KR20080054546A - Display device - Google Patents

Abstract

A display device is provided to set a new reference value whenever power is applied to determine whether the display device senses a touch even though an irregular sense signal is output according to a process condition and sensing environment. A display device includes a display panel(300), a plurality of sensing units(SU), a sense signal processor(800), and a touch determination unit(700). The display panel includes a plurality of pixels. The sensing units generate device output signals based on a touch applied to the display panel. The sense signal processor generates sense data based on the device output signals. The touch determination unit compares the sense data with a reference value to determine whether the display panel is touched. The reference value is set according to the sense data for a reference sensing unit among the plurality of sensing units.

Description

Display device {DISPLAY DEVICE}

1 is a block diagram of a liquid crystal display according to an exemplary embodiment of the present invention, which is a block diagram of a liquid crystal display including pixels.

2 is an equivalent circuit diagram of one pixel of a liquid crystal display according to an exemplary embodiment of the present invention.

3 is a block diagram of a liquid crystal display according to an exemplary embodiment of the present invention, which is a block diagram of a liquid crystal display including a sensing unit.

4 is an equivalent circuit diagram of a sensing unit of a liquid crystal display according to an exemplary embodiment of the present invention.

5 is a schematic diagram of a liquid crystal display according to an exemplary embodiment of the present invention.

6 is an equivalent circuit diagram of a plurality of sensing units connected to one sensing data line in a liquid crystal display according to an exemplary embodiment of the present invention.

7 is a schematic diagram illustrating an initial sensing area according to an embodiment of the present invention.

8 is a flowchart illustrating an operation of the contact determining unit illustrated in FIG. 3.

The present invention relates to a display device.

In recent years, with the reduction in weight and thickness of personal computers and televisions, display devices are also required to be lighter and thinner, and cathode ray tubes (CRTs) are being replaced by flat panel displays.

Such flat panel displays include liquid crystal displays (LCDs), field emission displays (FEDs), organic light emitting displays, plasma display panels (PDPs), and the like. There is this.

In general, in an active matrix flat panel display, a plurality of pixels are arranged in a matrix form, and an image is displayed by controlling the light intensity of each pixel according to given luminance information. Among them, the liquid crystal display includes two display panels including a pixel electrode and a common electrode, and a liquid crystal layer having dielectric anisotropy interposed therebetween. The liquid crystal display device applies an electric field to the liquid crystal layer, and adjusts the intensity of the electric field to adjust the transmittance of light passing through the liquid crystal layer to obtain a desired image.

A touch screen panel is a device that touches a finger or a touch pen (stylus) on the screen to write and draw letters or pictures, or execute icons to perform a desired command on a machine such as a computer. . A liquid crystal display with a touch screen panel may find out whether a user's finger or a touch pen touches the screen and contact position information. However, such a liquid crystal display has problems such as a cost increase due to a touch screen panel, a decrease in yield due to a process of attaching the touch screen panel to a liquid crystal panel, a decrease in luminance of the liquid crystal panel, and an increase in product thickness.

Therefore, in order to solve these problems, a technology for embedding a sensing element in a liquid crystal display device instead of a touch screen panel has been developed. The sensing element detects a change in light or pressure applied to a screen by a user's finger or the like so that the liquid crystal display may determine whether the user's finger or the like has touched the screen and contact position information.

The sensing elements are arranged in a row direction and a column direction, and when a contact occurs, a sensing element at a corresponding position outputs a signal. This signal is compared with the stored reference value to read the contact status and the contact position.

However, if the reference value is fixed to a constant value, the contact information cannot be read accurately because it cannot cope with both the process deviation and the user's operating environment.

Accordingly, an aspect of the present invention is to provide a liquid crystal display including a signal reading algorithm capable of responding to environmental changes.

According to an aspect of the present invention, there is provided a display device including a display panel including a plurality of pixels, a plurality of sensing units configured to generate an element output signal based on contact with the display panel, and based on the element output signal. A detection signal processor configured to generate sensed data, and a touch determiner configured to compare a reference value with the sensed data to determine whether the touched signal is detected, wherein the reference value is determined according to the sensed data of the reference detector, among the plurality of detectors. Is set.

The reference value may be reset whenever power is input to the display device.

The reference value may have a value of a product of the sensing data and a sensing constant of the reference detecting unit.

The sensing constant defines sensing information and noise information and may have a value less than one.

The reference sensing unit may be disposed in a central area of the display panel.

The plurality of detection units may include a plurality of the reference detection units, and the reference detection units may be disposed at a predetermined distance.

The touch determination unit may compare the representative value and the reference value among the plurality of sensing data with each other.

The representative value may be the largest value of the plurality of sensing data.

The sensing unit may include a variable capacitor having a liquid crystal as a dielectric material, the capacitance of which changes according to pressure, and a reference capacitor connected in series with the variable capacitor.

DETAILED DESCRIPTION Embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention.

In the drawings, the thickness of layers, films, panels, regions, etc., are exaggerated for clarity. Like parts are designated by like reference numerals throughout the specification. When a part of a layer, film, region, plate, etc. is said to be "on" another part, this includes not only the other part being "right over" but also another part in the middle. On the contrary, when a part is "just above" another part, there is no other part in the middle.

A liquid crystal display, which is an embodiment of a display device according to the present invention, will now be described in detail with reference to FIGS. 1 to 6.

1 is a block diagram of a liquid crystal display according to an embodiment of the present invention, which is a block diagram of a liquid crystal display including pixels, and FIG. 2 is an equivalent of one pixel of the liquid crystal display according to an embodiment of the present invention. 3 is a block diagram of a liquid crystal display according to an exemplary embodiment of the present invention, which is a block diagram of a liquid crystal display including a sensing unit, and FIG. 4 is a block diagram of a liquid crystal display according to an exemplary embodiment of the present invention. 5 is a schematic diagram of a liquid crystal display according to an exemplary embodiment of the present invention, and FIG. 6 is a plurality of sensing connected to one sensing data line in a liquid crystal display according to an exemplary embodiment of the present invention. Negative equivalent circuit diagram.

1 and 3, a liquid crystal display according to an exemplary embodiment of the present invention includes a liquid crystal panel assembly 300, a gate driver 400, a data driver 500, and a sensing signal connected thereto. The processor 800 includes a gray voltage generator 550 connected to the data driver 500, a contact determiner 700 connected to the sensing signal processor 800, and a signal controller 600 for controlling the gray level voltage generator 550.

1 and 3, the liquid crystal panel assembly 300 includes a plurality of display signal lines G ₁ -G _n , D ₁ -D _m and a plurality of pixels PX connected thereto and arranged in a substantially matrix form. ). Liquid crystal panel assembly 300 is also a plurality of sense lines _{(SY 1 -SY N, SX 1} -SX M, RL) and is connected thereto, and a plurality are arranged in the form of a substantially matrix sensor (SU), detection signal line ( _{SY 1 -SY N, SX 1 -SX} M) a plurality of the reset signal input (INI at one end connected to each), the sense signal line _{(SY 1 -SY N, SX 1} -SX M) detect a plurality of each connected to the other end of the And a plurality of output data lines OY _1- OY _N and OX ₁ -OX _M respectively connected to the signal output unit SOUT and the sense signal output unit SOUT.

2 and 4, the liquid crystal panel assembly 300 includes a thin film transistor array panel 100 and a common electrode panel 200 facing each other, a liquid crystal layer 3 interposed therebetween, and two display panels. Spacer (not shown) which forms a gap between 100 and 200 and which is deformed to some extent is included.

The display signal lines G ₁ -G _n and D ₁ -D _m include a plurality of gate lines G ₁ -G _n transmitting gate signals and data lines D ₁ -D _m transferring data signals. . Detection signal _{(SY 1 -SY N, SX 1} -SX M, RL) includes a plurality of line sensing data lines for transmitting the detected data signal (SY ₁ -SY _N) and a plurality of thermal data line (SX ₁ -SX _M And a plurality of reference voltage lines RL for transmitting the reference voltage. The reference voltage swings the high level and the low level at regular intervals, and the reference voltage line RL may be omitted.

The gate lines G ₁ -G _n and the row sensing data lines SY ₁ -SY _N extend substantially in the row direction and are substantially parallel to each other, and the data lines D ₁ -D _m and the column sensing data lines SX. ₁ -SX _M ) extends approximately in the column direction and is nearly parallel to each other.

As shown in Fig. 2, each pixel PX, for example, the i-th (i = 1, 2, ..., n) gate line G _i and the j-th (j = 1, 2,... m) The pixel PX connected to the data line D _j includes a switching element Q connected to the signal lines G _i and D _j , a liquid crystal capacitor Clc, and a storage capacitor connected thereto. capacitor) (Cst). Holding capacitor Cst can be omitted as needed.

The switching element Q is a three-terminal element such as a thin film transistor provided in the thin film transistor array panel 100, the control terminal of which is connected to the gate lines G ₁ -G _n , and the input terminal of the data line D ₁ -D _m ), and the output terminal is connected to the liquid crystal capacitor Clc and the storage capacitor Cst. In this case, the thin film transistor includes amorphous silicon or poly crystalline silicon.

The liquid crystal capacitor Clc has two terminals, the pixel electrode 191 of the thin film transistor array panel 100 and the common electrode 270 of the common electrode display panel 200, and the liquid crystal layer 3 between the two electrodes 191 and 270. Functions as a dielectric. The pixel electrode 191 is connected to the switching element Q, and the common electrode 270 is formed on the entire surface of the common electrode display panel 200 and receives the common voltage Vcom. Unlike in FIG. 2, the common electrode 270 may be provided in the thin film transistor array panel 100. In this case, at least one of the two electrodes 191 and 270 may be linear or rod-shaped.

The storage capacitor Cst, which serves as an auxiliary role of the liquid crystal capacitor Clc, is formed by overlapping a separate signal line (not shown) and the pixel electrode 191 provided in the thin film transistor array panel 100 with an insulator interposed therebetween. A predetermined voltage such as the common voltage Vcom is applied to this separate signal line. However, the storage capacitor Cst may be formed such that the pixel electrode 191 overlaps the front gate line directly above the insulator.

On the other hand, in order to implement color display, each pixel PX uniquely displays one of the primary colors (spatial division) or each pixel PX alternately displays the primary colors over time (time division). The desired color is recognized by the spatial and temporal sum of these primary colors. Examples of the primary colors include three primary colors such as red, green, and blue. FIG. 2 illustrates that each pixel PX includes a color filter 230 representing one of the primary colors in an area of the common electrode display panel 200 corresponding to the pixel electrode 191 as an example of spatial division. . Unlike FIG. 2, the color filter 230 may be formed above or below the pixel electrode 191 of the thin film transistor array panel 100.

At least one polarizer (not shown) for polarizing light is attached to an outer surface of the liquid crystal panel assembly 300.

As shown in FIG. 4, each of the sensing units SU has a variable capacitor Cv and a sensing data line SL connected to a row or column sensing data line (hereinafter referred to as sensing data line) indicated by reference numeral SL. And a reference capacitor Cp connected between and the reference voltage line RL.

The reference capacitor Cp is formed by overlapping the reference voltage line RL and the sensing data line SL of the thin film transistor array panel 100 with an insulator (not shown) interposed therebetween.

The variable capacitor Cv has the sensing data line SL of the thin film transistor array panel 100 and the common electrode 270 of the common electrode display panel 200 as two terminals, and the liquid crystal layer 3 between the two terminals functions as a dielectric. do. The capacitance of the variable capacitor Cv is changed by an external stimulus such as a user's touch applied to the liquid crystal panel assembly 300. For example, pressure may be used as the external stimulus. When pressure is applied to the common electrode display panel 200, the spacer is compressed and deformed so that the distance between the two terminals is changed to change the capacitance of the variable capacitor Cv. When the capacitance changes, the magnitude of the contact voltage Vn between the reference capacitor Cp and the variable capacitor Cv changes, which depends on the magnitude of the capacitance. The contact voltage Vn flows through the sensing data line SL as a sensing data signal, and based on the contact voltage Vn, the contact voltage Vn may be determined.

The sensing unit SU is disposed between two adjacent pixels PX. The density of the row and column sense data line _{(SY 1 -SY N, SX 1} -SX M) of a pair of sensing unit (SU) which is connected, respectively, disposed adjacent to the region in which they cross in, for example, It may be about one quarter of the dot density. Here, one dot includes three pixels PX arranged side by side and displaying three primary colors such as red, green, and blue, and displays one color, and a basic unit representing the resolution of the liquid crystal display device is shown. do. However, one dot may consist of four or more pixels PX, and in this case, each pixel PX may display one of three primary colors and white.

An example in which the density of the pair of sensing units SU is 1/4 of the dot density is when the row and column resolutions of the pair of sensing units SU are 1/2 of the row and column resolution of the liquid crystal display device, respectively. Can be. In this case, there may be a pixel row and a pixel column without the sensing unit SU.

By matching the detection unit SU density and the dot density to such an extent, the liquid crystal display device may be applied to high precision applications such as character recognition. Of course, the resolution of the sensing unit SU may be higher or lower as necessary.

As described above, according to the sensing unit SU according to the exemplary embodiment of the present invention, since the space occupied by the sensing unit SU and the sensing data line SL is relatively small, the reduction of the aperture ratio of the pixel PX can be minimized.

Referring to FIG. 6, all of the reset signal input units INI have the same structure, and each includes a reset transistor Qr. The reset transistor Qr is a three-terminal element of the thin film transistor, the control terminal of which is connected to the reset control signal RST, the input terminal of the reset voltage Vr, respectively, and the output terminal of the sensing data line. (SL) (Fig. 3 SX ₁ -SX _M, or SY ₁ -SY _N) is connected to the. The reset transistor Qr is positioned in the edge region P2 of the liquid crystal panel assembly 300 in which no pixel is disposed and supplies the reset voltage Vr to the sensing data line SL according to the reset control signal RST. .

In addition, the plurality of sensing signal output units SOUT also have the same structure, and each includes an output transistor Qs. The output transistor Qs is also a three-terminal element of the thin film transistor whose control terminal is connected to the sensing data line SL, its input terminal is connected to the input voltage Vs, and the output terminal is the output data line OL. ) The output transistor Qs is also positioned in the edge region P2 of the liquid crystal panel assembly 300 and generates an output signal based on the sensing data signal flowing through the sensing data line SL. An output current is mentioned as an output signal. Alternatively, the output transistor Qs may generate a voltage as an output signal.

The reset transistor Qr and the output transistor Qs, which are thin film transistors, are formed together with the switching element Q.

The output data lines OY ₁ -OY _N and OX ₁ -OX _M are connected to the row and column sense data lines SY ₁ -SY _N and SX ₁ -SX _M , respectively, through the corresponding sense signal output SOUT. a plurality of row and column output data line which comprises _{(OY 1 -OY N, OX 1} -OX M). The output data lines OY ₁ -OY _N and OX ₁ -OX _M are connected to the sensing signal processing unit 800 and transmit an output signal from the sensing signal output unit SOUT to the sensing signal processing unit 800. The row and column output data lines OY ₁ -OY _N and OX ₁ -OX _M extend approximately in the column direction and are substantially parallel to each other.

Referring back to FIGS. 1 and 3, the gray voltage generator 550 generates two sets of gray voltage sets (or reference gray voltage sets) related to the transmittance of the pixel. One of the two sets has a positive value for the common voltage Vcom and the other set has a negative value.

The gate driver 400 is connected to the gate lines G ₁ -G _n of the liquid crystal panel assembly 300 to gate-on voltage Von for turning on the switching element Q, and gate-off voltage Voff for turning off the gate element 400. A gate signal consisting of a combination of the signals is applied to the gate lines G ₁ -G _n .

The data driver 500 is connected to the data lines D ₁ -D _m of the liquid crystal panel assembly 300, and selects a gray voltage from the gray voltage generator 550 and uses the data line D ₁ as a data signal. -D _m ). However, when the gray voltage generator 550 provides only a predetermined number of reference gray voltages instead of providing all of the voltages for all grays, the data driver 500 divides the reference gray voltages and thus the gray voltages for all grays. Generate and select the data signal from it.

The sensing signal processor 800 includes a plurality of amplifiers 810 connected to the output data lines OY _1- OY _N and OX _1- OX _M of the liquid crystal panel assembly 300.

As illustrated in FIG. 6, the plurality of amplifiers 810 all have the same structure, and each amplifier 810 includes an amplifier AP, a capacitor Cf, and a switch SW. The amplifier AP has an inverting terminal (-), a non-inverting terminal (+) and an output terminal, the inverting terminal (-) is connected to the output data line OL, and between the inverting terminal (-) and the output terminal The capacitor Cf and the switch SW are connected, and the non-inverting terminal + is connected to the reference voltage Va. The amplifier AP and the capacitor Cf generate an amplified output signal Vo by integrating the output current from the output transistor Qs for a predetermined time as a current integrator.

Therefore, the sense signal processor 800 converts the analog amplified output signal Vo from the amplifier 810 into a digital signal using an analog-to-digital converter (not shown) or the like, and processes the signal to process the digital sense data signal ( DSN).

The touch determining unit 700 receives the digital sensing data signal DSN from the sensing signal processing unit 800, performs a predetermined calculation process, determines whether or not the contact is made, and sends the contact information INF to an external device. The touch determination unit 700 may monitor an operation state of the sensing unit SU based on the digital sensing data signal DSN and control signals applied thereto. The contact determination unit 700 will be described in more detail later.

The signal controller 600 controls operations of the gate driver 400, the data driver 500, the gray voltage generator 550, and the sensing signal processor 800.

Each of the driving devices 400, 500, 550, 600, 700, and 800 may be mounted directly on the liquid crystal panel assembly 300 in the form of at least one integrated circuit chip, or may be a flexible printed circuit film ( It may be mounted on the liquid crystal panel assembly 300 in the form of a tape carrier package (TCP) or mounted on a separate printed circuit board (not shown). In contrast, these drive units 400, 500, 550, 600, 700, 800 are connected to signal lines G ₁ -G _n , D ₁ -D _m , SY ₁ -SY _N , SX ₁ -SX _M , OY _1- OY _N , OX ₁ -OX _M , RL) and the thin film transistor Q may be integrated in the liquid crystal panel assembly 300.

Referring to FIG. 5, the liquid crystal panel assembly 300 is divided into a display area P1, an edge area P2, and an exposure area P3. In the display area P1, the pixel PX, the sensing unit SU, and the signal lines G ₁ -G _n , D ₁ -D _m , SY ₁ -SY _N , SX ₁ -SX _M , OY ₁ -OY _N , OX Most of _1- OX _M , RL) are located. The common electrode panel 200 includes a light blocking member (not shown) such as a black matrix, and the light blocking member covers most of the edge region P2 to block light from the outside. Since the common electrode panel 200 is smaller than the thin film transistor array panel 100, a portion of the thin film transistor array panel 100 is exposed to form an exposed area P3, and the integrated chip 610 is mounted on the exposed area P3. A flexible printed circuit board 620 is attached.

The integrated chip 610 is a driving device for driving a liquid crystal display, that is, an image driver 400, a data driver 500, a gray voltage generator 550, a signal controller 600, and a contact determiner 700. And a detection signal processor 800. By integrating the driving devices 400, 500, 550, 600, 700, and 800 into the integrated chip 610, the mounting area may be reduced, and power consumption may also be reduced. Of course, if necessary, at least one of them or at least one circuit element constituting them may be outside the integrated chip 610.

The signal lines G ₁ -G _n , D ₁ -D _m and the sensing data lines SY ₁ -SY _N , SX ₁ -SX _M extend to the exposure area P3 to correspond to the corresponding driving devices 400, 500, and 800. ).

The FPC board 620 receives a signal from an external device and transmits the signal to the integrated chip 610 or the liquid crystal panel assembly 300, and the end is usually formed of a connector (not shown) to facilitate connection with the external device. .

Next, the display operation and the detection operation of the liquid crystal display will be described in detail.

The signal controller 600 receives input image signals R, G, and B and an input control signal for controlling the display thereof from an external graphic controller (not shown). The input image signals R, G, and B contain luminance information of each pixel PX, and the luminance is a predetermined number, for example, 1024 (= 2 ¹⁰ ), 256 (= 2 ⁸ ), or 64 (= 2 ⁶ ) It has gray. Examples of the input control signal include a vertical sync signal Vsync, a horizontal sync signal Hsync, a main clock signal MCLK, and a data enable signal DE.

The signal controller 600 properly processes the input image signals R, G, and B according to operating conditions of the liquid crystal panel assembly 300 based on the input image signals R, G, and B and the input control signal, and controls the gate. After generating the signal CONT1 and the data control signal CONT2, the gate control signal CONT1 is sent to the gate driver 400, and the data control signal CONT2 and the processed image signal DAT are transmitted to the data driver 500. Export to).

The gate control signal CONT1 includes a scan start signal STV indicating a scan start and at least one clock signal controlling an output period of the gate-on voltage Von. The gate control signal CONT1 may also further include an output enable signal OE that defines the duration of the gate-on voltage Von.

The data control signal CONT2 applies an analog data voltage to the horizontal synchronizing start signal STH and the data lines D ₁ -D _m indicating the start of transmission of the digital image signal DAT for one row of pixels PX. Includes a load signal LOAD and a data clock signal HCLK. The data control signal CONT2 also inverts the signal RVS which inverts the polarity of the data voltage with respect to the common voltage Vcom (hereinafter referred to as "polarity of the data voltage" by reducing the "polarity of the data voltage with respect to the common voltage"). It may further include.

According to the data control signal CONT2 from the signal controller 600, the data driver 500 receives the digital image signal DAT for the pixel PX in one row and corresponds to each digital image signal DAT. By selecting the gray scale voltage, the digital image signal DAT is converted into an analog data voltage and then applied to the corresponding data lines D ₁ -D _m .

The gate driver 400 applies the gate-on voltage Von to the gate lines G ₁ -G _n in response to the gate control signal CONT1 from the signal controller 600, thereby applying the gate lines G ₁ -G _n . Turn on the switching element (Q) connected to. Then, the data voltage applied to the data lines D ₁ -D _m is applied to the pixel PX through the turned-on switching element Q.

The difference between the data voltage applied to the pixel PX and the common voltage Vcom is shown as the charging voltage of the liquid crystal capacitor Clc, that is, the pixel voltage. The arrangement of the liquid crystal molecules varies according to the magnitude of the pixel voltage, thereby changing the polarization of light passing through the liquid crystal layer 3. This change in polarization is represented by a change in the transmittance of light by the polarizer, through which the pixel PX displays the luminance represented by the gray level of the image signal DAT.

This process is repeated in units of one horizontal period (also referred to as "1H" and equal to one period of the horizontal sync signal Hsync and the data enable signal DE), thereby all the gate lines G ₁ -G _n. ), The gate-on voltage Von is sequentially applied, and the data voltage is applied to all the pixels PX to display an image of one frame.

When one frame ends, the state of the inversion signal RVS applied to the data driver 500 is controlled so that the next frame starts and the polarity of the data voltage applied to each pixel PX is opposite to the polarity of the previous frame. "Invert frame"). At this time, even in one frame, the polarity of the data voltage flowing through one data line is periodically changed according to the characteristics of the inversion signal RVS (eg, row inversion and point inversion) or polarity of the data voltage applied to one pixel row. They can be different (eg invert columns, invert points).

Meanwhile, the sensing signal processor 800 reads an output signal from the output sensing line OL with a predetermined period. The read signal is amplified again through the current-voltage amplifier AP, converted into a digital sense data signal DSN, and transmitted to the signal controller 600. The signal controller 600 performs a touch recognition operation to find out whether a contact is made and a contact position by appropriately calculating and processing a signal from the detection signal processor 800, and transmits the information about this to an external device or the like. The external device transmits an image signal based on this information to the liquid crystal display device. Alternatively, the digital sensing data signal DSN may be directly transmitted to the external device so that the external device directly performs a touch recognition operation.

The sensing signal processing unit 800 is applied through the output data lines OY _1- OY _N and OX _1- OX _M in the porch section between the frames once every frame according to the sensing data control signal CONT3. It is preferable to read the output signal and to perform a sensing operation in the front porch section of the vertical synchronization signal Vsync. In the porch section, since the sensing data signal is less influenced by driving signals from the gate driver 400 and the data driver 500, the reliability of the sensing data signal is increased. However, such a read operation is not necessarily performed every frame, but may be performed once every plurality of frames as necessary. In addition, the read operation may be performed more than once in the porch section, and the read operation may be performed at least once even in a frame outside the porch section.

Hereinafter, referring to FIG. 6, a read operation of the sense data signal will be described in detail.

The common voltage Vcom has a high level and a low level and swings the high level and the low level every 1H.

The reset control signal RST has a turn on voltage for turning on the reset transistor Qr and a turn off voltage for turning off the reset transistor Qr. The turn-on voltage may use the gate-on voltage Von, the turn-off voltage may use the gate-off voltage Voff, and other voltages may be used. The turn-on voltage of the reset control signal RST is applied when the common voltage Vcom is at a high level.

When the turn-on voltage is applied to the reset transistor Qr, the reset transistor Qr is turned on to apply the reset voltage Vr applied to the input terminal to the sensing data line SL to sense the data line as the reset voltage Vr. Initialize (SL). On the other hand, when the operation is started and the reference voltage Va is applied to the amplifier 810, the capacitor Cf of the amplifier 810 is charged to the reference voltage Va, so that the output voltage of the amplifier AP ( The magnitude of Vo is equal to the reference voltage Va.

When the reset control signal RST becomes the turn-off voltage Toff, the sensing data line SL is in a floating state, and the change in the capacitance of the variable capacitor Cv and the common voltage according to whether the sensing unit SU is in contact with each other. The voltage applied to the control terminal of the output transistor Qs changes based on the variation in Vcom. According to the voltage change, the current of the sensing data signal flowing through the output transistor Qs varies.

On the other hand, after the reset signal RST is changed to the gate-off voltage Voff, the switching signal Vsw is applied to the switch SW to discharge the voltage charged in the capacitor Cf.

Then, when a predetermined time elapses, the sensing signal processor 800 reads the amplified output signal Vo. In this case, the time for reading the amplified output signal Vo is preferably set within 1H after the reset control signal RST becomes the turn-off voltage Voff. In other words, it is preferable to read the amplified output signal Vo before the common voltage Vcom becomes high again. This is because the amplified output signal Vo also changes as the level of the common voltage Vcom changes.

Since the sensing data signal is changed based on the reset voltage Vr, the sensing data signal may always have a predetermined range of voltage levels, thereby easily determining whether or not the contact is made.

The turn-on voltage of the reset control signal RST may be applied when the common voltage Vcom is at a low level. At this time, the amplification output signal Vo is read before the common voltage Vcom is changed to a high level and again becomes low. . In addition, the reset control signal RST may be synchronized with the gate signal applied to the last gate line G _n .

As described above, after the analog sense data signal is read using each amplifier 810, the sense signal processor 800 converts the amplified output signal Vo into a digital sense data signal DSN to determine the contact determination unit 700. Export to). The digital sensing data signal DSN contains information corresponding to the difference between the amplified output signal Vo in the previous sensing operation and the amplified output signal Vo in the current sensing operation.

The touch determination unit 700 receives a digital sensing data signal DSN, performs appropriate arithmetic processing to find out whether a contact is made and a contact position, and transmits the same to an external device, and the external device receives image signals R, G, and B based thereon. Is transmitted to the liquid crystal display to display the screen or menu selected by the user or the like.

Hereinafter, with reference to FIGS. 7 and 8, a contact determination unit 700 that can accurately read contact information according to process conditions and environmental changes will be described.

FIG. 7 is a schematic diagram illustrating an initial sensing area according to an exemplary embodiment of the present invention, and FIG. 8 is a flowchart illustrating an operation of the contact determining unit illustrated in FIG. 3.

Referring to FIG. 7, the liquid crystal display according to the exemplary embodiment of the present invention includes an arbitrary initial sensing region 310.

The initial sensing region 310 includes a plurality of sensing units SU, and may be set at the center Xx and Yy of the liquid crystal panel assembly 300 as shown in FIG. The sensing area 310 may be located.

Referring to FIG. 8, when power is supplied to the liquid crystal display to start an operation, the touch determination unit 700 reads the digital sensing data signal DSN from the initial sensing region 310.

The touch determination unit 700 calculates a reference value DSNth using the digital sensing data signal DSN of the initial sensing region 310.

In this case, the reference value DSNth may be calculated by multiplying the digital sensing data signal DSN of the initial sensing region 310 by the reference constant, and the reference constant is whether the digital sensing data signal DSN is due to contact or noise. It is a criterion to distinguish whether or not according to the value, and has a value less than one. In this case, the reference value DSNth may be calculated for each row and column detector SU, and each reference value DSNth for the row and column detectors may be calculated by different reference constants.

The touch determination unit 700 converts and stores the reference value DSNth stored before the power is supplied to the newly calculated reference value DSNth.

When the new reference value DSNth is set as described above, the touch determination unit 700 receives the plurality of digital sensing data signals DSN during the next sensing operation, and thus the row digital sensing data signal DSN and the column digital sensing data signal. Classify as (DSN).

The touch determination unit 700 selects a representative value DSNmax for each classified digital sensing data signal DSN, and in this case, the representative value DSNmax may be a digital sensing data signal DSN having the largest value. Next, the representative value DSNmax and the reference value DSNth of the row and column digital sense data signals are compared, respectively.

When the representative value DSNmax of the digital sensing data signal is larger than each reference value DSNth, the touch determination unit 700 determines that a contact has occurred, and the contact occurs and the contact position to the outside through an interface (not shown). Print information.

Meanwhile, when the representative value DSNmax of the digital sensing data signal is smaller than each reference value DSNth, the touch determination unit 700 receives the digital sensing data signal DSN of the next sensing operation and performs classification.

By setting a new reference value DSNth each time the power is input, whether or not an irregular sensing signal is output depending on the process condition and sensing environment can be flexibly read.

In the exemplary embodiment of the present invention, the sensing unit using the variable capacitor and the reference capacitor as the sensing unit is exemplified, but the present invention is not limited thereto, and other types of sensing elements may be applied. That is, the common electrode of the common electrode display panel and the sensing data line of the thin film transistor array panel have two terminals. At least one of the two terminals protrudes, so that the two terminals are physically and electrically connected by the user's contact to sense the common voltage. A pressure sensor output as a data signal or an optical sensor whose output signal changes in accordance with light intensity may be used. In addition, the present invention can be applied to a display device including two or more sensing units.

In addition, in the exemplary embodiment of the present invention, the liquid crystal display device is described as a display device, but the present invention is not limited thereto, and the same applies to a flat panel display device such as a plasma display device and an organic light emitting display device. Can be applied.

As described above, according to the present invention, by setting a new reference value every time the power is input, whether or not an irregular sensing signal is output depending on the process condition and the sensing environment can be read flexibly.

Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

Claims (9)

A display panel including a plurality of pixels, A plurality of detectors generating an element output signal based on a contact with the display panel; A sensing signal processor configured to generate sensing data based on the device output signal; A contact determination unit determining whether a contact is made by comparing a reference value with the sensed data Including; The reference value is set according to the sensing data of the reference sensing unit of the plurality of sensing units. Display device. In claim 1, And the reference value is reset each time power is input to the display device. In claim 2, And the reference value has a value of a product of the sensing data and a sensing constant of the reference detecting unit. In claim 3, The sensing constant defines sensing information and noise information and has a value less than one. In claim 4, And the reference sensing unit is disposed in a central area of the display panel. In claim 4, The plurality of detection unit includes a plurality of the reference detection unit, And the reference sensing unit is disposed at a predetermined distance. In claim 5 or 6, And the touch determination unit compares a representative value of the plurality of sensing data with the reference value. In claim 7, And the representative value is the largest value of the plurality of sensing data. In claim 1, The sensing unit A variable capacitor having a liquid crystal as a dielectric and whose capacitance changes with pressure, and A reference capacitor connected in series with the variable capacitor Containing Display device.

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