Patent Publication Number: US-2006007165-A1

Title: Input-sensor-intergrated liquid crystal display panel

Description:
BACKGROUND OF INVENTION  
      1. Field of the Invention  
      The present invention relates to a liquid crystal display panel, and more particularly to a liquid crystal display having integrated input sensor.  
      2. Description of the Prior Art  
      Nowadays, liquid crystal displays with touch panel have been widely used as a medium of data communication in each scope of consuming electric products, such as personal digital assistant (PDA), mobile phone, notebook and tablet PC and other portable electric products. In addition, as a result of that the present design of electric products tends to be light, thin, and tiny, there is not enough space for installing keyboard, mouse and other traditional input components. The requirement of tablet PC with human-friendly design has further pushed touch panel to become one of the most important computer components. A touch panel not only satisfies the requirement of performing multi-layer menu design, but also has the functions of being a keyboard or a mouse. More practically, the functions of inputting and outputting signals are integrated within the same medium (screen). These advantages make the touch panel be superior to other traditional input components.  
       FIG. 1  is a schematic diagram of a traditional touch panel for a display device. The traditional touch panel  100  is consisted of a liquid crystal display panel and a detecting panel. The liquid crystal display panel includes a bottom substrate  102 , an upper substrate  104 , a liquid crystal layer  110 , color filters  108  and polarizers  112  and  114  disposed on the outside surface of the bottom substrate  102  and the upper substrate  104  separately. The pixel controlling circuit  118  is to control the liquid crystal molecular of the liquid crystal layer  110  with an angle so that the color filter  108  can display different color and brightness effect in accordance with light permeability. The detecting panel includes a glass substrate  106  and a detecting layer  116 . The detecting layer  116  has a touch-detecting circuit detecting contacts, touches and motions from fingers or other pointers.  
      The traditional touch panel  100  made by stacking up a liquid crystal display panel and a detecting panel has the function of detecting touch signals. However, the stake of the two panels reduces optical quality, for instance, the decrease of light-permeability or the increase of reflection rate. Besides, the traditional touch panel might not be wildly acceptable due to the heavy weight.  
     SUMMARY OF INVENTION  
      It is therefore a primary objective of the claimed invention to provide a liquid crystal display panel having integrated input sensor to solve the aforementioned problem. In the invention, a single liquid display panel can provide the functions of displaying images and detecting touch signals.  
      In accordance with the claim, an input-sensor-integrated liquid crystal display is disclosed. The liquid crystal display comprises a first substrate, a second substrate, a color filter and a liquid crystal layer. The first substrate has at least one pixel controlling circuit, and the second substrate has a touch-detecting circuit. The liquid crystal layer is filled in the space formed by the first substrate and the second substrate.  
      The invention may be understood by reference to the following description of an illustrative embodiment. However, it should be mentioned that the preferred embodiment is only for reference and description instead of limiting the present invention. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
       FIG. 1  is schematic diagram of a traditional touch panel for a display device according to prior art.  
       FIG. 2  and  FIG. 3  are schematic diagrams of the first preferred embodiment according to the present invention.  
       FIG. 4  and  FIG. 5  are schematic diagrams of input-sensor-integrated liquid crystal display panels according to the present invention.  
       FIG. 6  is a schematic diagram of the second preferred embodiment according to the present invention.  
       FIG. 7  is a schematic diagram of the third preferred embodiment according to the present invention. 
    
    
     DETAILED DESCRIPTION  
      Please refer to  FIG. 2 .  FIG. 2  is a schematic diagram of a preferred embodiment. A liquid crystal display panel  200  includes a bottom substrate  202 , a top substrate  204 , and a liquid crystal layer  210 . The top substrate  204  is positioned on top of the bottom substrate in parallel. The liquid crystal layer  210  is filled between the top substrate  204  and the bottom substrate  202 . The bottom substrate  202  has a pixel controlling circuit  218  for controlling pixels on and off. The color filter is positioned above the pixel controlling circuit  218  for filtering lights through the liquid crystal display panel  200  and ensuring that each pixel performs proper color. The pixel controlling circuit  218  and color filter  208  are fabricated on the same substrate by the color filter on array process (COA) technique. Therefore, more surface space is reserved for other application on the top substrate  204 .  
      In the present embodiment, the top substrate  204  has a detecting layer  216  with touch-detecting circuit that can detect touches and motions of fingers or touch pointers. The touch-detecting circuit is a resistance detecting circuit, capacitance detecting circuit, sound wave detecting circuit, or optical detecting circuit. In addition, the liquid crystal display  200  further comprises polarizer  212  and polarizer  214  positioned on the outer surfaces of the top substrate  202  and the bottom substrate  204 . Apart from positioning the detecting layer  216  on the inner surface of the top substrate  204  facing the bottom substrate  202 , as shown in  FIG. 2 , the detecting layer  216  is positioned on the outer surface of the top substrate  204  not facing the bottom surface  202 , as shown in  FIG. 3 . In  FIG. 3  the detecting layer  216  is positioned on the outer surface of the top substrate  204  not facing the bottom substrate  202 , i.e. the detecting layer  216  is between the top substrate  214  and the polarizer  214 .  
      In accordance with the bottom substrate  202  having pixel controlling circuit  218  and the top substrate  204  having detecting layer (tough-detecting circuit)  216 , the bottom substrate  202  and the top substrate  204  have to have signal contacts to transmit every kind of pixel controlling signals and touch-detecting signals. To achieve the demand, the top substrate  204  is not designed to coincide with the bottom substrate  202  completely for setting signal connecting contacts. For instance, the top substrate  204  has at least one protrusion  206  jutting out the bottom substrate  202  and the bottom substrate  202  has at least one protrusion jutting out the top substrate  204 . Consequently, the structure is constructed as shown in the  FIG. 4  and  FIG. 5 . In the  FIG. 4  and  FIG. 5 , the top substrate  202  and the bottom substrate  204  have at least one edge jutting out another substrate for installing signal connecting contacts and connecting to controlling or detecting circuit outside.  
      Please refer to the  FIG. 6 .  FIG. 6  is a schematic diagram of the second illustrative embodiment. The liquid crystal display panel  300  includes a bottom substrate  302 , a top substrate  304  and a liquid crystal layer  310 . A pixel controlling circuit is fabricated on the bottom substrate  302 , a color filter  308  is fabricated on the inner surface of the top substrate  304  facing the bottom substrate  302 , and a detecting layer  316  is disposed on the outer surface of the top substrate  304  not facing the bottom substrate  302 . The liquid crystal layer  310  is filled between the top substrate  304  and the bottom substrate  302 . The detecting layer  316  has a touch-detecting circuit detecting touch and motion signals from fingers or touch pointers. The touch-detecting circuit is a resistance detecting circuit, capacitance detecting circuit, sound wave detecting circuit, or optical detecting circuit. The liquid crystal display further comprises polarizer  314  and polarizer  312  positioned on the outer surfaces of the bottom substrate  302  and the top substrate  304  separately.  
      In the present embodiment, the detecting layer  316  and the color filter  308  is fabricated on the two sides of the top substrate  304  to make the top substrate  304  have functions of displaying images and detecting signals. The bottom substrate  302  and the top substrate  304  are designed to have at least one edge jutting out the edge of the other substrate for setting signal connecting contacts and connecting controlling circuit or detecting circuit outside.  
      Please refer to  FIG. 7 .  FIG. 7  is a schematic diagram of the third preferred embodiment. The structure of the liquid crystal display panel  400  is similar to the aforementioned liquid crystal display panel  300 , wherein the detecting layer  416  and the color filter  408  are fabricated on the top substrate  404 . The difference is that the detecting layer  416  and the color filter  408  are fabricated on the same side of the top substrate  404 .  
      As shown in  FIG. 7 , the liquid crystal display panel  400  includes a bottom substrate  402 , a top substrate  404 , and a liquid crystal layer  410 . A pixel controlling circuit  418  is disposed on the bottom substrate  402 . A color filter  408  and a detecting layer  416  are fabricated on the top substrate  404 . The detecting layer  416  has a touch-detecting circuit detecting touches and motions of fingers or other pointers. The touch-detecting circuit is a resistance detecting circuit, capacitance detecting circuit, sound wave detecting circuit, or optical detecting circuit. The color filter  408  is positioned on the surface of the detecting layer  416  and the liquid crystal layer  410  is between the top substrate  404  and the bottom substrate  402 . In addition, the liquid crystal display panel further comprises polarizer  412  and polarizer  414  positioned on the outer surfaces of the bottom substrate  402  and the top substrate  404  separately.  
      For a convenient design of signal connecting contacts, at least one protrusion is made at the bottom substrate  402  and the top substrate  404  for setting signal connecting contacts and connecting controlling circuit or detecting circuit outside.  
      Compared with the traditional touch panel for a display device, the present input-sensor-integrated liquid crystal display panel has the advantage of integrating a touch-controlling circuit into liquid crystal display panel. In another words, the liquid crystal display panel not only displays images but also detects touch signals. Therefore, the prior art problems of the decrease of optical quality and the heavy product weight can be solved in accordance with the invention.  
      Those skilled in the art will readily observe that numerous modifications and alterations of the device may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.