KR20080003057A - Organic electro luminescence display device - Google Patents

Abstract

An organic electro luminescence display device is provided to prevent a spacer from being damaged by forming an additional ball spacer or a column spacer. A first substrate(110) and a second substrate(120) are provided. A thin film transistor is formed on the first substrate. A preliminary electrode(122) defining a plurality of pixel regions is arranged on the second substrate having a stripe shape. In the pixel region, organic luminescent layers(123(R,G,B)) are inserted into a first electrode(121) and a second electrode(122). A first spacer(130) connects the thin film transistor and the second electrode. A second spacer is formed between both substrates.

Description

Organic electroluminescent display device {ORGANIC ELECTRO LUMINESCENCE DISPLAY DEVICE}

1 is a cross-sectional view schematically showing a conventional organic light emitting display device.

2 is a plan view showing in detail the unit pixels of a conventional organic light emitting display device.

3 is a cross-sectional view showing a cross-section taken along line II ′ of FIG. 2.

4 is a cross-sectional view illustrating an organic light emitting display device of a dual plate type according to an embodiment of the present invention.

5 is a cross-sectional view illustrating an organic light emitting display device of a dual plate type according to another embodiment of the present invention.

*** Explanation of symbols for main parts of drawing ***

110,120: first substrate 121,125: first electrode

122: auxiliary electrode 123,223: organic light emitting layer

130: spacer 131: partition wall

142: ball spacer

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic light emitting display device, and more particularly, to a dual plate type organic electroluminescent display device capable of improving brightness by maximizing light efficiency.

Since the organic light emitting display device is a self-luminous type, the viewing angle is wider, the contrast is higher, and the visibility is superior to that of the liquid crystal device. In addition, since the backlight is unnecessary, the device can be made thinner and lighter, and it is advantageous in terms of power consumption in comparison with LCDs which always need to illuminate the backlight in front of the display regardless of the display content since the current needs to be sent only to pixels requiring light emission. .

In addition, DC low voltage driving, fast response speed and easy moving picture display are attracting attention as the next generation flat panel display.

1 is a cross-sectional view schematically showing a configuration of a conventional organic light emitting display device.

As shown in the drawing, the organic light emitting display device 10 includes a thin film transistor array T on the transparent first substrate 12 and a first electrode 16 on the thin film transistor array T. ) And an organic light emitting layer 18 and a second electrode 19.

In this case, the emission layer 18 expresses red (R), green (G), and blue (B) colors. In general, a separate organic material that emits red and green blue for each pixel (P). Is patterned and formed.

The first substrate 12 is bonded to the second substrate 28 having the hygroscopic agent 22 attached thereto through the seal 26, thereby completing the encapsulated organic light emitting display device 10.

At this time, the moisture absorbent 22 is for removing moisture and oxygen that can penetrate the inside of the capsule, by etching a portion of the substrate 28 to fill the etched absorbent 22 and fixed with a tape (25).

2 and 3 are enlarged views of the unit pixels of the thin film transistor array unit, FIG. 2 is a plan view, and FIG. 3 is a cross-sectional view taken along line II ′ of FIG. 2.

As shown in the figure, the thin film transistor array unit includes a switching element Ts, a driving element Td, and a storage capacitor Cst for each of the plurality of pixels defined in the substrate 12. The switching element Ts or the driving element Td may be formed of a combination of one or more thin film transistors, respectively.

In addition, a gate line 32 arranged in one direction and a data line 34 intersecting each other with the gate line 32 and the insulating layer 57 ′ interposed therebetween are arranged on the substrate 12. A power supply line 35 is arranged to be spaced parallel to 34 and intersect the gate line 32.

The switching element Ts and the driving element Td include a thin film including gate electrodes 36 and 38, active layers 40 and 42, and source electrodes 46 and 52 and drain electrodes 50 and 56. Transistors are used. In this case, the drain electrode 50 of the switching element Ts is connected to the gate electrode 38 of the driving element Td through the contact hole 54 and the source electrode 52 of the driving element Td. ) Is connected to the power line 35 through a contact hole 55. In addition, the drain electrode 56 of the driving device Td is connected to the first electrode 16 formed in the pixel portion P.

The storage capacitor Cst is formed by the power supply wiring 35, the polycrystalline silicon pattern 15, and an insulating layer 57 interposed therebetween.

On the other hand, the configuration in more detail through the cross-sectional view, the driving element Td is composed of a gate electrode 38, an active layer 42, a source electrode 52 and a drain electrode 56, the driving element Above the Td, the first electrode 16 contacting the drain electrode 56 of the driving element Td with the insulating film 57 therebetween, and the light having the characteristic color on the first electrode 16 The organic light emitting device 20 is composed of a light emitting layer 18 to be generated and a second electrode 19 formed on the light emitting layer 18.

In the conventional organic light emitting display device configured as described above, the organic light emitting device 20 including the first electrode 16, the light emitting layer 18, and the second electrode 19 includes the first electrode 16 and the second electrode. According to the transparency of the electrode 19, it is divided into a bottom emission (top emission) and a top emission (top emission).

The bottom emission type is stable during the encapsulation process of the organic light emitting device, and has a high degree of freedom in the process, and has a problem in that it is difficult to apply to high-resolution products due to the limitation of the aperture ratio.

In addition, the top emission type has a long lifetime because of the high degree of freedom in designing the thin film transistor and the improvement of the aperture ratio, but the transmittance is limited because the selection width of the material is narrow as the cathode is usually positioned on the organic light emitting layer. In this case, when the thin film type protective film for minimizing the degradation of the light transmittance is to be reduced, there is a problem that the outside air cannot be sufficiently blocked.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a dual plate type organic light emitting display device in which a thin film transistor array unit and an organic light emitting device are formed on a separate substrate and then bonded to each other.

Another object of the present invention is to provide an organic light emitting display device which can prevent the spacer from being broken by dispersing this pressure when a pressure is applied from the outside.

In order to achieve the above object, the organic light emitting display device according to the present invention, a first substrate and a second substrate, a thin film transistor formed on the first substrate, and a plurality of pixels arranged in a grid form on the second substrate An organic light emitting element comprising an auxiliary electrode defining a region, an organic light emitting layer in the pixel region, a first electrode and a second electrode, and an organic light emitting layer interposed therebetween, a thin film transistor of the first substrate and a second of the second substrate A first spacer electrically connecting the electrode, and a second spacer formed between the first substrate and the second substrate.

The second spacer is formed of a ball spacer or a column spacer to disperse the pressure applied from the outside.

The present invention provides an organic light emitting display device having a novel structure. The new organic light emitting display device is a dual ORGANIC electroluminescence display device, adopting the advantages of the bottom emission type and the top emission type, has the advantage of stabilization and improved aperture ratio during the encapsulation process. In addition, in the present invention, an electrode having good reflectance is disposed between the pixel and the pixel to reflect the light that is improved to the side, thereby improving the front luminance.

Hereinafter, an organic light emitting display device according to the present invention will be described in more detail with reference to the accompanying drawings.

4 is a cross-sectional view illustrating an organic light emitting display device according to an embodiment of the present invention.

As shown in FIG. 4, the organic light emitting display device 100 of the present invention includes a first substrate 110 on which a thin film transistor array is formed, and an organic light emitting diode EL. The second substrate 120 is composed of.

The first substrate 110 includes a switching element (not shown) made of a thin film transistor and a driving element Td, and an array wiring (not shown) for applying a signal to the thin film transistor is formed.

The thin film transistor, which is the driving element Td, includes a gate electrode 101, an active layer 103, a source electrode 105a, and a drain electrode 105b, and the gate electrode 101 and the active layer 103. ) Is interposed between the gate insulating film 102 for insulation therebetween. In addition, a passivation layer 106 is formed over the entire surface of the first substrate 110 including the source electrode 105a and the drain electrode 105b, and the passivation layer 106 exposes a part of the drain electrode 105b. Let's do it.

In addition, a metal pattern 107 in electrical contact with the drain electrode 105b is formed on the passivation layer 106.

An auxiliary electrode 122 defining a pixel region is formed in the second substrate 120 in a lattice structure (matrix form), and organic light emitting elements EL (R) and EL (G) are formed in each pixel region P. ), EL (B)) is formed. The organic light emitting diodes EL (R), EL (G), and EL (B) are interposed between the first electrode 121 and the second electrode 125 and between the first and second electrodes 121 and 125. And an organic light emitting layer 123 (R), 123 (G), and 123 (B). The auxiliary electrode 122 is formed on the first electrode 121.

The first electrode 121 is formed over the entire surface of the second substrate 120, and the second electrode 125 is a drain electrode 105b of the driving element Td formed on the second substrate 120. Is electrically connected to the In this case, the second electrode 125 is electrically connected to the driving device Td by the metal pattern 107 connected to the drain electrode 105b through the spacer 130.

In addition, the first electrode 121 may be formed of a transparent electrode such as indium tin oxide (ITO), and the second electrode 125 may include calcium (Ca), aluminum (Al), and magnesium (Mg). It may be formed of one of the metals. The first electrode 121 is an anode electrode for injecting holes into the organic light emitting layers 123 (R), 123 (G), and 123 (B), and the second electrode 125 is the organic It may be a cathode electrode for injecting electrons into the light emitting layers 123 (R), 123 (G), and 123 (B).

Although not illustrated, the organic light emitting layers 123 (R), 123 (G), and 123 (B) include a hole transport layer, a light emitting layer, and an electron transport layer. The transport layer and the electron transport layer help to smoothly inject holes and electrons supplied from the first and second electrodes 121 and 125 into the organic light emitting layers 123 (R), 123 (G), and 123 (B).

Meanwhile, a buffer layer 124 is formed on the auxiliary electrode 122, a lattice-shaped partition wall 131 is formed on the buffer layer 124, and the partition wall 131 is a boundary area of the pixel area P. And substantially define the pixel region P. In FIG.

In addition, a ball spacer 142 is disposed between the partition wall 131 and the first substrate 110. The ball spacer 142 is made of glass fiber and resin, and is dispersed on the first substrate 110 or the second substrate 120 before the first substrate 110 and the second substrate 120 are bonded to each other. Form.

The reason why the ball spacer 142 is disposed between the first substrate 110 and the second substrate 120 is as follows.

As shown in FIG. 4, in the organic light emitting display device 100 of the present invention, a spacer 130 is formed on the second substrate 120, so that a gap between the first substrate 110 and the second substrate 120 is formed. Keep it constant. However, in the organic light emitting display device 100 having such a configuration, when a pressure is applied from the outside such as an operator touching the screen, the spacer 130 made of acrylic material is damaged by the pressure. In particular, in the case of a display device which performs a task by touching a screen that provides a touch panel function to the flat panel display itself, the spacer 130 is damaged because external pressure is continuously applied.

Breakage of the spacer 130 not only causes a problem that the gap between the first substrate 110 and the second substrate 120 is not kept constant, but also causes electrical failure between the first substrate 110 and the second substrate 120. Since the contact also causes a problem of poor contact, the organic light emitting display device 100 is the main cause of the poor.

However, by providing a ball spacer 142 between the first substrate 110 and the second substrate 120 as in the present invention, the spacer 130 is broken by dispersing the external pressure applied to the spacer 130. Can be prevented. In this case, the ball spacer 142 may be located below the partition wall 131 of the second substrate 120, as shown in Figure 4, but any gap between the first substrate 110 and the second substrate 120. It could be located somewhere.

On the other hand, the present invention is not limited to such a ball spacer 142. As shown in FIG. 5, the external force applied to the spacer 230 may be dispersed by forming the column spacer 242 at a predetermined position. The column spacer 242 is formed of an inorganic material or an organic material. Since the column spacer 242 is formed by a photolithography process, the column spacer 242 may be formed at an accurate location.

Meanwhile, in the above description, the structure of the organic light emitting display device of the present invention is described as a specific structure, but this is for convenience of description and is not intended to limit the present invention. For example, although the auxiliary electrode is formed on the second substrate and the first electrode is formed on the auxiliary electrode in the drawing, the auxiliary electrode may be formed on the first electrode, but the configuration except for the auxiliary electrode may be possible. In addition, the structure of the partition wall, etc. will be possible in various forms.

Accordingly, the scope of the invention should be determined by the appended claims rather than by the foregoing description.

As described above, in the present invention, a separate ball spacer or column spacer may be formed to prevent the spacer from being damaged by an external force such as a touch.

Claims (10)

A first substrate and a second substrate; A thin film transistor formed on the first substrate; An auxiliary electrode arranged on the second substrate in a lattice form to define a plurality of pixel regions; An organic light emitting element comprising a first electrode, a second electrode, and an organic light emitting layer interposed therebetween in the pixel region; A first spacer electrically connecting the thin film transistor of the first substrate and the second electrode of the second substrate; An organic light emitting display device comprising a second spacer formed between the first substrate and the second substrate. The method of claim 1, A buffer layer formed on the auxiliary electrode; And An organic light emitting display device, characterized in that it further comprises a partition formed on the buffer layer. The method of claim 1, The thin film transistor, A gate electrode formed on the first substrate, A gate insulating film formed on an entire surface of the first substrate including the gate electrode; A semiconductor layer formed on the gate insulating film; And An organic light emitting display device comprising: a source / drain electrode formed on the semiconductor layer. The organic light emitting display device of claim 3, further comprising a metal pattern exposing a part of the drain electrode on a first substrate including a source electrode and a drain electrode. The organic light emitting display device of claim 4, wherein the metal pattern is electrically connected to the second electrode through the first spacer. The organic light emitting display device of claim 1, wherein the first electrode is a transparent electrode, and the second electrode is an opaque electrode. The organic light emitting display device of claim 1, wherein the first electrode formed in each pixel area is electrically connected to the auxiliary electrode. The organic light emitting display device of claim 1, wherein the auxiliary electrode and the pixel electrode are formed on a first substrate. The organic light emitting display device of claim 1, wherein the second spacer is a ball spacer. The organic light emitting display device of claim 1, wherein the second spacer is a column spacer.

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