Abstract:
A display holding device of projection television is secured on a cabinet of the projection television and has a rigid material section secured on the cabinet, and an elastic material section for sandwiching the display section, which is integrally formed on the rigid material section. The display section has a screen on which an image is projected and a filter which is provided outside the screen to face the screen at a certain distance. The elastic material section has first to fourth protuberances. The screen is sandwiched between the first and second protuberances on the elastic material section. The filter is sandwiched between the third and fourth protuberances on the elastic material section.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a display holding device of a projection television, which secures a screen and a filter on a cabinet of a rear-projection-type projection television (hereinafter referred to as PTV). 
     FIG. 19 is a sectional view schematically showing a conventional PTV display holding device. As shown in FIG. 19, the display holding device has a screen frame 22 secured on a cabinet 1, a screen mount 23 fastened on the screen frame 22 by screws 4, and a filter mount 25 fit on the screen frame 22. Protection tape 26-29 is utilized to prevent a screen 6 and a filter 7 from being damaged due to impact, vibration, and other causes. The screen 6 is tightly sandwiched between the protection tape 26 on the screen mount 23 and the protection tape 27 on the screen frame 22, and the filter 7 is tightly sandwiched between the protection tape 28 on the screen frame 22 and the protection tape 29 on the filter mount 25. 
     Manufacturing the conventional display holding device described above requires that the protection tape 26, 27, 28 and 29 be placed consistently near the outer edges of the screen frame 22, the screen mount 23 and the filter mount 25. The troublesome work increases the manufacturing cost of the conventional PTV. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a display holding device of a projection display (PTV display holding device) which can effectively protect a filter and a screen from damage due to impact or vibration and which can be manufactured at a lower cost. 
     According to the present invention, a display holding device of projection television is secured on a cabinet of the projection television and has a rigid material section secured on the cabinet; and an elastic material section for sandwiching the display section, which is integrally formed on the rigid material section. The display section has a screen on which an image is projected and a filter which is provided outside the screen to face the screen at a certain distance. The elastic material section has first to fourth protuberances. The screen is sandwiched between the first and second protuberances on the elastic material section. The filter is sandwiched between the third and fourth protuberances on the elastic material section. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein: 
     FIG. 1 is a cross section showing the configuration of the PTV display holding device in a first embodiment of the present invention; 
     FIG. 2 is an exploded perspective view showing a screen holder, a screen mount and a filter mount of the PTV display holding device shown in FIG. 1; 
     FIG. 3 is a perspective view schematically showing the outward appearance of a PTV incorporating the PTV display holding device shown in FIG. 1; 
     FIG. 4 is a cross section showing the configuration of the PTV display holding device in a second embodiment of the present invention; 
     FIG. 5 is a cross section showing the configuration of the PTV display holding device in a third embodiment of the present invention; 
     FIG. 6 is a cross section showing the configuration of the PTV display holding device in a fourth embodiment of the present invention; 
     FIG. 7 is a cross section showing the configuration of the PTV display holding device in a fifth embodiment of the present invention; 
     FIG. 8 is a cross section showing the configuration of the PTV display holding device in a sixth embodiment of the present invention; 
     FIG. 9 is an exploded perspective view showing a screen holder, a screen mount and a filter mount of the PTV display holding device shown in FIG. 8; 
     FIG. 10 is a cross section showing the configuration of the PTV display holding device in a seventh embodiment of the present invention; 
     FIG. 11 is an exploded perspective view showing the screen holder, the screen mount and the filter mount of the PTV display holding device shown in FIG. 10; 
     FIG. 12 is a cross section showing the configuration of the PTV display holding device in an eighth embodiment of the present invention; 
     FIG. 13 is a perspective view showing the plate holder of the PTV display holding device shown in FIG. 12; 
     FIG. 14 is a cross section showing the configuration of the PTV display holding device in a ninth embodiment of the present invention; 
     FIG. 15 is a perspective view showing a plate holder of the PTV display holding device shown in FIG. 14; 
     FIG. 16 is a cross section showing the configuration of the PTV display holding device in a tenth embodiment of the present invention; 
     FIG. 17 is a cross section showing the configuration of the PTV display holding device in an eleventh embodiment of the present invention; 
     FIG. 18 is a perspective view showing a plate holder of a the PTV display holding device shown in FIG. 17; and 
     FIG. 19 is a cross section showing the configuration of a conventional PTV display holding device. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Preferred embodiments of the present invention will be described with reference to attached drawings. 
     First Embodiment 
     FIG. 1 and FIG. 2 are a cross section and an exploded perspective view showing a PTV display holding device in the first embodiment of the present invention. FIG. 3 is a perspective view schematically showing the outward appearance of a PTV incorporating the display holding device shown in the first embodiment. FIG. 1 shows the cross-sectional view of the PTV taken along a line A--A of FIG. 3. 
     As shown in FIG. 1 or FIG. 2, the display holding device in the first embodiment has a screen frame 2 fastened on a PTV cabinet 1 by screws or the like , which are not shown in the figures, a screen mount 3 fastened on the screen frame 2 by screws 4 (multiple screws are used although Just a single screw is shown in FIG. 1), and a filter mount 5 which fits into a depression formed on the outer surface of the screen frame 2 at one end. The screen frame 2, the screen mount 3 and the filter mount 5 are made of a rigid material such as rigid vinyl chloride. 
     The screen mount 3 has a first protuberance 3a, which is integrally formed on the screen mount 3 but is made of an elastic or flexible material. In the first embodiment, the first protuberance 3a is shaped like a long strip disposed in parallel with the edge of the screen 6, which is about 3.0  mm! to 7.0  mm! thick, or disposed perpendicular to the plane containing FIG. 1 (see FIG. 2). The screen frame 2 has second and third protuberances 2a and 2b, which are integrally formed on the screen frame 2 but are made of an elastic material. The second protuberance 2a is shaped like a long strip disposed in parallel with the edge of the screen 6, as shown in FIG. 2. The third protuberance 2b is shaped like a long semicircular cylinder of which longitudinal axis is parallel with the edge of the filter 7, which is about 3.0  mm! thick. The filter mount 5 has a fourth protuberance 5a, which is integrally formed on the filter mount 5 but is made of an elastic material. The fourth protuberance 5a is shaped like a long semicircular cylinder of which longitudinal axis is parallel with the edge of the filter 7, as shown in FIG. 2. The screen 6 includes a Fresnel lens 6a laid over a lenticular screen 6b. 
     The first protuberance 3a is made of soft vinyl chloride, for instance, and is simultaneously formed with the screen mount 3 through dual molding. The second and third protuberances 2a and 2b are made of soft vinyl chloride, for instance, and are simultaneously formed with the screen frame 2 through dual molding. The fourth protuberance 5a is made of soft vinyl chloride, for instance, and is simultaneously formed with the filter mount 5 through dual molding. The dual molding is achieved, for example, by extruding or injection-molding a composite material including layers of rigid vinyl chloride and soft vinyl chloride. 
     FIG. 1 illustrates just the top side of the screen 6 and the filter 7. The screen 6 and the filter 7, however, are tightly sandwiched between the first to fourth protuberances at the bottom side, left side, and right side in the same way. The screen 6 and the filter 7 may be sandwiched between the first to fourth protuberances just at a part near the edges. However, it is preferable to sandwich the screen 6 and the filter 7 between the first to fourth protuberances consistently near the edges. 
     As has been described above, the display holding device in the first embodiment eliminates the need for the troublesome manufacturing step of adhering protection tape on the screen frame and the like. The manufacturing process is simplified, and the number of necessary components is reduced. Accordingly, the product price can be lowered. 
     The display holding device in the first embodiment can also hold the screen 6 and filter 7 securely and protect them from damage. 
     Since the first to fourth protuberances 3a, 2a, 2b and 5a are made of soft vinyl chloride, the effect of the impact and vibration on the filter and screen during transportation is reduced. This prevents the Fresnel lens 6a and lenticular screen 6b from rubbing against each other, consequently preventing a white powdery substance from being produced. 
     Second Embodiment 
     FIG. 4 is a cross section schematically showing the display holding device in the second embodiment of the present invention. In FIG. 4, members identical to or corresponding to those shown in FIG. 1 are denoted by the same reference numerals. As shown in FIG. 4, the display holding device in the second embodiment is different from the display holding device in the first embodiment described earlier in that the first and second protuberances 3a and 2a are not shaped like long strips but shaped like long semicircular cylinders of which longitudinal axes are parallel with the edge of the screen 6. The display holding device in the second embodiment has the same effect as the display holding device in the first embodiment described earlier. Except for the difference mentioned above, the display holding device in the second embodiment is the same as the display holding device in the first embodiment described earlier. 
     Third Embodiment 
     FIG. 5 is a cross section schematically showing the display holding device in the third embodiment of the present invention. In FIG. 5, members identical to or corresponding to those shown in FIG. 1 are denoted by the same reference numerals. As shown in FIG. 5, the display holding device in the third embodiment is different from the display holding device in the first embodiment described earlier in the following points. The first and second protuberances 3a and 2a are not shaped like strips but shaped like long semicircular cylinders of which longitudinal axes are parallel with the edge of the screen 6. The first protuberance 3a is in contact with the screen 6 at a position closer to the edge of the screen 6 (at a higher position in FIG. 5) than the second protuberance 2a. The display holding device in the third embodiment has the same effect as the display holding device in the first embodiment described earlier and can also hold the screen 6 so that the screen is slightly curved around its center towards the inside of the PTV. This brings the Fresnel lens 6a and lenticular screen 6b constituting the screen 6 into intimate contact with one another. Except for the differences mentioned above, the display holding device in the third embodiment is the same as the display holding device in the first embodiment described earlier. 
     Fourth Embodiment 
     FIG. 6 is a cross section schematically showing the display holding device in the fourth embodiment of the present invention. In FIG. 6, members identical to or corresponding to those shown in FIG. 1 are denoted by the same reference numerals. As shown in FIG. 6, the display holding device in the fourth embodiment is different from the display holding device in the first embodiment describe earlier in these points. The first and second protuberances 3a and 2a are not shaped like strips but shaped like long semicircular cylinders. The first protuberance 3a is in contact with the screen 6 at a position closer to the edge of the screen 6 (at a higher position in FIG. 6) than the second protuberance 2a. The third protuberance 2b is in contact with the filter 7 at a position closer to the edge of the filter 7 (at a higher position in FIG. 6) than the fourth protuberance 5a. The display holding device in the fourth embodiment has the same effect as the display holding device in the first embodiment described earlier and also holds the screen 6 and filter 7 so that they are slightly curved around their centers towards the inside of the PTV. Except for the differences mentioned above, the display holding device in the fourth embodiment is the same as the display holding device in the first embodiment described earlier. 
     Fifth Embodiment 
     FIG. 7 is a cross section schematically showing the display holding device in the fifth embodiment of the present invention. In FIG. 7, members identical to or corresponding to those shown in FIG. 1 are denoted by the same reference numerals. As shown in FIG. 7, the display holding device in the fifth embodiment is different from the display holding device in the first embodiment described earlier just in the following points. The first and second protuberance 3a and 2a are not shaped like strips but shaped like long semicircular cylinders. The first protuberance 3a is in contact with the screen 6 at a position closer to the edge of the screen 6 (at a higher position in FIG. 7) than the second protuberance 2a. The fourth protuberance 5a is in contact with the filter 7 at a position closer to the edge of the filter 7 (at a higher position in FIG. 7) than the third protuberance 2b. The display holding device in the fifth embodiment has the same effect as the display holding device in the first embodiment described earlier, and holds the screen 6 and filter 7 so that the screen 6 is slightly curved around its center towards the inside of the PTV and that the filter, is slightly curved around its center towards the outside of the PTV. This prevents the screen 6 and filter 7 from rubbing against each other, consequently preventing a white powdery substance from being produced. Except for the differences mentioned above, the display holding device in the fifth embodiment is the same as the display holding device in the first embodiment described earlier. 
     Sixth Embodiment 
     FIGS. 8 and 9 are a cross section and an exploded perspective view showing the display holding device in the sixth embodiment of the present invention. In FIGS. 8 and 9, members identical to or corresponding to those shown in FIG. 1 are denoted by the same reference numerals. As shown in FIG. 8 or 9, the display holding device in the sixth embodiment is different from the display holding device shown in FIG. 1 in the following points. The first to fourth protuberances 3a, 2a, 2b and 5a are shaped like long hollow semicircular cylinders of which longitudinal axes are parallel with the edge of the screen 6 or filter 7. The first to fourth protuberances 3a, 2a, 2b and 5a are integrally formed on the screen frame 2, screen mount 3, or filter mount 5 in such a manner that the screen frame 2, screen mount 3, or filter mount 5 is joined with the individual protuberances at their two sides parallel to the longitudinal axes. Since the elastic material section is shaped like a hollow semicircular cylinder (with a ring-formed cross section), the display holding device in the sixth embodiment has high elasticity and can securely hold the filter 7 and screen 6 even if the thicknesses of the filter 7 or screen 6 varies. Except for the differences mentioned above, the display holding device in the sixth embodiment is the same as the display holding device in the first embodiment described earlier. As shown in FIGS. 5 to 7, the contact position of the first protuberance 3a may be displaced from the contact position of the second protuberance 2a, and the contact position of the third protuberance 2b may be displaced from the contact position of the fourth protuberance 5a. 
     Seventh Embodiment 
     FIGS. 10 and 11 are a cross section and an exploded perspective view schematically showing the display holding device in the seventh embodiment of the present invention. In FIGS. 10 and 11, members identical to or corresponding to those shown in FIG. 1 are denoted by the same reference numerals. As shown in FIG. 10 or 11, the display holding device in the seventh embodiment is different from the display holding device shown in FIG. 1 in the following points. The first to fourth protuberances 3a, 2a, 2b and 5a are shaped like long hollow semicircular cylinders (with a U-shaped cross section) of which longitudinal axes are parallel with the edge of the screen 6 or filter 7. The first to fourth protuberances 3a, 2a, 2b and 5a are integrally formed on the screen frame 2, screen mount 3, or filter mount 5 in such a manner that the screen frame 2, screen mount 3, or filter mount 5 is joined with the individual protuberances at either of their two sides parallel to the longitudinal axes. Since the elastic material section is shaped like a hollow semicircular cylinder, the display holding device in the seventh embodiment has high elasticity and can securely hold the filter 7 and screen 6 even if the thickness of the filter 7 or screen 6 varies. Except for the differences mentioned above, the display holding device in the seventh embodiment is the same as the display holding device in the first embodiment described earlier. As shown in FIGS. 5 to 7, the contact position of the first protuberance 3a may be displaced from the contact position of the second protuberance 2a, and the contact position of the third protuberance 2b may be displaced from the contact position of the fourth protuberance 5a. 
     Eighth Embodiment 
     FIG. 12 is a cross section schematically showing the display holding device in the eighth embodiment of the present invention. FIG. 13 is a perspective view showing a plate holder having first to fourth protuberances. 
     As shown in FIG. 12, the display holding device in the eighth embodiment includes a screen frame 12 secured on the PTV cabinet 1, a plate mount 13 fastened on the cabinet 1 by screws or the like, which are not shown in the figure, and a plate holder 14 fit into depressions 13a and 13b formed on the plate mount 13. The main body of the plate holder 14 is made of a rigid material such as rigid vinyl chloride. 
     The plate holder 14 has first to fourth protuberances 14a, 14b, 14c and 14d which are integrally formed on the main body of the plate holder 14 but are made of an elastic or flexible material. In the eighth embodiment, the first to fourth protuberances 14a, 14b, 14c and 14d are shaped like long semicircular cylinders disposed in parallel with the edge of the screen 6, or disposed perpendicular to the plane containing FIG. 1. The first to fourth protuberances 14a, 14b, 14c and 14d are made of soft vinyl chloride, for instance, and are integrally formed on the plate holder 14 through dual molding. 
     FIGS. 12 and 13 illustrate Just the top side of the screen 6 and filter 7. The screen 6 and filter 7, however, are tightly sandwiched between the first to fourth protuberances 14a, 14b, 14c and 14d at the bottom side, left side, and right side in the same way. 
     As has been described above, the display holding device in the eighth embodiment eliminates the need for the manufacturing step of adhering protection tape, enabling the manufacturing cost to be reduced. 
     The display holding device in the eighth embodiment can also hold the screen 6 and filter 7 securely and protect them from damage. 
     Since the first to fourth protuberances 14a, 14b, 14c and 14d are made of soft vinyl chloride, the effect of impact and vibration on the filter and screen during transportation is reduced. This prevents the Fresnel lens 6a and lenticular screen 6b from rubbing against each other, consequently preventing a white powdery substance from being produced. 
     Since just the plate holder 14 is a separate part, the manufacturing process is much simpler than the manufacturing process in the first embodiment, which uses three separate parts. 
     Except for the differences mentioned above, the display holding device in the eighth embodiment is the same as the display holding device in the first embodiment described earlier. 
     Ninth Embodiment 
     FIG. 14 is a cross section schematically showing the display holding device in the ninth embodiment of the present invention. FIG. 15 is a perspective view showing a plate holder having first to fourth protuberances. In FIGS. 14 and 15, members identical to or corresponding to those shown in FIGS. 12 and 13 are denoted by the same reference numerals. As shown in FIG. 14 or 15, the display holding device in the ninth embodiment is different from the display holding device in the eighth embodiment described earlier in the following points. The first protuberance 14a is in contact with the screen 6 at a position closer to the edge of the screen 6 (at a higher position in FIG. 14) than the second protuberance 14b. The third protuberance 14c is in contact with the filter 7 at a position closer to the edge of the filter 7 (at a higher position in FIG. 14) than the fourth protuberance 14d. The display holding device in the ninth embodiment has the same effect as the display holding device in the eighth embodiment described earlier and also holds the screen 6 and filter 7 so that they are slightly curved around their centers towards the inside of the PTV. Except for the differences mentioned above, the display holding device in the ninth embodiment is the same as the display holding device in the eighth embodiment described earlier. 
     Tenth Embodiment 
     FIG. 16 is a cross section schematically showing the display holding device in the tenth embodiment of the present invention. In FIG. 16, members identical to or corresponding to those shown in FIGS. 12 and 13 are denoted by the same reference numerals. As shown in FIG. 16, the display holding device in the tenth embodiment is different from the display holding device in the eighth embodiment described earlier in the following points. The first protuberance 14a is in contact with the screen 6 at a position closer to the edge of the screen 6 (at a higher the second pro in FIG. 16) than the second protuberance 14b. The fourth protuberance 14d is in contact with the filter 7 at a position closer to the edge of the filter 7 (at a higher position in FIG. 16) than the third protuberance 14c. The display holding device in the tenth embodiment has the same effect as the display holding device in the eighth embodiment described earlier and also holds the screen 6 and filter 7 so that the screen is slightly curved around its center towards the inside of the PTV and that the filter is slightly curved around its center towards the outside of the PTV. This prevents the screen 6 and filter 7 from rubbing against each other, consequently preventing a white powdery substance from being produced. Except for the differences mentioned above, the display holding device in the tenth embodiment is the same as the display holding device in the eighth embodiment described earlier. 
     Eleventh Embodiment 
     FIG. 17 is a cross section schematically showing the display holding device in the eleventh embodiment of the present invention. FIG. 18 is a perspective view showing a plate holder having first to fourth protuberances. In FIGS. 17 and 18, members identical to or corresponding to those shown in FIGS. 12 and 13 are denoted by the same reference numerals. As shown in FIG. 17 or 18, the display holding device in the eleventh embodiment is different from the display holding device in the eighth embodiment described earlier in the following point. The first to fourth protuberances 14a, 14b, 14c and 14d are shaped like hollow semicircular cylinders, as in FIG. 8. Since the elastic material section is shaped like a hollow semicircular cylinder, the display holding device in the eleventh embodiment has high elasticity and can securely hold the filter 7 and screen 6 even if the thicknesses of the filter 7 or screen 6 varies. As shown in FIGS. 14 to 16, the contact position of the first protuberance 14a may be displaced from the contact position of the second protuberance 14b, and the contact position of the third protuberance 14c may be displaced from the contact position of the fourth protuberance 14d. Except for the differences mentioned above, the display holding device in the eleventh embodiment is the same as the display holding device in the eighth embodiment described earlier.