JP4364957B2 - Evaporation mask - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vapor deposition mask used for manufacturing an EL element used for light emission display of a flat light source, a display, and other predetermined patterns.
[0002]
[Prior art]
Conventionally, in an organic EL (electroluminescence) element, a transparent ITO film is formed on one surface of a transparent substrate made of glass or the like, and a transparent electrode is formed in a predetermined stripe shape by mask vapor deposition or etching. The transparent electrode is formed to a thickness of, for example, 500 to 3000 mm, and a light emitting layer is formed on the transparent electrode. In the light emitting layer, the organic EL material is usually formed in a thickness of about 500 to 1500 mm over 2 to 3 layers, and a back electrode is formed on the surface of the light emitting layer by vapor deposition or the like.
[0003]
Here, the organic EL material constituting the light emitting layer is composed of a hole transport material such as a triphenylamine derivative (TPD) and an electron transport material such as an aluminum chelate complex (Alq ₃ ) which is a light emitting material. The light emitting layer is formed by stacking an electron transport material on a hole transport material or a mixed layer thereof. The back electrode material is made of a metal such as Al, Li, Ag, Mg, In, or an alloy thereof.
[0004]
The light emitting portion formed in this way is driven by a so-called dot matrix method in which a predetermined current is passed through a predetermined intersection between the transparent electrode and the back electrode so that the light emitting layer emits light.
[0005]
[Problems to be solved by the invention]
In the case of the above prior art, in the case of forming an ITO transparent electrode by etching, a process such as cleaning or a work in a clean room is required, and waste liquid treatment after cleaning is also a problem. Further, the etched surface is not sufficiently smooth as compared with the thickness of the light emitting layer, and causes a short circuit between the electrodes.
[0006]
Also, when the transparent electrode is formed by mask vapor deposition, if the mask becomes large, the central portion of the stripe will sag, and the edge portion of the striped transparent electrode formed by masking will not be deposited accurately and neatly. I could be out of focus. In addition, it is possible to suck this mask with a magnet, but it is difficult to suck the mask uniformly with a magnet, and the position of the putter itself is shifted, which hinders accurate pattern formation during deposition. Met.
[0007]
The present invention has been made in view of the above problems of the prior art, and an object of the present invention is to provide a vapor deposition mask capable of accurately forming a thin film such as a transparent electrode with a simple configuration.
[0008]
[Means for Solving the Problems]
In order to form a thin film having a predetermined shape on the surface of a transparent substrate such as glass or resin, the present invention provides an annular frame formed of a shape memory alloy in a vapor deposition mask that covers the substrate surface, A mask configuration in which an opening is formed on the inner side and shape-memorized in a curved shape bulging in an arc toward the vapor deposition surface side of the substrate when disposed between the substrate and the vapor deposition source And a reinforcing member for reinforcement that is attached to the surface of the portion other than the opening of the mask component and prevents sagging of the mask, and heats the mask component by energizing the reinforcement. An evaporation mask that restores the memorized shape of the mask component and allows the mask component to adhere to the substrate during vapor deposition.
It is a vapor deposition mask.
[0009]
In addition, the present invention forms a transparent electrode on a transparent substrate surface such as glass or resin with a transparent electrode material so as to form a stripe shape at a predetermined pitch, and forms a light emitting layer made of an EL material on the transparent electrode by forming a vacuum thin film. In a vapor deposition mask used for manufacturing an EL device in which a back electrode having a predetermined pitch is formed in a stripe shape in a direction opposite to the transparent electrode and orthogonal to the surface of the light emitting layer, the layer is formed by a shape memory alloy. An annular frame and a striped opening for forming the electrode inside the frame are formed, and when disposed between the substrate and the deposition source, the deposition surface side of the substrate Is attached to the surface of the portion of the mask constituent portion sandwiched between the opening portion of the mask constituent portion, and the shape of the mask constituent portion that is bulged and curved in an arc shape toward A reinforcing body for reinforcement that prevents sagging of the mask, the mask component is heated by energizing the reinforcement, the memory shape of the mask component is restored, and the mask component during vapor deposition Is a vapor deposition mask that can adhere to the substrate. The reinforcing body is a wire, and the shape of the memory is restored by energizing the wire to heat the shape memory alloy mask. The reinforcing body is a vapor deposition mask that is formed of a shape memory alloy, heats the reinforcing body of the shape memory alloy, restores the memory shape of the mask constituent portion, and adheres the mask constituent member to the substrate during vapor deposition. .
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 2, the organic EL element 10 formed using the vapor deposition mask of this embodiment is made of a transparent electrode material such as ITO on one surface of a transparent substrate 12 such as glass, quartz, or resin. A transparent electrode 14 is formed. The transparent electrode 14 is formed on the substrate 12 in a stripe shape at a predetermined pitch. On the surface of the transparent electrode 14, a light emitting layer 16 made of an EL material made of a hole transport material of about 500 mm, an electron transport material of about 500 mm, and other light emitting materials is laminated. On the surface of the light emitting layer 16, a back electrode 18 made of a cathode material such as an Al—Li alloy containing about 0.01 to 0.05% of Li and having a purity of about 99%, and other Al—Mg is appropriately 500 to 1000 mm. It is laminated with a thickness of about.
[0011]
The back electrode 18 faces the transparent electrode 14 at right angles and is formed in a stripe shape. The transparent electrode 14 to the back electrode 18 stacked on the substrate 12 form a light emitting portion.
[0012]
Here, the light emitting layer 18 includes a triphenylamine derivative (TPD), a hydrazone derivative, an arylamine derivative and the like as a hole transport material among the mother material. On the other hand, as the electron transporting material, an aluminum chelate complex (Alq ₃ ), a distyrylbiphenyl derivative (DPVBi), an oxadiazole derivative, a bistyrylanthracene derivative, a benzoxazole thiophene derivative, a perylene, a thiazole, or the like is used. Further, an appropriate light emitting material may be mixed, and a light emitting layer in which a hole transport material and an electron transport material are mixed may be formed. In that case, the ratio of the hole transport material to the electron transport material is 10:90 to 90. : It can change suitably in the range of 10.
[0013]
As shown in FIG. 1A, the vapor deposition mask 22 for manufacturing the organic EL element has openings 20 formed in a stripe shape in, for example, a rectangular annular frame 24, and narrow portions between the openings 20. The reinforcing body 26 made of a linear material is attached in a tensioned state.
[0014]
The reinforcing body 26 is a conductive wire, a polyimide aramid fiber, or the like. For example, when the light emitting dots of about 4 mm square are formed at regular intervals at a pitch of about 5 mm on the substrate 12 of 30 cm, the reinforcing body 26 has, for example, a reinforcing body of about 0.5 mm in the mask portion between the openings 20. 26 is arranged. At this time, as shown in FIG. 3, the reinforcing member 26 is attached to the frame 24 in a state of being slightly curved in an arc shape toward the substrate 12 side.
[0015]
The vapor deposition mask 22 is brought into contact with the surface of the transparent substrate 12, and a transparent electrode material such as ITO is provided by vapor deposition or the like. At this time, as shown in FIG. 4, the vapor deposition mask 22 is brought into close contact with the substrate 12 against the curve, the vapor deposition mask 22 is superimposed on the transparent substrate 12, and the vapor deposition mask 22 is deposited on the substrate 12. It is located on the 34th side and is vacuum-deposited. Then, after vapor deposition, the vapor deposition mask 22 is removed from the substrate 12. Thereby, the transparent electrode 14 by the opening 20 is formed accurately.
[0016]
Next, on the surface of the transparent electrode 14, for example, a hole transport layer made of a hole transport material such as TPD as an organic EL material, an electron transport layer made of an electron transport material such as Alq _3, or a layer made of another light emitting material, The light emitting layer 16 is formed by stacking by sputtering or other vacuum thin film forming technology.
[0017]
When the light emitting layer 16 is deposited, vacuum deposition is performed using a light emitting layer mask 30 having an opening 28 having the size of the light emitting layer 16 as shown in FIG. As the deposition conditions, for example, the degree of vacuum is 6 × 10 ⁻⁵ Torr, and in the case of an EL material, the film is formed at a deposition rate of 50 Å / sec. The light emitting layer 14 and the like may be formed by flash vapor deposition. In the flash vapor deposition method, an EL material mixed in advance at a predetermined ratio is dropped onto a vapor deposition source heated to 300 ° C. to 600 ° C., preferably 400 ° C. to 500 ° C., and the EL material is evaporated at once. Further, the EL material may be accommodated in a container, and the container may be rapidly heated and vapor-deposited at once.
[0018]
Next, a back electrode material made of an Al—Li alloy containing about 0.01% to 0.05% of Li and having a purity of about 99%, and other cathode material of Al—Mg is vacuum-deposited on the surface of the light emitting layer 16. Provided by thin film formation technology. Also at this time, as shown in FIG. 1C, the back electrode 18 is formed in a direction orthogonal to the transparent electrode 14 by using the vapor deposition mask 32 similar to that in FIG. The back electrode 18 is laminated with a thickness of about 500 to 1000 mm.
[0019]
Further, an insulating protective film such as SiO (not shown) may be formed on the entire surface of the light emitting layer and the back electrode by vacuum deposition, sputtering, or other vacuum thin film forming techniques. Further, a water repellent film, a resin protective film, or the like may be provided.
[0020]
According to the vapor deposition mask for manufacturing the EL element of this embodiment, even when forming a large EL element, an EL element having an accurate pattern can be easily formed by a thin film forming technique such as vacuum vapor deposition, not by etching. Can be formed. In particular, since the mask 22 is reinforced and curved toward the substrate side, when it is pressed against the substrate 12, it comes into close contact with the entire surface of the substrate 12, and the central portion of the mask sags to create a gap with respect to the substrate surface. In this way, an electrode with an accurate pattern is formed.
[0021]
Furthermore, the vapor deposition mask of the present invention is such that the frame 24 is made of a shape memory alloy and the shape shown in FIG. As a result, first, the flat mask 22 is brought into contact with the substrate 12 and then the mask 22 is heated. As a result, the frame 24 tends to bend as shown in FIG. 3, and the mask 22 comes into close contact with the surface of the substrate 12. .
[0022]
Further, as a heating means for the mask 22 made of shape memory alloy, the reinforcing body 26 is a wire, and the mask 22 is heated by energization to perform the shape memory operation. Further, the reinforcing body 26 itself has a shape curved toward the substrate 12, and as a shape memory alloy having this shape as a memory shape, as shown in FIG. By disposing the reinforcing body 26 so as to bend toward the substrate 12 by heating, the central portion of the mask 22 always tends to bend toward the substrate 12 at the time of vapor deposition so that a gap is formed between the substrate 12 and the mask 22. There is no.
[0023]
In addition, it is necessary to heat in the shape memory operation. At this time, in order not to heat the substrate 12 more than necessary, for example, a shape memory alloy frame may be heated with a wire that can be energized. Thereby, the heating to the substrate side is suppressed and the frame portion is reliably heated.
[0024]
【The invention's effect】
According to the vapor deposition mask of the present invention, mask vapor deposition can be performed accurately even in an EL element having a large display area, the cost is low, and the EL element greatly contributes to a large screen.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a process for using a vapor deposition mask according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view showing one embodiment of a deposition mask according to the present invention.
FIG. 3 is a front view showing a usage state of the vapor deposition mask of the present invention.
FIG. 4 is a front view showing a usage state of the vapor deposition mask of the present invention.
[Explanation of symbols]
12 Substrate 14 Transparent electrode 16 Light emitting layer 18 Back electrode 20 Opening 26 Reinforcing body

Claims (4)

In order to form a thin film of a predetermined shape on the substrate surface, in the vapor deposition mask covering the substrate surface,
An annular frame formed of a shape memory alloy;
An opening is formed on the inner side of the frame, and when it is disposed between the substrate and the vapor deposition source, the shape is memorized in a curved shape that bulges in an arc shape toward the vapor deposition surface side of the substrate. Mask components,
It is attached to the surface of a portion other than the opening of the mask component , and includes a reinforcing body for reinforcement that prevents sagging of the mask ,
A vapor deposition mask, wherein the mask component is heated by energizing the reinforcing body to restore the memory shape of the mask component, so that the mask component can adhere to the substrate during vapor deposition. A transparent electrode is formed on a transparent substrate surface in a stripe shape with a transparent electrode material at a predetermined pitch, and a light emitting layer made of an EL material is laminated on the transparent electrode by a vacuum thin film forming technique. In addition, in a vapor deposition mask used for manufacturing an EL element in which a back electrode having a predetermined pitch is formed in a stripe shape in a direction orthogonal to the transparent electrode,
An annular frame formed of a shape memory alloy;
A stripe-shaped opening for forming the electrode is formed inside the frame, and when arranged between the substrate and a deposition source, an arc shape toward the deposition surface side of the substrate. A mask component that is shape-memoryd into a curved shape
A reinforcing member attached to the surface of the portion sandwiched between the openings of the mask component and for preventing sagging of the mask; and
A vapor deposition mask, wherein the mask component is heated by energizing the reinforcing body to restore the memory shape of the mask component, so that the mask component can adhere to the substrate during vapor deposition.   3. The vapor deposition mask according to claim 1, wherein the reinforcing body is a wire, and the shape of the shape memory alloy is heated by energizing the wire to restore the memory shape. The said reinforcement body is formed with a shape memory alloy, the said reinforcement body of the said shape memory alloy is heated, the said memory shape of the said mask component is returned, and the said mask component is contact | adhered to the said board | substrate at the time of vapor deposition. Vapor deposition mask.

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