Patent Publication Number: US-6908354-B1

Title: Method of producing flat panel displays

Description:
This application is a continuation of International Application No. PCT/JP00/01436, filed Mar. 9, 2000, designated the United States, which claims the benefit of Japanese Application No. 11-063859, filed Mar. 10, 1999, which is incorporated herein by reference in its entirety. 

   TECHNICAL FIELD 
   The present invention relates to a method for producing a flat type image forming apparatus (hereinafter referred to as a flat panel display). 
   BACKGROUND ART 
   The prior art will be described below by referring to  FIGS. 13 through 22 . 
     FIG. 22  is a sectional view of a flat panel display  200 . The flat panel display  200  is formed by a face plate  201 , a rear plate  202 , and a frame  203  connecting the face plate  201  to the rear plate  202 . Since the flat panel display is a vacuum inside, it includes an atmospheric-pressure-resistant support member  204  to withstand the atmospheric pressure. 
   The face plate  201  includes a face plate substrate glass  205 , a black stripe  206  which is a stopping member formed on the substrate glass  205 , an RGB fluorescent object  207 , and a metal back  208  for applying a voltage. The rear plate  202  includes a rear plate substrate glass  209 , an electronic source generation portion (not shown in  FIG. 22 ) formed on the substrate glass  209 , and a driving XY matrix wiring (not shown in FIG.  22 ). The atmospheric-pressure-resistant support member  204  is provided between the black stripe  206  of the face plate  201  and an upper wiring  210  of the driving XY matrix wiring of the rear plate  202 , and is fixed while maintaining predetermined conductivity by conductive adhesive members  211  and  212 . 
   Described below will be the procedure of assembling a flat panel display. 
     FIG. 13  is a sectional view of the face plate  201 . The face plate  201  is provided with an aperture  213  by removing a metal back of the portion to which the atmospheric-pressure-resistive support member is adhered using means such as a laser process, etc. to improve the adhesion as shown in FIG.  14 . 
   Then, a conductive adhesive  214  is applied to an aperture  213  (FIG.  15 ). 
   An assembly jig  216  having a positioning member  215  to which the atmospheric-pressure-resistant support member  204  is applied is used so that the atmospheric-pressure-resistant support member of the face plate  201  can be aligned on the position of the adhesion. The atmospheric-pressure-resistant support member  204  is fixed at a predetermined position of the face plate  201  with the conductive adhesive  214  (FIG.  16 ). 
   In this step, a face plate member  217  with the atmospheric-pressure-resistant support member  204  fixed at the predetermined position can be obtained (FIG.  17 ). 
   Then, a conductive frit, glass  218  and a frame adhering insulating frit glass  219  are applied on the upper wiring  210  of the driving XY matrix wiring on the rear plate substrate glass  209 , and are dried and provisionally sintered (FIGS.  18  and  19 ). 
   The face plate member  217  to which the atmospheric-pressure-resistant support member  204  is fixed at a predetermined position; the frame  203  to which the insulating frit glass  218  is applied on the face plate side, dried, and provisionally sintered; and the rear plate substrate glass  209  to which the conductive frit glass  218  and the frame adhering insulating frit glass  219  are applied on the upper wiring  210  of the driving XY matrix wiring, dried, and provisionally sintered are mounted at predetermined positions (FIGS.  20  and  21 ). All these members are heated by an electric furnace or a plate heater, and a frit glass is softened and pressed, thereby obtaining the flat panel display  200  (FIG.  22 ). 
   The present invention aims at realizing a method for producing a preferred flat panel display. 
   DISCLOSURE OF THE INVENTION 
   An aspect of the present invention relating to a method for producing a flat panel display is configured as follows. 
   That is, the method produces a flat panel display including a face plate portion and a rear plate portion opposite to each other, and a frame portion. The method is characterized in that it comprises a step of adhering a portion to be adhered between the face plate and the rear plate while guided by a jig. The jig functions as a guide such that the relative positions between the face plate and the rear plate are in a predetermined state at least in a direction within a plane of the plates, and the movement in the interval direction of the face plate and the rear plate can be allowed. 
   In this method, since the guide in a direction within a plane of the plates is provided by the jig, a flat panel display can be produced with high precision although there is a movement in the interval direction between the face plate and the rear plate. Furthermore, since the face plate and the rear plate can be aligned by the jig setting the positions, the face plate and the rear plate can be aligned although there is a movement in the interval direction between the face plate and the rear plate. 
   A flat panel display according to the present invention includes a substantially flat face plate portion and a substantially flat rear plate portion. The frame portion between the face plate portion and the rear plate portion can be adhered to the face plate and the rear plate in the step of adhering the frame member to the separately provided face plate and rear plate, or one of the face plate and the rear plate can be adhered to the frame member in advance before the adhering step, and the other is adhered to the frame member in the adhering step. Otherwise, when one of the face plate and the rear plate is produced, the frame portion may be simultaneously produced. 
   Another aspect of the present invention relating to a method for producing a flat panel display can be configured as follows. 
   That is, the method produces a flat panel display including a face plate portion and a rear plate portion opposite to each other, and a frame portion. The method has a step of aligning the relative positions between the face plate and the rear plate; a step of positioning a jig for determining relative positions in a direction within a plane of the plates between the face plate and the rear plate by fitting to the face plate and the rear plate in the aligned state; and a step of adhering a portion to be adhered between the face plate and the rear plate while setting the inside relative positions between the face plate and the rear plate using the jig. 
   According to each of the above mentioned inventions, it is preferable that the adhering step preferably contains a step of applying pressure to the portion to be adhered. 
   In addition, it is preferable that the adhering step includes a heating step. In the heating step, an adhesive of the portion to be adhered is rendered adhesive. Then, by pressing the portion to be adhered, by simply touching the portion to be adhered, or by pressing after touching the portion to be adhered, the portion to be adhered can be adhered. An adhesive may be, for example, a frit glass. 
   In each of the above mentioned inventions, it is preferable that the jig includes a sliding portion. The relative positions of a face plate and a rear plate can be set such that either the face plate or the rear plate can touch a sliding member, but it is more preferable that a plate side jig is provided for a face plate or a rear plate, or for both face plate and rear plate such that the plate side jig (corresponding to a face plate fixing plate in the embodiments described below) can touch another portion of a jig (a positioning jig to which a sliding pole corresponds in the embodiments described below). 
   That is, in each of the above mentioned inventions, either the face plate or the rear plate, or the plate side jig attached to either of them can be moved as touching the positioning jig while a movement in the interval direction is made while suppressing the misalignment between the face plate and the rear plate in a direction within a plane of the plates. 
   Furthermore, in each of the above mentioned inventions, it is preferable that the jig, the face plate, and the rear plate have substantially equal expansion coefficients at a heating temperature when the adhering step is performed. 
   In addition, in each of the above mentioned inventions, it is preferable that the flat panel display includes an electron emitting portion and a fluorescent member which becomes fluorescent by an electron emitted by the electron emitting portion. Particularly, it is preferable that the electron emitting portion is provided in the rear plate portion, and the fluorescent member is provided in the face plate portion. 
   In each of the above mentioned inventions, a support member for maintaining an interval between the face plate portion and the rear plate portion can be provided between the face plate portion and the rear plate portion. The support member can be preferably a member covered with a conductive film. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  shows a step of the method for producing a flat panel display according to the present invention; 
       FIG. 2  shows a step of the method for producing a flat panel display according to the present invention; 
       FIG. 3  shows a step of the method for producing a flat panel display according to the present invention; 
       FIG. 4  shows a step of the method for producing a flat panel display according to the present invention; 
       FIG. 5  shows a step of the method for producing a flat panel display according to the present invention; 
       FIG. 6  shows a step of the method for producing a flat panel display according to the present invention; 
       FIG. 7  shows a step of the method for producing a flat panel display according to the present invention; 
       FIG. 8  shows a step of the method for producing a flat panel display according to the present invention; 
       FIG. 9  shows a step of the method for producing a flat panel display according to the present invention; 
       FIG. 10  shows a step of the method for producing a flat panel display according to the present invention; 
       FIG. 11  shows a step of the method for producing a flat panel display according to the present invention; 
       FIG. 12  shows a step of the method for producing a flat panel display according to the present invention; 
       FIG. 13  is an explanatory view of a conventional technology; 
       FIG. 14  is an explanatory view of a conventional technology; 
       FIG. 15  is an explanatory view of a conventional technology; 
       FIG. 16  is an explanatory view of a conventional technology; 
       FIG. 17  is an explanatory view of a conventional technology; 
       FIG. 18  is an explanatory view of a conventional technology; 
       FIG. 19  is an explanatory view of a conventional technology; 
       FIG. 20  is an explanatory view of a conventional technology; 
       FIG. 21  is an explanatory view of a conventional technology, and 
       FIG. 22  is an explanatory view of a conventional technology. 
   

   BEST MODE FOR CARRYING OUT THE INVENTION 
   First, in the producing method shown in  FIGS. 13 through 22 , it can be assumed that a frit glass to be heated at 400° C. to 450° C. is used when a face plate and a rear plate are adhered and fixed to guarantee the air-tightness to maintain the heat-resistance and vacuum required when a heat-aging process and a baking processes are performed in the subsequent steps. 
   It is also assumed that an atmospheric-pressure-resistant support member is provided in the flat panel display to stand the atmospheric pressure. The frit glass of the frame portion is formed thicker before the heating process than after the heating process as shown in  FIG. 16  to guarantee the strength and the air-tightness so that the adhered layer can be formed by thinning it by the heating and pressing operations. The thickness depends on the structure and the size of the member, but is about 0.5 to 2 mm. Since the frit glass has a subtraction allowance, the face plate and the rear plate are aligned at the room temperature, and the discrepancy in position in the XY direction arises when the frit glass becomes lower in the method in which the heating process is performed after the fixing using a clip, etc., thereby making it difficult to obtain a flat panel display with high position precision. 
   Plate heaters above and below the face plate and the rear plate evenly heat them when they are aligned. Then, the frit glass is softened and then pressed, the aligning process is performed, the temperature is evenly lowered, and the aligning process is continued until the frit glass is hardened. Thus, the process of obtaining a flat panel display with-high position precision requires a complicated and costly system, and a long processing time. 
   Furthermore, as disclosed by Japanese Patent Application Laid-Open No. 9-50767, a fine groove is made on the display portion of the substrate to perform an aligning process through insertion. However, the process of making a groove is complicated and costly, and cannot attain a sufficient fixing effect because the depth of the groove is small. 
   The embodiment of the present invention described below has been developed to solve the above mentioned problem. 
   The preferred embodiment of the method for producing the flat panel display according to the present invention is described below by referring to the attached drawings. 
   The embodiment is an example of producing an image generation device using a surface conductive electron emission element. 
     FIGS. 1 through 12  sequentially show the producing process according to the present embodiment. 
   In  FIG. 1 , an inorganic adhesive  2  containing silver powder is applied to an application stand  1 , and an applicator  3  forms a thin layer  4  of a conductive adhesive. 
   The silver powder is an average of 3 to 5 micron grain, and the inorganic adhesive is a reactive silicates adhesive. According to the present embodiment, the heat-resistant inorganic adhesives ‘Aron Ceramic W’ (commercially available) of Toagosei Co., Ltd. in an average of 3 to 5 micron grain is used. The silver powder and the inorganic adhesive are mixed at the weight ratio of 20:80, and used as a conductive adhesive. 
   Then, an atmospheric-pressure-resistant support member  7 , which is 0.2 mm thick and has a conductive layer on the surface, is set at predetermined intervals by a jig  5  having a chucking member  6  (FIG.  2 ), and the thin layer  4  of the conductive adhesive touches one end of the atmospheric-pressure-resistant support member  7  (FIG.  3 ). By raising the jig  5 , a conductive adhesive lump  8  is formed at the end of the atmospheric-pressure-resistant support member  7  (FIG.  4 ). 
   Then, the atmospheric-pressure-resistant support member  7 , at whose end the conductive adhesive pit  8  is formed by the jig  5 , is set over a rear plate  9  fixed on a heating stand  11 , and touches an upper wiring  10  of the driving XY matrix wiring on the rear plate  9  (FIGS.  5  and  6 ). 
   The conductive adhesive touches the upper wiring  10  of the driving XY matrix wiring on the heated rear plate  9 , is heated up to 200° C., and is hardened. At this time, the indium metal powder in the conductive adhesive is fused, and the atmospheric-pressure-resistant support member  7  is fixed on the upper wiring  10  of the driving XY matrix wiring on the rear plate  9 , and electrically connected. 
   After hardening the conductive adhesive, the jig  5  is raised, and the rear plate  9  is removed from the heating stand. Thus, a rear plate  12  is obtained by fixing the atmospheric-pressure-resistant support member  7  on the upper wiring  10  of the driving XY, matrix wiring (FIGS.  7  and  8 ). 
   Then, an insulating frit glass  20  for adhering the frame is applied to the portion onto which the frame touches on a face plate substrate  14  on which a black stripe  16 , which is a stopping member, an RGB fluorescent object  17 , and a voltage applying metal back  18  are formed on a face place glass substrate  15 . The applied insulating frit glass  20  is dried, and provisionally sintered. 
   The rear plate material  12  on which the atmospheric-pressure-resistant support member  7  is fixed at a predetermined position, a frame  19  on which an insulating frit glass  13  is applied on the rear plate side, dried, and provisionally sintered, and the face plate substrate  14  to which the insulating frit glass  20  for adhering the frame is applied, dried, and provisionally sintered are set at predetermined positions (FIG.  9 ). 
   The positions of the face plate  14  and the rear plate  9  are set in the X and Y directions by a face plate fixing jig  29  and a rear plate fixing jig  28 . In this case, a face plate alignment mark  31  and a rear plate alignment mark  32  are aligned by monitoring through a CCD camera  30 , and fixed by a fixing jig  24  movable in the thickness direction (FIG.  10 ). 
   The fixing jig  24  movable in the thickness direction comprises a rear plate fixing plate  25 , a face plate fixing plate  26 , and a sliding pole  27 . The sliding pole  27  is fixed to the rear plate fixing plate  25 , and the face plate fixing plate  26  moves up and down along the hole into which the sliding pole  27  fits. These fixing jigs are made of ceramics (‘Photoveel’ preferably) which can be cut and have substantially the same expansion coefficient as the glass substrate used for the face plate  14  and the rear plate  9 . The rear plate fixing plate  25  is adhered to the rear plate  9  with the inorganic adhesive, and is then aligned. Then, the face plate fixing plate  26  is adhered to the face plate  14 . 
   The face plate  14  and the rear plate  9  fixed by the fixing jig  24  movable in the thickness direction are heated up to the temperature at which the frit glass is softened. The entire panel is pressed such that the frit glasses  13  and  20  at portions of the frame  19  can be spread to obtain the strength and the air-tightness. After the spread, the glasses are cooled, and a flat panel display  21  is obtained (FIGS.  11  and  12 ). 
   According to the present invention, the position discrepancy does not occur in the XY direction unlike the conventional technology when the frit glasses are lowered, thereby successfully producing an image forming apparatus with high position and size precision in a short-time process and a simple method. 
   As described above, according to an embodiment of the present invention, a face plate and a rear plate are aligned, they are fixed with a fixing jig movable in the thickness direction of a flat panel display, the rear plate, the face plate, and the frame member are heated up to the adhering temperature, and a load is applied in the thickness direction of the flat panel display to cause adhesion, thereby easily producing the apparatus with high precision. 
   In addition, in a method in which an assembling process is performed by providing aligning means, such as penetration hole, on the face plate or the rear plate after providing a fluorescent member, an acceleration electrode, an electron emission element, wiring, etc. on the face plate and the rear plate, it is necessary to mechanically form a hole, etc. in a glass substrate. The machining precision for a glass substrate within an error of +50 micron is quite difficult. In the above mentioned embodiments, after a face plate and a rear plate are aligned, they are fixed with a fixing jig movable in the thickness direction of a flat panel display, the rear plate, the face plate, and the frame member are heated up to the adhering temperature, and a load is applied in the thickness direction of the flat panel display to cause adhesion. The plate side jig and the sliding pole can slide without providing a sliding portion for the face plate or the rear plate. Therefore, the position precision in assembling can be obtained with an error of +10 micron. 
   Furthermore, by using the jig described by referring to the above mentioned embodiments, the alignment can be preferably performed between a face plate and a rear plate. As a result, once the face plate, the rear plate, and the jig are positioned at predetermined relative positions, the face plate and the rear plate can be separate, a vacuum chamber is exhausted, and then an adhering step is performed, thereby easily setting the atmosphere in the flat panel display in a preferable state. Even after separating the face plate from the rear plate, the aligned status can easily be realized for successful adhesion. 
   As described above by referring to a practical embodiment, the present invention can provide a preferred method for producing a flat panel display. 
   INDUSTRIAL APPLICABILITY 
   The present invention can be effectively utilized in the field of a flat panel display, and can easily produce flat panel displays with high precision.