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 Art

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

[0003] Thus, 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. These methods have the disadvantages of increasing the size and thickness of the device and complicating the manufacturing process. For this reason, in-cell touch sensor technology that includes a touch sensor in the display panel without separately manufacturing the touch panel has been developed.

Summary of the Invention

Problems to be Solved by the Invention

[0004] Designing and manufacturing a display panel including a touch sensor is a technology with a very high technical difficulty. Also, when installing a touch sensor including a plurality of touch electrodes in a display panel, the touch sensor is located very close to the surrounding display driving electrodes and display driving wirings inside the display panel, and the parasitic capacitance between the touch sensor and the display driving electrodes, or the parasitic capacitance between the touch sensor and the display driving wirings, may become very large, and the increase in parasitic capacitance may lead to a decrease in touch sensitivity.

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

[0006] Therefore, the problem that this specification aims to solve is to provide an in-cell touch display device that enables the application of in-cell touch sensor technology to an organic light-emitting display panel.

[0007] The problems to be solved by one embodiment of this specification are not limited to those mentioned above, and other problems not mentioned can 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 layer formed on the transistor formation layer and including an anode electrode, a light-emitting layer, and a cathode electrode, wherein a plurality of touch electrodes forming a coupling capacitor with the cathode electrode of the light-emitting layer may be formed within the transistor formation layer.

[0009] An in-cell touch display device according to another aspect of the present disclosure includes a plurality of subpixels having light-emitting elements and thin-film transistors, and includes a plurality of touch electrodes formed in a transistor formation layer on which the thin-film transistors are formed, forming a cathode electrode of a light-emitting element and a coupling capacitor, wherein the cathode electrode may include a display panel arranged on the plurality of touch electrodes, and a sensor circuit that senses a touch signal by linearly integrating the signal output from the touch electrodes and quadratically integrating the integrated signal. [Effects of the Invention]

[0010] According to embodiments of this disclosure, touch electrodes are formed during the backplane process of a thin-film transistor, thereby enabling the implementation of touch functionality in an organic light-emitting display panel with a minimum number of steps.

[0011] Furthermore, by placing the touch electrode within the thin-film transistor layer, and addressing the problem of the touch signal being 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, two integrators can be incorporated into the sensor circuit to accurately detect the touch signal.

[0012] Furthermore, the thickness of the display panel can be reduced compared to add-on touch, and the bezel size can be reduced.

[0013] Furthermore, because there are no touch electrodes on the organic light-emitting element, the transmittance can be improved compared to existing touch technologies.

[0014] Furthermore, by using transparent electrodes within the backplane of the thin-film transistor to form touch electrodes, it enables top and bottom emission of organic light-emitting elements.

[0015] Furthermore, because the touch electrodes are located within the backplane of the thin-film transistor, it enables double-sided touch.

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

[0017] Furthermore, since it is not necessary to satisfy the large parasitic capacitance between the touch electrode and the display electrode, power consumption can be reduced, making it possible to achieve low power consumption.

[0018] The effects described above, as well as the specific effects of the present invention, will be explained and described below in relation to the embodiments for carrying out the invention. [Brief explanation of the drawing]

[0019] [Figure 1] This figure shows an in-cell touch display device according to one embodiment of the present disclosure. [Figure 2] This figure shows a timing diagram of an in-cell touch display device according to one embodiment of the present disclosure. [Figure 3a]FIG. showing the sensor circuit and touch driving state of the touch driving circuit according to the first embodiment of the present disclosure. [Figure 3b] FIG. showing the sensor circuit and touch driving state of the touch driving circuit according to the first embodiment of the present disclosure. [Figure 4a] FIG. showing the sensor circuit and touch driving state of the touch driving circuit according to the second embodiment of the present disclosure. [Figure 4b] FIG. showing the sensor circuit and touch driving state of the touch driving circuit according to the second embodiment of the present disclosure. [Figure 5a] FIG. showing the equivalent circuit and touch driving state of the touch driving circuit according to the second embodiment of the present disclosure. [Figure 5b] FIG. showing the equivalent circuit and touch driving state of the touch driving circuit according to the second embodiment of the present disclosure. [Figure 6a] FIG. showing the voltage characteristics of the RLC parallel circuit and τ and ωd values. [Figure 6b] FIG. showing the voltage characteristics of the RLC parallel circuit and τ and ωd values. [Figure 7a] FIG. showing the RLC parallel circuit to which the modulation voltage is applied and the voltage characteristics due to the application of the modulation voltage. [Figure 7b] FIG. showing the RLC parallel circuit to which the modulation voltage is applied and the voltage characteristics due to the application of the modulation voltage. [Figure 8] FIG. showing the power supply modulation circuit applied to the in-cell touch display device according to an embodiment of the present disclosure. [Figure 9] Cross-sectional view of the display panel in the in-cell touch display device according to an embodiment of the present disclosure. [Figure 10] FIG. briefly showing the touch sensor structure of the in-cell touch display device according to an embodiment of the present disclosure. [Figure 11] Cross-sectional view of the display panel in the in-cell touch display device according to an embodiment of the present disclosure. [Figure 12] FIG. showing the sensor circuit in the in-cell touch display device according to an embodiment of the present disclosure. [Figure 13]This figure shows the driving state of an in-cell touch display device according to one embodiment of the present disclosure. [Figure 14] This figure shows a drive timing diagram for an in-cell touch display device according to one embodiment of the present disclosure. [Figure 15] This figure shows a display panel in an in-cell touch display device according to one embodiment of the present disclosure. [Figure 16] Figure 15 is an equivalent circuit diagram of the touch unit. [Figure 17] This figure shows the output values ​​of the touch electrodes at different touch positions. [Modes for carrying out the invention]

[0020] The advantages and features of this specification, and the methods for achieving them, will become clear with reference to the embodiments described below in detail, along with the accompanying drawings. However, this specification is not limited to the embodiments disclosed below, but can be embodied in a variety of different forms. These embodiments are provided to complete the disclosure of this specification and to fully inform those ordinary skill in the art to which this specification belongs of the scope of the invention, and this specification is defined only by the scope of the claims.

[0021] The shapes, sizes, proportions, angles, and quantities disclosed in the drawings for the purpose of illustrating embodiments of this specification are illustrative, and this specification is not limited to those depicted. The same reference numerals throughout the specification refer to the same components. In addition, if a specific description of related known technology is deemed to obscure the gist of this specification, such description will be omitted. Where "includes," "has," "becomes," etc., as used in this specification, other parts may be added unless "only" is used. When a component is expressed singularly, it includes cases where it includes multiple components unless otherwise explicitly stated.

[0022] When interpreting the constituent elements, even if not explicitly stated elsewhere, they shall be interpreted as including a margin of error.

[0023] When describing temporal relationships, for example, when describing the sequence of events using phrases such as "after," "following," "next," or "before," it is acceptable to include cases that are not consecutive, unless "immediately" or "directly" is used.

[0024] In descriptions of signal flow relationships, for example, if it is stated that "a signal is transmitted from node A to node B," as long as the words "immediately" or "directly" are not used, it may include cases where the signal is transmitted from node A to node B via another node.

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

[0026] The features of the various embodiments described herein can be combined or linked together, either partially or entirely, and are technically capable of various interlocking and driving mechanisms. Each embodiment can be implemented independently of the others or in conjunction with them.

[0027] The following describes the provision of an in-cell touch display device that can improve touch sensitivity and touch recognition accuracy according to several embodiments.

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

[0029] Referring to Figures 1 and 2, the in-cell touch display device may include a display panel 100, a power supply circuit 200, a power 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 multiple subpixels (SP) and multiple touch electrodes (TE), and can be time-division driven for a display period (Td) and a touch period (Tt). The multiple touch electrodes (TE) can be embedded in the pixel array to sense touch input.

[0031] During the display period (Td), the data voltage corresponding to the 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 is driven so that touch input can be detected.

[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 the input power supply (VIN) and the 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 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 the high potential power supply voltage (Vdd) and the low potential power supply voltage (Vss) based on the input power supply (VIN) and the ground power supply (GND), and supply them to one end of the first capacitor (Cmod1) of the first RLC circuit and the second capacitor (Cmod2) of the second RLC circuit, respectively.

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

[0036] Furthermore, the second power supply circuit 220 can supply a first modulation control voltage (Vmod1) to a level having a constant period and amplitude with respect to the level of the high potential power supply voltage (Vdd) during the touch period, and can supply a second modulation control voltage (Vmod2) to a level having a constant period and amplitude with respect to the level of the low potential power supply voltage (Vss).

[0037] Furthermore, the second power supply circuit 220 can generate a high-potential gate drive voltage (Vgh) and a low-potential gate drive voltage (Vgl) based on the input power supply (VIN) and ground power supply (GND) during the indicated 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 indicated period.

[0039] Furthermore, the second power supply circuit 220 can, during the touch period, convert the high-potential gate drive voltage (Vgh) to a level having a constant period and amplitude with respect to the high-potential gate drive voltage (Vgh), and convert the low-potential gate drive voltage (Vgl) to a level having a constant period and amplitude with respect to the low-potential gate drive voltage (Vgl), and supply these to the gate driver (GDIC).

[0040] Furthermore, the second power supply circuit 220 can supply a touch drive voltage (Vtouch) having a constant period and amplitude to the touch drive circuit (ROIC) which senses changes in the capacitance of the touch electrode (TE) during the touch period.

[0041] Furthermore, 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 modulation circuit 400 may include a first RLC circuit (Rmod1, Lmod1, Cmod1) in which a resistor, inductor, and capacitor are connected in parallel to a high-potential power line (PL1) that supplies a high-potential power supply voltage (Vdd) to the display panel 100, and a second RLC circuit (Rmod2, Lmod2, Cmod2) in which a resistor, inductor, and capacitor are connected in parallel to a low-potential power line (PL2) that supplies a low-potential power supply voltage (Vss) to the display panel 100.

[0043] The power supply modulation circuit 400 can, during the touch period, modulate the high potential power supply voltage (Vdd) and low potential power supply voltage (Vss) into a high potential modulated voltage (Vdd_mod) and a low potential modulated voltage (Vss_mod) having resonant frequencies of resistors, inductors, and capacitors, and supply them to multiple subpixels (SP) of the display panel 100.

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

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

[0046] Furthermore, the first modulation control voltage (Vmod1) can be applied to a level having a constant period and amplitude with respect to the level of the high potential power supply voltage (Vdd) during the touch period, and the second modulation control voltage (Vmod2) can be applied to a level having a constant period and amplitude with respect to the level of the low potential power supply voltage (Vss).

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

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

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

[0050] The node between the first distribution resistor (R1) and the second distribution resistor (R2) is the output terminal of the reference voltage (Vref), and the output terminal of the reference voltage (Vref) may be connected to the input terminal of the reference voltage (Vref) of a touch drive circuit (ROIC) that senses changes in the 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 modulated voltage (Vdd_mod) and low-potential modulated 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 video data input using a gamma voltage (Vgamma) into a corresponding data voltage, and can supply the data voltage to the source electrode of the subpixel (SP) scan transistor (T1) 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 drive voltage (Vgh) and a low-potential gate drive 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 generate a touch drive signal having the same period and amplitude as the high-potential modulated voltage (Vdd_mod) and the low-potential modulated voltage (Vss_mod) using the touch drive voltage (Vtouch), and can supply the touch drive signal to multiple touch electrodes (TE) of the display panel 100.

[0055] Furthermore, the touch drive circuit (ROIC) can sense changes in the capacitance of the touch electrode (TE), convert the sensed voltage into a digital signal called sensed data (DA_sen), and provide the sensed data (DA_sen) to the controller 300.

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

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

[0058] In the case of in-cell touch technology, where touch electrodes (TEs) are directly designed on the backplane of the thin-film transistors in an organic light-emitting display panel, the distance between the touch electrodes (TEs) and the display electrodes (DEs) is relatively close, resulting in a very large parasitic capacitance between the two electrodes.

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

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

[0061] As shown in Figures 3a and 3b, when the charge of the touch electrode (TE) is sensed by modulating the reference voltage (Vref), the amount of charge stored in the feedback capacitor (Cfb) can be (Cp + Cf) * Vref.

[0062] In this case, the amount of charge that can be stored in the feedback capacitor (Cfb) is limited, so as the parasitic capacitance of the parasitic capacitor (Cp) increases, the amount of charge that can be stored in the feedback capacitor (Cfb) relatively decreases, and the touch performance deteriorates.

[0063] Thus, when designing in-cell touch in organic light-emitting display panels, the parasitic capacitance of the touch electrode (TE) can become very large, reducing touch performance, and the need to satisfy this large parasitic capacitance can increase power consumption. Furthermore, the touch electrode driving voltage can distort the display signal through coupling capacitors with adjacent display electrodes, potentially degrading image quality. Additionally, when driving the display and touch simultaneously, the parasitic capacitance can affect both the display electrode (DE) and the touch electrode (TE), potentially degrading both image quality and touch performance simultaneously.

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

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

[0066] Referring to Figures 4a and 4b, when a drive voltage with the same period and amplitude is applied to the touch electrode (TE) and the display electrode (DE), there is no voltage difference across the electrodes of the parasitic capacitor (Cp), and therefore the amount of charge charged to the parasitic capacitor (Cp) remains unchanged.

[0067] On the other hand, in the case of a 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 to it, so the amount of charge charged to the finger capacitor (Cf) becomes proportional to the drive voltage.

[0068] Figures 5a and 5b show the equivalent circuit and touch driving state 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 equivalent to the case where a pulsed drive voltage is applied only to the ground electrode of the finger (FIN) in a DC state.

[0070] In this case, the amount of charge being sensed can be expressed as the driving voltage generated by the finger (FIN) multiplied by the capacitance of the finger capacitor (Cf).

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

[0072] Furthermore, returning to the description of Figures 1 and 2, an in-cell touch display device according to one embodiment of the present disclosure can generate a modulated voltage having the same period and amplitude for the display electrode and the touch electrode.

[0073] In the case of organic light-emitting display panels, the power supply voltage can be divided into the high potential power supply voltage (Vdd) and low potential power supply voltage (Vss) that supply current, as well as the gate voltage (or scan pulse) and 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 the input power supply (VIN) and the 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 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 the high potential power supply voltage (Vdd) and the low potential power supply voltage (Vss) based on the input power supply (VIN) and the ground power supply (GND), and provide these to one end of the first capacitor (Cmod1) of the first RLC circuit and the second capacitor (Cmod2) of the second RLC circuit.

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

[0077] Furthermore, the power supply circuit 200 can convert the high-potential gate drive voltage (Vgh) and the low-potential gate drive voltage (Vgl) to levels with a constant period and amplitude during the touch period and supply them to the gate driver (GDIC).

[0078] Furthermore, the power supply circuit 200 can provide the touch drive circuit (ROIC) with a touch drive voltage (Vtouch) having a constant period and amplitude during the touch period. The power supply circuit 200 can also convert the gamma voltage (Vgamma) to a level having a constant period and amplitude and provide it 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 modulated voltage (Vdd_mod) and a low-potential modulated 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, during the touch period, modulate the high-potential power supply voltage (Vdd) and low-potential power supply voltage (Vss) into high-potential modulated voltage (Vdd_mod) and low-potential modulated voltage (Vss_mod) having the same period and amplitude as the touch driving voltage (Vtouch), and provide them to multiple sub-pixels.

[0081] Furthermore, the power supply modulation circuit 400 can provide the gate driver (GDIC) and source driver (SDIC) with a modulated display voltage having the same period and amplitude as the touch drive voltage (Vtouch), based on a high-potential modulation voltage (Vdd_mod) and a low-potential modulation voltage (Vss_mod).

[0082] Furthermore, the power supply modulation circuit 400 can provide the touch drive circuit (ROIC) with a modulated reference voltage having the same period and amplitude as the touch drive voltage (Vtouch), based on a high-potential modulation voltage (Vdd_mod) and a low-potential modulation voltage (Vss_mod).

[0083] Figures 6a and 6b show the voltage characteristics of the RLC parallel circuit and the values ​​of τ and ωd. Figures 7a and 7b show the RLC parallel circuit with a modulated voltage applied and the voltage characteristics with the modulated voltage applied.

[0084] Referring to Figures 6a and 6b, when the switch in the RLC parallel circuit is turned on, the voltage applied to the circuit is as shown in <Equation 1> below.

[0085]

number

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

[0087] Under the conditions described above, applying five modulation control voltage pulses to the starting section, as shown in Figures 7a and 7b, yields a waveform like that shown in Figure 7b. When τ is large and ωd is small, it can be seen that the applied modulation control voltage (Vmod) is superimposed on the high-potential power supply voltage (Vdd) and output.

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

[0089] Referring to Figure 8, if the high potential power supply voltage (Vdd) and low potential power supply voltage (Vss) are designed using resistors (Rmod1, Rmod2), inductors (Lmod1, Lmod2), and capacitors (Cmod1, Cmod2) with the same values, and the same modulation control voltage (Vmod1, Vmod2) is applied, the voltage difference between nodes A and B can always be kept constant.

[0090] In other words, 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 current flowing through them can be kept constant regardless of the modulation control voltages (Vmod1, Vmod2).

[0091] Furthermore, when 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 component of the high-potential modulation voltage (Vdd_mod) and the low-potential modulation voltage (Vss_mod) can be significantly reduced.

[0092] According to embodiments of this disclosure, when applying in-cell touch sensor technology to a display panel, touch sensitivity and touch recognition accuracy can be improved by preventing the formation of parasitic capacitance between the touch electrode and the display electrode.

[0093] Furthermore, the thickness of the display panel can be reduced, improving the realization of curved surfaces and reducing image quality degradation caused by crosstalk with touch voltage.

[0094] Furthermore, improved touch sensitivity allows for easier generation of uplink signals, enabling active pen input.

[0095] Furthermore, since the frequency and attenuation constant can be adjusted by the resistance value, it is possible to construct the circuit even without a large inductor.

[0096] One aspect of this disclosure of an in-cell touch display device enables the implementation of in-cell touch sensor technology in an organic light-emitting display panel.

[0097] Figure 9 shows 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 Figure 9, the display panel 100 of an in-cell touch display device according to one aspect of the present disclosure may include a substrate (SUB), a transistor formation layer (TRL), a light-emitting element layer (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) that form a coupling capacitor (Cct). The plurality of touch electrodes (TE) may be formed of transparent electrodes and may be formed on a substrate (SUB) at regular intervals. Alternatively, the touch electrodes (TE) may be formed on the same layer as the metal of the transistor formation layer (TRL), using the same material and the same process as the metal of the transistor formation layer (TRL).

[0101] A light-emitting element layer (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 a transistor formation layer (TRL) at regular intervals. 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 layer (AE, EL, CE). When a touch object (FIN) is touched to 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 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). The formation of finger capacitors (Cf) and coupling capacitors (Cct) on the display panel 100 allows touch to be detected regardless of the position of the touch on the display panel.

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

[0105] Furthermore, when expressing high gradation, the anode electrode (AE) located between the touch electrode (TE) and the cathode electrode (CE) reduces the resistance of the driving thin-film transistor. This creates a series capacitor between the cathode electrode (CE) and the anode electrode (AE) and the driving thin-film transistor and its gate-source capacitor, thus significantly reducing its influence on the coupling capacitor (Cct).

[0106] Therefore, when an object touches the display panel 100, the change in capacitance of the finger capacitor (Cf) and coupling capacitor (Cct) formed within the display panel 100 can be sensed to detect the touch.

[0107] Figure 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 Figure 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] Multiple touch electrodes (TEs) may be arranged in a grid pattern within the display area.

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

[0112] Figure 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 Figure 11, the display panel 100 may include a substrate (SUB), a transistor formation layer (TRL) on which thin-film transistors (TFTs) and touch electrodes (TEs) are formed, light-emitting elements (AE, EL, CE), and a cover layer (CL).

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

[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] A thin-film transistor (TFT) semiconductor 112 may be formed on the buffer layer 111.

[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 on 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 can be electrically connected to the semiconductor 112 through contact holes.

[0121] Furthermore, touch wiring (TL) may be formed on the interlayer insulating layer 115. The touch wiring (TL) can be electrically connected to the touch electrode (TE) through contact holes.

[0122] In one example, the touch wiring (TL) may be formed on the same layer as the source electrode 116 and the drain electrode 117. Alternatively, the touch wiring (TL) may be formed on a different layer from the source electrode 116 and the drain electrode 117, and in a direction aligned with the data wiring (not shown in Figure 11). A data voltage may be applied to the data wiring, and it can be electrically connected to the gate electrode 114 of the drive transistor via a scan transistor (not shown in Figure 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 flattening layer 119 may be formed on the first flattening layer 118.

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

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

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

[0128] A light-emitting layer (EL) may be formed on the anode electrode (AE). The light-emitting layer (EL) may be made of an organic light-emitting 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 this disclosure, a touch drive signal having a constant period and amplitude is applied to the touch electrode (TE) during the touch period, and a low-potential modulated voltage (Vss_mod, Figure 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 a coupling capacitor (Cct) between the touch electrode (TE) and the cathode electrode (CE) enables touch detection regardless of the touch position.

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

[0134] Furthermore, when expressing high gradation, the anode electrode (AE) located between the touch electrode (TE) and the cathode electrode (CE) reduces the resistance of the driving thin-film transistor. This creates a series capacitor between the cathode electrode (CE) and the anode electrode (AE) and the driving thin-film transistor and its gate-source capacitor, thus significantly reducing the influence on the coupling capacitor (Cct). This enables touch sensing.

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

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

[0137] Furthermore, 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 modulated voltage (Vdd_mod) and the low potential modulated voltage (Vss_mod).

[0138] Furthermore, 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-voltage modulated voltage (Vdd_mod) and the low-voltage modulated voltage (Vss_mod).

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

[0140] In this case, the touch signal is differentiated twice by passing through an object capacitor (Cf) and a coupling capacitor (Cct) twice. The in-cell touch display device according to this disclosure has a sensor circuit for detecting the touch signal that 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 Figure 1).

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

[0142] Referring to Figure 12, the sensor circuit 500 senses the touch signal by first integrating the signal output from the touch electrode (TE) and then second integrating the integrated signal.

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

[0144] The first integrator 510 may include a first operational amplifier (AMP) having a first input terminal for receiving the output signal of a touch electrode (TE) and a second input terminal to which a reference voltage (Vref) is applied, and a first feedback capacitor (Cfb1) connected 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 the touch period, the touch drive signal applied to the touch electrode (TE) has a constant period and amplitude. These touch drive signals are differentiated twice through the object capacitor (Cf) and the coupling capacitor (Cct). The sensor circuit 500 can reconstruct the touch drive signal by integrating the signal output from the touch electrode (TE) twice using the first integrator 510 and the second integrator 520.

[0147] Figure 13 shows the driving state of an in-cell touch display device according to one embodiment of the present disclosure.

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

[0149] Furthermore, Figure 13 shows the voltage state of the equivalent circuit when touched, and assuming that the potential of the touching finger is modulated, the sensor method is as follows.

[0150] First, the modulated signal transmitted by the finger is converted into a first-order derivative signal via the object capacitor (Cf). That is, the modulated signal instantaneously passes through and exits via the resistor (Rs). The first-order derivative signal is transmitted to the first integrator 510 via the coupling capacitor (Cct), but at this point the signal is also second-order derivative before being input to the first integrator 510. This signal is integrated via the first integrator 510 and converted into a form similar to the signal output via the object capacitor (Cf). Furthermore, it is restored to a form similar to the original modulated signal via 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] Figure 14 shows a drive timing diagram for an in-cell touch display device according to one embodiment of the present disclosure.

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

[0153] (2) shows the signal after first differentiation through the object capacitor (Cf), and (3) shows the signal after second differentiation through the coupling capacitor (Cct). (4) shows the signal after first integration by the first integrator 510. Here, the signal after first integration is the same as the inverse signal of the signal after first differentiation. (5) shows the signal after second integration by the second integrator 520. Here, the signal after second integration is the same as the signal obtained by restoring the signal in (1).

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

[0155] To verify the operating characteristics, a simulation was performed using a display panel 100 configured as shown in Figure 15. First, the pixel unit consisted of a sheet resistor (Rs) and a parasitic capacitor (Cp), and a resistor (Rol) was placed between the sheet resistor (Rs), to which a low potential power supply voltage (Vss) was supplied, and the high potential power supply voltage (Vdd). Here, the resistor (Rol) acts as a series resistor between the driving thin-film transistor and the light-emitting element.

[0156] The touch unit 110 consisted of 5x5 pixel units, and the display panel 100 consisted of 4x5 touch units 110. The outer casing of the display panel 100 was supplied with a low-potential power supply voltage (Vss) via low-potential power supply voltage wiring. The magnitudes of the resistors (Rol) and parasitic capacitors (Cp) were set to be equivalent to the values ​​of the 20 touch units 110 in the display panel.

[0157] In one example, under the conditions of a sheet resistance of 87Ω / sh, touch wiring resistance of 500Ω, object capacitor (Cf) of 1pF, and modulation control voltage (Vmod) of 10V, the result obtained for one pulse is shown in Figure 17. The touch drive signal applied by the modulation control voltage pulse does not spread widely through the panel's sheet resistance, but is output in 3 to 4 regions of the touch electrode (TE), allowing the touch position to be determined.

[0158] Thus, according to the embodiments of this disclosure, since touch electrodes are formed during the backplane process of the thin-film transistor, a touch function can be implemented in the organic light-emitting display panel with a minimum number of steps.

[0159] Furthermore, by placing touch electrodes within the transistor deposition layer, and utilizing 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, two integrators can be integrated into the sensor circuit to address the problem of the touch signal being differentiated twice, thereby enabling accurate detection of the touch signal.

[0160] Furthermore, the thickness of the display panel can be reduced compared to add-on touch, thus reducing the bezel size.

[0161] Furthermore, because there are no touch electrodes on the organic light-emitting element, the transmittance can be improved compared to existing touch technologies.

[0162] Furthermore, by forming a touch electrode using a transparent electrode within the backplane of the thin-film transistor, it becomes possible to emit light from both the top and bottom of the organic light-emitting element.

[0163] Furthermore, because the touch electrodes are located within the backplane of the thin-film transistor, it enables double-sided touch.

[0164] Furthermore, it is possible to reduce touch costs and production energy, thereby realizing process optimization.

[0165] Furthermore, since it is not necessary to satisfy the large parasitic capacitance between the touch electrode and the display electrode, power consumption can be reduced, making it possible to achieve low power consumption.

[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 layer formed on the transistor formation layer and including an anode electrode, a light-emitting layer, and a cathode electrode, wherein a plurality of touch electrodes forming a coupling capacitor with the cathode electrode of the light-emitting layer may be formed within the transistor formation layer.

[0167] According to one aspect of this 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.

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

[0169] According to one aspect of this disclosure, the touch electrode may be formed on a substrate within a transistor deposition layer.

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

[0171] According to one aspect of this disclosure, the invention may further include touch wiring formed within the transistor deposition layer and electrically connected to the touch electrode.

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

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

[0174] According to one aspect of this disclosure, during the touch period, a touch drive signal having a constant period and amplitude may be applied to the touch electrode, and a low-potential modulated 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 this disclosure, the touch electrode may be formed of a transparent electrode.

[0176] An in-cell touch display device according to another aspect of the present disclosure includes a plurality of subpixels having light-emitting elements and thin-film transistors, and includes a plurality of touch electrodes formed in a transistor formation layer on which the thin-film transistors are formed, forming a cathode electrode of the light-emitting element and a coupling capacitor, wherein the cathode electrode may include a display panel arranged on the plurality of touch electrodes, and a sensor circuit that senses a touch signal by linearly integrating the signal output from the touch electrodes and quadratically integrating the integrated signal.

[0177] According to other aspects of this disclosure, the sensor circuit may include a first integrator that integrates the signal output from the touch electrode in the first order, and a second integrator that integrates the signal integrated by the first integrator in the second order.

[0178] In other aspects of this disclosure, the first integrator may include a first operational amplifier having a first input terminal for receiving an output signal from a touch electrode and a second input terminal to which a reference voltage is applied, and a first feedback capacitor connected between the first input terminal and the output terminal of the first operational amplifier.

[0179] In other aspects of this disclosure, the second integrator may include 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 a reference voltage is applied, and a second feedback capacitor connected between the third input terminal and the output terminal of the second operational amplifier.

[0180] According to other aspects of this disclosure, during the touch period, a touch drive signal having a constant period and amplitude may be applied to the touch electrode, a low-potential modulated 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 other aspects of this disclosure, the 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 layer formed on the transistor formation layer and including an anode electrode, a light-emitting layer, and a cathode electrode, wherein a plurality of touch electrodes may be formed within the transistor formation layer and can form a coupling capacitor with the cathode electrode of the light-emitting layer.

[0182] According to other aspects of this 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 other aspects of this disclosure, the sensor circuit can sense changes in the capacitance of the object capacitor and the coupling capacitor by at least one integrator when a touch object touches the cover layer.

[0184] As described above, the present invention has been explained with reference to the illustrative drawings, but it is obvious that the present invention is not limited by the embodiments and drawings disclosed herein, and that various modifications can be made by an ordinary person of 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 embodiments of the present invention have been described above, it is natural to acknowledge that predictable effects can be obtained from such configuration.

Claims

1. circuit board and A transistor formation layer formed on the substrate, comprising a semiconductor, a source electrode, a drain electrode, and a gate electrode, A light-emitting layer formed on the transistor formation layer, including an anode electrode, a light-emitting layer, and a cathode electrode, A sensor circuit including a first integrator that linearly integrates the signal output from one touch electrode, and a second integrator that quadraticly integrates the signal integrated by the first integrator, Includes, The cathode electrode of the light-emitting element layer and the plurality of touch electrodes forming a coupling capacitor are formed within the transistor formation layer. A cover layer is further formed on the light-emitting element layer, and when a touch object touches the cover layer, an object capacitor is formed between the touch object and the cathode electrode. The sensor circuit senses the change in capacitance of the object capacitor and the coupling capacitor from the plurality of touch electrodes via the single touch electrode when the touch object touches the cover layer. The first integrator is, A first operational amplifier having a first input terminal for receiving the output signal of the touch electrode and a second input terminal to which a reference voltage is applied, A first feedback capacitor is connected between the first input terminal and the output terminal of the first operational amplifier, Includes, The second integrator is, 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 is connected between the third input terminal and the output terminal of the second operational amplifier, Includes, During the touch period, a touch drive signal having a constant period and amplitude is applied to the touch electrode, a low-potential modulated 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. In-cell touch display device.

2. The touch electrode is formed on the substrate within the transistor formation layer, and is arranged in the same layer as the gate electrode or in 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.

3. The transistor formation layer further includes touch wiring formed within it and electrically connected to the touch electrode, The in-cell touch display device according to claim 1.

4. 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 3.

5. The touch wiring is formed in a different layer from the source electrode and drain electrode of the transistor formation layer, and in a direction parallel to the data wiring. The in-cell touch display device according to claim 3.

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

7. circuit board and A plurality of touch electrodes are formed on the upper surface of the substrate at predetermined intervals, A buffer layer formed on the substrate and the plurality of touch electrodes, A transistor formation layer formed on the buffer layer, comprising a semiconductor, a source electrode, a drain electrode, and a gate electrode, A light-emitting layer formed on the transistor formation layer, including a plurality of anode electrodes, a light-emitting layer and a cathode electrode, Includes, Each of the plurality of touch electrodes is positioned between the upper surface of the substrate and the lower surface of the buffer layer, forming a coupling capacitor with the cathode electrode of the light-emitting element layer. A cover layer is further formed on the light-emitting layer, When a touch object touches the cover layer, an object capacitor is formed between the touch object and the cathode electrode, and a coupling capacitor is formed between the cathode electrode and at least one of the plurality of touch electrodes. In-cell touch display device.

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