KR101382119B1 - Display device of thin film transistor comprising touch sensor and manufacturing method thereof - Google Patents

Abstract

The present invention provides a thin film transistor display device having a touch sensor including a gate electrode formed on a first substrate, a gate insulating film formed on the first substrate and the gate electrode, and a sensing space formed inside the gate insulating film. To provide.

Description

Thin-film transistor display device with built-in touch sensor and manufacturing method {DISPLAY DEVICE OF THIN FILM TRANSISTOR COMPRISING TOUCH SENSOR AND MANUFACTURING METHOD THEREOF}

The present invention relates to a method for high sensitivity touch sensing using a thin film transistor.

The touch screen embedded LCD according to the related art includes a color filter substrate including a plurality of color filters, a thin film transistor substrate including a plurality of pixels, and a polarizer plate attached to the outside of the color filter substrate and the thin film transistor substrate, respectively. In the touch screen embedded liquid crystal display, when the substrate is pressed, the column spacer is pressed by the elastic force of the column spacer so that the column spacer contacts the lower plate to apply a touch signal.

In order to increase the touch sensitivity, the touch screen embedded liquid crystal display reduces the number of column spacers within the allowable cell gap uniformity so that the top plate, that is, the color filter substrate, can be pressed with a small force. Nevertheless, in the case of the point touch mode, the touch level is 80gf to 100gf / cm ² , and in the case of the plane touch mode, the touch is performed at the level of 350 to 400gf / cm ² . Therefore, even in the surface touch mode, there is a need to improve the touch sensitivity to the same level as in the point touch mode.

One embodiment of the present invention provides a thin film transistor display device with a built-in touch sensor and a method of manufacturing the same, by which a touch can be detected using a gate insulating film constituting the thin film transistor without a separate device or an additional deposition layer. do.

According to one embodiment of the present invention, a thin film transistor display device with a built-in touch sensor capable of easily detecting a touch according to a change in a space formed between the gate electrode and the second gate insulating film even when the pressure for pressing the display panel is not large. It provides a manufacturing method.

An embodiment of the present invention provides a thin film transistor display device having a touch sensor and a method of manufacturing the same, which can easily sense a touch using a current value that is changed by a pressure of the display panel.

According to an exemplary embodiment of the present invention, a thin film transistor display device having a touch sensor includes a gate electrode formed on a first substrate, a gate insulating film formed on the first substrate and the gate electrode, and a patterned inside of the gate insulating film. It includes a sensing space formed by. The gate insulating layer on which the sensing space is formed may be formed on the first substrate to have a structure covering the first gate insulating layer formed to cover the gate electrode and the first gate insulating layer. The volume of the sensing space is changed by the pressure applied to the sensing space so that a touch can be sensed.

According to one embodiment of the present invention, a touch can be sensed using a gate insulating film constituting the thin film transistor without a separate device or an additional deposition film, thereby simplifying the manufacturing process.

According to the exemplary embodiment of the present invention, the touch may be easily sensed according to the change of the space formed between the gate electrode and the second gate insulating layer even when the pressure for pressing the display panel is not large.

According to an embodiment of the present invention, the touch can be easily sensed by using a current value that is changed by the pressure of the display panel.

1 is a cross-sectional view of a thin film transistor display device having a touch sensor according to an embodiment of the present invention.
2 is a cross-sectional view of a thin film transistor display device having a touch sensor when touched.
3 is an equivalent circuit diagram illustrating a thin film transistor display device having a touch sensor according to an embodiment of the present invention.
4 is an equivalent circuit diagram illustrating a thin film transistor display device having a touch sensor according to another embodiment of the present invention.
5 is a schematic diagram illustrating a thin film transistor display device having a touch sensor including a pixel circuit according to an active matrix method.
6 is a flowchart illustrating a method of manufacturing a thin film transistor display device having a touch sensor according to an embodiment of the present invention.

Hereinafter, the configuration and operation according to the present invention will be described in detail with reference to the accompanying drawings. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following description with reference to the accompanying drawings, the same reference numerals denote the same elements regardless of the reference numerals, and redundant description thereof will be omitted. The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

According to the present invention, a sensing space is formed in the gate insulating film itself constituting the thin film transistor so that a touch can be sensed, thereby improving the efficiency of the manufacturing process, and the gate electrode gate electrode and SUMMARY A display device including a touch sensor having a structure capable of easily detecting a touch according to a change in a space formed between a second gate insulating layer is provided.

1 is a cross-sectional view of a thin film transistor display device having a touch sensor according to an embodiment of the present invention.

Referring to FIG. 1, a thin film transistor display device (hereinafter, referred to as a “display device”) having a touch sensor according to the present invention may include a gate electrode 10 formed on a first substrate 100 and the first substrate. And a touch sensor including a gate insulating film formed on the gate electrode 10 and a sensing space part 30 formed inside the gate insulating film. That is, it is characterized by implementing a structure in which a space region (detection space portion) having an empty structure is provided inside the gate insulating film.

The gate insulating film may be implemented in a structure that is implemented in one independent layer. However, an embodiment of the present invention will be described as an example in which a sensing space is formed through two insulating layers. That is, the sensing space part 30 according to the present invention includes a first gate insulating film 20a formed to cover the gate electrode 10 and a first gate insulating film 20a formed to cover the first gate insulating film 20a. It may be implemented as a structure for forming an empty space region between the two gate insulating film 20b.

Therefore, in the structure of the touch sensor according to the present invention, a separate element or a deposition film is not required, and a space region (sensing space portion) is formed inside the structure of the gate insulating film, and according to the pressure applied to the sensing space portion. It is possible to implement sensing by detecting a change in the volume of the sensing sensing unit.

The configuration of a display device including a touch sensor according to the present invention including the technical gist of the present invention will be described in detail with reference to FIG. 2.

The display device including the touch sensor according to the present invention includes a first substrate 100, a touch sensor, a second substrate 200, a column spacer 210, a black matrix 220, a liquid crystal 230, and a color filter. And 240.

The display device according to the present invention displays an image by adjusting the light transmittance of the liquid crystal using an electric field. In this case, the pixel electrode 80 disposed to face the first substrate 100 and the second substrate 200. And the liquid crystal 230 are driven by an electric field formed between the common electrode and the common electrode. The first substrate 100 and the second substrate 200 may be formed of an insulating transparent substrate.

The first substrate 100 includes a driving element, a sensing element, and a switching element in a region where the data line and the gate line cross each other. The gate electrode 10 of the driving device, the sensing device, and the switching device may be formed on the first substrate 100, and a gate insulating layer may be formed on the first substrate 100 and the gate electrode 10. The sensing space part 30 may be formed by patterning the inside of the gate insulating layer.

In the present invention, the gate insulating film may be divided into a first gate insulating film 20a and a second gate insulating film 20b. The first gate insulating layer 20a may be formed on the first substrate 100 and may cover the gate electrode 10. The second gate insulating film 20b may be formed to cover the first gate insulating film 20a, and the sensing space part 30 may be formed therebetween.

More specifically, a nitride film is formed from the first gate insulating film, an oxide film having a high selectivity is deposited, and a pattern for forming the sensing space is formed. The nitride film and the activation layer are formed as a second gate insulating film on the pattern. When the n + silicon layer is continuously deposited and patterned, a contact hole is formed, and an oxide film is etched, an empty space is formed between the first gate insulating film 20a and the second gate insulating film 20b with a small thickness. It can be implemented in a structure that is. In addition, a protective layer 70 is disposed on the upper surface of the first gate insulating layer 20a, and an activation layer, an N + layer, a source electrode and a drain electrode of the driving device are disposed between the first gate insulating layer 20a and the protective layer 70. The source electrode 60a, the drain electrode 60b, and the pixel electrode 80 of the sensing element and the switching element are formed.

The sensing space part 30 may be formed between the gate electrode 10 and the second gate insulating layer 20b. Therefore, the touch sensor may sense the touch by changing the volume of the sensing space 30 by the pressure applied to the sensing space 30. For example, in the touch sensor, the volume of the sensing space is reduced by the pressure, and the gap between the gate and the active layer is reduced, thereby increasing the capacitance of the thin film transistor. As a result, when the current value of the thin film transistor changes and the changed current value is greater than or equal to the reference current value, it may be determined that the touch is sensed.

The second substrate 200 may be disposed to face the first substrate 100, and a column spacer 210 may be disposed between the first substrate 100 and the second substrate 200. .

In this case, one end of the column spacer 210 is disposed on the first substrate 100, and the other end is disposed on the second substrate 200, so that the first substrate 100 and the second substrate 200 are separated from each other. The cell gap is maintained at regular intervals. The column spacer 210 may be disposed at a position corresponding to an upper portion of the sensing space 30.

In addition, a black matrix 220 may be disposed between the second substrate 200 and the column spacer 210. In this case, one end of the column spacer 210 may be formed to contact the black matrix 220. The black matrix 220 is to block light, and red, green, and blue color filters 240 may be formed on the black matrix 220.

In the touch sensor according to the present invention, the space of the sensing space 30 is narrowed according to the pressure pressed by the column spacer 210, thereby detecting a touch. The sensing space 30 is formed by forming a first gate insulating film as a nitride film, forming a pattern after deposition of an oxide film having a high selectivity, and forming a second gate insulating film as a nitride film, and then performing a via hole process and forming an intermediate film. The etching may be performed by forming an empty space between the sensing space portion, that is, the first gate insulating film and the second gate insulating film, in the shape of the oxide film pattern. That is, the patterning process of forming the sensing space part 30 may be implemented using a material having an etching selectivity higher than that of the materials constituting the first gate insulating film 20a and the second gate insulating film 20b.

An activation layer such as amorphous silicon 40 and n + amorphous silicon 50 may be formed on the second gate insulating layer 20b. The active layer may include amorphous silicon, polycrystalline silicon crystallized from amorphous silicon, pentacene, thiophene oligomers, low pressure chemical vapor deposition (LPCVD), or plasma plasma (CVD). It can be composed of any one of polycrystalline silicon, and oxide semiconductor deposited using a deposition method of Enhanced Chemical Vapor Deposition.

2 is a cross-sectional view of a thin film transistor display device having a touch sensor when touched.

Referring to FIG. 2, before the touch is performed, the space of the sensing space part 30 maintains a shape formed by the second gate insulating film 20b while maintaining a constant pressure as shown in FIG. 1. However, after being touched, the space of the sensing space unit 30 changes as shown in FIG. 2.

That is, when the second substrate 200 is pressed, the column spacer 210 moves toward the first substrate 100 due to the pressure to be pressed, and the space of the sensing space 30 is narrowed. In the touch sensor, the volume of the sensing space is reduced by the pressure, and the gap between the gate and the active layer is reduced, thereby increasing the capacitance of the thin film transistor. As a result, when the current value of the thin film transistor changes and the changed current value is greater than or equal to the reference current value, it may be determined that the touch is sensed.

The change in the thin film transistor current value due to the capacitance difference can be obtained through the relationship between C and I _D in Equation (1).

I _D is the drain current of the thin film transistor, C is the capacitance between the gate and the active layer, μ _n is the field effect mobility, W is the width of the thin film transistor, L is the length of the thin film transistor, and V _G is The gate voltage, V _TH is a threshold voltage, and V _D is a drain voltage.

As shown in Equation 1, as the capacitance of the thin film transistor increases, the current value increases linearly, and when the changed current value is greater than or equal to the reference current value, it may be determined that the touch is sensed.

In the conventional touch sensor method, a column spacer is made of a conductive material, and an electrode is provided on the lower plate to contact the electrode, and a conductive pixel is sensed. Due to the rain, there was a disadvantage of increasing the unit price. However, in the present invention, since the pressure of the upper plate only needs to be transmitted to the lower plate, the conductivity of the column spacer is not necessary, and thus, the process cost can be reduced.

In addition, the touch sensor method embedded in the conventional display can be sensed by conducting a challenge when the column spacer is exactly in contact with the electrode formed on the lower plate at a certain pressure or greater, but in the present invention, the sensing space portion by the column spacer The touch may be sensed even when the space of 30 is changed even a little and the current value is changed. Accordingly, the present invention can implement a display device incorporating a high sensitivity touch sensor.

3 is an equivalent circuit diagram illustrating a thin film transistor display device having a touch sensor according to an embodiment of the present invention.

Referring to FIG. 3, the display device includes a display scan line and a data input line connected to a driving element (switching TFT) for driving the display device, a drain terminal connected to a power electrode, a source terminal connected to a sensor signal lead-out line, and a gate A sensing element (sensor TFT) having a terminal connected to the sensor scan line and a storage capacitor C _st1 connected to one end of the drain electrode of the driving element and connected to the common voltage line may be configured. When a touch due to pressure occurs in the pixel of the touch sensor having such a configuration, the current of the sensor TFT is increased, and the sensor is connected via the sensor signal lead-out line when the sensor scan line applies the On signal to the corresponding pixel. It can be detected by the signal readout circuit.

The display device includes a liquid crystal capacitor C _lc formed at each sub pixel region defined by an intersection of a gate line and a data line, a driving element formed at each intersection thereof and connected to a liquid crystal cell, and connected in parallel with the liquid crystal capacitor C _lc . Storage capacitor C _st1 .

The driving element supplies a data signal from the data line to the liquid crystal cell C _lc in response to a scan signal from the gate line. The liquid crystal cell C _lc is connected to the driving element, and the pixel electrode formed on the first substrate overlaps the common electrode of the second substrate with the liquid crystal interposed therebetween, thereby forming a capacitor. In addition, one pixel is implemented by a combination of three liquid crystal cells C _lc each including a color filter of red, green, and blue colors.

The pixels of the touch sensor may be formed to correspond to the pixels of the display device, or smaller than the pixels of the display device.

4 is an equivalent circuit diagram illustrating a thin film transistor display device having a touch sensor according to another embodiment of the present invention.

Referring to FIG. 4, a pixel of the touch sensor of FIG. 3 may include a sensor thin film transistor (sensor TFT), a switching thin film transistor (switching TFT2), and a sensor capacitance Cst ₂ . In this case, the sensor TFT may be connected to a sensor gate voltage line having a constant voltage rather than a scan line to maintain an On state or to maintain an operating state of a saturated region in which a constant current flows. Electric current is stored in the sensor capacitance due to the current flowing in that state, and in the case of a pixel in which a touch is generated, the current through the sensor TFT increases and more charge is stored in the sensor capacitance, so that no touch is generated. When the display scan line is applied with the On signal, the difference in the amount of charge can be sensed in the sensor signal readout circuit connected through the sensor signal leadout line.

5 is a schematic diagram illustrating a thin film transistor display device having a touch sensor including a pixel circuit according to an active matrix method.

Referring to FIG. 5, the display apparatus includes a sensor signal readout circuit for driving a plurality of sensor signal readout lines 23, a scan line driver circuit for driving a plurality of scan lines 21, and a plurality of display data input lines 22. It includes a data driving circuit for driving ().

The pixel 24 of the display device and the pixel 25 of the touch sensor include a switching transistor TFT connected to a plurality of scan lines, a plurality of sensor signal readout lines, and a plurality of display data input lines to switch each pixel. .

When a sensor signal is generated by the pressure, the pixel 25 of the touch sensor may sense a touch by transferring a difference value of current to the sensor signal readout circuit.

In addition, when the charge amount is changed by the pressure, the pixel 25 of the touch sensor may store the changed charge amount in the pixel capacitance, and transmit a difference value of the charge amount to the sensor signal readout circuit to detect the touch. As illustrated in FIG. 5, the touch sensor pixels 25 may be embedded in the same number as the pixels of the display device. However, the touch sensor pixels 25 may be embedded with a smaller number of pixels at regular intervals.

6 is a flowchart illustrating a method of manufacturing a thin film transistor display device having a touch sensor according to an embodiment of the present invention.

Referring to FIG. 6, a method of manufacturing a thin film transistor display device having a touch sensor (hereinafter, referred to as a “manufacturing method”) may be performed in the following order.

First, in step S10, a gate electrode and a first gate insulating film are formed on a first substrate. In this case, the first substrate (lower plate) and the second substrate (top plate) can be formed of an insulating transparent substrate.

Next, in step S20, a pattern for forming a sensing space is formed on the first gate insulating layer. The pattern for forming the sensing space is temporarily formed during the process and is a pattern that is etched away in the process of S40 in the manufacturing method.

In operation S30, a second gate insulating layer, an activation layer, and an N + layer are deposited and patterned on the pattern for forming the sensing space.

In operation S40, after forming a via hole to expose a part of the pattern for the sensing space part, the pattern of the sensing space part formed in the process of S20 is etched. At this time, in the manufacturing method, after forming the first gate insulating film as a nitride film, forming a pattern after deposition of an oxide film having a high selectivity, forming a second gate insulating film as a nitride film, performing a via hole process, and forming an oxide film formed in the middle. When etching, an empty space is formed between the sensing space portion, that is, the first gate insulating film and the second gate insulating film, in the shape of the oxide film pattern.

Thereafter, in the S50 process, a source electrode and a drain electrode are formed on the N + layer.

The touch sensor built in the display device manufactured according to the present invention described above may sense a touch by changing a volume of the space (sensing space portion) by pressure. For example, the touch sensor may determine that the touch is sensed when the current value changes by the pressure and the changed current value is equal to or greater than the reference current value.

In this case, in the process of forming the sensing space according to the present invention, the sensing space may be formed to correspond to the pixels of the display device, or the sensing space may be formed less than the number of pixels of the display device.

While the invention has been shown and described with reference to certain preferred embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. This is possible. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined by the equivalents of the claims, as well as the claims.

100: first substrate 10: gate electrode
20a: first gate insulating film 20b: second gate insulating film
30: sensing space portion 40: amorphous silicon
50: n + amorphous silicon 60a: source electrode
60b: drain electrode 70: protective layer
80: pixel electrode 200: second substrate
210: column spacer 220: black matrix
230: liquid crystal 240: color filter

Claims (15)

A gate electrode formed on the first substrate;
A first gate insulating film formed to cover the gate electrode;
A second gate insulating film formed to cover the first gate insulating film;
A sensing space formed between the first gate insulating film and the second gate insulating film;
Thin film transistor display device with a touch sensor including a.
delete The method according to claim 1,
The touch sensor includes:
A thin film transistor display device with a built-in touch sensor for detecting a touch by changing the volume of the sensing space by the pressure applied to the sensing space.
The method of claim 3,
The touch sensor includes:
The display device with a built-in touch sensor, characterized in that the touch is detected when the current value changes by the pressure and the changed current value is equal to or greater than the reference current value.
The method according to claim 1,
A second substrate disposed opposite the first substrate; And
A column spacer disposed between the first substrate and the second substrate
Further comprising, a thin film transistor display device with a built-in touch sensor.
The method of claim 5,
The column spacer,
And a thin film transistor display device having a touch sensor disposed at a position corresponding to an upper portion of the sensing space.
The method of claim 6,
The touch sensor includes:
A thin film transistor display device with a built-in touch sensor for detecting a touch by changing the volume of the sensing space portion in accordance with the pressure pressed by the column spacer.
The method according to claim 1,
Further comprising an activation layer formed on the second gate insulating film,
The activation layer,
Amorphous Si, Polycrystalline Si Crystallized Amorphous Silicon, Pentacene, Thiophene oligomers, and Low Pressure Chemical Vapor Deposition (LPCVD) or Plasma Enhanced Chemical Vapor Deposition (PECVD) A thin film transistor display device having a touch sensor, comprising one of polycrystalline silicon and an oxide semiconductor deposited by using a deposition method.
The method according to claim 1,
The pixel of the touch sensor,
A thin film transistor display device with a built-in touch sensor is formed to correspond to the pixels of the display device, or less than the number of pixels of the display device.
The method of claim 9,
The display device includes:
A thin film transistor display device with a touch sensor further comprising a sensor signal readout circuit.
The method of claim 10,
The pixel of the touch sensor,
When the sensor signal is generated by the pressure applied to the sensing space portion, the thin film transistor display device with a built-in touch sensor for detecting a touch by transmitting a difference value of the current to the sensor signal readout circuit.
The method of claim 11,
The pixel of the touch sensor,
And storing the changed amount of charge in a pixel capacitance and transferring a difference value of the amount of charge to the sensor signal readout circuit when the amount of charge changes due to the pressure, thereby detecting a touch.
Forming a gate electrode and a first gate insulating film on the first substrate;
Forming a second gate insulating layer, an activation layer, and an N + layer stacked on the first gate insulating layer, and forming a sensing space between the first and second gate insulating layers;
Forming a source electrode and a drain electrode on the N + layer
Method of manufacturing a thin film transistor display device with a touch sensor including a.
The method according to claim 13,
Forming the sensing space portion,
Forming a pattern for forming a sensing space on the first gate insulating film,
Forming the second gate insulating layer, the activation layer, and the N + layer on the pattern for forming the sensing space;
And forming a via hole so that a part of the pattern for the sensing space is exposed, and then etching the pattern.
15. The method of claim 14,
Forming the sensing space portion,
Forming the space corresponding to each pixel of the display device, or forming the sensing space part smaller than the number of pixels of the display device.
Method of manufacturing a thin film transistor display device with a touch sensor including a.

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