Abstract:
A display device detects a touched position by making use of a inducing element and a counter electrode. The voltage produced by the counter electrode is able to affect a conductivity of the channel of the inducing element corresponding to the touched position. The inducing element and a readout circuit are disposed on a substrate of the display device. The counter electrode and a shielding element are both corresponded to the inducing element. The channel of the inducing element corresponding to the touched position changes the conductivity due to the voltage produced by the corresponding counter electrode, and an inducing signal is then generated. The inducing signal is furnished to the readout circuit for signal processing, and a readout signal is generated for analyzing the touched position.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a display device and a related positioning method, and more particularly, to a liquid crystal display device and a related positioning method having input functionality. 
         [0003]    2. Description of the Prior Art 
         [0004]    Liquid crystal displays (LCDs) have been widely customized and become the most popular displays, because of their small size, low power consumption, and low radiation emissions. Among various types of electronic apparatuses, such as multimedia playbacks, mobile phones or personal digital assistants (PDAs), the electronic apparatus having a liquid crystal display with touch screen for performing input processes has gained popularity. 
         [0005]    Traditionally, the prior art touch screens are primarily classified into the resistive touch screens and the capacitive touch screens. The resistive touch screen positions a touched position according to related voltage drops changing in response to the touched position. The capacitive touch screen normally comprises a plurality of sensing capacitors, and the touched position can be positioned by analyzing the changing of capacitance of the sensing capacitor corresponding to the touched position. The prior art touch screen comprises a touch panel and a liquid crystal panel separately. The touch panel and the liquid crystal panel are fabricated individually and are assembled together to form the prior touch screen. Consequently, the prior art touch screen has disadvantages such as greater weight, higher cost, and lower light penetrating rate. In order to solve the aforementioned disadvantages, a touch screen having a display device and a touch device on a single panel is developed. 
       SUMMARY OF THE INVENTION 
       [0006]    In accordance with an embodiment of the present invention, a display device having input functionality is provided. The display device comprises a substrate, a data line, an inducing element, and a shielding element. The substrate has a pixel electrode and a first conductive line. The data line is disposed on the substrate and crosses the first conductive line. The inducing element is electrically connected to the first conductive line and is disconnected with the pixel electrode. The shielding element is disposed corresponding to the inducing element. 
         [0007]    Furthermore, the present invention provides a positioning method for a display device. The display device comprises a counter electrode, an inducing element, and a readout circuit. The positioning method comprises touching the display device in a position, changing a gap between the counter electrode and the inducing element for modulating a conductivity of the inducing element to a modulated conductivity of the inducing element corresponding to the position, generating an inducing signal based on the modulated conductivity of the inducing element, and furnishing the inducing signal to the readout circuit. 
         [0008]    These and other objectives of the present invention will no doubt become obvious 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 DRAWINGS 
         [0009]      FIG. 1  is a cross-sectional diagram schematically showing an inducing unit according to the present invention. 
           [0010]      FIG. 2  is a cross-sectional diagram schematically showing the deformation of the counter substrate of the inducing unit in  FIG. 1  when applying an external force to the counter substrate. 
           [0011]      FIG. 3  is a circuit diagram schematically showing an array structure based on the inducing unit in  FIG. 1  according to the present invention. 
           [0012]      FIG. 4  is a layout diagram schematically showing a panel structure according to the present invention. 
           [0013]      FIG. 5  is a schematic diagram showing a pixel unit according to the present invention. 
           [0014]      FIG. 6  is a circuit diagram schematically showing an inducing circuit according to the present invention. 
           [0015]      FIG. 7  is a circuit diagram schematically showing another array structure based on the inducing unit in  FIG. 1  according to the present invention. 
           [0016]      FIG. 8  is a circuit diagram schematically showing another array structure based on the inducing unit in  FIG. 1  according to the present invention. 
           [0017]      FIG. 9  is a circuit diagram schematically showing another array structure based on the inducing unit in  FIG. 1  according to the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0018]    Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Here, it is to be noted that the present invention is not limited thereto. Furthermore, the step serial numbers concerning the positioning method are not meant thereto limit the operating sequence, and any rearrangement of the operating sequence for achieving same functionality is still within the spirit and scope of the invention. 
         [0019]    Please refer to  FIG. 1 , which is a cross-sectional diagram schematically showing an inducing unit  300  according to the present invention. The inducing unit  300  comprises an inducing element  520 , a shielding element  380 , a counter electrode  390 , a color element CF, and a liquid crystal layer  305 . The inducing element  520  is disposed on a substrate  301 . The shielding element  380 , the color element CF, and the counter electrode  390  are disposed on a counter substrate  302  facing to the substrate  301 . There is a gap having a first spacing d 1  between the counter electrode  390  and the inducing element  520 . The structure of the inducing element  520  comprises a gate G, a gate-insulating layer  312 , a channel  315 , a high doping region  316 , a source S, a drain D, and a passivation layer  360 . The inducing element  520  can be a PMOS transistor, an NMOS transistor, a diode, or a thin film transistor. The channel  315  can be an amorphous-silicon semiconductor layer. The high doping region  316  can be an amorphous-silicon semiconductor region highly doped with N-type impurity. The shielding element  380  is a metal or non-metal layer having feature of light absorption or reflection. 
         [0020]    The conductivity of the channel  315  is increasing or decreasing in response to the gate voltage of the gate G and the counter voltage of the counter electrode  390 . Without any external force applied to the counter substrate  302 , the first spacing d 1  of the gap is unchanged. Therefore, the conductivity of the channel  315  is controlled only by the gate voltage of the gate G, and is almost not affected by the counter voltage of the counter electrode  390 . Meanwhile, a background signal can be generated based on the conductivity of the channel  315  before applying any external force to the counter substrate  302 . The shielding element  380  is utilized to prevent the channel  315  from being influenced by ambient light. The shielding element  380  is an optional element and is not a must. 
         [0021]    Please refer to  FIG. 2 , which is a cross-sectional diagram schematically showing the deformation of the counter substrate  302  of the inducing unit  300  in  FIG. 1  when applying an external force to the counter substrate  302 . The external force can be a pressing force applied by a finger or a touch pen in a touched position. As shown in  FIG. 2 , because of the external force, the spacing of the gap is reduced from the first spacing d 1  to a second spacing d 2 , and the influence of the counter voltage of the counter electrode  390  on the conductivity of the channel  315  is enhanced. In other words, the influence of the electric field produced by the counter voltage on the channel  315  is dependent on the spacing of the gap, and the electric field is a function of the counter voltage, the first spacing d 1 , and the second spacing d 2 . That is, when the spacing of the gap is reduced from the first spacing d 1  to a second spacing d 2 , the intensity of the electric field would be changed and affects the conductivity of the inducing element  520 . Accordingly, the inducing element  520  is able to generate an inducing signal corresponding to the conductivity of the channel  315  in response to the external force. As a result, by way of analyzing the inducing signal or comparing the inducing signal with the background signal, the touched position can be positioned. 
         [0022]    Please refer to  FIG. 3 , which is a circuit diagram schematically showing an array structure  500  according to the present invention. The array structure  500  comprises a plurality of gate lines  540 , a plurality of data lines  550 , a plurality of readout lines  560 , and a plurality of pixel areas Ra. Each of the plurality of pixel areas Ra is enclosed by adjacent gate lines  540  and adjacent data lines  550  correspondingly. Each of the plurality of pixel areas Ra comprises a switching element  510 , a storage capacitor Cst, a liquid crystal capacitor Clc, and a pixel electrode. 
         [0023]    Some of the plurality of pixel areas Ra further comprises an inducing element  520  and a readout element  530 . Each of the plurality of gate lines  540  is a conductive line used for conducting a gate voltage. The readout element  530  is a PMOS transistor, an NMOS transistor, a diode, or a thin film transistor. The inducing signal generated by the inducing element  520  can be transferred to the corresponding readout line  560  via the corresponding readout element  530 . The gate G of a switching element  510  and the source S of a corresponding inducing element  520  in the same pixel area Ra are electrically connected to different gate lines  540  respectively. 
         [0024]    When the gate of an inducing element  520  is furnished with a negative voltage so that the inducing element  520  is not selected to be active for inducing, the corresponding readout element  530  coupled to the inducing element  520  is utilized to filter noise generated from the inducing element  520 . For instance, an undesirable inducing signal caused by ambient light may come out from the inducing element  520 , and the undesirable inducing signal can be filtered by the readout element  530 . Both the readout element  530  and the readout line  560  are optional elements. That is, the data line  550  may be electrically connected to the inducing element  520  directly and function to act as a readout line. 
         [0025]    Please refer to  FIG. 4 , which is a layout diagram schematically showing a panel structure  700  according to the present invention. The panel structure  700  comprises a plurality of gate lines  540 , a plurality of common electrode lines  545 , a plurality of data lines  550 , a plurality of readout lines  560 , a plurality of pixel electrodes  570 , a plurality of switching elements  510 , a plurality of inducing elements  520 , and a plurality of readout elements  530  disposed on a substrate. The panel structure  700  further comprises a plurality of color elements CF disposed on a counter substrate. The plurality of color elements CF comprises a plurality of red elements  570   r , a plurality of green element  570   g , and a plurality of blue elements  570   b . The plurality of color elements CF may further comprise a plurality of white elements. The inducing elements  520  can be disposed on the pixel areas corresponding to individuals of the red elements  570   r , the green elements  570   g , the blue elements  570   b , the white elements, or the composite thereof. In a preferred embodiment, the inducing elements  520  are disposed on the pixel areas corresponding to the blue elements  570   b . The drain D of the switching element  510  is electrically connected to the corresponding pixel electrode  570  through a first via hole  511 . The source S of the inducing element  520  is electrically connected to the corresponding gate line  540  through a second via hole  521 . 
         [0026]    Please refer to  FIG. 5 , which is a schematic diagram showing a pixel unit according to the present invention. The area shielded by the shielding element  380  covers the inducing element  520 , the readout element  530 , and the switching element  510 . The blue element  570   b  disposed on the counter substrate is corresponding to the pixel electrode  570  disposed on the substrate. The structure of the inducing unit  300  shown in  FIG. 1  is the cross-sectional diagram taken along line  1 - 1 ′ in  FIG. 5 . 
         [0027]    Please refer to  FIG. 6 , which is a circuit diagram schematically showing an inducing circuit  900  according to the present invention. Please note that some elements of the circuit such as the data lines, common electrode lines, switching elements, and pixel electrodes are omitted in  FIG. 6  for the sake of demonstrating the inducing circuit  900  clearly. The inducing circuit  900  comprises a plurality of inducing elements  520 , a plurality of readout elements  530 , a plurality of gate lines  540 , a plurality of readout lines  560 , and a readout circuit  990 . 
         [0028]    The inducing element  520  and the readout element  530  are not necessary to be disposed for each of the plurality of gate lines  540 . That is, the inducing element  520  and the readout element  530  can be disposed to the gate lines separated by at least one gate line without the inducing element  520  and the readout element  530  disposed. The readout circuit  990  can be electrically connected to at least one readout line. For instance, the readout circuit  990  in  FIG. 6  is electrically connected to eight readout lines  560 , and the inducing signals furnished to the readout circuit  990  from the eight readout lines  560  can be converted to a readout signal Vout. The readout signal Vout is then analyzed or compared with the background signal for positioning the touched position. 
         [0029]    Please refer to  FIG. 7 , which is a circuit diagram schematically showing an array structure  585  according to the present invention. The gate G of a switching element  510  and the source S of a corresponding inducing element  520  in the same pixel area Ra are electrically connected to the same gate line  540 . The other circuit connections concerning the array structure  585  is the same as the circuit connections concerning the array structure  500  shown in  FIG. 3 , and for the sake of brevity, further discussion on the other circuit connections concerning the array structure  585  is omitted. 
         [0030]    Please refer to  FIG. 8 , which is a circuit diagram schematically showing an array structure  595  according to the present invention. The source S of the inducing element  520  is electrically connected to an independent voltage source  597  through a corresponding power line  596 . That is, the gate G and source S of the inducing element  520  in  FIG. 8  are driven by a signal voltage from the gate line  540  and a power voltage from the independent voltage source  597  respectively, which means that the inducing signal can be adjusted independently. 
         [0031]    Please refer to  FIG. 9 , which is a circuit diagram schematically showing an array structure  596  according to the present invention. The gate G of the inducing element  520  in  FIG. 9  is electrically connected to a selection line  542 . The selection lines  542  are conductive lines coupled to an independent power source, so as to provide selection signals for enabling the inducing element  542  being selected for inducing. 
         [0032]    Based on the aforementioned panel structure, a related positioning method is disclosed for a display device. The display device comprises a counter electrode, an inducing element, and a readout circuit. The positioning method comprises the following steps: 
         [0033]    Step S 10 : touch the display device in a position; 
         [0034]    Step S 20 : change a gap between the counter electrode and the inducing element for modulating a conductivity of the inducing element to a modulated conductivity of the inducing element corresponding to the position; 
         [0035]    Step S 30 : generate an inducing signal based on the modulated conductivity of the inducing element; 
         [0036]    Step S 40 : furnish the inducing signal to the readout circuit; and 
         [0037]    Step S 50 : analyze the inducing signal for positioning the touched position. 
         [0038]    The positioning method described above may comprise generating an electric field for affecting the inducing element based on a voltage of the counter electrode. The electric field is dependent on the voltage and the gap. That is, the conductivity of the inducing element corresponding to the touched position can be modulated in response to the intensity of the electric field dependent on the gap between the counter electrode and the inducing element in the touched position. 
         [0039]    The positioning method described above may further comprise the steps of providing a shielding element to shield the inducing element from ambient light, a readout element to filter noise generated from the inducing element, and generating a background signal based on the conductivity of the inducing element prior to touching the display device in the position. 
         [0040]    Accordingly, the step S 50  may comprise comparing the inducing signal with the background signal for positioning the touched position. Besides, the step S 40  may comprise furnishing the inducing signal to the readout circuit for converting the inducing signal into a readout signal, and the step S 50  may comprise analyzing the readout signal or comparing the readout signal with the background signal for positioning the touched position. 
         [0041]    Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention.