JP2014056839A - Device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique capable of efficiently processing formation of an organic compound layer by an inkjet system, at a high speed.SOLUTION: A method for forming an organic compound layer by an inkjet system is characterized in that a composition containing a luminescent organic compound is discharged from an ink head to form a continuous organic compound layer. The organic compound layer is formed on pixel electrodes arranged in a matrix and is continuously formed over a plurality of pixel electrodes. A light-emitting device using an organic light-emitting element is manufactured by the manufacturing method.

Description

The present invention relates to a method for manufacturing a light emitting device using an organic compound as a light emitter, and more particularly to a method for manufacturing a light emitting device using an ink jet method.

An organic light-emitting element is formed with a structure in which a thin film containing an organic compound capable of obtaining fluorescence or phosphorescence is sandwiched between a pair of electrodes composed of an anode and a cathode. The light emission mechanism is such that electrons injected from the cathode and holes injected from the anode are recombined in the light emitting layer containing a luminescent substance to form molecular excitons, and the molecular excitons return to the ground state. It is perceived as a phenomenon that emits light. The process of emitting light includes light emission from a singlet state (fluorescence) and light emission from a triplet state (phosphorescence). The luminance ranges from several thousand to several tens of thousands cd / m ² even at an applied voltage of 10 V or less, and light emission from blue to red is possible by appropriately selecting an organic compound material and its dopant.
Therefore, it is considered that it can be sufficiently applied to a display device or the like even in principle.

As for organic compounds, both high molecular compounds and low molecular compounds have been studied and developed. However, since both have low heat resistance, it is difficult to apply a patterning process such as photolithography. The ink jet method has been developed to overcome this problem, and a patterning process by photolithography is unnecessary by drawing a pattern directly on a substrate.

Regarding the ink jet system, Japanese Patent Application Laid-Open No. 10-012377 discloses a technique for manufacturing an active matrix organic EL display. In this method, a pixel electrode is formed on a glass substrate having a thin film transistor, and red, green, and blue light emitting layers are formed on the pixel electrode by an inkjet method for each pixel.

Organic compound materials used in the inkjet method include precursors such as cyanopolyphenylene vinylene and polyphenylene vinylene, derivatives such as aromatic diamine, oxydiazole, distilarylene, triphenylamine, and distyryl, quinolinol-based metals, azomethine zinc, Complexes such as porphyrin zinc, benzoxazole zinc, and phenanthroline upium are known.

The organic compound is dropped from an ink head of an ink jet printing apparatus in a state of being dissolved or dispersed in a solvent (hereinafter referred to as a composition) to form a film on the substrate. As physical properties of the composition, viscosity, surface tension, drying speed and the like are important parameters. Further, in order to drop the composition with good reproducibility, the geometric structure of the ink head and its driving conditions are important, and the amount, direction, period, etc. of the composition to be ejected are parameters.

In the ink jet system, in order to eject the composition from the ink head, a piezoelectric element is used, and the volume of the container filled with the composition is changed using the vibration to eject the composition to the outside. Yes.

The amount of the composition discharged from the ink head at one time is 10 to 40 pl, and the viscosity is 1 to 20 cp.
Is considered good. When the viscosity is low, a predetermined film thickness cannot be obtained, and there arises a problem that the composition flows onto the surface to be formed and then flows out and the pattern spreads more than necessary. In addition, if the viscosity is too high, the composition cannot be smoothly ejected from the ejection port of the ink head, or the shape of the ejected composition of the drop is like a thread, causing a shape defect after landing. There is.

As the solvent in the composition, those which volatilize after being dropped onto the substrate are suitable. However, if it is not continuously dripped, the solvent evaporates and hardens at the discharge port. For example, when a highly volatile solvent such as toluene is used, special care is required. Even when the discharge is continuous, solid matter gradually grows in the vicinity of the discharge port, and in the worst case, the discharge port is blocked. Even if it does not lead to this, the solid material formed in the vicinity of the discharge port changes the direction of the composition to be discharged, and the landing accuracy is significantly reduced. Furthermore, since the diameter of the discharge port is reduced, the amount of the composition to be discharged is reduced, resulting in a defect that the thickness of the organic compound layer formed on the substrate is reduced.
In order to prevent such inconveniences, the conventional ink jet method has been required to frequently clean the ink head in order to prevent clogging due to solid matter.

The present invention has been made in view of such problems, and an object of the present invention is to provide a technique capable of efficiently and rapidly processing the formation of an organic compound layer by an inkjet method.

In order to solve this problem, according to the present invention, in a method for forming an organic compound layer by an ink jet method, a composition containing a light-emitting organic compound is ejected from an ink head to form a continuous organic compound layer. It is characterized by. The organic compound layer is formed on pixel electrodes arranged in a matrix, and the organic compound layer is formed continuously over a plurality of pixel electrodes. And the light-emitting device using an organic light emitting element is manufactured with this manufacturing method.

The present invention can be applied to a method of manufacturing a light emitting device in which organic light emitting elements are arranged in a matrix to form a pixel portion. In order to employ the active matrix driving method, a pixel electrode is formed on a substrate having a thin film transistor, and a hole injection layer is formed on the pixel electrode upper layer.
A continuous organic compound layer is formed on the upper layer by discharging a composition containing a light-emitting organic compound from the ink head.

In the composition discharged onto the surface to be formed on the substrate, an organic compound layer is formed when the solvent volatilizes and solidifies. However, when the composition adheres in the form of polka dots due to the surface tension, an organic compound layer having a uniform thickness cannot be obtained. As a smoothing means, gas is ejected from a nozzle to smooth the composition. Alternatively, using a spatula or the like, the surface of the composition formed continuously may be smoothed and smoothed.

When an inert gas such as nitrogen or argon is used as the gas to be ejected, the solvent of the composition can be volatilized and oxidation can be prevented. Alternatively, an opening is provided concentrically around the outer periphery of the discharge port, and smoothing is performed by ejecting gas from the opening, and the composition is dried and solidified at the discharge port to prevent clogging. Can do.

In the present invention, a composition having a light-emitting property used for pattern formation by an ink jet method is obtained by dissolving or dispersing an organic light-emitting material or a precursor thereof in a solvent. For example, it has no sublimation property and the number of molecules is 20 or less, or the length of chained molecules is 10 μm.
The following organic compounds (which are referred to as medium molecular compounds in this specification) can be used.

In addition, an example of a composition having a light-emitting property used when forming a pattern by an ink jet method is a composition containing a polymer compound such as polyparaphenylene vinylene, polyparaphenylene, polythiophene, or polyfluorene. Can be applied. In order to change the luminescent color of an organic light-emitting device produced by the composition, the object can be achieved by including at least one fluorescent dye that changes the luminescent property in the luminescent composition.

In the conventional ink jet method, a predetermined pattern is formed by repeatedly performing operations of ink head position control and composition ejection, but the composition ejected for each dot is continuously formed on the substrate. By forming a linear or striped organic compound layer,
The time required for alignment is shortened, the formation of the organic compound layer is facilitated, and the processing time can be shortened.

In particular, the present invention is suitable for application to a production system in which a plurality of display panels are cut out from a single large-area substrate. When a plurality of pixel regions are provided on a large area substrate,
By instantaneously stopping the discharge of the mixture during the movement between the pixel regions, the ink head can be moved at a higher speed with respect to the large area substrate.

As described above, according to the present invention, the time required for alignment is shortened by forming a linear or striped organic compound layer by causing the composition ejected for each dot to continue on the substrate. Formation of the compound layer is facilitated, and the processing time can be shortened.

In particular, the present invention is suitable for application to a production system in which a plurality of display panels are cut out from a single large-area substrate. When a plurality of pixel regions are provided on a large area substrate,
By instantaneously stopping the discharge of the mixture during the movement between the pixel regions, there is an advantageous effect that the ink head can be moved at a higher speed with respect to the large area substrate and the productivity can be improved.

The figure for demonstrating the concept which forms an organic compound layer continuously with the inkjet system of this invention. FIG. 5 illustrates a configuration of an inkjet printing apparatus. FIG. 3 is a cross-sectional view illustrating an example of the configuration of an ink head. FIG. 3 is a cross-sectional view illustrating an example of the configuration of an ink head. FIG. 3 is a cross-sectional view illustrating an example of the configuration of an ink head. The figure explaining the process in which a continuous organic compound layer is formed. The figure explaining the process in which a continuous organic compound layer is formed. The figure explaining the concept which forms an organic compound layer continuously with respect to each pixel electrode arranged in the matrix form. The figure explaining the concept which forms an organic compound layer continuously with respect to each pixel electrode arranged in the matrix form. The figure for demonstrating the concept which forms an organic compound layer continuously with the inkjet system of this invention. The figure which shows arrangement | positioning of the discharge outlet in a head part. Sectional drawing explaining the manufacturing process of the organic light-emitting device using an inkjet system. Sectional drawing explaining the manufacturing process of the organic light-emitting device using an inkjet system. FIG. 6 is a top view illustrating a structure of a pixel provided with an organic light emitting element. Sectional drawing explaining the structure of the pixel which provided the organic light emitting element. Sectional drawing which shows an example in the sealing structure of a light-emitting device. 2A and 2B are a top view and a cross-sectional view illustrating a structure of a light-emitting device driven by an active matrix. FIG. 11 is a perspective view illustrating a structure of a pixel portion of a passive light emitting device. FIG. 11 illustrates an example of an electronic device. FIG. 11 illustrates an example of an electronic device.

Embodiments of the present invention will be described with reference to FIGS. FIG. 1 shows a stage in which a data line driving circuit 104 is formed on a substrate 101 and an organic compound layer is formed on the pixel portion 102 by an inkjet method. A partition wall 105 is provided in a stripe shape in the pixel portion 102, and an organic compound layer is formed between the partition walls. The partition wall 105 is provided to prevent adjacent organic compound layers from being mixed with each other when the organic compound layer is formed by the inkjet method.

The organic compound layer 106 is formed by discharging a composition containing a light-emitting organic compound material from the ink head 107. The composition is continuously ejected from the ink head to form a linear pattern. The material of the organic compound layer is not particularly limited, but organic compound layers 106R, 106G, and 106B that emit red, green, and blue colors are provided for color display.

When forming an organic compound layer using a polymer material suitable for the inkjet method, a single layer structure may be used, but a laminated structure of two or more layers is preferable in order to further improve luminous efficiency. A typical laminated structure is obtained by laminating a hole transport layer and a light emitting layer.

As a high molecular weight organic compound forming the organic compound layer, a substance soluble in an organic solvent such as a polyparaphenylene vinylene derivative, a polythiophene derivative, a polyfluorene derivative, a polyparaphenylene derivative, a polyalkylphenylene, or a polyacetylene derivative should be used. Can do.

Examples of polyparaphenylene vinylene derivatives include poly (2,5-dialkoxy-1,4-
Phenylene vinylene): RO-PPV can be used, specifically, poly (2-methoxy-5- (2-ethyl-hexoxy) -1,4-phenylene vinylene): MEH-PPV
And poly (2,5-dimethyloctylsilyl-1,4-phenylenevinylene): DMOS-
A material such as PPV can be used.

As the polyparaphenylene derivative, poly (2,5-dialkoxy-1,4-phenylene): RO-PPP can be used.

As the polythiophene derivative, poly (3-alkylthiophene): PAT can be used, and specifically, a material such as poly (3-hexylthiophene): PHT, poly (3-cyclohexylthiophene): PCHT can be used. . In addition, poly (3-
(Cyclohexyl-4-methylthiophene): PCHMT, poly (3- [4-octylphenyl] -2,2′bithiophene): PTOPT, poly (3- (4 octylphenyl) -thiophene): POPT-1, etc. You can also.

As the polyfluorene derivative, poly (dialkylfluorene): PDAF can be used, and specifically, a material such as poly (dioctylfluorene): PDOF can be used.

Examples of the polyacetylene derivative include polypropylphenylacetylene: PPA-iPr,
Materials such as polybutylphenylphenylacetylene: PDPA-nBu and polyhexylphenylacetylene: PHPA can be used.

Moreover, as a solvent of these high molecular organic compounds, toluene, benzene, chlorobenzene, dichlorobenzene, chloroform, tetralin, xylene, anisole, dichloromethane, gamma butyllactone, butyl cellosolve, cyclohexane, NMP (N-methyl-
2-pyrrolidone), dimethyl sulfoxide, cyclohexanone, dioxane or TH
F (tetrahydrofuran) or the like can be used.

In addition, PEDOT (poly (3,4-ethylene dioxythioph
ene)) or polyaniline (PA). These materials are water-soluble. This PEDOT can also be formed by a coating method. A second organic compound layer can also be formed by an inkjet method on the first organic compound layer (PEDOT) formed by a coating method.

In addition, it has no sublimation property and the number of molecules is 10 or less, or the length of chained molecules is 5 μm.
It is also possible to use m or less organic compounds (referred to as medium molecular organic compounds). An example of such a material is tetrakis (2-mercapto-benzoxazolato) tungsten. In pattern formation by ink jet method using high molecular organic compound materials, there is a problem that the dropped mixture becomes a linear shape by pulling the thread, but in the case of medium molecular organic compounds with a small number of linked molecules, Such a problem does not occur. Further, when a mixture of polymer organic compound materials is formed, it is necessary to consider a combination of a solvent for dissolving the mixture and members constituting the ink head. In practice, it is necessary to use a solvent that does not corrode the members constituting the ink head. However, medium molecular organic compounds can be used by being dispersed in an aqueous solution, and such a problem does not occur.

As the solvent, toluene, benzene, chlorobenzene, dichlorobenzene, chloroform, tetralin, xylene, dichloromethane, cyclohexane, NMP (N-methyl-2-pyrrolidone), dimethyl sulfoxide, cyclohexanone, dioxane, THF
(Tetrahydrofuran) can be applied.

FIG. 2 shows a configuration of a printing apparatus using an ink jet system. Ink head 201
The composition discharged from the substrate is formed so that a continuous organic compound pattern is formed on the substrate.
The discharge cycle and the moving speed of the substrate are adjusted. Adjacent to the ink head 201, a nozzle 202 for ejecting gas is provided as a means for smoothing the composition (or organic compound). It is used to smooth the composition discharged onto the substrate 215 by the gas ejected from this nozzle. Further, in order to increase the accuracy of the landing position of the ejected composition, the distance between the ink head 201 and the substrate 215 is made close to 1 mm or less. In this configuration, a moving mechanism 204 that moves the ink head 201 up and down and its control means 203 are provided so that the ink head 201 can be brought close to the substrate 215 only during pattern formation.

Other configurations include a substrate stage 205 that fixes the substrate, moves in the XYθ direction, and fixes the substrate by a technique such as a vacuum chuck, means 206 for supplying a composition to the ink head 201, nozzle 2
And means 207 for supplying a gas to 02. The casing 210 is an ink head 201.
If the atmosphere is replaced by supplying the same gas as the solvent of the composition by the gas supply means 208 and the shower head 209 provided in the housing 210 by covering the substrate stage 205 and the like, drying is prevented to some extent. Can be printed for a long time. As other accompanying elements, a cassette 212 for holding a substrate to be processed, a conveying means 211 for carrying in and out of the cassette 212, a clean unit 213 for sending clean air and reducing dust in the work area.
Etc. may be provided.

An ink head that discharges a composition for forming an organic compound layer plays an important role in determining pattern accuracy. FIG. 3 shows an example of the configuration, and the case 301 includes a piezoelectric element 302.
The pressure generating chamber 304 is sealed on one surface by an elastic plate 303 to which is attached, and a reservoir 305 for temporarily storing the supplied composition. An opening is formed at one end of the pressure generating chamber 304, and a discharge port 306 is provided through which the composition is discharged. Pressure generation chamber 30
The elastic plate 303 constituting 4 changes the volume of the pressure generating chamber 304 by the deflection displacement of the piezoelectric element 302 and discharges the mixture. The nozzle 307 in which the opening 308 used as the smoothing means is formed ejects gas toward the substrate surface, and is an ejection port 306 of the ink head.
It is provided in the vicinity.

FIG. 4 shows another example of the ink head. In this ink head configuration, a piezoelectric element 402 and an elastic plate 403 are provided in a housing 401, and similarly, a mixture can be continuously discharged. A discharge port 406 provided in the pressure generation chamber 404 has a concentric opening 4 at its outer periphery.
08 is provided, and the gas can be smoothed by ejecting gas from the opening 408. In addition, if a gas having the same quality as the solvent of the composition is used as the gas, the composition can be prevented from being dried and solidified at the discharge port 406.

FIG. 5 shows a configuration of an ink head in which the composition is extruded using a compressed gas and continuously supplied onto the surface to be formed. A passage through which the composition flows is formed in the housing 501, a diaphragm valve 503 is provided in the middle, and a needle valve 502 is provided in the discharge port 513. Both are for controlling the supply of the composition, but the needle valve 502 is provided for instantaneously switching the supply amount and supply of the composition. The composition is supplied from the reservoir 505 using the compressed gas supply means 506. The supply amount is detected by a detector using ultrasonic waves (consisting of an ultrasonic head 504 and a detection circuit 507), and the information is input to the arithmetic processing unit 512 via the A / D converter 508. The arithmetic processing unit 512 transmits / receives a signal to / from an external information processing apparatus via an interface, or performs A / D or D / A converters 509 to 5.
11 is used to control various valves. A linear pattern can also be formed by such a configuration.

Although there may be only one ejection port provided in the ink head, a plurality of ejection ports may be provided in order to perform printing more efficiently. For example, a pair of pressure generation chambers and discharge ports may be provided in a pair, or a set of pressure generation chambers may be associated with a plurality of discharge ports.

FIG. 6 shows a step-by-step method of forming a linear organic compound layer by ejecting the composition from the ink head 601 onto the surface 600 to be formed on the substrate. FIG. 6A shows an initial state, and when forming a pattern on the surface 600, the ink head 6 as shown in FIG.
01 and the nozzle 602 come close to the surface to be formed, and discharge of the composition 604 is started.

Then, as shown in FIG. 6C, a linear pattern 605 is formed by relatively moving the ink head 601 and the surface 600 to be formed. The pattern can be smoothed by the gas ejected from the smoothing means 602. The ink head 601 that has reached a predetermined position stops discharging the composition (FIG. 6D), and then moves away from the formation surface 600 (FIG. 6E).
Thus, a continuous organic compound layer pattern having a predetermined thickness can be formed on the formation surface 600.

Further, FIG. 7 shows stepwise another method in which the ink head 701 discharges the composition onto the surface 700 to be formed on the substrate to form a linear organic compound layer. FIG. 7 (A)
Is an initial state, and when forming a pattern on the formation surface 700, the ink head 701 comes close to the formation surface as shown in FIG. 7B, and ejection of the composition 702 starts.

Then, as shown in FIG. 7C, a linear pattern 703 is formed by relatively moving the ink head 701 and the surface 700 to be formed. The pattern of the organic compound to be formed is controlled by the distance between the ink head 701 and the surface 700 to be formed, in addition to the discharge amount of the composition.
The ink head 701 that has reached a predetermined position stops discharging the composition, and then moves away from the formation surface 700 (FIG. 7D). In this manner, a continuous organic compound layer pattern can be formed on the formation surface 700.

FIG. 8 shows an example of a pixel portion in which organic compound layers 801 to 803 are formed.
This pixel portion includes a gate line 804, a data line 805, a power supply line 806, a pixel electrode 811,
Semiconductor layers 809 and 810 are provided, and thin film transistors 820 and 830 are formed using these semiconductor layers. The pixel electrode 811 is connected to the thin film transistor 830. And it arranges in matrix form and forms the pixel part as a whole. The organic compound layer is formed using the ink head described in FIG. 3 or FIG. 4, and the composition ejected for each droplet is continuously formed on the pixel electrode to form a linear organic compound layer as a whole. .

FIG. 9 shows an organic compound layer 85 using the ink head shown in FIG.
The example which formed 1-853 is shown. In this case, since the composition is continuously supplied, the organic compound layer formed on the upper layer of the pixel electrode is also formed in a linear shape or a stripe shape. still,
These organic compound layers may be formed with an organic compound layer that emits light corresponding to red, green, blue, or the like when performing color display.

FIG. 10 shows an example in which an organic compound is applied all at once to all the pixel columns formed in the pixel portion. The head unit 20 has the same number of ejection openings as the number of pixel rows. With such a configuration, it becomes possible to form organic compound layers in all the pixel columns in one scan, and the throughput is dramatically improved.

In addition, the pixel unit may be divided into a plurality of zones, and a head unit provided with ejection openings in the same number as the number of pixel columns included in the zone may be used. That is, if the pixel portion is divided into n zones, the organic compound layer can be formed in all the pixel columns by scanning n times.

Actually, the pixel size may be as small as several tens of μm, and thus the width of the pixel column may be about several tens of μm. In such a case, it is difficult to arrange the discharge ports in a horizontal row, so it is necessary to devise the arrangement of the discharge ports. FIG. 11 shows an example in which the mounting position of the ejection port with respect to the ink head is changed. FIG. 11A shows an example in which the ejection ports 52 a to 52 c are formed in the ink head 51 while shifting the position obliquely. 52a is a discharge port for applying the red light emitting layer composition, 52b is a discharge port for applying the green light emitting layer composition, and 52c is a discharge port for applying the blue light emitting layer composition. is there. Further, each one of the arrows corresponds to a pixel column.
With such an arrangement of the discharge ports, the organic compound layer can be formed without interference between adjacent discharge ports even when the pitch of the pixel rows is narrowed.

As indicated by 53, the discharge ports 52a to 52c are used as one unit, and one or more units are provided in the head portion. If there is one unit 53, the composition is applied simultaneously to three pixel columns, and if there are n units 53, the composition is applied simultaneously to 3n pixel columns. . With such a configuration, the degree of freedom of the arrangement space of the discharge ports is increased, and the present invention can be carried out on a high-definition pixel portion without difficulty. In addition, FIG.
1 (A) ink head 51 can be used to process all pixel columns in the pixel portion at once, or the pixel portion can be divided into a plurality of zones and processed in several times. It is.

Next, the ink head 54 shown in FIG. 11B is a modification of FIG. 11A, and is an example in which the number of nozzles included in one unit 55 is increased. In the unit 55, the discharge port 56a for applying the composition for the red light emitting layer, and the discharge port 56b for applying the composition for the green light emitting layer.
Two discharge ports 56c for applying the blue light emitting layer composition are included, and one unit 55 is included.
As a result, the organic compound is simultaneously applied to a total of six pixel columns.

In this embodiment, only one or a plurality of the units 55 are provided. If the number of units 55 is one, the composition is applied simultaneously to six pixel rows. The composition is applied simultaneously to the pixel columns of the book. Of course, the number of nozzles provided in the unit 55 is six.
It is not necessary to limit to the number, and it is also possible to provide a plurality. In the case of such a configuration, as in the case of FIG. 11A, all the pixel columns in the pixel portion can be processed at once, or the pixel portion is divided into a plurality of zones and divided into several times. Can be processed.

An ink head 57 as shown in FIG. 11C can also be used. Ink head 5
Reference numeral 7 denotes a discharge port 5 for applying a red light emitting layer coating liquid with a space for three pixel columns.
8a, a discharge port 58b for applying the green light emitting layer coating solution and a discharge port 58c for applying the blue light emitting layer coating solution are provided. After the ink head 57 is scanned once and the composition is applied to the pixel rows, the ink head 57 is then shifted to the right by three pixel rows and scanned again. Further, the ink head 57 is shifted to the right by three pixel rows and scanned again. By performing three scans as described above, the composition can be applied in stripes arranged in the order of red, green, and blue. In the case of such a configuration, as in the case of FIG. 11A, all the pixel columns in the pixel portion can be processed at once, or the pixel portion is divided into a plurality of zones and divided into several times. Can be processed.

As described above, by using the present invention, the composition is continuously discharged, and the organic compound layer is continuously formed, so that the time for position control when printing the organic compound layer is shortened, and the printing speed is increased. Can be improved.

As shown in FIG. 12A, 40 transparent pixel electrodes 1201 to 1204 are formed on a substrate 1200.
It is formed at a pitch of ˜120 μm and a thickness of 0.1 μm. As a material for forming the transparent pixel electrode, indium oxide, zinc oxide, tin oxide, or a mixture of these oxides is used.

Next, as shown in FIG. 12B, a partition wall 1205 made of a resin material is formed between the patterns of the transparent pixel electrodes. The partition wall has a thickness of 1 to 2 μm and a width of 20 μm, and is formed so as to cover the end of the transparent pixel electrode. The partition walls are provided to prevent the composition discharged and landed from the ink head from flowing out and mixing with adjacent pixels.

Next, with respect to the glass substrate 1200 having the transparent pixel electrodes (anodes) 1201 to 1204, a poly (ethylenedioxythiophene) / poly (styrenesulfonic acid) aqueous solution (hereinafter referred to as PEDOT / PSS) is used as the first organic compound layer. ) To a thickness of 30 nm by spin coating. This PEDOT / PSS acts as the hole injection layer 106 (FIG. 12 (C
)).

Thereafter, moisture is evaporated by heat treatment, and the composition is applied by an ink jet printing apparatus 1207 to form a light emitting layer as a second organic compound layer having a thickness of 0.05 to 0.2 μm. As the composition, a metal chelate complex having a π-conjugated ligand dissolved in an acetonitrile solution is used. For example, a composition having a viscosity of 1 to 20 cp and a diameter of about 80 μm is discharged to a 90 μm pitch pixel. This composition is heated at 80 to 120 ° C. after ink jet discharge to volatilize the solvent to form a light emitting layer 1208 having a thickness of 50 to 150 nm. The light emitting layer 1208 includes
As described in the embodiment mode, the composition to be discharged is overlapped to form a linear or striped layer (FIG. 12D).

Magnesium alloy (for example, AlMg) is used as the cathode 1209 by a vacuum deposition method.
The film is formed to a thickness of 0.2 μm. Thus, the light emitting device is completed (FIG. 12E).

FIG. 13 shows an example of manufacturing an active matrix driving type light emitting device by an ink jet method using the manufacturing method of the present invention. In FIG. 13A, a substrate 1300
Thin film transistors 1301 to 1303 which are active elements are formed thereover. A thin film transistor is composed of a semiconductor film for forming a channel formation region, source and drain regions, a gate electrode, a gate insulating film, and the like. The structure of the thin film transistor has features such as a top gate type and a bottom gate type, but the structure is not limited when applied to the present invention.

The pixel electrodes 1304 to 1306 connected to the source or drain region of the thin film transistor are formed with a pitch of 65 μm and a thickness of 0.1 μm, for example. When the organic compound layer is formed with such a narrow pitch by an ink jet method, the pattern of the present invention can be formed without any tailing or the like when the composition of the present invention is used. A partition 1308 made of a resin material is formed between the pixel electrode patterns. The partition wall layer has a thickness of 1 to 2 μm and a width of 20 μm.
It forms so that the edge part of a transparent pixel electrode may be covered. This partition wall is provided to prevent the composition discharged and landed from the ink head from flowing out and mixing with adjacent pixels (
FIG. 13 (A)).

Next, for the glass substrate 1300 including the thin film transistors 1301 to 1303, the first
Poly (ethylenedioxythiophene) / poly (styrenesulfonic acid) as organic compound layer
An aqueous solution (hereinafter referred to as PEDOT / PSS) is formed to a thickness of 30 nm by spin coating. This PEDOT / PSS acts as a hole injection layer 1308 (FIG. 13B
)).

Thereafter, moisture is evaporated by heat treatment, and the composition is applied by an ink jet printing apparatus 1309 to form a light emitting layer as a second organic compound layer having a thickness of 0.05 to 0.2 μm. As the composition, a metal chelate complex having a π-conjugated ligand dissolved in an acetonitrile solution is used. After discharging the ink jet, the composition is heated at 80 to 120 ° C. to volatilize the solvent to form the light emitting layer 1310 (FIG. 13C).

Magnesium alloy (for example, AlMg) as a cathode 1311 is 0.1 to 0.1 by vacuum deposition.
The film is formed to a thickness of 0.2 μm. Thus, an active matrix driving type light emitting device is completed (FIG. 13D).

Note that although the light emitting device shown in FIGS. 12 and 13 has an example in which it is formed with two layers of a hole injection layer and a light emitting layer, it is not limited to the structure, and the composition of the present invention is used. A light emitting layer and an injection layer associated therewith may be arbitrarily provided by an inkjet method.

A specific example of a light-emitting device manufactured by an inkjet method using the composition of the present invention will be described with reference to the drawings. FIG. 14 is a top view showing an example of a pixel structure of a light emitting device driven by an active matrix. FIG. 15 is a cross-sectional view corresponding to the line AA ′ in FIG. 14, and both drawings describe the structure of the pixel using common reference numerals.

In this pixel structure, two thin film transistors are provided in one pixel, one is an n-channel thin film transistor 1604 for the purpose of switching operation, and the other is a p-channel for the purpose of controlling the current flowing through the organic light emitting element. Type thin film transistor 1605.
Of course, in manufacturing an active matrix driving light emitting device using the ink jet printing apparatus of the present invention, the number of thin film transistors provided in one pixel is not limited.
An appropriate circuit configuration may be employed in accordance with the driving method of the light emitting device.

As shown in FIG. 15, the organic light emitting device 1575 includes a first electrode 1546, a hole injection layer 1571,
The light emitting layer 1572 and the second electrode 1573 are included. The first electrode and the second electrode can be distinguished into an anode and a cathode according to their polarities. The material for forming the anode is a material having a high work function such as indium oxide, tin oxide or zinc oxide, and the cathode is made of MgAg, AlMg, Ca, M
A material having a low work function formed of an alkali metal or an alkaline earth metal such as g, Li, AlLi, or AlLiAg, typically a magnesium compound, is used.

The p-channel thin film transistor 1605 and the n-channel thin film transistor 1604 are each an active layer 151 in which a channel formation region, a source and drain region, an LDD region, and the like are formed.
6 and 1517 are formed of a polycrystalline semiconductor film. Although the first gate electrodes 1533 and 1534 are formed via the gate insulating film 1518, the second gate electrode 1 is opposed to each other across the active layer.
506 and 1508 are provided via insulating films 1510 and 1511. Interlayer insulating film 15
43 and 1544 are formed by combining an inorganic insulating film and an organic insulating film. Wiring 150
Reference numeral 5 denotes a signal line based on video data, and a wiring 1507 is a power supply line for supplying a current to the organic light emitting element.

The first electrode 1546 of the organic light emitting element 1575 is a p-channel thin film transistor 1605.
The electrode 1553 is connected. The partition wall 1570 is formed for the purpose of separating adjacent pixels so that the composition does not reach adjacent pixels when a light emitting layer is formed by an inkjet method. The partition is made of a photosensitive or thermosetting resin material such as polyimide, acrylic, polyimide amide, or polybenzimidazole so as to cover the end of the first electrode. The organic compound layer may be formed continuously in the vertical direction or may be formed continuously in the horizontal direction.

The surface of the partition wall 1570 formed of a resin material may be surface-modified by plasma treatment using a rare gas such as argon to be hardened. The hole injection layer 1571 is formed by applying a poly (ethylenedioxythiophene) / poly (styrenesulfonic acid) aqueous solution (hereinafter referred to as PEDOT / PSS) to the entire surface of the substrate by a spin coating method, followed by drying.
It is formed to a thickness of 0 nm.

The light emitting layer is dispersed in a solvent using an inkjet printing apparatus, using poly (N-vinylcarbazole: PVK), which is a π-conjugated polymer material, as a host material and a metal chelate complex having a π-conjugated ligand as a guest material. The prepared composition is applied. The composition discharged from the ink head lands on the area surrounded by the partition walls. Then, the light emitting layer 1572 having a thickness of 0.1 to 0.2 μm is formed by heating at 80 to 120 ° C. in a nitrogen atmosphere.

A passivation film 1574 is formed thereon. For passivation film, silicon nitride, silicon oxynitride, diamond-like carbon (DLC)
For example, a material having a high barrier property against oxygen or water vapor is used.

As described above, an active matrix driving light-emitting device can be manufactured. By manufacturing a light-emitting device using the composition of the present invention, the light-emitting layer can be patterned with high accuracy, and the incidence of defective pixels that do not emit light can be reduced.

As shown in FIG. 16, a resin layer 1211 such as acrylic, polyimide, polyimide amide, or polybenzimidazole is formed on the light emitting device manufactured according to FIG. 12, and a sealing plate 1212 such as plastic or glass is further fixed thereon. Thus, a light-emitting device with high hermeticity can be obtained. By coating silicon nitride or DLC on the surface of the sealing plate 1212, the gas barrier property can be improved and the reliability of the light emitting device can be further improved.

In this embodiment, a mode of a light-emitting display device provided with an organic light-emitting element is shown in FIG. FIG.
) Is a top view showing the light-emitting device, and a cross-sectional view taken along line AA ′ is shown in FIG. A pixel region 1702, a source side driver circuit 1701, and a gate side driver circuit 1703 are formed over a substrate 1700 having an insulating surface (eg, a glass substrate, a crystallized glass substrate, or a plastic substrate). The organic compound layer in these pixel regions is formed by the inkjet method of the present invention. A known thin film transistor and circuit technology may be applied to the driver circuit.

Reference numeral 1718 denotes a sealing material, and 1719 denotes a DLC film. The pixel region and the driver circuit portion are covered with a sealing material 1718, and the sealing material is covered with a protective film 1719.
Further, the cover material 1720 is sealed with an adhesive. The cover material 1720 is preferably made of the same material as that of the substrate 1700, for example, a glass substrate in order to withstand deformation due to heat, external force, etc., and the concave shape (depth 3 to 10 μm) shown in FIG.
m). Further processed recess (depth 50-200 μm) where desiccant 1721 can be installed
) Is desirable. Reference numeral 1708 denotes a wiring for transmitting a signal input to the source side driver circuit 1701 and the gate side driver circuit 1703, and F is an external input terminal.
A video signal and a clock signal are received from a PC (flexible printed circuit) 1709.

Next, a cross-sectional structure will be described with reference to FIG. An insulating film 171 is formed over the substrate 1700
0, a pixel region 1702 above the insulating film 1710, and a gate side driver circuit 1703.
The pixel region 1702 is formed by a plurality of pixels including the current control thin film transistor 1711 and one electrode 1712 of the light emitting element electrically connected to the drain thereof. The gate side driver circuit 1703 is formed using a CMOS circuit in which an n-channel thin film transistor 1713 and a p-channel thin film transistor 1714 are combined.
These thin film transistors (including 1711, 1713, and 1714) may be manufactured according to a known technique.

The pixel electrode 1712 functions as an anode of the organic light emitting element. Further, partition walls 1715 are formed on both ends of the pixel electrode 1712, and an organic compound layer 1716 and a cathode 1717 of the organic light emitting element are formed on the electrode 1712 of the light emitting element. The organic compound layer 1716 is formed by appropriately combining a hole injection layer, a light emitting layer, an electron injection layer, and the like.
All of them may be formed by an inkjet printing technique, or may be formed by combining a spin coating method and an inkjet method.

For example, a first organic compound layer made of PEDOT can be formed as a hole injection layer, and a linear or striped second organic compound layer can be formed thereon using an inkjet printing apparatus. In this case, the second organic compound layer is a light emitting layer. The organic compound material to be applied can be a high molecular or medium molecular material.

The cathode 1717 also functions as a wiring common to all pixels, and is connected to the FP via the connection wiring 1708.
C1709 is electrically connected. Further, all elements included in the pixel region 1702 and the gate side driver circuit 1703 are covered with a cathode 1717, a sealing material 1718, and a protective film 1719. In addition, after completely covering the organic light emitting element with the sealing material 1718, it is preferable to provide a protective film 1719 made of a DLC film or the like on the surface (exposed surface) of the sealing material 1718 as shown in FIG. Further, a protective film may be provided on the entire surface including the back surface of the substrate. Here, it is necessary to pay attention so that a protective film is not formed on the portion where the external input terminal (FPC) is provided. A protective film may be prevented from being formed using a mask,
The protective film may not be formed by covering the external input terminal portion with a masking tape.

By encapsulating the organic light emitting element with the sealing material 1718 and the protective film with the structure as described above, the organic light emitting element can be completely shut off from the outside, and deterioration due to oxidation of the organic compound layer such as moisture and oxygen from the outside. It is possible to prevent a substance that promotes invasion. Therefore, a highly reliable light-emitting device can be obtained. Alternatively, the pixel electrode may be a cathode, and an organic compound layer and an anode may be stacked to emit light in a direction opposite to that in FIG.

FIG. 18 shows an example of the appearance of a light emitting device. A transparent pixel electrode (anode) 901 and a cathode 906 are provided so as to intersect each other, and an organic compound layer is formed therebetween. An insulating film 903 is formed between the transparent pixel electrodes (anodes) 901, and a partition wall 904 is formed thereon. However, this insulating film 903 may be omitted. The organic compound layer can be formed by appropriately combining spin coating methods in addition to the ink jet method. When the spin coating method is used, the film is also formed on the partition 904.

When the light emitting layer or the like is formed by an ink jet method, it does not have sublimation and has 1 molecule.
It is formed using an organic compound (medium molecular compound) having a length of 0 or less or a chained molecule of 10 μm or less. When pattern formation using an ink jet method is performed using this, a solution dissolved or dispersed in an aqueous, alcohol or glycol solvent is used. In any case, the viscosity can be adjusted to be applicable to pattern formation using an ink jet method, and film formation under optimum conditions can be performed easily and in a short time.

The composition ejected from the ink head is landed between the partition walls 904 and dried to form an organic layer 905 including a light emitting layer. As shown in FIG. 12, the organic compound layer 905 is formed by continuously forming partition walls 904 in a stripe shape. By forming the organic compound layer in this way, the light emitting layer can be efficiently patterned, and the incidence of defective pixels that do not emit light can be reduced.

Various electronic devices can be completed using a light-emitting device formed using the present invention. Examples of such electronic devices include video cameras, digital cameras, head mounted displays (goggles type displays), car navigation systems, projectors, car stereos, personal computers, personal digital assistants (mobile computers, mobile phones, electronic books, etc.), etc. Can be mentioned. Examples of these are shown in FIGS.

FIG. 19A illustrates a personal computer, which includes a main body 2001, an image input portion 2002, a display portion 2003, a keyboard 2004, and the like. A light-emitting device formed using the present invention can be incorporated in the display portion 2003 and a personal computer can be completed.

FIG. 19B illustrates a video camera, which includes a main body 2101, a display portion 2102, and an audio input portion 210.
3, an operation switch 2104, a battery 2105, an image receiving unit 2106, and the like. A light-emitting device formed using the present invention can be incorporated in the display portion 2102 and a video camera can be completed.

FIG. 19C illustrates a mobile computer (mobile computer), which includes a main body 2201.
, A camera unit 2202, an image receiving unit 2203, an operation switch 2204, a display unit 2205, and the like. A light-emitting device formed using the present invention can be incorporated in the display portion 2205 and a mobile computer can be completed.

FIG. 19D illustrates a goggle type display including a main body 2301, a display portion 2302, an arm portion 2303, and the like. A light-emitting device formed using the present invention can be incorporated in the display portion 2302 and a goggle-type display can be completed.

FIG. 19E shows a player using a recording medium (hereinafter referred to as a recording medium) on which a program is recorded. The main body 2401, a display portion 2402, a speaker portion 2403, and a recording medium 2404.
Operation switch 2405 and the like. This player is a DVD (Digit
al Versatile Disc), CD, etc., music appreciation, movie appreciation, games and the Internet can be performed. A light-emitting device formed using the present invention can be incorporated in the display portion 2402 and a goggle-type display can be completed.

FIG. 19F illustrates a digital camera, which includes a main body 2501, a display portion 2502, and an eyepiece portion 250.
3, an operation switch 2504, an image receiving unit (not shown), and the like. A light-emitting device formed using the present invention can be incorporated in the display portion 2502 and a digital camera can be completed.

FIG. 20A illustrates a mobile phone, which includes a main body 2901, an audio output unit 2902, and an audio input unit 29.
03, display unit 2904, operation switch 2905, antenna 2906, image input unit (CCD
2907 and the like. The light emitting device formed using the present invention is a display unit 2.
The digital camera can be completed.

FIG. 20B illustrates a portable book (electronic book), which includes a main body 3001 and display portions 3002 and 300.
3, a storage medium 3004, an operation switch 3005, an antenna 3006, and the like. A light-emitting device formed using the present invention can be incorporated in the display portions 3002 and 3003 and a portable book can be completed.

FIG. 20C illustrates a display, which includes a main body 3101, a support base 3102, and a display portion 3103.
Etc. A light-emitting device formed using the present invention can be incorporated in the display portion 3103 and a display can be completed. Note that FIG.
The display shown in FIG. 2 is a medium or small size display, for example, a screen size of 5 to 20 inches. In order to form a display portion having such a size, it is preferable to use a substrate having a side of more than 1 m and mass-produce it by performing multi-face drawing.

Claims (4)

A first nozzle;
A second nozzle provided concentrically on the outer periphery of the first nozzle,
The first nozzle discharges a composition containing an organic compound,
The second nozzle ejects an inert gas. A first nozzle;
A second nozzle provided close to the first nozzle,
The first nozzle opens a needle valve provided in the first nozzle, and continuously discharges a composition containing an organic compound,
The second nozzle ejects an inert gas. In claim 1 or 2,
An apparatus in which an inert gas is ejected from the second nozzle at the same time as the composition is ejected from the first nozzle. In claim 1 or 2,
At the same time as the composition is discharged from the first nozzle, an inert gas is jetted from the second nozzle, and the layer containing the organic compound is smoothed.

Images