KR20170117965A - Optical touch screen apparatus and method of driving the optical touch screen apparatus - Google Patents

Abstract

An optical touch screen device using an oxide semiconductor transistor as a light sensing device and a driving method of the optical touch screen device are disclosed. The optical touch screen device includes a plurality of optical sensing pixels for sensing incident light, a gate driver for sequentially providing a gate voltage and a reset signal to each optical sensing pixel, and a data driver for receiving a light sensing signal from each optical sensing pixel, And a signal output unit for outputting the signal. In addition, the gate driver may include a plurality of gate lines arranged in the row direction and at least one reset line. Here, each gate line may be connected to light sensing pixels arranged along the same row, and at least one reset line may be electrically connected to a plurality of light sensing pixels in the optical touch screen device.

Description

TECHNICAL FIELD [0001] The present invention relates to an optical touch screen apparatus and a method of driving the same,

An optical touch screen apparatus and a driving method thereof are disclosed. More particularly, an optical touch screen device using an oxide semiconductor transistor as an optical sensing device and a method of driving the optical touch screen device are disclosed.

A touch screen is a device that can receive input data directly from a screen so that a specific position of the display screen can be detected by a human hand or a pen when the touch is reached and the software can perform a specific process. To this end, a touch screen is added to a general display panel by a device called a touch panel, thereby exerting its function. Such a touch panel includes various types such as a pressure resistive film type, a contact type capacitance type, a surface acoustic wave (SAW) type, an infrared light sensing type, and a piezoelectric type. Recently, a touch screen is widely used in various fields as an input device that can replace a keyboard or a mouse.

A touch screen, which has been widely used so far, is a method of directly touching a display device using a hand or a pen. However, if the distance between the user and the display device is increased as the display device becomes larger and larger, it may be difficult to apply the direct touch method. Accordingly, an optical touch screen capable of sensing light instead of touching a hand or a pen and performing the same function as a conventional touch screen has been proposed. The optical touch screen is expected to be advantageous not only for communication between a user and a terminal but also for communication between a user and a user.

In order to implement the optical touch screen, a light sensing device of a minute size capable of sensing light is required. In general, an amorphous silicon thin film transistor (a-Si TFT) is widely used as a light sensing element. However, in the case of an a-Si TFT, the current change due to light is not sufficiently large. Accordingly, charge generated in the photodiode when light is applied is accumulated in the capacitor for a predetermined time, and a signal related to the light intensity is generated from the amount of charge accumulated in the capacitor. When the capacitor is used as described above, the larger the size of the optical touch screen, the greater the parasitic capacitance.

An optical touch screen device using an oxide semiconductor transistor as an optical sensing element is provided.

Also, a method of driving the optical touch screen device is provided.

An optical touch screen device according to one aspect of the present invention includes an array of a plurality of optical sensing pixels for sensing incident light; A gate driver for providing a gate voltage and a reset signal to each optical sensing pixel; And a signal output unit for receiving a light sensing signal from each light sensing pixel and outputting a data signal, wherein the gate driver includes a plurality of gate lines for providing a gate voltage to each light sensing pixel, And at least one reset line electrically connected to the plurality of light sensing pixels for providing a reset signal to each light sensing pixel.

For example, the array of light sensing pixels may comprise a plurality of light sensing pixels arranged in a plurality of rows and columns.

According to one embodiment, the plurality of gate lines may be arranged in a row direction, and each gate line may be connected to light sensing pixels arranged along the same row.

According to one embodiment, the signal output unit may include a plurality of data lines arranged in a column direction, and each data line may be connected to optical sensing pixels arranged along the same column.

Further, each optical sensing pixel may include, for example, a light sensing transistor for sensing light and a switching transistor for outputting a light sensing signal from the light sensing transistor.

According to one embodiment, the gate line may be connected to the gate of the switching transistor, and the reset line may be connected to the gate of the light sensing transistor.

For example, the light sensing transistor may be an oxide semiconductor transistor using an oxide semiconductor as a material of a channel layer.

The oxide semiconductor may include, for example, a material in which at least one of Hf, Y, Ta, Zr, Ti, Cu, Ni, Cr, In, Ga, Al, Sn and Mg is mixed with ZnO or ZnO have.

According to another aspect of the present invention, there is provided an optical touch screen device for displaying an image and detecting incident light, comprising: an array of a plurality of pixels arranged in a plurality of rows and columns; A gate driver for providing a gate voltage and a reset signal to each pixel; A data driver for providing a video signal to each pixel; And a signal output unit for receiving a light sensing signal from each pixel and outputting a data signal, wherein the gate driver includes a plurality of gate lines for providing a gate voltage to each pixel, And at least one reset line electrically connected to the plurality of pixels to provide a reset signal.

According to one embodiment, the plurality of gate lines may be arranged in the row direction, and each gate line may be connected to pixels arranged along the same row.

Also, according to one embodiment, the signal output unit may include a plurality of optical sensing data lines arranged in a column direction, and each optical sensing data line may be connected to pixels arranged along the same column .

According to an embodiment, the data driver may include a plurality of image data lines arranged in a column direction, and each image data line may be connected to pixels arranged in the same column, To provide a video signal to be displayed on the display device.

According to one embodiment, each of the pixels may include a display pixel portion for displaying an image and an optical sensing pixel portion for sensing incident light, wherein the display pixel portion includes a display cell and on / off of the display cell The light sensing pixel section may include a light sensing transistor for sensing incident light and a second switching transistor for outputting an optical sensing signal from the light sensing transistor.

For example, the gates of the first and second switching transistors may be coupled together to the gate line, and the gate of the light sensing transistor may be coupled to the reset line.

According to one embodiment, the array of pixels comprises: a first pixel including only a display pixel portion for displaying an image; And a second pixel including both the display pixel portion and an optical sensing pixel portion for sensing incident light, wherein the display pixel portion includes a display cell and a first switching transistor for controlling on / off of the display cell, The light sensing pixel unit may include a light sensing transistor for sensing incident light and a second switching transistor for outputting an optical sensing signal from the light sensing transistor.

According to yet another aspect of the present invention, there is provided a method of driving an optical touch screen device, comprising the steps of: when an optical touch screen device stops scanning for each frame, or immediately before scanning for each frame starts, It is possible to simultaneously reset the light sensing pixels.

The driving method of the optical touch screen device may include sequentially applying a gate voltage to the array of a plurality of optical sensing pixels, one row at a time, and sequentially outputting a light sensing signal for each row; And simultaneously resetting the plurality of optical sensing pixels by providing a reset signal to the plurality of optical sensing pixels at a time.

According to one embodiment, the gate voltage and the reset signal may be provided from one data driver.

The data driver may sequentially provide the gate voltage and the reset signal.

Each light sensing pixel may include, for example, a light sensing transistor for sensing light and a switching transistor for outputting a light sensing signal from the light sensing transistor, the gate voltage being applied to the gate of the switching transistor And the reset signal may be provided at the gate of the light sensing transistor.

Since the disclosed optical touch screen device uses an oxide semiconductor transistor having a comparatively good photosensitive characteristic as a light sensing element, a capacitor is not required to perform a light sensing operation. That is, one optical sensing pixel made up of only one light sensing transistor made of an oxide semiconductor transistor and only one switching transistor can be constituted. Accordingly, when the optical sensing device such as the optical touch panel or the image capturing device is implemented using the disclosed optical sensing circuit, the time delay due to the parasitic capacitance can be freed from the time delay, thereby making it easy to increase the area of the optical touch screen device.

In addition, according to the driving method of the optical touch screen device disclosed, since a plurality of optical sensing transistors are simultaneously reset at the same time, a separate driving unit for driving the optical sensing transistor and the switching transistor is not required. Therefore, the configuration of the optical touch screen device can be simplified, and it is possible to obtain effects such as improvement in space usability, reduction in process cost, and reduction in power consumption.

1 is a block diagram schematically showing an overall circuit structure of an optical touch screen device according to an embodiment of the present invention.
2 is a circuit diagram showing an exemplary structure of a light sensing pixel of the optical touch screen device shown in FIG.
3 is a cross-sectional view schematically illustrating an exemplary structure of an oxide semiconductor transistor used as a light sensing element in the light sensing pixel shown in FIG.
4 is a graph exemplarily showing operational characteristics of the oxide semiconductor transistor shown in FIG.
FIG. 5 is a timing diagram exemplarily showing a method of driving the optical touch screen apparatus shown in FIG. 1. FIG.
6 is a circuit diagram showing an exemplary structure of one pixel of an optical touch screen device according to another embodiment of the present invention.
FIG. 7 is a block diagram schematically showing an overall circuit structure of an optical touch screen device according to another embodiment of the present invention including the pixels shown in FIG.
8 is a circuit diagram schematically showing the structure of an exemplary pixel array of an optical touch screen device according to another embodiment of the present invention.

Hereinafter, an optical touch screen device and a driving method thereof will be described in detail with reference to the accompanying drawings. In the following drawings, like reference numerals refer to like elements, and the size of each element in the drawings may be exaggerated for clarity and convenience of explanation.

1 is a block diagram schematically showing an overall circuit structure of an optical touch screen device according to an embodiment of the present invention. Referring to FIG. 1, an optical touch screen device 100 according to an embodiment of the present invention includes a plurality of optical sensing pixels 110 for sensing incident light, a gate voltage and a reset signal for each optical sensing pixel 110 And a signal output unit 130 for receiving a light sensing signal from each light sensing pixel 110 and outputting a data signal.

As shown in FIG. 1, a plurality of optical sensing pixels 110 may be arranged in a plurality of rows and columns. For example, the plurality of optical sensing pixels 110 may be arranged in the form of an array having n rows and m columns. The gate driving unit 120 controls each of the optical sensing pixels 110 to be individually activated to output a light sensing signal from each optical sensing pixel 110. For this purpose, the gate driver 120 may include a plurality of gate lines GATE1, GATE2, ..., GATEn arranged in the row direction and a reset line RESET. Each gate line may be connected to all the optical sensing pixels 110 arranged along the same row. For example, the first gate line GATE1 may be connected to all the optical sensing pixels 110 arranged along the first row, and the nth gate line GATEn may be connected to all of the May be coupled to the optical sensing pixels 110. On the other hand, the reset line RESET serves to provide a reset signal for initializing the light sensing pixels 110 to the light sensing pixels 110. As shown in FIG. 1, one reset line RESET is connected to all the optical sensing pixels 110 in the optical touch screen device 100 at a time. Accordingly, after the light sensing signal is output from the light sensing pixels 110 arranged along the nth row, all the light sensing pixels 110 can be simultaneously initialized through one reset line RESET. Although only one reset line RESET is shown in Fig. 1, the present invention is not limited thereto. For example, in another embodiment, a plurality of reset lines RESET may be coupled to a plurality of optical sensing pixels 110, and a plurality of optical sensing pixels 110 may be coupled to a plurality of reset lines RESET. At the same time, a reset signal may be provided. A method of driving the optical touch screen device 100 will be described in detail later.

The signal output unit 130 receives a light sensing signal generated from each optical sensing pixel 110 and outputs a data signal. For this purpose, the signal output unit 130 may include a plurality of data lines (DATA1, DATA2, ..., DATAm) arranged along the column direction. Each data line DATA1, DATA2, ..., DATAm may be connected to all the optical sensing pixels 110 arranged along the same column. For example, the first data line DATA1 may be connected to all the optical sensing pixels 110 arranged along the first column, and the mth data line DATAm may be connected to all of the May be coupled to the optical sensing pixels 110. In this structure, the signal output unit 130 outputs all optical sensing signals generated from the optical sensing pixels 110 arranged along the same row to a plurality of data lines (DATA1, DATA2, ..., DATAm) . For example, when a gate signal is applied to the first gate line GATE1, all optical sensing signals generated in the optical sensing pixels 110 arranged along the first row are input to the signal output unit 130 . The signal output unit 130 may be configured to convert the optical sensing signals into a digital data signal, and sequentially output the digital data signals one row at a time.

2 is a circuit diagram showing an exemplary structure of a light sensing pixel 110 of the optical touch screen device 100 shown in FIG. Referring to FIG. 2, the optical sensing pixel 110 may include one light sensing transistor 111 and one switching transistor 112, which are connected in series with each other. That is, the source of the light sensing transistor 111 may be connected to the drain of the switching transistor 112. The light sensing transistor 111 is an optical sensing element for sensing light, and may be, for example, an oxide semiconductor transistor to be described later. The switching transistor 112 for outputting the optical sensing signal may be a general thin film transistor having no photosensitivity. 2, the optical sensing pixel 110 includes a gate line GATE connected to the gate of the switching transistor 112, a data line DATA connected to the source of the switching transistor 112, A driving voltage line Vdd connected to the drain of the sensing transistor 111 and a reset line RESET connected to the gate of the optical sensing transistor 111. [ The gate line GATE connected to the gate of the switching transistor 112 may be one of a plurality of gate lines GATE1, GATE2, ..., GATEn connected to the gate driver 120 shown in FIG. The data line DATA connected to the source of the switching transistor 112 may be one of a plurality of data lines DATA1, DATA2, ..., DATAm of the signal output unit 130. [ The reset line RESET may be connected to the gate driver 120 shown in FIG.

In the optical sensing pixel 110 having such a structure, when a gate voltage is applied to the switching transistor 112 through the gate line GATE, the switching transistor 112 is turned ON. Then, a current flows from the source of the light sensing transistor 111 to the data line DATA. At this time, the amount of current flowing from the light sensing transistor 111 to the data line DATA changes according to the intensity of light incident on the light sensing transistor 111. Therefore, by measuring the amount of current flowing through the data line DATA, the intensity of light incident on the light sensing transistor 111 can be calculated. On the other hand, when no gate voltage is applied to the switching transistor 112, the switching transistor 112 is turned off, so that no current flows through the data line DATA.

3 is a cross-sectional view schematically illustrating an exemplary structure of an oxide semiconductor transistor used as a light sensing transistor 111 as a light sensing element in the light sensing pixel 110 shown in FIG. The oxide semiconductor transistor means a transistor using an oxide semiconductor as a channel material. 3, an oxide semiconductor transistor 10 includes a substrate 11, an insulating layer 12 disposed entirely over the substrate 11, a gate 13 partially disposed over the insulating layer 12, A gate insulating film 14 disposed on the insulating layer 12 and the gate 13 to cover the periphery of the gate 13, a channel layer 15 disposed on the gate insulating film 14, the channel layer 15, And a transparent insulating layer 18 disposed so as to cover the source 16, the drain 17 and the second channel layer 15 as a whole can do. Although the oxide semiconductor transistor 10 of the lower gate structure in which the gate 13 is disposed under the channel layer 15 is shown in Fig. 3, the oxide semiconductor transistor 10 may be configured as a top gate structure.

Here, the substrate 11 may be a general substrate material such as glass, silicon, or the like. As the insulating layer 12, the gate insulating film 14, and the transparent insulating layer 18, a material such as SiO ₂ can be used. If the substrate 11 itself is made of an insulating material, the insulating layer 12 on the substrate 11 may be omitted. Further, the gate 13, the source 16 and the drain 17 may use a conductive metal or a conductive metal oxide. For example, when the oxide semiconductor transistor 10 is required to be transparent, the gate 13, the source 16 and the drain 17 may be made of a transparent conductive material such as ITO. However, when the oxide semiconductor transistor 10 is not required to be transparent, the material of the substrate 11, the insulating layer 12, the gate 13, the gate insulating film 14, the source 16 and the drain 17 Is not necessarily transparent.

On the other hand, the channel layer 15 may be made of an oxide semiconductor material, as described above. Depending on the choice of oxide semiconductor material used as the channel layer 15, the oxide semiconductor transistor 10 may have light sensitive properties. For example, a ZnO-based oxide semiconductor may be used as the material of the channel layer 15. [ Examples of the ZnO-based oxide semiconductor include a mixture of ZnO or ZnO mixed with at least one of Hf, Y, Ta, Zr, Ti, Cu, Ni, Cr, In, Ga, Al, can do. Typical examples of such an oxide semiconductor material include ZnO, TaZnO, InZnO (IZO), and GaInZnO (GIZO). When such a material is used as the channel layer 15, since the oxide semiconductor transistor 10 shown in FIG. 3 has a characteristic in which the threshold voltage and the drain current vary according to the wavelength or light amount of incident light, have.

FIG. 4 is a graph exemplarily showing operational characteristics of the oxide semiconductor transistor 10 shown in FIG. 3, showing the drain current characteristics with respect to the gate voltage. Referring to FIG. 4, when light is incident on the oxide semiconductor transistor 10, it can be seen that the drain current greatly increases when light is not incident at a gate voltage lower than the threshold voltage (that is, when the transistor is OFF). 4, the current ratio between the drain current when the light is incident on the oxide semiconductor transistor 10 and the drain current when the light is not incident is considerably large. Therefore, when the oxide semiconductor transistor 10 is used as a light sensing element, it can have various advantages. For example, since the oxide semiconductor transistor 10 has a large current ratio, a photocurrent of a relatively large magnitude of several tens nA to several hundred nA at the time of light incidence can be generated. 2, the light sensing pixel 110 can be simply constituted by only the light sensing transistor 111 and the switching transistor 112 without a capacitor, . As a result, the optical touch screen device 100 can be made large-sized, and the driving speed and power consumption can be reduced.

Referring again to FIG. 4, the oxide semiconductor transistor 10 exhibits different characteristics depending on the sweep direction of the gate voltage at the time of light incidence. For example, the first graph indicated by '1' in FIG. 4 shows the characteristic of sweeping from the negative voltage to the positive voltage in the direction of increasing the gate voltage, and the second graph indicated by '2' And shows a characteristic in the case of sweeping from a voltage to a negative voltage in the direction of decreasing the gate voltage. As shown in the first graph, when the gate voltage sweeps in the positive direction, the threshold voltage of the oxide semiconductor transistor 10 appears to move in the negative direction at the time of light incidence. On the other hand, when the gate voltage is swept in the negative direction as in the second graph, only the off current is increased while the threshold voltage of the oxide semiconductor transistor 10 is maintained at the time of light incidence. In particular, when the gate voltage is swept in the positive direction as shown in the first graph, the drain current is not lowered even if the incident light is stopped in the oxide semiconductor transistor 10, so that the light dependence of the drain current hardly appears.

The characteristic difference between the gate voltages in the sweep direction is similar to the phenomenon used for recording data in a general flash memory and is a phenomenon in which charges are trapped in or inside the channel layer 15 of the oxide semiconductor transistor 10 ≪ / RTI > For example, when a large negative voltage (for example, a voltage lower than the threshold voltage) is applied to the gate with light, holes generated by light in the channel layer 15 pass through the gate insulating film 14 and the channel Layer 15 to be trapped. These trapped charges are not removed until a sufficiently large positive voltage is applied to the gate. Thus, once the charge is trapped, it can be seen that the gate current is not lowered even after the incidence of light is stopped. This phenomenon disappears when a trapped charge is removed by applying a positive voltage to the gate. That is, since the oxide semiconductor transistor 10 may have a deteriorated photosensitive characteristic due to a charge trap phenomenon that occurs while a negative voltage is applied to the gate, a positive voltage is periodically applied to the gate of the oxide semiconductor transistor 10 It needs to be initialized.

Referring again to FIG. 1, the reset line RESET of the gate driver 120 periodically applies a positive gate voltage to the light sensing transistor 111 (see FIG. 2) in the light sensing pixel 110, Thereby maintaining the photosensitive characteristics of the light emitting device 111. FIG. 5 is a timing diagram illustrating a method of driving an optical touch screen device 100 including the oxide semiconductor transistor 10 as the light sensing transistor 111. Referring to FIG. 5, the gate driver 120 applies a high voltage (that is, a voltage equal to or higher than the threshold voltage of the switching transistor 112) to the first row through the first gate line GATE1, And outputs a light sensing signal from the sensing pixels 110. At this time, a low voltage is applied to the remaining gate lines GATE2 to GATEn and the reset line RESET. Then, the gate driver 120 applies a high voltage through the second gate line GATE2 to output a light sensing signal from the light sensing pixels 110 in the second row. At this time, a low voltage is applied to the remaining gate lines GATE1, GATE3 to GATEn and the reset line RESET. After outputting the light sensing signal from the light sensing pixels 110 in the nth row in this manner, a high voltage is applied to the reset line RESET. Since the reset line RESET is connected to all the light sensing pixels 110, the light sensing transistors 111 in all the light sensing pixels 110 can be initialized at the same time. Thus, the light sensing operation for one frame is completed, and then the light sensing operation for the next frame can be repeated in the same order as described above. That is, the light sensing transistors 111 in all the optical sensing pixels 110 can be initialized at the same time when the scanning for each frame ends. However, depending on the embodiment, the initialization of the optical sensing transistors 111 may be started first. For example, just prior to the start of scanning for each frame, the light sensing transistors 111 in all the optical sensing pixels 110 can be initialized at the same time.

As described above, the optical touch screen device 100 shown in FIG. 1 includes only one reset line RESET connected to all the optical sensing pixels 110 at a time. Therefore, the light sensing transistors 111 in all of the light sensing pixels 110 can be initialized simultaneously with a single high voltage through one reset line RESET. The reset line RESET connected to the gate of the light sensing transistor 111 and the gate lines GATE1 to GATEn connected to the gate of the switching transistor 112 are all connected to the same gate driver 120 Therefore, the light sensing transistor 111 and the switching transistor 112 in the light sensing pixel 110 can be controlled by only one gate driver 120. Therefore, a separate driving unit for separately driving the light sensing transistor 111 and the switching transistor 112 is not required. Accordingly, the configuration of the optical touch screen device 100 can be simplified, so that effects such as improvement in space usability, reduction in process cost, and reduction in power consumption can be obtained.

Due to such a space saving, an in-cell type optical touch screen device in which display pixels and optical sensing pixels are integrated into one can be easily implemented. 6 is a circuit diagram showing an exemplary structure of one pixel 210 of an in-cell type optical touch screen device. Referring to FIG. 6, one pixel 210 of the in-cell type optical touch screen device includes a display pixel portion 210d and a light sensing pixel portion 210s. The display pixel unit 210d may include a display cell (e.g., a liquid crystal cell in the case of an LCD) 212 and a first switching transistor 211 for controlling on / off of the display cell 212. [ The light sensing pixel portion 210s may include a light sensing transistor 213 for sensing incident light and a second switching transistor 214 for outputting a light sensing signal from the light sensing transistor 213. Specifically, the gates of the first and second switching transistors 211 and 214 are connected to one gate line GATE. The drain of the first switching transistor 211 is connected to the image data line LCD-DATA and the source thereof may be connected to the display cell 212. Also, the source of the second switching transistor 214 is connected to the optical sensing data line (SENSOR-DATA), and the drain can be connected to the source of the optical sensing transistor 213. The drain of the light sensing transistor 213 is connected to the driving voltage line Vdd, and the gate thereof is connected to the reset line RESET.

FIG. 7 is a block diagram showing the overall circuit structure of the in-cell type optical touch screen device 200 including the pixels 210 shown in FIG. 7, the optical touch screen device 200 sequentially displays a gate voltage and a reset signal to an array 250 of a plurality of pixels 210 that display an image and sense incident light, and each pixel 210 A data driver 240 for providing a video signal to each pixel 210 and a signal output unit 240 for receiving a light sensing signal from each pixel 110 and outputting a data signal, 230). Although only one pixel 210 is shown in FIG. 7 for convenience, a plurality of actual pixels 210 are arranged in the form of an array.

As shown in FIG. 7, the gate driver 220 may include a plurality of gate lines GATE1 to GATEn arranged in the row direction and a reset line RESET. Each gate line may be connected to all the pixels 210 arranged along the same row. For example, the first gate line GATE1 may be connected to the gate of the first switching transistor 211 and the gate of the second switching transistor 214 in all the pixels 210 arranged along the first row . In addition, the reset line RESET is connected to all the pixels 210 in the optical touch screen device 200 at a time. The signal output unit 230 may include a plurality of optical sensing data lines SENSOR-DATA1 to SENSOR-DATAm arranged in the column direction. Each of the optical sensing data lines SENSOR-DATA1 to SENSOR-DATAm may be connected to all the pixels 210 arranged along the same column. The signal output unit 230 may receive a light sensing signal generated from each pixel 210 through each of the optical sensing data lines SENSOR-DATA1 to SENSOR-DATAm, and may output a data signal. In addition, the data driver 240 may include a plurality of image data lines (LCD-DATA1 to LCD-DATAm) arranged along the column direction. Each of the image data lines (LCD-DATA1 to LCD-DATAm) is connected to all the pixels 210 arranged along the same column. The data driver 240 provides a video signal to be displayed on each pixel 210 through each video data line (LCD-DATA1 to LCD-DATAm).

The optical touch screen device 200 shown in FIG. 7 is a device in which a display panel and an optical touch screen panel are integrated in a single panel, and can simultaneously display an image and sense an incident light. For example, when a high voltage is applied through the first gate line GATE1, all the pixels 210 arranged along the first row display an image, and at the same time, detect the incident light to output a light sensing signal. After the pixels 210 arranged along the nth row display an image and output a light sensing signal, all of the light sensing transistors 213 in all the pixels 210 through one reset line RESET ) Can be initialized at the same time. Particularly, since the light sensing transistor 213 in the pixel 210 and the first and second switching transistors 211 and 214 can be controlled by one gate driver 220, a separate additional driving unit is not required Do not. 7, a plurality of driving units, such as the gate driving unit 220, the signal output unit 230, and the data driving unit 240, may be mounted on a single substrate without interfering with the space. It can be easily arranged.

7, all of the pixels 210 include the light sensing pixel portion 210s. However, it is also possible that only the light sensing pixel portion 210s is included in only some of the pixels 210. FIG. In a typical display panel, one pixel has a width and height of about 200-300 μm, while incident light has a beam diameter of about 2 mm, which is much larger. Therefore, even when the light sensing pixel portion 210s is partially disposed, it is possible to specify the incident position of the incident light. 8 is a circuit diagram schematically showing the structure of an exemplary pixel array 260 in which the light sensing pixel portion 210s is partially arranged according to this consideration.

8, the pixel array 260 may include a pixel 210 in which the light sensing pixel portion 210s is disposed and a pixel 210 'in which the light sensing pixel portion 210s is not disposed. have. That is, the pixel 210 'may include only the display pixel portion 210d. For example, as shown in FIG. 8, the light sensing pixel portion 210s may be arranged for every four pixels. However, this is merely an example, and the light sensing pixel portion 210s may be arranged for every fewer or more pixels depending on the embodiment. Each of the display pixel units 210d may further include a red sub-pixel R, a green sub-pixel G and a blue sub-pixel B for color representation.

Up to now, an exemplary embodiment of an optical touch screen device and a method of driving the same has been described and shown in the accompanying drawings to facilitate understanding of the present invention. It should be understood, however, that such embodiments are merely illustrative of the present invention and not limiting thereof. And it is to be understood that the invention is not limited to the details shown and described. Since various other modifications may occur to those of ordinary skill in the art.

10 ..... oxide semiconductor transistor 11 ..... substrate
12 ..... insulation layer 13 ..... gate
14 ..... gate insulating film 15 ..... channel layer
16 ..... source 17 ..... drain
18 ..... transparent insulating layer 100, 200 .... optical touch screen device
110, 210 .... pixels 111, 213 .... light sensing transistor
112, 211, 214 .... Switching transistors 120, 220 .... Gate driver
130, 230 .... Signal output unit 240 .... Data driver
250, 260 .... pixel array

Claims (22)

An array of a plurality of light sensing pixels arranged along a plurality of rows and a plurality of columns by sensing incident light;
A gate driver for providing a gate voltage and a reset signal to each optical sensing pixel; And
And a signal output unit for receiving a light sensing signal from each light sensing pixel and outputting a data signal,
The gate driver may include a plurality of gate lines for providing a gate voltage to each optical sensing pixel, and at least one gate line for providing a reset signal to each optical sensing pixel, A reset line,
Wherein the plurality of gate lines and the one reset line are arranged in a row direction,
Wherein the one reset line is connected to all light sensing pixels arranged over the plurality of rows to simultaneously reset all light sensing pixels arranged over a plurality of rows. The method according to claim 1,
Wherein the array of light sensing pixels comprises a plurality of light sensing pixels arranged in a plurality of columns and rows. 3. The method of claim 2,
Wherein the plurality of gate lines are arranged in a row direction and each gate line is connected to optical sensing pixels arranged along the same row. 3. The method of claim 2,
Wherein the signal output portion includes a plurality of data lines arranged in a column direction, each data line being connected to optical sensing pixels arranged along the same column. The method according to claim 1,
Each optical sensing pixel including a light sensing transistor for sensing light and a switching transistor for outputting a light sensing signal from the light sensing transistor. 6. The method of claim 5,
Wherein the gate line is connected to the gate of the switching transistor and the reset line is connected to the gate of the light sensing transistor. 6. The method of claim 5,
Wherein the optical sensing transistor is an oxide semiconductor transistor using an oxide semiconductor as a material of a channel layer. 8. The method of claim 7,
Wherein the oxide semiconductor includes a material in which at least one of Hf, Y, Ta, Zr, Ti, Cu, Ni, Cr, In, Ga, Al, Sn and Mg is mixed with ZnO or ZnO. An array of a plurality of pixels arranged in a plurality of rows and columns for displaying images and sensing incident light;
A gate driver for providing a gate voltage and a reset signal to each pixel;
A data driver for providing a video signal to each pixel; And
And a signal output unit for receiving a light sensing signal from each pixel and outputting a data signal,
The gate driver includes a plurality of gate lines for providing a gate voltage to each pixel, and only one reset line electrically connected to the plurality of pixels for providing a reset signal to the plurality of pixels,
Wherein the plurality of gate lines and the one reset line are arranged in a row direction,
Wherein the one reset line is connected to all pixels arranged across the plurality of rows to simultaneously reset all pixels arranged across the plurality of rows. 10. The method of claim 9,
Wherein the plurality of gate lines are arranged in a row direction and each gate line is connected to pixels arranged along the same row. 10. The method of claim 9,
Wherein the signal output unit includes a plurality of optical sensing data lines arranged in a column direction and each optical sensing data line is connected to pixels arranged along the same column. 10. The method of claim 9,
The data driver may include a plurality of image data lines arranged in a column direction, each image data line being connected to pixels arranged along the same column, for providing a video signal to be displayed on each pixel, Screen device. 10. The method of claim 9,
Each pixel includes a display pixel portion for displaying an image and a light sensing pixel portion for sensing incident light,
Wherein the display pixel section includes a display cell and a first switching transistor for controlling ON / OFF of the display cell,
Wherein the optical sensing pixel portion includes an optical sensing transistor for sensing incident light and a second switching transistor for outputting an optical sensing signal from the optical sensing transistor. 14. The method of claim 13,
Wherein the gates of the first and second switching transistors are coupled together to the gate line and the gate of the light sensing transistor is coupled to the reset line. 14. The method of claim 13,
Wherein the optical sensing transistor is an oxide semiconductor transistor using an oxide semiconductor as a material of a channel layer. 16. The method of claim 15,
Wherein the oxide semiconductor includes a material in which at least one of Hf, Y, Ta, Zr, Ti, Cu, Ni, Cr, In, Ga, Al, Sn and Mg is mixed with ZnO or ZnO. 10. The method of claim 9,
The array of pixels comprising:
A first pixel including only a display pixel portion for displaying an image; And
And a second pixel including both the display pixel portion and an optical sensing pixel portion for sensing incident light,
Wherein the display pixel section includes a display cell and a first switching transistor for controlling ON / OFF of the display cell,
Wherein the optical sensing pixel portion includes an optical sensing transistor for sensing incident light and a second switching transistor for outputting an optical sensing signal from the optical sensing transistor. And simultaneously resetting a plurality of optical sensing pixels in the optical touch screen device immediately before scanning of each frame of the optical touch screen device ends or before scanning of each frame starts. 19. The method of claim 18,
Sequentially applying a gate voltage to the plurality of arrays of optical sensing pixels one row at a time and sequentially outputting a light sensing signal for each row; And
And simultaneously resetting the plurality of optical sensing pixels by providing a reset signal to the plurality of optical sensing pixels at a time. 20. The method of claim 19,
Wherein the gate voltage and the reset signal are provided from one data driver. 21. The method of claim 20,
Wherein the data driver sequentially provides the gate voltage and the reset signal. 20. The method of claim 19,
Each light sensing pixel including a light sensing transistor for sensing light and a switching transistor for outputting a light sensing signal from the light sensing transistor, the gate voltage being provided at a gate of the switching transistor, And a gate of the optical sensing transistor.

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