KR20090036333A - Organic light emitting diode - Google Patents

Abstract

An organic light emitting diode is provided to realize a touch screen by controlling a positive voltage and a negative voltage of a part of the panel reversely and sensing an optical current which is generated from the external light. An organic light emitting diode comprises a substrate member(44), a first electrode layer(41), an organic light-emitting layer(43), a second electrode layer(42), a volume control IC(60), a sensor unit(50), and a fixed region. The organic light-emitting layer is formed on the first electrode layer. The energy is radiated through recombination of hole and electronics. A sensor unit senses the amount of an optical current generated in an organic light-emitting layer. The polarity of cathode and anode are adjusted reversely at the fixed region. The first voltage supply unit generates the optical current in the organic light-emitting layer by applying a voltage smaller than the voltage supplied to the second electrode layer. The sensor unit senses the amount of the optical current generated in the organic light-emitting layer. If the optical current is reduced at the fixed region, it is determined that the contact is generated at fixed region.

Description

Organic light emitting display device {ORGANIC LIGHT EMITTING DIODE}

The present invention relates to an organic light emitting display device that implements a touch screen by sensing an external contact by using a change in photocurrent generated in the organic light emitting display device.

The present invention relates to an organic light emitting display device, and more particularly, to an organic light emitting display device for implementing a touch screen on a panel of an organic light emitting display device using photocurrent.

Recently, the movement to the information society is accelerating, and as the necessity to send and receive information anytime and anywhere increases, the information display is shifting from the conventional CRT display to the flat panel display.

Among them, liquid crystal displays (LCDs) are most commonly used as flat panel displays because of their advantages of providing light and clear image quality. However, liquid crystal displays (LCDs) are not light emitting devices but are light emitting devices. Due to technical limitations in terms of viewing angle and large area, efforts are being made to develop new flat panel displays that can overcome these shortcomings. One of these new flat panel displays is an organic light emitting diode (OLED), which can be driven at low voltage, has a wide viewing angle and a fast response speed, and is light-emitting as a self-luminous type. Recently, many countries have spurred the commercialization.

In general, an OLED is a display device for electrically exciting a fluorescent organic compound to emit light, and is structured to display an image by voltage driving or current driving N × M organic light emitting cells arranged in a matrix.

Since the introduction of OLED by Tang and Van Slyke in 1987, indium tin oxide (ITO) has been commonly used as an anode material for OLEDs, having a high conductivity of 4.7 eV. In the case of a general OLED using the anode made of ITO, the light generated from the light emitting layer becomes a bottom-emitting OLED emitting light through the anode, that is, ITO.

However, in the case of an active matrix OLED, since two or more transistors are required to drive one OLED, there is a disadvantage in that the light generated in the OLED emitting layer, that is, the aperture ratio is reduced.

In order to solve this problem, research on transparent OLED using both cathode and anode as transparent conductive oxide, ITO, has been started. After that, as the back electrode, materials with high reflectivity of 90% or more, such as Ag and Al, are used. Research has been conducted to improve this. On the other hand, inverted top-emitting OLEDs using a cathode as the back electrode among TOLEDs are very attractive in that n-channel transistors having excellent electrical characteristics, in particular, charge mobility, can be applied to AMOLEDs.

However, the driving method of the organic light emitting display device is how to drive the circuit when the organic light emitting diode panel enters the sub window or the main window, and thus touches the display device. There is a problem that it is difficult to apply the screen.

Recently, a method of designing a keypad in a front window using a white organic light emitting diode has been examined, but there are limitations in applying it to a sophisticated touch screen.

Accordingly, an object of the present invention is to propose a new structure in which a touch screen is applied to an organic light emitting display panel to solve the above problem.

In order to solve the above problem, the present invention is to adjust the voltage of the anode and the cathode to a part of the organic light emitting display panel in reverse to sense the photocurrent generated by the external light and to determine the external contact by using the organic, The touch screen may be implemented in the light emitting display panel.

According to the present invention, by implementing a touch screen using a change in the photocurrent generated in the organic light emitting display device, it is possible to overcome the difficulty of manufacturing a touch screen in the conventional organic light emitting display device.

In addition, the photocurrent can be used not only as a touch screen but also as a sensor for other purposes.

The present invention relates to an organic light emitting display device, and more particularly, to an organic light emitting display device in which a touch screen is implemented on a panel of an organic light emitting display device using photocurrent.

In an organic light emitting display device according to an embodiment of the present invention, an organic light emitting display device including an anode, a cathode and an organic light emitting layer interposed between the anode and the cathode to emit energy due to the recombination of holes and electrons, And a predetermined region for reversing the polarity of the positive electrode and the negative electrode.

Preferably, the polarity of the positive electrode and the negative electrode is adjusted by adjusting the magnitude of the voltage applied to the positive electrode. Specifically, the magnitude of the voltage applied to the positive electrode is adjusted to be smaller than the voltage applied to the negative electrode. Reverse the polarity.

Preferably, the polarity of the anode and the cathode is reversed to decompose the hole-electron pair in the organic light emitting layer to form a photocurrent.

An organic light emitting display device according to another embodiment of the present invention, a substrate member; A first electrode layer formed on the substrate member; An organic light emitting layer formed on the first electrode layer and emitting energy due to recombination of holes and electrons; A second electrode layer formed on the organic light emitting layer; And a voltage controller configured to apply a voltage to the first electrode layer and the second electrode layer, wherein the voltage controller controls the voltages of the first electrode layer and the second electrode layer to form a photocurrent in the organic light emitting layer. It features.

Preferably, the apparatus further includes a sensor unit configured to detect an amount of photocurrent formed in the organic light emitting layer, wherein the voltage controller is configured to apply a voltage to the first voltage applying unit and the second electrode layer to apply a voltage to the first electrode layer. And a second voltage applying unit.

Preferably, the sensor unit determines that contact has occurred in the predetermined region when the photocurrent in a predetermined region decreases, and when a contact occurs in the sensor unit, a specific menu displayed on the display screen including the adjustment region is displayed. Is executed.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily understand and implement the present invention.

1 is a conceptual diagram of a general organic light emitting display device.

The organic light emitting display device has various hierarchical structures as shown in FIGS. 2A to 2E to be described later. In the present specification, an example in which the organic light emitting layer includes five layers will be described.

As shown in FIG. 1, one cell of the organic light emitting display device includes an anode electrode layer ITO 11, an organic light emitting layer 18, and a cathode electrode layer 12.

The organic light emitting layer 18 has a light emitting layer (EML, 15), an electron transport layer (ETL, 16), and a hole transport layer (HTL) in order to improve the light emission efficiency by improving the balance between electrons and holes. And a multi-layer structure including 14), and additionally include an electron injection layer (EIL) 17 and a hole injection layer (HIL) 13.

The organic light emitting cells are arranged in an N × M matrix to form an organic light emitting display panel. Here, when both the anode electrode 11 and the cathode electrode 12 are used as the transparent electrode, double-sided display is possible.

As shown in FIG. 1, holes are injected from the anode electrode 11, electrons are injected from the cathode electrode 12 into the light emitting layer 15, and the injected electrons and holes are recombined in the light emitting layer 15. The recombination energy raises the energy level from a stable ground state to a high unstable excited state, which emits energy when it returns to its original ground state, where light is generated.

Accordingly, the organic light emitting display device may emit light without a separate backlight like the liquid crystal display (LCD).

2A to 2B are conceptual views illustrating various hierarchical structures of a general organic light emitting display device.

As described above, the organic light emitting layer included in the organic light emitting display device may vary. In FIGS. 2A to 2E, a single layer structure (FIG. 2A), a two layer structure (FIG. 2B), a three layer structure (FIG. 2C), The four layer structure (FIG. 2D) and the five layer structure (FIG. 2E) are shown sequentially.

The organic light emitting display device includes an anode electrode layer 21, a cathode electrode layer 22, and a light emitting layer 25, and includes a hole injection layer 23, a hole transport layer 24, an electron transport layer 26, and an electron injection layer ( 27) optionally. In addition, the power supply device 29 applies a voltage such that the voltage of the anode electrode layer 21 is higher than the voltage of the cathode electrode layer 22.

In general, although a single layer type (high molecular weight material) is simple and easy to manufacture, there is an advantage that the multilayer type (low molecular weight material) is easy to select an appropriate material and to make fine improvements.

3A and 3B are schematic diagrams illustrating a principle of generating a photocurrent in an organic light emitting layer and applying the same to a touch screen using a change in the generated photocurrent according to an embodiment of the present invention.

An organic light emitting display device according to an embodiment of the present invention is characterized in that the photocurrent is formed in the light emitting layer 35 and sensed and applied to the touch screen. Accordingly, as shown in FIG. 3, when the voltage of the power supply device 39 is adjusted in contrast to a general display device, the light emitting layer 35 does not exhibit light emission due to recombination of electrons and holes.

That is, when the voltage of the anode electrode layer 31 is smaller than the voltage of the cathode electrode layer 32, electrons and holes are not injected into the light emitting layer 35, so that light emission does not occur as in an organic light emitting display device. .

As shown in FIG. 3A, when the voltage applied to the anode electrode layer 31 and the cathode electrode layer 32 is adjusted by using the power supply device 39, light emission does not occur as in a general organic light emitting display device. Instead, the generation of the hole-electron pair present in the light emitting layer 35 absorbs the light energy incident from the outside to be decomposed into electrons and holes.

Thus, by absorbing external light energy, it is decomposed into electrons and holes, and a photocurrent is formed by the generated electrons. Since the amount of light incident from the outside is constant, if there is no external interference in the organic light emitting display, the photocurrent has a constant value.

However, in the organic light emitting diode display including a predetermined region for controlling the polarity of the anode and the cathode in reverse according to an embodiment of the present invention, when a contact from the outside occurs on the screen of the display device is incident to the area where the contact occurs Since light is instantaneously reduced, the resulting photocurrent is also instantaneously reduced.

Accordingly, the organic light emitting display device according to an embodiment of the present invention detects whether the amount of photocurrent generated in the light emitting layer 35 is reduced as described above, and executes a specific menu displayed on the display screen including the corresponding contact area. A touch screen can be implemented.

3B is a graph showing the amount of photocurrent generated in the light emitting layer 35 of the organic light emitting diode display over time according to an exemplary embodiment of the present invention.

As shown in FIG. 3B, an instant (dotted line area) occurs when the photocurrent generated in the light emitting layer 35 has a constant value and then decreases. This indicates that an operation of blocking light incident into the organic light emitting display panel, that is, contact with the screen has occurred.

4 is a block diagram of an organic light emitting display device according to an embodiment of the present invention.

An organic light emitting display device according to an embodiment of the present invention, the substrate member 44; A first electrode layer 41 formed on the substrate member 44; An organic emission layer 43 formed on the first electrode layer 41 and emitting energy due to recombination of holes and electrons; A second electrode layer 42 formed on the organic light emitting layer; And a voltage controller 60 for applying a voltage to the first electrode layer 41 and the second electrode layer 42.

In addition, the sensor unit 50 for detecting the amount of photocurrent generated in the organic light emitting layer 43.

In addition, the voltage controller 60 may include a first voltage applying unit 61 for applying a voltage to the first electrode layer 41 and a second voltage applying unit 62 for applying a voltage to the second electrode layer 42. It includes.

Accordingly, the first voltage applying part 61 applies an organic light emitting layer (A) by applying a voltage smaller than the voltage applied by the second voltage part 62 to the second electrode layer 42 to the first electrode layer 41. A photocurrent is formed at 43, and the sensor unit 50 senses the amount of photocurrent generated in the organic light emitting layer 43, and determines that contact has occurred in the predetermined region when the photocurrent decreases in the predetermined region. As a result, a specific menu displayed on the display screen including the predetermined area is executed.

5A and 5B are schematic diagrams showing a voltage application method according to an embodiment of the present invention.

In the organic light emitting diode display, a method of applying a voltage to the electrode layers 41 and 42 of each pixel may be various, and FIGS. 5A and 5B are briefly illustrated to include all such methods.

As shown in FIG. 5A, the cathode electrode layer 42 may be integrally formed, and the anode electrode layer 41 may be formed for each pixel. In this case, since the magnitude of the voltage applied to the cathode electrode layer 42 by the second voltage applying unit 62 is constant, the size of each anode electrode layer 41 is adjusted by the first voltage applying unit 61. Thus, the polarities of the two electrode layers 41 and 42 can be adjusted.

For example, the voltage driving method may be simplified by applying a ground voltage to the second electrode layer 42 and applying a positive or negative voltage to the first electrode layer 41.

As shown in FIG. 5B, the cathode electrode layer 42 and the anode electrode layer 41 may be formed for each pixel. In this case, the voltage can be controlled separately for each electrode layer.

The hierarchical structure in which the polarity is adjusted in reverse according to an embodiment of the present invention may be inserted into a space between the light emitting pixels of the organic light emitting display, or may be implemented in the form of an area type.

Alternatively, a part of the light emitting pixels may be used as the hierarchical structure within the range not to drop the pixels of the entire organic light emitting display device.

6 is a schematic diagram illustrating a state in which a touch screen is applied and executed according to an embodiment of the present invention.

As shown in FIG. 6, when an external contact occurs in the organic light emitting diode display according to an exemplary embodiment of the present disclosure, a photocurrent of a predetermined region including a contact generation region decreases, and the sensor unit that detects the contact occurs. The determination is made so that a specific menu displayed on the display screen including the predetermined area is executed.

In FIG. 6, the display of the organic light emitting display device is divided into nine parts, and a menu icon is positioned in each divided area. When an external contact occurs, a menu part including the area ('5. ') Is activated and executed.

So far, the present invention has been described with reference to the preferred embodiments, and those skilled in the art to which the present invention pertains to the detailed description of the present invention and other forms of embodiments within the essential technical scope of the present invention. Could be implemented.

Here, the essential technical scope of the present invention is shown in the claims, and all differences within the equivalent range will be construed as being included in the present invention.

1 is a conceptual diagram of a general organic light emitting display device.

2A to 2B are conceptual views illustrating various hierarchical structures of a general organic light emitting display device.

3A and 3B are schematic views illustrating a principle of generating a photo current in an organic light emitting layer and implementing a touch screen using the same according to an embodiment of the present invention.

4 is a block diagram of an organic light emitting display device according to an embodiment of the present invention.

5A and 5B are schematic diagrams showing a voltage application scheme according to an embodiment of the present invention.

6 is a schematic diagram showing how a touch screen is executed, in accordance with an embodiment of the present invention.

Claims (11)

An organic light emitting display device including an anode, a cathode, and an organic light emitting layer interposed between the anode and the cathode to emit energy due to recombination of holes and electrons. And a predetermined area for adjusting the polarity of the anode and the cathode in reverse. The method of claim 1, And a polarity of the anode and the cathode by adjusting the magnitude of the voltage applied to the anode. The method of claim 2, And an polarity of the anode and the cathode is reversed by adjusting the magnitude of the voltage applied to the anode to be smaller than the voltage applied to the cathode. The method according to any one of claims 1 to 3, And a polarization of the anode and the cathode in the opposite direction to decompose the hole-electron pair in the organic emission layer to form a photocurrent. A substrate member; A first electrode layer formed on the substrate member; An organic light emitting layer formed on the first electrode layer and emitting energy due to recombination of holes and electrons; A second electrode layer formed on the organic light emitting layer; And A voltage controller configured to apply a voltage to the first electrode layer and the second electrode layer, And controlling the voltages of the first electrode layer and the second electrode layer to form a photocurrent in the organic light emitting layer by the voltage controller. The method of claim 5, And a sensor unit for sensing the amount of photocurrent formed in the organic light emitting layer. The method of claim 5, The voltage controller includes a first voltage applying unit applying a voltage to the first electrode layer and a second voltage applying unit applying a voltage to the second electrode layer. The method of claim 7, wherein A photocurrent is formed in the organic light emitting layer by adjusting a voltage applied to the first electrode layer by the first voltage applying unit to be smaller than a voltage applied to the second electrode layer by the second voltage applying unit. Organic light emitting display device. The method of claim 6, And the sensor unit determines that a contact has occurred in the predetermined region when the photocurrent in the predetermined region decreases. The method of claim 9, And determining that a contact has occurred in the predetermined region by the sensor unit, and executing a specific menu displayed on a display screen including the predetermined region. The method according to claim 5 or 6, And a ground voltage applied to the second electrode layer.

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