JP2002289349A - Manufacturing method of organic EL display device - Google Patents

Abstract

(57) [Summary] An object of the present invention is to provide a method of manufacturing an organic EL display device capable of improving the manufacturing yield and having good display quality. An anode electrode is formed in a display area on one main surface of a first substrate, and an organic electrode of each color is formed.
The partition 130 for partitioning the L element is formed, and a column 501 higher than the partition 130 is formed on the outer periphery of the display area.
A shadow mask M having an opening AP of a size corresponding to the organic EL element partitioned by 0 is arranged on the support 501, and the same opening AP of the shadow mask M is positioned at a different angle with respect to the first substrate 100. Color materials of different colors are deposited through the respective layers to form an organic light emitting layer in the organic EL element of each color.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic EL (electroluminescence) display device, and more particularly to a method of manufacturing an organic EL display device capable of improving a manufacturing yield.

[0002]

2. Description of the Related Art In recent years, an organic EL display device has attracted attention as a flat display device. Since this organic EL display device is a self-luminous element, it has a wide viewing angle, can be made thin without requiring a backlight, and has low power consumption.
In addition, it has a feature that the response speed is fast.

[0003] This organic EL display device is constituted by arranging, in a matrix, organic EL elements each having an organic light emitting layer containing an organic compound having a light emitting ability interposed between an anode electrode and a cathode electrode on one substrate. You. This organic EL element is very sensitive to moisture, and may be destroyed even by a small amount of moisture (about 1 ppm), so that the display performance as a display device may not be maintained.

[0004] Therefore, the step of laminating the organic light emitting layer in the organic EL element is generally performed by a vapor deposition process.

[0005] Usually, three colors of red (R), green (G) and blue (B) are used.
In the case of forming a color organic EL element, a shadow mask in which openings of substantially the same shape as the light emitting region of each pixel are arranged for one color is prepared. First, a pixel corresponding to red and an opening of this shadow mask are formed. Are aligned and fixed so that they do not shift, and a color material that emits red light is deposited.

Subsequently, using the same shadow mask,
A pixel corresponding to green and an opening of the shadow mask are aligned without breaking the vacuum, and both are fixed so as not to be displaced. Then, a color material that emits green light is deposited. Subsequently, using the same shadow mask, the pixel corresponding to blue and the opening of the shadow mask are aligned without breaking the vacuum, and fixed so that they do not shift. Evaporate.

[0007]

As described above, in the step of laminating the organic light emitting layers in the organic EL display device, it is necessary to align the shadow mask and the light emitting region of the pixel of each color with high precision for each color. . There is a problem that a manufacturing apparatus becomes expensive to perform high-precision alignment in a vacuum, and a time required for the alignment becomes long, thereby lowering a manufacturing yield.

[0008] Further, if the misalignment occurs for each color, the display characteristics differ for each color, causing a problem of deteriorating the display quality.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has as its object to improve the production yield and to provide an organic EL device having good display quality.
An object of the present invention is to provide a method for manufacturing a display device.

[0010]

According to a first aspect of the present invention, there is provided a method of manufacturing an organic EL display device, the method comprising:
In a method for manufacturing an organic EL display device in which organic EL elements of a plurality of colors with an organic light emitting layer sandwiched between an anode electrode and a cathode electrode, a partition partitioning the organic EL elements of each color is formed. A column higher than the partition is formed on the outer periphery, and a mask having an opening having a size corresponding to the organic EL element partitioned by the partition is arranged on the column, and the same mask is positioned at a different angle with respect to the substrate. Color materials of different colors are deposited through the openings to form organic light emitting layers in the organic EL elements of each color.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a method for manufacturing an organic EL display device according to the present invention will be described below with reference to the drawings.

As shown in FIG. 1, the organic EL display device comprises:
Two thin film transistors, TFTs 10 and 20
, An auxiliary capacitance element 30 and an organic EL element, that is, a light emitting section 40. The organic EL element 40 includes a TFT 10
, And the excitation power for the organic EL element 40 is controlled by the TFT 20.

[0013] Such an organic EL display device is an organic EL display device.
A plurality of scanning lines Y arranged along the row direction of the element 40
And a plurality of signal lines X arranged along the column direction of the organic EL element 40. The TFTs 10 and 20 are arranged near the intersection between the scanning line Y and the signal line X. T
The FT 20 is connected in series with the organic EL element 40. The auxiliary capacitance element 30 is connected in series with the TFT 10,
Further, it is connected in parallel with the TFT 20.

That is, the gate electrode of the TFT 10 is connected to the scanning line Y, the source region is connected to the signal line X, and the drain region is connected to one end of the auxiliary capacitance element 30 and the TF.
It is connected to the gate electrode of T20. The source region of the TFT 20 is connected to the power supply line P, and the drain region is connected to the anode electrode of the organic EL element 40. The other end of the auxiliary capacitance element 30 is connected to the power supply line P.

The TFT 10 supplies a driving signal of the corresponding signal line X to the TFT 20 and the auxiliary capacitance element 30 when selected via the corresponding scanning line Y, and controls the driving of the TFT 20. The TFT 20 supplies a drive current to the organic EL element 40 from the power supply line P based on the drive signal.

FIG. 2 is a cross-sectional view schematically showing the structure of an organic EL display device.
The structure of the L element, that is, the light emitting unit, is shown.

As shown in FIG. 2, the organic EL display device 1
Includes a first substrate 100 and a second substrate 200 which is arranged to face the first substrate at a predetermined interval. The first substrate 100 and the second substrate 200 are bonded together with a sealant 300, and the first substrate 100 and the second substrate 200 are bonded together.
A closed space 400 is formed between the substrate 200 and the substrate 200. The stacked body 40 constituting the organic EL element 40 includes a closed space 40
0.

The first substrate 100 is a transparent insulating substrate such as a glass substrate. The first substrate 100 is used to form a laminate that constitutes the organic EL element 40.
An FT 20, an anode electrode 104 in contact with a drain region of the TFT 20 via an insulating layer 102, an organic EL layer 110 disposed on the anode electrode 104, and a cathode sandwiching the organic EL layer 110 between the anode electrode 104 An electrode 112 and a cover metal 114 covering the cathode electrode 112 are provided. Organic EL element 4 for one pixel
0 is defined by partition walls 130 arranged in a lattice.

The TFT 20 has a semiconductor thin film of amorphous silicon or polysilicon. The anode electrode 104 is disposed on the transparent insulating film 102 and is formed of a transparent conductive member, for example, indium-tin-oxide (ITO).

The organic EL layer 110 includes a hole transport layer 106
And a light emitting layer 108. That is, the hole transport layer 106 is disposed on the anode electrode 104 and is formed of a thin film of an aromatic amine derivative, a polythiophene derivative, a polyaniline derivative, or the like. Light emitting layer 108
Are formed on the hole transport layer 106 and are formed of an organic compound that emits red (R), green (G), or blue (B) light. The light emitting layer 108 is made of, for example, Alq ₃
It has a laminated structure including a thin film formed by (aluminum quinolium complex), a PPV (polyparaphenylene vinylene), a polyfluorene derivative or a precursor thereof, and the like.

The cathode electrode 112 is formed of the organic EL layer 110
It is a reflective electrode formed of a material disposed thereon and performing the function of electron injection. The cathode electrode 112 is formed, for example, by depositing barium, calcium, barium-ytterbium, or the like. The organic EL layer 110 may include an electron transport layer between the light emitting layer 108 and the cathode electrode 112 in order to improve the efficiency of injecting electrons from the cathode electrode 112.

The cover metal 114 is formed on the cathode electrode 11.
2 and is formed by evaporating aluminum, for example.

In the organic EL device 40 having the above-described structure, electrons and holes are injected into the light emitting layer 108 sandwiched between the anode electrode 104 and the cathode electrode 114, and the electrons and holes are recombined to generate excitons. It is generated and emits light by light emission of a predetermined wavelength generated when the exciton is deactivated.

Next, a method of manufacturing the organic EL display device will be described.

That is, as shown in FIG. 3A, first, the formation and patterning of a metal film and an insulating film are repeated to form a thin film transistor, that is, a TFT 20 in the display area of the first substrate 100. At the same time, the first
Various electrode wirings are formed on the substrate 100, and 480 pixels vertically and 640 × 3 (R, G, B) pixels horizontally, and a total of about 92 pixels
An array substrate having 10,000 pixels is formed.

Subsequently, as shown in FIG.
By a method D, a transparent insulating film 102 is formed on the first substrate 100,
For example, a silicon oxide film is formed. Further, a contact hole 102a penetrating to the drain region of the TFT 20 is formed in the insulating film 102 by etching.

Subsequently, as shown in FIG. 3C, a transparent electrode member, for example, ITO is arranged corresponding to each pixel to form an anode electrode 104. This anode electrode 1
04 may be formed by depositing ITO over the entire surface of the substrate and then patterning it by a photoetching process, or may be formed by depositing ITO by a mask sputtering method corresponding to each pixel.

Subsequently, as shown in FIG. 3D, partition walls 130 are formed in a lattice shape so as to surround each pixel in order to prevent an electrical short between the pixels. This partition 130
After placing the UV curable acrylic resin resist,
It is formed by patterning by a photolithography process and further baking at 220 ° C. for 30 minutes.

Subsequently, as shown in FIG. 4A, an organic EL layer 110 is formed on the anode electrode 104 of each pixel. In this embodiment, first, a hole transport layer 106 is formed on the anode electrode 104. The hole transport layer 106 is formed by, for example, directly depositing a material such as an aromatic amine derivative on pixels for each color using a stripe-shaped shadow mask. Subsequently, the light-emitting layer 108 is stacked on the hole transport layer 106. The light-emitting layer 108 is formed by directly depositing the light-emitting layer 108 that emits each color of red, green, and blue on pixels of each color using the same shadow mask.

Subsequently, as shown in FIG. 4B, a cathode electrode 112 is formed on the organic EL layer 110, and subsequently, a cover metal 114 is formed on the cathode electrode 112. In this embodiment, first, in the vacuum chamber, the cathode electrode 112 is formed by depositing barium alone on the organic EL layer 110. Subsequently, a cover metal 114 is formed on the cathode electrode 112 by depositing aluminum alone or an alloy.

Subsequently, as shown in FIG. 4C, a UV-curable sealing material 300 is applied along the outer periphery of the second substrate 200 for sealing, and a nitrogen gas, an argon gas or the like is applied. In an inert gas atmosphere, the organic EL element 40
Is bonded to the first substrate 100 provided with. This allows
The organic EL element 40 is a closed space 40 in an inert gas atmosphere.
0. After that, the sealing material 300 is cured by irradiating ultraviolet rays.

The color display type active matrix organic EL display device thus formed has a thickness substantially equal to that of the first substrate and the second substrate.
The device life was excellent and the reliability was high.

The process for forming the organic EL layer 110 in the above-described method for manufacturing an organic EL display device will be described in more detail with reference to FIGS. That is, in this embodiment, the organic EL layer is formed by depositing color materials of different colors from different angles on the substrate using the same shadow mask.

First, as shown in FIG. 3D, columns 501 for supporting the shadow mask M are arranged on the outer periphery of the display area of the first substrate 100 on which the partition walls 130 have been formed by the photolithography process. The support 501 is formed by screen-printing a photosensitive polyimide resin. Note that the support column 501 may be formed by patterning the same material in the same step as the partition 130.

Subsequently, a shadow mask M having an opening AP having a size corresponding to the light emitting region of the organic EL element partitioned by the partition 130 is disposed on the support. At this time,
The shadow mask M is positioned and fixed so that the opening AP thereof corresponds to, for example, the light emitting region of the organic EL element for green color.

Subsequently, as shown in FIG. 5A, the opening AP of the shadow mask M is inclined by a first angle θ1 with respect to the normal O of the first substrate 100 by a vacuum evaporation apparatus. Through which a hole transport layer and an organic material emitting red light are continuously deposited. Thereby, the red pixel 60
The hole transport layer 106 and the red light emitting layer 108 are sequentially stacked in the light emitting region of 0R.

Subsequently, as shown in FIG. 5B, the hole transport layer and the green color are passed through the opening AP of the shadow mask M from the direction parallel to the normal line O of the first substrate 100 by a vacuum deposition apparatus. An organic material that emits light is continuously deposited. Thus, the hole transport layer 106 and the green light emitting layer 108 are sequentially stacked in the light emitting region of the green pixel 600G.

Subsequently, as shown in FIG. 5C, the opening AP of the shadow mask M is inclined from the direction inclined by the second angle θ2 with respect to the normal O of the first substrate 100 as shown in FIG. Through which a hole transport layer and an organic material that emits blue light are continuously deposited. Thereby, the blue pixel 60
The hole transport layer 106 and the blue light emitting layer 108 are sequentially stacked in the light emitting region of 0B.

That is, the red pixel 600R and the blue pixel 600B are respectively connected to the green pixel 60
It is arranged adjacent to 0G. Therefore, the green pixel 6
For 00G, a hole transport layer and a light emitting layer are stacked from a direction parallel to the normal O of the first substrate 100. For the red pixel 600R, the hole transport layer and the light emitting layer are stacked from a direction inclined by a first angle with respect to the normal O of the first substrate 100. Further, for the blue pixel 600B, the hole transport layer and the light emitting layer are stacked from a direction inclined by a second angle with respect to the normal O of the first substrate 100. The first angle θ1 and the second angle θ2 are symmetrical with respect to a predetermined reference line, that is, a normal line O of the substrate.

For example, the pitch of the anode electrode 104 corresponding to each color pixel is (P + K), the height of the partition 130 is H, the width of the bottom surface of the partition 130 is K, the height of the support 501 is (H + G), and the shadow mask The width of the opening AP of M is (P
+ 2Δ), θ1 = −tan ⁻¹ (G / (P + K)) θ2 = + tan ⁻¹ (G / (P + K)) In this embodiment, the height H of the partition 130 is 2 μm, the bottom width K of the partition 130 is 20 μm, and the pitch (P + K) of the anode electrodes 104 is 60 μm.
m, and the height (H + G) of the column 501 was 42 μm.

In a vacuum evaporation apparatus, when the positions of the evaporation sources of the hole transport layer and the light emitting layer are fixed, the red pixel 600
When the organic EL layer is deposited at R, the first substrate 100 provided with the shadow mask M is tilted by an angle of θ1 with respect to a horizontal plane parallel to the deposition source, and the organic E layer at the green pixel 600G is rotated.
At the time of deposition of the L layer, the first substrate 100 is parallel to a horizontal plane,
When the organic EL layer is deposited on the blue pixel 600B, the first
The substrate 100 is inclined by an angle θ2 with respect to the horizontal plane.

Thus, using the shadow mask M that has been aligned only once, through the same opening, the organic E of the color corresponding to each of the three color pixels arranged adjacent to each other.
L layers can be stacked.

The width (P + 2Δ) of the opening AP of the shadow mask M is approximately one pixel width when the first substrate 100 is inclined as shown in FIGS. 5A and 5C. When the first substrate 100 is arranged as shown in FIG. 5B, the width is set to be slightly wider than one pixel. This is to ensure that the organic EL layer is deposited on each color pixel. At this time, the organic EL layer deposited on the green pixel 600G is deposited not only on the light emitting region but also on the partition 130. However, since the partition 130 is formed to have a width to surely separate pixels of each color, The organic EL layer deposited on the partition 130 does not contribute to light emission. Therefore, the apparent area of the light emitting region can be the same for all the pixels of each color.

As described above, according to the method of manufacturing an organic EL display device of the present invention, the opening of the shadow mask and the light emitting area of the pixel of a predetermined color are aligned once, fixed, and then fixed. The organic EL layers of the respective colors are formed by depositing color materials of different colors from different positions through the openings of the same shadow mask.

For this reason, it is possible to shorten the time required for positioning the shadow mask as compared with the related art, and it is possible to improve the production yield. Also,
Since the organic EL layers of each color are formed by the above-described manufacturing method, it is possible to eliminate the problem that the displacement of the shadow mask does not occur for each color and the display characteristics are different for each color.

The present invention is not limited to the above-described embodiment, but can be variously modified without departing from the gist thereof.

[0047]

As described above, according to the present invention, it is possible to improve the manufacturing yield and to provide a method of manufacturing an organic EL display device having good display quality.

[Brief description of the drawings]

FIG. 1 is a circuit diagram schematically showing a configuration of an organic EL display device according to one embodiment of the present invention.

FIG. 2 is a sectional view schematically showing a structure of one pixel of the organic EL display device shown in FIG.

3 (a) to 3 (d) show the organic E of the present invention.
It is a figure for explaining the manufacturing method of an L display.

4 (a) to 4 (c) show the organic E of the present invention.
It is a figure for explaining the manufacturing method of an L display.

5 (a) to 5 (c) show the organic E of the present invention.
It is a figure for explaining a vapor deposition method of an organic EL layer in a manufacturing method of an L display.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Organic EL display device 10, 20 ... TFT 30 ... Auxiliary capacitance element 40 ... Organic EL element 100 ... 1st substrate 104 ... Anode electrode 110 ... Organic EL layer 112 ... Cathode electrode 114 ... Cover metal 200 ... 2nd substrate 300 ... Sealing material 501: Support column 600 (R, G, B): Pixel M: Shadow mask AP: Opening O: Substrate normal

Claims (6)

[Claims] In a display area on one main surface of a substrate,
In a method of manufacturing an organic EL display device in which an organic EL element of a plurality of colors having an organic light emitting layer sandwiched between an anode electrode and a cathode electrode, a partition partitioning the organic EL elements of each color is formed, A column having a height higher than that of the partition wall is formed on the outer periphery, and a mask having an opening having a size corresponding to the organic EL element partitioned by the partition wall is arranged on the column. Wherein different color materials are deposited through the openings to form organic light emitting layers in the organic EL elements of each color. 2. The mask according to claim 1, wherein the opening is positioned so as to correspond to the organic EL element of the first color, and the color material of the first color is arranged in a direction parallel to a normal line of the substrate. 2. The method according to claim 1, wherein the deposition is performed through an opening of the mask. 3. A color material of a second color is deposited through an opening of the mask from a direction inclined by a first angle with respect to a normal of the substrate, and a color material of a third color is deposited on the substrate. Second to normal
And depositing through the opening of the mask from a direction inclined by an angle of (a), wherein the first angle and the second angle are angles symmetric with respect to a normal line of the substrate. 3. The method for manufacturing an organic EL display device according to 1 or 2. 4. The mask is arranged so that an opening thereof corresponds to an organic EL element of a first color. The height of the partition wall is H and the width of a bottom surface is K. The pitch of the organic EL element is (P + K), the height of the support is (H + G), and the width of the opening of the mask is (P + 2).
Δ), the color material of the first color is deposited through the opening of the mask from a direction parallel to the normal line of the substrate, and the color material of the second color is θ with respect to the normal line of the substrate. = -Tan
⁻¹ (G / (P + K)), deposited through the same opening of the mask from a direction inclined by (G / (P + K)), and a third color material is θ = + tan with respect to the normal to the substrate.
^{2. The} method according to claim 1, wherein the deposition is performed through the same opening of the mask from a direction inclined by ⁻¹ (G / (P + K)). 3. 5. The organic EL element of the second color and the organic EL element of the third color.
5. The method according to claim 3, wherein the organic EL elements of the first color are arranged adjacent to the organic EL elements of the first color with the partition walls interposed therebetween. 6. . 6. The method for manufacturing an organic EL display device according to claim 1, wherein the color materials of the respective colors are deposited by vapor deposition.