KR20060133330A - Method and apparatus for processing signals in liquid crystal display device comprising the unified touch screen - Google Patents

Abstract

An LCD(Liquid Crystal Display) embedded with a touch screen and a signal processing method thereof are provided to clearly discriminate a real touch signal and a noise signal by using the signal detected in the touch screen as a location detection signal after smoothening noises from the detected signal. A touch panel(810) detects a voltage change of a touch area. An ADC(Analog Digital Converter)(820) converts the signal output from the touch panel into a digital signal. A signal processor(830) removes the noises from the converted digital signal. A controller(850) detects a location of the touch area according to the voltage change of the noise-removed signal. The touch panel includes a sensor TFT(Thin Film Transistor) generating optical current according to reflected light of an object touching the LCD panel, a storage capacity charging electric charge according to the generated optical current, and a switch TFT outputting the voltage according to the charged electric charge.

Description

{Method and apparatus for processing signals in liquid crystal display device comprising the unified touch screen}

1 (a) is a schematic configuration diagram of a touch screen embedded in a liquid crystal display according to the prior art.

1B is a flowchart illustrating a touch screen operation of a liquid crystal display device having a touch screen according to the related art.

FIG. 2 is experimental data illustrating a signal change generated during a touch operation of a liquid crystal display having a touch screen according to the related art.

3A is a layout diagram of a thin film transistor substrate of a liquid crystal display device with a touch screen according to the present invention.

3B is a cross-sectional view taken along line AA ′ of the sensor pixel.

4 is a schematic configuration diagram of a touch screen embedded in a liquid crystal display according to the present invention.

5 is a diagram showing the effect of applying the median filter.

6 is a flowchart illustrating a touch screen operation embedded in the liquid crystal display according to the present invention.

7 is a flowchart illustrating a signal processing method of a touch screen embedded in a liquid crystal display according to the present invention.

FIG. 8 is experimental data illustrating a signal change generated when a touch operation of a liquid crystal display having a touch screen according to the present invention is performed.

* Description of the symbols for the main parts of the drawings *

300: unit pixel 312: R pixel

314: B pixels 316: B pixels

320: sensor pixel 370: sensor thin film transistor

380: storage capacitor 390: switch thin film transistor

810 touch panel 820 A / D converter

830: signal processor 840: memory

850: controller 860: interface

870: driver

The present invention relates to an integrated touch screen panel liquid crystal display device in which the touch screen panel is embedded in the liquid crystal display device, and more particularly, to make it possible to clearly distinguish the touch signal from the noise signal in the integrated touch screen liquid crystal display device. A method and apparatus for processing an output signal of a screen panel.

The touch screen generates a photocurrent according to the change of the light reflected by the contacting object, charges the generated charges, and outputs a voltage according to the charged charges to sense the position, and is generally a thin film form. It consists of and adheres on the board | substrate of a liquid crystal display panel.

On the contrary, the thin film transistor type optical sensor includes a sensor thin film transistor which generates a photocurrent according to the intensity of light incident from the outside, a storage capacitor storing the received charge amount as information, and an amount of charge stored in the storage capacitor according to an external control signal. It is composed of a switch thin film transistor for switching the information of the form, the manufacturing process of the array of the thin film transistor-type optical sensor is similar to the manufacturing process of the array of the thin film transistor liquid crystal display device, so when forming the thin film transistor substrate array of the liquid crystal display panel, A liquid crystal display device in which a thin film transistor type optical sensor is formed simultaneously and an optical sensor is formed inside a liquid crystal display panel has been proposed.

1 (a) is a schematic configuration diagram of a touch screen embedded in a liquid crystal display according to the prior art.

The touch screen embedded in the liquid crystal display of FIG. 1A includes a touch panel 10, an A / D converter 20, a controller 30, and a driver 50.

The touch panel 10 includes a thin film transistor type optical sensor of a liquid crystal display, and the thin film transistor type optical sensor includes a sensor thin film transistor which generates a photo current according to the intensity of light incident from the outside, as described above; A storage capacitor for storing the received charge amount as information, and a switch thin film transistor for switching the information in the form of charge amount stored in the storage capacitor in accordance with an external control signal.

The A / D converter 20 performs a function of converting a signal input from the touch panel 10 into a digital signal.

The controller 30 receives a signal from the A / D converter 20, detects a voltage change, and generates coordinates corresponding to the changed digital signal.

The generated coordinates are transmitted to the driver 50 through the interface 40, and the driver 50 receives these coordinates and operates a mouse pointer.

1B is a flowchart illustrating a touch screen operation of a liquid crystal display device having a touch screen according to the related art.

First, the touch panel of the touch screen is operated (S10).

The analog signal output from the touch panel is converted into a digital signal (S20).

It is determined whether there is a change in the voltage value of the digitally converted output signal (S30).

As a result of the determination, if there is a change in the voltage value, the coordinates of the position where the change in the voltage value has occurred are generated (S40).

After transmitting the generated coordinate values to the driver (S50), the mouse pointer is operated based on the transmitted coordinate values (S60).

FIG. 2 is experimental data illustrating a change in a signal generated during a touch operation of a liquid crystal display having a touch screen according to the related art.

Referring to FIG. 2, changes in voltage values for frames (times) in regions (a), (b), and (c) are shown.

In the signals (a), (b) and (c), the first voltage change appears in the A section (about 46 frames to about 57 frames), and the second voltage change occurs in the B section (about 63 frames to about 90 frames). Appears, a third voltage change appears in the C section (about 91 frames to about 101 frames), and a fourth voltage change appears in the D section (about 115 frames to about 120 frames).

However, only section A and section C are actual touch signals, and the remaining sections B and D are noise signals.

As described above, in the prior art, since the signal sensed by the touch panel is used as it is without undergoing a signal processing process, the signal cannot be clearly distinguished from the actual touch signal and the noise signal, and the signal is not stable due to a sudden environmental change. . As a result, due to frequent malfunction of the touch screen, there is a problem that the reliability of the liquid crystal display device with a touch screen is lowered.

The present invention is to overcome the above-described problems, the technical problem to be achieved by the present invention after the signal processing process to mitigate the noise in the signal detected on the touch screen, by using the position sensing signal, the actual touch signal The present invention provides a liquid crystal display device with a touch screen signal processing method and a touch screen, which can clearly distinguish the noise signal from the noise signal.

According to an aspect of the present invention for achieving the object of the present invention, as a signal processing method of the touch screen embedded in the liquid crystal display device, a signal output from the touch panel for detecting a voltage change of the contact area as a digital signal Converting; Removing noise from the digitally converted signal; And detecting the voltage change of the noise-free output signal and recognizing the touch area based on the detected voltage change.

In the converting into the digital signal, the signal output from the touch panel is divided into frames having a predetermined time interval.

The removing of the noise may include comparing output signal values of predetermined interval frames including an arbitrary frame and outputting an output signal value corresponding to an intermediate value among the output signal values of the predetermined interval frames in the arbitrary frame. And determining the signal value.

The predetermined time is characterized in that about 1/25 seconds to 1/30 seconds.

The number of the predetermined period frames is characterized in that 5 to 10.

According to another aspect of the present invention for achieving the object of the present invention, as a signal processing method of the touch screen embedded in the liquid crystal display device, a signal output from the touch panel for detecting a voltage change of the contact area for a predetermined time interval Dividing into a frame having; Comparing output signal values of predetermined interval frames including an arbitrary frame and determining an output signal value corresponding to an intermediate value among the output signal values of the predetermined interval frames as an output signal value in the arbitrary frame; Characterized in that it comprises a.

The predetermined time is characterized in that about 1/25 seconds to 1/30 seconds.

The number of the predetermined period frames is characterized in that 5 to 10.

According to another aspect of the present invention for achieving the object of the present invention, a liquid crystal display device with a built-in touch screen, a touch panel for detecting a voltage change of the contact area; An analog / digital converter for converting a signal output from the touch panel into a digital signal; And a controller for detecting a position of the contact area according to a voltage change of the signal from which the noise is removed and a signal processor for removing noise from the converted digital signal.

The touch panel may include a sensor thin film transistor configured to generate a photo current according to reflected light of an object in contact with the liquid crystal display panel; And a storage thin film transistor configured to output a voltage corresponding to a charge charged in the storage capacitor and a storage capacitor charging the charge according to the generated photocurrent.

The signal processor is characterized in that the median filter.

The apparatus may further include a memory for storing the signal output from the analog / digital converter.

The unit pixel of the liquid crystal display may include R, G, and B pixels for displaying an image on the liquid crystal display panel, and the touch panel.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the present invention.

3A is a layout diagram of a thin film transistor substrate of a liquid crystal display device with a touch screen according to the present invention.

The thin film transistor substrate includes a plurality of unit pixels 300, wherein the unit pixels are R, G, and B pixels 312, 314, and 316 for displaying an image on a liquid crystal display panel, and a position for sensing positions on the liquid crystal display panel. Sensor pixels 320.

Each of the R, G, and B pixels 312, 314, and 316 includes a liquid crystal cell thin film transistor and a pixel electrode for driving a liquid crystal.

The sensor pixel 320 is adjacent to the R, G, and B pixels, and is formed in an area defined by two adjacent data lines of the plurality of data lines, and the sensor pixel 320 is formed of an object contacting the liquid crystal display panel. A sensor thin film transistor 370 for generating a photo current according to reflected light, a storage capacitor 380 for charging a charge according to the generated photo current, and a switch thin film transistor 390 for outputting a voltage according to the charge charged in the storage capacitor. ).

On the other hand, R, G, B pixels and sensor pixels may be configured differently from the above embodiment.

3B is a cross-sectional view taken along line AA ′ of the sensor pixel.

A region on the substrate is defined as a sensor thin film transistor region 370, a storage capacitor region 380, and a switch thin film transistor region 390, and conductive metal is deposited on the substrate 400. The deposited conductive metal is patterned according to a predetermined pattern to form the sensor gate 372 on the substrate of the sensor thin film transistor region, and the switch gate 398 is formed on the substrate 400 of the switch thin film transistor region.

A first insulating film 500, such as a silicon oxide film SiO ₂ and a silicon nitride film SiNx, is formed over the entire surface on the substrate formed as described above. A semiconductor material is deposited on the first insulating film 500, and patterned according to a predetermined pattern to form a sensor active layer 378 on the first insulating film 500 of the sensor thin film transistor region. The switch active layers 396 are formed on the insulating film 500, respectively.

A conductive metal is deposited on the first insulating layer 500 on which the sensor and the switch active layer are formed, and patterned according to a predetermined pattern to form a sensor drain 374, a sensor source 376, a first storage electrode 381, and a switch drain. 392 and switch source 394 are formed, respectively.

Then, the second insulating film 385 is formed over the entire surface. A conductive metal is deposited on the second insulating film 385, and patterned according to a predetermined pattern to form a light blocking film 600 on the second insulating film 385 of the switch region. The second storage electrode 386 is formed on the second insulating layer 385 of the storage capacitor region.

In addition to the sensor pixels described above, sensor pixels having other structures may be used.

Referring to the operation of the touch screen having the above structure, when a user touches an object or a finger on the color filter substrate of the liquid crystal display panel, the light incident on the color filter substrate is reflected on the object or the finger, and the active layer of the sensor thin film transistor Is received by the sensor thin film transistor 370, the storage capacitor 380 charges a charge according to the amount of light input. The switch thin film transistor 390 reads the amount of charge charged in the storage capacitor 380 and outputs this signal.

4 is a schematic configuration diagram of a touch screen embedded in a liquid crystal display according to the present invention.

Referring to FIG. 4, the touch screen embedded in the liquid crystal display includes a touch panel 810, an A / D converter 820, a signal processor 830, a memory 840, a controller 850, and a driver 870. ).

As described above, the touch panel 810 includes sensor pixels formed on the thin film transistor substrate of the liquid crystal display. Such sensor pixels include sensor thin film transistors, storage capacitors, and switch thin film transistors.

When the user touches the touch panel, when light enters the active layer of the sensor thin film transistor, the sensor thin film transistor is turned on, the storage capacitor charges a charge according to the amount of light input, and the switch thin film transistor is a storage capacitor. The amount of charged charge is read and this signal is output.

The A / D converter 820 converts a signal input from the touch panel 810 into a digital signal.

The memory 840 receives and outputs a signal output from the A / D converter 820 as an input, and the signal processor 830 reads an output signal stored in the memory 840 to the touch panel. The noise signal included in the output signal of is eliminated.

The signal from which the noise is removed through the signal processor 830 is input to the controller 850, and the controller 850 generates coordinates corresponding to the changed digital signal.

The generated coordinates are transmitted to the driver 870 through the interface 860, and the driver 870 receives these coordinates and operates a mouse pointer.

Looking at the signal processor 830 in detail, the signal processor 830 is preferably a median filter using a median in a predetermined interval, and from the touch panel 810 using the median filter Signal processing the output signal.

In this way, when the intermediate filter is used, the noise signal can be removed to the extent that the touch signal and the noise signal can be distinguished.

5 is a diagram showing the effect of applying the median filter.

Referring to FIG. 5, data before applying the median filter and after applying the median filter are shown. As shown in FIG. 5, when the intermediate filter is applied, the impulse noise is reduced and the slope of the change amount of the rapidly changing signal is relaxed.

6 is a flowchart illustrating a touch screen operation embedded in the liquid crystal display according to the present invention.

Referring to FIG. 6, first, a touch panel is operated (S610).

A signal output from the touch panel, that is, an analog signal is converted into a digital signal (S620).

A process of removing noise from an output signal of the touch panel converted into a digital signal is performed (S630).

Through the step S630, it is determined whether there is a change in the predetermined voltage value from the signal from which the noise is removed (S640). In the present embodiment, the predetermined voltage value is set to about 20mV, this threshold may be set differently.

If the change in the predetermined voltage value occurs in step S640, the coordinate value of the position where the change in the voltage value occurs is generated (S650). On the contrary, if a change in the predetermined voltage value does not occur, the process returns to the step S610.

The coordinate value generated in step S650 is transmitted to the driver through an interface (S660).

Then, the mouse pointer is operated based on the coordinate values transmitted to the driver (S670).

7 is a flowchart illustrating a signal processing method of a touch screen embedded in a liquid crystal display according to the present invention.

Referring to FIG. 7, first, the touch panel is operated, and a signal is output in order to detect a voltage change from the touch panel (S710).

The signal output from the touch panel is divided into frames having a predetermined time interval, and a process of converting the signal into a digital signal is performed (S720).

In this embodiment, the predetermined time interval is set to about 1/25 seconds to 1/30 seconds. That is, the signal output from the touch panel for one second defines about 25 to 30 output signal values.

Thereafter, a process of comparing output signal values of predetermined interval frames including an arbitrary frame is performed (S730). In the present embodiment, the number of the predetermined period frames is set to 5 to 10, but is not limited thereto.

After the operation S730 is performed, an output signal value corresponding to an intermediate value among the output signal values of the predetermined period frames is determined as the output signal value in the arbitrary frame (S740).

As an example, a process of determining an output signal value in an arbitrary N-th frame will be described, assuming that the number of predetermined interval frames is five.

The output signal values of the N th frame to the N + 4 th frame are compared to determine an intermediate value as the output signal value of the N th frame. Then, in the same manner as above, the output signal values in the N + 1 th frame are compared with the output signal values of the N + 1 th frame to the N + 5 th frame, and the intermediate value of the N + 1 th frame is compared. It is determined by the output signal value. The output signal values of the following frames are also determined in the same manner as above.

On the other hand, to determine the output signal value in any N-th frame, by comparing the output signal values of the N-2 th frame to the N + 2 th frame, the intermediate value is determined as the output signal value of the N th frame It may be.

FIG. 8 is experimental data illustrating a signal change generated when a touch operation of a liquid crystal display having a touch screen according to the present invention is performed.

The experimental data shown in FIG. 8 is a result of processing the signal shown in FIG. 2 by the signal processing method according to the present invention.

In the signals (a), (b), and (c), a first voltage change occurs in the A section (about 51 frames to about 58 frames), and a second voltage change occurs in the B section (about 63 frames to about 90 frames). The third voltage change appears in section C (about 93 frames to about 103 frames), and the fourth voltage change appears in section D (about 116 frames to about 122 frames).

However, only the voltage change in the A and C sections is the actual touch signal, and the slight voltage change in the remaining B and D sections is the noise signal.

Compared with the experimental data of FIG. 2, the noise signals in the section B and the section D shown in FIG. 8 are very small compared to the touch signals in the section A and section C, and thus the touch signal and the noise are very small. The signal can be clearly distinguished.

What has been described above is only an exemplary embodiment of a liquid crystal display device with a touch screen and a signal processing method of a touch screen according to the present invention, and the present invention is not limited to the above-described embodiment, and the claims As claimed, any person having ordinary skill in the art without departing from the gist of the present invention will have the technical spirit of the present invention to the extent that various modifications can be made.

As described above, according to the present invention, after the signal processing process to mitigate the noise in the signal detected by the touch screen, by using the position detection signal, it is possible to clarify the distinction between the actual touch signal and the noise signal. As a result, the reliability of the position sensing operation of the liquid crystal display having the touch screen is further improved.

Claims (13)

In the signal processing method of the touch screen embedded in the liquid crystal display device, (a) converting a signal output from the touch panel for detecting a voltage change in the contact area into a digital signal; (b) removing noise from the digitally converted signal; (c) detecting a voltage change of the noise-free output signal; and and (d) recognizing the touch area based on the sensed voltage change. The method of claim 1, In the step (a), the signal processing method of the touch screen, characterized in that to divide the signal output from the touch panel into a frame having a predetermined time interval. The method of claim 2, In step (b), (b1) comparing output signal values of predetermined interval frames including any frame; and and (b2) determining an output signal value corresponding to an intermediate value among the output signal values of the predetermined section frames as an output signal value in the arbitrary frame. The method according to claim 2 or 3, The predetermined time is about 1/25 seconds to 1/30 seconds, the signal processing method of the touch screen. The method according to claim 2 or 3, The number of the predetermined section frame is a signal processing method of the touch screen, characterized in that 5 to 10. In the signal processing method of the touch screen embedded in the liquid crystal display device, (a) dividing a signal output from the touch panel for detecting a voltage change in the contact region into frames having a predetermined time interval; (b) comparing output signal values of predetermined interval frames including any frame; and and (c) determining an output signal value corresponding to an intermediate value among the output signal values of the predetermined section frames as an output signal value in the arbitrary frame. The method of claim 6, The predetermined time is about 1/25 seconds to 1/30 seconds, the signal processing method of the touch screen. The method of claim 6, The number of the predetermined section frame is a signal processing method of the touch screen, characterized in that 5 to 10. In the liquid crystal display device with a built-in touch screen, A touch panel for sensing a change in voltage of the contact area; An analog / digital converter for converting a signal output from the touch panel into a digital signal; A signal processor for removing noise from the converted digital signal; And a controller for sensing a position of the contact area according to a voltage change of the signal from which the noise is removed. The method of claim 9, The touch panel, A sensor thin film transistor configured to generate a photo current according to reflected light of an object in contact with the liquid crystal display panel; A storage capacitor charging a charge according to the generated photocurrent; And a switch thin film transistor configured to output a voltage according to a charge charged in the storage capacitor. The method of claim 9 or 10, And the signal processing unit is an intermediate value filter. The method of claim 11, And a memory for storing a signal output from the analog / digital converter. The method of claim 12, The unit pixel of the liquid crystal display device is composed of R, G, B pixels and the touch panel for displaying an image on the liquid crystal display panel.

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