Abstract:
A capacitive touch panel sequentially has a first glass substrate, a lower touch sensitive layer, a lower insulation ink layer, a lower conductor layer, a lower insulation layer, a lower conductive adhesive layer, a flexible circuit board, a transparent insulation adhesive layer, an upper insulation layer, an upper conductive adhesive layer, an upper conductor layer, an upper insulation ink layer, an upper touch sensitive layer and a second glass substrate. The aforementioned structure allows fabrication of the capacitive touch panel to be separated into a lower panel fabrication process and an upper panel fabrication process. The two independent fabrication processes prevent the capacitive touch panel from being damaged in one of the processes when the process is completed so as to increase the yield in production and further facilitate producing large-size touch panel.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention is related to a capacitive touch panel, and more particularly to a capacitive touch panel having a relatively high yield in production and being suitable for manufacture of large-size touch panel. 
     2. Description of the Related Art 
     Existing touch panels can be classified as resistive touch panels and capacitive touch panels. Recently, the capacitive touch panels become increasingly popular in the market. 
     With reference to  FIG. 3 , a conventional touch panel has a first glass substrate  61 , a lower touch sensitive layer  62 , an upper touch sensitive layer  63 , a flexible circuit board  64 , a transparent insulation adhesive layer  65  and a second glass substrate  66 . The first glass substrate  61  has a top surface and a bottom surface. The upper touch sensitive layer  63  and the lower touch sensitive layer  62  are respectively formed on the top surface and the bottom surface of the first glass substrate  61 . The flexible circuit board  64  is mounted on the top surface of the first glass substrate  61  and is partially and electrically connected with the upper touch sensitive layer  63 . The transparent insulation adhesive layer  65  is coated on the first glass substrate  61 . The second glass substrate  66  is covered and bonded on the transparent insulation adhesive layer  65 . 
     However, the conventional technology can only separately forms the upper touch sensitive layer  63  and the lower touch sensitive layer  62  on the top and the bottom surfaces of the first glass substrate  61 , for example, forming the upper touch sensitive layer  63  first. Hence, when the lower touch sensitive layer  62  is formed subsequently, the completed upper touch sensitive layer  63  is easily scratched or stained during a fabrication process of the lower touch sensitive layer  62 . As a result, the production yield is significantly lowered. Because of the low yield, such capacitive touch panels do not aim for large-size touch panel, thereby further limiting the application range thereof. Furthermore, as being exposed without any protection, the lower touch sensitive layer  62  is easily collided and damaged. 
     SUMMARY OF THE INVENTION 
     An objective of the present invention is to provide a capacitive touch panel having a relatively high yield in production and being suitable for manufacture of large-size touch panel. 
     To achieve the foregoing objective, the capacitive touch panel has a first glass substrate, a lower touch sensitive layer, a lower insulation ink layer, a lower conductor layer, a lower insulation layer, a lower conductive adhesive layer, a flexible circuit board, a transparent insulation adhesive layer, an upper insulation layer, an upper conductive adhesive layer, an upper conductor layer, an upper insulation ink layer, an upper touch sensitive layer, and a second glass substrate. 
     The first glass substrate has a first circuit surface. 
     The lower touch sensitive layer is mounted on the first circuit surface of the first glass substrate. 
     The lower insulation ink layer is mounted on an edge portion of the lower touch sensitive layer so as to let an uncovered portion of the lower touch sensitive layer constitute a touch area, and has a plurality of lower through slots formed through an portion of the lower insulation ink layer covering the edge portion of the lower touch sensitive layer and each filled in with a lower conductive layer. 
     The lower conductor layer is mounted on the lower insulation ink layer and is electrically connected with the lower touch sensitive layer through the lower conductive layers filled in the corresponding lower through slots. 
     The lower insulation layer is mounted on the lower conductor layer and has a lower indentation to partially expose the lower conductor layer. 
     The lower conductive adhesive layer is mounted in the lower indentation of the lower insulation layer to cover the exposed portion of the lower conductor layer. 
     The flexible circuit board is mounted on the lower conductive adhesive layer, extends outwardly beyond the first glass substrate, and is electrically connected with the lower touch sensitive layer through the lower conductive adhesive layer and the lower conductive layers in the corresponding lower through slots. 
     The transparent insulation adhesive layer is mounted on the touch area and the lower insulation layer. 
     The upper insulation layer is mounted on the transparent insulation adhesive layer and has an upper indentation to expose the flexible circuit board. 
     The upper conductive adhesive layer is mounted in the upper indentation of the upper insulation layer to contact with the flexible circuit board. 
     The upper conductor layer is mounted on the upper conductive adhesive layer and the upper insulation layer. 
     The upper insulation ink layer is mounted on the upper conductor layer, and has a plurality of upper through slots formed through the upper insulation ink layer and each filled in with a upper conductive layer having a color identical to that of the upper insulation ink layer. 
     The upper touch sensitive layer is mounted on the transparent insulation adhesive layer, partially covers the upper insulation ink layer, and contacts with the upper conductive layers in the corresponding upper through slots of the upper insulation ink layer. 
     The second glass substrate is mounted on the upper touch sensitive layer and the upper insulation ink layer and has a second circuit surface in contact with the upper touch sensitive layer and the upper insulation ink layer. 
     Given the above-mentioned structure of the capacitve touch panel, the lower touch sensitive layer and the upper touch sensitive layer respectively contact with the first glass substrate and the second glass substrate. Upon fabricating the capacitive touch panel, the first glass substrate and the second glass substrate can be respectively mounted on the lower touch sensitive layer and the upper touch sensitive layer with different fabrication processes. As using sheet glass for fabrication of single-sided circuit layer is a mature technique, the resulting yield in production is relatively high, and the relatively high yield helps build large-size touch panel. 
     Other objectives, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exploded perspective view of a capacitive touch panel in accordance with the present invention; 
         FIG. 2  is a partial cross-sectional view of the capacitive touch panel in  FIG. 1 ; and 
         FIG. 3  is a cross-sectional view of a conventional capacitive touch panel. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     With reference to  FIGS. 1 and 2 , a capactive touch panel has a first glass substrate  11 , a lower touch sensitive layer  12 , a lower insulation ink layer  13 , a lower conductor layer  14 , a lower insulation layer  15 , a lower conductive adhesive layer  16 , a flexible circuit board  20 , a transparent insulation adhesive layer  30 , an upper insulation layer  41 , an upper conductive adhesive layer  42 , an upper conductor layer  43 , an upper insulation ink layer  44 , an upper touch sensitive layer  45 , a second glass substrate  46 , an upper protection layer  51  and a lower protection layer  52 . 
     The first glass substrate  11  has a first circuit surface  111 . 
     The lower touch sensitive layer  12  is mounted on the first circuit surface  111  of the first glass substrate  11 . In the present embodiment, the lower touch sensitive layer  12  has a lower touch circuit of a double-layer touch electrode layer, such as an X-axis touch circuit. 
     The lower insulation ink layer  13  is mounted on an edge portion of the lower touch sensitive layer  12  so that an uncovered portion of the lower touch sensitive layer  12  constitutes a touch area  131 . The lower insulation ink layer  13  has a plurality of lower through slots  132  formed through an portion thereof covering the edge portion of the lower touch sensitive layer  12 . A lower conductive layer  133  is filled in each lower through slot  132 . In the present embodiment, the lower insulation ink layer  13  is formed by printing and baking dark-color ink on the first circuit surface  111  of the first glass substrate  11 . The portion of the lower insulation ink layer  13  may be printed with or without dark-color ink. Accordingly, the lower conductive layer  133  adopts a conductive matter having a color identical to or different from that of the lower insulation ink layer  13  as the plurality of lower through slots  132  are invisible regardless due to all the layers stacked on the lower insulation ink layer  13  and the lower conductive layer  133 . 
     The lower conductor layer  14  is mounted on the lower insulation ink layer  13 , and is electrically connected with the lower touch sensitive layer  12  through the lower conductive layers  133  filled in the lower through slots  132 . 
     The lower insulation layer  15  is mounted on the lower conductor layer  14  to prevent the lower conductor layer  14  from being oxidized due to exposure to air. The lower insulation layer  15  has a lower indentation  151  to partially expose the lower conductor layer  14 . In the present embodiment, the lower insulation layer  15  is made of a transparent insulation material. 
     The lower conductive adhesive layer  16  is mounted in the lower indentation  151  of the lower insulation layer  15  to cover the exposed portion of the lower conductor layer  14 . In the present embodiment, the lower conductive adhesive layer is formed by anisotropic conductive film (ACF) or anisotropic conductive paste (ACP). 
     Upon fabricating the capacitive touch panel in accordance with the present invention, a lower panel fabrication process completing the first glass substrate  11 , the lower touch sensitive layer  12 , the lower insulation ink layer  13 , the lower conductor layer  14 , the lower insulation layer  15  and the lower conductive adhesive layer  16  can be conceived. 
     The flexible circuit board  20  has a top surface  21  and a bottom surface  22 . The flexible circuit board  20  is mounted on the lower conductive adhesive layer  16  and the bottom surface  22  is attached on the lower conductive adhesive layer  16  and extends outwardly beyond the first glass substrate  11 . The flexible circuit board  20  is electrically connected with the lower touch sensitive layer  12  through the lower conductive adhesive layer  16  and the lower conductive layers  133  in the lower through slots  132  of the lower insulation ink layer  13 . 
     The transparent insulation adhesive layer  30  has a thick portion  301  and a thin portion  302 . The thick portion  301  is mounted on the touch area  131  and the thin portion  302  is mounted on the lower insulation layer  15 . 
     The upper insulation layer  41  is mounted on the transparent insulation adhesive layer  30  and has an upper indentation  411  to expose the flexible circuit board  20 . 
     The upper conductive adhesive layer  42  is mounted in the upper indentation  411  of the upper insulation layer  41  to contact with the top surface  21  of the flexible circuit board  20 . 
     The upper conductor layer  43  is mounted on the upper conductive adhesive layer  42  and the upper insulation layer  41 . 
     The upper insulation ink layer  44  is mounted on the upper conductor layer  43  and has a plurality of upper through slots  441  formed through the upper insulation ink layer  44 . An upper conductive layer  442  is filled in each upper through slot  441  to contact with the upper conductor layer  43 . In the present embodiment, the upper conductive layer  442  adopts a conductive matter having a color identical to that of the upper insulation ink layer  44  to conceal the upper through slots  441 . 
     The upper touch sensitive layer  45  is mounted on the transparent insulation adhesive layer  30 , partially covers the upper insulation ink layer  44  and contacts with the upper conductive layer  442  in the upper through slots  441  of the upper insulation ink layer  44 . Accordingly, the upper touch sensitive layer  45  can be electrically connected with the flexible circuit board  20  through the upper conductive layers  442  in the upper through slots  441  of the upper insulation ink layer  44  and the upper conductive adhesive layer  42 . In the present embodiment, the upper touch sensitive layer  45  is composed of an upper touch circuit of a double-layer touch electrode layer, such as a Y-axis touch circuit. 
     The second glass substrate  46  is mounted on the upper touch sensitive layer  45  and the upper insulation ink layer  44 , and has a second circuit surface  461  in contact with the upper touch sensitive layer  45  and the upper insulation ink layer  44 . When viewed from a side opposite to the second circuit surface  461  of the second glass substrate  46 , the upper insulation ink layer  44  has a masking effect. 
     Upon fabricating the capacitive touch panel in accordance with the present invention, an upper fabrication process completing the upper insulation layer  41 , the upper conductive adhesive layer  42 , the upper conductor layer  43 , the upper insulation ink layer  44 , the upper touch sensitive layer  45  and the second glass substrate  46 . 
     With further reference to  FIG. 2 , the upper protection layer  51  is bonded to the top surface  22  of the flexible circuit board  20  and a side of the second glass substrate  46  to protect the flexible circuit board  20  from directly contacting with a side of the second glass substrate  46  when the flexible circuit board  20  is bent. Therefore, the flexible circuit board  20  is free from cut and damage done by the second glass substrate  46  upon bending. 
     The lower protection layer  52  is bonded to a side portion of the capacitive touch panel between the bottom surface  21  of the flexible circuit board  20  and the first glass substrate  11  to provide similar protection to the flexible circuit board  20  as the upper protection layer  51  does. 
     The present invention addresses the following advantages: 
     1. Fabrication of the capacitive touch panel of the present invention can be separated into a lower panel fabrication process and an upper panel fabrication process. According to skill level of the current technology, the yield of using sheet glass to fabricate single-sided circuit layer is high. Hence, the structure of the capacitive touch panel of the present invention has a better yield than conventional capacitive touch panels in production. 
     2. As the yield of the present invention in production is better, the capacitive touch panel of the present invention can be applied to the fabrication of large-size touch panel, achieving a wider application range. 
     3. The capacitive touch panel of the present invention is fabricated by forming the upper and lower insulation ink layer  44 ,  13  on the second circuit surface  461  of the second glass substrate  46  and the first circuit surface  111  of the first glass substrate  11  to respectively cover edges of the upper and lower touch sensitive layers  45 ,  12  and to mask the upper and lower conductor layers  43 ,  14 , the upper and lower insulation layers  41 ,  15  and the upper and lower conductive adhesive layers  42 ,  16  sandwiched between the upper and lower insulation ink layer  44 ,  13 . When the capacitive touch panel of the present invention is completed and assembled with a housing of an electronic product, the housing can be mounted on the second glass substrate  46  and the first glass substrate  11 , making the assembly and design of the capacitive touch panel of the present invention more convenient. 
     4. As the upper and lower touch sensitive layers  45 ,  12  and the upper and lower conductor layers  43 ,  14  are sandwiched between the first glass substrate  11  and the second glass substrate  46  without being exposed. Therefore, when shipping the capacitive touch panel of the present invention, damage of the upper and lower touch sensitive layers  45 ,  12  and the upper and lower conductor layers  43 ,  14  caused upon shipping can be avoided. 
     5. The lower conductive layer  133  can employ a conductive matter having a color identical to or different from that of the lower insulation ink layer  13  and such flexibility facilitates the choice and manufacture of the lower conductive layer  133  and the insulation ink layer  13 . 
     Even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only. Changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.