates 430R, 430G, and 430B is dissipated to the housing 10 through the translucent members 420R, 420G, and 420B and the heat conducting member 16, and thus the heat dissipation of the projector. Performance can be increased.

  As a material of the heat conductive members 14 and 16, for example, a metal such as aluminum or an aluminum alloy can be preferably used.

  In projector 1000 according to the embodiment, a cooling air flow path for cooling translucent members 440R, 440G, and 440B is provided. Thereby, since the exit side polarizing plates 450R, 450G, and 450B can be cooled by the cooling air from the cooling air flow path, the temperature rise of the exit side polarizing plates 450R, 450G, and 450B is suppressed, and the exit side polarizing plates 450R, 450R, Heat generated in 450G and 450B can be efficiently removed.

  In the projector 1000 according to the embodiment, a cooling air flow path for cooling the translucent members 420R, 420G, and 420B is provided. Thereby, since the incident side polarizing plates 430R, 430G, and 430B can be cooled by the cooling air from the cooling air flow path, the temperature increase of the incident side polarizing plates 430R, 430G, and 430B is suppressed, and the incident side polarizing plates 430R, 430R, Heat generated in 430G and 430B can be efficiently removed.

  Although not shown here, the projector 1000 is provided with at least one fan and a plurality of cooling air flow paths for cooling each optical system and the like. Air taken in from the outside of the projector 1000 circulates in the projector 1000 by these fans and a plurality of cooling air flow paths, and is discharged to the outside.

  The projector of the present invention has been described based on the above embodiment, but the present invention is not limited to the above embodiment, and can be implemented in various modes without departing from the scope of the invention. For example, the following modifications are possible.

(1) In the projector 1000 according to the above-described embodiment, sapphire is used as the material of the translucent members 440R, 440G, and 440B, but the present invention is not limited to this. As a material for the light transmissive member, for example, quartz may be used. When quartz is used as the material of the translucent member, the same effect as in the case of sapphire can be obtained.

(2) In the projector 1000 according to the above embodiment, as the light source device, the light source device 110 having the ellipsoidal reflector 114, the arc tube 112 having the emission center near the first focal point of the ellipsoidal reflector 114, and the concave lens 118. However, the present invention is not limited to this, and a light source device having a parabolic reflector and an arc tube having an emission center near the focal point of the parabolic reflector can be preferably used.

(3) In the projector 1000 according to the above-described embodiment, the lens integrator optical system including the first lens array 120 and the second lens array 130 is used as the light uniformizing optical system, but the present invention is limited to this. A rod integrator optical system including a light guide rod can also be preferably used.

(4) The projector 1000 according to the above embodiment is a transmissive projector, but the present invention is not limited to this, and can be applied to a reflective projector. Here, “transmission type” means that the electro-optic modulation device as the light modulation means is a type that transmits light like the transmission type electro-optic modulation device, and “reflection type” means This means that the electro-optic modulation device as the light modulation means is a type that reflects light, such as a reflection-type electro-optic modulation device. Even when the present invention is applied to a reflective projector, the same effect as that of a transmissive projector can be obtained.

(5) The projector 1000 according to the above embodiment uses an electro-optic modulation device having a liquid crystal panel, an incident-side polarizing plate and an emission-side polarizing plate as the electro-optic modulation device, but the present invention is limited to this. It is not a thing. In general, the electro-optic modulation device may be any device that modulates incident light in accordance with image information, and a micromirror light modulation device or the like may be used. For example, a DMD (digital micromirror device) (trademark of TI) can be used as the micromirror light modulator.

(6) The present invention can be applied to a front projection type projector that projects from the side that observes the projected image, and also to a rear projection type projector that projects from the side opposite to the side that observes the projected image. Is also possible.

FIG. 3 is a diagram showing an optical system of the projector 1000 according to the embodiment. FIG. 3 is a diagram for explaining a main part of the projector 1000 according to the first embodiment. FIG. 3 is a diagram for explaining the effect of the projector 1000 according to the first embodiment. The figure shown in order to demonstrate the problem in the conventional projector.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Housing | casing, 12 ... Thermally conductive spacer, 14, 16 ... Thermal conducting member, 100 ... Illuminating device, 100ax ... Illuminating optical axis, 110 ... Light source device, 112 ... Arc tube, 114 ... Ellipsoidal reflector, 116 ... Auxiliary mirror, 118 ... concave lens, 120 ... first lens array, 122 ... first small lens, 130 ... second lens array, 132 ... second small lens, 140 ... polarization conversion element, 150 ... superimposing lens, 200 ... color separation Light guiding optical system, 210, 220 ... Dichroic mirror, 230, 240, 250 ... Reflecting mirror, 260 ... Incident side lens, 270 ... Relay lens, 300R, 300G, 300B ... Condensing lens, 400R, 400G, 400B ... Electro-optical Modulator, 410R, 410G, 410B ... Liquid crystal panel, 420R, 420G, 420B, 440R, 440G, 4 0B, 970R, 970G, 970B ... translucent member, 430R, 430G, 430B ... incident side polarizing plate, 450R, 450G, 450B, 980R, 980G, 980B ... exit side polarizing plate, 460R, 460G, 460B, 960R, 960G , 960B: adhesive layer, 470: light shielding member, 500, 950: cross dichroic prism, 502, 504, 952, 954 ... dielectric multilayer film, 600: projection optical system, 1000: projector, L ₁ , L ₂ , L ₃ , L ₄ ... light, S ₁ , S ₂ , S ₃ ... light incident end face (of the cross dichroic prism), S ₄ ... light exit end face (of the cross dichroic prism), SCR ... screen

Claims (5)

An illuminating device that emits an illuminating luminous flux toward the illuminated area;
Three electro-optic modulators that respectively modulate the illumination light flux from the illumination device according to image information;
A cross dichroic prism having three light incident end faces for incidence of the three color lights modulated by the three electro-optic modulators and a light emission end face for emitting the synthesized color light;
A projection optical system for projecting light from the cross dichroic prism;
A projector comprising three translucent members respectively bonded to the three light incident end faces of the cross dichroic prism via an adhesive layer;
The refractive index of the adhesive layer, the much larger than the refractive index of the cross dichroic prism, less than the refractive index of the translucent member,
Of the synthesized color light, the color light incident on the adhesive layer from the cross dichroic prism passes through the adhesive layer and enters the translucent member, and is emitted from the translucent member to the projection optical system side. Thus , the projector is shielded from light by the light shielding member . The projector according to claim 1 , wherein
The electro-optic modulation device includes a liquid crystal panel that modulates each of a plurality of color lights according to image information, an incident-side polarizing plate disposed on a light incident side of the liquid crystal panel, and a light exit side of the liquid crystal panel An electro-optic modulator having an exit-side polarizing plate,
The projector according to claim 1, wherein the exit-side polarizing plate is bonded to a light incident side surface of the translucent member. The projector according to claim 2 ,
The translucent member is made of sapphire or crystal. The projector according to claim 2 or 3 ,
A housing that houses each optical system inside,
The projector further comprising: a heat conduction member that transfers heat between at least one of the three light-transmissive members and the housing. The projector according to any one of claims 2 to 4 ,
A projector comprising a cooling air flow path for cooling the three translucent members.

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