In-cell touch display device

Abstract

To provide an in-cell touch display device in which an in-cell touch sensor technology is applied to an organic light emitting display panel.SOLUTION: An in-cell touch display device may include: a substrate; a transistor formation layer formed on the substrate and including a semiconductor, a source electrode, a drain electrode, and a gate electrode; and a light emitting element layer formed on the transistor formation layer and including an anode electrode, an emission layer, and a cathode electrode. A plurality of touch electrodes forming a coupling capacitor with the cathode electrode of the light emitting element layer may be formed in the transistor formation layer.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present disclosure relates to an in-cell touch display device. [Background technology]

[0002] With the development of an information society, various display devices for displaying images have been developed, and touch technology has been developed to apply a touch input method to display devices, which allows users to easily input information or commands intuitively and conveniently.

[0003] In order to apply a touch input method to a display device, a touch panel including a touch sensor must be separately manufactured and combined with the display panel. This method has the disadvantages of increasing the size and thickness of the device and complicating the manufacturing process. For this reason, an in-cell touch sensor technology has been developed that includes a touch sensor in the display panel without the need to separately manufacture a touch panel. Summary of the Invention [Problem to be solved by the invention]

[0004] Designing and manufacturing a display panel including a touch sensor is technically very difficult. Furthermore, when a touch sensor including a plurality of touch electrodes is built into a display panel, the touch sensor is located very close to surrounding display drive electrodes and display drive wiring within the display panel, which may significantly increase the parasitic capacitance between the touch sensor and the display drive electrodes or between the touch sensor and the display drive wiring. The increased parasitic capacitance may lead to a decrease in touch sensitivity.

[0005] In particular, when an in-cell touch sensor technology is applied to a self-emitting organic light-emitting display panel, the parasitic capacitance may become even larger due to the structural characteristics of the organic light-emitting display panel.

[0006] Therefore, an object of the present disclosure is to provide an in-cell touch display device that enables in-cell touch sensor technology to be applied to an organic light emitting display panel.

[0007] The problems to be solved by one embodiment of this specification are not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the following description. [Means for solving the problem]

[0008] An in-cell touch display device according to one aspect of the present disclosure may include a substrate, a transistor formation layer formed on the substrate and including a semiconductor, a source electrode, a drain electrode, and a gate electrode, and a light-emitting element layer formed on the transistor formation layer and including an anode electrode, a light-emitting layer, and a cathode electrode, and a plurality of touch electrodes forming a coupling capacitor with the cathode electrode of the light-emitting element layer may be formed in the transistor formation layer.

[0009] According to another aspect of the present disclosure, an in-cell touch display device may include a plurality of sub-pixels each having a light-emitting element and a thin film transistor, and a plurality of touch electrodes formed in a transistor formation layer in which the thin film transistor is formed, the touch electrodes forming a coupling capacitor with a cathode electrode of the light-emitting element, the cathode electrode including a display panel disposed on the plurality of touch electrodes, and a sensor circuit configured to linearly integrate a signal output from the touch electrode and quadratically integrate the integrated signal to sense a touch signal. [Effects of the Invention]

[0010] According to the embodiment of the present disclosure, the touch electrode is formed during the backplane process of the thin film transistor, so that the touch function can be realized in the organic light emitting display panel with a minimum number of processes.

[0011] In addition, by disposing the touch electrode within the thin film transistor layer, the touch signal is differentiated twice by the finger capacitor formed between the touch object and the cathode electrode, and the coupling capacitor formed between the cathode electrode and the touch electrode. To address this problem, two integrators are built into the sensor circuit, enabling the touch signal to be detected without error.

[0012] In addition, the thickness of the display panel can be reduced for add-on touch, and the size of the bezel can be reduced.

[0013] In addition, since there is no touch electrode on the organic light emitting element, transmittance can be improved compared to existing touch technologies.

[0014] Furthermore, a transparent electrode is used in the backplane of the thin film transistor to form the touch electrode, allowing top and bottom emission of the organic light emitting element.

[0015] In addition, since the touch electrodes are located within the backplane of the thin film transistors, double-sided touch is possible.

[0016] Furthermore, it is possible to reduce touch costs and production energy and achieve process optimization.

[0017] Furthermore, since there is no need to satisfy a large parasitic capacitance between the touch electrode and the display electrode, power consumption can be reduced, and low power consumption can be achieved.

[0018] The above-mentioned effects and specific effects of the present invention will be described in conjunction with the following description of the preferred embodiment of the invention. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 1 illustrates an in-cell touch display device according to one embodiment of the present disclosure. [Figure 2] FIG. 2 illustrates a timing diagram for an in-cell touch display device according to one embodiment of the present disclosure. [Figure 3a]3A and 3B are diagrams illustrating a sensor circuit and a touch drive state of the touch drive circuit according to the first embodiment of the present disclosure. [Figure 3b] 3A and 3B are diagrams illustrating a sensor circuit and a touch drive state of the touch drive circuit according to the first embodiment of the present disclosure. [Figure 4a] FIG. 10 is a diagram illustrating a sensor circuit and a touch drive state of a touch drive circuit according to a second embodiment of the present disclosure. [Figure 4b] FIG. 10 is a diagram illustrating a sensor circuit and a touch drive state of a touch drive circuit according to a second embodiment of the present disclosure. [Figure 5a] 10A and 10B are diagrams illustrating an equivalent circuit of a touch drive circuit and a touch drive state according to a second embodiment of the present disclosure. [Figure 5b] 10A and 10B are diagrams illustrating an equivalent circuit of a touch drive circuit and a touch drive state according to a second embodiment of the present disclosure. [Figure 6a] FIG. 10 is a diagram showing voltage characteristics depending on an RLC parallel circuit and τ and ωd values. [Figure 6b] FIG. 10 is a diagram showing voltage characteristics depending on an RLC parallel circuit and τ and ωd values. [Figure 7a] 1 is a diagram showing an RLC parallel circuit to which a modulation voltage is applied and voltage characteristics resulting from the application of the modulation voltage; [Figure 7b] 1 is a diagram showing an RLC parallel circuit to which a modulation voltage is applied and voltage characteristics resulting from the application of the modulation voltage; [Figure 8] FIG. 1 is a diagram illustrating a power supply modulation circuit applied to an in-cell touch display device according to an embodiment of the present disclosure. [Figure 9] 1 is a cross-sectional view of a display panel in an in-cell touch display device according to an embodiment of the present disclosure. [Figure 10] FIG. 1 is a simplified diagram illustrating a touch sensor structure of an in-cell touch display device according to an embodiment of the present disclosure. [Figure 11] 1 is a cross-sectional view of a display panel in an in-cell touch display device according to an embodiment of the present disclosure. [Figure 12] FIG. 2 illustrates a sensor circuit in an in-cell touch display device according to one embodiment of the present disclosure. [Figure 13]1A and 1B are diagrams illustrating driving states of an in-cell touch display device according to an embodiment of the present disclosure. [Figure 14] FIG. 10 is a diagram showing a driving timing diagram of an in-cell touch display device according to an embodiment of the present disclosure. [Figure 15] FIG. 2 is a diagram illustrating a display panel in an in-cell touch display device according to an embodiment of the present disclosure. [Figure 16] FIG. 16 is an equivalent circuit diagram of the touch unit of FIG. [Figure 17] 16 is a diagram showing output values of the touch electrodes according to the touch positions in FIG. 15. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0020] The advantages and features of the present specification, as well as methods for achieving them, will become clearer with reference to the following detailed embodiments in conjunction with the accompanying drawings. However, the present specification is not limited to the embodiments disclosed below, and may be embodied in various different forms. However, the present embodiments are provided to complete the disclosure of the specification and to fully convey the scope of the invention to those skilled in the art to which the specification pertains, and the specification is defined only by the scope of the claims.

[0021] The shapes, sizes, ratios, angles, numbers, etc. disclosed in the drawings for explaining the embodiments of this specification are illustrative only, and the specification is not limited to the illustrated matters. The same reference symbols throughout the specification refer to the same components. Furthermore, in explaining this specification, if a detailed description of related publicly known technology is deemed to obscure the gist of this specification, such a detailed description will be omitted. When using words such as "include," "have," and "be," other parts can be added unless "only" is used. When a component is expressed in the singular, it also includes the plural unless otherwise explicitly stated.

[0022] When interpreting elements, they are interpreted as including a margin of error, even if there is no explicit statement otherwise.

[0023] When describing temporal relationships, for example, when describing temporal precedence using "after," "following," "next to," or "before," it is acceptable to include cases where things are not consecutive, unless "immediately" or "directly" is used.

[0024] When describing signal flow relationships, for example, if we say "a signal is transmitted from node A to node B," this may also include cases where the signal is transmitted from node A to node B via another node, as long as "immediately" or "directly" is not used.

[0025] Although terms such as "first," "second," and the like are used to describe various components, these components are not limited by these terms. These terms are used merely to distinguish one component from another. Therefore, a first component referred to below may be a second component within the technical concept of this specification.

[0026] The features of the multiple embodiments of this specification can be partially or wholly combined or combined with each other, and various technical interlocking and driving mechanisms are possible, and each embodiment can be implemented independently of each other or can be implemented together in a linked relationship.

[0027] Hereinafter, some embodiments of an in-cell touch display device that can improve touch sensitivity and touch recognition accuracy will be described.

[0028] 1 shows an in-cell touch display device according to one embodiment of the present disclosure, and FIG. 2 shows a timing diagram of the in-cell touch display device according to one embodiment of the present disclosure.

[0029] Referring to FIGS. 1 and 2, the in-cell touch display device may include a display panel 100, a power supply circuit 200, a power supply modulation circuit 400, a source driver (SDIC), a gate driver (GDIC), a touch drive circuit (ROIC), and a controller 300.

[0030] The display panel 100 may include a plurality of sub-pixels (SP) and a plurality of touch electrodes (TE), and can be time-division driven into a display period (Td) and a touch period (Tt). The plurality of touch electrodes (TE) are arranged within a pixel array to sense touch input.

[0031] During the display period (Td), a data voltage corresponding to a video signal may be written to the pixel array of the display panel 100, and during the touch sensor drive period (Tt), the touch electrode (TE) of the display panel 100 may be driven to sense touch input.

[0032] The power supply circuit 200 may include a first power supply circuit 210 and a second power supply circuit 220 .

[0033] The first power supply circuit 210 can generate a high potential power supply voltage (Vdd) and a low potential power supply voltage (Vss) based on an input power supply (VIN) and a ground power supply (GND), and supply them to the first RLC circuit (Rmod1, Lmod1, Cmod1) and the second RLC circuit (Rmod2, Lmod2, Cmod2) of the power supply modulation circuit 400, respectively.

[0034] The second power supply circuit 220 can generate a first modulation control voltage (Vmod1) and a second modulation control voltage (Vmod2) used to modulate a high-potential power supply voltage (Vdd) and a low-potential power supply voltage (Vss) based on an input power supply (VIN) and a ground power supply (GND), and supply these to one end of a first capacitor (Cmod1) of the first RLC circuit and one end of a second capacitor (Cmod2) of the second RLC circuit, respectively.

[0035] The second power supply circuit 220 can supply a first modulation control voltage (Vmod1) at the level of the high potential power supply voltage (Vdd) during the display period and can supply a second modulation control voltage (Vmod2) at the level of the low potential power supply voltage (Vss).

[0036] In addition, the second power supply circuit 220 can supply the first modulation control voltage (Vmod1) at a level having a constant period and amplitude based on the level of the high potential power supply voltage (Vdd) during the touch period, and can supply the second modulation control voltage (Vmod2) at a level having a constant period and amplitude based on the level of the low potential power supply voltage (Vss).

[0037] In addition, the second power supply circuit 220 can generate a high potential gate driving voltage (Vgh) and a low potential gate driving voltage (Vgl) based on the input power supply (VIN) and the ground power supply (GND) during the display period and supply them to the gate driver (GDIC).

[0038] Furthermore, the second power supply circuit 220 can supply a gamma voltage (Vgamma) to the source driver (SDIC) based on the input power supply (VIN) and the ground power supply (GND) during the display period.

[0039] In addition, the second power supply circuit 220 can convert the high potential gate driving voltage (Vgh) into a level having a constant period and amplitude based on the high potential gate driving voltage (Vgh) during the touch period, and convert the low potential gate driving voltage (Vgl) into a level having a constant period and amplitude based on the low potential gate driving voltage (Vgl) and supply them to the gate driver (GDIC).

[0040] In addition, the second power supply circuit 220 may supply a touch driving voltage (Vtouch) having a constant period and amplitude to a touch driving circuit (ROIC) that senses a change in capacitance of the touch electrode (TE) during the touch period.

[0041] In addition, the second power supply circuit 220 can convert the gamma voltage (Vgamma) into a level having a constant period and amplitude based on the gamma voltage (Vgamma) and supply the modulated gamma voltage to the source driver (SDIC).

[0042] The power supply modulation circuit 400 may include a first RLC circuit (Rmod1, Lmod1, Cmod1) in which a resistor, an inductor, and a capacitor are connected in parallel to a high potential power supply line (PL1) through which a high potential power supply voltage (Vdd) is supplied to the display panel 100, and a second RLC circuit (Rmod2, Lmod2, Cmod2) in which a resistor, an inductor, and a capacitor are connected in parallel to a low potential power supply line (PL2) through which a low potential power supply voltage (Vss) is supplied to the display panel 100.

[0043] During the touch period, the power supply modulation circuit 400 can modulate the high potential power supply voltage (Vdd) and the low potential power supply voltage (Vss) into a high potential modulation voltage (Vdd_mod) and a low potential modulation voltage (Vss_mod) having the resonant frequency of a resistor, an inductor, and a capacitor, and supply them to multiple sub-pixels (SP) of the display panel 100.

[0044] The first RLC circuit (Rmod1, Lmod1, Cmod1) can receive a first modulated control voltage (Vmod1) having a constant period and amplitude through one end of a first capacitor (Cmod1) during a touch period, and the second RLC circuit (Rmod2, Lmod2, Cmod2) can receive a second modulated control voltage (Vmod2) having a constant period and amplitude through one end of a second capacitor (Cmod2) during a touch period.

[0045] Here, the first modulation control voltage (Vmod1) may be applied to the level of the high potential power supply voltage (Vdd) during the display period, and the second modulation control voltage (Vmod2) may be applied to the level of the low potential power supply voltage (Vss).

[0046] In addition, the first modulation control voltage (Vmod1) can be applied at a level having a constant period and amplitude based on the level of the high potential power supply voltage (Vdd) during the touch period, and the second modulation control voltage (Vmod2) can be applied at a level having a constant period and amplitude based on the level of the low potential power supply voltage (Vss).

[0047] The first RLC circuit (Rmod1, Lmod1, Cmod1) may include a first resistor (Rmod1) having one end connected to the output terminal of the high potential power supply voltage (Vdd) and the other end connected to the drive transistor (DT) of the sub-pixel (SP), a first inductor (Lmod1) having one end connected to the output terminal of the high potential power supply voltage (Vdd) and the other end connected to the drive transistor (DT) of the sub-pixel (SP), and a first capacitor (Cmod1) having one end connected to the output terminal of the first modulation control voltage (Vmod1) and the other end connected to the drive transistor (DT) of the sub-pixel (SP).

[0048] The second RLC circuit (Rmod2, Lmod2, Cmod2) may include a second resistor (Rmod2) having one end connected to the output terminal of the low potential power supply voltage (Vss) and the other end connected to the light emitting element (OLED) of the sub-pixel (SP), a second inductor (Lmod2) having one end connected to the output terminal of the low potential power supply voltage (Vss) and the other end connected to the light emitting element (OLED) of the sub-pixel (SP), and a second capacitor (Cmod2) having one end connected to the output terminal of the second modulation control voltage (Vmod2) and the other end connected to the light emitting element (OLED) of the sub-pixel (SP).

[0049] The power supply modulation circuit 400 may further include a first dividing resistor (R1) having one end connected to the first power supply line (PL1) and the other end connected to the output terminal of the reference voltage (Vref), and a second dividing resistor (R2) having one end connected to the second power supply line (PL2) and the other end connected to the output terminal of the reference voltage (Vref).

[0050] A node between the first distribution resistor (R1) and the second distribution resistor (R2) is an output terminal of a reference voltage (Vref), and the output terminal of the reference voltage (Vref) may be connected to an input terminal of a reference voltage (Vref) of a touch drive circuit (ROIC) that senses a change in capacitance of the touch electrode (TE).

[0051] Here, the reference voltage (Vref) can be modulated to a level having the same period and amplitude as the high potential modulation voltage (Vdd_mod) and the low potential modulation voltage (Vss_mod) modulated by the first RLC circuit (Rmod1, Lmod1, Cmod1) and the second RLC circuit (Rmod2, Lmod2, Cmod2) during the touch period.

[0052] The source driver (SDIC) can convert input video data using a gamma voltage (Vgamma) into a corresponding data voltage, and can supply the data voltage to the source electrode of the scan transistor (T1) of the subpixel (SP) via the data line (or data wiring) of the display panel 100.

[0053] The gate driver (GDIC) can generate a scan signal using a high-potential gate driving voltage (Vgh) and a low-potential gate driving voltage (Vgl), and can supply the scan signal to the gate electrode of the scan transistor (T1) of the subpixel (SP) via the gate line of the display panel 100.

[0054] The touch drive circuit (ROIC) can use the touch drive voltage (Vtouch) to generate a touch drive signal having the same period and amplitude as the high potential modulation voltage (Vdd_mod) and the low potential modulation voltage (Vss_mod), and can supply the touch drive signal to multiple touch electrodes (TE) of the display panel 100.

[0055] In addition, the touch drive circuit (ROIC) can sense a change in capacitance of the touch electrode (TE), convert the sensed voltage into sensing data (DA_sen), which is a digital signal, and provide the sensing data (DA_sen) to the controller 300.

[0056] The controller 300 can use the touch control signal (TCS) to control the operation timing of the second power supply circuit 220, the gate driver (GDIC), the source driver (SDIC), and the touch drive circuit (ROIC).

[0057] 3a and 3b show the sensor circuit and touch drive states of the touch drive circuit according to the first embodiment of the present disclosure.

[0058] In the case of in-cell touch technology, in which the touch electrode (TE) is designed directly on the backplane of the thin film transistor of the organic light-emitting display panel, the distance between the touch electrode (TE) and the display electrode (DE) is relatively short, which makes the parasitic capacitance between the two electrodes very large.

[0059] In the case of add-on, the distance between the touch electrode (TE) and the display electrode (DE) is approximately 500 μm, proportional to the thickness of the substrate of the touch electrode (TE). On the other hand, in the case of in-cell touch, the distance between the touch electrode and the display electrode is very small, about 5 μm, which increases the parasitic capacitance of the parasitic capacitor (Cp) and reduces touch performance.

[0060] Here, the display electrodes (DE) can be defined as electrodes and wiring for driving the display in the display panel 100.

[0061] As shown in FIGS. 3a and 3b, when the reference voltage (Vref) is modulated to sense the charge on the touch electrode (TE), the amount of charge stored in the feedback capacitor (Cfb) may be (Cp+Cf)*Vref.

[0062] At this time, since the amount of charge stored in the feedback capacitor Cfb is limited, the amount of charge that can be stored in the feedback capacitor Cfb decreases relatively due to an increase in the parasitic capacitance of the parasitic capacitor Cp, resulting in a decrease in touch performance.

[0063] When designing an in-cell touch in an organic light-emitting display panel, the parasitic capacitance of the touch electrode (TE) can become very large, degrading touch performance, and power consumption can increase due to the need to satisfy such a large parasitic capacitance. Furthermore, the touch electrode driving voltage can distort the display signal through a coupling capacitor with the adjacent display electrode, degrading image quality. Furthermore, when display and touch are driven simultaneously, the parasitic capacitance can affect the display electrode (DE) and touch electrode (TE), degrading image quality and touch performance simultaneously.

[0064] The present disclosure aims to provide an in-cell touch display device that can improve touch sensitivity and touch recognition accuracy even when in-cell touch sensor technology is applied to an organic light emitting display panel.

[0065] 4a and 4b show the sensor circuit and touch drive states of the touch drive circuit according to the second embodiment of the present disclosure.

[0066] Referring to Figures 4a and 4b, when driving voltages having the same period and amplitude are applied to the touch electrode (TE) and the display electrode (DE), there is no voltage difference between both ends of the electrodes of the parasitic capacitor (Cp), so the amount of charge charged to the parasitic capacitor (Cp) remains unchanged.

[0067] On the other hand, in the case of the finger capacitor (Cf) between the finger (FIN) and the touch electrode (TE), one side is in a ground (GND) state and the other side has a drive voltage applied, so the amount of charge stored in the finger capacitor (Cf) is proportional to the drive voltage.

[0068] 5a and 5b show an equivalent circuit and touch driving states of a touch driving circuit according to a second embodiment of the present disclosure.

[0069] Referring to Figures 5a and 5b, since the voltages are relative, the input terminals of the touch electrode (TE), display electrode (DE) and reference voltage (Vref) are considered to be equivalent to a DC state in which a pulse-like driving voltage is applied only to the ground electrode of the finger (FIN).

[0070] At this time, the amount of sensed charge can be expressed as a multiplication of the driving voltage generated by the finger (FIN) and the capacitance of the finger capacitor (Cf).

[0071] Therefore, as described above, when the touch electrode (TE), display electrode (DE), and reference voltage (Vref) input terminals are driven with driving signals having the same period and amplitude, only the charge stored in the finger capacitor (Cf) is read regardless of the parasitic capacitance of the parasitic capacitor (Cp), thereby improving touch performance.

[0072] Furthermore, returning to the description of FIGS. 1 and 2, the in-cell touch display device according to an embodiment of the present disclosure can generate modulation voltages having the same period and amplitude on the display electrode and the touch electrode.

[0073] In the case of an organic light emitting display panel, the voltages are divided into a high potential power supply voltage (Vdd) and a low potential power supply voltage (Vss) for supplying current, a gate voltage (or scan pulse), and a data voltage.

[0074] The power supply circuit 200 can generate a high potential power supply voltage (Vdd) and a low potential power supply voltage (Vss) based on an input power supply (VIN) and a ground power supply (GND), and provide them to a first RLC circuit (Rmod1, Lmod1, Cmod1) and a second RLC circuit (Rmod2, Lmod2, Cmod2) of the power supply modulation circuit 400.

[0075] Furthermore, the power supply circuit 200 can generate a first modulation control voltage (Vmod1) and a second modulation control voltage (Vmod2) used to modulate a high-potential power supply voltage (Vdd) and a low-potential power supply voltage (Vss) based on an input power supply (VIN) and a ground power supply (GND), and provide the voltages to one end of a first capacitor (Cmod1) of the first RLC circuit and a second capacitor (Cmod2) of the second RLC circuit.

[0076] In addition, the power supply circuit 200 can provide a high potential gate driving voltage (Vgh) and a low potential gate driving voltage (Vgl) to the gate driver (GDIC) during the display period, and can provide a gamma voltage (Vgamma) to the source driver (SDIC).

[0077] In addition, the power supply circuit 200 can convert the high potential gate driving voltage (Vgh) and the low potential gate driving voltage (Vgl) into levels having a constant period and amplitude during the touch period and provide them to the gate driver (GDIC).

[0078] The power supply circuit 200 may also provide a touch driving voltage (Vtouch) having a constant cycle and amplitude to the touch driving circuit (ROIC) during a touch period, and may convert a gamma voltage (Vgamma) into a level having a constant cycle and amplitude and provide the converted voltage to the source driver (SDIC).

[0079] The power supply modulation circuit 400 can modulate the high potential power supply voltage (Vdd) and low potential power supply voltage (Vss) output from the power supply circuit 200 into a high potential modulation voltage (Vdd_mod) and a low potential modulation voltage (Vss_mod) using a first RLC circuit (Rmod1, Lmod1, Cmod1) and a second RLC circuit (Rmod2, Lmod2, Cmod2).

[0080] These power supply modulation circuits 400 can modulate the high potential power supply voltage (Vdd) and the low potential power supply voltage (Vss) into high potential modulation voltage (Vdd_mod) and low potential modulation voltage (Vss_mod) having the same period and amplitude as the touch drive voltage (Vtouch) during the touch period and provide them to multiple sub-pixels.

[0081] In addition, the power supply modulation circuit 400 can provide modulated display voltages to the gate driver (GDIC) and the source driver (SDIC) based on the high potential modulation voltage (Vdd_mod) and the low potential modulation voltage (Vss_mod), which have the same period and amplitude as the touch driving voltage (Vtouch).

[0082] In addition, the power supply modulation circuit 400 can provide a modulated reference voltage to the touch drive circuit (ROIC) based on the high potential modulation voltage (Vdd_mod) and the low potential modulation voltage (Vss_mod), which has the same period and amplitude as the touch drive voltage (Vtouch).

[0083] Figures 6a and 6b show the RLC parallel circuit and its voltage characteristics depending on the τ and ωd values. Figures 7a and 7b show the RLC parallel circuit to which a modulation voltage is applied and its voltage characteristics depending on the application of the modulation voltage.

[0084] Referring to FIGS. 6a and 6b, when the RLC parallel circuit is switched on, the voltage applied to the circuit is expressed by the following equation (1).

[0085]

number

[0086] At this time, the voltage characteristics at τ=1 and ωd=50 kHz are as shown in FIG. 6b.

[0087] Under the above conditions, if five modulation control voltage pulses are applied in the start section as shown in Figures 7a and 7b, a waveform like that shown in Figure 7b can be obtained. When τ is large and ωd is small, the applied modulation control voltage (Vmod) is output on the high potential power supply voltage (Vdd).

[0088] FIG. 8 illustrates a power supply modulation circuit applied to an in-cell touch display device according to an embodiment of the present disclosure.

[0089] Referring to FIG. 8, if the high potential power supply voltage (Vdd) and the low potential power supply voltage (Vss) are designed with resistors (Rmod1, Rmod2), inductors (Lmod1, Lmod2), and capacitors (Cmod1, Cmod2) having the same values and modulation control voltages (Vmod1, Vmod2) of the same values are applied, the voltage difference between nodes A and B can be maintained constant at all times.

[0090] That is, a high potential power supply voltage (Vdd) and a low potential power supply voltage (Vss) are applied to the load terminal of the display panel 100, and the flowing current can be maintained constant regardless of the modulation control voltages (Vmod1, Vmod2).

[0091] Furthermore, when the modulation control voltages (Vmod1, Vmod2) are generated and applied based on the high potential power supply voltage (Vdd) and the low potential power supply voltage (Vss), respectively, the harmonic components of the high potential modulation voltage (Vdd_mod) and the low potential modulation voltage (Vss_mod) can be significantly reduced.

[0092] According to an embodiment of the present disclosure, when in-cell touch sensor technology is applied to a display panel, the formation of parasitic capacitance between the touch electrode and the display electrode can be prevented, thereby improving touch sensitivity and touch recognition accuracy.

[0093] In addition, the thickness of the display panel can be reduced, and deterioration of image quality due to crosstalk with the touch voltage can be improved.

[0094] Also, touch sensitivity is improved, making it easier to generate uplink signals and enabling active pen touch.

[0095] Furthermore, since the frequency and attenuation constant can be adjusted by changing the resistance value, the inductor can be configured without being large.

[0096] An in-cell touch display device according to one aspect of the present disclosure enables in-cell touch sensor technology to be implemented in an organic light emitting display panel.

[0097] FIG. 9 illustrates a cross-sectional view of a display panel in an in-cell touch display device according to one embodiment of the present disclosure.

[0098] Referring to FIG. 9, the display panel 100 of the in-cell touch display device according to one aspect of the present disclosure may include a substrate (SUB), a transistor forming layer (TRL), light emitting element layers (AE, EL, CE), and a cover layer (CL).

[0099] A transistor formation layer (TRL) may be formed on the substrate (SUB).

[0100] The transistor formation layer (TRL) may include a cathode electrode (CE) of the light emitting element layer and a plurality of touch electrodes (TE) forming a coupling capacitor (Cct). The plurality of touch electrodes (TE) may be formed of transparent electrodes and may be formed on the substrate (SUB) at regular intervals. Alternatively, the touch electrodes (TE) may be formed in the same layer as the metal of the transistor formation layer (TRL), with the same material and by the same process as the metal of the transistor formation layer (TRL).

[0101] The light emitting element layers (AE, EL, CE) may be formed on the transistor formation layer (TRL).

[0102] The light-emitting element layer (AE, EL, CE) may include an anode electrode (AE), a light-emitting layer (EL), and a cathode electrode (CE). The anode electrode (AE) may be formed on the transistor formation layer (TRL) at a certain interval. The light-emitting layer (EL) may be formed between the anode electrode (AE) and the cathode electrode (CE). The light-emitting layer (EL) may be made of an organic material. The cathode electrode (CE) may be formed on the light-emitting layer (EL).

[0103] A cover layer (CL) may be formed on the light-emitting element layers (AE, EL, CE). When a touch object (FIN) touches the cover layer (CL), a capacitor (Cf) may be formed between the touch object (FIN) and the cathode electrode. In this specification, the capacitor (Cf) between the touch object (FIN) and the cathode electrode is referred to as an object capacitor (Cf) or a finger capacitor (Cf). A capacitor (Cct) may also be formed between the cathode electrode (CE) and the touch electrode (TE). In this specification, the capacitor (Cct) formed between the cathode electrode (CE) and the touch electrode (TE) is referred to as a coupling capacitor (Cct). Forming the finger capacitor (Cf) and the coupling capacitor (Cct) in the display panel 100 enables a touch to be sensed regardless of the position of the touch on the display panel.

[0104] The anode electrode (AE) between the touch electrode (TE) and the cathode electrode (CE) is considered to be a floating electrode because the resistance of the driving thin film transistor becomes very large when expressing low gradations, so the capacitance value of the coupling capacitor (Cct) can be maintained as it is.

[0105] In addition, when expressing high gradations, the anode electrode (AE) between the touch electrode (TE) and the cathode electrode (CE) reduces the resistance of the driving thin film transistor, and forms a series capacitor with the capacitor between the cathode electrode (CE) and the anode electrode (AE) and the driving thin film transistor and the gate-source capacitor of the driving thin film transistor, so the effect on the coupling capacitor (Cct) can be very small.

[0106] Therefore, when an object touches the display panel 100, the change in capacitance of the finger capacitor Cf and the coupling capacitor Cct formed in the display panel 100 is sensed, thereby detecting the touch.

[0107] FIG. 10 shows a simplified touch sensor structure of an in-cell touch display device according to one embodiment of the present disclosure.

[0108] Referring to FIG. 10, the touch sensor of the display panel 100 may include a touch electrode (TE) and a touch wiring (TL).

[0109] The cathode electrode (CE) may be formed on the entire surface of the display area of the display panel 100.

[0110] A plurality of touch electrodes (TE) may be arranged in a grid pattern in the display area.

[0111] The touch wiring (TL) may be electrically connected to each touch electrode (TE), and a signal from each touch electrode (TE) may be transmitted to an external sensor circuit via the touch wiring (TL).

[0112] FIG. 11 shows a cross-sectional view of a display panel in an in-cell touch display device according to one embodiment of the present disclosure.

[0113] Referring to FIG. 11, the display panel 100 may include a substrate (SUB), a transistor formation layer (TRL) in which a thin film transistor (TFT) and a touch electrode (TE) are formed, light emitting element layers (AE, EL, CE), and a cover layer (CL).

[0114] Touch electrodes (TE) may be formed at regular intervals on the substrate (SUB).

[0115] A buffer layer 111 may be formed on the substrate (SUB) and the touch electrode (TE). The buffer layer 111 may be made of an insulating material.

[0116] On the buffer layer 111, a semiconductor 112 of a thin film transistor (TFT) may be formed.

[0117] A gate insulating layer 113 may be formed on the semiconductor 112 and the buffer layer 111 .

[0118] A gate electrode 114 may be formed on the gate insulating layer 113 at a position overlapping with the semiconductor 112 .

[0119] An interlayer insulating layer 115 may be formed between the gate electrode 114 and the gate insulating layer 113 .

[0120] A source electrode 116 and a drain electrode 117 may be formed on the interlayer insulating layer 115. The source electrode 116 and the drain electrode 117 may be electrically connected to the semiconductor 112 through contact holes.

[0121] In addition, a touch wiring (TL) may be formed on the interlayer insulating layer 115. The touch wiring (TL) may be electrically connected to the touch electrode (TE) through a contact hole.

[0122] In one example, the touch line (TL) may be formed in the same layer as the source electrode 116 and the drain electrode 117. Alternatively, the touch line (TL) may be formed in a different layer from the source electrode 116 and the drain electrode 117 and in a direction parallel to the data line (not shown in FIG. 11 ). A data voltage may be applied to the data line, and the data line may be electrically connected to the gate electrode 114 of the drive transistor via a scan transistor (not shown in FIG. 11 ).

[0123] A first planarization layer 118 may be formed on the source electrode 116, the drain electrode 117, the touch wiring (TL), and the interlayer insulating layer 115.

[0124] A second planarization layer 119 may be formed on the first planarization layer 118 .

[0125] On the other hand, the stacking position of the touch electrode (TE) is merely an example, and the touch electrode (TE) is not limited to being disposed between the substrate (SUB) and the buffer layer 111. For example, the touch electrode (TE) may be disposed in the same layer as the gate electrode 114, or in the same layer as the source electrode 116 and the drain electrode 117. Alternatively, the touch electrode (TE) may be disposed between the first planarization layer 118 and the second planarization layer 119.

[0126] An anode electrode (AE) of the organic light emitting element may be formed on the second planarization layer 119. The anode electrode (AE) may be electrically connected to the drain electrode 117 of the thin film transistor (TFT) through a pixel contact hole.

[0127] Furthermore, a bank layer 120 may be formed on a part of the second planarization layer 119 and a part of the anode electrode (AE). The bank layer 120 may be made of an opaque material to prevent optical interference between adjacent pixels.

[0128] An emitting layer (EL) may be formed on the anode electrode (AE). The emitting layer (EL) may be made of an organic luminescent material.

[0129] A cathode electrode (CE) may be formed on the light-emitting layer (EL).

[0130] A cover layer (CL) may be formed on the cathode electrode (CE). The cover layer (CL) may be made of a transparent material.

[0131] In the in-cell touch display device according to the present disclosure, during a touch period, a touch drive signal having a constant period and amplitude may be applied to the touch electrode (TE), and a low-potential modulation voltage (Vss_mod, FIG. 1) having the same period and amplitude as the touch drive signal may be applied to the cathode electrode (CE).

[0132] The touch electrode (TE) can form a coupling capacitor (Cct) with the cathode electrode (CE). Forming the coupling capacitor (Cct) between the touch electrode (TE) and the cathode electrode (CE) enables touch sensing regardless of the touch position.

[0133] The anode electrode (AE) between the touch electrode (TE) and the cathode electrode (CE) is considered to be a floating electrode because the resistance of the driving thin film transistor becomes very large when expressing low gradations, so the capacitance value of the coupling capacitor (Cct) can be maintained as it is.

[0134] In addition, the anode electrode (AE) between the touch electrode (TE) and the cathode electrode (CE) reduces the resistance of the driving thin film transistor when expressing high gray scales, and forms a series capacitor with the capacitor between the cathode electrode (CE) and the anode electrode (AE) and the driving thin film transistor and the gate-source capacitor of the driving thin film transistor, so that the effect on the coupling capacitor (Cct) can be significantly reduced, thereby enabling touch sensing.

[0135] The in-cell touch display device can be time-division driven into a display period and a touch period, and the touch driving signal in the touch period can have a constant period and amplitude.

[0136] In one example, during a touch period, the high potential power supply voltage (Vdd) and the low potential power supply voltage (Vss) can be modulated into a high potential modulation voltage (Vdd_mod) and a low potential modulation voltage (Vss_mod) having the same period and amplitude as the touch drive voltage and supplied to multiple sub-pixels.

[0137] In addition, the display voltages (e.g., gamma voltage, gate high potential voltage, and gate low potential voltage) can be modulated to voltages having the same period and amplitude as the touch drive voltage based on the high potential modulation voltage (Vdd_mod) and the low potential modulation voltage (Vss_mod).

[0138] In addition, the reference voltage (Vref) can be modulated to a voltage having the same period and amplitude as the touch drive voltage based on the high potential modulation voltage (Vdd_mod) and the low potential modulation voltage (Vss_mod).

[0139] As shown in FIGS. 9 to 11, a touch electrode (TE) and a thin film transistor (TFT) are formed on a substrate (SUB), and light emitting element layers (AE, EL, CE) are deposited thereon. When an object (FIN) is touched, a touch signal can be transmitted to a touch wiring (TL) through an object capacitor (Cf) and a coupling capacitor (Cct).

[0140] At this time, the touch signal passes through the object capacitor (Cf) and the coupling capacitor (Cct) twice, and the original signal is differentiated twice. In the in-cell touch display device according to the present disclosure, the sensor circuit for detecting the touch signal incorporates two integrators to integrate the touch signal twice and detect the touch signal. Here, the sensor circuit is a readout circuit and may be included in the touch drive circuit (ROIC, shown in FIG. 1).

[0141] FIG. 12 illustrates a sensor circuit in an in-cell touch display device according to one embodiment of the present disclosure.

[0142] Referring to FIG. 12, the sensor circuit 500 first integrates the signal output from the touch electrode (TE) and then second-order integrates the integrated signal to sense the touch signal.

[0143] The sensor circuit 500 may include a first integrator 510 that linearly integrates the signal output from the touch electrode (TE), and a second integrator 520 that quadratically integrates the signal integrated by the first integrator 510.

[0144] The first integrator 510 may include a first operational amplifier (AMP) having a first input terminal that receives the output signal of the touch electrode (TE) and a second input terminal to which a reference voltage (Vref) is applied, and a first feedback capacitor (Cfb1) that is coupled between the first input terminal and the output terminal of the first operational amplifier (AMP).

[0145] The second integrator 520 may include a second operational amplifier (AMP) having a third input terminal electrically connected to the output terminal of the first operational amplifier (AMP) and a fourth input terminal to which a reference voltage (Vref) is applied, and a second feedback capacitor (Cfb2) connected between the third input terminal and the output terminal of the second operational amplifier (AMP).

[0146] During a touch period, the touch drive signals applied to the touch electrodes (TE) have a constant period and amplitude. These touch drive signals are differentiated twice via the object capacitor (Cf) and the coupling capacitor (Cct). The sensor circuit 500 can recover the touch drive signals by integrating the signals output from the touch electrodes (TE) twice by the first integrator 510 and the second integrator 520.

[0147] FIG. 13 illustrates the driving states of an in-cell touch display device according to an embodiment of the present disclosure.

[0148] 13, during a touch period, a touch drive signal having a constant period and amplitude may be applied to a touch electrode (TE). A low-potential modulation voltage (Vss_mod) having the same period and amplitude as the touch drive signal may be applied to a cathode electrode (CE). A reference voltage (Vref) having the same period and amplitude as the touch drive signal may be applied to the reference voltage input terminals of a first integrator 510 and a second integrator 520.

[0149] FIG. 13 shows the voltage state of the equivalent circuit when touched. Assuming that the signal when touched is modulated by the potential of the touching finger, the sensor system is as follows:

[0150] First, the modulated signal transmitted by the finger passes through the object capacitor (Cf) and is converted into a first-order differential signal. That is, the modulated signal instantaneously crosses the object capacitor (Cf) and then passes through the resistor (Rs). The first-order differential signal is transmitted to the first integrator 510 through the coupling capacitor (Cct), where it is also second-order differentiated and input to the first integrator 510. This signal is integrated through the first integrator 510 and converted into a form similar to the signal output through the object capacitor (Cf). It is then restored to a form similar to the original modulated signal through the second integrator 520. Therefore, the final output value of the sensor circuit 500 is proportional to the magnitude of the touch input signal.

[0151] FIG. 14 shows a driving timing diagram for an in-cell touch display device according to one embodiment of the present disclosure.

[0152] Referring to FIG. 14, (1) shows a case where it is assumed that the finger potential applied to the object capacitor (Cf) is modulated when a touch drive signal having a constant period and amplitude is applied to the touch electrode (TE) during a touch period and a low potential modulation voltage (Vss_mod) having the same period and amplitude as the touch drive signal is applied to the cathode electrode (CE).

[0153] (2) indicates a signal that has been first differentiated through the object capacitor (Cf), and (3) indicates a signal that has been second differentiated through the coupling capacitor (Cct). (4) indicates a signal that has been first integrated by the first integrator 510. Here, the first-order integrated signal is the same as the inverted signal of the first-order differentiated signal. (5) indicates a signal that has been second-order integrated by the second integrator 520. Here, the second-order integrated signal is the same as the restored signal of the signal (1).

[0154] Fig. 15 shows a display panel in an in-cell touch display device according to an embodiment of the present disclosure. Fig. 16 shows an equivalent circuit diagram of the touch unit in Fig. 15. Fig. 17 shows output values of the touch electrodes according to the touch positions in Fig. 15.

[0155] To confirm the operational characteristics, a simulation was performed using a display panel 100 configured as shown in Figure 15. First, the pixel unit includes a sheet resistance (Rs), a parasitic capacitor (Cp), and a resistor (Rol) disposed between the sheet resistance (Rs) supplied with a low potential power supply voltage (Vss) and a high potential power supply voltage (Vdd). Here, the resistor (Rol) functions as a series resistor between the driving thin film transistor and the light emitting element.

[0156] The touch unit 110 is composed of 5x5 pixel units, and the display panel 100 is composed of 4x5 touch units 110. A low potential power supply voltage (Vss) is supplied to the outer periphery of the display panel 100 via a low potential power supply voltage wiring. The sizes of the resistance (Rol) and parasitic capacitor (Cp) are set to be equivalent to the values of 20 touch units 110 in the display panel.

[0157] As an example, the result value obtained for one pulse under the conditions of sheet resistance 87Ω / sh, touch wiring resistance 500Ω, object capacitor (Cf) 1pF, and modulation control voltage (Vmod) 10V is shown in Figure 17. The touch drive signal applied by the modulation control voltage pulse is not widely spread due to the sheet resistance of the panel, but is output in three to four areas of the touch electrode (TE), allowing the touch position to be determined.

[0158] As described above, according to the embodiment of the present disclosure, the touch electrode is formed during the backplane process of the thin film transistor, so that the touch function can be implemented in the organic light emitting display panel with a minimum number of processes.

[0159] In addition, by arranging a touch electrode in the transistor formation layer, a finger capacitor formed between the touch object and the cathode electrode, and a coupling capacitor formed between the cathode electrode and the touch electrode, the problem of the touch signal being differentiated twice is addressed by incorporating two integrators into the sensor circuit, which enables the touch signal to be detected without error.

[0160] In addition, the thickness of the display panel can be reduced for add-on touch, and the bezel size can be reduced.

[0161] In addition, since there is no touch electrode on the organic light emitting element, transmittance can be improved compared to existing touch technologies.

[0162] Furthermore, the touch electrode is formed using a transparent electrode in the backplane of the thin film transistor, allowing emission from the top and bottom of the organic light emitting element.

[0163] In addition, since the touch electrodes are located within the backplane of the thin film transistors, double-sided touch is possible.

[0164] In addition, it is possible to reduce touch costs and production energy and realize process optimization.

[0165] Furthermore, since there is no need to satisfy a large parasitic capacitance between the touch electrode and the display electrode, power consumption can be reduced, and low power consumption can be realized.

[0166] An in-cell touch display device according to one aspect of the present disclosure may include a substrate, a transistor formation layer formed on the substrate and including a semiconductor, a source electrode, a drain electrode, and a gate electrode, and a light-emitting element layer formed on the transistor formation layer and including an anode electrode, a light-emitting layer, and a cathode electrode, and a plurality of touch electrodes forming a coupling capacitor with the cathode electrode of the light-emitting element layer may be formed in the transistor formation layer.

[0167] According to one aspect of the present disclosure, a cover layer may be further formed on the light-emitting element layer, and when the touch object touches the cover layer, an object capacitor may be formed between the touch object and the cathode electrode.

[0168] According to one aspect of the present disclosure, the touch panel may further include a sensor circuit that senses a change in capacitance of the object capacitor and the coupling capacitor via the touch electrode when a touch object touches the cover layer.

[0169] According to one aspect of the present disclosure, the touch electrode may be formed on the substrate in a transistor-forming layer.

[0170] According to one aspect of the present disclosure, the touch electrode may be disposed in the same layer as the gate electrode or the same layer as the source electrode and the drain electrode.

[0171] According to an aspect of the present disclosure, the display device may further include a touch wiring formed in the transistor formation layer and electrically connected to the touch electrode.

[0172] According to one aspect of the present disclosure, the touch wiring may be formed in the same layer as the source electrode and the drain electrode of the transistor formation layer.

[0173] According to one aspect of the present disclosure, the touch wiring may be formed in a layer different from that of the source electrode and the drain electrode in the transistor formation layer, and in a direction parallel to the data wiring.

[0174] According to one aspect of the present disclosure, during a touch period, a touch drive signal having a constant period and amplitude may be applied to the touch electrode, and a low-potential modulation voltage having the same period and amplitude as the touch drive signal may be applied to the cathode electrode.

[0175] According to one aspect of the present disclosure, the touch electrode may be formed of a transparent electrode.

[0176] According to another aspect of the present disclosure, an in-cell touch display device may include a plurality of sub-pixels each having a light-emitting element and a thin film transistor, and a plurality of touch electrodes formed in a transistor formation layer in which the thin film transistor is formed, the touch electrodes forming a coupling capacitor with a cathode electrode of the light-emitting element, the cathode electrode including a display panel disposed on the plurality of touch electrodes, and a sensor circuit for first-order integration of a signal output from the touch electrode and second-order integration of the integrated signal to sense the touch signal.

[0177] According to another aspect of the present disclosure, the sensor circuit may include a first integrator that linearly integrates a signal output from the touch electrode, and a second integrator that quadratically integrates the signal integrated by the first integrator.

[0178] According to another aspect of the present disclosure, the first integrator may include a first operational amplifier having a first input terminal that receives the output signal of the touch electrode and a second input terminal to which a reference voltage is applied, and a first feedback capacitor coupled between the first input terminal and the output terminal of the first operational amplifier.

[0179] According to another aspect of the present disclosure, the second integrator may include a second operational amplifier having a third input terminal electrically coupled to the output terminal of the first operational amplifier and a fourth input terminal to which a reference voltage is applied, and a second feedback capacitor coupled between the third input terminal and the output terminal of the second operational amplifier.

[0180] According to another aspect of the present disclosure, during a touch period, a touch drive signal having a constant period and amplitude may be applied to the touch electrode, a low-potential modulation voltage having the same period and amplitude as the touch drive signal may be applied to the cathode electrode, and a reference voltage having the same period and amplitude as the touch drive signal may be applied to the second input terminal of the first operational amplifier and the fourth input terminal of the second operational amplifier.

[0181] According to another aspect of the present disclosure, a display panel may include a substrate, a transistor formation layer formed on the substrate and including a semiconductor, a source electrode, a drain electrode, and a gate electrode, and a light-emitting element layer formed on the transistor formation layer and including an anode electrode, a light-emitting layer, and a cathode electrode, and a plurality of touch electrodes may be formed in the transistor formation layer and can form a coupling capacitor with the cathode electrode of the light-emitting element layer.

[0182] According to another aspect of the present disclosure, a cover layer may be further formed on the light-emitting element layer, and when a touch object touches the cover layer, an object capacitor may be formed between the touch object and the cathode electrode.

[0183] According to another aspect of the present disclosure, the sensor circuit can sense, with at least one integrator, a change in capacitance of the object capacitor and the coupling capacitor when a touch object touches the cover layer.

[0184] Although the present invention has been described above with reference to illustrative drawings, it is obvious that the present invention is not limited to the embodiments and drawings disclosed in this specification, and that various modifications can be made by those skilled in the art within the scope of the technical concept of the present invention. Furthermore, even if the effects of the configuration of the present invention are not explicitly described and explained while the embodiments of the present invention are described above, it is natural that the effects that can be predicted by the configuration should also be recognized.

Claims

1. A substrate; a transistor forming layer formed on the substrate and including a semiconductor, a source electrode, a drain electrode, and a gate electrode; a light-emitting element layer formed on the transistor-forming layer and including an anode electrode, a light-emitting layer, and a cathode electrode; Including, A plurality of touch electrodes forming a coupling capacitor with the cathode electrode of the light-emitting element layer are formed in the transistor formation layer. In-cell touch display device.

2. a cover layer is further formed on the light emitting device layer; When a touch object touches the cover layer, an object capacitor is formed between the touch object and the cathode electrode. The in-cell touch display device according to claim 1 .

3. a sensor circuit configured to sense a change in capacitance of the object capacitor and the coupling capacitor via the touch electrode when the touch object touches the cover layer; The in-cell touch display device according to claim 2 .

4. The sensor circuit a first integrator that linearly integrates a signal output from the touch electrode; a second integrator that quadratically integrates the signal integrated by the first integrator; Including, The in-cell touch display device according to claim 3 .

5. The first integrator a first operational amplifier having a first input terminal for receiving the output signal of the touch electrode and a second input terminal for applying a reference voltage; a first feedback capacitor coupled between the first input terminal and the output terminal of the first operational amplifier; Including, The in-cell touch display device according to claim 4 .

6. The second integrator a second operational amplifier having a third input terminal electrically connected to the output terminal of the first operational amplifier and a fourth input terminal to which the reference voltage is applied; a second feedback capacitor coupled between the third input terminal and the output terminal of the second operational amplifier; Including, The in-cell touch display device according to claim 5 .

7. During a touch period, a touch drive signal having a constant period and amplitude is applied to the touch electrode, a low-potential modulation voltage having the same period and amplitude as the touch drive signal is applied to the cathode electrode, and the reference voltage having the same period and amplitude as the touch drive signal is applied to the second input terminal of the first operational amplifier and the fourth input terminal of the second operational amplifier. The in-cell touch display device according to claim 6 .

8. The touch electrode is formed on the substrate in the transistor formation layer, and is disposed in the same layer as the gate electrode or the same layer as the source electrode and the drain electrode, and is formed of a transparent electrode. The in-cell touch display device according to claim 1 .

9. The touch panel further includes a touch wiring formed in the transistor formation layer and electrically connected to the touch electrode. The in-cell touch display device according to claim 1 .

10. The touch wiring is formed in the same layer as the source electrode and the drain electrode of the transistor formation layer. The in-cell touch display device according to claim 9 .

11. The touch wiring is formed in a layer different from the source electrode and the drain electrode of the transistor formation layer and is formed in a direction parallel to the data wiring. The in-cell touch display device according to claim 9 .

12. During a touch period, a touch driving signal having a constant period and amplitude is applied to the touch electrode, and a low-potential modulation voltage having the same period and amplitude as the touch driving signal is applied to the cathode electrode. The in-cell touch display device according to claim 1 .

13. a display panel including a light-emitting element and a plurality of sub-pixels each having a thin film transistor, the display panel including a plurality of touch electrodes formed in a transistor formation layer in which the thin film transistor is formed and forming a coupling capacitor with a cathode electrode of the light-emitting element, the cathode electrode being disposed on the plurality of touch electrodes; a sensor circuit that first integrates a signal output from the touch electrode and then second integrates the integrated signal to sense a touch signal; Including, In-cell touch display device.

14. The sensor circuit a first integrator that linearly integrates a signal output from the touch electrode; a second integrator that second-orderly integrates the signal integrated by the first integrator; Including, The in-cell touch display device according to claim 13 .

15. The first integrator a first operational amplifier having a first input terminal for receiving the output signal of the touch electrode and a second input terminal for applying a reference voltage; a first feedback capacitor coupled between the first input terminal and the output terminal of the first operational amplifier; Including, The in-cell touch display device of claim 14.

16. The second integrator a second operational amplifier having a third input terminal electrically connected to the output terminal of the first operational amplifier and a fourth input terminal to which the reference voltage is applied; a second feedback capacitor coupled between the third input terminal and the output terminal of the second operational amplifier; Including, The in-cell touch display device of claim 15.

17. During a touch period, a touch drive signal having a constant period and amplitude is applied to the touch electrode, a low-potential modulation voltage having the same period and amplitude as the touch drive signal is applied to the cathode electrode, and the reference voltage having the same period and amplitude as the touch drive signal is applied to the second input terminal of the first operational amplifier and the fourth input terminal of the second operational amplifier.

17. The in-cell touch display device of claim 16.

18. The display panel includes: A substrate; a transistor-forming layer formed on the substrate and including a semiconductor, a source electrode, a drain electrode, and a gate electrode; a light-emitting element layer formed on the transistor-forming layer and including an anode electrode, a light-emitting layer, and the cathode electrode; a cover layer formed on the light-emitting element layer, the cover layer being configured to form an object capacitor between the touch object and the cathode electrode when touched by the touch object; Including, The plurality of touch electrodes are formed in the transistor formation layer and form the coupling capacitor with the cathode electrode of the light emitting element layer. The in-cell touch display device according to claim 13 .

19. the sensor circuit senses, by at least one integrator, a change in capacitance of the object capacitor and the coupling capacitor when the touch object touches the cover layer; 19. The in-cell touch display device of claim 18.

20. The touch electrode is formed on the substrate in the transistor formation layer, and is disposed in the same layer as the gate electrode or the same layer as the source electrode and the drain electrode.

19. The in-cell touch display device of claim 18.

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