KR20080049910A - Organic light emitting device and method for fabricating the same - Google Patents

Abstract

An organic light emitting display device and a method for fabricating the same are provided to protect a second electrode and a light emitting layer from an external impact by forming a gap spacer of a predetermined height in a non-luminescent portion of a sub pixel area. An organic light emitting display device includes a substrate(300), first electrodes(340), a bank layer(352), and a gap spacer(354). The substrate includes a luminescent portion(A) and a non-luminescent portion(B). The first electrodes are positioned in the luminescent portion of the substrate. The bank layer is positioned in the non-luminescent portion of the substrate which exposes some of the first electrodes and insulates the first electrodes. The gap spacer is positioned in the non-luminescent portion of the substrate, which contains the same material as a material of the bank layer and has a thickness higher than the bank layer.

Description

Organic light emitting display device and manufacturing method thereof {ORGANIC LIGHT EMITTING DEVICE AND METHOD FOR FABRICATING THE SAME}

1A and 1B are cross-sectional views illustrating an organic light emitting display device according to the related art.

2A is a plan view illustrating an organic light emitting display device according to an embodiment of the present invention.

2B is a plan view illustrating a light emitting area, a non-light emitting area including a bank layer and a gap spacer according to an exemplary embodiment of the present invention.

FIG. 2C is a cross-sectional view taken along the line II ′ of FIG. 2B.

3A to 3F are cross-sectional views and perspective views illustrating a method of manufacturing an organic light emitting display device according to an embodiment of the present invention.

4 is a perspective view illustrating a method of applying an organic insulating material in a method of manufacturing an organic light emitting display device according to an embodiment of the present invention.

 <Description of the symbols for the main parts of the drawings>

A: light emitting area B: non-light emitting area

300: substrate 340: first electrode

352: bank layer 354: gap spacer

The present invention relates to an organic light emitting display device and a manufacturing method thereof.

Recently, a liquid crystal display device, an organic electroluminescence device, or a PDP (plasma display), which solves the shortcomings of the conventional display device, which are heavy and large, such as a cathode ray tube. A flat panel display device, such as a plane, is drawing attention.

At this time, since the liquid crystal display is not a light emitting device but a light receiving device, there is a limit in brightness, contrast, viewing angle, and large area, and although the PDP is a self-light emitting device, it is heavier than other flat panel display devices and consumes more weight. In addition to the high power and complicated manufacturing method, the organic light emitting display device is a self-luminous device, which is excellent in viewing angle, contrast, and the like. Is also advantageous.

In addition, the organic light emitting display device has a merit that DC low voltage driving is possible, the response speed is fast, it is resistant to external shock, the use temperature range is wide, and the manufacturing method is simple and inexpensive.

1A and 1B are cross-sectional views illustrating an organic light emitting display device according to the related art.

Referring to FIGS. 1A and 1B, the conventional organic light emitting display device 10 generally forms the display unit 15 including a plurality of subpixels on the device substrate 11, and the device substrate 11. ) And the encapsulation substrate 12 are sealed to protect the elements therein.

In this case, the subpixels of the device substrate 11 include at least a first electrode, a light emitting layer including a light emitting layer, and a second electrode, and the encapsulation substrate 12 includes a moisture absorbent 13 for absorbing moisture and the like. Is provided.

The encapsulation is made by the sealant 14 formed at the edge of the device substrate 11 and the encapsulation substrate 12. In this case, the sealant 14 is formed at a predetermined height so that the gap is maintained between the device substrate 11 and the encapsulation substrate 12.

However, since the interval that can be maintained by the sealant 14 is limited, the conventional organic light emitting display device 10 has a light emitting layer of the display unit 15 formed on the element substrate 11 when subjected to an external impact. Alternatively, the second electrode may be damaged, thereby degrading the image quality of the organic light emitting display device.

Accordingly, an object of the present invention is to provide an organic light emitting display device and a method of manufacturing the same, which can prevent a display unit of an organic light emitting display device from being damaged by an external impact.

In order to achieve the above object, the present invention provides a substrate including a light emitting region and a non-light emitting region, first electrodes positioned on a light emitting region of the substrate, and positioned on a non-light emitting region of the substrate, An organic light emitting display device includes a bank layer that exposes a portion of the first electrode and insulates the first electrodes, and a gap spacer disposed on a non-emission region of the substrate and including a same material as the bank layer and having a thickness higher than that of the bank layer. to provide.

The present invention also provides a method of preparing a device substrate including a light emitting region and a non-light emitting region, and forming a thin film transistor including a semiconductor layer, a gate insulating layer, a gate electrode, and a source / drain electrode on the non-light emitting region of the device substrate. Forming a passivation layer on the device substrate on which the thin film transistor is formed; forming first electrodes electrically connected to the source / drain electrodes on a light emitting region of the passivation layer; Applying an organic insulating material on the entire surface, exposing the organic insulating material using a halftone mask, and developing the exposed organic insulating material to expose a predetermined region of the first electrodes on the non-light emitting area Forming a bank layer that insulates the electrodes and a gap spacer having a thickness higher than the bank layer; Provides a method of manufacturing an organic electroluminescence display.

Details of the above object and technical configuration of the present invention and the effects thereof according to the present invention will be more clearly understood by the following detailed description with reference to the drawings showing preferred embodiments of the present invention.

2A to 2C are plan views and cross-sectional views illustrating an organic light emitting display device according to an embodiment of the present invention. 2A is a plan view illustrating an organic light emitting display device according to an embodiment of the present invention, and FIG. 2B illustrates a non-light emitting area including a light emitting area, a bank layer, and a gap spacer according to an embodiment of the present invention. FIG. 2C is a cross-sectional view taken along the line II ′ of FIG. 2B.

Referring to FIG. 2A, the organic light emitting display device of the present invention includes a device substrate 200 having a light emitting area A and a non-light emitting area B. FIG. In addition, a display unit 210, a sealing region 220 enclosing and encapsulating the display unit 210, and a pad unit 270 for inputting a signal or power to the display unit 210 are positioned on the device substrate 200. can do.

In this case, the display unit 210 includes a plurality of subpixels P of red (R), green (G), and blue (B).

In this case, the subpixel P is defined by the data line 230, the gate line 240, and the common power line 250. In other words, an area covered by the data line 230, the gate line 240, and the common power supply line 250 may be defined as a subpixel P.

In this case, the sub-pixel P may include a light emitting area A, and all regions on the substrate except for the light emitting area may be non-light emitting areas B. FIG. That is, the light emitting area A is an area where light is generated, and the non-light emitting area B is an area where no light is generated.

In addition, in a predetermined area of the non-light emitting area B, the power of the common power line 250 is controlled using the signals received from the data line 230 and the gate line 240 to control the light emitting area A. The sub pixel circuit area 260 is provided.

Although the sub-pixel circuit area 260 is illustrated as a non-emission area, when manufacturing an organic light emitting display device with a top emission type, the sub-pixel circuit area 260 may be formed under the emission area including the first electrode to improve the aperture ratio. .

Referring to FIG. 2B, the display unit 210 of the present invention, as described above, includes the light emitting area A and the non-light emitting area B except for the light emitting area A. The non-light emitting area B includes a bank layer 252 and a gap spacer 254.

In this case, the bank layer 252 serves to define the emission region A, and the gap spacer 254 maintains a constant gap of the entire device substrate 200 to prevent defects due to external pressing impact. It prevents it from happening.

Referring to FIG. 2C, the subpixel structure of the organic light emitting display device according to the exemplary embodiment will be described in detail.

The subpixel is provided on the device substrate 300 including the emission region A and the non-emission region B, the buffer layer 305 provided on the device substrate 300, and the buffer layer 305. A thin film transistor including a layer 310, a gate insulating film 315, a gate electrode 320, an interlayer insulating film 325, and a source / drain electrode 330.

In this case, the buffer layer 305 not only prevents the diffusion of impurities or foreign substances such as ions, moisture, oxygen, etc. from the lower device substrate 300 to the upper devices, and is formed on the semiconductor layer 310. Can be formed to improve the deposition characteristics or crystallization of the).

In this case, the thin film transistor may be a driving thin film transistor provided on the sub pixel circuit region 260 described with reference to FIG. 2A to provide a current to the first electrode 340. A transistor may be further provided. In addition, each of the gate electrode 320 and the source / drain electrode 330 of the thin film transistor may be formed of the same material or the same as the data line 230, the gate line 240, and the common power line 250 described with reference to FIG. 2A. It can be formed simultaneously in the process.

The subpixel is provided on the passivation layer 335 and the passivation layer 335 provided on the device substrate 300 provided with the thin film transistor, and is connected to the source / drain electrodes 330 of the thin film transistor. The first electrode 340 is disposed on the non-emission region B of the sub-pixel, and is disposed on the bank layer 352 and the non-emission region B formed to expose a portion of the first electrode 340. The gap spacer 354 is formed of the same material as the bank layer 352 and has a thickness thicker than that of the bank layer 352.

Here, the bank layer 352 may be formed to have a first thickness from the outer circumference of the light emitting region A to a predetermined width, and the gap spacer 354 may be formed to have a second thickness from the outer circumference of the bank layer 352 to a predetermined width. Can be.

In this case, the first thickness of the bank layer 352 is preferably 2 to 3 μm, because the bank layer 352 defines the emission region A. FIG. That is, the bank layer 352 prevents the first electrode 340 and the light emitting layer 360 (including the second electrode 370) from directly contacting the light emitting layer 360 as the first electrode 340. This prevents charge from moving and prevents light from being generated. In addition, the bank layer 352 serves to prevent the second electrode 370 provided on the bank layer 352 and other wirings or elements that may be provided directly under the bank layer from interfering with each other. .

In this case, it is preferable that the second thickness of the gap spacer 354 is 4 to 5 μm. The gap spacer 354 is encapsulated with an encapsulation substrate corresponding to the device substrate 300 and then the device substrate 300. ) And the encapsulation substrate to maintain a constant gap. That is, even when an external press impact or the like is applied to the surface of the encapsulation substrate, the light emitting layer 360 and the second light emitting layer 360 of the element substrate 300 of the device substrate 300 are formed by the encapsulation substrate by the gap spacer 354. The electrode 370 serves to prevent damage.

The light emitting layer 360 is positioned on the first electrode 340 exposed by the bank layer 352, and may include a second electrode 370 provided on the light emitting layer 360.

3A to 3F are cross-sectional views and perspective views illustrating a method of manufacturing an organic light emitting display device according to an embodiment of the present invention.

Referring to FIG. 3A, the method of manufacturing an organic light emitting display device according to the present invention first prepares a device substrate 300 in which a light emitting area A and a non-light emitting area B are defined.

In this case, the light emitting area A and the non-light emitting area B are already considered and determined in the design stage in manufacturing the organic light emitting display device.

In this case, the device substrate 300 may use a substrate made of a transparent material such as glass or plastic. In addition, if necessary, a substrate made of an opaque material such as sus or aluminum foil may be used.

Subsequently, a buffer layer 305 is formed on the device substrate 300. In this case, the buffer layer 305 may be formed using insulating films such as a silicon oxide film, a silicon nitride film, or a multilayer thereof, and serves to prevent diffusion of impurities from the device substrate 300 to devices to be formed later. do.

Subsequently, a semiconductor layer 310 is formed on the buffer layer 305. In this case, the semiconductor layer 310 may be formed by depositing amorphous silicon, crystallizing using a laser crystallization process, or the like, or by patterning the polysilicon directly on the buffer layer 305 and then patterning the semiconductor layer 310. have.

Subsequently, a gate insulating layer 315 is formed on the device substrate 300 on which the semiconductor layer 310 is formed. In this case, the gate insulating film 315 may be formed using an insulating film such as a silicon oxide film, a silicon nitride film, or a multilayer thereof. In this case, the gate insulating layer 315 is preferably formed so that a defect does not occur at the interface with the semiconductor layer 310.

Subsequently, the gate electrode 320 is formed on the gate insulating layer 315 to correspond to the channel region of the semiconductor layer 310.

In this case, after the gate electrode 320 is formed, an impurity implantation process is generally performed to form a channel region directly under the gate electrode 320, and the other semiconductor layer 310 may include a source region and a drain. To be an area.

Subsequently, an interlayer insulating layer 325 is formed on the device substrate 300 on which the gate electrode 320 is formed. In this case, the interlayer insulating layer 325 serves to protect the lower gate electrode 320 and the semiconductor layer 310.

Subsequently, a source electrode and a drain electrode 330 connected to the source and drain regions of the semiconductor layer 310 are formed on the interlayer insulating layer 325 to form the semiconductor layer 310, the gate insulating layer 315, and the gate. The thin film transistor including the electrode 320 is completed.

In this case, the thin film transistor may be provided in the sub pixel circuit region 260 described with reference to FIG. 2A. In this case, the thin film transistor may be used as a driving thin film transistor. In addition, although not shown in the sub-pixel circuit region 260 of FIG. 2A, a switch thin film transistor serving as a switch may be further provided, and a capacitor for storing charge may also be provided.

In this case, the lower electrode of the capacitor may be simultaneously formed when the gate electrode 320 is formed, and the lower electrode may be simultaneously formed when the source electrode and the drain electrode 330 are formed.

In addition, the data line 230 and the common power line 250 described with reference to FIG. 2A may be simultaneously formed when the source electrode and the drain electrode 330 are formed, and the gate line 240 is the gate electrode. It may be formed at the same time when forming (320).

Referring to FIG. 3B, after the thin film transistor is formed on the device substrate 300, the passivation layer 335 is formed on the entire surface of the device substrate 300. In this case, the passivation layer 335 not only serves to prevent interference between devices to be formed later, such as thin film transistors or data lines and gate lines, and the like. As a result, irregularities and the like are generated on the surface of the device substrate 300, which also serves to planarize the removal of the irregularities and the like.

Subsequently, a first electrode 340 connected to the source electrode and the drain electrode 330 of the thin film transistor is formed on the first passivation layer 335. In this case, the first electrode 340 is formed using a transparent conductive material such as ITO or IZO. In addition, the first electrode 340 may form a conductive material having good reflection characteristics such as aluminum or silver, if necessary. In general, an oxide conductive material such as ITO or IZO is preferably formed on the surface of the first electrode 340 in consideration of a work function of a light emitting layer to be formed later.

Referring to FIG. 3C, an organic insulating material 355 is coated on the device substrate 300 on which the first electrode 340 is formed.

In this case, the organic insulating material 355 is coated by scanning the entire surface of the device substrate 300 by using a coating apparatus having a slit nozzle. The organic insulating material 355 may be polyimide, benzocyclobutene or polyacrylic resin.

That is, as shown in FIG. 4, the device substrate 300 is charged into a coating apparatus (not shown) having a slit nozzle 400, and the slit nozzle 400 is scanned 410 in a predetermined direction. The organic insulating material 355 is sprayed 420 on the slit nozzle 400 and applied.

In this case, the method of coating the organic insulating material 355 on the entire surface of the device substrate 300 may include various methods including spin coating. However, in the present invention, since the bank layer and the gap spacer must be formed at the same time, the organic insulating material 355 ) Should be applied about 4 to 5 μm.

The coating method as described above has the advantage that the thickness uniformity is slightly worse compared to the coating method using a conventional spin coating apparatus, and is easy to apply to a large-area device substrate. It is economical because it is small.

Referring to FIG. 3D, after the device substrate 300 coated with the organic insulating material 355 is loaded into an exposure apparatus (not shown), the halftone mask 500 is aligned.

In this case, the halftone mask 500 is configured to form the light emitting region A and the non-light emitting region B including the bank layer 352 and the gap spacer 354 of the organic light emitting display device of the present invention. The transmissive region 510, the transflective region 520, and the blocking region 530 are previously designed at predetermined positions.

Subsequently, an exposure process 550 is performed by irradiating light such as ultraviolet rays onto the entire surface of the device substrate 300 where the halftone mask 500 is aligned.

In this case, by the exposure process 550, the entire area under the transparent region 510 of the halftone mask 500 and the predetermined depth under the semi-transmissive region 520 of the organic insulating material 355 may be applied. The area of will change its characteristics.

Referring to FIG. 3E, an organic insulating material on the first electrode 340 of the emission area A may be formed by performing a developing process of removing a region of which the characteristic is changed among the organic insulating materials subjected to the exposure process 550. Is completely removed to expose a predetermined region of the first electrode 340, and the organic insulating layer has a predetermined depth from the edge (that is, the outer periphery) of the light emitting region A to the predetermined width of the non-light emitting region B. The material is removed to form a bank layer 352 having a first thickness, and the non-emitting region B except for the bank layer 352 forms a gap spacer having a second thickness.

In this case, the first thickness of the bank layer 352 may be formed to 2 to 3㎛. In this case, the first thickness is related to the thickness of the organic insulating material itself and the transmittance of the semi-transmissive region of the halftone mask. That is, the thicker the thickness of the organic insulating material itself and the lower the transmittance, the thicker the first thickness may be.

In this case, the second thickness of the gap spacer 354 may be formed to 4 to 5㎛. In this case, the second thickness is related to the thickness of the organic insulating material itself. That is, the thicker the thickness of the organic insulating material itself is, the thicker the second thickness becomes.

Accordingly, the first thickness of the bank layer 352 and the second thickness of the gap spacer 354 may be easily controlled by adjusting the thickness of the organic insulating material itself and the transmittance of the transflective region.

Referring to FIG. 3F, the light emitting layer 360 is formed on the device substrate 300. The emission layer 360 may include an organic material. In this case, a lower portion and an upper portion of the light emitting layer 360 may further include a hole injection layer, a hole transport layer, an electron transport layer and an electron injection layer.

Subsequently, a second electrode 370 is formed on the emission layer 360. In this case, the second electrode 370 may be formed of a metal material such as magnesium or silver. In this case, the second electrode 370 may be formed as a transflective electrode in consideration of a work function or light transmittance, or alternatively, may be formed to include a metal film and a transparent conductive film such as ITO or IZO.

An encapsulation substrate (not shown) corresponding to the device substrate 300 is prepared, and the device substrate 300 and the encapsulation substrate are encapsulated in the same manner as the conventional method to manufacture an organic light emitting display device.

As described above, the present invention can shorten the manufacturing process by simultaneously forming the bank layer and the gap spacer. In addition, when the bank layer and the gap spacer are formed, a coating method using a slit nozzle may be performed to reduce the consumption of materials and to secure a coating thickness necessary for forming the bank layer and the gap spacer.

The present invention has been shown and described with reference to the preferred embodiments as described above, but is not limited to the above embodiments and those skilled in the art without departing from the spirit of the present invention. Various changes and modifications will be possible.

Accordingly, the organic light emitting display device and the manufacturing method thereof according to the present invention include a gap spacer having a predetermined height on the non-emission area of the sub pixel area, thereby providing a second electrode on the emission area of the sub pixel area and at least a light emitting layer. There is an effect that the light emitting layer can protect from an external impact such as externally pressed.

Claims (10)

A substrate comprising a light emitting area and a non-light emitting area; First electrodes on the emission region of the substrate; A bank layer on the non-light emitting region of the substrate, the bank layer exposing a portion of the first electrodes and insulating the first electrodes; And An organic light emitting display device on a non-emission region of the substrate, the organic light emitting display device comprising a gap spacer including the same material as a bank layer and having a thickness higher than that of the bank layer. The method of claim 1, The bank layer and the gap spacer are made of an organic insulating material. The method of claim 2, The organic insulating material is any one selected from the group consisting of polyimide, benzocyclobutene and polyacryl. The method of claim 1, An organic light emitting display device comprising a light emitting layer on the first electrode and a second electrode on the light emitting layer. The method of claim 4, wherein An organic light emitting display device further comprising a thin film transistor electrically connected to the first electrode. Preparing a device substrate in which a light emitting area and a non-light emitting area are defined; Forming a thin film transistor including a semiconductor layer, a gate insulating film, a gate electrode, and a source / drain electrode on a non-light emitting region of the device substrate; Forming a passivation layer on the device substrate on which the thin film transistor is formed; Forming first electrodes on the light emitting region of the passivation layer, the first electrodes electrically connected to the source / drain electrodes; Applying an organic insulating material on an entire surface of the device substrate on which the first electrode is formed; Exposing the organic insulating material using a halftone mask; And Developing the exposed organic insulating material to form a bank layer exposing a predetermined region of the first electrodes and insulating the first electrodes on the non-light emitting region and a gap spacer having a thickness higher than the bank layer; Method of manufacturing an organic light emitting display device comprising a. The method of claim 6, And sequentially forming a light emitting layer and a second electrode on the exposed first electrodes. The method of claim 6, The method of manufacturing an organic light emitting display device is performed by coating an organic insulating material on a device substrate on which the first electrode is formed by scanning the entire surface of the device substrate using a coating device having a slit nozzle. The method according to claim 7 or 8, After forming the second electrode, And preparing an encapsulation substrate to face the element substrate, and encapsulating the element substrate and the encapsulation substrate by a sealant. The method of claim 6, The organic insulating material is any one selected from the group consisting of polyimide, benzocyclobutene and polyacrylic.

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