# Patent

## Title
Organic light emitting device having touch sensor disposed thereon

## Abstract

Embodiments of the present invention generally relate to a touch sensible organic light emitting device. The organic light emitting device according to an exemplary embodiment of the present invention comprises: a substrate; a thin film transistor disposed on the substrate; an organic light emitting element connected to the thin film transistor and receiving a data voltage; a plurality of encapsulation thin films disposed on the organic light emitting element, and encapsulating the thin film transistor and the organic light emitting element; a planarization layer disposed on the encapsulation thin film; and a touch sensor disposed on the planarization layer.

## Background
CROSS-REFERENCE TO RELATED APPLICATION
This application claims priority to and the benefit of Korean Patent Application No. 10-2008-0120015 filed in the Korean Intellectual Property Office on Nov. 28, 2008, the entire contents of which are incorporated herein by reference.
BACKGROUND
(a) Technical Field
Embodiments of the present invention generally relate to a touch sensible organic light emitting device.
(b) Description of the Related Art
An organic light emitting device includes two electrodes and an organic light emitting layer interposed between the two electrodes. One of the two electrodes injects holes and the other injects electrons into the light emitting layer. The injected electrons and holes combine to form excitons and the excitons emit light as discharging energy.
An organic light emitting device includes an organic light emitting element and a plurality of thin film transistors for driving it. The thin film transistors comprise a plurality of thin films and are generally disposed at the lower side of the organic light emitting device, the organic light emitting element is disposed at the upper side thereof, and an anode of the organic light emitting element is disposed at the lower side and a cathode thereof is disposed at the upper side.
An organic light emitting element includes an anode and a cathode as two electrodes, and an organic light emitting member as the emission layer disposed therebetween. An organic light emitting member emits light of three primary colors such as red, green, and blue, or white. Materials for the organic light emitting member vary according to the colors that the organic light emitting member emits. When an organic light emitting member emits white light, light emitting materials that emit red, green, and blue are stacked so that the synthesized light becomes white. Moreover, in the case where the organic light emitting member emits the white light, color filters may be added to obtain light of a desired color.
Meanwhile, thin film transistors include a switching transistor for switching a voltage applied to each pixel, and a driving transistor for driving the organic light emitting element.
An organic light emitting device may be classified into a top emission type that emits light in the upper direction and a bottom emission type that emits light in the lower direction.
On the other hand, a touch screen panel is a device for allowing a machine such as a computer to perform a desired command by writing a character, drawing a picture, or executing an icon through touching a finger or a touch pen (or a stylus) on a screen. A display device to which a touch screen panel is attached can determine whether a user finger or a touch pen, etc., touches a screen and touch position information. The cost of such a display device, however, increases due to the touch screen panel. Because of additional processes for adhering or coupling the touch screen panel to the display panel, the yield of the organic light emitting device is reduced, the luminance and the viewing angle of the display panel are deteriorated, and the overall thickness of the product increases.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the disclosure and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.
SUMMARY
An organic light emitting device according to an exemplary embodiment of the present invention comprises: a substrate; a thin film transistor disposed on the substrate; an organic light emitting element connected to the thin film transistor and receiving a data voltage; a plurality of encapsulation thin films disposed on the organic light emitting element, and encapsulating the thin film transistor and the organic light emitting element; a planarization layer disposed on the encapsulation thin film; and a touch sensor disposed on the planarization layer.
The plurality of encapsulation thin films may comprise an organic insulator or an inorganic insulator.
The inorganic insulator may comprise silicon oxide or silicon nitride.
The planarization layer may comprise an organic material, and has a flat surface.
The touch sensor may comprise a variable capacitor connected to a sensing signal line transmitting a sensing signal, and a reference capacitor connected between the sensing signal line and a reference voltage terminal.
A capacitance of the variable capacitor may be changed according to an external touch comprising a pressure applied to one terminal of the variable capacitor.
The touch sensor may comprise a first transparent conductive layer.
The first transparent conductive layer may comprise indium tin oxide (ITO) or indium zinc oxide (IZO).
A plurality of electrode island portions each disposed on a corner of the substrate and transmitting a voltage to the first transparent conductive layer may be further comprised.
A signal line pattern connecting the plurality of electrode island portions; and a sensing signal processor connected to the signal line pattern and receiving the changed voltage according to a touch on the first transparent conductive layer and generating a digital sensing signal may be further comprised.
A plurality of electrode island portions each disposed on a corner of the substrate and transmitting a high-frequency signal to the first transparent conductive layer, a signal line pattern connecting the plurality of electrode island portions, and a sensing signal processor connected to the signal line pattern and receiving a changed high-frequency signal according to a touch on the first transparent conductive layer and generating a sensing signal may be further comprised.
The touch sensor may further comprise a first insulating layer disposed on the first transparent conductive layer; and a second transparent conductive layer disposed on the first insulating layer.
A plurality of electrode island portions each disposed on a corner of the substrate and transmitting a voltage to the first and second transparent conductive layers, a signal line pattern connecting the plurality of electrode island portions, and a sensing signal processor connected to the signal line pattern and receiving a changed voltage according to a touch on the second transparent conductive layer and generating a sensing signal may be further comprised.
A plurality of electrode island portions each disposed on a corner of the substrate and transmitting a high-frequency signal to the first and second transparent conductive layers, a signal line pattern connecting the plurality of electrode island portions, and a sensing signal processor connected to the signal line pattern and receiving a changed high-frequency signal according to a touch on the second transparent conductive layer and generating a sensing signal may be further comprised.
A second insulating layer disposed on the second transparent conductive layer may be further comprised.
The first transparent conductive layer may be connected to the reference voltage terminal, and the second transparent conductive layer is connected to a sensing signal line disposed on the substrate.
A sensing signal processor receiving a changed voltage of the second transparent conductive layer according to a touch on the second insulating layer and generating a sensing signal may be further comprised.
The organic light emitting element may comprise a pixel electrode connected to the thin film transistor and receiving a data voltage through the thin film transistor, an organic light emitting member disposed on the pixel electrode, and a common electrode disposed on the organic light emitting member.
The thin film transistor may comprise a switching transistor controlled by a scanning signal; and a driving transistor connected to the switching transistor and transmitting an output current to the organic light emitting element.



BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of a touch sensible organic light emitting device according to an exemplary embodiment of the present invention.
FIG. 2 is an equivalent circuit diagram of a touch sensible organic light emitting device according to an exemplary embodiment of the present invention.
FIG. 3 is a cross-sectional view of one pixel of a touch sensible organic light emitting device according to an exemplary embodiment of the present invention.
FIG. 4 is an equivalent circuit diagram of a touch sensor of a touch sensible organic light emitting device according to an exemplary embodiment of the present invention.
FIG. 5 and FIG. 6 are cross-sectional views of one pixel of a touch sensible organic light emitting device according to an exemplary embodiment of the present invention.
FIG. 7 is a view showing a connection relationship of a high-frequency sensor in a touch sensible organic light emitting device according to an exemplary embodiment of the present invention.



DETAILED DESCRIPTION
Embodiments of the present invention will be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present disclosure.
In the drawings, the thickness of layers, films, panels, regions, etc., are exaggerated for clarity. Like reference numerals designate like elements throughout the specification. It will be understood that when an element such as a layer, film, region, or substrate is referred to as being “on” another element, it may be directly on the other element, or intervening elements may also be present. In contrast, when an element is referred to as being “directly on” another element, there are no intervening elements present.
A touch sensible organic light emitting device according to an exemplary embodiment of the present invention will now be described with reference to FIGS. 1 and 2.
FIG. 1 is a block diagram of a touch sensible organic light emitting device according to an exemplary embodiment of the present invention, and FIG. 2 is an equivalent circuit diagram of a touch sensible organic light emitting device according to an exemplary embodiment of the present invention.
Referring to FIG. 1, an organic light emitting device according to an exemplary embodiment of the present invention includes a display panel 300 including a touch sensor (not shown), a scan driver 400, a data driver 500 and a sensing signal processor 800 that are connected to the display panel 300, and a touch determining unit 900 connected to the sensing signal processor 800.
Referring to FIG. 1 and FIG. 2, an organic light emitting device according to the present exemplary embodiment includes a plurality of signal lines 121, 171, and 172, and a plurality of pixels PX connected thereto and arranged substantially in a matrix.
The signal lines include a plurality of scanning signal lines 121 for transmitting gate signals (or scanning signals), a plurality of data lines 171 for transmitting data signals, and a plurality of driving voltage lines 172 for transmitting a driving voltage. The scanning signal lines 121 extend substantially in a row direction and are substantially parallel to each other, and the data lines 171 extend substantially in a column direction and are substantially parallel to each other. Although the driving voltage lines 172 are shown as extending substantially in a column direction, the driving voltage lines 172 may extend in a row direction or in a column direction, or may be formed in a matrix. Also, the signal lines may further comprise a sensing signal line (not shown) for transmitting a sensing signal of the touch sensor.
As shown in FIG. 2, each pixel PX includes a switching transistor Qs, a driving transistor Qd, a storage capacitor Cst, and an organic light emitting element LD.
The switching transistor Qs includes a control terminal, an input terminal, and an output terminal, in which the control terminal is connected to the scanning signal line 121, the input terminal is connected to the data line 171, and the output terminal is connected to the driving transistor Qd. The switching transistor Qs transmits a data signal received from the data line 171 to the driving transistor Qd in response to the scanning signal received from the scanning signal line 121.
The driving transistor Qd also includes a control terminal, an input terminal, and an output terminal, in which the control terminal is connected to the switching transistor Qs, the input terminal is connected to the driving voltage line 172, and the output terminal is connected to the organic light emitting element LD. The driving transistor Qd transmits an output current ILD of which the magnitude varies according to the voltage applied between the control terminal and the output terminal of the driving transistor Qd.
The capacitor Cst is connected between the control terminal and the input terminal of the driving transistor Qd. The capacitor Cst stores the data signal applied to the control terminal of the driving transistor Qd and maintains the stored data signal even after the switching transistor Qs is turned off.
The organic light emitting element LD may be an organic light emitting diode (OLED), for example having an anode connected to the output terminal of the driving transistor Qd and a cathode connected to a common voltage Vss. The organic light emitting element LD emits light of which the intensity is varied according to the output current ILD of the driving transistor Qd, to display an image. The organic light emitting element LD may include an organic material uniquely emitting at least one of the primary colors such as red, green, or blue, or a white color, and the organic light emitting device emits desired images by a spatial sum thereof.
The switching transistor Qs and the driving transistor Qd may be n-channel field effect transistors (FET); however, at least one of the switching transistor Qs and the driving transistor Qd may be a p-channel FET. Moreover, the connection relationship among the transistors Qs and Qd, the storage capacitor Cst, and the organic light emitting element LD may be changed.
Referring again to FIG. 1 and FIG. 2, the scan driver 400 is connected to the scanning lines 121, and applies scanning signals that are a combination of a high voltage Von for turning on the switching transistors Qs and a low voltage Voff for turning off the switching transistors Qs to the scanning lines 121.
The data driver 500 is connected to the data lines 171 in the display panel 300 and applies data voltages to the data lines 171.
The sensing signal processor 800 receives a sensing signal from the touch sensor (not shown) of the display panel 300, performs a signal process such as amplifying and filtering, and converts the processed signal to a digital sensing signal DS through an analog-digital conversion.
The touch determining unit 900 receives the digital sensing signal DS from the sensing signal processor 800, performs a predetermined calculation process, and determines whether the display panel 300 is touched or not as well as a touch position to generate a touch information INF, and then, outputs the touch information INF to an external device. An external device may transmit the image signal based on the touch information INF to the organic light emitting device. Alternatively, when the external device directly receives the digital sensing signal DS and performs the function of the touch determining unit 900 such as determining the touch position, the touch determining unit 900 may be omitted.
Next, a display operation of the organic light emitting device will be described according to one or more embodiments.
The data driver 500 receives digital output image signals for a row of pixels PX, and converts the digital output image signals into analog data voltages to apply to the data lines 171.
The scan driver 400 applies the high voltage Von to the gate lines 121 to turn on the switching element Qs coupled to the gate lines 121. Thereby, the data voltage applied to the data lines 171 is applied to the corresponding pixel PX through the turned on switching element Qs.
The driving transistor Qd receives the data voltages through the turned on switching element Qs thereby generating a corresponding output current ILD. The organic light emitting element LD emits light having an intensity corresponding to the output current ILD of the driving transistor Qd.
By repeating the above procedure by a unit of one horizontal period, which is denoted by “1H”, the scanning signal is sequentially applied for all scanning signal lines 121 and the data voltage is applied to all pixels PX to display an image of one frame.
Next, the display panel of the organic light emitting device shown in FIG. 1 and FIG. 2 will be described in detail according to one or more embodiments with reference to FIG. 3 and FIG. 4 as well as FIG. 1 and FIG. 2.
FIG. 3 is a cross-sectional view of one pixel of a touch sensible organic light emitting device according to an exemplary embodiment of the present invention, and FIG. 4 is an equivalent circuit diagram of a touch sensor of a touch sensible organic light emitting device according to an exemplary embodiment of the present invention,
Referring to FIG. 4, a touch sensor of a touch sensible organic light emitting device according to an exemplary embodiment of the present invention includes a variable capacitor Cv connected to the sensing signal line SL, and a reference capacitor Cr connected between the sensing signal line SL and the reference voltage Vr terminal.
The capacitance of the variable capacitor Cv may be varied according to an external touch applied to the upper terminal of the variable capacitor Cv such as a contact (touch) of a finger Fn of a user. For example, the external touch may be a pressure. If the capacitance of the variable capacitor Cv is changed, the node voltage Vn between of the reference capacitor Cr and the variable capacitor Cv depending on the capacitance changes. The node voltage Vn is transmitted through the sensing signal line SL as a sensing signal, and either the existence or lack of a touch as well as a touch position may be determined based on the sensing signal. Here, the reference capacitor Cr has a fixed capacitance and the reference voltage Vr applied to the reference capacitor Cr has a uniform voltage, such that the node voltage Vn is changed within a predetermined range. Accordingly, the sensing signal may always have a voltage level within a predetermined range such that the existence or lack of a touch as well as touch position may be easily determined.
Next, a cross-sectional structure of the driving transistor Qd, the organic light emitting element LD, and the touch sensor of a touch sensible organic light emitting device according to an exemplary embodiment of the present invention will be described with reference to FIG. 3, FIG. 1, FIG. 2, and FIG. 4.
A plurality of gate conductors including control electrodes 124 are formed on an insulation substrate 110 made of transparent glass or plastic.
A gate insulating layer 140 that may be made of silicon nitride (SiNx) or silicon oxide (SiOx) is formed on the gate conductor.
A plurality of semiconductors 154 are formed on the gate insulating layer 140. The semiconductors 154 overlap the control electrodes 124.
A plurality of pairs of ohmic contacts 163 and 165 are formed on the semiconductors 154.
A plurality of data conductors including a plurality of driving voltage lines 172 and a plurality of output electrodes 175 are formed on the ohmic contacts 163 and the gate insulating layer 140.
The driving voltage lines 172 transmit a driving voltage, and include input electrodes 173 extending toward the control electrodes 124.
The output electrodes 175 are separated form the driving voltage lines 172.
The input electrodes 173 and the output electrodes 175 oppose each other on the semiconductors 154.
A control electrode 124, an input electrode 173, and an output electrode 175 form a driving transistor Qd along with a semiconductor 154, and a channel of the driving transistor Qd is formed in the semiconductor 154 between the input electrode 173 and the output electrode 175.
The ohmic contacts 163 and 165 are only disposed between the underlying semiconductor 154 and the overlying data conductor, thereby reducing the contact resistance therebetween. The semiconductor 154 has a portion that is exposed without being covered with the input electrode 173 and the output electrode 175, and a portion between the source electrodes 173 and the drain electrodes.
A lower passivation layer 180p made of an inorganic insulator such as silicon nitride or silicon oxide is formed on the gate insulating layer 140, the data conductor, and the exposed semiconductor 154.
An upper passivation layer 180q is formed on the lower passivation layer 180p. The upper passivation layer 180q may be made of an organic material, and may have a flat surface.
The lower passivation layer 180p and the upper passivation layer 180q have contact holes 185 exposing the output electrodes 175.
A plurality of pixel electrodes 191 are formed on the upper passivation layer 180q. The pixel electrodes 191 may be made of a reflective metal such as Al, Ag, Au, Pt, Ni, Cu, W, or alloys thereof. The pixel electrodes 191 may further include a transparent electrode that is disposed on or under the reflective metal and made of a conductive metal oxide such as indium tin oxide (ITO) or indium zinc oxide (IZO). The transparent electrode may improve the cohesion between the layer made of a reflective metal and another layer, and may prevent corrosion thereof.
The pixel electrodes 191 are physically-electrically connected to the output electrodes 175 through the contact holes 185.
Partitions 360 are formed on the upper passivation layer 180. The partitions 360 define a plurality of openings enclosing edges of the pixel electrodes 191 like a bank, and may be made of an organic insulator or an inorganic insulator. Alternatively, the partitions 360 may be made of a photoresist including black pigments, and in this case, the partitions 360 may function as a light blocking member, thereby simplifying the manufacturing process.
An organic light emitting member 370 is formed in openings defined by the partitions 360 on the pixel electrodes 191. The organic light emitting member 370 may be made of an organic material uniquely emitting light of one primary color such as red, green, or blue. The organic light emitting device displays a desired image by spatially combining primary colors of the organic light emitting members 370.
The organic light emitting member 370 may have a multi-layer structure including auxiliary layers for improving light emitting efficiency of an emission layer (not shown) in addition to the emission layer. An auxiliary layer may include an electron transport layer (not shown) and a hole transport layer (not shown) that achieve a balance of electrons and holes, and an electron injection layer (not shown) and a hole injection layer (not shown) that reinforce the injection of the electrons and the holes.
A common electrode 270 is formed on the organic light emitting member 370. The common electrode 270 receives a common voltage Vss, and may be made of a transparent conductive material such as ITO or IZO, etc., or of a thin metal layer through which light may be transmitted.
In the organic light emitting device, a pixel electrode 191, an organic light emitting member 370, and the common electrode 270 form an organic light emitting element LD having the pixel electrode 191 as an anode and the common electrode 270 as a cathode, or vice versa. The organic light emitting device display emits light in the upper direction with respect to the substrate 110 to display images.
An encapsulation thin film layer 260 including a first encapsulation thin film 261, a second encapsulation thin film 262, and a third encapsulation thin film 263 is formed on the common electrode 270. The first, second, and third encapsulation thin films 261, 262, and 263 may be made of an inorganic material such as silicon oxide or silicon nitride, or of an organic insulator. The encapsulation layer encapsulates the organic light emitting member 370 and the common electrode 270 such that moisture and/or oxygen from the exterior may be prevented from flowing into them and oxidation of the organic light emitting member 370 and the common electrode 270 may be prevented. The third encapsulation thin film 263 that is disposed uppermost may completely encapsulate the organic light emitting member 370 and the common electrode 270 by covering the upper surface of the substrate 110 at the edges of the display panel 300. Accordingly, the thin films are used to encapsulate and protect the organic light emitting member 370 and so forth such that the thickness of the organic light emitting device may be further reduced and the display characteristics such as transmittance and viewing angle may be improved.
According to another exemplary embodiment of the present invention, the encapsulation thin film layer 260 may be made of a single layer, double layers, or a plurality of layers of more than two layers including inorganic insulators or organic insulators.
A planarization layer 240 is formed on the encapsulation thin film layer 260. The planarization layer 240 may be made of an organic material, and flatten the surface on the encapsulation thin film layer 260.
A lower transparent conductive layer 232, an insulating layer 220, and an upper transparent conductive layer 231 may be sequentially formed on the whole surface of the planarization layer 240.
The lower and upper transparent conductive layers 232 and 231 may be made of a transparent conductive material such as ITO, ATO (antimony tin oxide), or IZO. The lower transparent conductive layer 232 may receive a predetermined voltage such as the reference voltage Vr, and the upper transparent conductive layer 231 may be connected to the sensing signal line SL.
The insulating layer 220 may be made of an inorganic material such as silicon oxide or silicon nitride, or of an organic insulator through, for example, spin coating or printing.
The lower transparent conductive layer 232 and the upper transparent conductive layer 231 form a reference capacitor Cr along with the insulating layer 220.
A surface insulating layer 210 that may be made of an inorganic material such as silicon oxide or silicon nitride, or an organic insulator, is coated on the whole surface of the upper transparent conductive layer 231. The upper surface of the surface insulating layer 210 or an external touch object form the variable capacitor Cv along with the upper transparent conductive layer 231, wherein the surface insulating layer 210 between the upper surface of the surface insulating layer 210 or the external touch object, and the upper transparent conductive layer 231 functions as a dielectric material of the variable capacitor Cv.
Referring to FIG. 3 and FIG. 4, when an external touch by a finger Fn is applied to any portion on the surface insulating layer 210, the voltage of the upper transparent conductive layer 231, that is, the node voltage Vn between the reference capacitor Cr and the variable capacitor Cv is changed. Alternatively, the capacitance of the variable capacitor Cv changes at the touch portion such that the node voltage Vn of the upper transparent conductive layer 231 may be changed. For example, if a pressure by a touch is applied to the surface insulating layer 210, the thickness of the surface insulating layer 210 is changed so that the capacitance of the variable capacitor Cv may be changed. Thus, the node voltage Vn of the upper transparent conductive layer 231 depending on the capacitance of the variable capacitor Cv is changed. The changed node voltage Vn of the upper transparent conductive layer 231 is transmitted through the sensing signal line SL as a sensing signal, and either a touch or a lack of touch may be determined based on the sensing signal. Such sensing operation is separately executed from the above-described display operation, and may not be influenced by the display operation or vice versa.
According to another embodiment, a conductive layer (not shown) may be further formed on the surface insulating layer 210. Also, a coating layer (not shown) for protection of the upper transparent conductive layer 231 and reduction of noises may be further formed on the surface insulating layer 210.
Next, a touch sensible organic light emitting device according to another exemplary embodiment of the present invention will be described with reference to FIG. 5 to FIG. 7 as well as FIG. 1 and FIG. 2.
FIG. 5 and FIG. 6 are cross-sectional views of one pixel of a touch sensible organic light emitting device according to an exemplary embodiment of the present invention, and FIG. 7 is a view showing a connection relationship of a high-frequency sensor in a touch sensible organic light emitting device according to an exemplary embodiment of the present invention.
Referring to FIG. 5 and FIG. 6, a touch sensible organic light emitting device according to an exemplary embodiment of the present invention has almost the same cross-sectional structure as the organic light emitting device shown in the embodiment of FIG. 3. In the present exemplary embodiment, descriptions of the same elements will be omitted, and the same constituent elements as in the above-described exemplary embodiment are indicated by the same reference numerals.
Referring to FIG. 5, a gate conductor including a control electrode 124, a gate insulating layer 140, a plurality of semiconductors 154, a plurality of pairs of ohmic contacts 163 and 165, a plurality of data conductors including a driving voltage line 172 and an output electrode 175, a lower passivation layer 180p and an upper passivation layer 180q, a plurality of pixel electrodes 191, a partition 360, an organic light emitting member 370, a common electrode 270, an encapsulation thin film layer 260 including a first encapsulation thin film 261, a second encapsulation thin film 262, and a third encapsulation thin film 263, a planarization layer 240, and a transparent conductive layer 232a are sequentially formed on the insulation substrate 110.
Referring to FIG. 1 and FIG. 7, a plurality of electrode island portions 233 are formed at the four corners of the display panel 300 in the organic light emitting device according to the present exemplary embodiment. The electrode island portions 233 are connected to the four corners of the transparent conductive layer 232a. The electrode may include electrode islands (not shown) for transmitting a high-frequency signal or a predetermined voltage to the transparent conductive layer 232a and a signal receiver (not shown) for sensing a changed high-frequency signal or voltage.
A signal line pattern 80 that may have a stripe shape and that may be made of a metal such as silver or aluminum is formed near the edge of the display panel 300. The signal line pattern 80 connects four electrode island portions 233, and the end portion thereof is connected to the sensing signal processor 800. The signal line pattern 80 may be formed on the transparent conductive layer 232a. 
In such an organic light emitting device, a high-frequency signal or a voltage is applied to the transparent conductive layer 232a through the electrode islands (not shown) of the electrode island portions 233. If an external object such as a finger Fn touches the transparent conductive layer 232a, the high-frequency signal is changed or the voltage is changed, and the changed signal such as the changed high-frequency signal is detected by the signal receiver (not shown) of the electrode island portions 233. The detected signal is input to the sensing signal processor 800 and the touch determining unit 900 through the signal line pattern 80, thereby determining the touch position.
Also, referring to FIG. 6, in a touch sensible organic light emitting device according to another exemplary embodiment of the present invention, a lower transparent conductive layer 232 may be formed in replacement of the transparent conductive layer 232a of the organic light emitting device shown in the embodiment of FIG. 5. Also, an insulating layer 220, an upper transparent conductive layer 231 and a coating layer 215 may be further formed on the lower transparent conductive layer 232. The coating layer 215 may protect the upper transparent conductive layer 231 from contamination and external influence.
Referring to FIG. 6 and FIG. 7, the lower transparent conductive layer 232 and the upper transparent conductive layer 231 are connected to the electrode islands (not shown) of the electrode island portions 233, thereby receiving the high-frequency signal or the predetermined voltage. A changed high-frequency signal or a changed voltage by a touch is detected by the signal receiver (not shown) of the electrode island portions 233. Also, many characteristics of the organic light emitting device shown in the embodiments of FIG. 5 and FIG. 7 may be applied to the organic light emitting display device shown in the embodiments of FIG. 6 and FIG. 7.
Numerous characteristics of the touch sensible organic light emitting device shown in the embodiment of FIG. 3 may be applied identically to the organic light emitting device shown in the embodiments of FIG. 5 to FIG. 6.
The sensing method of an organic light emitting device according to an exemplary embodiment of the present invention is an example of a touch sensing method. A touch sensor operating by various sensing methods such as the capacitance type sensing method may be included.
According to an exemplary embodiment of the present invention, organic light emitting elements and thin film transistors of an organic light emitting device may be encapsulated by several encapsulation thin films, and a touch sensor of the capacitance type sensing method that is thin may be formed. Accordingly, the thickness of the touch sensible organic light emitting device may be reduced, and the display characteristics such as transmittance and viewing angles may be improved.
Embodiments of the present invention may be applied to an organic light emitting device having various structures.
While this disclosure has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the disclosure is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

## Claims

1. An organic light emitting device comprising:
a substrate;
a thin film transistor disposed on a first surface of the substrate;
an organic light emitting element connected to the thin film transistor and configured to receive a data voltage;
a plurality of encapsulation thin films disposed on the organic light emitting element and encapsulating the organic light emitting element, wherein the plurality of encapsulation thin films include
a first portion overlapping the organic light emitting element in a direction perpendicular to the first surface of the substrate and a second portion connected to the first portion and including the same encapsulation thin films as the first portion, wherein a maximum distance between an upper surface of the first portion and the first surface of the substrate is less than a maximum distance between an upper surface of the second portion and the first surface of the substrate;
a planarization layer disposed on the plurality of encapsulation thin films, wherein a maximum thickness of the planarization layer corresponding to the first portion is greater than a maximum thickness of the planarization layer corresponding to the second portion; and
a touch conductive layer disposed on a planar surface of the planarization layer.

2. The organic light emitting device of claim 1, wherein the plurality of encapsulation thin films comprises an organic insulator or an inorganic insulator.

3. The organic light emitting device of claim 2, wherein the inorganic insulator comprises silicon oxide or silicon nitride.

4. The organic light emitting device of claim 1, wherein the planarization layer comprises an organic material and has a flat surface.

5. The organic light emitting device of claim 1, wherein the touch sensor comprises:
a variable capacitor connected to a sensing signal line, the sensing signal line configured to transmit a sensing signal; and
a reference capacitor connected between the sensing signal line and a reference voltage terminal.

6. The organic light emitting device of claim 5, wherein a capacitance of the variable capacitor is changed according to an external touch input comprising a pressure applied to one terminal of the variable capacitor.

7. The organic light emitting device of claim 1, wherein the conductive layer comprises a first transparent conductive layer.

8. The organic light emitting device of claim 7, wherein the first transparent conductive layer comprises indium tin oxide (ITO) or indium zinc oxide (IZO).

9. The organic light emitting device of claim 7, further comprising
a plurality of electrode island portions each disposed on a corner of the substrate, the plurality of electrode island portions transmitting a voltage to the first transparent conductive layer.

10. The organic light emitting device of claim 9, further comprising:
a signal line pattern connecting the plurality of electrode island portions; and
a sensing signal processor connected to the signal line pattern, the sensing signal processor receiving a changed voltage according to a touch on the first transparent conductive layer and generating a digital sensing signal.

11. The organic light emitting device of claim 7, further comprising:
a plurality of electrode island portions each disposed on the corner of the substrate and transmitting a high-frequency signal to the first transparent conductive layer;
a signal line pattern connecting the plurality of electrode island portions; and
a sensing signal processor connected to the signal line pattern, the sensing signal processor receiving a changed high-frequency signal according to a touch on the first transparent conductive layer and generating a sensing signal.

12. The organic light emitting device of claim 7, wherein the touch sensor further comprises:
a first insulating layer disposed on the first transparent conductive layer; and
a second transparent conductive layer disposed on the first insulating layer.

13. The organic light emitting device of claim 12, further comprising:
a plurality of electrode island portions each disposed on a corner of the substrate and transmitting a voltage to the first and second transparent conductive layers;
a signal line pattern connecting the plurality of electrode island portions; and
a sensing signal processor connected to the signal line pattern, the sensing signal processor receiving a changed voltage according to a touch on the second transparent conductive layer and generating a sensing signal.

14. The organic light emitting device of claim 12, further comprising:
a plurality of electrode island portions each disposed on a corner of the substrate and transmitting a high-frequency signal to the first and second transparent conductive layers;
a signal line pattern connecting the plurality of electrode island portions; and
a sensing signal processor connected to the signal line pattern, the sensing signal processor receiving a changed high-frequency signal according to a touch on the second transparent conductive layer and generating a sensing signal.

15. The organic light emitting device of claim 12, further comprising:
a second insulating layer disposed on the second transparent conductive layer.

16. The organic light emitting device of claim 15, wherein the first transparent conductive layer is connected to the reference voltage terminal, and the second transparent conductive layer is connected to a sensing signal line disposed on the substrate.

17. The organic light emitting device of claim 16, further comprising:
a sensing signal processor configured to receive a changed voltage of the second transparent conductive layer based on a touch input to the second insulating layer, and to generate a sensing signal based on the changed voltage.

18. The organic light emitting device of claim 1, wherein the organic light emitting element comprises:
a pixel electrode connected to the thin film transistor and configured to receive a the data voltage through the thin film transistor;
an organic light emitting member disposed on the pixel electrode; and
a common electrode disposed on the organic light emitting member.

19. The organic light emitting device of claim 1, wherein the thin film transistor comprises:
a switching transistor controlled by a scanning signal; and
a driving transistor connected to the switching transistor and configured to transmit an output current to the organic light emitting element.