JP2003163075A - Organic el element and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic EL element structure together with its manufacturing method which is of high precision and brightness. <P>SOLUTION: An organic EL element comprises a diffraction lattice which sandwiching an organic thin-film layer of single ply or a plurality of plies between an anode 30 and a cathode 50. The area of diffraction lattice disposed to each light-emitting pixel is larger than the area of the light-emitting pixel. The manufacturing process of the EL element includes a process in which a photomask which decides position and size of the diffraction lattice in a substrate is installed at a position on the surface of photosensitive material where no laser non-interference exposure part is formed, a process where the photosensitive material is exposed by a two-beam laser interference exposure system, and a process where the substrate or the thin film formed on the substrate is etched to provide a diffraction lattice. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic EL element which is an optical element which is used in a display device such as a display and which emits light in a specific wavelength region by current driving, and a method for manufacturing the same.

[0002]

2. Description of the Related Art Organic electroluminescence (EL)
The device is a self-luminous device utilizing the principle that a fluorescent substance emits light by recombination energy of holes injected from an anode and electrons injected from a cathode when an electric field is applied. C. W. Tang et al. Reported a low-voltage driven organic EL device using a stacked device (CW Tang, S. et al.
A. VanSlyke, Applied Physics Letters
s), vol. 51, p. 913, 1987), and so on, researches on organic EL devices using organic materials as constituent materials have been actively conducted.

Tang et al. Use tris (8-quinolinol) aluminum for the light emitting layer and a triphenyldiamine derivative for the hole transporting layer. The advantages of the laminated structure are that the injection efficiency of holes into the light emitting layer is increased, the generation efficiency of excitons generated by recombination by blocking electrons injected from the cathode is increased, and that generated inside the light emitting layer. Examples include confining excitons. As the element structure of the organic EL element as in this example, hole transport (injection) is performed.
Layer, two-layer type of electron-transporting light-emitting layer, or hole transport (injection)
A three-layer type including a layer, a light emitting layer, and an electron transporting (injecting) layer is well known. In such a laminated structure element, in order to enhance the recombination efficiency of injected holes and electrons, the element structure and the forming method have been devised.

However, in the organic EL element, the probability of singlet generation is limited due to the dependence of spin statistics upon carrier recombination, and therefore, the emission probability has an upper limit. It is known that the upper limit value is about 25%. Further, in a surface emitting element such as an organic EL element, light having an emission angle larger than the critical angle undergoes total reflection and cannot be extracted to the outside due to the influence of the refractive index of the light emitting body. Therefore, if the refractive index of the light emitter is 1.6, it is estimated that only about 20% of the total amount of emitted light can be effectively used. For this reason, as a limit of the energy conversion efficiency, the efficiency is inevitably about 5% as a whole, including the singlet generation probability (Tetsuo Tsutsui, "Current Status and Trends of Organic Electroluminescence", Monthly Display, vol.1). , No. 3, p11, 19
(September 1995). In the organic EL element in which the light emission probability is strongly limited, the light extraction efficiency causes a fatal decrease in efficiency.

As a method for improving the light extraction efficiency, a light emitting element having an equivalent structure such as an inorganic electroluminescence element has been conventionally studied. For example, a method of improving efficiency by providing a substrate with a light-converging property (Japanese Patent Laid-Open No. 63-314795) or a method of forming a reflecting surface on the side surface of an element (Japanese Patent Laid-Open No. 1-2203
94) has been proposed.

However, these methods are effective for devices having a large light emitting area, but for devices having a small pixel area such as a dot matrix display,
It is difficult to form a lens having a light-collecting property and a side reflection surface. Further, in the organic EL element, since the thickness of the light emitting layer is several μm or less, it is difficult to form a reflecting mirror on the side surface of the element by taper processing, and it is difficult with the current microfabrication technology, resulting in a significant cost increase. Bring

There is also a method of forming an antireflection film by introducing a flat layer having an intermediate refractive index between the substrate glass and the light emitter (Japanese Patent Laid-Open No. 62-172691). Although it has the effect of improving the extraction efficiency, it cannot prevent total internal reflection. Therefore, even if it is effective for inorganic electroluminescence having a large refractive index, it is not possible to obtain a great improvement effect for an organic EL element which is a light emitting body having a relatively low refractive index.

Therefore, the light extraction method useful for the organic EL element is still insufficient, and the development of this light extraction method is indispensable for improving the efficiency of the organic EL element. Therefore, in order to improve the light extraction efficiency, an organic EL element having a diffraction grating as a constituent element is disclosed in JP-A-11-283751.
It is disclosed in the publication. By this method, the light extraction efficiency of the organic EL element is improved, and the light emission efficiency of the element is improved. In this case, it is desirable that the diffraction grating has a pitch that is as fine as visible light, but using a method such as photolithography to form the diffraction grating causes technical difficulties, and these methods are Being expensive. Therefore, a method for forming a diffraction grating with a fine pitch more easily is desired. Two-beam laser interference exposure utilizes interference fringes generated when coherent two-beam laser beams are made to interfere with each other, and is an effective method for forming an ultrafine periodic pattern on the order of light wavelength (Hiro Nishihara Integrated circuit "Ohmsha, P224-228).

On the other hand, an organic E having each display pixel of RGB
In the L element, it is necessary to dispose diffraction gratings with different pitches (grating intervals) in each pixel, but in order to manufacture this pixel pattern, conventionally, two-beam laser interference exposure is repeatedly performed on a substrate to which a photomask is adhered. I was going.

[0010]

In the conventional method of performing two-beam laser interference exposure in the state where the photomask is in close contact with the substrate, the non-interference exposure portion due to the thickness of the photomask is formed on the photosensitive material. Therefore, there is a problem that a fine pattern cannot be formed. In particular, the area of the non-interference exposure area increases as the size of each pixel of RGB decreases, and as a result, the area of the diffraction grating decreases, so that the light extraction efficiency of the high-resolution organic EL element remarkably decreases. As described above, it has been difficult to achieve both improvement of light extraction efficiency and high resolution of pixels. Furthermore, conventionally,
In order to manufacture three types of diffraction gratings having different pitches according to RGB, it is necessary to change the photomask and repeatedly perform the two-beam interference exposure, which causes a problem of low manufacturing efficiency.

It is an object of the present invention to provide a high light extraction efficiency in an organic EL device having a fine pixel pattern, and to provide a manufacturing method for reducing the non-interference exposure portion in two-beam laser interference exposure. . Furthermore, by simultaneously producing three types of diffraction gratings having different pitches according to RGB, an organic E including a diffraction grating is produced.
An object of the present invention is to provide a manufacturing method for significantly improving the manufacturing efficiency of L elements.

[0012]

Means for Solving the Problems As a result of intensive studies by the present inventors, the light extraction efficiency is increased by increasing the area of the diffraction grating arranged in each light emitting pixel of the organic EL element to be larger than the pixel electrode area. It was newly discovered that an organic EL device with high brightness can be obtained, and in particular, this effect becomes more remarkable as the pixel size becomes smaller. Further, such a diffraction grating can be efficiently manufactured by arranging it in a position where the photomask is not brought into close contact with the substrate in the two-beam laser interference exposure and the laser non-interference exposure part is not formed on the surface of the photosensitive material. Found. According to this manufacturing method, it is possible to eliminate the non-interference exposure portion due to the thickness of the mask and the incident angle of the laser light, and it is possible to suppress the reduction in the area of the diffraction grating. Further, according to this method, it is possible to simultaneously manufacture three types of diffraction gratings having different pitches according to the respective RGB pixels, and it is possible to significantly improve the manufacturing efficiency of the full-color organic EL element including the diffraction grating. it can.

That is, according to the present invention, as shown in FIG.
In an organic EL device including a diffraction grating, one or a plurality of organic thin film layers sandwiched between an anode and a cathode,
An organic EL element characterized in that the area of the diffraction grating arranged in each light emitting pixel is larger than the area of the light emitting pixel, and more specifically, the area of the light emitting pixel is 2 mm ² / pixel or less. . Further, there are three types of light emitting pixels of RGB, and more specifically, it is characterized in that the periods of the diffraction gratings adjacent to the light emitting pixels of RGB are different from each other, and the period of the diffraction grating is 100 nm to 600 nm.
It is characterized by being.

More specifically, the invention according to claim 1 is an organic EL element comprising a diffraction grating, which comprises one or a plurality of organic thin film layers sandwiched between an anode and a cathode, and the diffraction grating Is larger than the area of the light emitting pixel.

The invention described in claim 2 is the same as claim 1.
In addition to the described structure, the area of the light emitting pixel is 2 mm ² / pixel or less.

Further, in the invention described in claim 3, in addition to the configuration according to claim 1 or 2, the light emitting pixel is R (red),
It is characterized by three types of G (green) and B (blue).

The invention according to claim 4 is the same as claim 3
In addition to the described configuration, the diffraction gratings adjacent to the light emitting pixels made of RGB have different periods.

Further, the invention according to claim 5 is characterized in that, in addition to the structure according to any one of claims 1 to 4, the period of the diffraction grating is 100 nm to 600 nm.

The invention according to claim 6 is a method for manufacturing an organic EL device comprising a single or a plurality of organic thin film layers sandwiched between an anode and a cathode, and including a diffraction grating. A step of placing a photomask that determines the position and size of the diffraction grating at a position on the surface of the photosensitive material that does not form a laser non-interference exposure portion, and a step of exposing the photosensitive material by a two-beam laser interference exposure system, A step of forming a diffraction grating by etching the substrate or a thin film formed on the substrate.

Furthermore, the invention according to claim 7 is characterized in that, in addition to the structure according to claim 6, at least one photomask is installed on the one-beam optical path before the laser beam splitting. .

The invention described in claim 8 is the same as claim 6.
In addition to the described structure, at least one photomask is installed in each optical path on the two-beam optical path after the laser light is split.

Further, the invention according to claim 9 is characterized in that, in addition to the structure according to any one of claims 6 to 8, a plurality of two-beam laser interference exposure systems having the photomask are provided. To do.

The invention described in claim 10 is characterized in that, in addition to the configuration described in claim 9, the plurality of two-beam laser interference exposure systems are incoherent to each other.

Further, in the invention described in claim 11, in addition to the structure described in any one of claims 6 to 10, the cross angle of the two-beam laser interference exposure system is 150 degrees or less, and the substrate The two-beam laser interference exposure is performed from the same plane direction.

In addition to the structure according to any one of claims 8 to 11, the invention according to claim 12 is the wavelength or crossing angle of a laser used in the plurality of two-beam laser interference exposure systems. Are different.

Further, in the invention described in claim 13, in addition to the structure described in any one of claims 9 to 12, there are three types of the two-beam laser interference exposure system, and each exposure is performed sequentially or simultaneously. It is characterized by

Further, in the invention described in claim 14, in addition to the structure according to any one of claims 6 to 13, in the step of exposing the photosensitive resin by the two-beam laser interference exposure system, Exposure is performed from the side of the substrate coated with the resin, and a light absorbing plate is provided on the other substrate surface.

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a cross section of an organic EL device having a diffraction grating of the present invention. In the organic EL device, the high refractive index layer 20, the anode 30, the
Elements are provided in the order of the organic layer 40 and the cathode 50. Further, the arrow from the substrate 10 indicates the light emission 60.

In the present invention, the photosensitive material coated on the substrate is exposed to the interference light using a laser to expose the photosensitive material. However, a photo that determines the position and size of the diffraction grating in the substrate is used. The mask is placed on the surface of the photosensitive material at a position where it does not form a laser non-interference exposure portion.

FIG. 2 shows an example of the laser light source 7
A photomask 90 having a pixel pattern is arranged on the optical path of the laser light emitted from the laser beam 0 through the beam expander 80. The laser light flux 110 that has passed through the photomask 90 is split into two laser light fluxes by the beam splitter 100. This is the mirror 120, 12
When an appropriate angle is set by 1 and they are crossed on the substrate, a standing wave is formed by interference. The light intensity is maximum at the belly and zero at the node. Therefore, when a laser beam is incident on the photosensitive material 130 applied on the substrate 11 under such a condition that a standing wave is formed, the photosensitive material is exposed in accordance with the light intensity, so that the highly sensitive portion is exposed. And the weak portion form a periodic structure in a direction parallel to the thin film surface.

Here, if the conditions of the laser light are set appropriately, a difference in solubility in the developing solution occurs between the strongly sensitive part and the weakly sensitive part due to the photochemical reaction of the photosensitive material. A fine pattern having a periodic structure, that is, a diffraction grating is formed. Photo mask 9
0 is set at a position on the surface of the photosensitive material 130 on the laser optical path where the laser non-interference exposure portion is not formed, so the non-interference exposure portion due to the thickness of the photomask 90 and the laser incident angle is photosensitive. Not present on material surface.
In the case of the configuration shown in FIG. 2, the period of the standing wave, that is, the pitch d of the diffraction grating formed by using this method, the wavelength of the laser is λ, and the photosensitive material 130 on the substrate 11 is irradiated with 2
If the crossing angle of the light beam laser is θ (laser crossing angle 140), then d 2 = λ / 2 / sin (θ / 2).

As θ increases, d decreases, and when the crossing angle is 180 °, d becomes λ / 2, which is the minimum value. For example, when irradiating a laser beam of λ = 488 nm with an argon ion laser, d> 244 nm. That is,
The pitch can be easily set to any value larger than 244 nm simply by adjusting the crossing angle. The photomask 90 has only to be installed at a position on the surface of the photosensitive material 130 on the laser beam path where the laser non-interference exposure portion is not formed, and may be installed on the one-beam optical path before the laser beam splitting. Alternatively, they may be installed in respective optical paths on the two-beam optical path after the laser light branch. At this time, the number of photomasks 90 need not be one on each light flux, and may be two or more.

FIG. 3 is a sectional view of the substrate 12 when the conventional photomask 91 is brought into close contact with the photosensitive material and interference exposure is performed using the laser beams 111 and 112. The thickness of the photomask 91 is shown in FIG. It can be seen that the non-interference exposure parts 150 and 151 caused by the laser incident angle are generated at both ends of the interference exposure part 160. When the RGB pixels are separated from each other, the photosensitive material 131 due to the non-interference exposure is generated.
However, if the pixels are close to each other, the non-interference exposure units 150 and 151 overlap the adjacent pixels, and the diffraction grating of the adjacent pixels is destroyed.

The number of the two-beam laser interference exposure system having the photomask in the present invention is not necessarily one, and a plurality of two-beam laser interference exposure systems can be used.

In FIG. 4, three kinds of two-beam laser interference exposure systems are used, and three kinds of diffraction gratings corresponding to RGB are arranged on the same plane. On the substrate 13, a high refractive index layer 21,
22 and 23 are provided, each of which has a high refractive index layer 2
Anodes 31, 32, 33, organic layer 4 on 1, 22, 23
1, 42, 43, and cathodes 51, 52, 53 are provided in this order. Light emission 61, 62, 63 is emitted in the arrow direction from the three types of diffraction gratings arranged on the same plane. In order to arrange the three types of diffraction gratings corresponding to RGB on the same plane as shown in FIG. 4, it is possible to install the three types of two-beam laser interference exposure system shown in FIG.

FIG. 5 is a schematic view showing a case where three types of two-beam laser interference exposure systems are arranged. In FIG. 5, one laser light source 71, 72, 73 divides the optical path. When exposure is performed using a plurality of two-beam laser interference exposure systems in this way, exposure may be performed sequentially or simultaneously.

In order to expose the photosensitive material 132 with the three two-beam laser interference exposure system, the three two-beam laser interference exposure system has the following configuration. The three laser light sources 71, 72, 73 are incoherent to each other. Beam expanders 81, 82, and 83 are arranged next to the laser light sources 71, 72, and 73. further,
Photomasks 92, 93 and 94 for forming pixels are provided next to the beam expanders 81, 82 and 83. And three two-beam laser interference exposure system,
Beam splitter 101, 102, 103 for laser light
And divide it into two mirrors 122, 123, 124, 12
Substrate 14 with an appropriate angle set by 5, 126, 127
Each of the above intersects at a predetermined intersection angle θ.

In the method of manufacturing an organic EL device of the present invention, it is desirable that the crossing angle of the two-beam laser interference exposure system is 150 degrees or less and that the two-beam laser interference exposure is performed from the same plane direction of the substrate. The pitch of the diffraction grating of the present invention can be arbitrarily set according to the emission spectrum of the organic EL element, but is preferably about 100 nm to 600 nm. Further, the line to space ratio of the diffraction grating does not necessarily have to be 1: 1. Further, the diffraction grating is not necessarily limited to one dimension, and may be two dimension.

As the laser used in the present invention, known lasers can be appropriately used as long as laser light of a required wavelength can be obtained. For example, solid-state lasers, gas lasers, semiconductor lasers, dye lasers, and the like. When used for forming a diffraction grating included in an organic EL device, it is preferable that the wavelength is about the same as visible light. For example, YAG laser, YAG laser overtone, YAG laser overtone, dye laser, He-Ne laser, Ar
Ion lasers, Kr ion lasers, Cu vapor lasers, He-Cd lasers, N ₂ lasers and the like can be mentioned.

The photosensitive material used in the present invention can be appropriately selected from a positive type resist material, a negative type resist material and the like. In the present invention, when a diffraction grating is formed of a photosensitive material and a substrate or a thin film formed on the substrate is etched using this diffraction grating, the etching can be appropriately selected from known methods. For example, wet etching, reactive gas etching, ion milling, etc. may be mentioned. After the etching, the organic EL layer can be directly formed on the substrate including the diffraction grating from which the photosensitive material has been removed by the remover, or the organic EL layer can be formed after forming another thin film. Absent. The thin film may be a transparent and high refractive index material such as TiO ₂ or SiN _x . The thickness of this high refractive index layer is preferably 100Å to 20000Å.

Each of the R, G, and B light emitting pixel sizes, their shapes, and pixel intervals in the organic EL device of the present invention can be arbitrarily selected. However, in order to improve the light extraction efficiency by increasing the area of the diffraction grating, each light emitting device can be used. Pixel area is 2mm
It is desirable that the number is ² / pixel or less. At this time, the area of the diffraction grating is preferably at least 101% or more of the area of the light emitting pixel. The shape of the diffraction grating does not necessarily have to be similar to the shape of the light emitting pixel, but it is desirable that the light emitting pixel is within the area of the diffraction grating when viewed from the substrate normal direction. It should be noted that each of the RGB light emitting pixels need not have the same area, shape, or the like.

The element structure of the organic EL element according to the present invention is
It has a structure in which one or more organic layers are laminated between electrodes, and examples thereof include a structure composed of an anode / a light emitting layer / a cathode and a structure composed of an anode / a hole transporting layer / a light emitting layer / an electron transporting layer / a cathode. , A structure composed of anode / hole transport layer / light emitting layer / cathode, a structure composed of anode / light emitting layer / electron transport layer / cathode, and the like.

The hole-transporting material used in the present invention is not particularly limited, and any compound commonly used as a hole-transporting material may be used. Specific examples of the hole transport material include, for example, the following bis (di (p-tolyl) aminophenyl) -1,1-cyclohexane, N, N′-diphenyl-N, N′-bis (3-methylphenyl). -1,
1'-biphenyl-4,4'-diamine, N, N'-diphenyl-N, N'-bis (1-naphthyl) -1,1 '
Examples include triphenyldiamines such as -biphenyl-4,4'-diamine and starburst type molecules.

The electron-transporting material used in the present invention is not particularly limited, and any compound commonly used as an electron-transporting material may be used. Specific examples of the electron transport material include, for example, 2- (4-biphenylyl) -5- (4
-T-butylphenyl) -1,3,4-oxadiazole, bis {2- (4-t-butylphenyl) -1,3,
Examples thereof include oxadiazole derivatives such as 4-oxadiazole} -m-phenylene, triazole derivatives, and quinolinol-based metal complexes.

The light-emitting material used in the present invention is not particularly limited, and any compound commonly used as a light-emitting material may be used. For example, distyrylarylene derivatives (JP-A-2-247278, JP-A5-1)
7765), coumarin derivatives, dicyanomethylenepyran derivatives, perylene derivatives (JP-A-63-2646).
92), and aromatic ring materials (Japanese Patent Laid-Open No. 8-298).
186, JP-A-9-268284) and anthracene compounds (JP-A-9-157643, JP-A-9-156843).
-268283, JP-A-10-72581), quinacridone derivative (JP-A-5-70773) and the like.

The anode of the organic EL element plays a role of injecting holes into the hole transport layer, and it is effective that it has a work function of 4.5 eV or more. Specific examples of the anode material used in the present invention include indium tin oxide alloy (ITO), tin oxide (NESA), gold, silver, platinum and copper. As the cathode, a material having a small work function is preferable for the purpose of injecting electrons into the electron transport band or the light emitting layer. The cathode material is not particularly limited, but specifically, indium, aluminum, magnesium, magnesium-indium alloy, magnesium-aluminum alloy, aluminum-lithium alloy, aluminum-scandium-lithium alloy, magnesium-silver alloy and the like can be used.

The method of forming each layer of the organic EL element in the present invention is not particularly limited and can be appropriately selected from known methods. Examples thereof include a vacuum vapor deposition method, a molecular beam vapor deposition method (MBE method), a dipping method of a solution dissolved in a solvent, a spin coating method, a casting method, a bar coating method, a roll coating method, and the like.

[0049]

EXAMPLES Examples of the present invention will be described in detail below.

(Example 1) A positive resist material AZP-FP650F5 (manufactured by Clariant Japan Co., Ltd.) was formed as a photosensitive material on a quartz substrate to a thickness of 4000 liters.
The photosensitive material was exposed with a two-beam laser interference exposure system. The laser light source is an Ar ion laser with a wavelength of 48.
8 nm was used. A photomask for pixel formation was set on the optical path of one light flux (intensity 100 mW / cm ² ) after passing through the beam expander. After that, the beam splitter splits the laser beam into two light beams, and the mirror is used to expose the substrate so that the crossing angle becomes 90 ° (exposure time: 15
Second). The exposure area of the interference exposure unit is 0.30 mm ^2.
And

After exposure, organic alkali developer AZ300M
When exposed to IF (manufactured by Clariant Japan), the exposed portion was dissolved. As a result of SEM observation, a diffraction grating with a pitch of about 345 nm was obtained. It was confirmed that there was no change in the film thickness of the photosensitive material around the diffraction grating and there was no exposure to non-interfering light.

The produced quartz substrate with a resist pattern was etched by reactive gas etching. CF ₄ is used as a reactive gas for etching, and traveling wave 100
W, anode current 120 mA, reflected wave 0 W, anode voltage 1.4
It was performed under the conditions of 5 kW and a voltage of -250V. It was possible to dig about 1500 Å quartz substrate by etching for 20 minutes. After etching, the resist material was removed with a remover and the substrate was dried. A chemical vapor deposition (CVD) method was used to form a 1.2 μm thick SiN _x film on the substrate. After that, ITO was deposited by a sputtering method so that the sheet resistance was 20Ω / □.

Next, the following two layers were formed as organic layers on the ITO. First, as a hole transport layer, N, N'-diphenyl-N, N'-bis- (1-naphthyl) -1,1'-biphenyl-4,4'-diamine (α-NPD) was deposited by vacuum deposition. To a thickness of 50 nm, and then tris (8-quinolinol) aluminum (Alq) was formed to a thickness of 70 nm as a light emitting layer by a vacuum evaporation method. Next, a magnesium-silver alloy was co-deposited by a vacuum vapor deposition method at a vapor deposition rate ratio of 10: 1 as a cathode to form a film having a thickness of 150 nm, thereby forming an organic EL device. The area of the light emitting portion was 0.25 mm ² .

When a DC voltage of 5 mA / cm ² was applied to this device, light emission of 275 cd / m ² was obtained. It was confirmed that the luminous efficiency was improved as compared with Comparative Example 1.

Example 2 A G-line positive resist material AZP-FP650F5 as a photosensitive material on a quartz substrate.
(Manufactured by Clariant Japan Co., Ltd.) was formed into a film having a thickness of 4000Å. Next, the photosensitive material was exposed with three dual-beam laser interference exposure systems. The three laser light sources are incoherent to each other. The first two-beam laser interference exposure system splits a laser beam (intensity 100 mW / cm ² ) having a wavelength of 488 nm (Ar ion laser) into two beams with a beam splitter, and intersects this substrate at a crossing angle θ = 120 °. The second two-beam laser interference exposure system uses a beam splitter to generate a laser beam (intensity 100 mW / cm ² ) having a wavelength of 488 nm (Ar ion laser).
It is divided into books and crossed on this substrate at a crossing angle θ = 90 °. The third two-beam laser interference exposure system is a laser beam (intensity 100 mW / cm ² ) having a wavelength of 488 nm (Ar ion laser). 2) is divided into two by a beam splitter and crossed at a crossing angle θ = 70 ° on this substrate.

For three three-beam laser interference exposure systems, one
A mask for forming two pixels is arranged on the light path before the light beam is divided into two by the light beam section, that is, the beam splitter. With the mask on the first two-beam laser interference exposure system, the mask on the first two-beam laser interference exposure system, and the mask on the third two-beam laser interference exposure system, three types of diffraction gratings are formed on the photosensitive material. The size of 300 μm in length and 100 μm in width can be arranged alternately. The thickness of the photomask was 100 μm.

Interference exposure is performed simultaneously by three two-beam laser interference exposure systems. The exposure time was 15 seconds. After the exposure, it was treated with an organic alkali developer AZ300MIF (manufactured by Clariant Japan Co., Ltd.) to dissolve the exposed portion. As a result, a diffraction grating having a pitch of about 280 nm is obtained in the portion exposed by the first two-beam laser interference exposure system, and about 345 n in the portion exposed by the second two-beam laser interference exposure system.
A diffraction grating with an m pitch was obtained, and a diffraction grating with a pitch of about 425 nm was obtained in the portion exposed by the third two-beam laser interference exposure system. The boundary between the three types of diffraction gratings was 20 μm, but no decrease in the resist film thickness around each pixel due to non-interference exposure was observed.

The produced quartz substrate with a resist pattern was etched by reactive gas etching. At this time,
CF4 is used as a reactive gas, traveling wave 100W, anode current 120mA, reflected wave 0W, anode voltage 1.45K.
The conditions of W and voltage -250V were used. It was possible to dig about 1500 Å quartz substrate by etching for 20 minutes. After etching, the resist material was removed with a remover and the substrate was dried. As a result, each diffraction grating is 300 vertical.
The size was 100 μm and the width was 100 μm, and they could be arranged at intervals of 20 μm.

(Comparative Example 1) Organic EL prepared in Example 1
In the device, all were the same except that the area of the diffraction grating was 0.25 mm ² and the area of the light emitting pixel electrode. When a direct current voltage of 5 mA / cm ² was applied to this element, 2
Light emission of 50 cd / m ² was obtained.

Comparative Example 2 The same as Example 2 except that a photomask having a thickness of 100 μm was brought into close contact with a photosensitive material and the photomask was moved to perform interference exposure sequentially. As a result, in the first, second, and third two-beam laser interference exposure systems, about 17 pixels are provided near both sides of the pixel, respectively.
Non-interference exposure areas of 0 μm, 100 μm, and 46 μm were observed. This part is developed and the resist film thickness is about 160.
It decreased to 0Å.

[0061]

As described above, according to the present invention,
A high-luminance and high-definition organic EL element can be realized. Furthermore, according to the manufacturing method of the present invention, three types of diffraction gratings can be manufactured simultaneously in the substrate, and the production efficiency is significantly improved.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of an organic EL device having a diffraction grating of the present invention.

FIG. 2 is a schematic diagram of a two-beam laser interference exposure system of the present invention.

FIG. 3 is a schematic view of forming a diffraction grating related to conventional two-beam laser interference exposure.

FIG. 4 is a schematic cross-sectional view of an organic EL element having RGB pixels of the present invention.

FIG. 5 is a schematic diagram of a multiple two-beam laser interference exposure system of the present invention.

[Explanation of symbols]

10, 13 Substrates including diffraction gratings 11, 12, 14 Substrates 20, 21, 22, 23 High refractive index layers 30, 31, 32, 33 Anodes (ITO) 40, 41, 42, 43 Organic layers 50, 51, 52 , 53 cathode 60, 61, 62, 63 light emission 70, 71, 72, 73 laser light source 80, 81, 82, 83 beam expander 90, 91, 92, 93, 94 photomask 100, 101, 102, 103 beam splitter 110, 111, 112 Laser light flux 120, 121, 122, 123, 124, 125, 1
26, 127 Mirrors 130, 131, 132 Photosensitive material 140 Laser crossing angles 150, 151 Non-interference exposure part 160 Interference exposure part

Claims (14)

[Claims] 1. An organic EL device comprising a single or a plurality of organic thin film layers sandwiched between an anode and a cathode and including a diffraction grating.
In the element, the organic EL element is characterized in that the area of the diffraction grating arranged in each light emitting pixel is larger than the area of the light emitting pixel. 2. The organic EL element according to claim 1, wherein the area of the light emitting pixel is 2 mm ² / pixel or less. 3. The light emitting pixels are R (red), G (green), and B.
3. The organic EL device according to claim 1, wherein there are three types (blue). 4. The organic EL device according to claim 3, wherein the diffraction gratings adjacent to the light emitting pixels made of RGB have different periods. 5. The period of the diffraction grating is 100 nm to 60 nm.
It is 0 nm, The organic EL element in any one of Claim 1 to 4 characterized by the above-mentioned. 6. An organic EL device comprising one or a plurality of organic thin film layers sandwiched between an anode and a cathode and including a diffraction grating.
In the device manufacturing method, the step of setting a photomask that determines the position and size of the diffraction grating in the substrate at the position where the laser non-interference exposure part is not formed on the surface of the photosensitive material, and the two-beam laser interference exposure system A method of manufacturing an organic EL device, comprising: exposing the photosensitive material; and forming a diffraction grating by etching the substrate or a thin film formed on the substrate. 7. The method for manufacturing an organic EL element according to claim 6, wherein at least one photomask is installed on the one-beam optical path before the laser beam splitting. 8. The method of manufacturing an organic EL device according to claim 6, wherein at least one photomask is provided in each optical path on the two-beam optical path after the laser light is split. 9. A plurality of two-beam laser interference exposure systems having the photomask are provided.
9. The method for manufacturing an organic EL element according to claim 8. 10. The method for manufacturing an organic EL device according to claim 9, wherein the plurality of two-beam laser interference exposure systems are incoherent to each other. 11. The cross beam angle of the two-beam laser interference exposure system is 150 degrees or less, and the two-beam laser interference exposure is performed from the same plane direction of the substrate. A method for producing an organic EL device according to item 1. 12. The organic EL device according to claim 8, wherein wavelengths or crossing angles of lasers used for the plurality of two-beam laser interference exposure systems are different. Production method. 13. The organic E according to claim 9, wherein there are three types of the two-beam laser interference exposure system, and each exposure is performed sequentially or simultaneously.
Manufacturing method of L element. 14. In the step of exposing the photosensitive resin by the two-beam laser interference exposure system, the exposure is performed from the substrate surface side coated with the photosensitive resin, and the other substrate surface is provided with a light absorbing plate. 14. The method for manufacturing an organic EL device according to claim 6, wherein