Abstract:
An in-cell touch liquid crystal display module includes a first glass substrate, a metal film disposed on the first glass substrate, a liquid crystal layer disposed on the metal film, a second glass substrate disposed on the liquid crystal layer, a conductive layer disposed on the second glass substrate for generating a sensing signal in response to a touch of the conductive layer, a flexible circuit board comprising a plurality of wires coupling the conductive layer, for transmitting the sensing signal, a conductive adhesive for adhering and fastening the flexible circuit board on the second glass substrate, and an insulating adhesive disposed on an periphery of the first glass substrate, for adhering the flexible circuit board on the first glass substrate.

Description:
CLAIM OF PRIORITY 
       [0001]    This application is a continuation of U.S. patent application Ser. No. 12/580,423 filed on Oct. 16, 2009, which claims priority to Taiwanese Patent Application No. 098117212 filed on May 22, 2009. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to a touch panel liquid crystal display (touch panel LCD), and more particularly, to a touch panel liquid crystal display with an in-cell touch liquid crystal display module. 
         [0004]    2. Description of Prior Art 
         [0005]    With a rapid development of monitor types, novel and colorful monitors with high resolution, e.g., liquid crystal displays (LCDs), are indispensable components used in various electronic products such as monitors for notebook computers, personal digital assistants (PDAs), digital cameras, and projectors. The demand for the novelty and colorful monitors has increased tremendously. 
         [0006]    In order to facilitate the carrying and utilization of current LCDs, touch LCD panels that users can touch directly have become a new trend in market development. LCD touch panels which are applied to PDAs are usually combined with LCDs and touch panels to omit keyboard or functional buttons. LCD touch panels usually generate electric signals in response to a touch thereon to control image display of LCDs and implement function control. 
         [0007]    Traditional LCD modules employ tapes to paste a LCD panel and a touch panel together as a whole. One end of a flexible printed circuit board (FPC) is connected to a touch panel. But, because the press-fit area between the FPC and the touch panel is quite small, the FPC is inclined to be delaminated from the press-fit area of the touch panel or to be fractured due to minor external forces through the process of assembling. Besides, sometimes, driver integrated circuits (ICs) and other passive elements are disposed on an FPC, and their weight is usually much heavier than that of a single FPC. If an FPC is supported only by the limited press-fit area between an FPC and a touch panel, it is inclined to get loose, resulting in failing to pass strict drop and vibration tests. If an FPC cannot be effectively fastened, defective yield will thus be extremely high, and further, material losses such as FPCs and touch panel driver ICs will be produced. 
       BRIEF SUMMARY OF THE INVENTION 
       [0008]    It is therefore an object of the present invention to provide an in-cell touch liquid crystal display module which intensifies fixation between an FPC and a touch panel to overcome shortcomings occurring in prior art that a touch panel and an FPC cannot be fastened or easily assembled together. 
         [0009]    According to one aspect the present invention, an in-cell touch liquid crystal display module comprises a first glass substrate, a metal film disposed on the first glass substrate, a liquid crystal layer disposed on the metal film, a second glass substrate disposed on the liquid crystal layer, a conductive layer disposed on the second glass substrate for generating a sensing signal in response to a touch of the conductive layer, a flexible circuit board comprising a plurality of wires coupling the conductive layer, for transmitting the sensing signal, and an insulating adhesive disposed on an periphery of the first glass substrate, for adhering the flexible circuit board on the first glass substrate. 
         [0010]    According to another aspect the present invention, an in-cell touch liquid crystal display module comprises a first glass substrate, a metal film disposed on the first glass substrate, a liquid crystal layer disposed on the metal film, a second glass substrate disposed on the liquid crystal layer, a conductive layer disposed on the second glass substrate, for generating a sensing signal in response to a touch of the conductive layer, a flexible circuit board comprising a plurality of wires coupling the conductive layer, for transmitting the sensing signal, an conductive adhesive for adhering the flexible circuit board on the second glass substrate to couple the plurality of wires with the flexible circuit board. 
         [0011]    According to still another aspect of the present invention, a method of manufacturing an in-cell touch liquid crystal display module comprises the following steps: [0012] (a) providing a first glass substrate; [0013] (b) forming a metal film on the first glass substrate; [0014] (c) providing a second glass substrate; [0015] (d) forming a conductive layer on a top of the second glass substrate and a color filter layer on a bottom of the second glass substrate; [0016] (e) forming a liquid crystal layer between the first glass substrate and the second glass substrate; [0017] (f) aligning and jointing the first glass substrate and the second glass substrate; [0018] (g) providing an insulating adhesive on a periphery of the first glass substrate; [0019] (h) providing a conductive adhesive on the conductive layer; and [0020] (i) adhering a first polarizer and a second polarizer on a top surface of the conductive layer and a bottom surface of the first glass substrate; [0021] (j) providing and pressing a flexible circuit board, so that the flexible circuit board is adhered and fastened to the first glass substrate and the conductive layer by employing the insulating adhesive and the conductive adhesive, respectively. 
         [0012]    According to still another aspect of the present invention, an in-cell touch liquid crystal display module comprises a array substrate, a color filter correspondingly disposed on the array substrate, a liquid crystal layer disposed between the array substrate and the color filter, a conductive layer disposed on the color filter, and the color filter sandwiched between the liquid crystal layer and the conductive layer, a flexible circuit board, an anisotropic conductive film disposed on a periphery of the conductive layer, for adhering and fastening the flexible circuit board on the conductive layer. 
         [0013]    These and other objectives of the present invention will become apparent to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0014]      FIG. 1  demonstrates a side view of an in-cell touch liquid crystal display module of a touch liquid crystal display device according to one embodiment of the present invention; 
           [0015]      FIG. 2  shows a top view of the in-cell touch liquid crystal display module in  FIG. 1 ; 
           [0016]      FIGS. 3A and 3B  illustrate a flexible printed circuit board, an insulating adhesive, and a array substrate of the in-cell touch liquid crystal display module in  FIG. 2  from two different angles; 
           [0017]      FIG. 4  is a flow chart of the in-cell touch liquid crystal display module of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0018]    Referring to the attached figures, the following embodiments are illustrated to exemplify certain embodiments that the present invention can be applied to. The directional terms adopted in the present invention, such as upper, lower, front, back, left, right, top, and bottom, are defined merely according to the attached figures. Hence, the usage of the directional terms is to assist in elaborating, instead of confining, the present invention for better understanding. 
         [0019]    Referring to  FIG. 1  as well as  FIGS. 2 ,  3 A, and  3 B,  FIG. 1  demonstrates a side view of an in-cell touch liquid crystal display module  200  of a touch liquid crystal display device according to one embodiment of the present invention;  FIG. 2  shows a top view of the in-cell touch liquid crystal display module  200  in  FIG. 1 ;  FIGS. 3A and 3B  illustrate a flexible printed circuit board (FPC)  220  and an insulating adhesive  222  of the in-cell touch liquid crystal display module  200  in  FIG. 2  from two different angles. The in-cell touch liquid crystal display module  200  comprises an array substrate  201 , a liquid crystal layer  206 , a second glass substrate  208 , a conductive layer  210 , a color filter  212 , an FPC  220 , a first polarizer  260 , a second polarizer  262 , and an insulating adhesive  222 . The array substrate  201  comprises a first glass substrate  202  and a metal film  204  on a top surface of the first glass substrate  202 . Furthermore, a second polarizer  262  is formed on a bottom surface of the first glass substrate  202 . The first glass substrate  202  and the metal film  204  can be regarded as an array substrate  201  which is installed with a plurality of matrix-arranged pixel elements. The liquid crystal layer  206  is disposed between the array substrate  201  and the color filter  212 . Corresponding to the array substrate  201 , the color filter  212  causes the light that penetrates into the liquid crystal layer  206  to show three different colors—red (R), green (G), and blue (B). The first polarizer  260 , the second glass substrate  208  and the conductive layer  210  form an in-cell touch panel  230 . The in-cell touch panel  230  connects to the first glass substrate  202  by using sealant  214 . The FPC  220  comprises a detecting circuit  242  and a plurality of wires  240  coupled to the conductive layer  210 . When a certain position of the conductive layer  210  of the in-cell touch panel  230  is pressed by an external force, a sensing signal is generated by the conductive layers  210  according to the position of point of application of force. After the sensing signal is transmitted to the detecting circuit  242  through the wires  240 , the detecting circuit  242  can resolve the coordinate of the point of application of force corresponding to the in-cell touch panel  230 . A conductive adhesive  224  (e.g., anisotropic conductive film, ACF) is disposed on a periphery of the conductive layer  210  to adhere and fasten the FPC  220  to the top of the conductive layers  210  and then to facilitate electric signals (e.g. sensing signals) with electrical properties generated by the conductive layer  210  being transmitted to the wires  240 . 
         [0020]    Moreover, in order to make certain that the FPC  220  and the array substrate  201  are well fastened, the insulating adhesive  222  is disposed on the periphery of the first glass substrate  202  to adhere and fasten the FPC  220  to the first glass substrate  202 . Preferably, the insulating adhesive  222  can be transparent double-sided tape when aesthetics and costs are taken into consideration. Double-sided tape comprises a first adhesion layer  2221 , a second adhesion layer  2222 , and a base layer  2224  disposed therebetween. In one embodiment of the present invention, both of the first adhesion layer  2221  and second adhesion layer  2222  may be made from tackified acrylic; the base layer  2224  may be composed of polyethylene terephthalate (PET). Generally speaking, the total thickness of the metal film  204 , the liquid crystal layer  206 , the color filter  212 , the second glass substrate  208 , the conductive layer  210 , and the conductive adhesive  224  is roughly between 15 .mu.m and 30 .mu.m. In this embodiment, the total thickness of the metal film  204  (4.5 .mu.m), the liquid crystal layer  206  (3.5 .mu.m), the color filter  212  (1 .mu.m), the second glass substrate  208  (500 .mu.m), the conductive layer  210  (3.625 .mu.m), and the conductive adhesive  224  (18 .mu.m) is about 530.625 .mu.m. In order to protect the FPC  220  from bending after being fastened to the array substrate  201 , the thickness of the insulating adhesive  222  should lie between 40 .mu.m and 550 .mu.m. For example, the thickness of Tesa 4972 is about 48 .mu.m. In a preferred embodiment, the thickness of the insulating adhesive  222  is equal to the total thickness of the metal film  204 , the liquid crystal layer  206 , the color filter  212 , the second glass substrate  208 , the conductive layer  210 , and the conductive adhesive  224 . But practically, the present invention also allows the thickness of the insulating adhesive  222  to extend slightly above 550 .mu.m or below 40 .mu.m. In addition, even if the periphery of the metal film  204  partially overlaps with the insulating adhesive  222 , the effect of the present invention remains intact. 
         [0021]    Referring to  FIG. 1  and  FIG. 4 ,  FIG. 4  is a flow chart of the in-cell touch liquid crystal display module of the present invention. The method of the present invention comprises the following steps: [0032] Step  402 : Provide a first glass substrate  202 . [0033] Step  404 : Form a metal film  204  on the first glass substrate  202 . [0034] Step  406 : Provide a second glass substrate  208 . [0035] Step  408 : Form a conductive layer  210  on a top of the second glass substrate  208  and a color filter layer  212  on a bottom of the second glass substrate. [0036] Step  410 : Form a liquid crystal layer  206  between the first glass substrate  202  and the second glass substrate  208 . [0037] Step  412 : Align and joint the first glass substrate  202  and the second glass substrate  208 . [0038] Step  414 : Provide the periphery of the first glass substrate  202  with an insulating adhesive  222 . [0039] Step  416 : Provide the conductive adhesive  224 . [0040] Step  417 : Adhere a first polarizer  260  and a second polarizer  262  on a top surface of the conductive layer  210  and a bottom surface of the first glass substrate  202 , respectively. [0041] Step  418 : Provide and press an FPC  220 , so that the FPC  220  is adhered and fastened to the first glass substrate  202  and the conductive layer  210  by employing the insulating adhesive  222  and the conductive adhesive  224 , respectively. [0042] Step  420 : Test if sensing signals are generated by the conductive layer  210  and transmitted to the FPC  220 . If so, perform Step  432 ; if not, perform Step  422 . [0043] Step  422 : Remove the FPC  220  from the first glass substrate  202  and the conductive layer  210 . [0044] Step  424 : Clear up the insulating adhesive  222  and the conductive adhesive  224 . [0045] Step  426 : Provide the periphery of the first glass substrate  202  with another insulating adhesive  222 . [0046] Step  428 : Provide another conductive adhesive  224 . [0047] Step  430 : Provide and press another FPC  220 , so that the FPC is adhered and fastened to the first glass substrate  202  and the conductive layer  210  by employing the insulating adhesive  222  and the conductive adhesive  224 , respectively. [0048] Step  432 : Move on to the next manufacturing process. 
         [0022]    In contrast to prior art, an FPC of an in-cell touch liquid crystal display module in the present invention is adhered and fastened to a first glass substrate (or an array substrate) and a conductive layer (i.e., a touch panel) by employing an insulating adhesive and a conductive adhesive, respectively. Therefore, the FPC can be adhered to the matrix substrate better and less inclined to fall off, especially, through the process of assembling a whole liquid crystal display module. In this way, the defective fraction during manufacture of in-cell touch liquid crystal display modules can be decreased. 
         [0023]    It is to be understood, however, that 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, and 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.