Patent Publication Number: US-2007103606-A1

Title: Projector

Description:
BACKGROUND  
      1. Technical Field  
      The present invention relates to a projector.  
      2. Related Art  
      In the projector having a liquid crystal device as an electro-optic modulator, a polarizing plate (hereinafter called an incident side polarizing plate in a certain case) as a polarizer is arranged on a light incident side of the liquid crystal device. A polarizing plate (hereinafter called an emitting side polarizing plate in a certain case) as an analyzer is arranged on a light emitting side of the liquid crystal device. In this emitting side polarizing plate, light passing through no emitting side polarizing plate is internally absorbed. Therefore, a large quantity of heat is generated and a rise in temperature of the emitting side polarizing plate is caused. Therefore, the emitting side polarizing plate is deteriorated and polarizing characteristics of the emitting side polarizing plate are reduced, and the contrast of a projecting image is reduced and contrast irregularities, color irregularities, etc. are generated. Accordingly, a problem exists in that quality of the projecting image is reduced.  
      Therefore, a projector having a structure for sticking a transparent substrate of a thermal conductive property to a cross dichroic prism and further sticking the emitting side polarizing plate to this transparent substrate of the thermal conductive property is disclosed as a projector for solving such a problem (e.g., see JP-A-2002-90873 and JP-A-2000-352615). In accordance with this projector, heat generated in the emitting side polarizing plate is radiated to the cross dichroic prism having large heat capacity through the transparent substrate of the thermal conductive property. Therefore, the rise in temperature of the emitting side polarizing plate can be restrained. Therefore, it is possible to restrain that the emitting side polarizing plate is deteriorated and the polarizing characteristics of the emitting side polarizing plate are reduced. As its result, it is possible to restrain that the contrast of the projecting image is reduced and the contrast irregularities, the color irregularities, etc. are generated so that the quality of the projecting image is reduced.  
      However, in a recent projector, high brightness formation of the projector is further advanced, and a large quantity of heat is generated in the emitting side polarizing plate in comparison with the related art, and the rise in temperature of the emitting side polarizing plate is easily caused in comparison with the related art. Therefore, the rise in temperature of the emitting side polarizing plate easily causes the problem that the emitting side polarizing plate is deteriorated and the polarizing characteristics of the emitting side polarizing plate are reduced, and the contrast of the projecting image is reduced and the contrast irregularities, the color irregularities, etc. are generated so that the quality of the projecting image is reduced.  
      Such a problem is not a problem caused in only the emitting side polarizing plate as an analyzer, but is similarly caused in the case of the incident side polarizing plate as a polarizer. Namely, this problem is similarly caused in all the polarizing plates.  
     SUMMARY  
      An advantage of some aspects of the invention can be to provide a projector for restraining that the quality of the projecting image is reduced by the rise in temperature of the polarizing plate in comparison with the related art.  
      An exemplary projector according to an aspect of the invention can comprise: an illuminating device that emits an illuminating light beam; a liquid crystal device that modulates the illuminating light beam from the illuminating device in accordance with image information; a projection optical system that projects light modulated by the liquid crystal device; a polarizing plate arranged on at least one of a light incident side and a light emitting side of the liquid crystal device, and constructed by a polarizing layer; a liquid crystal device side light-transmissive member adhered to a surface of the liquid crystal device side in the polarizing layer of the polarizing plate; and an opposite side light-transmissive member adhered to a surface on the side opposed to the surface of the liquid crystal device, side in the polarizing layer of the polarizing plate; the liquid crystal device side light-transmissive member and the opposite side light-transmissive member are made of an inorganic material.  
      Therefore, in accordance with the projector of the aspect of the invention, there is no generation of disturbance of molecular orientation in the support layer since the polarizing plate has no support layer. Namely, since there is no birefringence due to thermal distortion in the support layer between the polarizing layer and the liquid crystal device, there is no case in which polarizing characteristics as the polarizing plate are greatly reduced and quality of a projecting image is greatly reduced by a rise in temperature of the polarizing plate.  
      Further, in the exemplary projector according to an aspect of the invention, the liquid crystal device side light-transmissive member is adhered to the surface of the liquid crystal device side in the polarizing layer, and the opposite side light-transmissive member is adhered to a surface of the side opposed to the surface of the liquid crystal device side in the polarizing layer. Therefore, heat generated in the polarizing layer can be efficiently transmitted to the liquid crystal device side light-transmissive member and the opposite side light-transmissive member without interposing the support layer. Therefore, the rise in temperature of the polarizing layer can be restrained.  
      Further, in the exemplary projector according to an aspect of the invention, a predetermined mechanical strength can be obtained since the polarizing plate constructed by the polarizing layer is nipped from both sides by the liquid crystal device side light-transmissive member and the opposite side light-transmissive member.  
      Since the support layer used in the polarizing plate is normally an organic member, its coefficient of thermal conductivity is low and temperature is easily raised. Further, the support layer made of the organic member is deteriorated and is disturbed in molecular orientation under a condition of high temperature and high humidity. Accordingly, the polarizing plate having the support layer made of the organic member is greatly reduced in polarizing characteristics by heat and greatly reduces quality of the projecting image.  
      However, in the exemplary projector according to an aspect of the invention, such a disadvantage is not caused since the polarizing plate has no support layer. Namely, the reduction in quality of the projecting image can be restrained.  
      In the projector of the aspect of the invention, the liquid crystal device side light-transmissive member, the polarizing layer and the opposite side light-transmissive member are respectively preferably stuck by a pressure sensitive adhesive or an adhesive.  
      Generation of surface reflection at interfaces between the respective members is restrained and light transmittance can be raised by setting such a construction. As its result, brightness of the projecting image can be improved.  
      Further, even when linear expansion coefficients of the liquid crystal device side light-transmissive member, the polarizing layer and the opposite side light-transmissive member are different from each other, no separation on sticking faces between the respective members is easily caused, and a reduction in long period reliability can be restrained.  
      In the exemplary projector according to an aspect of the invention, the liquid crystal device side light-transmissive member and the opposite side light-transmissive member can be are a light-transmissive substrate made of sapphire or crystal.  
      Since the light-transmissive substrate made of these materials is very excellent in thermal conductive property, heat generated in the polarizing layer can be efficiently radiated to the system exterior, and the rise in temperature of the polarizing layer can be effectively restrained.  
      In the exemplary projector according to an aspect of the invention, the light-transmissive substrate made of sapphire or crystal can be arranged with respect to the polarizing layer such that an optic axis of the light-transmissive substrate made of sapphire or crystal is approximately parallel to or approximately perpendicular to a polarizing axis of the polarizing layer.  
      When the light-transmissive substrate made of sapphire or crystal is used as the liquid crystal device side light-transmissive member and the opposite side light-transmissive member, no polarizing state of light passing through the light-transmissive substrate made of sapphire or crystal is also changed by setting the above construction.  
      Further, thermal deformation of the polarizing layer can be restrained by conforming an axial direction large in thermal expansion in the light-transmissive substrate made of sapphire or crystal, and a stretched direction of the polarizing layer.  
      In this specification, “the polarizing axis of the polarizing layer” means the polarizing axis of light passing the polarizing layer.  
      Further, in the exemplary projector according to an aspect of the invention, an amount of deviation from the optic axis of the liquid crystal device side light-transmissive member to the axis that may be in parallel with or perpendicular to the polarizing axis of the polarizing layer may be smaller than an amount of deviation from the optic axis of the opposite side light-transmissive member to the axis that is in parallel with or perpendicular to the polarizing axis of the polarizing layer.  
      The above structure can constrain the chance of a polarizing state of light, even if the light-transmissive substrates as the light-transmissive members are made of sapphire or quartz. Such light emits from the polarizing layer and enters into the liquid crystal device, if the polarizing layer is located at the light incident side. Otherwise, the light bundle is incident into the polarizing layer and detected, if the polarizing layer is located at the light emitting side.  
      In the exemplary projector according to an aspect of the invention, the liquid crystal device side light-transmissive member and the opposite side light-transmissive member can be a light-transmissive substrate made of quartz glass, hard glass, crystallized glass or a sintered body of cubic crystal.  
      Since the light-transmissive substrate made of these materials is small in birefringence, a reduction in quality of a light beam passing the light-transmissive substrate can be restrained, and a reduction in quality of the light beam incident to the polarizing plate or the light beam emitted from the polarizing plate can be restrained. Further, since the light-transmissive substrate made of these materials is small in thermal expansion coefficient, deformation of the polarizing plate itself can be restrained by adhering the polarizing plate having a property large in extension and deformation due to heat to the light-transmissive substrate made of such a material small in thermal expansion coefficient.  
      In the exemplary projector according to an aspect of the invention, one light-transmissive member of the liquid crystal device side light-transmissive member and the opposite side light-transmissive member can be a light-transmissive substrate made of quartz glass, hard glass, crystallized glass or a sintered body of cubic crystal, and the other light-transmissive member is a light-transmissive substrate made of sapphire or crystal.  
      When the temperature of a vicinity of the polarizing layer is higher than a predetermined temperature, the liquid crystal device side light-transmissive member is preferably the light-transmissive substrate made of sapphire or crystal from the viewpoint of reducing thermal load of the polarizing layer, The opposite side light-transmissive member is preferably the light-transmissive substrate made of quartz glass, hard glass, crystallized glass or the sintered body of the cubic crystal from the viewpoint of restraining the change of a polarizing state of the light beam incident to the polarizing layer or the light beam emitted from the polarizing layer.  
      When the temperature of the vicinity of the polarizing layer is lower than the predetermined temperature, the liquid crystal device side light-transmissive member is preferably the light-transmissive substrate made of quartz glass, hard glass, crystallized glass or the sintered body of the cubic crystal from the viewpoint of restraining the change of the polarizing state of the light beam incident to the polarizing layer or the light beam emitted from the polarizing layer. The opposite side light-transmissive member is preferably the light-transmissive substrate made of sapphire or crystal from the viewpoint of reducing thermal load of the polarizing layer.  
      As the liquid crystal device side light-transmissive member and the opposite side light-transmissive member, it is also possible to preferably use a light-transmissive substrate constructed by white plate glass, a light-transmissive substrate constructed by Pyrex®, a light-transmissive substrate constructed by YAG polycrystal, a light-transmissive substrate constructed by oxynitriding aluminum, etc. in addition to the above materials,  
      In the exemplary projector according to an aspect of the invention, a light-transmissive member arranged on the light incident side among the liquid crystal device side light-transmissive member and the opposite side light-transmissive member can be a polarization separating optical element having a function for transmitting linearly polarized light having an axis in a predetermined direction among incident light, and reflecting the other light.  
      In accordance with such a construction, linearly polarized light having an axis in a predetermined direction among light incident to the light-transmissive member is transmitted through the polarization separating optical element, and is incident to the polarizing layer. On the other hand, the other light, i.e., light (a polarizing component not transmitted through the polarizing layer) to be inhibited in advancement to the polarizing layer is reflected on the polarization separating optical element, and is escaped to the system exterior. Therefore, light of the polarizing component not transmitted through the polarizing layer is almost removed by the polarization separating optical element as a former stage. Therefore, heat generation itself in the polarizing layer is effectively restrained, and the rise in temperature of the polarizing layer can be further effectively restrained.  
      In the projector of the aspect of the invention, as the polarization separating optical element, it is possible to preferably use a polarization separating optical element constructed by a dielectric multilayer film, a polarization separating optical element of a wire grid type formed by arraying many fine metallic thin wires, a polarization separating optical element using an XY type polarizing film having polarizing characteristics of an XY type by laminating plural films having a biaxial direction property, etc.  
      In the exemplary projector according to an aspect of the invention, the projector can further comprise a condenser lens arranged on the light incident side of the liquid crystal device, and the opposite side light-transmissive member adhered to the surface of the polarizing layer arranged on the light incident side of the liquid crystal device is adhered to a light emitting face of the condenser lens.  
      In accordance with such a construction, heat generated in the polarizing layer (light incident side polarizing plate) arranged on the light incident side of the liquid crystal device can be transmitted to the condenser lens through the opposite side light-transmissive member. Therefore, the rise in temperature of the polarizing layer can be further restrained.  
      Further, since the opposite side light-transmissive member is adhered to the condenser lens comparatively large in heat capacity, the rise in temperature of the opposite side light-transmissive member and the incident side polarizing plate is restrained and heat radiating performance of the projector can be raised.  
      In the exemplary projector according to an aspect of the invention, the projector can further comprise: a color separating light guide optical system that separates the illuminating light beam from the illuminating device into plural color lights, and guides the color lights to an illuminated area; plural liquid crystal devices that modulates each of the plural color lights separated by the color separating light guide optical system in accordance with the image information as the liquid crystal device; and a cross dichroic prism having plural light incident end faces to which the respective color lights modulated by the plural liquid crystal devices are incident, and also having a light emitting end face that emits synthesized color light, and the polarizing plate adhered to the liquid crystal device side light-transmissive member and the opposite side light-transmissive member is arranged on the light emitting side of at least one liquid crystal device among the plural liquid crystal devices, and the opposite side light-transmissive member is adhered to the light incident end face of the cross dichroic prism.  
      In accordance with such a construction, heat generated in the polarizing layer in the polarizing plate (emitting side polarizing plate) arranged on the light emitting side of at least one liquid crystal device among the plural liquid crystal devices can be transmitted to the cross dichroic prism through the opposite side light-transmissive member. Therefore, the rise in temperature of the polarizing layer can be further restrained.  
      Further, since the opposite side light-transmissive member is adhered to the cross dichroic prism comparatively large in heat capacity, the rise in temperature of the opposite side light-transmissive member and the emitting side polarizing plate is restrained, and heat radiating performance of the projector can be raised.  
      In the exemplary projector according to an aspect of the invention, the projector can further comprise: a case that internally stores each optical system; and a thermal conductive member that transmits heat in at least one of a portion between the liquid crystal device side light-transmissive member and the case, and a portion between the opposite side light-transmissive member and the case.  
      In accordance with such a construction, heat generated in the polarizing layer is radiated to the case through the liquid crystal device side light-transmissive member, the opposite side light-transmissive member and the thermal conductive member. Therefore, heat radiating performance of the projector can be raised.  
      The thermal conductive member is preferably made of a metal.  
      In the exemplary projector according to an aspect of the invention, a cool wind flow path that cools at least one of the liquid crystal device side light-transmissive member and the opposite side light-transmissive member can be arranged.  
      In accordance with such a construction, at least one of the liquid crystal device side light-transmissive member and the opposite side light-transmissive member can be cooled by a cool wind from the cool wind flow path. Therefore, the rise in temperature of at least one of the liquid crystal device side light-transmissive member and the opposite side light-transmissive member is restrained, and heat generated in the polarizing layer can be efficiently removed. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The invention will be described with reference to the accompanying drawings, wherein like numbers reference like elements.  
       FIG. 1  is a view showing an optical system of a projector  1000  in accordance with exemplary embodiment 1.  
       FIGS. 2A and 2B  are views shown to explain an optical device  510  in accordance with exemplary embodiment 1.  
       FIGS. 3A and 3B  are views shown to explain a main portion of the optical device  510  in accordance with exemplary embodiment 1.  
       FIGS. 4A and 4B  are views shown to explain an optical device  512  in accordance with a modified example of exemplary embodiment 1.  
       FIGS. 5A and 5B  are views shown to explain an optical device  514  in accordance with exemplary embodiment 2.  
       FIG. 6  is a view in which a vicinity of a polarization separating optical element  460 R is seen from a side face.  
       FIGS. 7A and 7B  are views shown to explain a projector  1006  in accordance with exemplary embodiment 3.  
       FIGS. 8A and 8B  are views shown to explain a projector  1008  in accordance with exemplary embodiment 4.  
       FIGS. 9A and 9B  are views shown to explain a projector  1010  in accordance with exemplary embodiment 5. 
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS  
      Optical devices and projectors of the invention will next be explained on the basis of exemplary embodiments shown in the drawings.  
     Exemplary Embodiment 1  
       FIG. 1  is a view showing an optical system of a projector  1000  in accordance with exemplary embodiment 1.  FIGS. 2A and 2B  are views shown to explain an optical device  510  in accordance with exemplary embodiment 1.  FIG. 2A  is a view in which the optical device  510  is seen from an upper face.  FIG. 2B  is an A-A sectional view of  FIG. 2A .  FIGS. 3A and 3B  are views shown to explain a main portion of the optical device  510  in accordance with exemplary embodiment 1.  FIG. 3A  is a view in which a vicinity of an emitting side polarizing plate  440 R is seen from a side face.  FIG. 3B  is a view in which a vicinity of an incident side polarizing plate  420 R is seen from a side face.  
      As shown in  FIG. 1 , the projector  1000  in accordance with exemplary embodiment 1 has an illuminating device  100 , a color separating light guide optical system  200 , the optical device  510  and a projection optical system  600 . The color separating light guide optical system  200  separates an illuminating light beam from the illuminating device  100  into three color lights of red light, green light and blue light, and guides these color lights to an illuminated area. The optical device  510  has three liquid crystal devices  410 R,  410 G,  410 B as an electro-optic modulator for modulating each of the three color lights separated by the color separating light guide optical system  200  in accordance with image information, and also has a cross dichroic prism  500  for synthesizing the color lights modulated by the three liquid crystal devices  410 R,  410 G,  410 B. The projection optical system  600  projects the light synthesized by the cross dichroic prism  500  onto a projecting face such as a screen SCR, etc. Each of these optical systems is stored in a case  10 .  
      The illuminating device  100  has a light source device  110  as a light source for emitting the illuminating light beam approximately parallel on the illuminated area side, and also has a first lens array  120  having plural first small lenses  122  for dividing the illuminating light beam emitted from the light source device  110  into plural partial light beams. The illuminating device  100  also has a second lens array  130  having plural second small lenses  132  corresponding to the plural first small lenses  122  of the first lens array  120 , and has a polarization converting element  140  for conforming the illuminating light beam not conformed in a polarizing direction and emitted from the light source device  110  to linearly polarized light of about one kind. The illuminating device  100  further has a superposing lens  150  for superposing each partial light beam emitted from the polarization converting element  140  in the illuminated area.  
      The light source device  110  has an elliptical face reflector  114  as a reflector, and also has a light emitting tube  112  having a light emitting center near a first focal point of the elliptical face reflector  114 . The light source device  110  also has an auxiliary mirror  116  having a reflecting face opposed to a reflecting concave face of the elliptical face reflector  114 , and also has a concave lens  118  for converting convergent light reflected on the elliptical face reflector  114  into approximately parallel light. The light source device  110  emits a light beam with an illuminating optical axis  100   ax  as a central axis.  
      The light emitting tube  112  has a tube bulb portion, and a pair of seal portions extending on both sides of the tube bulb portion.  
      The elliptical face reflector  114  has a neck shape portion of a sleeve shape inserted and fixedly attached to one seal portion of the light emitting tube  112 , and also has a reflecting concave face for reflecting light radiated from the light emitting tube  112  toward a second focal point position.  
      The auxiliary mirror  116  is arranged so as to be opposed to the elliptical face reflector  114  through the tube bulb portion of the light emitting tube  112 , and returns light not directed to the elliptical face reflector  114  among the light radiated from the light emitting tube  112  to the light emitting tube  112 , and makes this returned light incident to the elliptical face reflector  114 .  
      The concave lens  118  is arranged on the illuminated area side of the elliptical face reflector  114 . The concave lens  118  is constructed so as to set light from the elliptical face reflector  114  to be approximately parallel.  
      The first lens array  120  has a function as a light beam dividing optical element for dividing light from the concave lens  118  into plural partial light beams. The first lens array  120  has a construction having the plural first small lenses  122  arrayed in a matrix shape within a plane perpendicular to the illuminating optical axis  100   ax . An outer shape of the first small lens  122  is a similar shape with respect to the outer shape of an image forming area of the liquid crystal devices  410 R,  410 G,  410 B although an explanation using illustration is omitted.  
      The second lens array  130  is an optical element for converging the plural partial light beams divided by the first lens array  120 . Similar to the first lens array  120 , the second lens array  130  has a construction having the plural second small lenses  132  arrayed in a matrix shape within a plane perpendicular to the illuminating optical axis  100   ax.    
      The polarization converting element  140  emits each partial light beam divided by the first lens array  120  as linearly polarized light of about one kind conformed in a polarizing direction.  
      The polarization converting element  140  has a polarization separating layer for transmitting one linearly polarized light component among polarizing components included in the illuminating light beam from the light source device  110 , and reflecting the other linearly polarized light component in a direction perpendicular to the illuminating optical axis  100   ax . The polarization converting element  140  also has a reflecting layer for reflecting the other linearly polarized light component reflected on the polarization separating layer in a direction parallel to the illuminating optical axis  100   ax . The polarization converting element  140  further has a phase difference plate for converting the other linearly polarized light component reflected on the reflecting layer into one linearly polarized light component.  
      The superposing lens  150  is an optical element for converging the plural partial light beams transmitted via the first lens array  120 , the second lens array  130  and the polarization converting element  140 , and superposing the plural partial light beams near the image forming area in the liquid crystal devices  410 R,  410 G,  410 B. The superposing lens  150  shown in  FIG. 1  is constructed by one lens, but may be also constructed by a composite lens formed by combining plural lenses.  
      The color separating light guide optical system  200  has dichroic mirrors  210 ,  220 , reflecting mirrors  230 ,  240 ,  250 , an incident side lens  260  and a relay lens  270 . The color separating light guide optical system  200  has a function for separating the illuminating light beam emitted from the illuminating device  100  into the three color lights of red light, green light and blue light, and guiding the respective color lights to the liquid crystal devices  410 R,  410 G,  410 B as an illuminating object.  
      The dichroic mirrors  210 ,  220  are optical elements each forming a wavelength selecting film for reflecting the light beam of a predetermined wavelength area onto a substrate, and transmitting the light beams of other wavelength areas. The dichroic mirror  210  arranged at the former stage of an optical path is a mirror for reflecting a red light component, and transmitting the other color light components. The dichroic mirror  220  arranged at the latter stage of the optical path is a mirror for transmitting a blue light component and reflecting a green light component.  
      The red light component reflected on the dichroic mirror  210  is bent by the reflecting mirror  230 , and is incident to the liquid crystal device  410 R for red light through a condenser lens  300 R. On the other hand, the green light component among the green light component and the blue light component transmitted through the dichroic mirror  210  is reflected on the dichroic mirror  220  and is incident to the liquid crystal device  410 G for green light through a condenser lens  300 G Further, the blue light component transmitted through the dichroic mirror  220  is converged and bent by the incident side lens  260 , the relay lens  270  and the reflecting mirrors  240 ,  250 , and is incident to the liquid crystal device  410 B for blue light through a condenser lens  300 B. The incident side lens  260 , the relay lens  270  and the reflecting mirrors  240 ,  250  have a function for guiding the blue light component transmitted through the dichroic mirror  220  until the liquid crystal device  410 B for blue light.  
      Such incident side lens  260 , relay lens  270  and reflecting mirrors  240 ,  250  are arranged in the optical path of the blue light to prevent a reduction of utilization efficiency of light due to dispersion of light, etc. since the length of the optical path of the blue light is longer than the lengths of the optical paths of the other color lights. In the projector  1000  in accordance with exemplary embodiment 1, such a construction is set since the length of the optical path of the blue light is long. However, a construction for lengthening the length of the optical path of the red light and using the incident side lens  260 , the relay lens  270  and the reflecting mirrors  240 ,  250  in the optical path of the red light is also considered.  
      The optical device  510  has the three liquid crystal devices  410 R,  410 G,  410 B for modulating the respective three color lights separated by the color separating light guide optical system  200  in accordance with image information. The optical device  510  also has the cross dichroic prism  500  for synthesizing the respective color lights modulated by the three liquid crystal devices  410 R,  410 G,  410 B. The optical device  510  also has the three condenser lenses  300 R,  300 G,  300 B arranged on the respective light incident sides of the three liquid crystal devices  410 R,  410 G,  410 B. The optical device  510  also has three incident side polarizing plates  420 R,  420 G,  420 B arranged on the respective light incident sides of the three liquid crystal devices  410 R,  410 G,  410 B. The optical device  510  also has three second light-transmissive members  430 R,  430 G,  430 B adhered to faces of the light transmitting sides of the three incident side polarizing plates  420 R,  420 G,  420 B. The optical device  510  also has three emitting side polarizing plates  440 R,  440 G,  440 B arranged on the respective light transmitting sides of the three liquid crystal devices  410 R,  410 G,  410 B. The optical device  510  further has three first light-transmissive members  450 R,  450 G,  450 B respectively adhered to faces of the light incident sides in the three emitting side polarizing plates  440 R,  440 G,  440 B.  
      The condenser lens  300 R is arranged to convert each partial light beam emitted from the second lens array  130  into light approximately parallel with respect to a principal ray of each partial light beam. The condenser lens  300 R is held by an unillustrated holding member of a thermal conductive property, and is arranged in the case  10  through this holding member of the thermal conductive property. The other condenser lenses  300 G,  300 B are also constructed similarly to the condenser lens  300 R.  
      The liquid crystal devices  410 R,  410 G,  410 B modulate the illuminating light beam in accordance with image information, and become an illuminating object of the illuminating device  100 .  
      In each of the liquid crystal devices  410 R,  410 G,  410 B, a liquid crystal as an electro-optic substance is enclosed in a pair of transparent glass substrates. For example, a polysilicon TFT is set to a switching element, and a polarizing direction of linearly polarized light of one kind emitted from the incident side polarizing plates  420 R,  420 G,  420 B is modulated in accordance with a given image signal. The liquid crystal devices  410 R,  410 G,  410 B are held in a liquid crystal device holding frame constructed by e.g., a die-cast frame manufactured by aluminum although this construction is omitted in illustration of the drawings.  
      As shown in  FIGS. 2A and 28 , the incident side polarizing plates  420 R,  420 G,  420 B are arranged between the condenser lenses  300 R,  300 G,  300 B and the liquid crystal devices  410 R,  410 G,  410 B, and have a function for transmitting only the linearly polarized light having an axis in a predetermined direction among lights emitted from the condenser lenses  300 R,  300 G,  300 B, and absorbing the other lights.  
      As shown in  FIG. 3B , the incident side polarizing plate  420 R has a polarizing layer  20  and a support layer  22  for supporting the polarizing layer  20 . The incident side polarizing plate  420 R is adhered to a light emitting face of the condenser lens  300 R through an adhesive layer C such that the support layer  22  is located on the side (condenser lens  300 R side) opposed to the liquid crystal device  410 R in the polarizing layer  20 . As the polarizing layer  20 , for example, it is possible to preferably use a polarizing layer formed such that polyvinyl alcohol (PVA) is dyed by iodine or a dichromatic dye and is uniaxially stretched and molecules of this dye are arrayed in one direction. The polarizing layer  20  formed in this way absorbs the polarized light of a direction parallel to the above uniaxially stretched direction, and transmits the polarized light of a direction perpendicular to the above uniaxially stretched direction. In the polarizing layer  20 , force intended to be returned from a stretched state to an original state is large. Accordingly, a support layer for supporting the polarizing layer  20  is arranged to regulate this force. As the support layer  22 , it is possible to preferably use a support layer constructed by triacetyl cellulose (TAC). The other incident side polarizing plates  420 G,  420 B are also constructed similarly to the incident side polarizing plate  420 R.  
      The second light-transmissive members  430 R,  430 G,  430 B are respectively arranged on the liquid crystal device sides (the light emitting sides) of the incident side polarizing plates  420 R,  420 G,  420 B. For example, the second light-transmissive members  430 R,  430 G,  430 B are a light-transmissive substrate made of sapphire. The light-transmissive substrate made of sapphire has a high thermal conductivity coefficient of about 40 W/(m·K) and is very high in hardness and has a small coefficient of thermal expansion and is not easily damaged and has a high transparent degree. When a cheap property is seriously considered as brightness of a middle degree, a light-transmissive substrate made of crystal having a thermal conductivity coefficient of about 10 W/(m·K) may be also used. The thicknesses of the second light-transmissive members  430 R,  430 G,  430 B are preferably set to 0.2 mm or more from the viewpoint of the thermal conductive property, and are preferably set to 2.0 mm or less from the viewpoint of compactness of the device.  
      As shown in  FIG. 3B , a face of the light incident side in the incident side polarizing plate  420 R and a face of the light emitting side in the condenser lens  300 R are adhered through an adhesive layer C. Further, a face of the light emitting side in the incident side polarizing plate  420 R and a face of the light incident side in the second light-transmissive member  430 R are stuck through a sticking layer D. Thus, generation of surface reflection at the interface between the respective members is restrained, and light transmittance can be raised. As its result, brightness of a projecting image can be improved. Further, even when the linear expansion coefficients of the second light-transmissive member  430 R, the incident side polarizing plate  420 R and the condenser lens  300 R are different from each other, no separation on sticking faces between the respective members is easily caused, and a reduction of long period reliability can be restrained. A face of the light incident side in the incident side polarizing plate  420 R and a face of the light emitting side in the condenser lens  300 R may be also stuck by a pressure sensitive adhesive. A face of the light emitting side in the incident side polarizing plate  420 R and a face of the light incident side in the second light-transmissive member  430 R may be also adhered by an adhesive. Peripheral portions of the other incident side polarizing plates  420 G,  420 B are also constructed similarly to the peripheral portion of the incident side polarizing plate  420 R.  
      The adhesive layer C is formed around the incident side polarizing plates  420 R,  420 G;  420 B. For example, an adhesive of an UV hardening property, an adhesive of a visible light short wavelength hardening property, etc. can be suitably used as the adhesive used in the adhesive layer C.  
      As shown in  FIGS. 2A and 2B , the emitting side polarizing plates  440 R,  440 G,  440 B are arranged between the liquid crystal devices  410 R,  410 G,  410 B and the cross dichroic prism  500 , and have a function for transmitting only linearly polarized light having an axis in a predetermined direction among lights emitted from the liquid crystal devices  410 R,  410 G,  410 B, and absorbing the other lights.  
      As shown in  FIG. 3A , the emitting side polarizing plate  440 R has a polarizing layer  40  and a support layer  42  for supporting the polarizing layer  40 . The emitting side polarizing plate  440 R is adhered to a light incident end face of the cross dichroic prism  500  through the adhesive layer C such that the support layer  42  is located on the side (cross dichroic prism  500  side) opposed to the liquid crystal device  410 R in the polarizing layer  40 . A material similar to that of the incident side polarizing plate  420 R can be used as the polarizing layer  40  and the support layer  42 . The other emitting side polarizing plates  440 G,  440 B are also constructed similarly to the emitting side polarizing plate  440 R.  
      First light-transmissive members  450 R,  450 G,  450 B are respectively arranged on the liquid crystal device sides (light incident sides) of the emitting side polarizing plates  440 R,  440 G,  440 B. Unillustrated reflection preventing layers are formed on faces of the liquid crystal device sides of the first light-transmissive members  450 R,  450 G,  450 B. Similar to the second light-transmissive members  430 R,  430 G,  430 B, the first light-transmissive members  450 R,  450 G  450 B are formed by a light-transmissive substrate made of e.g., sapphire.  
      As shown in  FIG. 3A , a face of the light incident side in the emitting side polarizing plate  440 R and a face of the light emitting side in the first light-transmissive member  450 R, and a face of the light emitting side in the emitting side polarizing plate  440 R and a light incident end face in the cross dichroic prism  500  are respectively adhered through the adhesive layer C. Thus, generation of surface reflection at interfaces between the respective members is restrained, and light transmittance can be raised. As its result, brightness of a projecting image can be improved. Further, even when linear expansion coefficients of the first light-transmissive member  450 R, the emitting side polarizing plate  440 R and the cross dichroic prism  500  are different from each other, no separation on sticking faces between the respective members is easily caused, and a reduction of long period reliability can be restrained. A pressure sensitive adhesive may be also used instead of the adhesive. Peripheral portions of the other emitting side polarizing plates  440 G,  440 B are constructed similarly to the peripheral portion of the emitting side polarizing plate  440 R.  
      The adhesive layer C is formed around the emitting side polarizing plates  440 R,  440 G,  440 B.  
      These incident side polarizing plates  420 R,  420 G,  420 B and emitting side polarizing plates  440 R,  440 G,  440 B are set and arranged such that the directions of mutual polarizing axes are perpendicular.  
      The cross dichroic prism  500  is an optical element for synthesizing an optical image modulated every each color light emitted from each of the emitting side polarizing plates  440 R,  440 G,  440 B, and forming a color image. As shown in  FIG. 2A , the cross dichroic prism  500  has three light incident end faces to which color lights modulated by the liquid crystal devices  410 R,  410 G,  410 B are respectively incident, and also has a light emitting end face for emitting the synthesized color light. This cross dichroic prism  500  approximately has a square shape seen from a plane and formed by sticking four rectangular prisms. A dielectric multi-layer film is formed at an interface of an approximately X-shape at which the rectangular prisms are stuck to each other. The dielectric multi-layer film formed at one interface of the approximately X-shape reflects red light, and the dielectric multi-layer film formed at the other interface reflects blue light. The red light and the blue light are bent by these dielectric multi-layer films, and their advancing directions are conformed to the advancing direction of green light so that the three color lights are synthesized.  
      The cross dichroic prism  500  is arranged in the case  10  through a spacer  12  of a thermal conductive property (see  FIG. 2B ).  
      A color image emitted from the cross dichroic prism  500  is enlarged and projected by the projection optical system  600 , and a large screen image is formed on the screen SCR.  
      At least one fan and plural cool wind flow paths for cooling each optical system, etc. are arranged within the projector  1000  although their illustration is omitted. The air taken-in from the exterior of the projector  1000  is circulated within the projector  1000  by these fan and plural cool wind flow paths, and is discharged to the exterior. As shown in  FIGS. 2A and 2B , the air flowed-in from a ventilating hole (cool wind flow path) arranged in the case  10  promotes heat radiation from the optical device  510 .  
      Thus, heat of each optical system (each member of the optical device  510 ) of the projector  1000  can be efficiently removed.  
      The projector  1000  in accordance with exemplary embodiment 1 constructed in this way will be further explained in detail on the basis of the construction of a member arranged in the optical path of red light among the optical paths of the respective three color lights to simplify the following explanation.  
      In the projector  1000  in accordance with exemplary embodiment 1, as shown in  FIGS. 2A and 2B , the first light-transmissive member  450 R and the emitting side polarizing plate  440 R are arranged between the liquid crystal device  410 R and the cross dichroic prism  500 . The first light-transmissive member  450 R is adhered to a face of the light incident side in the emitting side polarizing plate  440 R. A face of the light emitting side in the emitting side polarizing plate  440 R is adhered to a light incident end face in the cross dichroic prism  500 .  
      Therefore, heat generated in the emitting side polarizing plate  440 R can be transmitted from both sides of the emitting side polarizing plate  440 R to the first light-transmissive member  450 R and the cross dichroic prism  500 . Therefore, a rise in temperature of the emitting side polarizing plate  440 R can be restrained. Further, since no emitting side polarizing plate  440 R comes in contact with the outside air, the invasion of moisture from the outside air can be restrained. Therefore, it is possible to restrain that the support layer of the emitting side polarizing plate  440 R is expanded and deformed by the rise in temperature of the emitting side polarizing plate  440 R and the invasion of moisture from the outside air. Thus, generation of disturbance of molecular orientation in the support layer can be restrained. As its result, it is possible to restrain that polarization characteristics as the emitting side polarizing plate are reduced and quality of the light beam passing the emitting side polarizing plate  440 R is reduced.  
      Accordingly, the projector  1000  in accordance with exemplary embodiment 1 becomes a projector for restraining that the quality of a projecting image is reduced by the rise in temperature of the emitting side polarizing plate in comparison with the related art.  
      Further, in the projector  1000  in accordance with exemplary embodiment 1, the emitting side polarizing plate  440 R is adhered to the cross dichroic prism  500  comparatively large in heat capacity. Therefore, the rise in temperature of the emitting side polarizing plate  440 R is restrained, and heat radiating performance of the projector can be raised. Further, since the cross dichroic prism  500  is connected to the case  10  through the spacer  12  of the thermal conductive property, heat capacity can be further increased and the heat radiating performance of the projector can be further raised.  
      In the projector  1000  in accordance with exemplary embodiment 1, as shown in  FIG. 3A , the emitting side polarizing plate  440 R has the support layer  42  for supporting the polarizing layer  40  on only the light emitting side of the polarizing layer  40 .  
      Thus, there is no generation of disturbance of the molecular orientation in the support layer of the light incident side. Namely, since no birefringence due to thermal distortion in the support layer exists between the polarizing layer  40  and the liquid crystal device  410 R, light modulated by the liquid crystal device  410 R reaches the polarizing layer  40  in a state as it is. Therefore, there is no case in which polarizing characteristics as the emitting side polarizing plate are greatly reduced and the quality of the projecting image is greatly reduced by the rise in temperature of the emitting side polarizing plate  440 R. In this case, even if the polarizing characteristics in the support layer  42  of the light emitting side are slightly reduced by the rise in temperature, its reduction of the polarizing characteristics is not detected as light in the polarizing layer  40 . Therefore, no quality of the projecting image is greatly reduced.  
      In the projector  1000  in accordance with exemplary embodiment 1, as mentioned above, the first light-transmissive member  450 R is adhered to the face of the light incident side in the emitting side polarizing plate  440 R, and the face of the light emitting side in the emitting side polarizing plate  440 R is adhered to the light incident end face in the cross dichroic prism  500 . Therefore, even when the emitting side polarizing plate  440 R has a structure having the support layer  42  on only the light emitting side of the polarizing layer  40 , the projector  1000  can obtain a predetermined mechanical strength.  
      In the projector  1000  in accordance with exemplary embodiment 1, as shown in  FIGS. 2A and 2B , the incident side polarizing plate  420 R and the second light-transmissive member  430 R are arranged between the condenser lens  300 R and the liquid crystal device  410 R. The second light-transmissive member  430 R is adhered to the face of the light emitting side in the incident side polarizing plate  420 R. The face of the light incident side in the incident side polarizing plate  420 R is adhered to the face of the light emitting side in the condenser lens  300 R.  
      Thus, heat generated in the incident side polarizing plate  420 R can reach the second light-transmissive member  430 R and the condenser lens  300 R from both sides of the incident side polarizing plate  420 R. Therefore, the rise in temperature of the incident side polarizing plate  420 R can be restrained. Further, since no incident side polarizing plate  420 R comes in contact with the outside air, the invasion of moisture from the outside air can be restrained. Therefore, it is possible to restrain that the support layer of the incident side polarizing plate  420 R is expanded and deformed by the rise in temperature of the incident side polarizing plate  420 R and the invasion of moisture from the outside air. Thus, the generation of disturbance of molecular orientation in the support layer can be restrained. As its result, it is possible to restrain that polarizing characteristics as the incident side polarizing plate are reduced and quality of a light beam passing the incident side polarizing plate  420 R is reduced.  
      Therefore, the projector  1000  in accordance with exemplary embodiment 1 becomes a projector for further restraining that the quality of the projecting image is reduced by the rise in temperature of the incident side polarizing plate and the emitting side polarizing plate in comparison with the related art.  
      Further, in the projector  1000  in accordance with exemplary embodiment 1, the incident side polarizing plate  420 R is adhered to the condenser lens  300 R comparatively large in heat capacity. Therefore, the rise in temperature of the incident side polarizing plate  420 R is restrained and heat radiating performance of the projector can be raised. Further, since the condenser lens  300 R is connected to the case  10  through a holding member of a thermal conductive property, heat capacity can be further increased and the heat radiating performance of the projector can be further raised.  
      In the projector  1000  in accordance with exemplary embodiment 1, as shown in  FIG. 3B , the incident side polarizing plate  420 R has the support layer  22  for supporting the polarizing layer  20  on only the light incident side of the polarizing layer  20 .  
      Thus, there is no generation of disturbance of molecular orientation in the support layer of the light emitting side. Namely, since there is no birefringence due to thermal distortion in the support layer between the polarizing layer  20  and the liquid crystal device  410 R, light properly conformed to linearly polarized light having an axis in a predetermined direction in the polarizing layer  20  reaches the liquid crystal device  410 R in a state as it is. Therefore, there is no case in which polarizing characteristics as the incident side polarizing plate are greatly reduced and quality of the projecting image is greatly reduced by the rise in temperature of the incident side polarizing plate. In this case, even if the polarizing characteristics in the support layer  22  of the light incident side are slightly reduced by the rise in temperature, this reduction of the polarizing characteristics is compensated by the polarizing layer  20  of the incident side polarizing plate  420 R, and is not detected as light in error by the polarizing layer  40  of the emitting side polarizing plate  440 R. Therefore, no quality of the projecting image is greatly reduced.  
      In the projector  1000  in accordance with exemplary embodiment 1, as mentioned above, the second light-transmissive member  430 R is adhered to the face of the light emitting side in the incident side polarizing plate  420 R. Further, the face of the light incident side in the incident side polarizing plate  420 R is adhered to the face of the light emitting side in the condenser lens  300 R. Therefore, even when the incident side polarizing plate  420 R has a structure having the support layer  22  on only the light incident side of the polarizing layer  20 , the projector  1000  has a predetermined mechanical strength.  
      In the projector  1000  in accordance with exemplary embodiment 1, the first light-transmissive member  450 R is a light-transmissive substrate made of sapphire.  
      Since the light-transmissive substrate made of sapphire is very excellent in thermal conductive property, heat generated in the emitting side polarizing plate  440 R can be efficiently radiated to the system exterior, and deterioration of the polarizing characteristics caused by the rise in temperature of the emitting side polarizing plate  440 R can be further restrained.  
      In the projector  1000  in accordance with exemplary embodiment 1, the first light-transmissive member  450 R is arranged with respect to the emitting side polarizing plate  440 R such that an optic axis of the first light-transmissive member  450 R is approximately parallel to or approximately perpendicular to a polarizing axis of the polarizing layer  40 .  
      Even when the light-transmissive substrate made of sapphire is used as the first light-transmissive member  450 R, no polarizing state of light passing through the first light-transmissive member  450 R is changed by the above construction. Further, thermal deformation of the emitting side polarizing plate  440 R can be restrained by conforming an axial direction large in thermal expansion in the first light-transmissive member  450 R and a stretched direction of the emitting side polarizing plate  440 R.  
      In the projector  1000  in accordance with exemplary embodiment 1, the second light-transmissive member  430 R is a light-transmissive substrate made of sapphire.  
      Since the light-transmissive substrate made of sapphire is very excellent in thermal conductive property, heat generated in the incident side polarizing plate  420 R can be efficiently radiated to the system exterior, and deterioration of the polarizing characteristics caused by the rise in temperature of the incident side polarizing plate  420 R can be further restrained.  
      In the projector  1000  in accordance with exemplary embodiment 1, the second light-transmissive member  430 R is arranged with respect to the incident side polarizing plate  420 R such that an optic axis of the second light-transmissive member  430 R is approximately parallel to or approximately perpendicular to a polarizing axis of the polarizing layer  20 .  
      when the light-transmissive substrate made of sapphire is used as the second light-transmissive member  430 R, no polarizing state of light passing through the second light-transmissive member  430 R is also changed by the above construction. Further, thermal deformation of the incident side polarizing plate  420 R can be restrained by conforming an axial direction large in thermal expansion in the second light-transmissive member  430 R and a stretched direction of the incident side polarizing plate  420 R.  
      In the projector  1000  in accordance with exemplary embodiment 1, a thermal conductive member  14  for transmitting heat between the first light-transmissive member  450 R and the case  10  is further arranged (see  FIG. 3A ).  
      Thus, heat generated in the emitting side polarizing plate  440 R is radiated to the case  10  through the first light-transmissive member  450 R and the thermal conductive member  14  so that heat radiating performance of the projector can be raised.  
      In the projector  1000  in accordance with exemplary embodiment 1, a thermal conductive member  16  for transmitting heat between the second light-transmissive member  430 R and the case  10  is further arranged (see  FIG. 3B ).  
      Thus, heat generated in the incident side polarizing plate  420 R is also radiated to the case  10  through the second light-transmissive member  430 R and the thermal conductive member  16  so that the heat radiating performance of the projector can be further raised.  
      For example, a metal such as aluminum, an aluminum alloy, etc. can be preferably used as materials of the thermal conductive members  14 ,  16 .  
      In the projector  1000  in accordance with exemplary embodiment 1, a cool wind flow path for cooling the first light-transmissive member  450 R and the second light-transmissive member  430 R is arranged.  
      Thus, the first light-transmissive member  450 R and the second light-transmissive member  430 R can be cooled by a cool wind from the cool wind flow path. Therefore, a rise in temperature of the first light-transmissive member  450 R and the second light-transmissive member  430 R is restrained, and heat generated in the emitting side polarizing plate  440 R and the incident side polarizing plate  420 R can be efficiently removed.  
      The projector  1000  in accordance with exemplary embodiment 1 becomes a projector of long life since deterioration of the incident side polarizing plate  420 R ( 420 G,  420 B) and the emitting side polarizing plate  440 R ( 440 G,  440 B) can be restrained.  
      The optical device  510  in accordance with exemplary embodiment 1 is one portion of the construction of the projector  1000  in accordance with exemplary embodiment 1. Effects provided by the optical device  510  in accordance with exemplary embodiment 1 are overlapped with effects provided by the projector  1000  in accordance with exemplary embodiment 1. Therefore, an explanation relating to the effects of the optical device  510  in accordance with exemplary embodiment 1 is omitted.  
      Here, in the optical device  510  in accordance with exemplary embodiment 1, the emitting side polarizing plate  440 R is a polarizing plate having the support layer  42  on only the light incident side of the polarizing layer  40 . The incident side polarizing plate  420 R is a polarizing plate having the support layer  22  on only the light incident side of the polarizing layer  20 . However, the invention is not limited to this case, but, for example, the following modifications can be performed.  
       FIGS. 4A and 4B  are views shown to explain an optical device  512  in accordance with a modified example of exemplary embodiment 1.  FIG. 4A  is a view in which the optical device  512  is seen from an upper face.  FIG. 4B  is a B-B sectional view of  FIG. 4A . In  FIGS. 4A and 4B , the same members as  FIGS. 2A and 2B  are designated by the same reference numerals and their detailed explanations are omitted.  
      In the optical device  512  in accordance with the modified example, as shown in  FIGS. 4A and 4B , an emitting side polarizing plate  442 R is a polarizing plate having a structure in which the support layer of the light emitting side is also omitted as well as the support layer of the light incident side. An incident side polarizing plate  422 R is a polarizing plate having a structure in which the support layer of the light incident side is also omitted as well as the support layer of the light emitting side.  
      An incident side polarizing plate  422 G and an emitting side polarizing plate  442 G arranged in an optical path of green light and an incident side polarizing plate  422 B and an emitting side polarizing plate  442 B arranged in an optical path of blue light are similarly polarizing plates having the above structure as well as the incident side polarizing plate  422 R and the emitting side polarizing plate  442 R arranged in the optical path of red light.  
      Thus, the optical device  512  in accordance with the modified example differs from the case of the optical device  510  in accordance with exemplary embodiment 1 in the structure of the polarizing plate used as each incident side polarizing plate and each emitting side polarizing plate. However, similar to the case of the optical device  510  in accordance with exemplary embodiment 1, the first light-transmissive member  450 R is adhered to a surface of the light incident side in the polarizing layer  40  of the emitting side polarizing plate  442 R. A surface of the light emitting side in the polarizing layer  40  of the emitting side polarizing plate  442 R is adhered to a light incident end face in the cross dichroic prism  500 . The second light-transmissive member  430 R is adhered to a surface of the light emitting side in the polarizing layer  20  of the incident side polarizing plate  422 R. A surface of the light incident side in the polarizing layer  20  of the incident side polarizing plate  422 R is adhered to a face of the light emitting side in the condenser lens  300 R. Therefore, the projector becomes a projector for further restraining that quality of a projecting image is reduced by the rise in temperature of the incident side polarizing plate and the emitting side polarizing plate in comparison with the related art.  
     Exemplary Embodiment 2  
       FIGS. 5A and 5B  are views shown to explain an optical device  514  in accordance with exemplary embodiment 2.  FIG. 5A  is a view in which the optical device  514  is seen from an upper face.  FIG. 5B  is an A-A sectional view of  FIG. 5A .  FIG. 6  is a view in which a vicinity of a polarization separating optical element  460 R is seen from a side face. In  FIGS. 5A and 5B , the same members as  FIGS. 2A and 2B  are designated by the same reference numerals, and their detailed explanations are omitted.  
      The optical device  514  in accordance with exemplary embodiment 2 basically has a construction similar to that of the optical device  510  in accordance with exemplary embodiment 1. However, as shown in  FIGS. 5A and 5B  and  6 , the optical device  514  differs from the optical device  510  in accordance with exemplary embodiment 1 in a member adhered to the light incident side of the emitting side polarizing plate.  
      Namely, in the optical device  510  in accordance with exemplary embodiment 1, the first light-transmissive members  450 R,  450 G,  450 B are respectively adhered to the faces of the light incident sides in the emitting side polarizing plates  440 R,  440 G,  440 B. In contrast to this, in the optical device  514  in accordance with exemplary embodiment 2, polarization separating optical elements  460 R,  460 G,  460 B for transmitting only linearly polarized light having an axis in a predetermined direction among lights emitted from the liquid crystal devices  410 R,  410 G,  410 B, and reflecting the other lights are adhered to faces of the light incident sides in the emitting side polarizing plates  440 R,  440 G,  440 B.  
      The polarization separating optical elements  460 R,  460 G,  460 B in the optical device  514  in accordance with exemplary embodiment 2 will be explained in detail on the basis of the construction of a member arranged in the optical path of red light among the optical paths of the respective three color lights to simplify the following explanation.  
      As shown in  FIG. 6 , the polarization separating optical element  460 R has a structure in which an XY type polarizing film  462 R having polarizing characteristics of an XY type by laminating plural films having a biaxial direction property is nipped by two glass prisms  464 R,  466 R. For example, an angle formed by a light incident face in the polarization separating optical element  460 R and the XY type polarizing film  462 R is set to 30 degrees. An unillustrated reflection preventing layer is formed on a face of the light incident side (liquid crystal device side) of the polarization separating optical element  460 R.  
      In the polarization separating optical element  460 R, polarized light reflected on the XY type polarizing film  462 R among polarized light modulated by the liquid crystal device  410 R is emitted from a side face of the polarization separating optical element  460 R as it is, or is once reflected on a light incident face of the polarization separating optical element  460 R and is then emitted from the side face of the polarization separating optical element  460 R. In this case, since this polarized light is totally reflected on the light incident face of the polarization separating optical element  460 R, a stray light level can be also reduced.  
      A light absorbing means  468 R for absorbing the polarized light reflected on the XY type polarizing film  462 R and emitted from the polarization separating optical element  460 R is arranged above the polarization separating optical element  460 R. Thus, since the light absorbing means  468 R efficiently catches light reflected on the XY type polarizing film  462 R and escaped to the system exterior, generation of the stray light in the projector can be restrained and the quality of the projecting image can be further improved. Further, since the light absorbing means  468 R is arranged above the polarization separating optical element  460 R, heat generated in the light absorbing means  468 R is escaped above the optical system by a convection current and an influence of heat given to the optical system can be minimized.  
      Thus, the optical device  514  in accordance with exemplary embodiment 2 differs from the case of the optical device  510  in accordance with exemplary embodiment 1 in the member adhered to the light incident side of the emitting side polarizing plate. However, similar to the case of the optical device  510  in accordance with exemplary embodiment 1, the polarization separating optical element  460 R is adhered to the face of the light incident side in the emitting side polarizing plate  440 R. Further, the face of the light emitting side in the emitting side polarizing plate  440 R is adhered to the light incident end face in the cross dichroic prism  500 . Therefore, the projector becomes a projector for restraining that the quality of the projecting image is reduced by the rise in temperature of the emitting side polarizing plate in comparison with the related art.  
      In the optical device  514  in accordance with exemplary embodiment 2, the linearly polarized light having an axis in a predetermined direction among light emitted from the liquid crystal device  410 R is transmitted through the polarization separating optical element  460 R and is projected by the unillustrated projection optical system  600  and is projected on the unillustrated screen SCR. On the other hand, the other light, i.e., light (a polarizing component not transmitted through the polarizing layer  40  of the emitting side polarizing plate  440 R) to be inhibited in advancement to the projection optical system  600  is reflected on the polarization separating optical element  460 R, and is escaped to the system exterior. Therefore, the light of the polarizing component not transmitted through the polarizing layer  40  of the emitting side polarizing plate  440 R among light incident to the emitting side polarizing plate  440 R is almost removed by the polarization separating optical element  460 R as a former stage. Therefore, heat generation itself in the emitting side polarizing plate  440 R is effectively restrained, and the rise in temperature of the emitting side polarizing plate  440 R can be further effectively restrained.  
      Further, the XY type polarizing film  462 R of the polarization separating optical element  460 R is a reflection type polarizing plate and is slantingly constructed with respect to the unillustrated illuminating optical axis  100   ax . Accordingly, the XY type polarizing film  462 R is slightly inferior in characteristics as an analyzer. However, a preferable image can be obtained since an amount unable to remove light unnecessary in the image by the polarization separating optical element  460 R can be reliably interrupted by the emitting side polarizing plate  440 R.  
      Namely, reliability of the device can be improved by partially bearing an operation as the analyzer and generation of heat by the polarization separating optical element  460 R and the emitting side polarizing plate  440 R.  
      The optical device  514  in accordance with exemplary embodiment 2 has a constriction similar to that of the optical device  510  in accordance with exemplary embodiment 1 except that the member adhered to the light incident side of the emitting side polarizing plate is different, Therefore, the optical device  514  has effects similar to those of the case of the optical device  510  in accordance with exemplary embodiment 1.  
     Exemplary Embodiment 3  
       FIGS. 7A and 7B  are views shown to explain a projector  1006  in accordance with exemplary embodiment 3.  FIG. 7A  is a view in which an optical device  516  is seen from an upper face.  FIG. 7B  is an A-A sectional view of  FIG. 7A . In  FIGS. 7A and 7B , the same members as  FIGS. 2A and 2B  are designated by the same reference numerals, and their detailed explanations are omitted.  
      Similar to the projector  1000  in accordance with exemplary embodiment 1, the projector  1006  in accordance with exemplary embodiment 3 is a projector having an illuminating device  100 , a color separating light guide optical system  200 , an optical device  516 , and a projection optical system  600  although its illustration is omitted. The color separating light guide optical system  200  separates an illuminating light beam from the illuminating device  100  into three color lights constructed by red light, green light and blue light, and guides the three color lights to an illuminated area. The projection optical system  600  projects light synthesized by the cross dichroic prism  500  in the optical device  516  onto a projecting face of the screen SCR, etc. The illuminating device  100 , the color separating light guide optical system  200  and the projection optical system  600  are the same as those explained in exemplary embodiment 1, and their detailed explanations are therefore omitted.  
      The optical device  516  has three liquid crystal devices  410 R,  410 G,  410 B for modulating the respective three color lights separated by the color separating light guide optical system  200  in accordance with image information. The optical device  516  also has a cross dichroic prism  500  for synthesizing the respective color lights modulated by the three liquid crystal devices  410 R,  410 G,  410 B. The optical device  516  also has three condenser lenses  300 R,  300 G,  300 B arranged on respective light incident sides of the three liquid crystal devices  410 R,  410 G,  410 B. The optical device  516  also has three incident side polarizing plates  420 R,  420 G,  420 B arranged on the respective light incident sides of the three liquid crystal devices  410 R,  410 G,  410 B. The optical device  516  also has three liquid crystal device side light-transmissive members  432 R,  432 G,  432 B adhered to faces of the light emitting sides of the three incident side polarizing plates  420 R,  420 G,  420 B. The optical device  516  also has three emitting side polarizing plates  440 R,  440 G,  440 B arranged on the respective light emitting sides of the three liquid crystal devices  410 R,  410 G,  410 B. The optical device  516  further has three liquid Crystal device side light-transmissive members  452 R,  452 G,  452 B respectively adhered to faces of the light incident sides in the three emitting side polarizing plates  440 R,  440 G,  440 B.  
      In the projector  1006  in accordance with exemplary embodiment 3, the support layer  22  in the incident side polarizing plate  420 R is arranged on the side (light incident side) opposed to the liquid crystal device  410 R in the polarizing layer  20 . The support layer  42  in the emitting side polarizing plate  440 R is arranged on the side (light emitting side) opposed to the liquid crystal device  410 R in the polarizing layer  40 .  
      Therefore, there is no generation of disturbance of molecular orientation in the support layer of the liquid crystal device side. Namely, there is no birefringence due to thermal distortion in the support layer between the polarizing layer  20  and the liquid crystal device  410 R and between the polarizing layer  40  and the liquid crystal device  410 R. Accordingly, there is no case in which polarizing characteristics as the polarizing plate are greatly reduced and quality of a projecting image is greatly reduced by a rise in temperature of the incident side polarizing plate and the emitting side polarizing plate.  
      In this case, even if the polarizing characteristics are slightly reduced in the support layer  42  of the emitting side polarizing plate  440 R by the rise in temperature, this reduction of the polarizing characteristics is not detected as light in the polarizing layer  40  of the emitting side polarizing plate  440 R. Therefore, no quality of the projecting image is greatly reduced. Further, even if the polarizing characteristics are slightly reduced in the support layer  22  of the incident side polarizing plate  420 R by the rise in temperature, this reduction of the polarizing characteristics is compensated in the polarizing layer  20  of the incident side polarizing plate  420 R, and is not detected as light in error in the polarizing layers  40  of the emitting side polarizing plate  440 R. Therefore, no quality of the projecting image is greatly reduced.  
      In the projector  1006  in accordance with exemplary embodiment 3, the liquid crystal device side light-transmissive members  432 R,  432 G,  432 B are respectively adhered to the faces of the liquid crystal device sides in the incident side polarizing plates  420 R,  420 G,  420 B. Therefore, heat generated in the incident side polarizing plates  420 R,  420 G,  420 B can be transmitted to the liquid crystal device side light-transmissive members  432 R,  432 G,  432 B. Thus, the rise in temperature of the incident side polarizing plates  420 R,  420 G,  420 B can be restrained.  
      In the projector  1006  in accordance with exemplary embodiment 3, the liquid crystal device side light-transmissive members  452 R,  452 G,  452 B are respectively adhered to the faces of the liquid crystal device sides in the emitting side polarizing plates  440 R,  440 G,  440 B. Therefore, heat generated in the emitting side polarizing plates  440 R,  440 G,  440 B can be transmitted to the liquid crystal device side light-transmissive members  452 -R,  452 G,  452 B. Thus, the rise in temperature of the emitting side polarizing plates  440 R,  440 G,  440 B can be restrained.  
      In the projector  1006  in accordance with exemplary embodiment 3, the liquid crystal device side light-transmissive members  432 R,  432 G,  432 B,  452 R,  452 G,  452 B are a light-transmissive substrate made of sapphire.  
      Since the light-transmissive substrate made of sapphire is very excellent in thermal conductive property, heat generated in the incident side polarizing plates  420 R,  420 G,  420 B and the emitting side polarizing plates  440 R,  440 G,  440 B can be efficiently radiated to the system exterior Thus, the rise in temperature of the incident side polarizing plates  420 R,  420 G,  420 B and the emitting side polarizing plates  440 R,  440 G,  440 B can be effectively restrained.  
      In the projector  1006  in accordance with exemplary embodiment 3, the liquid crystal device side light-transmissive members  432 R,  432 G,  432 B are arranged with respect to the incident side polarizing plates  420 R,  420 G,  420 B such that optical axes of the liquid crystal device side light-transmissive members  432 R,  432 G,  432 B are approximately parallel to or approximately perpendicular to a polarizing axis of the polarizing layer  20 . Further, the liquid crystal device side light-transmissive members  452 R,  452 G,  452 B are arranged with respect to the emitting side polarizing plates  440 R,  440 G,  440 B such that optical axes of the liquid crystal device side light-transmissive members  452 R,  452 G,  452 B are approximately parallel to or approximately perpendicular to a polarizing axis of the polarizing layer  40 .  
      When the light-transmissive substrate made of sapphire is used as the liquid crystal device side light-transmissive members  432 R,  432 G,  432 B,  452 R,  452 G,  452 B, no polarizing state of light passing through the liquid crystal device side light-transmissive members  432 R,  432 G,  432 B,  452 R,  452 G,  452 B is also changed by setting the above construction.  
      Further, thermal deformation of the incident side polarizing plates  420 R,  420 G,  420 B or the emitting side polarizing plates  440 R,  440 G,  440 B can be restrained by conforming an axial direction large in thermal expansion in the liquid crystal device side light-transmissive members  432 R,  432 G,  432 B,  452 R,  452 G,  452 B and a stretched direction of the incident side polarizing plates  420 R,  420 G,  420 B or the emitting side polarizing plates  440 R,  440 G,  440 B.  
      The projector  1006  in accordance with exemplary embodiment 3 becomes a projector of long life since deterioration of the incident side polarizing plates  420 R,  420 G,  420 B and the emitting side polarizing plates  440 R,  440 G,  440 B can be restrained.  
      In the projector  1006  in accordance with exemplary embodiment 3, the light-transmissive substrate made of sapphire is used as the liquid crystal device side light-transmissive members  452 R,  452 G,  452 B. However, the invention is not limited to this light-transmissive substrate, but a polarization separating optical element as explained in exemplary embodiment 2 may be also used. In this case, effects similar to those using the polarization separating optical element explained in exemplary embodiment 2 can be obtained.  
     Exemplary Embodiment 4  
       FIGS. 8A and 8B  are views shown to explain a projector  1008  in accordance with exemplary embodiment 4.  FIG. 8A  is a view in which an optical device  518  is seen from an upper face.  FIG. 8B  is an A-A sectional view of  FIG. 8A . In  FIGS. 8A and 8B , the same members as  FIGS. 7A and 7B  are designated by the same reference numerals, and their detailed explanations are omitted.  
      The unillustrated projector  1008  in accordance with exemplary embodiment 4 basically has a construction similar to that of the projector  1006  in accordance with exemplary embodiment 3, but differs from the case of the projector  1006  in accordance with exemplary embodiment 3 in that an opposite side light-transmissive member is further arranged.  
      Namely, in the projector  1008  in accordance with exemplary embodiment 4, as shown in  FIGS. 8A and 8B , opposite side light-transmissive members  470 R,  470 G,  470 B are respectively adhered to the faces (light incident faces) of sides opposed to faces of the liquid crystal device sides in the incident side polarizing plates  420 R,  420 G,  420 B. Opposite side light-transmissive members  480 R,  480 G,  480 B are respectively adhered to the faces (light emitting faces) of sides opposed to faces of the liquid crystal device sides in the emitting side polarizing plates  440 R,  440 G,  440 B.  
      Thus, the projector  1008  in accordance with exemplary embodiment 4 differs from the case of the projector  1006  in accordance with exemplary embodiment 3 in that the opposite side light-transmissive member is further arranged. However, similar to the case of the projector  1006  in accordance with exemplary embodiment 3, the support layer  22  in the incident side polarizing plate  420 R is arranged on the side (light incident side) opposed to the liquid crystal device  410 R in the polarizing layer  20 . The support layer  42  in the emitting side polarizing plate  440 R is arranged on the side (light emitting side) opposed to the liquid crystal device  410 R in the polarizing layer  40 . Therefore, there is no generation of disturbance of molecular orientation in the support layer of the liquid crystal device side. Namely, there is no birefringence due to thermal distortion in the support layer between the polarizing layer  20  and the liquid crystal device  410 R, and between the polarizing layer  40  and the liquid crystal device  410 R. Accordingly, there is no case in which polarizing characteristics as the polarizing plate are greatly reduced and quality of a projecting image is greatly reduced by the rise in temperature of the incident side polarizing plate and the emitting side polarizing plate.  
      In the projector  1008  in accordance with exemplary embodiment 4, the opposite side light-transmissive members  470 R,  470 G,  470 B are respectively adhered to light incident faces in the incident side polarizing plates  420 R,  420 G,  420 B. Therefore, heat generated in the incident side polarizing plates  420 R,  420 G,  420 B can be transmitted to the opposite side light-transmissive members  470 R,  470 G,  470 B. Thus, the rise in temperature of the incident side polarizing plates  420 R,  420 G,  420 B can be restrained.  
      Further, since no support layers  22  in the incident side polarizing plates  420 R,  420 G,  420 B are exposed to the exterior, it is possible to restrain that the support layer  22  is expanded and deformed by the rise in temperature of the incident side polarizing plates  420 R,  420 G,  420 B and the invasion of moisture from the outside air. Therefore, generation of disturbance of molecules in the support layer  22  can be restrained. As a result, a reduction in quality of the projecting image can be restrained.  
      Furthermore, the incident side polarizing plates  420 R,  420 G,  420 B are adhered to the opposite side light-transmissive members  470 R,  470 G,  470 B. Therefore, a predetermined mechanical strength can be obtained even when each of the incident side polarizing plates  420 R,  420 G,  420 B is a polarizing plate of a two-layer structure constructed by the polarizing layer  20  and one support layer  22 . In this case, a structure for nipping the incident side polarizing plates  420 R,  420 G,  420 B from both faces by the liquid crystal device side light-transmissive members  432 R,  432 G,  432 B and the opposite side light-transmissive members  470 R,  470 G,  470 B is set. Therefore, the mechanical strength can be further raised.  
      In the projector  1008  in accordance with exemplary embodiment 4, the opposite side light-transmissive members  480 R,  480 G,  480 B are respectively adhered to the light emitting faces in the emitting side polarizing plates  440 R,  440 G,  440 B. Therefore, heat generated in the emitting side polarizing plates  440 R,  440 G,  440 B can be transmitted to the opposite side light-transmissive members  480 R,  480 G,  480 B. Thus, the rise in temperature of the emitting side polarizing plates  440 R,  440 G,  440 B can be restrained.  
      Further, no support layers  42  in the emitting side polarizing plates  440 R,  440 G,  440 B are exposed to the exterior. Therefore, it is possible to restrain that the support layer  42  is expanded and deformed by the rise in temperature of the emitting side polarizing plates  440 R,  440 G,  440 B and the invasion of moisture from the outside air. Therefore, generation of disturbance of molecules in the support layer  42  can be restrained. As a result, a reduction in quality of a projecting image can be restrained.  
      Furthermore, the emitting side polarizing plates  440 R,  440 G,  440 B are adhered to the opposite side light-transmissive members  480 R,  480 G,  480 B. Therefore, even when each of the emitting side polarizing plates  440 R,  440 G,  440 B is a polarizing plate of a two-layer structure constructed by the polarizing layer  40  and one support layer  42 , a predetermined mechanical strength can be obtained. In this case, a structure for nipping the emitting side polarizing plates  440 R,  440 G,  440 B from both sides by the liquid crystal device side light-transmissive members  452 R,  452 G,  452 B and the opposite side light-transmissive members  480 R,  480 G,  480 B is set. Therefore, the mechanical strength can be further raised.  
      In the projector  1008  in accordance with exemplary embodiment 4, the opposite side light-transmissive members  470 R,  470 G,  470 B,  480 R,  480 G,  480 B are a light-transmissive substrate made of sapphire.  
      The light-transmissive substrate made of sapphire is very excellent in thermal conductive property. Therefore, heat generated in the incident side polarizing plates  420 R,  420 G,  420 B and the emitting side polarizing plates  440 R,  440 G,  440 B can be efficiently radiated to the system exterior. Thus, the rise in temperature of the incident side polarizing plates  420 R,  420 G,  420 B and the emitting side polarizing plates  440 R,  440 G,  440 B can be effectively restrained.  
      In the projector  1008  in accordance with exemplary embodiment 4, the opposite side light-transmissive members  470 R,  470 G,  470 B are arranged with respect to the incident side polarizing plates  420 R,  420 G,  420 B such that optical axes of the opposite side light-transmissive members  470 R,  470 G,  470 B are approximately parallel to or approximately perpendicular to a polarizing axis of the polarizing layer  20 . Further, the opposite side light-transmissive members  480 R,  480 G,  480 B are arranged with respect to the emitting side polarizing plates  440 R,  440 G,  440 B such that optical axes of the opposite side light-transmissive members  480 R,  480 G,  480 B are approximately parallel to or approximately perpendicular to a polarizing axis of the polarizing layer  40 .  
      When the light-transmissive substrate made of sapphire is used as the opposite side light-transmissive members  470 R,  470 G,  470 B,  480 R,  480 G,  480 B, no polarizing state of light passing through the opposite side light-transmissive members  470 R,  470 G,  470 B,  480 R,  480 G,  480 B is also changed by setting the above construction.  
      Further, thermal deformation of the incident side polarizing plates  420 R,  420 G,  420 B or the emitting side polarizing plates  440 R,  440 G,  440 B can be restrained by conforming an axial direction large in thermal expansion in the opposite side light-transmissive members  470 R,  470 G,  470 B,  480 R,  480 G  480 B, and a stretched direction of the incident side polarizing plates  420 R,  420 G,  420 B or the emitting side polarizing plates  440 R,  440 G,  440 B.  
      The projector  1008  in accordance with exemplary embodiment 4 becomes a projector of long life since deterioration of the incident side polarizing plates  420 R,  420 G,  420 B and the emitting side polarizing plates  440 R,  440 G,  440 B can be restrained.  
      The projector  1008  in accordance with exemplary embodiment 4 has a construction similar to that of the projector  1006  in accordance with exemplary embodiment 3 except that the opposite side light-transmissive member is further arranged. Therefore, the projector  1008  in accordance with exemplary embodiment 4 has effects similar to those of the case of the projector  1006  in accordance with exemplary embodiment 3.  
      In the projector  1008  in accordance with exemplary embodiment 4, the liquid crystal device side light-transmissive members  432 R,  432 G,  432 B are respectively adhered to light emitting faces in the incident side polarizing plates  420 R,  420 G,  420 B. The opposite side light-transmissive members  470 R,  470 G,  470 B are respectively adhered to light incident faces in the incident side polarizing plates  420 R,  420 G,  420 B. The liquid crystal device side light-transmissive members  452 R,  452 G,  452 B are respectively adhered to light incident faces in the emitting side polarizing plates  440 R,  440 G,  440 B. The opposite side light-transmissive members  480 R,  480 G,  480 B are respectively adhered to light emitting faces in the emitting side polarizing plates  440 R,  440 G,  440 B. However, the invention is not limited to this construction, but the following construction can be also adopted.  
      For example, in the projector  1008  in accordance with exemplary embodiment 4, the light-transmissive substrate made of sapphire is used as the liquid crystal device side light-transmissive members  452 R,  452 G,  452 B adhered to the light incident faces of the emitting side polarizing plates  440 R,  440 G,  440 B. However, a polarization separating optical element as explained in exemplary embodiment 2 may be also used instead of this light-transmissive substrate. In this case, linearly polarized light having an axis in a predetermined direction among light emitted from the liquid crystal devices  410 R,  410 G,  410 B is transmitted through the polarization separating optical element and is projected by the unillustrated projection optical system  600  and is projected on the unillustrated screen SCR. On the other hand, the other light, i.e., light (a polarizing component not transmitted through the polarizing layers  40  of the emitting side polarizing plates  440 R,  440 G,  440 B) to be inhibited in advancement to the projection optical system  600  is reflected on the polarization separating optical element and is escaped to the system exterior. Therefore, light of a polarizing component not transmitted through the polarizing layer  40  among light incident to the emitting side polarizing plates  440 R,  440 G,  440 B is almost removed by the polarization separating optical element as a former stage. Therefore, heat generation itself in the emitting side polarizing plates  440 R,  440 G,  440 B is effectively restrained. Thus, the rise in temperature of the emitting side polarizing plates  440 R,  440 G,  440 B can be further effectively restrained.  
      Further, in the projector  1008  in accordance with exemplary embodiment 4, the light-transmissive substrate made of sapphire is used as the opposite side light-transmissive members  470 R,  470 G,  470 B adhered to the light incident faces of the incident side polarizing plates  420 R,  420 G,  420 B. However, a polarization separating optical element as explained in exemplary embodiment 2 may be also used instead of this light-transmissive substrate. In this case, linearly polarized light having an axis in a predetermined direction among light emitted from the condenser lenses  300 R,  300 G,  300 B is transmitted through the polarization separating optical element, and is incident to the incident side polarizing plates  420 R,  420 G,  420 B. On the other hand, the other light, i.e., light (a polarizing component not transmitted through the polarizing layers  20  of the incident side polarizing plates  420 R,  420 G,  420 B) to be inhibited in advancement to the incident side polarizing plates  420 R,  420 G,  420 B is reflected on the polarization separating optical element and is escaped to the system exterior. Therefore, light of the polarizing component not transmitted through the polarizing layers  20  of the incident side polarizing plates  420 R,  420 G,  420 B among light emitted from the condenser lenses  300 R,  300 G,  300 B is almost removed by the polarization separating optical element as a former stage. Therefore, heat generation itself in the incident side polarizing plates  420 R,  420 G,  420 B is effectively restrained. Thus, the rise in temperature of the incident side polarizing plates  420 R,  420 G,  420 B can be further effectively restrained.  
      As the polarization separating optical element, it is possible to preferably use a polarization separating optical element constructed by a dielectric multi-layer film, a polarization separating optical element of a wire grid type formed by arraying many fine metallic thin wires, a polarization separating optical element using an XS type polarizing film having polarizing characteristics of an XY type by laminating plural films having a biaxial direction property, etc.  
      Further, in the projector  1008  in accordance with exemplary embodiment 4, the opposite side light-transmissive members  480 R,  480 G,  480 B adhered to the light emitting faces of the emitting side polarizing plates  440 R,  440 G,  440 B, and the cross dichroic prism  500  are respectively separated and arranged. However, the opposite side light-transmissive members  480 R,  480 G,  480 B may be also respectively adhered to plural light incident end faces of the cross dichroic prism  500 . In this case, heat generated in the emitting side polarizing plates  440 R,  440 G,  440 B can be transmitted to the cross dichroic prism  500  through the opposite side light-transmissive members  480 R,  480 G,  480 B. Therefore, the rise in temperature of the emitting side polarizing plates  440 R,  440 G,  440 B can be further restrained. Further, the opposite side light-transmissive members  480 R,  480 G,  480 B are adhered to the cross dichroic prism  500  comparatively large in heat capacity. Therefore, the rise in temperature of the opposite side light-transmissive members  480 R,  480 G,  480 B and the emitting side polarizing plates  440 R,  440 G,  440 B is restrained, and heat radiating performance of the projector can be raised.  
      Further, in the projector  1008  in accordance with exemplary embodiment 4, the opposite side light-transmissive members  470 R,  470 G,  470 B adhered to the light incident and emitting faces of the incident side polarizing plates  420 R,  420 G,  420 B, and the condenser lenses  300 R,  300 G,  300 B are respectively separated and arranged. However, the opposite side light-transmissive members  470 R,  470 G,  470 B may be also respectively adhered to the light emitting faces of the condenser lenses  300 R,  300 G,  300 B. In this case, heat generated in the incident side polarizing plates  420 R,  420 G,  420 B can be transmitted to the condenser lenses  300 R,  300 G,  300 B through the opposite side light-transmissive members  470 R,  470 G,  470 B. Therefore, the rise in temperature of the incident side polarizing plates  420 R,  420 G,  420 B can be further restrained. Further, the opposite side light-transmissive members  470 R,  470 G,  470 B are adhered to the condenser lenses  300 R,  300 G,  300 B comparatively large in heat capacity. Therefore, the rise in temperature of the opposite side light-transmissive members  470 R,  470 G,  470 B and the incident side polarizing plates  420 R,  420 G,  420 B is restrained, and heat radiating performance of the projector can be raised.  
     Exemplary Embodiment 5  
       FIGS. 9A and 9B  are views shown to explain a projector  1010  in accordance with exemplary embodiment 5.  FIG. 9A  is a view in which an optical device  520  is seen from an upper face.  FIG. 9B  is an A-A sectional view of  FIG. 9A . In  FIGS. 9A and 9B , the same members as  FIGS. 2A and 2B  are designated by the same reference numerals, and their detailed explanations are omitted.  
      The unillustrated projector  1010  in accordance with exemplary embodiment 5 basically has a construction similar to that of the projector  1008  in accordance with exemplary embodiment 4, but differs from the case of the projector  1008  in accordance with exemplary embodiment 4 in that the support layer in the polarizing plate is omitted.  
      Namely, in the projector  1010  in accordance with exemplary embodiment 5, as shown in  FIGS. 9A and 9B , incident side polarizing plates  424 R,  424 G,  424 B constructed by the polarizing layers  20  are used as the incident side polarizing plate, and emitting side polarizing plates  444 R,  444 G,  444 B constructed by the polarizing layers  40  are used as the emitting side polarizing plate.  
      Therefore, in accordance with the projector  1010  in accordance with exemplary embodiment 5, the incident side polarizing plates  424 R,  424 G,  424 B have no support layer. Therefore, there is no generation of disturbance of molecular orientation in the support layer. Namely, there is no birefringence due to thermal distortion in the support layer between the polarizing layers  20  and the liquid crystal devices  410 R,  410 G,  410 B. Accordingly, there is no case in which polarizing characteristics as the incident side polarizing plate are greatly reduced and quality of a projecting image is greatly reduced by a rise in temperature of the incident side polarizing plates  424 R,  424 G,  424 B.  
      In accordance with the projector  1010  in accordance with exemplary embodiment 5, no support layer is also arranged with respect to the emitting side polarizing plates  444 R,  444 G,  444 B. Therefore, there is no generation of disturbance of molecular orientation in the support layer. Namely, there is no birefringence due to thermal distortion in the support layer between the polarizing layers  40  and the liquid crystal devices  410 R,  410 G,  410 B. Accordingly, there is no case in which polarizing characteristics as the emitting side polarizing plate are greatly reduced and quality of a projecting image is greatly reduced by a rise in temperature of the emitting side polarizing plates  444 R,  444 G,  444 B.  
      Since the support layer used in the polarizing plate is normally an organic member, its coefficient of thermal conductivity is low and temperature is easily raised. Further, the support layer made of the organic member is deteriorated and disturbed in molecular orientation in a condition of high temperature and high humidity. Accordingly, the polarizing plate having the support layer made of the organic member is greatly reduced in polarizing characteristics by heat and greatly reduces the quality of the projecting image.  
      However, in accordance with the projector  1010  in exemplary embodiment 5, the incident side polarizing plates  424 R,  424 G,  424 B and the emitting side polarizing plates  444 R,  444 G,  444 B have no support layer. Therefore, such a disadvantage is not caused. Namely, the reduction in the quality of the projecting image can be restrained.  
      The projector  1010  in accordance with exemplary embodiment 5 becomes a projector of long life since deterioration of the incident side polarizing plates  424 R,  424 G,  424 B and the emitting side polarizing plates  444 R,  444 G,  444 B can be restrained.  
      The projector  1010  in accordance with exemplary embodiment 5 has a construction similar to that of the projector  1008  in accordance with exemplary embodiment 4 except that the support layer in the polarizing plate is omitted. Therefore, the projector  1010  in accordance with exemplary embodiment 5 has effects similar to those of the case of the projector  1008  in accordance with exemplary embodiment 4.  
      In the projector  1010  in accordance with exemplary embodiment 5, the liquid crystal device side light-transmissive members  432 R,  432 G,  432 B are respectively adhered to light emitting side surfaces in the polarizing layers  20  of the incident side polarizing plates  424 R,  424 G,  424 B. The opposite side light-transmissive members  470 R,  470 G,  470 B are respectively adhered to light incident side surfaces in the polarizing layers  20  of the incident side polarizing plates  424 R,  424 G,  424 B. The liquid crystal device side light-transmissive members  452 R,  452 G,  452 B are respectively adhered to light incident side surfaces in the polarizing layers  40  of the emitting side polarizing plates  444 R,  444 G,  444 B. The opposite side light-transmissive members  480 R,  480 G,  480 B are respectively adhered to light emitting side surfaces in the polarizing layers  40  of the emitting side polarizing plates  444 R,  444 G,  444 B. However, the invention is not limited to this construction, but the following construction can be also adopted.  
      For example, in the projector  1010  in accordance with exemplary embodiment 5, the light-transmissive substrate made of sapphire is used as the liquid crystal device side light-transmissive members  452 R,  452 G,  452 B adhered to the light incident side surfaces of the polarizing layers  40  of the emitting side polarizing plates  444 R,  444 G,  444 B, but a polarization separating optical element as explained in exemplary embodiment 2 may be also used instead of this light-transmissive substrate.  
      Further, in the projector  1010  in accordance with exemplary embodiment 5, the light-transmissive substrate made of sapphire is used as the opposite side light-transmissive members  470 R,  470 G,  470 B adhered to the light incident faces of the incident side polarizing plates  424 R,  424 G,  424 B, but a polarization separating optical element as explained in exemplary embodiment 2 may be also used instead of this light-transmissive substrate.  
      Further, in the projector  1010  in accordance with exemplary embodiment 5, the opposite side light-transmissive members  480 R,  480 G,  480 B adhered to the light emitting faces of the emitting side polarizing plates  444 R,  444 G,  444 B, and the cross dichroic prism  500  are respectively separated and arranged. However, the opposite side light-transmissive members  480 R,  480 G,  480 B may be also respectively adhered to plural light incident end faces of the cross dichroic prism  500 .  
      Further, in the projector  1010  in accordance with exemplary embodiment 5, the opposite side light-transmissive members  470 R,  470 G,  470 B adhered to the light incident and emitting faces of the incident side polarizing plates  424 R,  424 G,  424 B, and the condenser lenses  300 R,  300 G,  300 B are respectively separated and arranged. However, the opposite side light-transmissive members  470 R,  470 G,  470 B may be also respectively adhered to light emitting faces of the condenser lenses  300 R,  300 G,  300 B.  
      As mentioned above, the projector of the invention has been explained on the basis of each of the above exemplary embodiments. However, the invention is not limited to each of the above exemplary embodiments, but can be executed in various modes in the scope not departing from its features. For example, the following modifications can be performed.  
      The explanation has been made with respect to the examples in which the optical device of the invention is applied to the projector, but the invention is not limited to these examples. The optical device of the invention can be also applied to another optical device using polarized light.  
      In the above exemplary embodiments 1 and 2, the projector  1000  has been explained. This projector  1000  has a structure for nipping the emitting side polarizing plates  440 R,  440 G,  440 B between the first light-transmissive members  450 R,  450 G,  450 B and the cross dichroic prism  500 . Otherwise, the projector  1000  has a structure for nipping the incident side polarizing plates  420 R,  420 G,  420 B between the second light-transmissive members  430 R,  430 G,  430 B and the condenser lenses  300 R,  300 G,  300 B. However, the invention is not limited to this projector  1000 . A projector having a structure for nipping the polarizing plate between the light-transmissive member and another optical device is also included in the scope of the invention.  
      In the projector  1000  of each of the above exemplary embodiments 1 and 2, sapphire is used as both the materials of the first light-transmissive members  450 R,  450 G,  450 B and the second light-transmissive members  430 R,  430 G,  430 B, but the invention is not limited to sapphire. Crystal, quartz glass, hard glass, crystallized glass or transparent sintered glass of YAG may be also used in addition to sapphire as the materials of the first light-transmissive members  450 R,  450 G,  450 B or the second light-transmissive members  430 R,  430 G,  430 B. When crystal is used as the material of the first light-transmissive member or the second light-transmissive member, effects similar to those of the case of sapphire can be obtained. Further, when quartz glass, hard glass, crystallized glass or transparent sintered glass of YAG is used as the material of the first light-transmissive member or the second light-transmissive member, these materials are small in birefringence. Therefore, it is possible to restrain a reduction in quality of a light beam passing through the first light-transmissive member or the second light-transmissive member. Further, these materials are comparatively small in coefficient of thermal expansion. Therefore, deformation of the polarizing plate itself can be restrained by adhering the polarizing plate having a property large in extension and deformation due to heat to the first light-transmissive member or the second light-transmissive member made of such a material small in coefficient of thermal expansion. Further, another transparent glass (e.g., white plate glass, Pyrex™, etc.), YAG polycrystal, oxynitriding aluminum, etc. can be also suitably used as the materials of the first light-transmissive member and the second light-transmissive member, Namely, it is sufficient to construct the first light-transmissive members  450 R,  450 G,  450 B and the second light-transmissive members  430 R,  430 G,  430 B by inorganic materials.  
      In the above description, a suitable selection can be similarly made from the above inorganic materials with respect to the liquid crystal device side light-transmissive members  432 R,  432 G,  432 B,  452 R,  452 G  452 B or the opposite side light-transmissive members  470 R,  470 G,  470 B,  480 R,  480 G,  480 B in the projectors  1006  to  1010  in the above exemplary embodiments 3 to 5.  
      According to the projectors  1008  and  1010  in the above embodiments 4 and 5, the liquid-crystal-device-side transparent members  432 R,  432 G, and  432 B and the opposite-side transparent members  470 R,  470 G, and  470 B are located so that these optical axes are approximately in parallel with or perpendicular to the polarizing axis of the polarizing layer  20 . But, the invention is not limited this arrangement. Further, according to the projectors  1008  and  1010  in the above embodiments 4 and 5, the liquid-crystal-device-side transparent members  452 R,  452 G, and  452 B and the opposite-side transparent members  480 R,  480 G, and  480 B are located so that these optical axes are approximately in parallel with or perpendicular to the polarizing axis of the polarizing layer  40 . But, the invention is not limited this arrangement. The liquid-crystal-device-side transparent members  432 R,  432 G and  432 B and the opposite-side transparent members  470 R,  470 G, and  470 B may be located so that the optical axes of the liquid-crystal-device-side transparent members  432 R,  432 G, and  432 B may be further in parallel with or perpendicular to the polarizing axis of the polarizing layer  20 , comparing with the optical axes of the opposite-side transparent members  470 R,  470 G and  470 B. Further, the liquid-crystal-device-side transparent members  452 R,  452 G, and  452 B and the opposite-side transparent members  480 R,  480 G ad  480 B may be located so that the optical axes of the liquid-crystal-device-side transparent members  452 R,  452 G, and  452 B may be further in parallel with or perpendicular to the polarizing axis of the polarizing layer  40 , comparing with the optical axes of the opposite-side transparent members  480 R,  480 G, and  480 B.  
      The reasons of this arrangement are followings. First, the deviated amount of the optical axis of the liquid-crystal-device-side transparent members  432 R,  432 G,  432 B,  452 R,  452 G and  452 B largely affects the contrast of an image comparing with that of the optical axis of the opposite-side transparent members  470 R,  470 G,  470 B,  480 R,  480 G, and  480 B. Second, the large deviation of the optical axis of the opposite-side transparent members  470 R,  470 G,  470 B, causes the disturbance of the light beam emitted from the polarization converting element. Further; the large deviation of the optical axis of the opposite-side transparent members  480 R,  480 G,  480 B, worsens the transparent efficiency of the integration prism.  
      In order to avoid the above effects, if the affect to the contrast of a projector is constrained under 10% when a the contrast of a projector is 500:1, for example, an amount of deviation from the optical axis of the liquid-crystal-device-side transparent members  432 R,  432 G, and  432 B to the axis that is in parallel with or perpendicular to the polarizing axis of the polarizing layer  20  may be within 0.5 degrees. Further, the liquid-crystal-device-side transparent members  452 R,  452 G, and  452 B to the axis that is in parallel with or perpendicular to the polarizing axis of the polarizing layer  40  may also be within 0.5 degrees. Further, if the above effect to the light utility efficiency of a projector is constrained under 1 to 2%, for example, an amount of deviation from the optical axis of the opposite-side transparent members  470 R,  470 G, and  470 B to the axis that is in parallel with or perpendicular to the polarizing axis of the polarizing layer  20  may be within 5 degrees. Further, the opposite-side transparent members  480 R,  480 G and  480 B to the axis that is in parallel with or perpendicular to the polarizing axis of the polarizing layer  40  may also be within 5 degrees. Accordingly, an amount of deviation from the optical axes of the liquid-crystal-device-side transparent members  432 R,  432 G, and  432 B to the axis that is in parallel with or perpendicular to the polarizing axis of the polarizing layer  20  may be smaller than an amount of deviation from the optical axes of the opposite-side transparent members  470 R,  470 G and  470 B to the axis that is in parallel with or perpendicular to the polarizing axis of the polarizing layer  20 . Similarly, an amount of deviation from the optical axes of the liquid-crystal-device-side transparent members  452 R,  452 G, and  452 B to the axis that is in parallel with or perpendicular to the polarizing axis of the polarizing layer  40  may be smaller than an amount of deviation from the optical axes of the opposite-side transparent members  480 R,  480 G, and  480 B to the axis that is in parallel with or perpendicular to the polarizing axis of the polarizing layer  40 .  
      In the projectors  1008 ,  1010  of the above exemplary embodiments 4 and 5, the light-transmissive substrate made of sapphire is used as both the liquid crystal device side light-transmissive members  432 R,  432 G,  432 B,  452 R,  452 G,  452 B and the opposite side light-transmissive members  470 R,  470 G,  470 B,  480 R,  480 G  480 B, but the invention is not limited to this light-transmissive substrate. For example, one light-transmissive member among the liquid crystal device side light-transmissive member and the opposite side light-transmissive member may be a light-transmissive substrate made of quartz glass, hard glass, crystallized glass or a sintered body of cubic crystal, and the other light-transmissive member may be a light-transmissive substrate made of sapphire or crystal.  
      When the temperature of a vicinity of the polarizing plate is higher than a predetermined temperature, the liquid crystal device side light-transmissive members  432 R,  432 G,  432 B,  452 R,  452 G,  452 B are preferably a light-transmissive substrate made of sapphire or crystal from the viewpoint of reducing thermal load of the polarizing plate. The opposite side light-transmissive members  470 R,  470 G,  470 B,  480 R,  480 G,  480 B are preferably a light-transmissive substrate made of quartz glass, hard glass, crystallized glass or a sintered body of cubic crystal from the viewpoint of restraining a reduction in quality of a light beam incident to the polarizing plate, or a light beam emitted from the polarizing plate.  
      When the temperature of the vicinity of the polarizing plate is lower than the predetermined temperature, the liquid crystal device side light-transmissive members  432 R,  432 G,  432 B,  452 R,  452 G,  452 B are preferably a light-transmissive substrate made of quartz glass, hard glass, crystallized glass or a sintered body of cubic crystal from the viewpoint of restraining the reduction in quality of the light beam incident to the polarizing plate or the light beam emitted from the polarizing plate. The opposite side light-transmissive members  470 R,  470 G,  470 B,  480 R,  480 G,  480 B are preferably a light-transmissive substrate made of sapphire or crystal from the viewpoint of reducing thermal load of the polarizing plate. For example, light-transmissive sintered glass of YAG can be adopted as the sintered body of the cubic crystal.  
      In the optical device  514  in accordance with the above exemplary embodiment 2, the polarization separating optical elements  460 R,  460 G,  460 B using the XY type polarizing film having polarizing characteristics of the XY type by laminating plural films having the biaxial direction property are illustrated and explained as the polarization separating optical element, but the invention is not limited to these polarization separating optical elements  460 R,  460 G,  460 B. As the polarization separating optical element, for example, it is possible to preferably use a polarization separating optical element constructed by a dielectric multilayer film, a polarization separating optical element of a wire grid type formed by arraying many fine metallic thin films, etc.  
      In the above exemplary embodiment 1, the optical device  510  having the following structure has been explained. Namely, all of the incident side polarizing plates  420 R,  420 G,  420 B arranged on the light incident sides of the liquid crystal devices  410 R,  410 G,  410 B are respectively nipped between the second light-transmissive members  430 R,  430 G,  430 B and the condenser lenses  300 R,  300 G,  300 B. All of the emitting side polarizing plates  440 R,  440 G,  440 B arranged on the light emitting sides of the liquid crystal devices  410 R,  410 G,  410 B are respectively nipped between the first light-transmissive members  450 R,  450 G,  450 B and the cross dichroic prism  500 . However, the invention is not limited to this structure. An optical device having the following structure is also included in the scope of the invention. Namely, at least one incident side polarizing plate among the incident side polarizing plates  420 R,  420 G,  420 B is nipped between the second light-transmissive members  430 R,  430 G,  430 B and the condenser lenses  300 R,  300 G,  300 B. At least one emitting side polarizing plate among the emitting side polarizing plates  440 R,  440 G,  440 B is nipped between the first light-transmissive members  450 R,  450 G,  450 B and the cross dichroic prism  500 .  
      In the above exemplary embodiment 2, the optical device  514  having the structure for respectively nipping all of the emitting side polarizing plates  440 R,  440 G,  440 B arranged on the light emitting sides of the liquid crystal devices  410 R,  410 G,  410 B between the polarization separating optical elements  460 R,  460 G,  460 B and the cross dichroic prism  500  has been explained. However, the invention is not limited to this structure. An optical device having a structure for nipping at least one emitting side polarizing plate among the emitting side polarizing plates  440 R,  440 G,  440 B between the polarization separating optical elements  460 R,  460 G,  460 B and the cross dichroic prism  500  is also included in the scope of the invention.  
      In the above exemplary embodiment 3, the optical device  518  having the following stricture has been explained. Namely, all of the incident side polarizing plates  420 R,  420 G,  420 B arranged on the light incident sides of the liquid crystal devices  410 R,  410 G,  410 B are adhered to the liquid crystal device side light-transmissive members  432 R,  432 G;  432 B. All of the emitting side polarizing plates  440 R,  440 G;  440 B arranged on the light emitting sides of the liquid crystal devices  410 R,  410 G,  410 B are adhered to the liquid crystal device side light-transmissive members  452 R,  452 G;  452 B. However, the invention is not limited to this structure. An optical device having the following structure is also included in the scope of the invention. Namely, at least one incident side polarizing plate among the incident side polarizing plates  420 R,  420 G,  420 B is adhered to the liquid crystal device side light-transmissive members  432 R,  432 G,  432 B. At least one emitting side polarizing plate among the emitting side polarizing plates  440 R,  440 G,  440 B is adhered to the liquid crystal device side light-transmissive members  452 R,  452 G,  452 B.  
      In the above exemplary embodiment 4, the optical device  518  having the following structure has been explained. Namely, all of the incident side polarizing plates  420 R,  420 G,  420 B arranged on the light incident sides of the liquid crystal devices  410 R,  410 G,  410 B are respectively nipped between the liquid crystal device side light-transmissive members  432 R,  432 G,  432 B and the opposite side light-transmissive members  470 R,  470 G,  470 B. All of the emitting side polarizing plates  440 R,  440 G,  440 B arranged on the light emitting sides of the liquid crystal devices  410 R,  410 G,  410 B are respectively nipped between the liquid crystal device side light-transmissive members  452 R,  452 G,  452 B and the opposite side light-transmissive members  480 R,  480 G,  480 B. However, the invention is not limited to this structure. An optical device having the following structure is also included in the scope of the invention. Namely, at least one incident side polarizing plate among the incident side polarizing plates  420 R,  420 G,  420 B is nipped between the liquid crystal device side light-transmissive members  432 R,  432 G,  432 B and the opposite side light-transmissive members  470 R,  470 G,  470 B. At least one emitting side polarizing plate among the emitting side polarizing plates  440 R,  440 G,  440 B is nipped between the liquid crystal device side light-transmissive members  452 R,  452 G,  452 B and the opposite side light-transmissive members  480 R,  480 G,  480 B.  
      in the above exemplary embodiment 5, the optical device  520  having the following structure has been explained. Namely, all of the incident side polarizing plates  424 R,  424 G,  424 B arranged on the light incident sides of the liquid crystal devices  410 R,  410 G,  410 B are respectively nipped between the liquid crystal device side light-transmissive members  432 R,  432 G,  432 B and the opposite side light-transmissive members  470 R,  470 G,  470 B. All of the emitting side polarizing plates  444 R,  444 G,  444 B arranged on the light emitting sides of the liquid crystal devices  410 R,  410 G,  410 B are respectively nipped between the liquid crystal device side light-transmissive members  452 R,  452 G  452 B and the opposite side light-transmissive members  480 R,  480 G,  480 B. However, the invention is not limited to this structure. An optical device having the following structure is also included in the scope of the invention. Namely, at least one incident side polarizing plate among the incident side polarizing plates  424 R,  424 G,  424 B is nipped between the liquid crystal device side light-transmissive members  432 R,  432 G,  432 B and the opposite side light-transmissive members  470 R,  470 G,  470 B. At least one emitting side polarizing plate among the emitting side polarizing plates  444 R,  444 G,  444 B is nipped between the liquid crystal device side light-transmissive members  452 R,  452 G,  452 B and the opposite side light-transmissive members  480 R,  480 G,  480 B.  
      In a modified example of the above exemplary embodiment 1, when the polarizing plate (polarizing layer  20 ) having a structure for also omitting the support layer of the light emitting side as well as the support layer of the light incident side is adhered to the first light-transmissive member and the cross dichroic prism, it is preferable that the polarizing layer  20  is first adhered to one of the first light-transmissive member and the cross dichroic prism through an adhesive, and heat treatment is then taken and the polarizing layer  20  is then adhered to the other. Further, when the polarizing layer  20  is adhered to the second light-transmissive member and the condenser lens, it is preferable that the polarizing layer is first adhered to one of the second light-transmissive member and the condenser lens through an adhesive, and heat treatment is then taken and the polarizing layer is then adhered to the other. In this case, in the heat treatment, a leaving operation is performed for 0.5 to 10 hours in an environment of 80 degrees to 110 degrees centigrade. Thus, since initial contraction due to heat of polarizing layer  20  is performed, damage of the polarizing layer  20  due to thermal stress can be prevented even when the polarizing layer  20  is assembled into the projector  1000  and light is irradiated and heat is applied.  
      In the above exemplary embodiment 5, when the polarizing layer  20  having no support layer is adhered to the liquid crystal device side light-transmissive member and the opposite side light-transmissive member; it is preferable that the polarizing layer  20  is first adhered to one of the liquid crystal device side light-transmissive member and the opposite side light-transmissive member through an adhesive and heat treatment is then taken and the polarizing layer  20  is then adhered to the other. In this case, in the heat treatment, a leaving operation is performed for 0.5 to 10 hours in an environment of 80 degrees to 110 degrees centigrade. Thus, since initial contraction due to heat of polarizing layer  20  is performed, damage of the polarizing layer  20  due to thermal stress can be prevented even when the polarizing layer  20  is assembled into the projector  1010  and light is irradiated and heat is applied.  
      In the projector  1000  of the above exemplary embodiment 1, the light source device  110  having the elliptical face reflector  114 , the light emitting tube  112  having a light emitting center near a first focal point of the elliptical face reflector  114 , and the concave lens  118  is used as a light source device. However, the invention is not limited to this light source device, but it is possible to preferably use a light source device having a parabolic reflector and a light emitting tube having a light emitting center near a focal point of the parabolic reflector.  
      In the projector  1000  of the above exemplary embodiment 1, the case for arranging the auxiliary mirror  116  as a reflecting means in the light emitting tube  112  has been illustrated and explained. However, the invention is not limited to this case, but can be also applied to a structure in which no auxiliary mirror is arranged in the light emitting tube.  
      In the projector  1000  of the above exemplary embodiment 1, the lens integrator optical system constructed by the lens array is used as a light uniforming optical system. However, the invention is not limited to this optical system, but a rod integrator optical system constructed by a rod member can be also preferably used.  
      In each of the above exemplary embodiments, the projector using the three liquid crystal devices  410 R,  410 G,  410 B has been illustrated and explained. However, the invention is not limited to this projector, but can be also applied to a projector using one, two, or four or more liquid crystal devices.  
      The invention can be also used in a case applied to a front projecting type projector for projecting a projecting image from its observing side, and a case applied to a rear projecting type projector for projecting the projecting image from the side opposed to the observing side.  
      The priority applications Numbers JP2005-193440, JP2006-047871, JP2006-047872, JP2006-047873, JP2006-121650, JP2006-121651, JP20066-121652, 2006-172244, JP2006-172245 and JP2006-172246 upon which this patent application is based is hereby incorporated by reference.  
      While this invention has been described in conjunction with the specific embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art. Accordingly, preferred embodiments of the invention as set forth herein are intended to be illustrative, not limiting. There are changes that may be made without departing from the spirit and scope of the invention.