Abstract:
A projection panel assembly is mounted on a casing for holding a screen so as to mount a front panel on the viewing side of the screen. The projection panel assembly includes a fixing portion for directly fixing the front panel and a supporting portion for movably supporting the front panel via the fixing portion. This makes it possible to absorb any distortion of the front panel due to thermal expansion and contraction.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a projection panel assembly used for, for example, a front panel placed on the front side of a projection apparatus, to a projection apparatus having the projection panel assembly, and to a production method of the projection apparatus. 
     2. Description of the Related Art 
     Projection apparatuses are known in which an image or the like is projected onto a relatively large screen from its rear side. 
     FIGS. 8 and 9 are a front view and a sectional view, respectively, of such a projection apparatus  100 . 
     Referring to FIG. 9, the projection apparatus  100  includes an optical unit  140  for projecting an image or the like onto a screen  120 , and a reflection plate  150  for reflecting the image or the like projected from the optical unit  140  toward a front panel  130 . The image or the like reflected from the reflection plate  150  is projected onto the screen  120 , and an user views the image via the front panel  130 . 
     The screen  120  and the front panel  130  are held by a bezel body  160  serving as a casing shown in FIG.  8 . 
     FIG. 10 is an end view showing the relationship between the screen  120  and the front panel  130  disposed on the front side thereof. Referring to FIG. 10, the screen  120  is composed of, for example, two members, and is fixed to the bezel body  160  by a fixture  2 . 
     The front panel  130  is placed on the front side of the screen  120  with a fixed space therebetween. The front panel  130  serves to improve the contrast when illuminated by external light and to protect the screen  120 , and is fixed to the bezel body  160  with an adhesive tape  5 . 
     The front panel  130  and the bezel body  160  expand or contract due to the heat generated by the projection apparatus  100 , changes in outside air temperature, or changes in humidity. The coefficients of expansion or contraction differ between the front panel  130  and the bezel body  160 . 
     For this reason, the front panel  130  may be distorted or the adhesive tape  5  may be separated due to the difference in coefficient of expansion or contraction. This results in defects of the projection apparatus  100  itself. 
     SUMMARY OF THE INVENTION 
     In view of the above problems, an object of the present invention is to provide a projection panel assembly in which the distortion or the like of a front panel due to expansion or contraction can be absorbed, a projection apparatus having the projection panel assembly, and a production method of the projection apparatus. 
     In order to achieve the above object, according to an aspect of the present invention, there is provided a projection panel assembly mounted on a casing for holding a screen so as to mount a front panel on the front side of the screen, the projection panel assembly including a fixing portion for directly fixing the front panel, and a supporting portion for movably supporting the front panel via the fixing portion. 
     Since the projection panel assembly includes the fixing portion for directly fixing the front panel and the supporting portion for movably supporting the front panel via the fixing portion, even when the front panel or the casing deforms due to expansion or contraction, the deformation can be absorbed by the movement of the fixing portion in connection with the supporting portion. 
     Preferably, the supporting portion is fixed to the casing. 
     Since the supporting portion is fixed to the casing, the fixing portion and the front panel supported by the supporting portion are fixed to the casing via the supporting portion. 
     Preferably, the supporting portion is disposed so as to fix the screen to the casing. 
     Since the screen is fixed to the casing by the supporting portion, the fixing portion and the screen can be fixed to the casing by the single supporting portion. 
     According to another aspect of the present invention, there is provided a projection apparatus having a projection panel assembly mounted on a casing for holding a screen so as to mount a front panel on the front side of the screen, wherein the projection panel assembly includes a fixing portion for directly fixing the front panel, and a supporting portion for movably supporting the front panel via the fixing portion. 
     Since the projection apparatus includes the fixing portion for directly fixing the front panel and the supporting portion for movably supporting the front panel via the fixing portion, even when the front panel or the casing deforms due to expansion or contraction, the deformation can be absorbed by the movement of the fixing portion in connection with the supporting portion. 
     Preferably, the front panel has, on the inner light-source side thereof, a contact portion with which the fixing portion of the projection panel assembly is contacted, and a front panel center portion adjacent to the contact portion. The contact portion has no antireflective portion. 
     In this case, when the fixing portion of the projection panel assembly is fixed to the front panel, a sufficient adhesion can be ensured between the contact portion of the front panel and the fixing portion, and the fixing portion can be fixed firmly. This avoids problems, such as a weak fixing force, and improves the reliability of the projection apparatus. Furthermore, by forming the antireflective portion in the front panel center portion, the contrast of an image or the like on the screen is improved. 
     Preferably, a printed shading portion is formed so as to include at least the contact portion of the front panel. 
     In this case, the fixing state of the contact portion of the front panel to the fixing portion is prevented by the printed shading portion from being viewed from the outside. Therefore, the outward appearance is good, and this does not cause the user of the projection apparatus to feel unpleasant. 
     Preferably, an antireflective portion is formed on the entire viewing-side surface of the front panel. 
     Since the antireflective portion is formed on the entire viewing-side surface of the front panel, antireflective portions are formed on both the viewing-side and the light-source-side surfaces of the front panel center portion. This improves the contrast when illuminated by external light, compared with a case in which an antireflective portion is formed only on the light-source-side or viewing-side surface. 
     Preferably, the antireflective portion is formed of a film coated with an AR solvent. 
     In this case, in particular, the antireflective film can be precisely and easily formed on the portions of the front panel other than the contact portion. 
     According to a further aspect of the present invention, there is provided a production method of a projection apparatus having a projection panel assembly mounted on a casing for holding a screen so as to mount a front panel on the outer viewing side of the screen, the production method including the steps of forming a projection panel assembly having a fixing portion for fixing the front panel, and a supporting portion for movably supporting the front panel via the fixing portion, forming a contact portion for contacting the fixing portion therewith on the inner light-source side of the front panel, forming a printed shading portion including at least the contact portion, forming an antireflective portion on the light-source side surface of the front panel except for the contact portion, and fixing the fixing portion to the contact portion so as to mount the front panel in the projection panel assembly. 
     In this case, since the supporting portion is fixed to the casing, the fixing portion and the front panel supported by the supporting portion are fixed to the casing via the supporting portion. The antireflective portion is formed on the front panel except for the contact portion. Therefore, the fixing portion of the projection panel assembly can be firmly fixed to the front panel because a sufficient adhesion is ensured between the contact portion of the front panel and the fixing portion. This does not cause problems, such as a weak fixing force, and improves the reliability of the projection apparatus. By forming the antireflective portion, the contrast of an image or the like on the screen when illuminated by external light can be improved. 
     Preferably, the production method further includes the step of forming an antireflective portion on the entire viewing-side surface of the front panel. 
     Preferably, the antireflective portion is formed of a film coated with an AR solvent. 
     Further objects, features, and advantages of the present invention will become apparent from the following description of the preferred embodiments with reference to the attached drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic sectional view showing the relationship among a bezel body, a screen, a front panel, and the like. 
     FIG. 2 is a view of holes formed in the bezel body. 
     FIG. 3 is a view of a front panel mounting member. 
     FIG. 4 is a view showing a state in which the front panel mounting members are fixed on the front panel. 
     FIG. 5 is a view showing a state in which screen engaging end portions of screen fixtures are inserted in screen fixture engaging holes. 
     FIG. 6 is a schematic sectional view showing the principal part of a projection apparatus according to a second embodiment of the present invention. 
     FIG. 7 is a sectional view of a front panel shown in FIG.  6 . 
     FIG. 8 is a front view of a projection apparatus. 
     FIG. 9 is a schematic sectional view of the projection apparatus shown in FIG.  8 . 
     FIG. 10 is a schematic end view showing the relationship between a screen and a front panel in a conventional projection apparatus. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 is a schematic end view showing the relationship among a bezel body  160 , a screen  120 , a front panel  130 , and the like in a projection apparatus  100  according to a first embodiment of the present invention. 
     The bezel body  160  is L-shaped in cross section, and has holes  161 . 
     The holes  161  are substantially rectangular through holes, as shown in FIG.  2 . Six holes  161  are formed on each of the short sides of the bezel body  160 , and nine holes  161  are formed on each of the long sides thereof. 
     In FIG. 1, two projections  162  are formed at the bottom end of the bezel body  160  so as to contact the screen  120 . On the side of the bezel body  160  opposite from the projections  162  in contact with the screen  120 , a positioning member  163  for positioning the front panel  130  is formed so as to contact with the front panel  130 . 
     The screen  120  in contact with the projections  162  of the bezel body  160  is, more specifically, composed of two screens, a Fresnel screen  120   a  and a lenticular screen  120   b.    
     In FIG. 1, the Fresnel screen  120   a  is made of, for example, acrylic, polycarbonate, or a compound of both, and serves to collimate light beams projected from an optical unit  140 . 
     The lenticular screen  120   b  is similarly made of, for example, acrylic, polycarbonate, or a compound of both, and serves to spread out the projected light beams collimated by the Fresnel screen  120   a  in the right and left direction. 
     The front panel  130  is placed on the outer side (left side in FIG. 1) of the screen  120  having such a structure with the bezel body  160  therebetween is called a “contrast screen”, and serves to improve the contrast when illuminated by external light and to protect the viewing-side surface of the screen  120 . 
     The front panel  130  is also made of, for example, acrylic, polycarbonate, or a compound of both. 
     The front panel  130  is fixed onto front panel mounting members  170  serving as the fixing portion with an adhesive tape  180  or an adhesive. The front panel mounting members  170  are shaped as shown in FIGS. 1 and 3. FIG. 3 shows only the front panel mounting member  170  shown in FIG. 1, as viewed from above. 
     Each of the front panel mounting members  170  has an adhesive tape mounting surface  171 . The front panel  130  is fixed on the front panel mounting members  170  with the adhesive tapes  180  placed on the adhesive tape mounting surfaces  171 . 
     FIG. 4 is a general view of the front panel  130  to which the front panel mounting members  170  are fixed with the adhesive tapes  180 . 
     The front panel mounting members  170  have screen fixture engaging holes  172  to be engaged with engaging end portions  191  of screen fixtures  190  serving as the supporting portion, which will be described later. 
     As shown in FIG. 3, the screen fixture engaging holes  172  are substantially rectangular through holes, and are slightly larger than the engaging end portions  191  of the screen fixtures  190 . For this reason, even when the engaging end portions  191  of the screen fixtures  190  are inserted in and engaged with the screen fixture engaging holes  172 , they are not fixed firmly, but are fitted therein with some play. 
     Each of the screen fixtures  190  to be engaged with the screen fixture engaging holes  172  is fixed to the bezel body  160  by fixing screw  200 , as shown in FIG.  1 . The screen fixture  190  is engaged with the front panel mounting member  170  at the engaging end portion  191  disposed at the upper end thereof. A screen fixing portion  192  is formed at the lower end thereof so as to fixedly press the surface of the Fresnel screen  120   a  of the screen  120 . 
     In this way, in the projection apparatus  100  of this embodiment, the front panel mounting members  170  are engaged with the screen fixtures  190 , and the front panel  130  is fixed on the front panel mounting members  170  with the adhesive tapes  180 . The screen  120  is also fixed by the screen fixtures  190 . These components constitute a projection panel assembly. 
     The projection panel assembly and the projection apparatus  100  including the projection panel assembly of this embodiment described above operate as follows. 
     The optical unit  140  and the like are placed in the projection apparatus  100 , the screen  120  is mounted on the bezel body  160 , as shown in FIG. 1, and the screen fixtures  190  are fixed by the fixing screws  200  so that they clamp the screen  120 . 
     On the other hand, the front panel mounting members  170  are bonded onto the front panel  130  with the adhesive tapes  180 , as shown in FIG.  4 . The portions at the screen fixture engaging holes  172  of the front panel mounting members  170  are inserted inward through the holes  161  of the bezel body  160 . 
     The screen fixture engaging end portions  191  of the screen fixtures  190  are inserted in and engaged with the inserted screen fixture engaging holes  172 , as shown in FIG.  5 . Even when the screen engaging end portions  191  of the screen fixtures  190  are inserted in the screen fixture engaging holes  172 , they are movable because a clearance A is formed therebetween. 
     In this way, the front panel  130  of this embodiment is not directly bonded to the bezel body  160 , but is indirectly mounted on the bezel body  160  with the front panel mounting members  170  and the screen fixtures  190  therebetween. The front panel mounting members  170  attached to the front panel  130  are movable with respect to the holes  161  of the bezel body  160  and the engaging end portions  191  of the screen fixtures  190 . 
     Therefore, even if the front panel  130  principally made of acrylic, polycarbonate, or a compound of both, and the bezel body  160  made of, for example, a polystyrene compound expand or contract at different coefficients due to heat generated by the projection apparatus  100 , or changes in outside air temperature or humidity because there is a difference between their materials, the difference in coefficient of expansion or contraction is absorbed by the movable portions. 
     That is, since the front panel mounting members  170  are movable with respect to the holes  161  of the bezel body  160  and the engaging end portions  191  of the screen fixtures  190 , the front panel  130  is prevented by the movement of the front panel mounting members  170  from being distorted and from separating from the bezel body  160 . 
     According to such a projection apparatus  100  of this embodiment, distortion and the like of the front panel  130  and the bezel body  160  due to changes in temperature and humidity are absorbed by the front panel mounting members  170 , the screen fixtures  190 , and the like, thereby reducing stress to be applied to the bonding surfaces between the front panel mounting members  170  and the front panel  130  and reducing surface strain of the front panel  130 . Since the screen fixtures  190  fix both the screen  120  and the front panel mounting members  170 , it is possible to reduce the number of components and to thereby reduce the cost. 
     While both the screen  120  and the front panel mounting members  170  are fixed by the screen fixtures  190  in this embodiment, they may be fixed by separate fixing members. 
     FIG. 6 is a schematic sectional view showing the principal part of a projection apparatus  210  according to a second embodiment of the present invention. Since the configuration of the projection apparatus  210  of this embodiment is substantially similar to that of the projection apparatus  100  of the above-described first embodiment, the differences from the projection apparatus  100  are described below. The components common to those in the first embodiment are denoted by the same numerals, and descriptions thereof are omitted. 
     Since the projection apparatus  210  of this embodiment is different from the projection apparatus  100  of the first embodiment principally in the structure of a front panel  230 , the following description will be given with particular emphasis on the structure of the front panel  230 . 
     FIG. 6 shows a state in which the front panel  230  is mounted on a bezel body  160  of the projection apparatus  210 , and FIG. 7 shows a state in which front panel mounting members  170  are bonded to the front panel  230  with adhesive tapes  180 . 
     The structure of the front panel  230  will be more specifically described with reference to FIGS. 6 and 7. First, the front panel  230  has a front panel base  235  at its center. The front panel base  235  is made of, for example, acrylic or polycarbonate, in a manner similar to that of the front panel  130  of the first embodiment. 
     As shown in FIG. 4, printed edge portions  232  serving as printed shading portions are formed on the light-source side of the front panel base  234  on the inner side of the projection apparatus  210 . More specifically, the printed edge portions  232  are formed at fixed intervals around the entire periphery of the front panel base  235 . 
     In the printed edge portions  232  thus formed, adhesive portions  231  serving as the contact portions are formed. In FIG. 6, the adhesive portions  231  are formed corresponding to the front panel mounting members  170 . In FIG. 6, the adhesive portions  231  are formed on the surfaces of the printed edge portions  232 , and the adhesive tapes  180  are bonded thereto. 
     The adhesive tapes  180  are placed on the adhesive portions  231 , as shown in FIG. 6, and the front panel mounting members  170  are bonded to the front panel  230 . 
     That is, the front panel mounting members  170  are placed corresponding to the printed edge portions  232 , as shown in FIG.  6 . Therefore, the printed edge portions  232  serve to prevent the front panel mounting members  170  from being seen from the outside of the front panel  230 . 
     An AR (antireflection) film  233  is bonded on the entire surface of the front panel base  235  except on the printed edge portions  232 , as shown in FIG.  7 . 
     Therefore, the AR film  233  completely covers a transparent portion  234  (an area enclosed by a two-dot chain line shown in FIG. 4) of the front panel  230 . Images are projected onto the transparent portion  234 . 
     By placing the AR film  233  on the front panel  230 , the contrast of an image projected onto the surface of the front panel  230  is prevented from being decreased when illuminated by external light. 
     An AR film  233  is also placed on the outer side of the front panel base  235 , as shown in FIG. 6, so as to cover the entire outer surface of the front panel base  235 . 
     By thus placing the AR films  233  on both sides of the front panel base  235 , the contrast of an image projected onto the surface of the front panel  230  can be prevented from being decreased when illuminated when illuminated by external light, and this allows the user to more easily view the image. 
     A description will be given below of a method for producing the front panel  230  with the above structure. 
     First, printed edge portions  232  shown in FIG. 7 are printed on the inner surface (light-source side) of the front panel base  235  shown in FIG.  6 . 
     After that, an AR film  233  having the same size as that of the front panel base  235  is bonded onto the entire outer surface of the front panel base  235 . 
     Next, an AR film  233  is bonded onto the inner surface of the front panel base  235 , as shown in FIG.  7 . 
     When the AR film  233  is thus bonded onto the inner surface of the front panel base  235 , it is not placed in the printed edge portions  232  on the periphery of the front panel center portion, but is placed only in the front panel center portion. 
     Since the printed edge portions  232  have the adhesive portions  231  to which the front panel mounting members  170  are to be bonded, as described above, the AR film  233  is not placed on the adhesive portions  231 . 
     Conventionally, the front panel is subjected to antireflection coating, for example, in the following procedure in order to prevent the contrast of an image projected onto the surface of the front panel from being decreased when illuminated by external light. 
     That is, an abrasion-resistant hard-coating solvent is applied onto the entire front and rear surfaces of a screen original formed by extrusion molding, and is soaked in an AR solvent, thereby subjecting the front panel to AR coating. 
     Then, the above-described edge printing is performed on the AR-coated front panel. Adhesive tapes or the like are placed on the adhesive portions of the printed edge portions, and the front panel is bonded to the main body of the projection apparatus. 
     Therefore, the area of the front panel on which the adhesive tapes are to be placed is subjected to both AR coating and edge printing. When printing is thus performed on the AR-coated portion, since the adhesion of ink is seriously reduced, the bonding force in the printed portion is insufficient, and fixing to the front panel is unstable. Even when the front panel is first subjected to the above edge printing, and is then subjected to AR coating, since the adhesion of adhesive tapes onto the AR-coated portion is seriously reduced, and this also makes fixing to the front panel unstable. 
     In this embodiment, however, the printed edge portions  232  are first formed on the front panel  230 , and no AR film  233  is form in the area where the adhesive tapes are placed, the adhesion of printing ink will not be decreased, and the bonding force of the adhesive tapes will also not be reduced. For this reason, the front panel  230  and the front panel mounting members  170  can be bonded with a sufficient bonding force. 
     This vastly improves the reliability of the projection apparatus  210 . 
     The inner-side portion of the front panel base  235  of the front panel  230  where no AR film  233  is formed does not have any influence on the projected images. For this reason, a decrease in contrast of images when illuminated by external light due to the absence of the AR film  233  can be avoided. Furthermore, since printing is not performed on the viewing side, but on the light-source side, a good external appearance can be maintained. 
     The front panel  230  thus produced is bonded to the front panel mounting members  170  with the adhesive tapes  180 , and is fixed to the bezel body  160  of the projection apparatus  210 . 
     The projection apparatus  210  is completed through further predetermined production processes. 
     While the present invention has been described with reference to what are presently considered to be the preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. On the contrary, the invention is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.