KR101588450B1 - Touch sensor in-cell type organic electroluminescent device and methode of fabricating the same - Google Patents

Abstract

The present invention relates to a liquid crystal display device including a plurality of pixel regions defined in a display region and including gate and data lines crossing each other, a power supply line, a switching thin film transistor connected to the gate and the data line, A touch sensor comprising: a first substrate including an organic light emitting diode; and a second transparent substrate opposed to the first substrate, the touch sensor comprising: a first electrode formed in contact with the drain electrode of the driving thin film transistor A first electrode; A buffer pattern surrounding each of the pixel regions and covering an edge of the first electrode; An organic light emitting layer formed on the first electrode in each pixel region; A second electrode formed on the entire surface of the display region on the organic light emitting layer; And a plurality of third electrodes formed on the inner surface of the second substrate, the third electrodes being spaced apart from the display area of the inner surface of the second substrate and having the same area, wherein the second electrode and the third electrode are touch sensors. Device.

Organic electroluminescent device, touch sensor, simplification, light weight, thin type

Description

TECHNICAL FIELD [0001] The present invention relates to a touch sensor in-cell type organic electroluminescent device and a method of fabricating the same,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic electroluminescent device, and more particularly, to an organic electroluminescent device having a touch sensor as an in-cell type and a method of manufacturing the same.

An organic electroluminescent device, which is one of flat panel displays (FPDs), has high luminance and low operating voltage characteristics. In addition, since it is a self-luminous type that emits light by itself, it has a large contrast ratio, can realize an ultra-thin display, can realize a moving image with a response time of several microseconds (μs), has no viewing angle limit, And it is driven with a low voltage of 5V to 15V of direct current, so that it is easy to manufacture and design a driving circuit.

An organic electroluminescent device having such characteristics is largely divided into a passive matrix type and an active matrix type. In a passive matrix type, a scan line and a signal line cross each other to form a matrix type device, The scan lines are sequentially driven with time in order to drive the scan lines. Therefore, in order to represent the required average luminance, the instantaneous luminance must be equal to the average luminance multiplied by the number of lines.

However, in the active matrix method, a thin film transistor, which is a switching element for turning on / off a pixel, is located for each pixel, and the first electrode connected to the thin film transistor is turned on / Off, and the second electrode facing the first electrode is formed on the front surface and becomes a common electrode.

In the active matrix method, the voltage applied to the pixel is charged in the storage capacitor (C _ST ), and power is applied until the next frame signal is applied. Thus, Continue to run for one screen without. Accordingly, since the same luminance is exhibited even when a low current is applied, an active matrix type organic electroluminescent device is mainly used since it has advantages of low power consumption, high definition and large size.

Hereinafter, the basic structure and operating characteristics of such an active matrix organic electroluminescent device will be described in detail with reference to the drawings.

1 is a circuit diagram of one pixel of a general active matrix organic electroluminescent device.

As shown, one pixel of the active matrix type organic electroluminescent device includes a switching thin film transistor STr, a driving thin film transistor DTr, a storage capacitor StgC, and an organic electroluminescent diode E ).

That is, a gate line GL is formed in a first direction and a data line DL is formed in a second direction intersecting the first direction to define a pixel region P, A power supply line PL for applying a power supply voltage is formed.

A switching thin film transistor STr is formed at the intersection of the data line DL and the gate line GL and a driving thin film transistor DTr electrically connected to the switching thin film transistor STr is formed have.

At this time, the driving thin film transistor DTr is electrically connected to the organic light emitting diode E. That is, the first electrode, which is one terminal of the organic electroluminescent diode E, is connected to the drain electrode of the driving thin film transistor DTr, and the second electrode, which is the other terminal, is connected to the power supply line PL. At this time, the power supply line (PL) transfers the power supply voltage to the organic light emitting diode (E). A storage capacitor StgC is formed between the gate electrode and the source electrode of the driving thin film transistor DTr.

Therefore, when a signal is applied through the gate line GL, the switching thin film transistor STr is turned on and the signal of the data line DL is transmitted to the gate electrode of the driving thin film transistor DTr, The thin film transistor DTr is turned on so that light is output through the organic light emitting diode E. At this time, when the driving thin film transistor DTr is turned on, the level of a current flowing from the power supply line PL to the organic light emitting diode E is determined, and thereby the organic light emitting diode E The storage capacitor StgC can maintain a constant gate voltage of the driving thin film transistor DTr when the switching thin film transistor STr is turned off, The level of the current flowing through the organic light emitting diode E can be kept constant until the next frame even if the switching thin film transistor STr is turned off.

2 is a schematic cross-sectional view of a conventional organic electroluminescent device.

The first and second substrates 10 and 70 are disposed opposite to each other and the edge portions of the first and second substrates 10 and 70 are sealed by a seal pattern 80 A driving thin film transistor DTr is formed on the first substrate 10 for each pixel region P and a first electrode 47 is formed in connection with each of the driving thin film transistors DTr An organic light emitting layer 55 including a light emitting material corresponding to red, green and blue colors is formed on the first electrode 47. An organic light emitting layer 55 including a light emitting material corresponding to red, And a second electrode 58 is formed on the front surface. At this time, the first and second electrodes 47 and 58 serve to apply an electric field to the organic light emitting layer 55.

The second electrode 47 and the second substrate 58 formed on the first substrate 10 are separated from each other by a predetermined distance by the seal pattern 80 described above.

3 is a cross-sectional view of a pixel region including a conventional thin film transistor of a conventional organic electroluminescent device.

A semiconductor layer 13 composed of a first region 13a of pure polysilicon and a second region 13b doped with an impurity, a gate insulating film 16, and a gate electrode (not shown) are formed on the first substrate 10, An interlayer insulating film 23 having a semiconductor layer contact hole 25 exposing the first region 13 and a second region 13b and source and drain electrodes 33 and 36 are sequentially stacked to form a driving thin film transistor DTr, And the source and drain electrodes 33 and 36 are connected to a power supply line (not shown) and the organic light emitting diode E, respectively.

The organic electroluminescent diode E includes a first electrode 47 and a second electrode 58 opposed to each other with the organic light emitting layer 55 interposed therebetween. The first electrode 47 is formed in contact with one electrode of the driving thin film transistor DTr for each pixel region P and the second electrode 58 is formed over the organic light emitting layer 55 .

Further, the second substrate 70 is configured to encapsulate the first substrate 10 having the above-described structure.

The first electrode 47 may be formed of indium-tin-oxide (ITO) or indium-tin-oxide (ITO), which is a transparent conductive material having a high work function value to serve as an anode electrode when the driving thin film transistor DTr is p- - zinc (IZO), and the second electrode 58 is made of a metal material having a low work function value, for example, aluminum (Al) so as to serve as a cathode electrode.

On the other hand, in recent years, a product in which a touch sensor is incorporated in a mobile phone, a PDA or a notebook which can be carried by a person has been attracting much attention from users, and organic electroluminescent devices are also used as display devices in all of these products. A product with a touch sensor attached to the foot is being released recently.

4 is a schematic cross-sectional view of an organic electroluminescent device to which a conventional touch sensor is attached.

The organic electroluminescent device 2 having the conventional touch sensor includes a first substrate 10 on which a switching and driving thin film transistor (not shown, DTr) and an organic electroluminescent diode E are formed, A first panel PA1 composed of a second substrate 70 for the first panel PA1 and a touch first electrode 82 formed on the lower and upper portions of the first panel PA1 via a first adhesive layer 72, A protection layer formed on the outer surface of the third substrate 80 via the third substrate 80 and the second adhesive layer 92 constituted by the touch second electrode 86 having a plurality of bar- And a second panel PA2 including a sheet 90. [

Therefore, it can be understood that the organic electroluminescent device 2 including the conventional touch sensor is made up of three substrates 10, 70, and 90 although the protective sheet 90 is omitted.

At this time, the substrates 10, 70, and 90 used in the organic electroluminescent device 2 are mainly glass substrates having transparent characteristics, and three organic EL devices having a touch sensor (TS) When the electroluminescent element 2 is constituted, the thickness of the electroluminescent element 2 becomes very large, and the weight of the electroluminescent element 2 becomes relatively heavy, thereby causing a problem that the display device is backed by a thin and light trend.

In addition, since a separate process for forming the touch sensor TS has to be performed, the process becomes complicated.

It is an object of the present invention to provide an organic electroluminescent device having a lightweight thin touch sensor by minimizing the use of a substrate.

Another object of the present invention is to reduce the manufacturing cost by simplifying the manufacturing process by minimizing the components for implementing the touch sensor.

According to an aspect of the present invention, there is provided a touch sensor type organic electroluminescent device including a plurality of pixel regions defined in a display region, gate and data lines crossing each other, power supply lines, A touch sensor type organic electroluminescent device including a switching thin film transistor connected to a switching thin film transistor, a first substrate including a driving thin film transistor connected to the switching thin film transistor and an organic light emitting diode, and a second transparent substrate facing to the first thin film transistor, A first electrode formed in each pixel region in contact with a drain electrode of the driving thin film transistor; A buffer pattern surrounding each of the pixel regions and covering an edge of the first electrode; An organic light emitting layer formed on the first electrode in each pixel region; A second electrode formed on the entire surface of the display region on the organic light emitting layer; And a plurality of third electrodes spaced apart from the display area of the inner surface of the second substrate and having the same area, and the second electrode and the third electrode form a touch sensor.

At this time, an insulating layer made of an inorganic insulating material or an organic insulating material is formed between the first substrate and the second substrate, or a face seal for bonding the first and second substrates is formed, or an inert gas layer is formed And the insulating layer, the face seal, and the inert gas layer together with the second electrode and the third electrode constitute a first capacitor constituting a touch sensor.

In addition, the touch sensor operates to detect a change in the capacitance of the first capacitor due to a change in spacing between the first and second substrates due to a pressure externally applied. In this case, The device is characterized in that it is driven by a top emission type or a bottom emission type.

The organic electroluminescent device may be driven by an upper emission type, and the touch sensor may include a finger of the user, the second substrate, and the third electrode when the finger of the user directly contacts the surface of the second substrate. Element, and is configured to detect a change in capacitance of the capacitor due to the presence or absence of the formation of the second capacitor.

In the case of driving by the top emission type, a reflection plate formed of any one of aluminum (Al), aluminum alloy (AlNd) and silver (Ag) having excellent reflection efficiency is formed under the first electrode, (ITO) or indium-zinc-oxide (IZO) which is a transparent conductive material having a relatively high work function value so as to serve as an anode electrode, and the second electrode serves as a cathode electrode (ITO), which is a transparent conductive material, is formed of any one of aluminum (Al), aluminum alloy (AlNd) and silver (Ag) Or indium-zinc-oxide (IZO).

In addition, a transparent conductive material layer made of a transparent conductive material is formed on the second electrode.

The organic light emitting layer is composed of red, green, and blue organic light emitting materials. Red, green, and blue organic light emitting layers are sequentially formed in each pixel region to emit red, green, and blue light.

In addition, a hole injection layer and a hole transporting layer are formed between the first electrode and the organic light emitting layer, and an electron transporting layer is formed between the organic light emitting layer and the second electrode. An electron injection layer is formed.

The touch sensor type organic electroluminescent device according to the present invention includes a first substrate on which an organic light emitting diode is formed and a second substrate on which encapsulation is performed, It is effective to implement thinning by reducing the use of one substrate compared to that of the other substrate.

Further, by using the second electrode of the organic light emitting diode as the touch first electrode of the touch sensor, components for implementing the touch sensor can be minimized, simplifying the process, and further reducing the manufacturing cost.

Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the drawings.

5 is a cross-sectional view of a touch sensor type insensitive-type organic electroluminescent device according to an embodiment of the present invention. Here, for convenience of description, a region where a switching thin film transistor is to be formed is defined as a switching region, and a region where a driving thin film transistor is to be formed is defined as a driving region.

As shown in the drawing, the touch sensor type insensitive organic EL device 101 according to the present invention has a structure in which some of the components constituting the driving and switching thin film transistor DTr (not shown), the organic light emitting diode E, And a second substrate 170 for encapsulation in which a first substrate 110 is formed and another part of the components constituting the touch sensor are formed.

First, the structure of the first substrate 110 will be described.

Each pixel region P on the first substrate 110 is made of pure polysilicon and the central portion thereof includes a first region 113a forming a channel and a first region 113b doped with impurities at high concentration on both sides of the first region 113a. And a semiconductor layer 113 composed of two regions 113b are formed. A buffer layer (not shown) made of an inorganic insulating material such as silicon oxide (SiO ₂ ) or silicon nitride (SiNx) is formed on the entire surface between the semiconductor layer 113 and the first substrate 110, May be further formed. The buffer layer (not shown) prevents the deterioration of the characteristics of the semiconductor layer 113 due to the release of alkali ions from the inside of the first substrate 110, which is a glass material when the semiconductor layer 113 is crystallized.

A gate insulating layer 116 is formed on the entire surface of the semiconductor layer 113 and a gate electrode 116 corresponding to the first region 113a of the semiconductor layer 113 is formed on the gate insulating layer 116. [ 120 are formed. The gate insulating layer 116 is connected to a gate electrode (not shown) for forming a switching thin film transistor (not shown) and extends in one direction to form a gate wiring (not shown).

In addition, an interlayer insulating film 123 is formed on the entire surface of the gate electrode 120 and the gate wiring (not shown). The interlayer insulating layer 123 and the gate insulating layer 116 under the semiconductor layer contact hole 125 expose the second regions 113b located on both sides of the first region 113a .

A data line (not shown) is formed on the interlayer insulating layer 123 including the semiconductor layer contact hole 125 to define a pixel region P intersecting the gate line (not shown) Wiring (not shown) is formed. The source and drain electrodes 113 and 114 are in contact with the second region 113b which are spaced apart from each other in the driving region DA and the switching region (not shown) above the interlayer insulating layer 123 and exposed through the semiconductor layer contact hole 125, Drain electrodes 133 and 136 are formed. A semiconductor layer 113 including the source and drain electrodes 133 and 136 and a second region 113b contacting the electrodes 133 and 136 and a gate electrode The insulating film 116 and the gate electrode 120 constitute a driving thin film transistor DTr and a switching thin film transistor (not shown), respectively. At this time, the switching thin film transistor (not shown) is electrically connected to the driving thin film transistor DTr, a gate wiring (not shown) and a data wiring (not shown). The data line (not shown) is connected to a source electrode (not shown) of the switching thin film transistor (not shown).

At this time, the driving and switching thin film transistor DTr (not shown) forms a p-type or n-type thin film transistor according to impurities doped in the second region 113b. In the case of the p-type thin film transistor, the second region 113b is formed by doping a group III element such as boron (B), and holes are used as carriers.

The first electrode 147 connected to the drain electrode 136 of the driving thin film transistor DTr functions as an anode or a cathode electrode depending on the type of the driving thin film transistor DTr. In the exemplary embodiment of the present invention, the first electrode 147 connected to the driving thin film transistor DTr functions as an anode electrode.

On the other hand, a first passivation layer 140 is formed over the driving and switching thin film transistor DTr (not shown). A drain contact hole 143 is formed in the first passivation layer 140 to expose the drain electrode 136 of the driving TFT DTr.

A gate electrode (not shown) of the switching thin film transistor (not shown) is connected to the gate wiring (not shown), and a source electrode (not shown) of the switching thin film transistor And is connected to the data line (not shown).

The first passivation layer 140 having the drain contact hole 143 is in contact with the drain electrode 136 of the driving thin film transistor DTr through the drain contact hole 143, A first electrode 147 is formed for each region P. At this time, the first electrode may have a different structure depending on whether the organic electroluminescent device is a top emission type or a bottom emission type.

Although not shown in the figure, in the case of the top emission type, the first electrode 147 may have a bilayer structure or a reflection plate (not shown) may be provided under the first electrode 147 to improve luminous efficiency. In this case, when the first electrode 147 has a double layer structure, the upper layer (not shown) serves as an anode electrode and the lower layer (not shown) serves as a reflective plate.

That is, an upper layer (not shown) of the first electrode 147 may be formed of a transparent conductive material having a relatively large work function value such as indium-tin-oxide (ITO) or indium-zinc- And a lower layer (not shown) of the first electrode 147 is made of a metal material having excellent reflection efficiency, for example, aluminum (Al) or silver (Ag) The light emitted from the organic light emitting layer 155 may be reflected upward to improve the light emitting efficiency.

When the first electrode 147 is formed as a single layer structure as shown in the drawing, a reflection plate (not shown) may be further formed under the first electrode 147 as a metal material having excellent reflection efficiency.

On the other hand, when the organic electroluminescent device is a bottom emission type, the first electrode is formed as a transparent conductive material in a single layer structure, and in this case, no reflection plate is formed.

Next, a buffer pattern 150 is formed on the boundary of each pixel region P so as to overlap the rim of the first electrode 147 in the form of surrounding each pixel region P above the first electrode 147 have.

An organic light emitting layer 155 is formed on the first electrode 147 in each pixel region P surrounded by the buffer pattern 150. On the organic light emitting layer 155, The first substrate is completed by forming the second electrode 158 made of a metal material having a relatively low work function value to serve as an electrode. At this time, the first and second electrodes 147 and 158 and the organic light emitting layer 155 formed therebetween form an organic light emitting diode (E).

At this time, the structure of the second electrode may be changed depending on whether the organic electroluminescent device 101 is a top emission scheme or a bottom emission scheme.

In the case of the top emission type, since light emitted from the organic light emitting layer 155 must be transmitted, the second electrode 158 is formed of a metal material having a relatively low work function value such as aluminum (Al), aluminum alloy (AlNd) (Not shown) is formed to have a thickness of about 10 to 50 angstroms so that light can be transmitted through any one of Ag, Ag, and Ag, and an upper layer (not shown) having a thickness of about 500 to 2000 angstroms Layer structure.

The second electrode 158 may be formed of any one of aluminum (Al), aluminum alloy (AlNd), and silver (Ag), which are relatively low work function values, And has a thickness of about 2,000 ANGSTROM.

Although not shown in the drawing, the light emitting efficiency of the organic light emitting layer 155 is improved between the first electrode 147 and the organic light emitting layer 155 and between the organic light emitting layer 155 and the second electrode 158, A first luminescence compensation layer (not shown) and a second luminescence compensation layer (not shown) having a multilayer structure may be further formed. At this time, the first emission compensation layer (not shown) of a plurality of layers is sequentially stacked from the first electrode 147, and is composed of a hole injection layer and a hole transporting layer, 2 emission compensation layer (not shown) is composed of an electron transporting layer and an electron injection layer from the organic light emitting layer 155. The first emission compensation layer (not shown) and the second emission compensation layer (not shown) of the multi-layer structure may be formed on the entire surface of the display region or may be formed separately for each pixel region P have.

In the meantime, the second substrate 170, which is most characteristic of the present invention, encapsulates the first substrate 110 having the above-described configuration, has the same area and size (corresponding to the display area of the first substrate 110) And a plurality of third electrodes 173 are formed at a predetermined interval in a matrix form. In this case, the third electrode 173 is made of a transparent conductive material when driven by a top emission type, and is formed of a transparent conductive material or a metal material when driven by a bottom emission type.

The third electrode 173 of the second substrate 170 for encapsulation and the second electrode 158 of the organic electroluminescent diode E formed on the first substrate 110 may be a sensing electrode, Thereby forming a device TS.

At this time, although not shown in the drawing, between the first electrode 110 and the second electrode 170, more precisely between the second electrode 158 and the third electrode 173, an inorganic insulating material or an insulating material (Not shown), or a face seal (not shown) for attaching the first substrate 110 and the second substrate 170 together may be further provided, and further an inert gas layer (not shown) may be formed It is possible. In this case, the dielectric layer (not shown), the phase seal (not shown), and the inert gas layer (not shown) are used as the dielectric layer 177, and the second electrode 158 and the third electrode 173, C1). At this time, the capacitor composed of the second and third electrodes 158 and 173 and the dielectric layer 177 operates as a sensing element TS.

6A and 6B are diagrams illustrating a sensing operation of the touch sensor in the touch sensor type insensitive-type organic electroluminescent device according to an embodiment of the present invention. FIG. 6A shows an operation state before sensing is performed, As shown in Fig.

When no touch occurs in the display area of the organic electroluminescent device 101, the second electrode 158 formed on the front surface and the third electrode 173 formed in the patterned state and the dielectric layer 177 are formed, The sensing elements TS constituted by the first substrate 110 and the second substrate 170 are identical to each other because the areas of the patterned third electrodes 173 are the same and the spacing between the first substrate 110 and the second substrate 170 is the same It can be seen that the plurality of sensing elements TS all have the same storage capacitance. At this time, the capacitance C1 of the sensing element TS largely depends on a capacitance (hereinafter referred to as an area capacitance Cp) due to the area of the third electrode 173 among the elements constituting the sensing element TS, And a capacitance due to the thickness of the dielectric layer 177 (hereinafter referred to as a gap capacitance Cg). Accordingly, when no touch is generated in the organic electroluminescent device 101, the third electrodes 173 have the same area and the spacing between the first and second substrates 110 and 170 is constant. Therefore, It can be understood that all of the elements TS are in a state of having a capacitance equivalent to the same size.

Meanwhile, when the display area of the organic light emitting diode 101 is touched by the user and a predetermined pressure is partially applied thereto, the pressure applied portion may be applied between the first substrate 110 and the second substrate 170 The spacing of the spacing is changed. In this case, since the gap capacitance Cg changes due to a change in the thickness of the dielectric layer 177 of the sensing element TS, the capacitance C1 of the sensing element TS is finally changed, And the capacitance of the sensing element (TS).

Accordingly, the organic electroluminescent device 101 can be realized by sensing a touch without a separate touch panel by such a sensing operation that senses a portion where a change in the storage capacitance occurs.

The organic electroluminescent device according to an embodiment of the present invention having the above-described constitution and operation includes a sensing element (TS) that operates in response to a pressure applied when a touch is made, so that the first and second substrates The organic light emitting device 101 can be operated by touching regardless of the top emission type and the bottom emission type if the condition that a pressure enough to cause a change in thickness between the upper emission type and the lower emission type is satisfied.

On the other hand, as a modified example, the organic electroluminescent device having the above-described configuration is similar to the organic electroluminescent device shown in FIG. 7 (the sensing operation of the touch sensor of the touch sensor type insensitive-type organic electroluminescent device according to the modification of the embodiment of the present invention) The sensing element TS senses another capacitance change occurring at the time of touching in addition to a sensing method due to a change in the spacing between the first and second substrates 110 and 170 It may also work.

That is, when the user touches the display area using the user's finger, a very small current flows through the human body, so that the fourth electrode 195 is used as the fourth substrate 195, and the second substrate 170 is used as the second dielectric layer, And the third electrode has another storage capacitance (hereinafter referred to as finger storage capacitance Cf).

Therefore, when the display area of the second substrate 170 is touched by using a finger when driving by the top emission type, a finger charging capacity Cf naturally occurs even if no pressure is applied by applying a force, It is possible to know whether or not it is touched because it causes a change in the magnitude of the entire capacitive capacitance (C1 + Cf) at the generated portion, and the touched operation is performed. When no touch occurs, all the touch sensors TS formed in the entire display area have capacitances C1 of the same size. When a touch occurs, the finger storage capacitance Cf is added to the touch generated area, A change in the magnitude of the total charge capacity (C1 + Cf) occurs at the portion where the voltage is applied, thereby sensing whether or not the touch occurs.

An organic electroluminescent device according to an embodiment of the present invention having the above-described structure includes a protective sheet, a substrate, and a touching material, which are compared to a conventional organic electroluminescent device having an additional touch sensor in an add- One electrode and the dielectric layer can be omitted. Accordingly, the organic electroluminescent device according to the present invention is thinned and lightened by omitting the protective sheet, the single substrate and the two material layers, and the process simplification can be realized by omitting two material layers.

1 is a circuit diagram of a pixel of a general active matrix organic electroluminescent device.

2 is a schematic cross-sectional view of a conventional organic electroluminescent device.

3 is a cross-sectional view of one pixel region including a driving thin film transistor of a conventional top emission type organic electroluminescent device.

4 is a schematic cross-sectional view of an organic electroluminescent device to which a conventional touch sensor is attached.

5 is a cross-sectional view of a touch sensor type insoluble organic electroluminescent device according to an embodiment of the present invention.

6A to 6B are diagrams illustrating the operation of a touch sensor in a touch sensor type organic electroluminescent device according to the present invention.

7 is a diagram illustrating a sensing operation of a touch sensor of a touch incell type organic electroluminescent device according to a modification of the embodiment of the present invention.

Description of the Related Art

101: touch sensor Insel type organic electroluminescent device

110: first substrate 113: semiconductor layer

113a: first region 113b: second region

116: gate insulating film 120: gate electrode (of the driving thin film transistor)

123: interlayer insulating film 125: semiconductor layer contact hole

133: source electrode (of the driving thin film transistor)

136: drain electrode (of the driving thin film transistor)

140: first protective layer 143: drain contact hole

147: first electrode 150: buffer pattern

155: organic light emitting layer 158: second electrode

170: second substrate 173: third electrode

177:

DA: driving region E: organic light emitting diode

P: pixel area TS: touch sensor

Claims (9)

A switching thin film transistor connected to the gate thin film transistor and the data thin line, a driving thin film transistor connected to the switching thin film transistor, and an organic light emitting diode And a second transparent substrate opposed to the first substrate. The touch sensor includes: A first electrode disposed in each pixel region in contact with a drain electrode of the driving thin film transistor; A buffer pattern surrounding each of the pixel regions and disposed to cover an edge of the first electrode; An organic light emitting layer disposed over the first electrode in each of the pixel regions; A second electrode disposed on the entire surface of the display region on the organic light emitting layer; And a plurality of third electrodes disposed on the inner surface of the second substrate and corresponding to the display region of the first substrate, And the touch sensing is performed by detecting a change in the distance between the second and third electrodes. The method according to claim 1, An insulating layer made of an inorganic insulating material or an organic insulating material is disposed between the second and third electrodes, a face seal for bonding the first and second substrates is disposed, an inert gas layer is disposed, Layer, a face seal, or an inert gas layer, and the second and third electrodes constitute a first capacitor. 3. The method of claim 2, A touch sensor according to any one of claims 1 to 3, wherein the distance between the second electrode and the third electrode is reduced by a pressure applied from the outside, and the touch is sensed by increasing the capacitance of the first capacitor. The method of claim 3, Wherein the organic electroluminescent device is driven by a top emission type or a bottom emission type. 3. The method of claim 2, The organic electroluminescent device is driven by a top emission type. When the user's finger touches the surface of the second substrate directly, the organic electroluminescent device forms a second capacitor with the user's finger, the second substrate, and the third electrode as constituent elements And the touch sensing is performed according to the presence or absence of the capacitive capacitance of the second capacitor. 5. The method of claim 4, When driving by the top emission type, And a reflection plate disposed under the first electrode, The first and third electrodes are made of indium-tin-oxide (ITO) or indium-zinc-oxide (IZO) Wherein the second electrode and the reflection plate are made of aluminum (Al), aluminum alloy (AlNd), or silver (Ag). The method according to claim 6, And a transparent conductive material layer made of a transparent conductive material is formed on the second electrode. The method according to claim 1, The organic light emitting layer is composed of red, green, and blue organic light emitting materials. Red, green, and blue organic light emitting layers are sequentially formed in each pixel region to emit red, green, and blue light. device. The method according to claim 1, A hole injection layer and a hole transporting layer are formed between the first electrode and the organic light emitting layer, Wherein an electron transporting layer and an electron injection layer are formed between the organic light emitting layer and the second electrode.

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