In-cell touch display device

Abstract

This invention provides an embedded touch display device, wherein embedded touch sensor technology can be implemented in an organic light-emitting diode (OLED) display panel. An embedded touch display device may include: a substrate; a transistor forming layer formed on the substrate and comprising a semiconductor, a source electrode, a drain electrode, and a gate electrode; and a light-emitting element layer formed on the transistor forming layer and comprising an anode electrode, a light-emitting layer, and a cathode electrode, wherein a plurality of touch electrodes may be formed in the transistor forming layer, and these touch electrodes form a coupling capacitor with the cathode electrode of the light-emitting element layer.

Description

Technical Field

[0001] The invention relates to an embedded touch display device. Prior Art

[0002] With the development of the information society, various types of display devices for displaying images are being developed. In addition, the development of touch technology that uses touch-based input methods has enabled users to easily, intuitively, and conveniently input information or commands to display devices.

[0003] As mentioned above, to apply touch-based input methods to display devices, a touch panel containing touch sensors must be separately manufactured and coupled to the display panel. This approach has the disadvantage of increasing the size and thickness of the device and complicating the manufacturing process. Therefore, embedded touch sensor technology is being developed, which embeds touch sensors into the display panel, eliminating the need for separate touch panel manufacturing. Summary of the Invention

[0004] Designing and manufacturing display panels with embedded touch sensors is a technically challenging endeavor. Furthermore, when a touch sensor containing multiple touch electrodes is embedded in a display panel, the likelihood of parasitic capacitance between the touch sensor and the display drive electrodes or display drive lines, or between the touch sensor and the display drive lines, increasing significantly due to the proximity of the touch sensor to the display drive electrodes or display drive lines within the display panel, can significantly increase. This increase in parasitic capacitance can lead to a decrease in touch sensitivity.

[0005] Specifically, when embedded touch sensor technology is applied to an organic light-emitting diode display panel that emits light itself, parasitic capacitance may be further increased due to the structural characteristics of the organic light-emitting diode display panel.

[0006] Therefore, this specification is dedicated to providing an embedded touch display device, wherein the embedded touch sensor technology can be implemented in an organic light emitting diode display panel.

[0007] The purpose of one embodiment of the present specification is not limited to the above-mentioned purpose, and a person having ordinary knowledge in the technical field can clearly understand other purposes not mentioned from the following description.

[0008] According to one aspect of the present invention, an embedded 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, a light-emitting layer, and a cathode electrode. A plurality of touch electrodes may be formed in the transistor formation layer, and these touch electrodes and the cathode electrode of the light-emitting element layer form a coupling capacitor.

[0009] According to another aspect of the present invention, an embedded touch display device may include: a display panel including a plurality of sub-pixels having light-emitting elements and thin-film transistors, and a plurality of touch electrodes formed in a transistor-forming layer including thin-film transistors and forming coupling capacitors with cathode electrodes of the light-emitting elements, the cathode electrodes being disposed above the plurality of touch electrodes; and a sensing circuit configured to sense touch signals by performing a primary integration of output signals from the touch electrodes and a secondary integration of the integrated output signals. Simple diagram description

[0010] FIG. 1 shows an embedded touch display device according to an embodiment of the present invention. FIG. 2 shows a timing diagram of an embedded touch display device according to an embodiment of the present invention. 3A and 3B show a sensing circuit and a touch driving state of a touch driving circuit according to a first embodiment of the present invention. 4A and 4B show a sensing circuit and a touch driving state of a touch driving circuit according to a second embodiment of the present invention. 5A and 5B show an equivalent circuit and a touch driving state of a touch driving circuit according to a second embodiment of the present invention. 6A and 6B show a parallel RLC circuit and voltage characteristics according to the values ​​of τ and ωd. 7A and 7B show a parallel RLC circuit to which a modulation voltage is applied and voltage characteristics according to the application of the modulation voltage. FIG. 8 shows a power modulation circuit for an embedded touch display device according to an embodiment of the present invention. FIG9 shows a cross-sectional view of a display panel in an embedded touch display device according to an embodiment of the present invention. FIG10 schematically shows a touch sensor structure in an embedded touch display device according to an embodiment of the present invention. FIG11 shows a cross-sectional view of a display panel in an embedded touch display device according to an embodiment of the present invention. FIG. 12 shows a sensing circuit in an embedded touch display device according to an embodiment of the present invention. FIG. 13 shows the driving state of an embedded touch display device according to an embodiment of the present invention. FIG. 14 shows a driving timing diagram in an embedded touch display device according to an embodiment of the present invention. FIG. 15 shows a display panel in an embedded touch display device according to an embodiment of the present invention. FIG. 16 shows an equivalent circuit diagram of the touch unit in FIG. 15 according to an embodiment of the present invention. FIG. 17 shows output values ​​of touch electrodes according to the touch positions shown in FIG. 15 according to one embodiment of the present invention. Implementation Method

[0011] The advantages and features of this specification, as well as methods for achieving these advantages and features, will become apparent with reference to the embodiments described in detail below in conjunction with the accompanying drawings. However, this specification is not limited to the embodiments disclosed below, but can be implemented in a variety of different forms. These embodiments are provided solely to provide a complete disclosure of this specification and to fully inform those skilled in the art of the present invention of the scope of this specification. This specification is limited solely by the scope of the appended claims.

[0012] Because the shapes, sizes, proportions, angles, quantities, and the like disclosed in the drawings used to describe the embodiments of this specification are exemplary, this specification is not limited to the items shown. Identical reference numerals refer to identical components throughout this specification. Furthermore, when describing the present invention, detailed descriptions of related known technologies may be omitted when it is determined that such detailed descriptions would unnecessarily obscure the main purpose of this specification. When the terms "include," "have," and "comprise" are used in this specification, additional components may be included unless "only" is used. When a component is expressed in the singular, this includes the case where the component is provided in plural, unless otherwise expressly stated.

[0013] When interpreting a component, even if there is no separate explicit description, the component should be interpreted as including the error range.

[0014] When describing a temporal relationship, for example, using the terms "after", "subsequently", "then", "before", etc., it may include non-continuous situations unless the terms "immediately" or "directly" are used.

[0015] In the description of a signal flow relationship, for example, in the case of "a signal is sent from node A to node B", unless "immediately" or "directly" is used, the case where the signal is sent from node A to node B via another node can be included.

[0016] Although terms such as "first" and "second" are used to describe various components, these components are not limited by these terms. These terms are used only to distinguish one component from another. Therefore, within the technical spirit of this specification, the first component described below may also be the second component.

[0017] The features of the various embodiments of this specification may be partially or completely coupled or combined, and the interaction and driving of various technologies are feasible. Moreover, the various embodiments may be implemented independently of each other or implemented together through an associated relationship.

[0018] Hereinafter, an embedded touch display device capable of improving touch sensitivity and touch recognition accuracy according to some embodiments will be described.

[0019] Figure 1 shows an embedded touch display device according to an embodiment of the present invention. Figure 2 shows a timing diagram of an embedded touch display device according to an embodiment of the present invention.

[0020] 1 and 2 , the embedded 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 driving circuit ROIC, a controller 300, etc.

[0021] The display panel 100 may include a plurality of sub-pixels SP and a plurality of touch electrodes TE, and may be driven in a time-division manner during a display time Td and a touch time Tt. The plurality of touch electrodes TE may be embedded in the pixel array to detect touch input.

[0022] During the display time Td, a data voltage corresponding to the image signal may be written on the pixel array of the display panel 100, and during the touch time Tt, the touch electrodes TE of the display panel 100 may be driven to detect a touch input.

[0023] The power supply circuit 200 may include: a first power supply circuit 210; and a second power supply circuit 220.

[0024] The first power supply circuit 210 can generate a high-potential power voltage V dd and a low-potential power voltage V ss based on the input power supply VIN and the ground GND, and supply the high-potential power voltage V dd and the low-potential power voltage V ss to the first RLC circuit (including a first resistor R mod1, a first inductor L mod1 and a first capacitor C mod1) and the second RLC circuit (including a second resistor R mod2, a second inductor L mod2 and a second capacitor C mod2) of the power modulation circuit 400, respectively.

[0025] The second power supply circuit 220 can generate a first modulation control voltage V mod1 and a second modulation control voltage V mod2 for modulating the high potential power voltage V dd and the low potential power voltage V ss based on the input power source VIN and the ground GND, and supply the first modulation control voltage V mod1 and the second modulation control voltage V mod2 to one end of the first capacitor C mod1 of the first RLC circuit and one end of the second capacitor C mod2 of the second RLC circuit, respectively.

[0026] During the display time Td, the second power supply circuit 220 can supply the first modulation control voltage V mod1 at the level of the high potential power voltage V dd, and supply the second modulation control voltage V mod2 at the level of the low potential power voltage V ss.

[0027] In addition, during the touch time Tt, the second power supply circuit 220 can supply the first modulation control voltage V mod1 at a level with a predetermined period and amplitude relative to the level of the high potential power voltage V dd, and supply the second modulation control voltage V mod2 at a level with a predetermined period and amplitude relative to the level of the low potential power voltage V ss.

[0028] In addition, during the display time Td, 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 source VIN and the ground GND, and supply the high potential gate driving voltage Vgh and the low potential gate driving voltage Vgl to the gate driver GDIC.

[0029] In addition, during the display time Td, the second power supply circuit 220 may supply the gamma voltage Vgamma to the source driver SDIC based on the input power VIN and the ground GND.

[0030] Furthermore, during the touch time Tt, the second power supply circuit 220 can modulate the high-potential gate driving voltage Vgh to a level having a predetermined period and amplitude relative to the high-potential gate driving voltage Vgh, and modulate the low-potential gate driving voltage Vgl to a level having a predetermined period and amplitude relative to the low-potential gate driving voltage Vgl, and supply the modulated high-potential and low-potential gate driving voltages to the gate driver GDIC.

[0031] In addition, during the touch time Tt, the second power supply circuit 220 can supply a touch driving voltage Vtouch with a predetermined period and amplitude to the touch driving circuit ROIC for sensing the capacitance change of the touch electrode TE.

[0032] In addition, the second power supply circuit 220 can modulate the gamma voltage Vgamma to a level having a predetermined period and amplitude relative to the gamma voltage Vgamma, and supply the modulated gamma voltage to the source driver SDIC.

[0033] The power modulation circuit 400 may include: a first RLC circuit, in which a resistor, an inductor, and a capacitor are connected in parallel to a high-potential power line PL1 in the display panel 100, and a high-potential power voltage Vdd is supplied to the high-potential power line PL1; and a second RLC circuit, in which a resistor, an inductor, and a capacitor are connected in parallel to a low-potential power line PL2 in the display panel 100, and a low-potential power voltage Vss is supplied to the low-potential power line PL2.

[0034] During the touch time Tt, the power modulation circuit 400 can modulate the high-potential power voltage Vdd and the low-potential power voltage Vss into a high-potential modulation voltage Vdd_mod and a low-potential modulation voltage Vss_mod having a resonant frequency of a resistor, an inductor, and a capacitor, and supply the high-potential modulation voltage Vdd_mod and the low-potential modulation voltage Vss_mod to a plurality of sub-pixels SP of the display panel 100.

[0035] During the touch time Tt, the first RLC circuit can receive a first modulated control voltage V mod1 having a predetermined period and amplitude through one end of the first capacitor C mod1. During the touch time Tt, the second RLC circuit can receive a second modulated control voltage V mod2 having a predetermined period and amplitude through one end of the second capacitor C mod2.

[0036] Herein, during the display time Td, the first modulation control voltage V mod1 may be applied at a level of the high potential power voltage V dd, and the second modulation control voltage V mod2 may be applied at a level of the low potential power voltage V ss.

[0037] In addition, during the touch time Tt, the first modulation control voltage V mod1 can be applied at a level with a predetermined period and amplitude relative to the level of the high-potential power supply voltage V dd, and the second modulation control voltage V mod2 can be applied at a level with a predetermined period and amplitude relative to the level of the low-potential power supply voltage V ss.

[0038] The first RLC circuit may include: a first resistor R mod1 having one end connected to the output end of the high-potential power supply voltage V dd and the other end connected to the driving transistor DT of the sub-pixel SP; a first inductor L mod1 having one end connected to the output end of the high-potential power supply voltage V dd and the other end connected to the driving transistor DT of the sub-pixel SP; and a first capacitor C mod1 having one end connected to the output end of the first modulation control voltage V mod1 and the other end connected to the driving transistor DT of the sub-pixel SP.

[0039] The second RLC circuit may include: a second resistor R mod2 having one end connected to the output terminal of the low-potential power supply voltage V ss and the other end connected to the light-emitting element OLED of the sub-pixel SP; a second inductor L mod2 having one end connected to the output terminal of the low-potential power supply voltage V ss and the other end connected to the light-emitting element OLED of the sub-pixel SP; and a second capacitor C mod2 having one end connected to the output terminal of the second modulation control voltage V mod2 and the other end connected to the light-emitting element OLED of the sub-pixel SP.

[0040] The power modulation circuit 400 may further include: a first distribution resistor R1 having one end connected to the first power line PL1 and the other end connected to the output end of the reference voltage Vref; and a second distribution resistor R2 having one end connected to the second power line PL2 and the other end connected to the output end of the reference voltage Vref.

[0041] The node between the first distribution resistor R1 and the second distribution resistor R2 is the output end of the reference voltage Vref, and the output end of the reference voltage Vref can be connected to the input end of the touch driving circuit ROIC for sensing the capacitance change of the touch electrode TE.

[0042] Herein, during the touch time Tt, the reference voltage V ref may be modulated to a level having the same period and amplitude as the high-level modulation voltage V dd_mod and the low-level modulation voltage V ss_mod modulated by the first RLC circuit and the second RLC circuit.

[0043] The source driver SDIC may use the gamma voltage Vgamma to modulate the input image data into a corresponding data voltage, and supply the data voltage to the source electrode of the scan transistor T1 of the sub-pixel SP through the data line (or data conductor) of the display panel 100 .

[0044] The gate driver GDIC may generate a scan signal using a high potential gate driving voltage Vgh and a low potential gate driving voltage Vgl, and supply the scan signal to the gate electrode of the scan transistor T1 of the sub-pixel SP through the gate line of the display panel 100.

[0045] The touch driving circuit ROIC may use the touch driving voltage V touch to generate a touch driving signal having the same period and amplitude as the high-potential modulation voltage V dd_mod and the low-potential modulation voltage V ss_mod, and supply the touch driving signal to the plurality of touch electrodes TE of the display panel 100 .

[0046] In addition, the touch driving circuit ROIC can detect the capacitance change of the touch electrode TE, modulate the detection voltage into detection data DA_sen (which is a digital signal), and provide the detection data DA_sen to the controller 300.

[0047] The controller 300 may use the touch signal TCS to control the operation timings of the second power supply circuit 220 , the gate driver GDIC, the source driver SDIC, and the touch driving circuit ROIC.

[0048] 3A and 3B show a sensing circuit and a touch driving state of a touch driving circuit according to a first embodiment of the present invention.

[0049] In the embedded touch technology in which the touch electrode TE is directly designed on the thin film transistor backplane of the organic light emitting diode display panel, the distance between the touch electrode TE and the display electrode DE is relatively reduced, thereby significantly increasing the parasitic capacitance between the two electrodes.

[0050] In the case of an add-on touch system, 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 an embedded touch system, the distance between the touch electrode and the display electrode is very small, on the order of μm, which increases the parasitic capacitance of the parasitic capacitor Cp between the touch electrode TE and the display electrode DE and leads to a decrease in touch performance.

[0051] In the present invention, the display electrode DE can be defined as an electrode or a wire used for display driving in the display panel 100.

[0052] 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 accumulated in the feedback capacitor Cfb may become (Cp+Cf)*Vref. Here, an operational amplifier AMP is connected to the touch electrode TE and outputs the sense voltage Vsen. The feedback capacitor Cfb is connected between the input and output terminals of the operational amplifier AMP. The reference voltage Vref is applied to the other input terminal of the operational amplifier AMP. A finger capacitor Cf is formed between the finger FIN and the touch electrode TE.

[0053] In this case, since the amount of charge that can be accumulated in the feedback capacitor Cfb is limited, as the parasitic capacitance of the parasitic capacitor Cp increases, the amount of charge that can be accumulated in the feedback capacitor Cfb becomes relatively smaller, thereby reducing touch performance.

[0054] As mentioned above, when designing embedded touch in an OLED display panel, the parasitic capacitance of the touch electrode TE can become very large, thereby reducing touch performance. The need to fill this large parasitic capacitance can also increase power consumption. Furthermore, the driving voltage of the touch electrode can be coupled with the adjacent display electrode through a coupling capacitor, distorting the display signal and reducing image quality. Furthermore, when driving both the display and touch functions simultaneously, the display electrode DE and the touch electrode TE are affected by parasitic capacitance, thereby degrading both image quality and touch performance.

[0055] The present invention provides an embedded touch display device capable of improving touch sensitivity and touch recognition accuracy even when the embedded touch sensor technology is applied to an organic light emitting diode display panel.

[0056] 4A and 4B show a sensing circuit and a touch driving state of a touch driving circuit according to a second embodiment of the present invention.

[0057] 4A and 4B , when a driving voltage having the same period and amplitude is applied to the touch electrode TE and the display electrode DE, there is no voltage difference between the electrodes of the parasitic capacitor Cp, and thus the amount of charge charged in the parasitic capacitor Cp does not change.

[0058] On the other hand, when the finger capacitor Cf is located between the finger FIN and the touch electrode TE, since one side is in the ground GND state and the other side is applied with a driving voltage, the amount of charge charged in the finger capacitor Cf is proportional to the driving voltage.

[0059] 5A and 5B show an equivalent circuit and a touch driving state of a touch driving circuit according to a second embodiment of the present invention.

[0060] 5A and 5B , since the voltages are relative, it can be considered that the situation is equivalent to the case where the pulsed driving voltage is applied only to the ground electrode of the finger FIN when the input terminals of the touch electrode TE, the display electrode DE, and the reference voltage V ref are DC.

[0061] The amount of charge sensed at this time can be represented by the product of the driving voltage generated from the finger FIN and the capacitance of the finger capacitor Cf.

[0062] Therefore, when the touch electrode TE, the display electrode DE, and the input terminal of the reference voltage V ref are driven by driving signals having the same period and amplitude as described above, regardless of the parasitic capacitance of the parasitic capacitor C p, only the charge stored in the finger capacitor C f can be read, thereby improving touch performance.

[0063] Referring back to FIG. 1 and FIG. 2 , the embedded touch display device according to one embodiment of the present invention can generate a modulation voltage having the same period and amplitude in the display electrodes and the touch electrodes.

[0064] The OLED display panel may have a high potential power supply voltage V dd and a low potential power supply voltage V ss for supplying current, gate voltage (or scan pulse), data voltage, etc.

[0065] The power supply circuit 200 can generate a high potential power voltage Vdd and a low potential power voltage Vss based on an input power source VIN and a ground GND, and provide the high potential power voltage Vdd and the low potential power voltage Vss to the first RLC circuit and the second RLC circuit, respectively.

[0066] In addition, the power supply circuit 200 can generate a first modulation control voltage V mod1 and a second modulation control voltage V mod2 for modulating the high-potential power voltage V dd and the low-potential power voltage V ss based on the input power source V IN and the ground GND, and provide the first modulation control voltage V mod1 and the second modulation control voltage V mod2 to one end of the first capacitor C mod1 of the first RLC circuit and one end of the second capacitor C mod2 of the second RLC circuit, respectively.

[0067] In addition, during the display time Td, the power supply circuit 200 can provide the high potential gate driving voltage Vgh and the low potential gate driving voltage Vgl to the gate driver GDIC, and provide the gamma voltage Vgamma to the source driver SDIC.

[0068] In addition, during the touch time Tt, the power supply circuit 200 can modulate the high-potential gate driving voltage Vgh and the low-potential gate driving voltage Vgl to levels with a predetermined period and amplitude, and provide the modulated high-potential gate driving voltage Vgh and the low-potential gate driving voltage Vgl to the gate driver GDIC.

[0069] Furthermore, during the touch time Tt, the power supply circuit 200 can provide a touch driving voltage Vtouch having a predetermined period and amplitude to the touch driving circuit ROIC. Furthermore, the power supply circuit 200 can modulate the gamma voltage Vgamma to a level having a predetermined period and amplitude, and provide the modulated gamma voltage to the source driver SDIC.

[0070] The power modulation circuit 400 can use the first RLC circuit and the second RLC circuit to modulate the high-potential power voltage V dd and the low-potential power voltage V ss output from the power supply circuit 200 into the high-potential modulation voltage V dd — mod and the low-potential power voltage V ss — mod.

[0071] During the touch time Tt, the power modulation circuit 400 can modulate the high-potential power voltage Vdd and the low-potential power voltage Vss 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 driving voltage Vtouch, and provide the modulated high-potential modulation voltage Vdd_mod and the low-potential modulation voltage Vss_mod to a plurality of sub-pixels.

[0072] In addition, the power modulation circuit 400 can provide a modulated display voltage having the same period and amplitude as the touch driving voltage Vtouch to the gate driver GDIC and the source driver SDIC based on the high-voltage modulation voltage Vdd_mod and the low-voltage modulation voltage Vss_mod.

[0073] In addition, the power modulation circuit 400 can provide a modulation reference voltage having the same period and amplitude as the touch driving voltage V touch to the touch driving circuit ROIC based on the high-voltage modulation voltage V dd_mod and the low-voltage modulation voltage V ss_mod.

[0074] Figures 6A and 6B show a parallel RLC circuit and voltage characteristics according to the values ​​of τ and ωd. Figures 7A and 7B show a parallel RLC circuit to which a modulation control voltage is applied and voltage characteristics according to the application of the modulation control voltage.

[0075] 6A and 6B , when a switch of a parallel RLC circuit including a power supply voltage V, a resistor R mod, an inductor L mod, and a capacitor C mod connected in parallel is turned on, a voltage applied to the circuit is as shown in Equation 1.

[0076] [Equation 1]

[0077] In this case, the voltage characteristics according to the values ​​of τ = 1 and ωd = 50 kHz are shown in Figure 6B.

[0078] Under the above conditions, as shown in Figures 7A and 7B , applying five modulation control voltage pulses during the initial phase produces the waveform shown in Figure 7B . When τ is large and ωd is small, it can be seen that the applied modulation control voltage V mod is output by loading it onto the high-potential power supply voltage V dd .

[0079] FIG. 8 shows a power modulation circuit for an embedded touch display device according to an embodiment of the present invention.

[0080] Referring to FIG. 8 , the high-potential power supply voltage V dd and the low-potential power supply voltage V ss are designed to have first and second resistors R mod1 and R mod2, first and second inductors L mod1 and L mod2, and first and second capacitors C mod1 and C mod2 of identical values. Furthermore, when first and second modulation control voltages V mod1 and V mod2 of identical values ​​are applied, the voltage difference between node A and node B can always remain constant.

[0081] That is, the high potential power voltage Vdd and the low potential power voltage Vss are applied to the load terminal of the display panel 100, and the flowing current can be kept constant regardless of the first modulation control voltage Vmod1 and the second modulation control voltage Vmod2.

[0082] In addition, when the first modulation control voltage V mod1 and the second modulation control voltage V mod2 are generated and applied based on the high potential power voltage V dd and the low potential power voltage V ss respectively, the harmonic components of the high potential modulation voltage V dd_mod and the low potential modulation voltage V ss_mod can be significantly reduced.

[0083] According to an embodiment of the present invention, when the embedded touch sensor technology is applied to a display panel, parasitic capacitance can be prevented from being generated between the touch electrodes and the display electrodes, thereby improving touch sensitivity and touch recognition accuracy.

[0084] In addition, the thickness of the display panel can be reduced, a curved surface can be realized, and degradation of image quality caused by crosstalk with the touch voltage can be improved.

[0085] In addition, by improving touch sensitivity, an uplink signal can be easily generated, thereby realizing active pen touch.

[0086] In addition, since the frequency and damping constant can be adjusted by the resistance value, this inductor can be realized even when the inductor is not large.

[0087] An embedded touch display device according to one aspect of the present invention allows for implementation of embedded touch sensor technology in an organic light emitting diode display panel.

[0088] FIG9 shows a cross-sectional view of a display panel in an embedded touch display device according to an embodiment of the present invention.

[0089] 9 , a display panel 100 of an embedded touch display device according to one aspect of the present invention may include: a substrate SUB; a transistor formation layer TRL; a light emitting element layer (including an anode electrode AE, a light emitting layer EL, and a cathode electrode CE); and a cover layer CL.

[0090] The transistor formation layer TRL may be formed on the substrate SUB.

[0091] The transistor formation layer TRL may include a plurality of touch electrodes TE, which form a coupling capacitor Cct with the cathode electrode CE of the light-emitting element layer. The plurality of touch electrodes TE may be formed as transparent electrodes and formed on the substrate SUB at predetermined intervals. Alternatively, the touch electrodes TE may be formed using the same material and through the same process on the same layer as the metal of the transistor formation layer TRL.

[0092] A light emitting element layer (including an anode electrode AE, a light emitting layer EL, and a cathode electrode CE) may be formed on the transistor formation layer TRL.

[0093] The light-emitting element layer 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 predetermined 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.

[0094] The cover layer CL can be formed on the light-emitting element layer (including the anode electrode AE, the light-emitting layer EL, and the cathode electrode CE). When a touch object FIN (or a finger FIN) touches the cover layer CL, a capacitor can be formed between the touch object FIN and the cathode electrode. In this specification, the capacitor between the touch object FIN and the cathode electrode is referred to as the object capacitor Cf or the finger capacitor Cf. This capacitor can also be formed between the cathode electrode CE and the touch electrode TE. In this specification, the capacitor formed between the cathode electrode CE and the touch electrode TE is referred to as a coupling capacitor. When the finger capacitor Cf and the coupling capacitor Cct are formed in the display panel 100, touch detection can be performed even when the touch location is anywhere on the display panel.

[0095] The anode electrode AE ​​between the touch electrode TE and the cathode electrode CE can be considered as a floating electrode because the resistance of the driving thin film transistor becomes very large when representing a low gray scale, and thus the capacitance value of the coupling capacitor C ct can be maintained.

[0096] In addition, the influence of the anode electrode AE ​​between the touch electrode TE and the cathode electrode CE on the coupling capacitor C ct may be very small. This is because when displaying high grayscale, due to the small resistance of the driving thin film transistor, the capacitor between the cathode electrode CE and the anode electrode AE ​​will form a series capacitor with the gate-source capacitor of the driving thin film transistor.

[0097] Therefore, when an object touches the display panel 100, the touch can be detected by sensing the capacitance changes of the finger capacitor Cf and the coupling capacitor Cct formed in the display panel 100.

[0098] FIG10 schematically shows a touch sensor structure of an embedded touch display device according to an embodiment of the present invention.

[0099] 10 , the touch sensor of the display panel 100 may include: touch electrodes TE; and touch lines TL.

[0100] The cathode electrode CE may be formed on the entire surface of the display area of ​​the display panel 100 .

[0101] A plurality of touch electrodes TE may be arranged in the display area in a grid format.

[0102] The touch line TL may be electrically connected to each touch electrode TE, and the signal of each touch electrode TE may be transmitted to an external sensing circuit through the touch line TL.

[0103] FIG11 shows a cross-sectional view of a display panel in an embedded touch display device according to an embodiment of the present invention.

[0104] 11 , the display panel 100 may include: a substrate SUB; a transistor formation layer TRL in which thin film transistors TFT and touch electrodes TE are formed; a light emitting element layer (including an anode electrode AE, a light emitting layer EL, and a cathode electrode CE); and a cover layer CL.

[0105] The touch electrodes TE may be formed on the substrate SUB at predetermined intervals.

[0106] A buffer layer 111 may be formed on the substrate SUB and the touch electrode TE and may be made of an insulating material.

[0107] A semiconductor 112 of a thin film transistor (TFT) may be formed on the buffer layer 111 .

[0108] A gate insulating layer 113 may be formed on the semiconductor 112 and the buffer layer 111 .

[0109] The gate electrode 114 may be formed on the gate insulating layer 113 at a position overlapping the semiconductor 112 .

[0110] An interlayer insulating layer 115 may be formed on the gate electrode 114 and the gate insulating layer 113 .

[0111] 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.

[0112] In addition, a touch line TL may be formed on the interlayer insulating layer 115. The touch line TL may be electrically connected to the touch electrode TE through a contact hole.

[0113] For example, the touch line TL can be formed on the same layer as the source electrode 116 and the drain electrode 117. Alternatively, the touch line TL can be formed on a different layer from the source electrode 116 and the drain electrode 117 and arranged parallel to the data line (not shown in FIG11 ). A data voltage can be applied to the data line, and the gate line can be electrically connected to the gate electrode 114 of the drive transistor via a scan transistor (not shown in FIG11 ).

[0114] A first planarization layer 118 may be formed on the source electrode 116 , the drain electrode 117 , the touch line TL, and the interlayer insulating layer 115 .

[0115] The second planarization layer 119 may be formed on the first planarization layer 118 .

[0116] Meanwhile, the stacking position of the touch electrode TE is exemplary, 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 on the same layer as the gate electrode 114, or on 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.

[0117] The anode electrode AE ​​of the organic light emitting diode 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.

[0118] In addition, the bank layer 120 may be formed on a portion of the second planarization layer 119 and a portion of the anode electrode AE. The bank layer 120 may be made of an opaque material to prevent light interference between adjacent pixels.

[0119] The light emitting layer EL may be formed on the anode electrode AE ​​and may be made of an organic light emitting material.

[0120] A cathode electrode CE may be formed on the light emitting layer EL.

[0121] A cover layer CL may be formed on the cathode electrode CE. The cover layer CL may be made of a transparent material.

[0122] In the embedded touch display device according to the present invention, during the touch time Tt, a touch driving signal having a predetermined period and amplitude can be applied to the touch electrode TE, and a low-level modulation voltage Vss_mod (see FIG. 1 ) having the same period and amplitude as the touch driving signal can be applied to the cathode electrode CE.

[0123] The touch electrode TE and the cathode electrode CE may form a coupling capacitor C ct. The coupling capacitor C ct may be formed between the touch electrode TE and the cathode electrode CE, so that touch detection can be performed regardless of the touch position.

[0124] The anode electrode AE ​​between the touch electrode TE and the cathode electrode CE can be considered as a floating electrode because the resistance of the driving thin film transistor becomes very large when representing a low gray scale, and thus the capacitance value of the coupling capacitor C ct can be maintained.

[0125] Furthermore, the anode electrode AE ​​between the touch electrode TE and the cathode electrode CE may have very little effect on the coupling capacitor Cct. This is because, when displaying high grayscale, the resistance of the driving thin film transistor is low, so the capacitor between the cathode electrode CE and the anode electrode AE ​​forms a series capacitor with the gate-source capacitor of the driving thin film transistor. Therefore, touch detection can be performed.

[0126] The embedded touch display device can be driven in a time-division manner during the display time Td and the touch time Tt, and the touch driving signal during the touch time Tt can have a predetermined period and amplitude.

[0127] For example, during the touch time Tt, the high power voltage Vdd and the low power voltage Vss can be modulated into a high modulation voltage Vdd_mod and a low modulation voltage Vss_mod having the same period and amplitude as the touch driving voltage, and supplied to a plurality of sub-pixels.

[0128] In addition, the display voltages (eg, the gamma voltage Vgamma, the high gate driving voltage Vgh, and the low gate driving voltage Vgl) can be modulated to have the same period and amplitude as the touch driving voltage based on the high modulation voltage Vdd_mod and the low modulation voltage Vss_mod.

[0129] In addition, the reference voltage V ref can be modulated into a voltage having the same period and amplitude as the touch driving voltage based on the high-level modulation voltage V dd_mod and the low-level modulation voltage V ss_mod.

[0130] As described above, referring to Figures 9 to 11 , the touch electrode TE and the thin-film transistor TFT can be formed on the substrate SUB, and the light-emitting element layer (including the anode electrode AE, the light-emitting layer EL, and the cathode electrode CE) can be deposited on the touch electrode TE and the thin-film transistor TFT. When the touch object FIN touches the touch line TL, the touch signal can be transmitted to the touch line TL through the object capacitor Cf and the coupling capacitor Cct.

[0131] In this case, when the touch signal passes through the object capacitor Cf and the coupling capacitor Cct, the original signal is differentiated twice. In the embedded touch display device of the present invention, the sensing circuit for detecting touch signals has two embedded integrators and detects the touch signal by integrating it twice. In the present invention, the sensing circuit is a readout circuit and can be embedded in the touch driver circuit (ROIC) (see Figure 1).

[0132] FIG. 12 shows a sensing circuit in an embedded touch display device according to an embodiment of the present invention.

[0133] 12 , the sensing circuit 500 senses the touch signal by performing a primary integration on the signal output from the touch electrode TE and a secondary integration on the integrated signal.

[0134] The sensing circuit 500 may include: a first integrator 510 for performing a first integration on a signal output from the touch electrode TE; and a second integrator 520 for performing a second integration on the signal integrated by the first integrator 510.

[0135] The first integrator 510 may include: a first operational amplifier AMP1 having a first input terminal for receiving the output signal of the touch electrode TE and a second input terminal to which a reference voltage V ref is applied; and a first feedback capacitor C fb1 connected between the first input terminal and the output terminal of the first operational amplifier AMP1.

[0136] The second integrator 520 may include: a second operational amplifier AMP2 having a third input terminal electrically connected to the output terminal of the first operational amplifier AMP1 and a fourth input terminal to which a reference voltage V ref is applied; and a second feedback capacitor C fb2 connected between the third input terminal and the output terminal of the second operational amplifier AMP2.

[0137] During the touch time Tt, the touch drive signal applied to the touch electrode TE has a predetermined period and amplitude. The touch drive signal is differentiated twice through the object capacitor Cf and the coupling capacitor Cct. The sensing circuit 500 can restore 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 to recover the touch drive signal.

[0138] FIG. 13 shows the driving state of an embedded touch display device according to an embodiment of the present invention.

[0139] Referring to FIG. 13 , during the touch time Tt, a touch driving signal having a predetermined period and amplitude can be applied to the touch electrode TE. Furthermore, a low-level modulation voltage Vss_mod having the same period and amplitude as the touch driving signal can be applied to the cathode electrode CE. Furthermore, a reference voltage Vref having the same period and amplitude as the touch driving signal can be applied to the reference voltage input terminals of the first integrator 510 and the second integrator 520.

[0140] 13 shows the voltage state of the equivalent circuit during touch, and the sensing method assuming that the signal is modulated by the potential of the touching finger during touch is as follows.

[0141] First, the modulated signal transmitted by the finger is converted into a first differential signal through the object capacitor Cf. This means that the modulated signal is input instantaneously and then output through the sheet resistor Rs. The first differential signal is transmitted to the first integrator 510 through the coupling capacitor Cct. At this point, the signal undergoes second differentiation and is input to the first integrator 510. This signal is integrated by the first integrator 510 and converted into a form similar to the signal output through the object capacitor Cf. This signal is restored to the same form as the original modulated signal through the second integrator 520. Therefore, the final output value of the sensing circuit 500 is proportional to the magnitude of the touch input signal.

[0142] FIG. 14 shows a driving timing diagram in an embedded touch display device according to an embodiment of the present invention.

[0143] Referring to FIG. 14 , waveform ① illustrates the following situation: assuming that when a touch drive signal having a predetermined period and amplitude is applied to the touch electrode TE, the potential of the finger applied to the object capacitor Cf is modulated, and during the touch time Tt, 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.

[0144] Waveform ② shows the signal first differentiated through object capacitor Cf, and waveform ③ shows the signal second differentiated through coupling capacitor Cct. Waveform ④ shows the signal first integrated through first integrator 510. Here, the first integrated signal is the same as the inverse of the first differentiated signal. Waveform ⑤ shows the signal second integrated through second integrator 520. Here, the second integrated signal is the same as the signal restored from waveform ①.

[0145] Figure 15 shows a display panel in an embedded touch display device according to one embodiment of the present invention. Figure 16 shows an equivalent circuit diagram of the touch unit of Figure 15 according to one embodiment of the present invention. Figure 17 shows the output values ​​of the touch electrodes according to the touch positions of Figure 15 according to one embodiment of the present invention.

[0146] A simulation was performed using the display panel 100 configured as shown in FIG15 to examine operational characteristics. First, a pixel cell includes a pixel resistor R ol, which is provided between the sheet resistor R s and the parasitic capacitor C p, and between the sheet resistor R s, which is supplied with a low-potential power supply voltage V ss, and a high-potential power supply voltage V dd. Here, the pixel resistor R ol serves as a series resistor that drives the thin-film transistor and the light-emitting element.

[0147] The touch cells 110 are composed of 5×5 pixel units, and the touch panel 100 is composed of 4×5 touch cells 110. The low-potential power supply voltage Vss is supplied via a low-potential power supply voltage line external to the touch panel 100. The pixel resistors R ol and parasitic capacitors C p are sized to correspond to the values ​​of the 20 touch cells 110 in the display panel.

[0148] For example, Figure 17 shows the results of obtaining a pulse under the conditions of a sheet resistance of 87 Ω / sh, a touch line resistance of 500 Ω, an object capacitor Cf of 1 pf, and a modulation control voltage Vmod of 10 V. The touch position can be obtained by outputting touch drive signals applied by a pulse of the modulation control voltage from three and four regions of the touch electrode TE without propagating to the panel's sheet resistor.

[0149] As described above, an embedded touch display device according to one aspect of the present invention 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, wherein a plurality of touch electrodes may be formed in the transistor formation layer, and these touch electrodes and the cathode electrode of the light-emitting element layer form a coupling capacitor.

[0150] According to one aspect of the present invention, a cover layer may be further formed on the light emitting element layer, and when a touch object contacts the cover layer, an object capacitor may be formed between the touch object and the cathode electrode.

[0151] According to one aspect of the present invention, the embedded touch display device may further include a sensing circuit configured to sense capacitance changes of the object capacitor and the coupling capacitor through the touch electrodes when the touch object touches the cover layer.

[0152] According to one aspect of the present invention, the touch electrodes may be formed on the substrate and in the transistor formation layer.

[0153] According to one aspect of the present invention, the touch electrode can be arranged on the same layer as the gate electrode, or on the same layer as the source electrode and the drain electrode.

[0154] According to one aspect of the present invention, the embedded touch display device may further include a touch line formed in the transistor formation layer and electrically connected to the touch electrode.

[0155] According to one aspect of the present invention, the touch line can be formed on the same layer as the source electrode and the drain electrode of the transistor formation layer.

[0156] According to one aspect of the present invention, the touch line can be formed in a direction parallel to the data line by forming the source electrode and the drain electrode on a layer different from the transistor formation layer.

[0157] According to one aspect of the present invention, during the touch time, a touch driving signal having a predetermined period and amplitude can be applied to the touch electrode, and a low-voltage modulation voltage having the same period and amplitude as the touch driving signal can be applied to the cathode electrode.

[0158] According to one aspect of the present invention, the touch electrode can be formed as a transparent electrode.

[0159] According to another aspect of the present invention, an embedded touch display device may include: a display panel including a plurality of sub-pixels having light-emitting elements and thin-film transistors, and a plurality of touch electrodes formed in a transistor formation layer including thin-film transistors and forming coupling capacitors with cathode electrodes of the light-emitting elements, the cathode electrodes being disposed above the plurality of touch electrodes; and a sensing circuit configured to sense touch signals by performing a primary integration of output signals from the touch electrodes and a secondary integration of the integrated output signals.

[0160] According to another aspect of the present invention, the sensing circuit may include: a first integrator configured to perform a first integration on the output signal from the touch electrode; and a second integrator configured to perform a second integration on the integrated output signal integrated by the first integrator.

[0161] According to another aspect of the present invention, the first integrator may include: a first operational amplifier having a first input terminal configured to receive an output signal of 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 an output terminal of the first operational amplifier.

[0162] According to another aspect of the present invention, 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 first operational amplifier.

[0163] According to another aspect of the present invention, during the touch time, a touch drive signal having a predetermined period and amplitude can be applied to the touch electrode, a low-voltage modulation voltage having the same period and amplitude as the touch drive signal can be applied to the cathode electrode, and a reference voltage having the same period and amplitude as the touch drive signal can be applied to the second input terminal of the first operational amplifier and the fourth input terminal of the second operational amplifier.

[0164] According to another aspect of the present invention, 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; 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 cover layer formed on the light-emitting element layer, wherein when a touch object touches the cover layer, an object capacitor is formed between the touch object and the cathode electrode, and a plurality of touch electrodes may be formed in the transistor formation layer and may form a coupling capacitor with the cathode electrode of the light-emitting element layer.

[0165] According to another aspect of the present invention, a covering layer may be further formed on the light-emitting element layer, and when a touch object contacts the covering layer, an object capacitor may be formed between the touch object and the cathode electrode.

[0166] According to another aspect of the present invention, when a touch object touches the cover layer, the sensing circuit senses the capacitance changes of the object capacitor and the coupling capacitor through two integrators.

[0167] According to the embodiment of the present invention, since the touch electrodes are formed on the back plate of the thin film transistor, the touch function can be implemented in the organic light emitting diode display panel with minimal manufacturing processes.

[0168] Furthermore, by arranging the touch electrodes in the transistor formation layer and forming a coupling capacitor between the cathode electrode and the touch electrodes, the touch signal is differentiated twice by the finger capacitor formed between the touching object and the cathode electrode. By embedding two integrators in the sensing circuit, the touch signal can be accurately detected.

[0169] In addition, compared with add-on touch, the thickness of the display panel can be reduced and the size of the frame can be reduced.

[0170] In addition, since there is no touch electrode on the organic light-emitting diode, the transmittance can be increased compared with traditional touch technology.

[0171] In addition, since the touch electrode is formed by using the transparent electrode in the thin film transistor backplane, top emission and bottom emission of the organic light emitting diode can be realized.

[0172] In addition, since the touch electrodes are located in the backplane of the thin film transistor, double-sided touch can be achieved.

[0173] Furthermore, process optimization can be achieved by reducing contact costs and production energy.

[0174] In addition, since there is no need to fill the large parasitic capacitance between the touch electrode and the display electrode, power consumption can be reduced, thereby achieving low power consumption.

[0175] Specific effects are described together with the above-mentioned effects in the following detailed description of matters for carrying out the present invention.

[0176] While the present invention has been described above with reference to exemplary drawings, the present invention is not limited to the embodiments and drawings disclosed herein, and it is apparent that a person skilled in the art could make various modifications within the scope of the technical spirit of the present invention. Furthermore, even if the operational effects of the configurations according to the present invention are not explicitly described in the description of the embodiments of the present invention, it goes without saying that the effects that can be predicted by the corresponding configurations are recognized.

[0177] 100: Display panel 110: Touch unit 111: buffer layer 112: Semiconductors 113: Gate insulation layer 114: Gate electrode 115: interlayer insulation layer 116: Source electrode 117: Drain electrode 118: first planarization layer 119: Second planarization layer 120: embankment layer 200: Power supply circuit 210: First power supply circuit 220: Second power supply circuit 300: Controller 400: Power modulation circuit 500: Sensing circuit 510: First integrator 520: Second integrator ①: Waveform ②: Waveform ③: Waveform ④: Waveform ⑤: Waveform A, B: nodes AE: Anode electrode AMP: Operational amplifier AMP1: First operational amplifier AMP2: Second operational amplifier C ct: coupling capacitor CE: cathode electrode C f: Finger capacitor, object capacitor C fb: Feedback capacitor C fb1: first feedback capacitor C fb2: Second feedback capacitor CL: Covering layer C mod: capacitor C mod1: first capacitor C mod2: second capacitor C p: parasitic capacitor DA_sen: Detection data DE: Display Electrode DT: driver transistor EL: light-emitting layer FIN: finger, touch object GDIC: Gate Driver GND: Ground L mod: inductor L mod1: first inductor L mod2: second inductor OLED: light-emitting element PL1: High potential power line, first power line PL2: low potential power line, second power line R1: First distribution resistor R 2: Second distribution resistor R mod: resistor R mod1: first resistor R mod2: second resistor ROIC: Touch drive circuit R ol: Pixel resistor Rs: Chip resistor SDIC: Source Driver SP: Sub-Pixel SUB:Substrate T1: Scanning transistor TCS: Touch Control Signal Td: Display time TE: Touch electrode TFT: Thin Film Transistor TL: Touch line TRL: Transistor Formation Layer Tt: touch time V: power supply voltage Vdd: high potential power supply voltage Vdd_mod: high voltage modulation voltage V gamma: Gamma voltage Vgh: high potential gate drive voltage V gl: low potential gate drive voltage VIN: Input power V mod: modulation control voltage V mod1: first modulation control voltage V mod2: second modulation control voltage V ref: reference voltage V sen: sensing voltage V ss: low potential power supply voltage V ss_mod: low voltage modulation voltage V touch: touch driving voltage

Claims

1. An embedded touch display device, comprising: One substrate; A transistor forming layer is formed on the substrate, the transistor forming layer including a semiconductor, a source electrode, a drain electrode and a gate electrode; and a light-emitting element layer is formed on the transistor forming layer, the light-emitting element layer including an anode electrode, a light-emitting layer and a cathode electrode, wherein a plurality of touch electrodes are formed in the transistor forming layer, the touch electrodes and the cathode electrode of the light-emitting element layer together form a coupling capacitor, and wherein the plurality of touch electrodes are formed on the substrate and in the transistor forming layer, and disposed on the same layer as the gate electrode or on the same layer as the source electrode and the drain electrode.

2. The embedded touch display device as described in claim 1, wherein, A cover layer is 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.

3. The embedded touch display device as described in claim 2 further includes a sensing circuit configured to sense, through the touch electrode among the plurality of touch electrodes, the capacitance change of the object capacitor and the coupling capacitor when the touch object touches the cover layer.

4. The embedded touch display device as described in claim 3, wherein, The sensing circuit includes: a first integrator configured to perform an initial integration of an output signal from the touch electrode; and a second integrator configured to perform a second integration of the integrated output signal that has been integrated by the first integrator.

5. The embedded touch display device as described in claim 4, wherein, The first integrator includes: a first operational amplifier having a first input terminal configured to receive the output signal of the 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.

6. The embedded touch display device as described in claim 5, wherein, The second integrator includes: 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; and a second feedback capacitor connected between the third input terminal and the output terminal of the first operational amplifier.

7. The embedded touch display device as described in claim 6, wherein, During the touch time, a touch driving signal with a predetermined period and amplitude is applied to the touch electrode, a low-potential modulation voltage with the same period and amplitude as the touch driving signal is applied to the cathode electrode, and a reference voltage with the same period and amplitude as the touch driving signal is applied to the second input terminal of the first operational amplifier and the fourth input terminal of the second operational amplifier.

8. The embedded touch display device as described in claim 1, wherein, The plurality of touch electrodes are formed into a single transparent electrode.

9. The embedded touch display device as described in claim 1, further comprising: A touch line is formed in the transistor formation layer, and the touch line is electrically connected to the touch electrode among the plurality of touch electrodes.

10. The embedded touch display device as described in claim 9, wherein, The touch line is formed on the same layer as the source electrode and the drain electrode of the transistor formation layer.

11. The embedded touch display device as described in claim 9, wherein, The touch line is disposed in a direction parallel to a data line and is formed on a layer different from the source electrode and the drain electrode of the transistor formation layer.

12. The embedded touch display device as described in claim 1, wherein, During the touch time, a touch drive signal with a predetermined period and amplitude is applied to the touch electrode among the plurality of touch electrodes, and a low-potential modulation voltage with the same period and amplitude as the touch drive signal is applied to the cathode electrode.

13. An embedded touch display device, comprising: A display panel includes 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 forming layer including the thin-film transistor, and forming a coupling capacitor with a cathode electrode of the light-emitting element, the cathode electrode being disposed above the plurality of touch electrodes; and a sensing circuit configured to sense a touch signal by performing an initial integration of an output signal from one of the plurality of touch electrodes and a second integration of the integrated output signal, wherein the touch electrode is formed on a substrate and in the transistor forming layer, and is disposed on the same layer as a gate electrode or on the same layer as a source electrode and a drain electrode.

14. The embedded touch display device as described in claim 13, wherein, The sensing circuit includes: a first integrator configured to perform an initial integration of the output signal from the touch electrode; and a second integrator configured to perform a second integration of the output signal integrated by the first integrator.

15. The embedded touch display device as described in claim 14, wherein, The first integrator includes: a first operational amplifier having a first input terminal configured to receive the output signal of the 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.

16. The embedded touch display device as described in claim 15, wherein, The second integrator includes: 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; and a second feedback capacitor connected between the third input terminal and the output terminal of the first operational amplifier.

17. The embedded touch display device as described in claim 16, wherein, During the touch time, a touch driving signal with a predetermined period and amplitude is applied to the touch electrode, a low-potential modulation voltage with the same period and amplitude as the touch driving signal is applied to the cathode electrode, and a reference voltage with the same period and amplitude as the touch driving signal is applied to the second input terminal of the first operational amplifier and the fourth input terminal of the second operational amplifier.

18. The embedded touch display device as described in claim 13, wherein, The display panel includes: a substrate; a transistor forming layer formed on the substrate, the transistor forming layer including a semiconductor, a source electrode, a drain electrode and a gate electrode; a light-emitting element layer formed on the transistor forming layer, the light-emitting element layer including an anode electrode, a light-emitting layer and a cathode electrode; and a cover layer formed on the light-emitting element layer, wherein when a touch object touches the cover layer, the cover layer has an object capacitor between the touch object and the cathode electrode, and wherein the plurality of touch electrodes are formed in the transistor forming layer and together with the cathode electrode of the light-emitting element layer form the coupling capacitor.

19. The embedded touch display device as described in claim 18, wherein, When the touch object touches the covering layer, the sensing circuit senses the capacitance change of the object's capacitor and the coupling capacitor through at least one integrator.

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