KR101172225B1 - Display device and input device - Google Patents

Abstract

A display device is disclosed. The display device includes a gate wiring; A data line crossing the gate line and defining a pixel area together with the gate line; A first thin film transistor driven by a first driving signal applied through the gate wiring and having a first threshold voltage; And a second thin film transistor driven by a second driving signal applied through the gate wiring and having a second threshold voltage lower than the first threshold voltage.

Touch, sensor, TIP, threshold, voltage, transistor

Description

DISPLAY DEVICE AND INPUT DEVICE}

Embodiments relate to a display device and an input device.

BACKGROUND With the development and popularization of graphical user interface (GUI) systems, the use of touchscreens with simple inputs has become commonplace.

In addition, with the development of information processing technology, display devices such as LCD, PDP and AMOLED are widely used. In particular, an optical touch integrated LCD including an optical sensor in an LCD panel is used.

Embodiments provide a display device and an input device capable of efficiently sensing a signal such as a touch input from the outside.

In an exemplary embodiment, a display device includes a gate wiring; A data line crossing the gate line and defining a pixel area together with the gate line; A first thin film transistor driven by a first driving signal applied through the gate wiring and having a first threshold voltage; And a second thin film transistor driven by a second driving signal applied through the gate wiring and having a second threshold voltage lower than the first threshold voltage.

In an exemplary embodiment, a display device may include: a plurality of gate lines arranged side by side; A plurality of data lines crossing the gate lines; First thin film transistors driven by a first driving signal applied through the respective gate lines and having a first threshold voltage; A plurality of pixel electrodes connected to the first thin film transistors, respectively; Second thin film transistors driven by a second driving signal applied through the respective gate wires and having a second threshold voltage lower than the first threshold voltage; And sensor units connected to the second thin film transistors, respectively.

An input device according to one embodiment includes a gate wiring; A data line crossing the gate line and defining the gate line and a pixel area; A pixel electrode disposed in the pixel area; A first thin film transistor driven by a first driving signal applied through the gate line, selectively connecting the data line and the pixel electrode, and having a first threshold voltage; A sensor unit disposed in the pixel area and configured to sense external light; And a second thin film transistor connected to the sensor unit and driven by a second driving signal applied through the gate wiring, and having a second threshold voltage lower than the first threshold voltage.

The display device and the input device according to the embodiment include a first thin film transistor and a second thin film transistor having different threshold voltages. Accordingly, the first thin film transistor and the second thin film transistor may be driven separately.

Since the second thin film transistor has a lower threshold voltage, only the second thin film transistor can be driven separately. That is, the second thin film transistor may be driven by a driving signal that is higher than the second threshold voltage and lower than the first threshold voltage. In this case, the first thin film transistor may not be driven.

In this case, a pixel electrode is connected to the first thin film transistor, and a sensor unit for sensing an external signal is connected to the second thin film transistor.

Accordingly, the sensing signal generated by sensing the external signal by the sensor unit may be output by the second thin film transistor without affecting the operation of the first thin film transistor.

That is, the second driving signal may be applied to the second thin film transistor when desired, regardless of the process of displaying an image. Accordingly, the sensing signal may be output when desired regardless of the process of displaying the image.

For example, only the first driving signal may be applied to the gate wiring during the display period, and only the second driving signal may be applied to the gate wiring during the porch.

Accordingly, the input device and the display device according to the embodiment can sense an external signal during the porch in which the pixel data is not input, and can process the sensing signal by excluding noise that may occur during the display period.

In addition, since the second thin film transistor has a low threshold voltage, the second thin film transistor may operate quickly and a second driving signal may be applied to the second thin film transistor at a high frequency.

Accordingly, the display device and the input device according to the embodiment can sense a signal input from the outside such as a touch for a very short time.

In addition, since the display device and the input device according to the embodiment can drive only the second thin film transistor, a signal can be received from the outside even when the pixel electrode is not driven.

In this case, the display device and the input device according to the embodiment do not need to continuously drive the pixel electrode, thereby reducing power consumption.

In addition, since the display device and the input device according to the embodiment can sample the sensing signal when desired, the overload of the signal processing unit can be reduced. Accordingly, the display device and the input device according to the embodiment can calculate the position of the touch using a complex algorithm.

In the description of the embodiments, each substrate, element, member, panel, electrode, pattern, or layer is placed on or under the "on" of each substrate, element, member, panel, electrode, pattern, or layer. And " under " include both " directly " or " indirectly " through other components. . In addition, the upper or lower reference of each component is described with reference to the drawings. The size of each component in the drawings may be exaggerated for the sake of explanation and does not mean the size actually applied.

1 is a circuit diagram illustrating a liquid crystal display according to an embodiment. 2 is a circuit diagram illustrating one pixel. 3 is a cross-sectional view illustrating the first thin film transistor. 4 is a cross-sectional view illustrating a second thin film transistor. 5 is a diagram illustrating a process of operating a liquid crystal display according to an exemplary embodiment. 6 and 7 illustrate a process in which the first driving signal and the second driving signal are applied to the gate lines. 8 is a diagram illustrating a process in which a first driving signal and a second driving signal are applied to gate lines in another manner.

1 and 2, the liquid crystal display according to the embodiment includes a liquid crystal panel 10, a driver 20, and a signal processor 30.

The liquid crystal panel 10 includes a plurality of gate lines 100, a plurality of data lines 200, a plurality of first thin film transistors 300, a plurality of second thin film transistors 400, and a plurality of pixels. The electrodes 500 include a plurality of sensor units 600 and a plurality of lead-out wires (RO) 700.

In addition, although not shown in the drawing, the liquid crystal panel 10 may be composed of two substrates facing each other and a liquid crystal layer interposed between the two substrates. In this case, the gate wires 100, the data wires 200, the first and second thin film transistors 300 and 400, the pixel electrodes 500, and the sensor units 600 are formed in the two lines. It may be included in one of the substrates.

The gate lines 100 extend in parallel in one direction. The gate lines 100 may be disposed in parallel to each other.

The data lines 200 extend in a direction crossing the gate lines 100. The data lines 200 extend in parallel with each other. The data lines 200 may cross substantially perpendicularly to the gate lines 100. The data lines 200 may be disposed in parallel to each other.

The pixel regions P are defined by the gate lines 100 and the data lines 200. For example, since the gate lines 100 and the data lines 200 vertically cross each other, the pixel areas P may have a rectangular planar shape.

The first thin film transistors 300 are disposed in regions where the gate lines 100 and the data lines 200 cross each other. In addition, the first thin film transistors 300 may be disposed in the pixel regions P, respectively.

As illustrated in FIG. 2, the first thin film transistor 300 is connected to the data line 200 and the pixel electrode 500, respectively. In more detail, the first thin film transistor 300 is driven by the first driving signals GS11, GS12... Which are applied through the gate wiring 100.

In this case, the first thin film transistor 300 selectively connects the data line 200 and the pixel electrode 500. That is, when the first driving signals GS11, GS12... Are applied to turn on the first thin film transistor 300 through the gate line 100, the first thin film transistor 300 is applied by the first thin film transistor 300. The data line 200 and the pixel electrode 500 are connected to each other.

As illustrated in FIGS. 1 and 2, the second thin film transistors 400 are connected to the sensor units 600, respectively. The second thin film transistors 400 are not disposed in all the pixel regions P, but are disposed in each of the pixel regions P.

In addition, the second thin film transistors 400 may be disposed in an area where the gate lines 100 and the lead-out lines 700 cross each other.

The second thin film transistors 400 are driven by the second driving signals GS21, GS22... Which are applied through the gate line 100.

In this case, the second thin film transistor 400 selectively connects the sensor unit 600 and the lead-out wiring 700. That is, when the second driving signals GS21, GS22... Are applied to turn on the second thin film transistor 400 through the gate wiring 100, the second thin film transistor 400 is applied to the second thin film transistor 400. As a result, the sensor unit 600 and the lead-out wiring 700 are connected to each other.

The first thin film transistor 300 has a first threshold voltage, and the second thin film transistor 400 has a second threshold voltage lower than the first threshold voltage.

Here, the threshold voltage is a gate that forms a conducting channel between a source and a drain in a field-effect-transistor (FET) and applies a voltage to the source and the drain to allow a current to flow in proportion thereto. The minimum voltage applied to

Accordingly, the first thin film transistor 300 may be operated by a high voltage driving signal, and the second thin film transistor 400 may be operated by a low voltage driving signal.

In this case, the first driving signals GS11, GS12... Are higher than the first threshold voltage and have a voltage. In addition, the second driving signals GS21, GS22... May have a voltage lower than the first threshold voltage and higher than the second threshold voltage.

Referring to FIG. 3, the first thin film transistor 300 includes a first gate electrode 310, a first channel region 330, a first source electrode 340, and a first drain electrode 350.

The first gate electrode 310 is disposed on the transparent substrate 11. The first gate electrode 310 is connected to the gate wiring 100. That is, the first gate electrode 310 may extend from the gate wiring 100.

A gate insulating layer 12 is disposed on the first gate electrode 310. The gate insulating layer 12 covers the first gate electrode 310.

The first channel region 330 is disposed corresponding to the first gate electrode 310. The first channel region 330 is disposed on the gate insulating layer 12.

The first source electrode 340 is disposed on the gate insulating layer 12. The first source electrode 340 is disposed on a portion of the first channel region 330. The first source electrode 340 is connected to the first channel region 330.

In addition, the first source electrode 340 is connected to the data line 200. For example, the first source electrode 340 may extend from the data line 200.

The first drain electrode 350 is disposed on the gate insulating layer 12. The first drain electrode 350 is disposed on another portion of the first channel region 330. The first drain electrode 350 is spaced apart from the first source electrode 340 and is connected to the first channel region 330.

In addition, the first drain electrode 350 is connected to the pixel electrode 500.

The first source electrode 340 and the first drain electrode 350 are covered by the passivation layer 13.

Referring to FIG. 4, the second thin film transistor 400 includes a second gate electrode 410, a second channel region 430, a second source electrode 440, and a second drain electrode 450.

The second gate electrode 410 is disposed on the transparent substrate 11. The second gate electrode 410 is connected to the gate wiring 100. That is, the second gate electrode 410 may extend from the gate wiring 100.

Similarly, the gate insulating layer 12 covers the second gate electrode 410.

The second channel region 430 is disposed corresponding to the second gate electrode 410. The second channel region 430 is disposed on the gate insulating layer 12.

The second source electrode 440 is disposed on the gate insulating layer 12. The second source electrode 440 is disposed on a portion of the second channel region 430. The second source electrode 440 is connected to the second channel region 430.

In addition, the second source electrode 440 is connected to the sensor unit 600.

The second drain electrode 450 is disposed on the gate insulating layer 12. The second drain electrode 450 is disposed on another portion of the second channel region 430. The second drain electrode 450 is spaced apart from the second source electrode 440 and is connected to the second channel region 430.

In addition, the second drain electrode 450 is connected to the lead-out wiring 700.

Similarly, the passivation layer 13 covers the second source electrode 440 and the second drain electrode 450.

The first channel region 330 may include conductive impurities at a lower concentration than the second channel region 430. That is, the first channel region 330 may not be doped with conductive impurities or may be doped at a very low concentration. At this time, the second channel region 430 is doped with a conductive impurity at a low concentration. That is, the second channel region 430 is doped with a conductive impurity at a higher concentration than the first channel region 330.

Accordingly, when a relatively high voltage is applied to the first gate electrode 310, an inversion layer is formed in the first channel region 330, and current may flow through the first channel region 330. have.

In addition, even when a relatively low voltage is applied to the second gate electrode 410, an inversion layer may be formed in the second channel region 430, and a current may flow through the second channel region 430.

Accordingly, the threshold voltages of the first thin film transistor 300 and the second thin film transistor 400 may vary due to the difference in the concentration of impurities doped in the first channel region 330 and the second channel region 430. This is different.

The pixel electrodes 500 are disposed in the pixel regions P, respectively. In more detail, the pixel electrodes 500 may be disposed in the pixel areas P, respectively.

The pixel electrodes 500 receive data signals applied through the data lines 200. The pixel electrodes 500 form an electric field with the common electrode by the data signal. Optical characteristics of the liquid crystal are changed by an electric field formed between the pixel electrodes 500 and the common electrode.

The pixel electrode 500 is connected to the first thin film transistor 300. The pixel electrode 500 may be made of a transparent conductor.

In addition, the liquid crystal panel 10 includes a first storage capacitor Cst1 connected to the pixel electrode 500. The first storage capacitor Cst1 maintains pixel data input to the pixel electrode 500 for a predetermined time.

The sensor units 600 are disposed in the pixel areas P. As illustrated in FIG. In more detail, the sensor units 600 may be disposed one by one in some of the pixel areas P. FIG.

The sensor units 600 generate a sensing signal by sensing a signal such as a touch input from the outside. For example, the sensor units 600 may generate an electrical sensing signal by sensing light input from the outside. For example, the sensor units 600 may include a photodiode or a photo TFT for sensing light.

As illustrated in FIG. 2, the sensor unit 600 includes a photo TFT 610, a driving voltage line Vdd 620, a second storage capacitor Cst2, and a third storage capacitor Cst3.

The photo TFT 610 senses light input from the outside. That is, the photo TFT 610 adjusts the intensity of the current passing through the photo TFT 610 according to the intensity of light input from the outside. That is, the intensity of the current flowing between the source and the drain of the photo TFT 610 varies according to the intensity of light input to the outside.

That is, a difference in the light leakage current generated by the photo TFT 610 occurs according to the intensity of light irradiated onto the photo TFT 610.

The driving voltage line 620 supplies a driving voltage to the photo TFT 610. The driving voltage line 620 is connected to the source of the photo TFT 610.

The second storage capacitor Cst2 temporarily stores the charge generated by the photoTFT 610.

The third storage capacitor Cst3 is connected to the pixel electrode 500 and stores charges for driving the photo TFT 610. The third storage capacitor Cst3 is connected to the gate of the photo TFT 610 to supply the charge to the gate of the photo TFT 610 as a driving voltage.

The lead-out wires 700 are connected to the second thin film transistors 400. The lead-out wires 700 may be disposed in parallel with the data wires 200.

In addition, the readout wires 700 are connected to the signal processor, and according to an operation of the second thin film transistor 400, charges stored in the second storage capacitor Cst2, that is, the sensor unit 600. The sensing signal generated by) is transferred to the signal processor 30.

The driver 20 applies a signal for driving the liquid crystal panel 10 through the gate lines 100 and the data lines 200. That is, the driver 20 drives the liquid crystal panel 10.

The driver 20 includes a gate driver 21 and a data driver 22.

The gate driver 21 is connected to the gate lines 100. The gate driver 21 generates the first driving signals GS11, GS12... And the second driving signals GS21, GS22.

The gate driver 21 transmits the first driving signals GS11, GS12... And the second driving signals GS21, GS22... Through the gate lines 100 to the first thin film transistor. To the gates 300 and the second thin film transistors 400.

The data driver 22 is connected to the data wires 200. The data driver 22 generates pixel data for displaying an image. The data driver 22 applies the pixel data to the pixel electrodes 500 through the data lines 200.

The signal processor 30 processes the input sensing signal through the readout wiring 700. In more detail, the signal processor 30 may convert the sensing signal, which is an analog signal, into a digital signal.

In addition, the signal processor 30 may sample only the sensing signal input when the second thin film transistor 400 is turned on by the second driving signals GS21, GS22...

The liquid crystal display according to the exemplary embodiment includes a system for controlling the driver 20 and interpreting a digital signal input from the signal processor 30. That is, the central processing unit included in the system may generate a control signal for controlling the driver 20, interpret the digital signal, and calculate a position where a touch or the like is input.

As shown in FIG. 5, the liquid crystal panel 10 may be driven by the display period DP and the porch PO.

For example, a period during which the liquid crystal display device is driven may be divided into the display period DP and the porch PO. Here, the display period DP is a period during which the components of the liquid crystal display according to the embodiment operate to display an image. In addition, the porch PO is a period in which the components operate for a purpose other than displaying an image.

That is, the components operate to display an image during the display period DP, and the components do not operate to display an image during the porch PO.

That is, the pixel data generated by the data driver 22 is applied to the pixel electrodes 500 during the display period DP. In addition, the pixel data is not applied to the pixel electrodes 500 during the porch PO.

The display period DP and the porch PO alternate in time with each other.

In addition, the liquid crystal panel 10 may display an image during the display period DP and may not display an image during the porch PO. Therefore, in order to prevent the image being disconnected and recognized at a time, the porch PO may be very short compared to the display period DP.

6 and 7, the first driving signals GS11, GS12... Are applied to the gate lines 100 during the display period DP, and the first driving signals GS11, GS12... 2 driving signals GS21, GS22... May be applied to the gate lines 100.

That is, during the porch PO, only the second thin film transistors 400 are turned on, and the first thin film transistors 300 are not turned on.

Accordingly, the sensing signal stored in the second storage capacitor Cst2 is input to the signal processor 30 through the readout wire 700. The signal processor 30 samples the sensing signal, converts the sensing signal into a digital signal, and transmits the converted signal to the system.

At this time, the system analyzes the digital signal input from the signal processor 30. That is, the system determines whether the digital signal is an output signal when the second driving signals GS21, GS22... Are input to the gate gate 100, and from which lead-out wire 700. Analyze whether or not it is output. Accordingly, the system can calculate the X and Y coordinates of the position where the intensity of the input light is changed by a touch by a finger or the like.

As described above, the liquid crystal display according to the exemplary embodiment senses a signal such as a touch input from the outside during the porch PO and displays an image during the display period DP.

Referring to FIG. 8, the liquid crystal display according to the exemplary embodiment may sense a signal such as a touch input from the outside not only during the porch PO but also during the display period DP.

In other words, the first driving signals GS11, GS12... And the second driving signals GS21, GS22... Are sequentially applied to the gate lines 100 during the display period DP.

In this case, the second driving signals GS21 and GS22 may operate only the second thin film transistor 400 without operating the first thin film transistor 300. That is, the second driving signals GS21, GS22... Do not affect the display of the image by the liquid crystal panel 10.

The liquid crystal display according to the embodiment may be driven in a manner different from those of FIGS. 6 and 7 and 8. For example, the liquid crystal display according to the exemplary embodiment may sense a signal input from the outside even when a specific image is maintained.

That is, while the pixel data is stored in the first storage capacitor Cst1, the second driving signals GS21, GS22... May be applied to the gate lines 100.

In this case, the first thin film transistor 300 is not driven by the second driving signals GS21, GS22..., Only the second thin film transistor 400 is driven. Accordingly, while the pixel data stored in the first storage capacitor Cst1 is maintained, the signal processor 30 may receive a sensing signal generated from the sensor unit 600.

That is, since the first thin film transistor 300 is not turned on, the pixel data stored in the first storage capacitor Cst1 may be maintained without being emitted.

The liquid crystal display according to the exemplary embodiment includes the first thin film transistor 300 and the second thin film transistor 400 having different threshold voltages. Accordingly, the first thin film transistor 300 and the second thin film transistor 400 may be driven separately.

Since the second thin film transistor 400 has a lower threshold voltage, only the second thin film transistor 400 may be driven separately. That is, the second thin film transistor 400 may be driven by second driving signals GS21, GS22..., Higher than the second threshold voltage and lower than the first threshold voltage. In this case, the first thin film transistor 300 is not driven by the second driving signals GS21, GS22...

Accordingly, the sensing signal may be output by the second thin film transistor 400 without affecting the operation of the first thin film transistor 300.

That is, the second driving signals GS21, GS22... May be applied to the second thin film transistor 400 when desired, regardless of a process of displaying an image. Accordingly, the sensing signal may be output when desired regardless of the process of displaying the image.

Since an external signal may be sensed during the porch PO, in which the pixel data is not input, noise that may occur during the display period DP may be excluded.

In addition, since the second thin film transistor 400 has a low threshold voltage, the second thin film transistor 400 may operate quickly, and the second driving signals GS21, GS22... At a high frequency may be applied to the second thin film transistor 400. Can be applied.

Accordingly, the liquid crystal display according to the embodiment can sense a signal input from the outside such as a touch for a very short time.

In addition, the liquid crystal display according to the exemplary embodiment may drive only the second thin film transistor 400, and thus may receive a signal from the outside even when the pixel electrodes 500 are not driven.

In this case, the liquid crystal display according to the exemplary embodiment does not need to continuously drive the pixel electrodes 500, thereby reducing power consumption.

In addition, the liquid crystal display according to the exemplary embodiment may sample the sensing signal when desired, thereby reducing the overload of the signal processor 30 and / or the system. Accordingly, the liquid crystal display according to the embodiment can calculate the position of the touch or the like using a complicated algorithm.

Therefore, the liquid crystal display according to the embodiment can more accurately calculate the position where the finger or the like is touched.

Although the liquid crystal display device has been described in the present embodiment, the liquid crystal display device according to the present embodiment displays an image and simultaneously receives a signal such as a touch from the outside.

Therefore, the liquid crystal display device according to the present embodiment is a display device and an input device at the same time.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be understood that various modifications and applications are possible. For example, each component specifically shown in the embodiments can be modified and implemented. It is to be understood that all changes and modifications that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

1 is a circuit diagram illustrating a liquid crystal display according to an embodiment.

2 is a circuit diagram illustrating one pixel.

3 is a cross-sectional view illustrating the first thin film transistor.

4 is a cross-sectional view illustrating a second thin film transistor.

5 is a diagram illustrating a process of operating a liquid crystal display according to an exemplary embodiment.

6 and 7 illustrate a process in which the first driving signal and the second driving signal are applied to the gate lines.

8 is a diagram illustrating a process in which a first driving signal and a second driving signal are applied to gate lines in another manner.

Claims (10)

Gate wiring; A data line crossing the gate line and defining a pixel area together with the gate line; A first thin film transistor driven by a first driving signal applied through the gate wiring and having a first threshold voltage; A second thin film transistor driven by a second driving signal applied through the gate wiring and having a second threshold voltage lower than the first threshold voltage; A pixel electrode and a sensor unit disposed in the pixel area; A signal processing unit processing a sensing signal sensed by the sensor unit; And A lead-out wire connected to the signal processor and transferring the sensing signal to the signal processor; The first thin film transistor selectively connects the data line and the pixel electrode, And the second thin film transistor selectively connects the sensor unit and the lead-out wiring. delete The display device of claim 1, wherein the first driving signal has a higher voltage than the second driving signal. Gate wiring; A data line crossing the gate line and defining a pixel area together with the gate line; A first thin film transistor driven by a first driving signal applied through the gate wiring and having a first threshold voltage; And A second thin film transistor driven by a second driving signal applied through the gate wiring, the second thin film transistor having a second threshold voltage lower than the first threshold voltage, The first thin film transistor is A first gate electrode connected to the gate wiring; And A first channel region corresponding to the first gate electrode, The second thin film transistor is A second gate electrode connected to the gate line; And A second channel region corresponding to the second gate electrode, And a conductive dopant having a lower concentration than that of the second channel region. The method of claim 1, wherein the first driving signal has a higher voltage than the first threshold voltage. The second driving signal is lower than the first threshold voltage and has a voltage higher than the second threshold voltage. A plurality of gate wires disposed in parallel with each other; A plurality of data lines crossing the gate lines; First thin film transistors driven by a first driving signal applied through the respective gate lines and having a first threshold voltage; A plurality of pixel electrodes connected to the first thin film transistors, respectively; Second thin film transistors driven by a second driving signal applied through the respective gate wires and having a second threshold voltage lower than the first threshold voltage; And And a sensor unit connected to the second thin film transistors, respectively. The display apparatus of claim 6, further comprising: a driver connected to the gate lines and configured to generate the first driving signal and the second driving signal; And And a signal processor configured to receive sensing signals generated by the sensor units. The display device of claim 7, wherein the driver applies the first driving signal to the gate lines during a display period. And applying the second driving signal to the gate lines during the porch following the display period. The display device of claim 7, wherein the driver applies the first driving signal and the second driving signal to the gate lines during a display period. Gate wiring; A data line crossing the gate line and defining the gate line and a pixel area; A pixel electrode disposed in the pixel area; A first thin film transistor driven by a first driving signal applied through the gate line, selectively connecting the data line and the pixel electrode, and having a first threshold voltage; A sensor unit disposed in the pixel area and configured to sense external light; And And a second thin film transistor connected to the sensor unit and driven by a second driving signal applied through the gate wiring, the second thin film transistor having a second threshold voltage lower than the first threshold voltage.

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