JP2008165436A - Touch panel device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce costs, and to improve the precision in detecting a touch position by integrating a liquid crystal panel and a touch panel. <P>SOLUTION: This touch panel device is provided with: a color filter substrate having a CF side common electrode 14; an array substrate having a pixel electrode; a liquid crystal installed between the color filter substrate and the array substrate; and a gate driver 2 and a gate driver 3 for driving the liquid crystal. This touch panel device is provided with a signal processing circuit 5 for measuring a current value flowing through the CF side common electrode 14 at four corners when a contact object contacts a panel surface; and a control circuit 6 for calculating the position coordinates of the contact position of the contact based on the value of the measured current. The signal processing circuit 5 measures the current value during a blanking period when the gate driver 2 and the gate driver 3 are not driven. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a touch panel device, and more particularly to a touch panel device using a configuration of a liquid crystal display.

  2. Description of the Related Art Conventionally, touch panels have been developed that output an electric current signal corresponding to an input position on an image surface by touching the input position with a contact object such as a finger (for example, see Patent Document 1).

  In this conventional capacitive touch panel, a second transparent substrate for preventing glare is bonded to the touch surface side of the first transparent substrate provided with a transparent conductive film for touch position detection by a transparent adhesive. Thus, the transparent conductive film can be reliably prevented from being damaged, and the structure is simplified and the mechanical strength is improved.

  However, in the structure of such a capacitive touch panel, the touch panel itself must be adhered to the front surface of the display, so that there is a problem that the thickness of the device itself increases or the cost is high. .

  Therefore, in order to solve these problems, a touch panel device that can reduce the thickness and cost of the device itself has been proposed by sharing the electrode plate of the display and the touch panel (see, for example, Patent Document 2). ).

  FIG. 8 is a diagram showing a configuration of a conventional touch panel device described in Patent Document 2. As shown in FIG. As shown in FIG. 8 (a), the conventional touch panel device displays a character or an image by sequentially laminating a common transparent electrode 109, a liquid crystal 110, and a display transparent electrode 111 between two transparent insulating plates 107 and 108. In addition, in order to detect the position coordinates of the contact portion on the transparent insulating plate 107 disposed on the side of the common transparent electrode 109 with which a contact object such as a finger comes into contact, as shown in FIG. At the four corners, current detectors 101 to 104 for detecting a current flowing between the contact object and the common transparent electrode 109 via the transparent insulating plate 107 are attached, and the contact object contacts the contact portion on the transparent insulating plate 107. A signal processing circuit 106 is provided for calculating the position coordinates of the contact portion based on the current signals S1 to S4 from the current detectors 101 to 104 at the four corners affected by the change in capacitance due to the above.

JP-A-5-324203 JP 2003-99192 A

  However, the configuration of the conventional touch panel device shown in Patent Document 2 has a problem in that an error occurs in the detection of the touch position and the input may be erroneously recognized. The reason will be described below. FIG. 9 is a diagram showing the waveform timing of dot inversion driving. In FIG. 9, Vcom is a common voltage, Vgh is a gate ON voltage, Vgl is a gate OFF voltage, and Vsig is a data voltage. Thus, the common voltage Vcom is essentially constant, does not fluctuate, and there is almost no current flowing in and out. However, this is theoretical, and as shown in FIG. 10, the common voltage Vcom fluctuates due to the coupling of the signal line and the gate line, and current always flows in and out. For this reason, even if current measurement for touch position detection is performed in this state, an error occurs and the touch position cannot be detected with high accuracy.

  The present invention has been made to solve such problems, and by integrating a liquid crystal panel and a touch panel, it is possible to obtain a touch panel device that reduces costs and improves the accuracy of position detection of a touch position. It is aimed.

  The present invention includes a color filter substrate having a common electrode, an array substrate having a pixel electrode, a liquid crystal provided between the color filter substrate and the array substrate, and a driving means for driving the liquid crystal. A touch panel device provided with a current measuring means for measuring a current value flowing through the common electrode at one or more locations when a contact object comes in contact with the panel surface, and a magnitude of the measured current value. And a position coordinate calculation means for calculating a position coordinate of the contact position of the contact object, and the current measurement means measures the current value during a blanking period when the drive means is not driven. The common electrode is wired in a substantially rectangular shape, and the current measuring means is a touch panel device that measures the current value at four corners of the common electrode.

  The present invention includes a color filter substrate having a common electrode, an array substrate having a pixel electrode, a liquid crystal provided between the color filter substrate and the array substrate, and a driving means for driving the liquid crystal. A touch panel device provided with a current measuring means for measuring a current value flowing through the common electrode at one or more locations when a contact object comes in contact with the panel surface, and a magnitude of the measured current value. And a position coordinate calculation means for calculating a position coordinate of the contact position of the contact object, and the current measurement means measures the current value during a blanking period when the drive means is not driven. The common electrode is wired in a substantially rectangular shape, and the current measuring means is a touch panel device that measures the current value at the four corners of the common electrode. By integrating the liquid crystal panel and the touch panel, it is possible to improve the accuracy of the position detection of the touch position with reduce cost.

  FIG. 1 is a diagram showing a basic configuration of a touch panel device according to the present invention. As shown in FIG. 1, the touch panel device includes a liquid crystal panel 1 having a pixel matrix, a gate driver 2 that is a driving circuit for driving the gate lines GL of the liquid crystal panel 1, and a data line DL of the liquid crystal panel 1. A data driver 3 which is a driving circuit for driving, and a timing controller 4 for controlling the gate driver 2 and the data driver 3 are provided. In addition, when a contact object such as a finger or a touch pen comes into contact with the touch surface (display area) of the liquid crystal panel 1, the capacitance is changed by the capacitive touch panel device. If so, since the resistance value changes, the signal processing circuit 5 that calculates the position coordinates of the touch position of the contact object based on the change of the current value based on the resistance value, and the contents corresponding to the position coordinates are stored in the internal memory or the like A control circuit 6 is provided for extracting characters from the storage device 7 and displaying characters and images on the liquid crystal panel 1 based on the extracted data, or outputting signals to other devices by performing necessary processing.

  The liquid crystal panel 1 includes a pixel matrix composed of liquid crystal cells formed in each pixel region defined by the intersection of the gate line GL and the data line DL. The liquid crystal cell includes a liquid crystal cell Clc that adjusts a light transmission amount according to an image data signal and a thin film transistor TFT that is a liquid crystal driving switching element for driving the liquid crystal capacitor Clc. The thin film transistor TFT responds to the scan signal of the gate line GL so that the data signal of the data line DL is charged and maintained in the liquid crystal cell Clc. The liquid crystal cell Clc realizes gradation by changing the alignment state of the liquid crystal according to the data signal and adjusting the light transmittance. The gate driver 2 sequentially supplies scan signals to the gate lines GL in response to control signals from the timing controller 4. The data driver 3 converts the digital image data from the timing controller 4 into an analog data signal and supplies it to the data line DL. The timing controller 4 supplies control signals for controlling the gate driver 2 and the data driver 3 and also supplies digital image data to the data driver 3. As a result, the designated character or image is displayed in the display area of the liquid crystal panel 1.

  Next, the liquid crystal panel 1 will be described. As shown in the exploded perspective view of FIG. 2, the liquid crystal panel 1 is composed of a color filter substrate 10 and an array substrate 20 that are bonded via a liquid crystal 9.

  The color filter substrate 10 is configured by sequentially forming a black matrix 12, a color filter 13, and a CF side common electrode 14 on a CF side glass substrate 11 made of a transparent insulating plate. The black matrix 12 is formed in a matrix on the CF side glass substrate 11. Such a black matrix 12 divides the region of the CF side glass substrate 11 into a plurality of cell regions where the color filter 13 is formed, and prevents light interference between adjacent cells and reflection of external light. The color filter 13 is formed in the cell region divided by the black matrix 12 and divided into red (R), green (G), and blue (B), and transmits red, green, and blue light, respectively. The CF-side common electrode 14 applies a common voltage (Vcom) that serves as a reference when driving the liquid crystal 9 to the transparent conductive layer coated on the entire surface of the color filter 13. In addition, an overcoat layer (not shown) may be further formed between the color filter 13 and the CF side common electrode 14 in order to flatten the color filter 13.

  The array substrate 20 is defined by a plurality of gate lines GL and data lines DL that run vertically and horizontally on the array-side glass substrate 21 made of a transparent insulating plate, and intersections of the gate lines GL and the data lines DL. A thin film transistor TFT and an array pixel electrode 22 formed for each cell region are provided. The thin film transistor TFT supplies a data signal from the data line DL to the array pixel electrode 22 in accordance with a gate signal from the gate line GL. The array pixel electrode 22 made of a transparent conductive layer is supplied with a data signal from the thin film transistor TFT and drives the liquid crystal 9.

  The liquid crystal 9 having dielectric anisotropy rotates according to the electric field formed by the data signal of the array pixel electrode 22 and the common voltage (Vcom) of the common electrode 14, and realizes gradation by adjusting the light transmittance. . The liquid crystal panel 1 further includes an alignment film for initial alignment of the liquid crystal 9 and a spacer (not shown) for maintaining a constant cell gap between the color filter substrate 10 and the array substrate 20.

  The basic configuration of the liquid crystal panel 1 has been described above. The touch panel device according to the present invention is configured using the liquid crystal panel 1 described above, displays characters and images on the liquid crystal panel 1, and displays the display area of the liquid crystal panel 1. In this configuration, the position coordinates of the touch position (contact portion) on the color filter substrate 10 arranged on the CF side common electrode side with which a contact object such as a finger or a touch pen comes into contact is detected.

  FIG. 3 is a diagram showing an example of a panel configuration of a touch panel device using the liquid crystal panel 1 described above. 4 is a cross-sectional view taken along the line A-A ′ of FIG. 3. In the panel configurations shown in these drawings, the liquid crystal panel 1 includes a display area 30 composed of a pixel matrix and a black matrix frame portion 31 having a width 31 a provided around the display area 30. In addition, an X tab 32 for electrically connecting the data driver 3 and the liquid crystal panel 1 is provided on the liquid crystal panel 1. The X tab 32 is provided with a data line input unit 33 to which a data signal from the data line DL is input. Further, the liquid crystal panel 1 is provided with a Y tab 34 for electrically connecting the gate driver 2 and the liquid crystal panel 1. The Y tab 34 is provided with a gate line input unit 35 to which a gate signal from the gate line GL is input. In addition, a common electrode input unit 36 for applying a common voltage (Vcom) from the power source 8 (FIG. 1) to the CF side common electrode 14 is provided in three of the four corners of the CF side common electrode 14 wired in a substantially rectangular shape. It is provided in the corner. In addition, junctions 37 for electrically connecting the array-side common electrode 23 and the CF-side common electrode 14 are provided at the three corners (see the cross-sectional view of FIG. 4).

  As described above, in the configuration of FIG. 3, the X tab 32 and the Y tab 34 are respectively provided on the array substrate for the one tab. Therefore, the common voltage Vcom is often supplied to the CF side common electrode 14 at three points from the three common electrode input portions 36 as shown in FIG. In the case of using three or more points, the supply may be made from the side where the X tab 32 and the Y tab 34 are connected. In addition, as shown in FIG. 3, it has the structure which does not apply a voltage from the corner part of the lower right of drawing. Here, the term “one tab” refers to a case where the signal input is on one side. For example, when the signal input on the Y side is both, it is referred to as both tabs.

  FIG. 5 is a diagram showing another example of the panel configuration of the touch panel device using the liquid crystal panel 1 described above. The difference between FIG. 3 and FIG. 5 is that, in FIG. 5, a fourth joint portion 37A for electrically connecting the array-side common electrode 23 and the CF-side common electrode 14 to the lower right corner of the drawing. And a fourth common electrode input portion 36A for supplying a common voltage Vcom to the CF side common electrode 14 via the junction portion 37A is added to the upper right corner of the drawing. These are two points. Other configurations are the same as those in FIG. 3, and thus the description thereof is omitted here.

  FIG. 6 is a schematic explanatory diagram showing an array wiring configuration on the array substrate 20 in a portion surrounded by a dotted line B in FIG. As shown in FIG. 6, the common electrode input part 36 is connected to the joint part 37. Further, the common electrode input part 36A is formed by extending the common electrode input part 36A to form a lead line 36B by an array wiring, and is connected to the joint part 37A via the lead line 36B. The common electrode input part 36A and the lead line 36B may be formed integrally or separately.

  As described above, in the configuration of FIG. 5, the common electrode input portions 36 and 36A for supplying the common voltage Vcom to the CF side common electrode 14 are provided at the three corners of the liquid crystal panel 1 and one of them. Since the common electrode input part 36A is extended and connected to the joint part 37A provided at the fourth corner, a voltage can be supplied to the CF side common electrode 14 from the four corners. Thereby, a voltage can be independently applied to the four CF common electrodes 14 by independent array wiring.

  The operation of the touch panel device of the present invention configured as described above will be described. FIG. 7 is an explanatory diagram showing drive timing in the column direction in the touch panel device of the present invention. The liquid crystal panel 1 shown in FIGS. 3 and 5 is normally driven at 60 Hz. For example, taking VGA (Video Graphics Array) as an example, the number of pixels of VGA is 640 × 3 columns in the row direction and 480 rows in the column direction. If the timing of FIG. 7 is explained by VGA, the active period is 480 lines and the blanking period is several tens of lines. The active period is a period in which the data line DL and the gate line GL are driven and characters and images are displayed in the display area 30 of the liquid crystal panel 1, and the blanking period is also the data line DL. This is a period during which the gate line GL is not driven. The active period and the blanking period are determined by specifications (specifications) depending on the product, and are slightly different for each product. Since neither the data line DL nor the gate line GL is driven during the blanking period, the voltage is constant, and the common voltage Vcom is also constant without being affected by the coupling of the data line DL and the gate line GL.

  Therefore, in the touch panel device of the present invention, paying attention to this point, the position of the touch position is measured during the blanking period, the accuracy of current detection for position detection is improved, and the accuracy of position detection is increased.

  As a current measurement method, the CF side common electrode 14 (or the joint portions 37 and 37A between the CF side common electrode 14 and the array side common electrode 23) is used as a touch panel position detection sensor (current measurement means). In the capacitive type of the touch panel, electricity flows through the CF side common electrode 14 when a contact object such as a finger or a touch pen touches the panel surface, so that the current is measured at the joints 37 and 37A at the four corners of the liquid crystal panel 1. And output to the signal processing circuit 5. Since the magnitudes of the four current values are proportional to the distance to the touch position, the signal processing circuit 5 calculates the position coordinates of the touch position from the magnitudes of the four current values. . Based on the position coordinates of the calculated touch position, the control circuit 6 extracts processing contents preset for each display screen in correspondence with the position coordinates from the storage device 7, and based on the extracted processing contents, characters and images are extracted. The result is displayed on the display panel 1 or the result obtained by performing necessary processing is output to another device. In the configuration of FIG. 3, since the joint portions 37 are provided only at the three corners, the current values that can be measured are three, but the magnitudes of these three current values are respectively the same. Since it is proportional to the distance to the touch position, the signal processing circuit 5 can calculate the position coordinates of the touch position from the magnitudes of these three current values. However, accuracy is further improved by performing position detection using four current values.

  As described above, in the touch panel device of the present invention, the CF side common electrode provided on the liquid crystal panel is used as a current measuring means for detecting the touch position, so the electrode plate of the liquid crystal display and the touch panel is shared. The thickness of the device itself and the manufacturing cost can be reduced.

  Further, in the touch panel device of the present invention, the current measurement for position detection is performed during the blanking period in which the common voltage Vcom is constant, so that the influence of the coupling of the data line DL and the gate line GL is affected. Therefore, the accuracy of current detection for position detection can be improved, thereby improving the accuracy of position detection.

  Further, in the touch panel device of the present invention, as shown in FIG. 5, voltage application and current detection to the CF side common electrode 14 can be performed at the four corners of the liquid crystal panel 1, so that the current values detected at the four corners. Since the position of the touch position can be detected based on the size of the position, the accuracy of position detection can be improved.

  Further, in the touch panel device of the present invention, as shown in FIG. 5, the X tab 32 and the Y tab 34 are provided on the two sides of the liquid crystal panel 1, so that the corner portions of the sides where the tabs are not provided are provided. Since the lead wires 36B extending from either the X tab 32 or the Y tab 34 are provided by the array wiring so that current can be detected, independent current detection can be performed at the four corners. The accuracy of position detection can be improved by the improvement.

It is explanatory drawing which showed the basic composition of the touchscreen apparatus which concerns on this invention. It is the disassembled perspective view which showed the structure of the liquid crystal panel used for the touchscreen apparatus which concerns on this invention. It is the top view which showed an example of the panel structure of the touchscreen apparatus which concerns on this invention. FIG. 4 is a cross-sectional view taken along the line A-A ′ of FIG. 3. It is the top view which showed the other example of the panel structure of the touchscreen apparatus which concerns on this invention. It is explanatory drawing which showed the wiring structure of the dotted-line B part of FIG. It is explanatory drawing which showed operation | movement of the touchscreen apparatus which concerns on this invention. It is explanatory drawing which showed the structure of the conventional touchscreen apparatus. It is explanatory drawing which showed the theoretical waveform of the dot inversion drive. It is explanatory drawing which showed the actual waveform of the dot inversion drive.

Explanation of symbols

  1 liquid crystal panel, 2 gate driver, 3 data driver, 4 timing controller, 5 signal processing circuit, 6 control circuit, 7 storage device, 8 power supply, 9 liquid crystal, 10 color filter substrate, 11 CF side glass substrate, 12 black matrix, 13 color filter, 14 CF side common electrode, 20 array substrate, 21 array side glass substrate, 22 array pixel electrode, 23 array side common electrode, 30 display area, 31 black matrix frame, 31a width, 32 X tab, 33 data Line input part, 34 Y tab, 35 Gate line input part, 36, 36A Common electrode input part, 37, 37A Junction part, DL data line, GL gate line, TFT thin film transistor.

Claims (2)

A touch panel device comprising a color filter substrate having a common electrode, an array substrate having a pixel electrode, a liquid crystal provided between the color filter substrate and the array substrate, and a driving means for driving the liquid crystal Because
A current measuring means for measuring a current value flowing through the common electrode at one or more locations when a contact object contacts the panel surface;
Position coordinate calculation means for calculating the position coordinates of the contact position of the contact object based on the measured magnitude of the current value,
The current measuring means measures the current value during a blanking period when the driving means is not driven,
The common electrode is wired in a substantially rectangular shape,
The current measuring unit measures the current value at four corners of the common electrode. The touch panel device. Tabs to which signals from the driving means are input are provided on two adjacent sides of the panel,
In order to measure the current value by the current measuring means at the corner portion constituted by the two sides where the tab is not provided, the array wiring extended from the side where the tab is provided to the corner portion The touch panel device according to claim 1, wherein a lead wire is provided, and the current value is measured at a joint portion between the lead wire and the common electrode.

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