JP2002318340A - Prism unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a prism unit which has components with prolonged life by improving ventilation, is easily assembled, adjusted and maintained and is low-cost. SOLUTION: The prism unit consists of a prism 2, three pieces of liquid crystal mounting plates 5 to mount liquid crystal panels 4, an upper side frame 6 to be fixed to the upper surface of the prism 2, a lower side frame 7 to be fixed to the base of the prism 2 and a pedestal 3 holding the prism 2 and the lower side frame 7 from beneath and being attached to a specified position inside a liquid crystal projector. The upper parts of the liquid crystal mounting plates 5 and the upper side frame 6 and the lower parts of the liquid crystal mounting plates 5 and the lower side frame 7 are respectively provided with parts 9 fixing the liquid crystal mounting plates to respectively connect and fix themselves. Upper side opening parts 6b are provided on the upper side frame 6 in specified positions between the prism 2 and the liquid crystal mounting plates 5. At the same time, polarization filter parts 10 with polarization filters 8 are provided which are freely attachable to and detachable from the upper side opening parts 6b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a prism unit mounted on a liquid crystal projector, and more particularly, to a prism unit which can be easily assembled and maintained, is easy to maintain, and is inexpensive.

[0002]

2. Description of the Related Art Conventionally, there is a prism unit mounted on a liquid crystal projector as shown in FIG. 4, a prism unit 51 has a prism 52 fixed on a pedestal 53 by bonding or the like, and a frame 56 is mounted on the pedestal 53. A liquid crystal mounting plate 55 is mounted on each of the three surfaces of the frame 56, and a liquid crystal panel 54 is mounted on the liquid crystal mounting plate 55, respectively. Prism 52
A polarizing filter 58 is bonded to each surface corresponding to the liquid crystal panel 54. By the way, with the recent increase in the brightness of the liquid crystal projector, the temperature rise due to the absorption of the light energy by the polarizing filter 58 becomes remarkable due to the power up of the light from the light source, and the polarizing filter 58 burns for a long time. The problem that there is, has become apparent. Conventionally, a rise in the temperature of the polarizing filter has not been a serious problem. Therefore, no particular countermeasure has been taken into consideration. Even if the polarizing filter 58 is burned and deteriorates, it is assumed that the polarizing filter 58 is adhered to the prism 52 or the like. There was also a maintenance problem that replacement was not possible. Polarizing filter 5
There is also a method of bonding 8 to the liquid crystal panel 54, but there is a similar problem. As described above, the method of bonding the polarizing filter 58 to the prism 52 or the liquid crystal panel 54 has a problem that maintenance and inconvenience such as replacement of the polarizing filter 58 and re-use of the prism 52 and the liquid crystal panel 54 are required. I was holding it.

In addition, as in the prior art, the prism unit 5
The frame 56 is mounted on the base 53 as
The method of attaching the liquid crystal panel 54 to the liquid crystal panel 6 is to assemble and adjust the prism unit 51 and fix the prism unit 51 to a chassis or the like of the liquid crystal projector. However, there is a problem that the registration may gradually shift, and readjustment is required. In particular, as compared with the assembly adjustment of the prism unit 51, the assembly adjustment of the liquid crystal projector is troublesome because other optical components are entangled in the periphery and are troublesome. As described above, it is hoped that a prism unit having a longer life as a prism unit, easier to assemble and adjust, will not require adjustment once the liquid crystal projector is assembled after adjustment, and will be easier to maintain and cheaper. Was rare.

[0004]

SUMMARY OF THE INVENTION In view of the above-mentioned problems, the present invention improves ventilation and extends the life of components, simplifies assembly adjustment, facilitates maintenance, and is inexpensive. The purpose is to provide a prism unit.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention combines light beams of three primary colors, red, green and blue, which are respectively incident from three horizontal incident surfaces, and combines them in another one direction. A dichroic prism (hereinafter, referred to as a prism) that radiates from the radiation side surface, three liquid crystal mounting plates for mounting a liquid crystal panel, and the liquid crystal mounting plate disposed outside of the prism at a predetermined distance from the incident side surface. To set up,
An upper frame having an area larger than the upper surface of the prism having an upper fixing portion fixed to the upper surface of the prism, and having an area larger than the bottom surface of the prism having a lower fixing portion opposed to the upper frame and fixed to the bottom surface of the prism. A lower frame, a polarizing filter provided between the prism and the liquid crystal panel, and a pedestal that supports the prism and the lower frame from below and is attached to a predetermined position inside a liquid crystal projector; The upper part of the mounting plate and the upper frame, and the lower part of the liquid crystal mounting plate and the lower frame respectively have a liquid crystal mounting plate fixing part for connecting and fixing each other, and the prism of the upper frame and the prism An upper opening is provided at a predetermined position between the liquid crystal mounting plate and the upper opening. And removable from parts, provided with a polarizing filter sections having the polarizing filter.

The lower frame has a lower opening at a position opposite to the upper opening, and the polarizing filter is provided between the polarizing filter and the prism, and between the polarizing filter and the liquid crystal mounting plate. And a predetermined space between them, and a ventilation path is formed to ventilate from the lower opening to the upper opening and cool the polarizing filter unit from front and rear.

The upper surface of the prism and the upper fixing portion of the upper frame, and the bottom surface of the prism and the lower fixing portion of the lower frame are bonded, respectively.

The pedestal has a prism fixing portion for fixing the bottom surface of the prism on the upper surface, and the prism fixing portion is adhered and fixed to the bottom surface of the prism at a predetermined position not in contact with the lower frame. Is done.

The upper fixing portion is formed by projecting a contact surface of a predetermined size in contact with the upper surface of the prism of the upper frame into a column having a predetermined height, and the lower fixing portion is formed of the lower frame. A contact surface of a predetermined size in contact with the bottom surface of the prism is formed to protrude in a columnar shape having a predetermined height, and the upper fixing part and the lower fixing part are the upper frame and the lower frame. , Respectively.

The prism fixing portion is formed by projecting a contact surface of a predetermined size in contact with the bottom surface of the prism of the pedestal into a column having a predetermined height, and a plurality of the prism fixing portions are provided on the pedestal.

The height of the prism fixing part is higher than the height of the lower fixing part.

The lower frame has a through hole through which the prism fixing portion penetrates and which is larger than the outer periphery of the prism fixing portion.

[0013] The upper frame is formed of a plate material, and has a side surface formed by folding a predetermined portion corresponding to the incident side surface outside the prism upward, respectively.

[0014] The lower frame is made of a plate material and has a side surface formed by folding a predetermined portion corresponding to the incident side surface outside the prism downward.

[0015] The liquid crystal mounting plate fixing portion includes a locking portion provided outside each side surface of the upper frame and the lower frame, and the locking portion provided at a corresponding position of the liquid crystal mounting plate. And an engaging portion for fixing the liquid crystal mounting plate by engaging with the liquid crystal mounting plate.

The engaging portion comprises a projection provided on the outside of the side surface of the upper frame and the lower frame, and the engaging portions are provided at respective positions corresponding to the engaging portion of the liquid crystal mounting plate. An insertion hole through which the projection is inserted.

The insertion hole is a projection hole.

The projection and the insertion hole are bonded and fixed in a predetermined state in which the projection is inserted through the insertion hole.

The projections extend outward on respective side surfaces of the upper frame and the lower frame, and are integrally formed on the upper frame and the lower frame, respectively.

The locking portion is provided on the liquid crystal mounting plate, and the engaging portion is provided on a side surface of the upper frame and the lower frame.

The polarizing filter section is made of a glass plate on which the polarizing filter is mounted.

The lower frame 7 has a stopper for supporting the lower portion of the glass plate, and a guide groove for preventing the lower portion of the glass plate from shifting or tilting in the front-rear direction.

The polarizing filter section includes a glass plate on which the polarizing filter is mounted, and a polarizing plate for mounting the glass plate.

The polarization mounting plate is formed of an aluminum member.

The polarized light mounting plate has an upper portion with a finger hook for manually inserting and removing the polarized light mounting plate.

The polarized light mounting plate has downwardly projecting protrusions at the left and right lower portions, respectively, and is inserted into the lower frame at a position corresponding to the convex portion, and the front and rear of the polarized light mounting plate are inserted. A guide hole is provided to prevent deviation and inclination of the direction.

The opening of the upper frame is provided with cutout holes at both ends in the longitudinal direction for preventing the glass plate or the polarizing plate from shifting or tilting in the front-rear direction.

The upper frame includes a holding plate for preventing the glass plate or the polarizing plate from dropping upward.

The holding plate is formed integrally with a locking piece protruding to the left and right outside, and is engaged with the locking piece at a position corresponding to the locking piece on a side surface of the upper frame to thereby hold the holding plate. Is provided.

The holding plate is formed of a spring member.

The pedestal is provided with a screw insertion hole for inserting a fixing screw for screwing the pedestal to a predetermined position of the liquid crystal projector for fixing.

The pedestal is provided with a positioning hole for inserting a positioning jig, a guide pin and the like for positioning the pedestal at a predetermined position of the liquid crystal projector.

The pedestal is provided with the screw insertion hole at a portion extending outward on the radiation side of the prism, and the screw insertion hole is formed so that a fixing screw can be inserted from above, and the upper frame is formed. And the lower frame are provided with cutouts that allow the fixing screws to be inserted into the screw insertion holes from above with a tool such as a screwdriver and to be screwed.

[0034]

FIG. 1 is an exploded perspective view for explaining an embodiment of a prism unit according to the present invention. FIG.
3A and 3B are side sectional views of a main part of an embodiment of the prism unit of the present invention. 3A is a top view and FIG. 3B is a rear view of the prism unit. An embodiment of the present invention will be described with reference to FIGS. The basic configuration of the prism unit 1 of the present invention is to combine the light beams of the three primary colors of red (R), green (G), and blue (B), which are respectively incident from the horizontal three side surfaces, and emit the light in the other one direction. A dichroic prism 2 radiating from the side surface, three liquid crystal mounting plates 5 for mounting a liquid crystal panel 4, and the liquid crystal mounting plates 5 are arranged at corresponding positions outside the horizontal three-side incidence side surface of the prism 2. And a polarizing filter section 10 having a polarizing filter 8 provided between the prism 2 and the liquid crystal panel 4, and an upper frame 6 above the prism 2, a lower frame 7 below the prism 2, A pedestal 3 is supported from below and attached to a predetermined position inside the liquid crystal projector.

The upper frame 6 has an area larger than the upper surface of the prism 2 and has an upper fixing portion 6a for fixing to the upper surface of the prism 2. The bottom surface of the upper fixing portion 6a and the upper surface of the prism 2 are fixed. Have been. Lower frame 7
Has a lower fixing portion 7a for fixing to the bottom surface of the prism 2 having an area larger than the bottom surface of the prism 2,
The upper surface of the lower fixing portion 7a and the bottom surface of the prism 2 are fixed. The liquid crystal mounting plate 5 includes a window hole 5a for transmitting a light beam from the liquid crystal panel 4 and three mounting holes 45b for inserting screws for screwing the liquid crystal panel 4 therethrough. The upper part of the liquid crystal mounting plate 5, the upper frame 6, and the liquid crystal mounting plate 5
And the lower frame 7 are respectively provided with a liquid crystal mounting plate fixing portion 9 for connecting and fixing each other, and the liquid crystal mounting plate 5 is separated from the incident side surface of the prism 2 in three horizontal directions by a predetermined distance. The liquid crystal mounting plate 5 and the upper frame 6 and the liquid crystal mounting plate 5 and the lower frame 7 are fixed at predetermined positions. An upper opening 6b is provided at a predetermined position between the prism 2 of the upper frame 6 and the liquid crystal mounting plate 5, and a polarizing filter unit 10 having a polarizing filter 8 which is detachable from the upper opening 6b is provided. .

As shown in FIG. 2A, the upper surface of the prism 2 and the upper fixing portion 6a of the upper frame 6, and the bottom surface of the prism 2 and the lower fixing portion 7a of the lower frame 7 are bonded to each other. . The top and bottom surfaces of the prism 2 are finished with predetermined accuracy, and the upper frame 6 and the lower frame 7
Is positioned and bonded using a jig,
Each mounting error is small. By dividing the upper frame 6 and the lower frame 7 and bonding them to the prism 2, a vertical connecting member for connecting the upper frame 6 and the lower frame 7 is unnecessary, and the upper frame 6 and the lower frame 7 are not required. No black painting with 7 is required.
Generally, the vertical connecting member close to the prism 2 causes irregular reflection due to light leaking from the optical path and requires black painting. However, the upper frame 6 and the lower frame 7 are parallel to the optical path, There is no. Since the other members are not arranged close to the prism 2, the black coating is unnecessary and the cost is low. The pedestal 3 is provided with a prism fixing portion 3a for fixing the bottom surface of the prism 2 on the upper surface, and the prism fixing portion 3a is adhered and fixed to the bottom surface of the prism 2 at a predetermined position not in contact with the lower frame 7. .
By separating the lower frame 7 and the pedestal 3 and bonding them independently to the prism 2, distortion of screw tightening when the pedestal 3 is screwed to the chassis or the like affects the upper frame 6 and the lower frame 7. There is no. As described above, since the upper frame 6, the lower frame 7, and the pedestal 3 are independently bonded to the prism 2, a compact configuration with high mounting accuracy is obtained.

As shown in FIG. 2A, the upper fixing portion 6a
Is formed by projecting a contact surface of a predetermined size in contact with the upper surface of the prism 2 of the upper frame 6 into a column shape having a predetermined height, and the lower fixing portion 7a is in contact with the bottom surface of the prism 2 of the lower frame 7. A contact surface having a predetermined size is formed by projecting into a column shape having a predetermined height, and a plurality of upper fixing portions 6a and lower fixing portions 7a are provided on the upper frame 6 and the lower frame 7, respectively. Since the contact surface is formed by projecting into a columnar shape with a relatively small area, an extra escape area for the adhesive is generated, and the adhesive is uniformly applied to the adhesive surface. In addition, by providing three contact surfaces, the prism is provided. 2 and the upper frame 6 and the lower frame 7 can be kept parallel. The prism fixing portion 3a is also formed by projecting a contact surface of a predetermined size in contact with the bottom surface of the prism 2 of the pedestal 3 into a column having a predetermined height.
A plurality of pedestals 3 are provided to ensure parallelism after bonding. The height of the prism fixing portion 3a is higher than the height of the lower fixing portion 7a, and the lower frame 7 has a through hole larger than the outer periphery of the prism fixing portion 3a so that the prism fixing portion 3a penetrates. 3 are securely separated from each other so as to be independently adhered to each other. Since the prism fixing portion 3a and the lower fixing portion 7a have such a structure and are completely separated from each other and adhered, no distortion of the pedestal 3 is applied to the upper frame 6 and the lower frame 7.

The upper frame 6 is made of a plate material, and has a side surface formed by folding a predetermined portion corresponding to the incident side surface outside the prism 2 upward.
The lower frame 7 is made of a plate material, and
Predetermined portions corresponding to the outer incident side surfaces are respectively folded back to form side surfaces. Upper frame 6
The lower frame 7 and the lower frame 7 are formed in a substantially box-like shape with two sides open in this way, thereby ensuring sufficient strength despite being compact.

The liquid crystal panel 4 and the liquid crystal mounting plate 5 are screwed together with screws through three mounting holes 45b. The screwing allows adjustment of the horizontal inclination of the liquid crystal panel 4 and facilitates replacement. The liquid crystal mounting plate 5, the upper frame 6, and the lower frame 7 are fixed to each other by locking portions 9a provided outside the respective side surfaces of the upper frame 6 and the lower frame 7, and the corresponding positions of the liquid crystal mounting plate 5. The liquid crystal mounting plate fixing portion 9 includes an engaging portion 9b for fixing the liquid crystal mounting plate 5 by engaging with the locking portion 9a provided in the above. The locking portion 9a of the liquid crystal mounting plate fixing portion 9 includes projections provided on the outer sides of the upper frame 6 and the lower frame 7, and the engaging portion 9b is formed of the liquid crystal mounting plate 5.
The projections provided at the respective positions corresponding to the locking portions 9a are insertion holes for insertion, and the insertion holes are projection holes projecting in the opposite direction to the liquid crystal mounting plate 5. The projection and the insertion hole are adhered and fixed in a predetermined state in which the projection has passed through the insertion hole. The adhesive used is an ultraviolet-curable adhesive and is positioned using a jig. Since the adhesive is adhered so as to fill the protruding holes, mutual attachment errors are small and the adhesive can be securely adhered. The projections extend outwardly on the respective side surfaces of the upper frame 6 and the lower frame 7, and are compactly formed integrally with the upper frame 6 and the lower frame 7. The locking portion 9a and the engaging portion 9b may be interchanged, and the locking portion 9a may be provided on the liquid crystal mounting plate 5, and the engaging portion 9b may be provided on the side surfaces of the upper frame 6 and the lower frame 7.

The polarizing filter section 10 comprises a glass plate 8a to which the polarizing filter 8 is bonded, and a polarizing plate 10a to which the glass plate 8a is bonded. The polarized light mounting plate 10a includes a finger hook 10b for inserting and removing the polarized light mounting plate 10a by hand. The polarized light mounting plate 10a is provided with convex portions 10c protruding downward at the left and right lower portions, respectively, and is inserted into the position corresponding to the convex portion 10c of the lower frame 7 by inserting the convex portion 10c in the front-rear direction of the polarized light mounting plate 10a. It has a guide hole 7c for preventing displacement and inclination. Upper frame 6
Has an upper opening 6b that allows the polarizing filter unit 10 to be detachable from above, and the lower frame 7 includes an upper opening 6b.
And a lower opening 7b at a position facing the prism 2, the polarizing filter 10 is provided between the polarizing filter 10 and the prism 2,
And a predetermined space between the polarizing filter section 10 and the liquid crystal mounting plate 5 to form a ventilation path 11 for ventilating the lower opening section 7b to the upper opening section 6b and cooling the polarizing filter section 10 from front and rear. (Fig. 2). The upper opening 6b of the upper frame 6 has a polarizing mounting plate 10a at both ends in the longitudinal direction.
A notch 6d for preventing the front-to-rear shift and inclination of the notch.

As described above, since the ventilation passages 11 are formed before and after the polarization mounting plate 10a, the temperature of the polarization filter unit 10 can be lowered and the life can be extended. In particular, in the case of a high-brightness liquid crystal projector, ventilation is performed by a fan from below on the prism unit 1, so that the polarization filter unit 10 can be cooled more effectively. In addition, since a finger hook 10b is provided above the polarization mounting plate 10a and made detachable, assembly work and maintenance are also facilitated. Further, by fitting the lower convex portion 10c of the polarization mounting plate 10a and the guide hole 7c of the lower frame 7, it is possible to prevent a shift and a tilt in the front-rear direction. In addition, the polarizing filter unit 1
0 may be a compact one in which the polarizing plate 10a is omitted and the polarizing plate 8 is bonded to the glass plate 8a. In this case, the lower frame 7 includes a stopper 7e for supporting the lower portion of the glass plate 8a, and a guide groove 7d for preventing the lower portion of the glass plate 8a from shifting or tilting in the front-rear direction. Support and hold. The cost can be reduced by using the glass plate 8a with a polarizing filter. FIG. 1 shows an example in which only the red (R) system can support the glass plate 8a with a polarizing filter.

The upper frame 6 includes a holding plate 12 for preventing the polarization mounting plate 10a from dropping upward, and the holding plate 12 is formed by a spring member. The holding plate 12 is formed integrally with locking pieces protruding outward in the left and right directions, and has locking pieces 12 at positions corresponding to the locking pieces 12a on the side surface of the upper frame 6.
and a retaining hole 6e for retaining the presser plate 12 by engaging with the retaining plate 12a. Remove the locking piece 12a from the engaging hole 6e and press the holding plate 1
2 is removed, the polarization mounting plate 10a or the polarization filter 8 is removed.
The attached glass plate 8a can also be easily removed. As described above, the polarizing filter unit 10 can be manually attached and detached, and no tools are required for assembling, replacing, cleaning, and the like.

The pedestal 3 is provided with a screw insertion hole 3b for inserting a fixing screw for screwing the pedestal 3 to a predetermined position of the liquid crystal projector and fixing the same. The pedestal 3 has a positioning hole 3c through which a positioning jig or a guide pin is inserted for positioning the pedestal 3 at a predetermined position of the liquid crystal projector.
Is provided. A plurality of positioning holes 3c may be provided on the bottom surface of the pedestal 3. The pedestal 3 is provided with a screw insertion hole 3b at a portion extending outward from the radiation side surface of the prism 2, and the screw insertion hole 3b is formed so that a fixing screw can be inserted from above, and the upper frame 6 and the lower frame 7 means that the fixing screw is inserted from above with a tool such as a screwdriver into the screw insertion hole 3.
and a cut-out portion which can be screwed by being inserted through b. Thereby, when mounting the prism unit 1 to the liquid crystal projector, the pedestal 3 can be easily mounted by the driver from above (FIG. 3). With the configuration as described above, it is possible to obtain a compact prism unit 1 with good ventilation, easy to assemble and adjust and does not require re-adjustment, as shown in FIGS. 3 (a) and 3 (b).

[0044]

The present invention is embodied in the manner described above, and has the following effects. A dichroic prism that combines light beams of the three primary colors of red, green, and blue respectively incident from three horizontal incident surfaces, and emits the light from the other one emitting surface, and three liquid crystal mounting plates for mounting a liquid crystal panel An upper frame having an area larger than the upper surface of the prism, the upper frame having an upper fixing portion fixed to the upper surface of the prism for disposing the liquid crystal mounting plate on the outer side at a predetermined distance from the incident side surface of the prism; A lower frame having a larger area than the bottom surface of the prism having a lower fixing portion opposed to the frame and fixed to the bottom surface of the prism, a polarizing filter provided between the prism and the liquid crystal panel, and supporting the prism and the lower frame from below, It consists of a pedestal attached to a predetermined position inside the liquid crystal projector, the upper part of the liquid crystal mounting plate and the upper frame, and The lower and the lower frame of the crystal mounting plate, includes a liquid crystal mounting plate fixing portion for fixedly connected to each other, respectively,
An upper opening is provided at a predetermined position between the prism of the upper frame and the liquid crystal mounting plate, and a polarizing filter portion having a polarizing filter that is detachable from the upper opening is provided. It is possible to provide a prism unit that can extend the service life and can simplify the assembly adjustment, can be easily maintained, and is inexpensive.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view for explaining one embodiment of a prism unit of the present invention.

FIGS. 2A and 2B are cross-sectional views of main parts of the AA, and FIG. 2B are cross-sectional views of main parts of a BB in an embodiment of the prism unit of the present invention.

FIG. 3A is a top view and FIG. 3B is a rear view in one embodiment of the prism unit of the present invention.

FIG. 4 is an exploded perspective view of a conventional prism unit.

[Explanation of symbols]

 Reference Signs List 1 prism unit 2 prism (dichroic prism) 3 pedestal 3a prism fixing portion 3b screw insertion hole 3c positioning hole 4 liquid crystal panel 5 liquid crystal mounting plate 5a window hole 6 upper frame 6a upper fixing portion 6b upper opening 6c notch 6d notch 6e Engagement hole 7 Lower frame 7a Lower fixing portion 7b Lower opening 7c Guide hole 7d Guide groove 7e Stopper 8 Polarizing filter 8a Glass plate 9 Liquid crystal mounting plate fixing portion 9a Locking portion 9b Engaging portion 10 Polarizing filter portion 10a Polarizing mounting Plate 10b Finger part 10c Convex part 11 Ventilation path 12 Holding plate 12a Locking piece 45b Mounting hole

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03B 33/12 G02B 7/18 A

Claims (29)

[Claims] 1. A dichroic prism (hereinafter, referred to as a prism) that combines light beams of three primary colors of red, green, and blue that respectively enter from three horizontal incident side surfaces and emits light from another one-directional emitting side surface, and a liquid crystal. Three liquid crystal mounting plates for mounting a panel, and a liquid crystal mounting plate for arranging the liquid crystal mounting plate on the outside of the prism at a predetermined distance from the incident side surface,
An upper frame having an area larger than the upper surface of the prism having an upper fixing portion fixed to the upper surface of the prism, and having an area larger than the bottom surface of the prism having a lower fixing portion opposed to the upper frame and fixed to the bottom surface of the prism. A lower frame, a polarizing filter provided between the prism and the liquid crystal panel, and a pedestal that supports the prism and the lower frame from below and is attached to a predetermined position inside a liquid crystal projector; The upper part of the mounting plate and the upper frame, and the lower part of the liquid crystal mounting plate and the lower frame respectively have a liquid crystal mounting plate fixing part for connecting and fixing each other, and the prism of the upper frame and the prism An upper opening is provided at a predetermined portion between the liquid crystal mounting plate and the upper portion. And removable from the mouth portion, a prism unit, characterized in that a polarizing filter sections having the polarizing filter. 2. The lower frame has a lower opening at a position facing the upper opening, and the polarizing filter unit is provided between the polarizing filter unit and the prism, and between the polarizing filter unit and the liquid crystal. 2. A ventilation path is provided between the mounting plate and the mounting plate, and a ventilation path is formed to ventilate from the lower opening to the upper opening and cool the polarizing filter unit from front and rear. Prism unit. 3. The method according to claim 1, wherein an upper surface of the prism and the upper fixing portion of the upper frame are bonded to each other, and a bottom surface of the prism and the lower fixing portion of the lower frame are bonded to each other. The prism unit according to 1. 4. The pedestal includes a prism fixing portion for fixing a bottom surface of the prism on an upper surface, and the prism fixing portion adheres to a bottom surface of the prism at a predetermined position not in contact with the lower frame. The prism unit according to claim 1, wherein the prism unit is fixed. 5. The upper fixing part is formed by projecting a contact surface of a predetermined size in contact with an upper surface of the prism of the upper frame into a column shape having a predetermined height, and the lower fixing part is A contact surface of a predetermined size in contact with the bottom surface of the prism of the lower frame is formed by protruding into a column shape having a predetermined height, and the upper fixing portion and the lower fixing portion are formed of the upper frame and the lower portion. A plurality of frames are provided on the frame.
5. The prism unit according to any one of items 1 to 4. 6. The prism fixing portion is formed by projecting a contact surface of a predetermined size in contact with the bottom surface of the prism of the pedestal into a column shape having a predetermined height, and a plurality of the prism fixing portions are provided on the pedestal. The prism unit according to claim 1, wherein: 7. The prism unit according to claim 6, wherein the height of the prism fixing part is higher than the height of the lower fixing part. 8. The prism unit according to claim 4, wherein the lower frame includes a through hole through which the prism fixing portion penetrates and is larger than an outer periphery of the prism fixing portion. 9. The apparatus according to claim 1, wherein the upper frame is made of a plate material, and a predetermined portion corresponding to the incident side surface outside the prism is folded upward to form a side surface. The prism unit according to 1. 10. The lower frame is made of a plate material and has a side surface formed by folding a predetermined portion corresponding to the incident side surface outside the prism downward, respectively. The prism unit according to 1. 11. The liquid crystal mounting plate fixing portion includes a locking portion provided outside each side surface of the upper frame and the lower frame, and the engaging portions provided at corresponding positions of the liquid crystal mounting plate. The prism unit according to claim 1, further comprising an engagement portion that engages with a stop portion to fix the liquid crystal mounting plate. 12. The locking portion comprises projections provided on the outer sides of the upper frame and the lower frame, and the engaging portions are located at respective positions corresponding to the locking portions of the liquid crystal mounting plate. 12. The prism unit according to claim 11, wherein the projection is formed as an insertion hole through which the projection is inserted. 13. The prism unit according to claim 12, wherein the insertion hole is a protruding hole. 14. The prism unit according to claim 12, wherein the projection and the insertion hole are adhesively fixed in a predetermined state in which the projection is inserted through the insertion hole. 15. The projection according to claim 12, wherein the projections extend outward from respective side surfaces of the upper frame and the lower frame, and are integrally formed on the upper frame and the lower frame. The prism unit according to 1. 16. The prism according to claim 12, wherein the engaging portion is provided on the liquid crystal mounting plate, and the engaging portion is provided on a side surface of the upper frame and the lower frame. unit. 17. The prism unit according to claim 1, wherein the polarization filter section is made of a glass plate on which the polarization filter is mounted. 18. The lower frame 7 includes a stopper for supporting a lower portion of the glass plate, and a guide groove for preventing the lower portion of the glass plate from shifting or tilting in the front-rear direction. 18. The prism unit according to 17. 19. The prism unit according to claim 1, wherein the polarization filter section includes a glass plate on which the polarization filter is mounted, and a polarization mounting plate for mounting the glass plate. 20. The prism unit according to claim 19, wherein the polarization mounting plate is formed of an aluminum member. 21. The prism unit according to claim 19, wherein the polarization attachment plate has a finger hook for inserting and removing the polarization attachment plate by hand at an upper portion thereof. 22. The polarization mounting plate, wherein each of the left and right lower portions has a downwardly projecting projection, and the polarization mounting plate is inserted through a position of the lower frame corresponding to the projection. 22. The prism unit according to claim 19, further comprising a guide hole for preventing a deviation and a tilt in a front-rear direction of the prism unit. 23. The opening of the upper frame is provided with cutout holes at both ends in the longitudinal direction for preventing the glass plate or the polarizing plate from shifting or tilting in the front-rear direction. 23. The prism unit according to any one of items 17 to 22. 24. The prism unit according to claim 17, wherein the upper frame includes a pressing plate for preventing the glass plate or the polarization mounting plate from dropping upward. 25. The pressing plate integrally forms a locking piece projecting left and right outside, and engages with the locking piece at a position corresponding to the locking piece on a side surface of the upper frame. The prism unit according to claim 24, further comprising an engagement hole for holding the holding plate. 26. The prism unit according to claim 24, wherein the pressing plate is formed by a spring member. 27. The pedestal according to claim 1, wherein the pedestal is provided with a screw insertion hole for inserting a fixing screw for screwing the pedestal into a predetermined position of the liquid crystal projector to fix the pedestal. The described prism unit. 28. The pedestal according to claim 1, wherein the pedestal is provided with a positioning hole for inserting a positioning jig or a guide pin for positioning the pedestal at a predetermined position of the liquid crystal projector. The described prism unit. 29. The pedestal is provided with the screw insertion hole at a portion extending outward on the radiation side of the prism, and the screw insertion hole is formed so that a fixing screw can be inserted from above, The upper frame and the lower frame each have a cutout portion that allows the fixing screw to be inserted into the screw insertion hole from above with a tool such as a screwdriver so that the fixing screw can be screwed into the upper frame and the lower frame. The described prism unit.