KR20070054051A - Method of manufacturing display device - Google Patents

Abstract

The present invention relates to a method of manufacturing a display device. Method of manufacturing a display device according to the present invention comprises the steps of forming a thin film transistor on an insulating substrate; Forming a pixel electrode electrically connected to the thin film transistor; Attaching a partition member having an opening so that the opening corresponds to the pixel electrode; Forming an organic layer on the pixel electrode exposed by the opening;

Forming a common electrode on the organic layer and the partition member. As a result, the barrier layer can be easily formed, thereby providing a manufacturing method of a display device having high manufacturing efficiency.

Description

Manufacturing method of display device {METHOD OF MANUFACTURING DISPLAY DEVICE}

1 is an equivalent circuit diagram of a pixel of a display device manufactured according to an embodiment of the present invention;

2 is a cross-sectional view of a display device manufactured according to an embodiment of the present invention, and

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

Explanation of symbols on the main parts of the drawings

1: Display Device 10: Insulation Board

20: thin film transistor 31: protective film

32: pixel electrode 40: partition member

41: opening 50: organic layer

51: hole injection layer 52: light emitting layer

61: common electrode 100, 200: inkjet nozzle

The present invention relates to a method for manufacturing a display device, and more particularly, to a method for manufacturing a display device for attaching a separately prepared partition member to form a partition layer.

Among flat panel displays, organic light emitting diodes (OLEDs) have recently been in the spotlight due to advantages such as low voltage driving, light weight, wide viewing angle, and high speed response. OLEDs are classified into a passive matrix and an active matrix according to the driving method. The passive type has a simple manufacturing process, but the power consumption increases rapidly as the display area and resolution increase. Therefore, the passive type is mainly applied to small displays. Active type, on the other hand, has a complex manufacturing process but has the advantage of realizing a large screen and high resolution.

In the active OLED, a thin film transistor is connected to each pixel region to control light emission of the organic light emitting layer for each pixel region. Pixel electrodes are located in each pixel area, and each pixel electrode is electrically separated from adjacent pixel electrodes for independent driving. An organic layer such as a hole injection layer and an organic light emitting layer is present on the pixel electrode.

The organic layer is usually formed by an inkjet method. In the inkjet method, an ink in which an organic substance is dissolved on a pixel electrode is dripped, and then the ink is dried to form an organic layer. The partition layer surrounding the pixel electrode is formed.

The barrier layer is formed through a photo process. First, a barrier layer (not shown) including a photosensitive material is formed on the pixel electrode by slit coating or spin coating. Then, the barrier layer is exposed and developed and subjected to a cleaning process to complete the barrier layer.

Since the photo process for forming the barrier layer has to go through a process of coating, exposure, development and cleaning in sequence, there is a problem in that manufacturing time and manufacturing cost increase in manufacturing a display device, thereby lowering manufacturing efficiency.

Accordingly, it is an object of the present invention to provide a method for manufacturing a display device, which can easily form a partition layer and has high manufacturing efficiency.

The object is, according to the present invention, forming a thin film transistor on an insulating substrate; Forming a pixel electrode electrically connected to the thin film transistor; Attaching a partition member having an opening so that the opening corresponds to the pixel electrode; Forming an organic layer on the pixel electrode exposed by the opening; And forming a common electrode on the organic layer and the partition member.

The method may further include forming a passivation layer on the thin film transistor between the forming of the thin film transistor and the forming of the pixel electrode.

The method may further include oxygen plasma treatment of the pixel electrode between attaching the partition member and forming the organic layer.

The partition member is preferably made of PDMS (polydimethylsiloxane).

The organic layer preferably includes a hole injection layer and a light emitting layer that are sequentially formed.

The organic layer is characterized in that formed by the inkjet method.

Hereinafter, the present invention will be described with reference to the accompanying drawings. Note that the display device manufactured by the embodiment of the present invention is an organic light emitting diode (OLED). In the description, 'on' or 'on' means that another layer (membrane) is interposed or not interposed between the two layers (membrane), and 'just on' indicates that the two layers (membrane) are in contact with each other.

1 is an equivalent circuit diagram of a pixel in a display device manufactured according to the present invention.

A plurality of signal lines are provided in one pixel. The signal line includes a gate line for transmitting a scan signal, a data line for transmitting a data signal, and a driving voltage line for transmitting a driving voltage. The data line and the driving voltage line are adjacent to each other and disposed side by side, and the gate line extends perpendicular to the data line and the driving voltage line.

Each pixel includes an organic light emitting element LD, a switching thin film transistor Tsw, a driving thin film transistor Tdr, and a capacitor C.

The driving thin film transistor Tdr has a control terminal, an input terminal, and an output terminal. The control terminal is connected to the switching thin film transistor Tsw, the input terminal is connected to a driving voltage line, and the output terminal is an organic light emitting diode ( LD).

The organic light emitting element LD has an anode connected to the output terminal of the driving thin film transistor Tdr and a cathode connected to the common voltage Vcom. The organic light emitting element LD displays an image by emitting light having a different intensity according to the output current of the driving thin film transistor Tdr. The current of the driving thin film transistor Tdr varies in magnitude depending on the voltage applied between the control terminal and the output terminal.

The switching thin film transistor Tsw also has a control terminal, an input terminal and an output terminal, the control terminal is connected to the gate line, the input terminal is connected to the data line, and the output terminal of the driving thin film transistor Tdr. It is connected to the control terminal. The switching thin film transistor Tsw transfers a data signal applied to the data line to the driving thin film transistor Tdr according to a scan signal applied to the gate line.

The capacitor C is connected between the control terminal and the input terminal of the driving thin film transistor Tdr. The capacitor C charges and maintains a data signal input to the control terminal of the driving thin film transistor Tdr.

A display device manufactured according to the present invention will be described with reference to FIG.

The display device 1 manufactured according to the present invention includes a thin film transistor 20 formed on an insulating substrate 10, a pixel electrode 32 and a pixel electrode 32 electrically connected to the thin film transistor 20. A partition member 40 attached to the upper surface, an organic layer 50 formed on the pixel electrode 32 not covered by the partition member 40, and a common electrode 61 formed on the organic layer 50. Include.

In the figure, although the thin film transistor 20 using amorphous silicon is illustrated, a thin film transistor using polysilicon may be used.

Looking at the display device (1) manufactured according to the present invention in detail.

The gate electrode 21 is formed on an insulating substrate 10 made of an insulating material such as glass, quartz, ceramic, or plastic.

A gate insulating layer 22 made of silicon nitride (SiNx) or the like is formed on the insulating substrate 10 and the gate electrode 21. A semiconductor layer 23 made of amorphous silicon and an ohmic contact layer 24 made of n + hydrogenated amorphous silicon heavily doped with n-type impurities are sequentially formed on the gate insulating film 22 where the gate electrode 21 is located. Here, the ohmic contact layer 24 is separated on both sides with respect to the gate electrode 21.

The source electrode 25 and the drain electrode 26 are formed on the ohmic contact layer 24 and the gate insulating film 22. The source electrode 25 and the drain electrode 26 are separated around the gate electrode 21.

The passivation layer 31 is formed on the source electrode 25, the drain electrode 26, and the semiconductor layer 23 not covered by these. The passivation layer 31 may be formed of silicon nitride (SiNx) and / or an organic layer. The protective film 31 is provided with a contact hole 27 exposing the drain electrode 26.

The pixel electrode 32 is formed on the passivation layer 31. The pixel electrode 32 is also called an anode and supplies holes to the emission layer 52. The pixel electrode 32 is made of a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO), and is formed by a sputtering method. The pixel electrode 32 may be patterned in a substantially rectangular shape in plan view.

The partition member 40 is attached to each pixel electrode 32. The partition member 40 defines a pixel region by dividing the pixel electrodes 32, and is formed on the thin film transistor 20 and the contact hole 27. The partition member 40 also serves to prevent the source electrode 25 and the drain electrode 26 of the thin film transistor 20 from being short-circuited with the common electrode 61. The partition member 40 is not formed through a photo process in this embodiment, but is manufactured separately and then attached to the upper portion of the passivation layer 31 and the pixel electrode 32 to form a partition layer. The partition member 40 includes a thermosetting resin or an ultraviolet curable resin. In this embodiment, the partition member 40 includes a polydimethylsiloxane (PDMS), which is one of the thermosetting resins.

PDMS (polydimethylsiloxane) is an elastomer having a molecular weight of 162.38, a boiling point of 205 캜 and a density of 0.76 g / ml. PDMS (polydimethylsiloxane) is inert, has characteristics of flexibility, lubricity, hydrophobicity, and strong durability, and can be stably attached in a relatively large area to a substrate, and can be easily attached to an unplanned surface.

A hole injecting layer 51 and a light emitting layer 52 are positioned on the pixel electrode 32 not covered by the partition member 40.

As the hole injection layer 51, a mixture of polythiophene derivatives such as poly (3,4-ethylenedioxythiophene) (PEDOT) and polystyrene sulfonic acid (PSS) can be used.

The light emitting layer 52 includes a red light emitting layer 52a for emitting red light, a green light emitting layer 52b for emitting green light, and a blue light emitting layer 52c for emitting blue light.

The light emitting layer 52 may be formed of a perylene-based dye, a rhomine-based dye, or a polyfluorene derivative, a (poly) paraphenylene vinylene derivative, a polyphenylene derivative, a polyvinylcarbazole, a polythiophene derivative, or a polymer material thereof. Bren, perylene, 9,10-diphenylanthracene, tetraphenylbutadiene, nile red, coumarin 6, quinacridone and the like can be used.

Holes transferred from the pixel electrode 32 and electrons transferred from the common electrode 61 are combined in the emission layer 52 to form excitons, and then light is generated during the deactivation of the excitons.

The hole injection layer 51 and the light emitting layer 52 are formed to have a uniform thickness regardless of the distance to the partition member 40. As a result, the shorting of the pixel electrode 32 and the common electrode 61 through the portion where the organic layer 50 is not formed is reduced.

The common electrode 61 is positioned on the partition member 40 and the light emitting layer 52. The common electrode 61 is also called a cathode and supplies electrons to the light emitting layer 52. The common electrode 61 may be formed by stacking a calcium layer and an aluminum layer. At this time, a calcium layer having a low work function is preferably disposed on the side close to the light emitting layer 52.

Since lithium fluoride increases the luminous efficiency depending on the material of the light emitting layer 52, a lithium fluoride layer may be formed between the light emitting layer 52 and the common electrode 61. When the common electrode 61 is made of an opaque material such as aluminum or silver, the light emitted from the light emitting layer 52 is emitted toward the insulating substrate 10, which is referred to as a bottom emission method.

Although not shown, the display device 1 may further include an electron transfer layer and an electron injection layer between the emission layer 52 and the common electrode 61. In addition, a protective film for protecting the common electrode 61, an encapsulation member (not shown) for preventing the penetration of moisture and air into the organic layer 50 may be further included. The sealing member may be formed of a sealing resin and a sealing can.

Hereinafter, a method of manufacturing a display device according to an exemplary embodiment of the present invention will be described with reference to FIGS. 3A to 3F.

First, as shown in FIG. 3A, the thin film transistor 20, the passivation layer 31, and the pixel electrode 32 are sequentially formed on the insulating substrate 10.

The thin film transistor 20 has a channel portion made of amorphous silicon and may be manufactured by a known method.

After the thin film transistor 20 is formed, the passivation layer 31 is formed on the thin film transistor 20. When the protective layer 31 is silicon nitride, chemical vapor deposition may be used. After that, the protective layer 31 is photo-etched to form a contact hole 27 exposing the drain electrode 26. After forming the contact hole 27, the pixel electrode 32 connected to the drain electrode 26 is formed through the contact hole 27. The pixel electrode 32 may be formed by depositing and patterning ITO by sputtering.

Thereafter, as shown in FIG. 3B, the partition member 40 having the opening 41 is aligned so that the opening 41 is aligned with the pixel electrode 32, and then attached to the insulating substrate 10. The partition member 40 is prepared by injecting a partition member forming material including PDMS (polydimethylsiloxane) into the molding mold by an injection method and then cooling it. The opening 41 of the partition member 40 is formed to be slightly smaller than the size of the pixel electrode 32 corresponding thereto.

The partition member 40 including PDMS (polydimethylsiloxane) has excellent durability, flexibility, and adhesion, and when applied under pressure, the partition member 40 is stably in a large area with the protective layer 31 and the pixel electrode 32 on the insulating substrate 10. Attachment can be fixed. In addition, there is an advantage that can be easily attached to the stepped surface. If necessary in the attachment process it is also possible to attach the insulating substrate 10 by applying an adhesive to the attachment surface of the partition member 40 to increase the fixing force.

FIG. 3C is a cross-sectional view of the display device during manufacture in which the partition member 40 is attached to the insulating substrate 10. The opening 41 of the barrier rib member 40 that is attached exposes an upper portion of the pixel electrode 32 provided in the pixel region.

Thereafter, an oxygen plasma treatment is performed on the upper surface of the pixel electrode 32 using an oxygen plasma processing apparatus (not shown). The reason for the oxygen plasma treatment is that when the hole injection solution 51 is dropped using the inkjet printing method in the process of forming the hole injection layer 51, the hole injection solution 51 is formed on the pixel electrode 32. This is to improve the surface property of the pixel electrode 32 so as to spread evenly on the upper surface.

Meanwhile, the partition member 40 including the PDMS (polydimethylsiloxane) according to the embodiment of the present invention is a material having water repellency and oil repellency from the hole injection solution 55 and the light emitting solution 56, and thus, separate CF4. There is an advantage that no plasma treatment is required.

Thereafter, to form the hole injection layer 51, a hole injection solution 55, which is a polymer solution containing a hole injection material, is dropped onto the pixel electrode 32 through the inkjet nozzle 100 as shown in FIG. 3D. The hole injection solution 55 may include a mixture of polythiophene derivatives such as poly (3,4-ethylenedioxythiophene) (PEDOT) and polystyrene sulfonic acid (PSS), and a polar solvent in which these mixtures are dissolved. . As a polar solvent, for example, isopropyl alcohol (IPA), n-butanol, γ-butylollactone, N-methylpyridone (NMP), 1,3-dimethyl-2-imidazolidinone (DMI) And glycol ethers such as derivatives thereof, carbitol acetate and butyl carbitol acetate, and the like.

Thereafter, when the hole injection solution 55 is dried, a hole injection layer 51 having a uniform thickness may be formed. The hole injection solution 55 can be dried by lowering the pressure to about 1 Torr at room temperature under a nitrogen atmosphere. If the pressure is too low, there is a risk that the hole injection solution 55 breaks rapidly. On the other hand, when the temperature is higher than or equal to room temperature, the solvent evaporation rate increases, which makes it difficult to form a film of uniform thickness, which is not preferable.

After the drying is completed, heat treatment may be performed for about 10 minutes at about 200 ° C. in nitrogen, preferably in vacuum, and the solvent or water remaining in the hole injection layer 51 is removed through this process.

Thereafter, as shown in FIG. 3E, the light emitting solution 56, which is a polymer solution containing a light emitting material, is dropped through the inkjet nozzle 200 to form the light emitting layer 52 on the hole injection layer 51. The inkjet nozzles 200 are provided with red, green, and blue inkjet nozzles 200a, 200b, and 200c for discharging the red, green, and blue light emitting solutions 56a, 56b, and 56c, respectively, and are alternately red, green, and blue in each pixel area. The blue light emitting layers 52a, 52b, and 52c can be formed.

The drying process of the light emitting solution 56 is the same as the drying process of the hole injection solution 55, and when the drying is complete, the formation of the organic layer 50 including the light emitting layer 52 of uniform thickness is completed as shown in FIG. do.

Thereafter, the common electrode 61 is formed on the partition member 40 and the emission layer 52 that is the organic layer 50. When the common electrode 61 is deposited by depositing calcium and aluminum by the sputtering method, the display device 1 manufactured by the embodiment of FIG. 2 is completed.

According to the manufacturing method of the display apparatus according to the embodiment of the present invention, the manufacturing process may be easily formed by attaching the partition member rather than a complicated photo process to form the partition layer. As a result, manufacturing time and manufacturing cost of the display apparatus may be reduced, thereby increasing manufacturing efficiency.

The above embodiments can be variously modified. In the above embodiment, a case of using a high molecular material as the organic layer 50 is illustrated, but the present invention may be applied to a case of using a low molecular material as the organic layer 50. When using a low molecular weight material, the organic layer 50 may be formed by an evaporation method. In the above embodiment, a method of manufacturing a bottom emission display device is described, but the present invention is also applicable to a method of manufacturing a top emission display device.

Although some embodiments of the invention have been shown and described, it will be apparent to those skilled in the art that modifications may be made to the embodiment without departing from the spirit or spirit of the invention. . It is intended that the scope of the invention be defined by the claims appended hereto and their equivalents.

As described above, according to the present invention, there is provided a method of manufacturing a display device, in which a barrier layer can be easily formed and a manufacturing efficiency is high.

Claims (6)

Forming a thin film transistor on the insulating substrate; Forming a pixel electrode electrically connected to the thin film transistor; Attaching a partition member having an opening so that the opening corresponds to the pixel electrode; Forming an organic layer on the pixel electrode exposed by the opening; And forming a common electrode on the organic layer and the partition member. The method of claim 1, Between forming the thin film transistor and forming the pixel electrode, And forming a passivation layer on the thin film transistor. The method of claim 1, Between attaching the partition member and forming the organic layer, And an oxygen plasma treatment of the pixel electrode. The method of claim 1, The partition member is a manufacturing method of a display device comprising a polydimethylsiloxane (PDMS). The method of claim 1, And the organic layer comprises a hole injection layer and a light emitting layer sequentially formed. The method of claim 1, The organic layer is a method of manufacturing a display device, characterized in that formed by an inkjet method.

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