KR101476434B1 - Organic Light Emitting Diode Panel and Touch Screen System comprising the same - Google Patents

Abstract

The present invention relates to a liquid crystal display device including first and second scan lines and data lines; A switching transistor that is turned on by a first scan signal applied from the first scan line and transmits a data signal applied from the data line; A capacitor for receiving a data signal from the switching transistor and storing the data signal; A driving transistor which is turned on by the data signal and generates a driving current corresponding to the data signal; An organic light emitting diode emitting light by the driving current; And a sensing transistor connected between the organic light emitting diode and the driving transistor and being turned on by a second scan signal applied from the second scan line to sense a change amount of the driving current, An organic electroluminescence panel and a touch screen system including the same are provided.

Organic electroluminescent display panel, touch, sensing

Description

[0001] The present invention relates to an organic electroluminescence panel and a touch screen system including the organic electroluminescence panel,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic electroluminescent panel and a touch screen system including the same.

2. Description of the Related Art In recent years, the importance of flat panel displays (FPDs) has been increasing with the development of multimedia. In response to this, various kinds of devices such as a liquid crystal display (LCD), a plasma display panel (PDP), a field emission display (FED), an organic light emitting display A planar display of a branch has been put into practical use.

Planar displays are becoming smaller and more functional, and touch screens are often used with a variety of planar displays as described above.

That is, the conventional touch screen is manufactured as a separate device and joined to the surface of the panel by mechanical mounting means.

However, the combination of the panel and the mechanical mounting means of the touch screen not only increases the number of parts, weight and manufacturing cost, but also increases the thickness of the display. Further, when there are a plurality of portions to be touched, that is, when the touched portions are multi-touched, the positions are not accurately detected.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide an organic electroluminescence panel in which a plurality of transistors are used as a driving device, and a touch sensing structure is built in the organic electroluminescence panel, And a touch screen system including the organic electroluminescence panel.

Other technical objects to be achieved by the present invention are not limited to the above-mentioned technical problems, and other technical subjects which are not mentioned can be understood from the following description in order to clearly understand those skilled in the art to which the present invention belongs .

According to an aspect of the present invention, there is provided a display device including first and second scan lines and a data line; A switching transistor that is turned on by a first scan signal applied from the first scan line and transmits a data signal applied from the data line; A capacitor for receiving a data signal from the switching transistor and storing the data signal; A driving transistor which is turned on by the data signal and generates a driving current corresponding to the data signal; An organic light emitting diode emitting light by the driving current; And a sensing transistor connected between the organic light emitting diode and the driving transistor and being turned on by a second scan signal applied from the second scan line to sense a change amount of the driving current, An organic electroluminescent panel is provided.

The present invention also relates to an organic electroluminescence panel comprising a plurality of subpixels; A readout IC electrically connected to the organic electroluminescence panel and measuring a change amount of a driving current flowing in the organic electroluminescence panel; A converter for converting a signal output from the lead-out unit into an electrical signal; And a video signal processing unit receiving a signal from the transducer and recognizing the external touch position, wherein the sub-pixel includes first and second scan lines and a data line, a first scan signal applied from the first scan line, A switching transistor that is turned on by the data line and transfers a data signal applied from the data line, a capacitor that stores the data signal, a driving current that is turned on by the data signal, An organic light emitting diode which emits light by the driving current and a second scan signal which is connected between the organic light emitting diode and the driving transistor and is turned on by a second scan signal applied from the second scan line, A touch screen system including a sensing transistor for sensing The ball.

The organic electroluminescent panel and the touch screen system including the organic electroluminescent panel according to the present invention have a touch sensor incorporated in an organic electroluminescent panel using a plurality of transistors, thereby eliminating the need for a separate sensor device and realizing a lightweight thin display And since the touch sensor is formed by the same process as the manufacturing process of the organic electroluminescence panel, the manufacturing time and the manufacturing cost are reduced.

In addition, a signal detected through the touch sensor can be converted into a size and an image form, so that the user can grasp the touch point and the strength of the touch.

In addition, since each sub-pixel is provided with a touch sensor, sensing for multi-touch is effective.

Hereinafter, an organic electroluminescent panel and a touch screen system including the same according to embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram illustrating a touch screen system including an organic electroluminescent panel according to an embodiment of the present invention.

1, a touch screen system according to an exemplary embodiment of the present invention includes an organic electroluminescent module 200, a digital board 300, and a system 400 including an organic electroluminescent panel 100. ).

The organic electroluminescent panel 100 includes a display unit including a plurality of sub-pixels.

The organic electroluminescent panel 100 includes a scan driver 210, a data driver 220 and an organic electroluminescent panel 100 for applying a driving signal to the organic electroluminescent panel 100, And is connected to a readout IC (Readout IC) 230 for measuring a signal. The organic light emitting module 200 includes the organic electroluminescent panel 100 and the external scan driver 210, the data driver 220, and the lead-out unit 230.

The digital board 300 is connected to the organic electroluminescent module 200 and receives a signal output from the output unit 230 to perform signal processing.

That is, the digital board 300 includes a timing controller for applying a control signal for controlling the scan driver 210 and the data driver 220, an analog-to-digital converter (ADC) for converting the signals output from the lead- An analog to digital converter (ADC), and a display signal processor (DSP).

The digital board 300 is connected to a system 400 such as an external computer. The signal processed in the video signal processor of the digital board 300 is transmitted to the system 400 through the system interface, and the system 400 can perform the corresponding operation.

Hereinafter, the structure of the organic electroluminescence panel 100 according to one embodiment of the present invention will be described in detail with reference to FIGS. 2 and 3. FIG.

FIG. 2 is an equivalent circuit diagram illustrating an organic electroluminescent panel according to an embodiment of the present invention, and FIG. 3 is a timing diagram illustrating an operation of the organic electroluminescent panel according to an embodiment of the present invention.

2, the organic electroluminescent panel according to the embodiment of the present invention includes a first scan line S10 and a second scan line S11 arranged in one direction, a first scan line S10, A sub-pixel region (sub-pixel) is formed by the intersection of the first scan line S10, the second scan line S11, and the data line Dm. Is defined.

That is, the sub-pixel area is defined by two scan lines S10 and SS11 and one data line Dm. In each sub-pixel area, A driving transistor T2, a capacitor Cst, an organic light emitting diode OLED, and a sensing transistor T3.

The switching transistor T1 is connected to the first scan line S10 and the data line Dm and is turned on or turned off according to a first scan signal applied through the first scan line S10. - Turn-off.

The gate electrode of the switching transistor T1 is connected to the first scan line S10 and the first electrode and the second electrode of the switching transistor T1 are connected to the gate of the data line Dm and the gate of the driving transistor T2, Electrode.

One of the electrodes of the capacitor Cst is connected between the first electrode of the switching transistor Tl and the gate electrode of the driving transistor T2 and the other electrode thereof is connected to the second electrode of the driving transistor T2 and the power source voltage VDD And temporarily stores the data signal applied through the data line Dm and provides the data signal to the driving transistor T2 when the switching transistor T1 is turned on.

The driving transistor T2 receives the data signal stored in the capacitor Cst according to the switching operation of the switching transistor T1 and generates a driving current to supply the driving current to the organic light emitting diode OLED.

The gate electrode of the driving transistor T2 is connected to the second electrode of the switching transistor T1. The first electrode of the driving transistor T2 is connected to the organic light emitting diode OLED. And the second electrode of the driving transistor T2 is electrically connected to the power source voltage VDD.

Accordingly, the driving transistor T2 is turned on by the data signal stored in the capacitor Cst and generates a driving current corresponding to the difference between the data signal applied from the capacitor Cst and the power source voltage Vgnd.

The organic light emitting diode OLED emits light by the driving current of the driving transistor T2. Here, the organic light emitting diode OLED has one end connected to the first electrode of the driving transistor T2 and the other end connected to the ground voltage Vgnd, so that a positive bias is applied.

The sensing transistor T3 senses the amount of the driving current generated in the driving transistor T2. More specifically, when light emitted through the organic light emitting diode OLED by an external touch is incident on the driving transistor T2, when light is incident on the channel region of the driving transistor T2, The amount is temporarily increased. That is, during one frame, the driving transistor generates the same amount of driving current by the data signal stored in the capacitor. When light is irradiated to the driving transistor by the touch, the amount of driving current may change. Therefore, the sensing transistor T3 senses the amount of change of the driving current that changes due to the irradiation of the light, and makes it possible to determine whether the external touch is made through the amount of change of the driving current.

The gate electrode of the sensing transistor T3 is connected to the second scan line S11 and the first electrode of the sensing transistor T3 is connected between the organic light emitting diode OLED and the first electrode of the driving transistor T2. And the second electrode of the sensing transistor T3 is connected to a readout line. Accordingly, the sensing transistor T3 is turned on by the second scan signal applied through the second scan line S11. At this time, the driving current of the driving transistor T2 is coupled to the second electrode of the sensing transistor through the second electrode of the sensing transistor (230 in FIG. 1).

3, the power supply voltage VDD and the ground voltage Vgnd are applied to both sides of the organic light emitting diode OLED, and the first scan signal Vgate1 And at the same time, the data signal Vdata is applied through the data line Dm. After the first scan signal (Vgate1) is applied, the second scan signal (Vgate2) is applied through the second scan line (S11), so that the light emission period and the sensing period exist at the same time.

The driving method of the organic light emitting display panel according to an embodiment of the present invention will now be described in detail. When the first scan signal Vgate1 is applied, the switching transistor T1 is turned on by the first scan signal Vgate1, Is turned on. At this time, the data signal Vdata applied through the data line Dm is applied, which is stored in the capacitor Cst. The data signal Vdata is supplied to the driving transistor T2 to drive the driving transistor T2. Thereafter, a driving current generated in the driving transistor T2 is supplied to the organic light emitting diode OLED to emit light.

After the first scan signal Vgate1 is applied and the second scan signal Vgate2 applied through the second scan line S11 is applied, the sensing transistor T3 senses the amount of the driving current generated in the driving transistor.

That is, during the period t2 during which the second scan signal Vgate2 is applied, the sensing transistor T3 is turned on by the second scan signal Vgate2, and the driving current generated in the driving transistor T2 is sensed And flows to the lead-out portion (230 in FIG. 1) through the transistor.

At this time, if no external touch is generated, the current output through the sensing transistor T3 is almost constant for one frame, and when a touch is generated from outside, the current output through the sensing transistor T3 rapidly increases , Whereby it is possible to judge whether or not the touch is made.

4 is a circuit diagram showing a lead-out unit of a touch screen system according to an embodiment of the present invention.

The lead-out unit 230 included in the touch screen system according to the embodiment of the present invention includes an amplifier 232 for amplifying a signal output from the sensing transistor T3 of the organic electroluminescence panel 100, And capacitors C1 and C2.

In this case, the (-) input terminal of the operational amplifier is connected to the first capacitor C1 connected to the lead-out line, and the (+) input terminal of the operational amplifier 232 is connected to the Is connected to the reference voltage Vref and the output terminal of the operational amplifier is connected to the second capacitor C2 connected to the negative input terminal.

Therefore, the lead-out unit 230 configured as described above detects the signal output from the sensing transistor (T3 in FIG. 2) and amplifies the detected signal to grasp whether or not the signal is touched.

The output signal Vout amplified through the lead-out section 230 is calculated by the following equation.

Here, Vin is a voltage output from the sensing transistor corresponding to the n-th sub-pixel.

The organic electroluminescent panel and the touch screen system including the organic electroluminescent panel according to an embodiment of the present invention configured as described above have a structure for realizing an image image and a structure for sensing a touch on the same plane.

Accordingly, the organic electroluminescent panel according to the embodiment of the present invention has a touch sensing function, low manufacturing cost, and a small panel thickness and a small thickness. In addition, since the organic electroluminescent panel according to the embodiment of the present invention has a touch sensing function in each sub-pixel over the entire surface of the panel, it is possible to sense multi-touch when a touch occurs at various points.

FIG. 5 is a schematic cross-sectional view for explaining the operation of the organic electroluminescent panel according to an embodiment of the present invention when touching. FIG. 6 is a cross- FIG. 5 is a graph showing current characteristics according to the case where the light is irradiated and the case where the light is not irradiated. FIG.

5, an organic electroluminescent panel according to an exemplary embodiment of the present invention includes a switching transistor (not shown), a driving transistor T2, and a sensing transistor (not shown) formed on a substrate 110 And the cover substrate 130 is adhered to the uppermost end and encapsulated.

The dual driving transistor T2 includes a gate electrode 121, a gate insulating film 122, a semiconductor layer 123, a first electrode 124a, and a second electrode 124b on a substrate 110. Here, the first electrode 124a and the second electrode 124b may be either a source electrode or a drain electrode.

A scan line (not shown) branched from a part of the gate electrode 121 may be formed on the same plane as the gate electrode 121 formed on the predetermined substrate 110.

A gate insulating layer 122 is formed on the gate electrode 121 and a semiconductor layer 123 made of polysilicon doped with an undoped amorphous silicon material or an impurity in a predetermined region is formed on the gate insulating layer 122 . A region corresponding to the gate electrode 121 on the semiconductor layer 123 is used as a channel portion. The first electrode 124a and the second electrode 124b, that is, the source electrode and the drain electrode are formed so as to expose a region used as a channel portion on the semiconductor layer 123 and to be spaced apart from each other.

Although not shown, a data line extended from the second electrode 124b may be formed on the same plane as the second electrode 124b.

When the semiconductor layer 123 is made of amorphous silicon, an ohmic contact layer (not shown) is formed on the interface between the first electrode 124a and the second electrode 124b and the semiconductor layer 123, Can be formed.

A protective film 125 made of an inorganic insulating material such as a silicon nitride film or an organic insulating material is formed on the driving transistor T 2 and a contact hole 125 b for exposing the second electrode 124 b is formed on the protective film 125 The anode 126 of the light emitting diode is connected to the second electrode 124b of the driving transistor.

A bank layer 127 and a cathode 129 for exposing a part of the anode 126 are formed on the anode 126 and an organic light emitting layer 128 is formed in the light emitting region between the exposed anode 126 and the cathode 129 And emits light.

Although FIG. 1 illustrates a top emission type in which light is emitted to the front side in one embodiment, a rear or both-side emission type may be applied as needed.

In the case of the front emission type, the anode 126 may include a reflective metal film and a transparent conductive film, or an adhesive layer, a reflective metal film, and a transparent conductive film, and the cathode 129 may be a transparent electrode including a thin metal film. At this time, a transparent conductive film or a metal film may be used as the adhesive layer, and silver or aluminum having high reflectivity may be used as the reflective metal film. Alternatively, a cathode, which is a reflective electrode, may be formed at the bottom, and an anode that is a transparent electrode may be formed at an upper portion. In this case, the anode may be an inverted-OLED.

Referring to FIG. 2, an operation of the organic light emitting display according to an embodiment of the present invention will be described. Referring to FIG. 2, The switching transistor T1 in the sub-pixel is turned on and a data signal is applied through the data line Dm of the corresponding sub-pixel.

The applied data signal is stored in the capacitor Cst and the driving transistor T2 generates a driving current corresponding to the difference between the data signal stored in the capacitor Cst and the power source voltage VDD, . Since a positive bias is applied to each sub-pixel, the organic light emitting diode OLED emits light corresponding to the driving current, and thus the organic electroluminescent panel displays an image corresponding to the data signal.

Meanwhile, when the second scan signal is applied to the second scan line S11 simultaneously with the application of the first scan signal, the sensing transistor T3, which is a touch sensor, is turned on and the current of the driving transistor T2 is sensed. To the readout line.

5, when a user touches a certain point on the organic electroluminescent panel, the light emitted from the corresponding point to the front surface is reflected and scattered to the rear surface of the driving transistor T2. At this time, the amount of the driving current generated in the driving transistor T2 by the irradiation of light increases, and the amount of the driving current temporarily changes.

This phenomenon is detected through the sensing transistor T3 during a period in which the second scan signal is applied.

That is, at the point where the touch is made, the light is scattered and transmitted to the driving transistor T2 side, which causes the amount of the driving current generated in the driving transistor T2 to increase temporarily.

Referring to FIG. 6, there is shown a graph showing the current flowing through the channel layer of the driving transistor T2 when illumination is irradiated and when the light is not irradiated (Dark), respectively.

It can be seen that the amount of off current is abruptly changed when light is applied to the driving transistor T2 under the condition that Vgs of the driving transistor T2 is in an off state.

The amount of current of the driving transistor T2 changed by light is transmitted to the readout line through the sensing transistor T3.

The signal transmitted through the readout line is transmitted to the digital board through the lead-out unit, and the digital board processes the signal and transmits it to the system. Then, the system performs an operation corresponding to the applied signal.

7 is a block diagram illustrating a signal processing process for sensing a touch position in a touch screen system including an organic electroluminescent panel according to an exemplary embodiment of the present invention.

Referring to FIG. 7, the output current generated from the touch sensor 150 having the sensing transistor T3 in each sub-pixel is transmitted to the lead-out unit 230 through a readout line.

Here, the output current refers to the current of the driving thin film transistor which is changed by reflection of light emitted from the organic light emitting diode as described above.

The lead-out unit 230 converts the output current into a voltage and transmits it to the analog-to-digital converter 310 located on the digital board 300. The analog-to-digital converter 310 converts the signal received through the lead-out unit 230 into a digital signal and transmits the digital signal to the image signal processor 330.

The image signal processor 330 recognizes the signal received through the A / D converter 310 as an image, detects an area having a signal having a threshold value or more, and determines the area as a touched part.

That is, reflection of light may be caused by an object that can reflect light in addition to the finger of a user, so that regions with a strength of a signal exceeding a threshold value are searched to determine a touched portion.

The touch screen system through the above process can convert the magnitude and the signal shape of the current by the lead-out unit 230 and the digital board 300, and can grasp the touch point and the strength of the touch by the user.

Accordingly, the touch screen system including the organic electroluminescent panel according to the embodiment of the present invention is capable of sensing multi-touch because the touch sensor is built in each sub-pixel.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, You will understand.

Therefore, it should be understood that the above-described embodiments are provided so that those skilled in the art can fully understand the scope of the present invention. Therefore, it should be understood that the embodiments are to be considered in all respects as illustrative and not restrictive, The invention is only defined by the scope of the claims.

1 is a block diagram illustrating a touch screen system including an organic electroluminescent panel according to an embodiment of the present invention.

2 is an equivalent circuit diagram illustrating an organic electroluminescent panel according to an embodiment of the present invention.

3 is a timing chart for explaining the operation of the organic electroluminescent panel according to the embodiment of the present invention.

4 is a circuit diagram showing a lead-out unit of a touch screen system according to an embodiment of the present invention.

5 is a schematic cross-sectional view illustrating an operation of the organic electroluminescent panel according to an embodiment of the present invention when a screen is touched.

FIG. 6 is a graph illustrating current characteristics of a driving transistor of an organic electroluminescent panel according to an exemplary embodiment of the present invention when light is irradiated or not. FIG.

FIG. 7 is a block diagram illustrating a signal processing process for detecting a touch position in a touch screen system including an organic electroluminescent panel according to an exemplary embodiment of the present invention. Referring to FIG.

DESCRIPTION OF THE REFERENCE NUMERALS (S)

100: organic electroluminescence panel 200: organic electroluminescence module

210: scan driver 220:

230: a rod out part 300: a digital board

400: system 110: substrate

121: gate electrode 122: gate insulating film

123: semiconductor layer 124a, 124b: first electrode, second electrode

125: protective film 126: anode

127: bank layer 128: organic light emitting layer

129: cathode 130: cover substrate

150: touch sensor

Claims (8)

In an organic electroluminescent panel including a plurality of sub-pixels, The sub- First and second scan lines and data lines; A switching transistor that is turned on by a first scan signal applied from the first scan line and transmits a data signal applied from the data line; A capacitor for receiving a data signal from the switching transistor and storing the data signal; A driving transistor which is turned on by the data signal and generates a driving current corresponding to the data signal; An organic light emitting diode emitting light by the driving current; And And a sensing transistor connected between the organic light emitting diode and the driving transistor and being turned on by a second scan signal applied from the second scan line to sense a change amount of the driving current, Wherein the driving transistor is configured such that light reflected from a touch point on the organic electroluminescent panel is incident on the driving transistor channel region to increase the amount of driving current generated by the driving transistor, Wherein the sensing transistor senses an increased amount of the driving current to determine a touch point position. The method according to claim 1, Wherein the second scan signal is applied after the first scan signal is applied. 3. The method according to claim 1 or 2, The sensing transistor includes: A gate electrode connected to the second scan line; A first electrode connected between the organic light emitting diode and the driving transistor; And And a second electrode for outputting a driving current generated in the driving transistor. An organic electroluminescent panel including a plurality of subpixels; A readout IC electrically connected to the organic electroluminescence panel and measuring a change amount of a driving current flowing in the organic electroluminescence panel; A converter for converting a signal output from the lead-out unit into an electrical signal; And And a video signal processor receiving a signal from the transducer and recognizing an external touch position, The sub- A switching transistor for turning on the first and second scan lines and the data line, a first scan signal applied from the first scan line and transmitting a data signal applied from the data line, a capacitor for storing the data signal, A driving transistor which is turned on by a data signal and generates a driving current corresponding to a difference between the data signal and a power source voltage, an organic light emitting diode which emits light by the driving current, And a sensing transistor which is turned on by a second scan signal applied from the second scan line and senses an amount of the driving current, wherein the driving transistor controls the light reflected from the touch point on the organic electroluminescence panel, And a driving transistor The amount of drive current generated by the gyres is increased, Wherein the sensing transistor senses an increased amount of the driving current to determine a touch point location. 5. The method of claim 4, Wherein the second scan signal is applied after the first scan signal is applied. The method according to claim 4 or 5, The sensing transistor includes: A gate electrode connected to the second scan line; A first electrode connected between the organic light emitting diode and the driving transistor; And And a second electrode for outputting a driving current generated in the driving transistor, And a second electrode of the sensing transistor is connected to the lead-out portion. The method according to claim 6, The lead- An amplifier for amplifying a signal output from the sensing transistor, and first and second capacitors. 8. The method of claim 7, The amplifier is an operational amplifier, (-) input terminal of the operational amplifier is connected to a first capacitor connected to the sensing transistor, a (+) input terminal of the operational amplifier is connected to a reference voltage, and an output terminal of the operational amplifier is connected to a negative (-) input terminal of the operational amplifier. And a second capacitor connected to the input terminal.

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