JP2007258688A - Light-emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light-emitting device using an organic EL device as a light source, which has a small-size and a sufficient durability. <P>SOLUTION: The light-emitting device has an anode and a cathode, at least one light-emitting layer containing an organic material, sandwiched between the anode and cathode, and at least two pixels each made up of an element that emits light through the passage of an electric current between the electrodes, and is characterized in that: all of the pixels are formed on or above an identical substratum; at least one of the electrodes of each pixel is connected to a driving circuit independently on a pixel basis so that an applied voltage or current can be independently controlled; and in each of the pixels, if L<SB>1</SB>denotes the minimum distance between neighboring pixels and L<SB>2</SB>denotes the maximum width of the pixel, then L<SB>1</SB>×n≥L<SB>2</SB>(wherein, n is a number in the range from 0.1 to 3) and L<SB>2</SB>is no greater than 100 μm. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a light-emitting device having a light-emitting layer containing an organic substance, and in particular, a light-emitting device having two or more pixels capable of controlling an applied voltage (or current) independently (for example, ON / OFF control). About.

  In recent years, an organic electroluminescent device having a two-layer structure in which an organic fluorescent dye is used as a light-emitting layer and an organic charge transport compound used in an electrophotographic photoreceptor or the like is laminated (hereinafter sometimes referred to as an organic EL device). Is disclosed (Patent Document 1). The organic EL element has a feature that light emission of a large number of colors can be easily obtained in addition to low voltage driving and high luminance as compared with conventional inorganic EL elements. Many attempts have been reported on organic charge transport compounds (Non-Patent Documents 1 and 2).

In addition, polymer light-emitting elements (hereinafter sometimes referred to as polymer LEDs) using a high-molecular-weight light-emitting material (hereinafter referred to as polymer phosphor) are disclosed in Patent Documents 2 and 3 and Non-patent Document 3. Has been.
In Patent Document 2, a thin film of poly (p-phenylene vinylene) (hereinafter sometimes referred to as PPV) converted to a conjugated polymer is obtained by forming a soluble precursor on an electrode and performing a heat treatment. And an element using the same are disclosed.
Patent Document 3 discloses a conjugated polymer that is itself soluble in a solvent and does not require heat treatment. Non-Patent Document 3 also discloses a polymer fluorescent substance soluble in a solvent and a polymer LED produced using the same.

  In addition to the poly (p-phenylene vinylene), polyfluorene (Non-Patent Document 4), polyparaphenylene derivative (Non-Patent Document 5) and the like are disclosed as the polymer phosphor used in these polymer LEDs. Yes.

  As described above, a polymer LED uses a polymer fluorescent substance that is soluble in a solvent, and can easily form a light emitting layer by coating. Therefore, compared with the case of depositing a low molecular phosphor, It has the feature that it is advantageous for area reduction and cost reduction.

  Furthermore, a material that emits light (phosphorescence) from a triplet excited state is also known as a light-emitting material used for a light-emitting layer of a light-emitting element. As such a material, a polymer light emitting material (hereinafter sometimes referred to as a triplet polymer light emitting material) is also known in addition to a low molecular material.

  Conventional light-emitting elements such as organic EL elements, inorganic EL elements, semiconductor lasers, and inorganic LEDs (light-emitting diodes) are often used for display applications. In the case of a dot matrix element in which electrodes are combined in a grid pattern so that the pixels can be controlled independently, a plurality of pixels are connected to the drive circuit by the same electrode. In addition, a device that displays a number or a character by arranging a plurality of light emitting segments is known.

  Also, an optical system using a semiconductor laser and an optical system that combines a mirror and a lens is arranged to draw an image on a photoreceptor, and a plurality of inorganic LEDs are arranged in a line. An apparatus for forming an image using an LED array in the same manner has been developed.

  In an image forming apparatus using a semiconductor laser, since it is necessary to dispose an optical system and mechanically drive it, it is difficult to reduce the size. In addition, when an LED array is used, it is necessary to arrange a plurality of LED chips, and there is a problem that the image quality is deteriorated due to misalignment and variations in characteristics of the LED chips.

  An electrophotographic image forming apparatus using an organic EL element as a light source was reported by Oki Electric Industry in 1996 (Patent Documents 4 and 5). By using an organic EL element as a light source, a light-emitting element array can be formed at a time, so that miniaturization and cost reduction are expected. There have been several reports on optical printer heads thereafter (Patent Documents 6 and 7). .

  In addition, it has been reported that it is effective to limit the size of the dark spot in the initial state in order to reduce the influence of the dark spot, which is a practical problem (Patent Document 8). However, a device having sufficient characteristics for practical use has not been realized yet.

JP 59-194393 A WO90113148 published specification JP-A-3-244630 JP-A-8-48052 JP-A-8-244272 JP 2001-246780 A Japanese Patent Laid-Open No. 2002-19177 JP 2004-227975 A

Japanese Journal of Applied Physics (Jpn. J. Appl. Phys.) Vol. 27, L269 (1988) Journal of Applied Physics (J. Appl. Phys.), 65, 3610 (1989) Applied Physics Letters (Appl. Phys. Lett.), 58, 1982 (1991). Japanese Journal of Applied Physics (Jpn. J. Appl. Phys.) Volume 30, L1941 (1991) Advanced Materials (Adv. Mater.), Vol. 4, p. 36 (1992)

However, in the conventionally known device, in order to emit light with high luminance, if a large current is passed, the influence of heat generation and luminance decrease are large, and a sufficient lifetime cannot be obtained.
An object of the present invention is to provide a light-emitting device that uses an organic EL element as a light source and is small and has sufficient durability.

  As a result of intensive studies to solve the above-described problems, the present inventors have made significant improvements by specifying the pixel layout, the shape of the pixels, the light collecting characteristics of the light collecting functional elements constituting the image forming apparatus, and the like. It has been found that durability can be improved.

  By using the light emitting device of the present invention, an electrophotographic image forming apparatus or an image recording apparatus that is small and has sufficient durability and is inexpensive can be obtained.

Embodiments of the present invention are shown below.
The present invention is as follows.
(1) In a light-emitting device having an anode and a cathode, and a light-emitting layer containing at least one organic substance sandwiched between them, and having two or more pixels composed of elements that emit light by passing a current between the electrodes. All pixels are formed on or above the same substrate, and at least one of the electrodes of each pixel is independently connected to the drive circuit for each pixel, and the applied voltage or current can be controlled independently. If the minimum value of the interval between adjacent pixels is L ₁ and the maximum width of the pixel is L ₂ , then L ₁ × n ≧ L ₂ [where n is 0.1 or more and 3 or less Represents a number. And L ₂ is 100 μm or less.
(2) The light emitting device according to (1), wherein n represents a number of 0.1 or more and 2 or less.
(3) The light emitting device according to (1) or (2), wherein L ₂ is less than 100 μm.
(4) The light emitting device includes a light emitting element array in which the light emitting devices are linearly arranged, and the size of each pixel is larger in length in the direction perpendicular to the straight line than in length in the linear direction. The light emitting device according to any one of the above.
(5) Any one of (1) to (4), wherein a light receiving element that functions by receiving light emitted from the pixel is further disposed relative to the surface of the pixel, and operates as an image forming apparatus. The light emitting device according to one item.
(6) Operate as an image forming apparatus having a light condensing element having a function of condensing light emitted from the pixel on the light receiving element between the pixel and the light receiving element opposite to the pixel. The light-emitting device of description.
(7) The light emitting device according to (6), wherein the light condensing function of the light condensing element has an action of condensing light mainly in a plane perpendicular to the linear direction of the light emitting element array.
(8) The light emitting device according to any one of (1) to (7), wherein at least one of the organic substances included in the light emitting layer is a phosphorescent compound.
(9) Any one of (1) to (8), wherein at least one of the organic substances contained in the light-emitting layer is a polymer compound including one or more repeating units represented by the formula (1). The light emitting device according to 1.
-Ar _1- (1)
[Ar ₁ represents a group selected from the group consisting of an arylene group, a divalent heterocyclic compound group, and a divalent aromatic amine group. ]
(10) The light emitting device according to any one of (1) to (9), wherein at least one of organic substances included in the light emitting layer is a compound having fluorescence.
(11) In the method for manufacturing a light-emitting device according to any one of (1) to (10), by applying a light-emitting layer containing the organic substance on or above a substrate with a solution containing a light-emitting material. The said manufacturing method including forming.

A light-emitting device of the present invention includes an anode and a cathode, and a light-emitting layer containing at least one organic substance sandwiched between them, and includes two or more pixels each composed of an element that emits light by passing a current between the electrodes. (FIG. 1). All the pixels are formed on or above the same substrate.
The substrate is a member having a surface on which a pixel composed of an organic EL element used in the light-emitting portion of the light-emitting device of the present invention can be formed, as long as the surface is flat in a region larger than the pixel size. . A material capable of forming an organic EL element serving as a pixel, such as glass, plastic, Si, or metal, can be used. Examples of the shape include a plate shape and a rod shape. In the case of a plate shape, the shape may be flat or curved. Specific examples of the substrate include a glass plate, a plastic plate, a plastic film, a Si wafer, and a metal foil.

Here, a pixel is a minimum unit for forming an image. In the light emitting device of the present invention, an applied voltage (or current) for light emission can be controlled independently (for example, ON / OFF control). It refers to the portion of the light emitting element.
There are two or more pixels, and the arrangement thereof may be a straight line, or a plurality of columns may be arranged in parallel.
All pixels are on or above the same substrate. Here, “the pixel is above the substrate” means that another layer may exist between the organic EL element serving as the pixel and the substrate within a range that does not hinder heat conduction.

  In the light emitting device, at least one of the electrodes of each pixel is independently connected to the drive circuit for each pixel, and the applied voltage (or current) can be controlled independently (for example, ON / OFF control). (FIG. 2). The drive circuit has a function of switching between an energized state and a non-energized state, and may have only a simple ON / OFF switch function, but may be capable of switching voltage (or current) in multiple stages. The waveform of the voltage (or current) to be applied can be appropriately selected from a rectangular wave, a triangular wave, a sine wave, a pulse wave having an arbitrary shape, and the like.

Further, when the minimum value of the interval between adjacent pixels in each pixel is L ₁ and the maximum width of the pixel is L ₂ , L ₁ × n ≧ L ₂ [where n is a number from 0.1 to 3 To express. (FIG. 3). Here, the minimum value of the distance between adjacent pixels refers to the minimum value among the distances between adjacent pixels. In addition, the maximum width of the pixel indicates the length of the longer side in the case of a rectangle, the diameter in the case of a circle, and the length of the largest possible portion in other shapes.

Since the pixel pitch (periphery) is a factor that directly determines the resolution, it is determined at the stage of device design. A light-emitting device with higher luminance is required under the limitation of the pixel pitch. However, the organic EL element has a property that the lifetime is shortened when driven at high luminance. Selection is required.
The above conditional expression is a condition that distance L ₁ between pixels is equal to or greater than a value of 1 n of the pixel size L _2. When the value of n is large, the interval between the pixels can be reduced. The ratio of the area occupied by the pixels on or above the substrate is increased, and the amount of light per unit area is increased, but the generated heat is released. It becomes difficult. In addition, if n is small, it is advantageous for heat dissipation, but since the amount of light is small, a light-sensitive part with higher sensitivity is required, or the resolution of an image to be formed is low. However, the resolution can be substantially increased by arranging a plurality of pixel rows in parallel.
The range of n is a number of 0.1 or more and 3 or less, preferably a number of 0.1 or more and 2.5 or less, more preferably a number of 0.1 or more and 2 or less, and further preferably 0.3 or more and 2 or less. Is a number. It is preferable that the pixel interval is regularly constant.
The value of n in the above conditional expression can be appropriately changed according to the use of the light emitting device. For example, in applications such as a scanner, a value of n is usually selected from the range of 0.1 ≦ n <1, and in this case, L ₁ > L ₂ is always satisfied. For example, in applications such as copying machines and printers, the value of n is normally selected from the range of 1 ≦ n ≦ 3.

Further, if the pixel size is large, it is disadvantageous for heat dissipation during light emission, but if the pixel is too small, a sufficient amount of light can be output. Therefore, the maximum width of the pixel is 100 μm or less, preferably less than 100 μm, more preferably 10 μm or more and 50 μm or less.
In order to form or record an image, it is necessary to dispose an element that receives light emitted from the pixel and functions in relation to the surface of the pixel of the light emitting unit. In the electrophotographic system, by arranging a photosensitive drum or the like, an image can be formed depending on the presence or absence of surface charge, and printing can be performed using toner. It is also possible to directly convert to electronic information by receiving light from the pixel with a light receiving element such as a CCD.

The light emitting device of the present invention is preferably used at an average light emission luminance of 5,000 cd / m ² or more during pixel light emission. For normal display applications, the light emitting device of the present invention is often used with a lower average light emission luminance. However, the light emitting device of the present invention does not assume a usage method for direct viewing with the naked eye, and appropriately emits light when necessary with high luminance. This is very important.
As one embodiment of the light-emitting device, (1) a light-receiving element that functions by receiving light emitted from the pixel relative to the surface of the pixel is further arranged to operate as an image forming apparatus. And (2) an apparatus that operates as an image forming apparatus having a function of condensing light emitted from the pixel on the light receiving element between the pixel and the light receiving element opposed thereto.
As shown in FIG. 7, a pixel forming apparatus comprising a light emitting element array in which light emitting elements are arranged in a straight line, a light receiving device such as a photosensitive drum, and a light condensing element located between them and having a light condensing function. In this case, the luminance and lifetime problems can be solved by selecting the shape of the light emitting element in addition to the layout of the light emitting element described above. That is, when an element whose light collecting function by the light collecting element is mainly expressed in a plane perpendicular to the linear direction of the light emitting element array is used, the light from the rectangular light emitting part is condensed and is collected on the surface of the light receiving element. Since it can be circular or nearly square, light can be emitted in a larger area than in the case of a square light-emitting element, and higher light intensity can be used on the surface of the light-receiving portion (FIG. 8).
As the shape of the light emitting element, the size of each pixel of the light emitting element array in which the light emitting elements are arranged in a straight line has a length (T2) in a direction perpendicular to the linear direction rather than a length (T1) in the linear direction. A larger shape is preferred (T1 <T2) (FIG. 4). The ratio of T2 and T1 depends on the light condensing function of the lens, but the preferred range is approximately 1 or more and 10 or less.

  In order to perform image formation at a sufficiently high speed, for example, it is necessary to switch on / off of light emission at a sufficiently high speed. If the switching is slow or the OFF level is not sufficiently low due to afterglow, the image becomes unclear. It is preferable that ON / OFF switching can be performed in 100 μsec or less.

  The light emitting device of the present invention preferably has at least one peak in the visible region in the emission spectrum. It can be selected as appropriate in relation to the sensitivity of the light receiving unit, but if the emission spectrum is shifted to the short wavelength side, the drive voltage tends to be high, and if it is shifted to the long wavelength side, the luminous efficiency Tends to be low, which is not preferable.

  Next, the organic EL element used for the light emitting part of the light emitting device of the present invention will be described. The structure of the organic EL device of the present invention has a light emitting layer between electrodes composed of a pair of an anode and a cathode, at least one of which is transparent or translucent, and an organic substance (low molecule and / or polymer) emits light. Included in the layer.

In the organic EL element, examples of the layer other than the cathode, the anode, and the light emitting layer include those provided between the cathode and the light emitting layer and those provided between the anode and the light emitting layer.
Examples of the material provided between the cathode and the light emitting layer include an electron injection layer, an electron transport layer, and a hole blocking layer.
For example, when only one layer is provided between the cathode and the light emitting layer, it is an electron injection layer, and when two or more layers are provided between the cathode and the light emitting layer, the layer in contact with the cathode is the electron injection layer, and the other layers Is called an electron transport layer.

  The electron injection layer is a layer having a function of improving electron injection efficiency from the cathode, and the electron transport layer is a layer having a function of improving electron injection efficiency from the electron injection layer or the electron transport layer closer to the cathode. .

When the electron injection layer or the electron transport layer has a function of blocking hole transport, these layers may be referred to as a hole blocking layer.
Having the function of blocking hole transport makes it possible, for example, to produce an element that allows only hole current to flow, and confirm the blocking effect by reducing the current value.

Examples of the material provided between the anode and the light emitting layer include a hole injection layer, a hole transport layer, and an electron blocking layer.
When only one layer is provided between the anode and the light-emitting layer, it is a hole injection layer. When two or more layers are provided between the anode and the light-emitting layer, the layer in contact with the anode is the hole injection layer. The layer is referred to as a hole transport layer. The hole injection layer is a layer that has the function of improving the hole injection efficiency from the cathode, and the hole transport layer improves the hole injection efficiency from the hole injection layer or the hole transport layer closer to the anode. It is a layer having the function of In addition, when the hole injection layer or the hole transport layer has a function of blocking electron transport, these layers may be referred to as an electron block layer.
Having the function of blocking electron transport makes it possible, for example, to manufacture an element that allows only electron current to flow and to confirm the blocking effect by reducing the current value.

The organic EL element used in the light emitting part of the light emitting device of the present invention includes an organic EL element in which an electron transport layer is provided between the cathode and the light emitting layer, and a hole transport layer between the anode and the light emitting layer. And an organic EL element in which an electron transport layer is provided between the cathode and the light emitting layer and a hole transport layer is provided between the anode and the light emitting layer.
For example, the following structures a) to d) are specifically exemplified.
a) Anode / light emitting layer / cathode b) Anode / hole transport layer / light emitting layer / cathode c) Anode / light emitting layer / electron transport layer / cathode d) Anode / hole transport layer / light emitting layer / electron transport layer / cathode (Here, / indicates that each layer is laminated adjacently. The same shall apply hereinafter.)

Here, the light emitting layer is a layer having a function of emitting light, the hole transporting layer is a layer having a function of transporting holes, and the electron transporting layer is a layer having a function of transporting electrons. It is. The electron transport layer and the hole transport layer are collectively referred to as a charge transport layer.
Two or more light emitting layers, hole transport layers, and electron transport layers may be used independently.

  Further, among the charge transport layers provided adjacent to the electrodes, those having a function of improving the charge injection efficiency from the electrodes and having the effect of lowering the driving voltage of the element are particularly charge injection layers (hole injection layers). , An electron injection layer).

Further, in order to improve adhesion with the electrode and charge injection from the electrode, the charge injection layer or an insulating layer having a thickness of 2 nm or less may be provided adjacent to the electrode, and the adhesion at the interface may be improved. In order to prevent mixing, a thin buffer layer may be inserted at the interface between the charge transport layer and the light emitting layer.
The order and number of layers to be laminated, and the thickness of each layer can be appropriately used in consideration of light emission efficiency and element lifetime.

In the present invention, as an organic EL element provided with a charge injection layer (electron injection layer, hole injection layer), an organic EL element provided with a charge injection layer adjacent to the cathode, and a charge injection layer adjacent to the anode. The provided organic EL element is mentioned.
For example, the following structures e) to p) are specifically mentioned.
e) Anode / charge injection layer / light emitting layer / cathode f) Anode / light emitting layer / charge injection layer / cathode g) Anode / charge injection layer / light emitting layer / charge injection layer / cathode h) Anode / charge injection layer / hole Transport layer / light emitting layer / cathode i) anode / hole transport layer / light emitting layer / charge injection layer / cathode j) anode / charge injection layer / hole transport layer / light emitting layer / charge injection layer / cathode k) anode / charge Injection layer / light emitting layer / charge transport layer / cathode l) anode / light emitting layer / electron transport layer / charge injection layer / cathode m) anode / charge injection layer / light emitting layer / electron transport layer / charge injection layer / cathode n) anode / Charge injection layer / hole transport layer / light emitting layer / charge transport layer / cathode o) anode / hole transport layer / light emitting layer / electron transport layer / charge injection layer / cathode p) anode / charge injection layer / hole transport Layer / light emitting layer / electron transport layer / charge injection layer / cathode

  Specific examples of the charge injection layer include a layer containing a conductive polymer, an anode and a hole transport layer provided between the anode material and the hole transport material included in the hole transport layer. A layer containing a material having an ionization potential of a value, a layer provided between a cathode and an electron transport layer, and a layer containing a material having an electron affinity of an intermediate value between the cathode material and the electron transport material contained in the electron transport layer, etc. Is exemplified.

When the charge injection layer is a layer containing a conductive polymer, the electrical conductivity of the conductive polymer is preferably 10 ⁻⁵ S / cm or more and 10 ³ S / cm or less. in order to reduce the current, more preferably less 10 ^-5 S / cm or more and 10 ² S / cm, more preferably less 10 ^-5 S / cm or more and 10 ¹ S / cm.
Usually, in order to set the electric conductivity of the conductive polymer to 10 ⁻⁵ S / cm or more and 10 ³ S / cm or less, the conductive polymer is doped with an appropriate amount of ions.

The type of ions to be doped is an anion for the hole injection layer and a cation for the electron injection layer. Examples of anions include polystyrene sulfonate ions, alkylbenzene sulfonate ions, camphor sulfonate ions, and examples of cations include lithium ions, sodium ions, potassium ions, tetrabutylammonium ions, and the like.
The thickness of the charge injection layer is, for example, 1 nm to 100 nm, and preferably 2 nm to 50 nm.

  The material used for the charge injection layer may be appropriately selected in relation to the material of the electrode and the adjacent layer. Polyaniline and derivatives thereof, polythiophene and derivatives thereof, polypyrrole and derivatives thereof, polyphenylene vinylene and derivatives thereof, polythienylene vinylene And derivatives thereof, polyquinoline and derivatives thereof, polyquinoxaline and derivatives thereof, conductive polymers such as polymers containing an aromatic amine structure in the main chain or side chain, metal phthalocyanines (such as copper phthalocyanine), and carbon .

  An insulating layer having a thickness of 2 nm or less has a function of facilitating charge injection. Examples of the material for the insulating layer include metal fluorides, metal oxides, and organic insulating materials. As an organic EL element having an insulating layer having a thickness of 2 nm or less, an organic EL element having an insulating layer having a thickness of 2 nm or less adjacent to the cathode and an insulating layer having a thickness of 2 nm or less adjacent to the anode were provided. An organic EL element is mentioned.

Specific examples include the following structures q) to ab).
q) Anode / insulating layer with a thickness of 2 nm or less / light emitting layer / cathode r) Anode / light emitting layer / insulating layer with a thickness of 2 nm or less / cathode s) Anode / insulating layer with a thickness of 2 nm or less / light emitting layer / film thickness 2 nm Insulating layer / cathode t) Anode / insulating layer with a thickness of 2 nm or less / hole transport layer / light emitting layer / cathode u) Anode / hole transporting layer / light emitting layer / insulating layer with a thickness of 2 nm or less / cathode v) Anode / insulating layer with a thickness of 2 nm or less / hole transport layer / light emitting layer / insulating layer with a thickness of 2 nm or less / cathode w) anode / insulating layer with a thickness of 2 nm or less / light emitting layer / electron transport layer / cathode x) anode / Light emitting layer / electron transport layer / insulating layer with a thickness of 2 nm or less / cathode y) anode / insulating layer with a thickness of 2 nm or less / light emitting layer / electron transport layer / insulating layer with a thickness of 2 nm or less / cathode z) anode / film Insulating layer with a thickness of 2 nm or less / hole transport layer / light emitting layer / electron transport layer / cathode aa) anode / hole transport layer / light emitting layer / electron transport Layer / thickness 2nm or less of the insulating layer / cathode ab) anode / thickness 2nm or less of the insulating layer / hole transport layer / light emitting layer / electron transporting layer / thickness 2nm or less of the insulating layer / cathode

  When forming a film from a solution by using these organic solvent-soluble polymeric fluorescent substances in the production of an organic EL device, it is only necessary to remove the solvent by drying after applying this solution. The same technique can be applied even when a light emitting material is mixed, and it is very advantageous in manufacturing.

  As a film formation method from a solution, a spin coating method, a nozzle coating method, a casting method, a micro gravure coating method, a gravure coating method, a bar coating method, a roll coating method, a wire bar coating method, a dip coating method, a spray coating method, Coating methods such as a screen printing method, a flexographic printing method, an offset printing method, an ink jet printing method, a slit coating method, a capillary coating method, a dispenser method, and a micro dispenser method can be used. Printing methods such as a screen printing method, a freso printing method, an offset printing method, and an ink jet printing method are preferable in that pattern formation and multicolor coating are easy.

  When laminating a thin film using a solution, it is necessary that the layer in contact with the solution is not dissolved by the solution used. Therefore, when laminating from a solution by the above method, select an appropriate solvent type so that the solution used for thin film formation does not dissolve the layer in contact with the solution, or insolubilize the layer in contact with the solution by photocrosslinking or thermal crosslinking. An example is a method of laminating with a solution after the treatment.

The solution (ink composition) used in the printing method or the like only needs to contain at least one polymer fluorescent substance. In addition to the polymer fluorescent substance, a hole transport material, an electron transport material, a light emitting material, a solvent, Additives such as stabilizers may be included.
The viscosity of the ink composition varies depending on the printing method. However, when the ink composition passes through a discharge device such as an ink jet printing method, the viscosity is 1 at 25 ° C. in order to prevent clogging at the time of discharge and flight bending. It is preferably in the range of -20 mPa · s, more preferably in the range of 5-20 mPa · s, and even more preferably in the range of 7-20 mPa · s.

  The solution (ink composition) used in the printing method or the like may contain an additive for adjusting viscosity and / or surface tension in addition to the polymer compound. As the additive, a high molecular weight polymer compound (thickener) for increasing the viscosity, a poor solvent, a low molecular weight compound for decreasing the viscosity, a surfactant for decreasing the surface tension, and the like are appropriately combined. Use it.

  The high molecular weight polymer compound may be any compound that is soluble in the same solvent as the polymer compound of the present invention and does not inhibit light emission or charge transport. For example, high molecular weight polystyrene, polymethyl methacrylate, or a polymer compound of the present invention having a large molecular weight can be used. The weight average molecular weight in terms of polystyrene is preferably 500,000 or more, more preferably 1,000,000 or more.

  A poor solvent can also be used as a thickener. That is, the viscosity can be increased by adding a small amount of a poor solvent for the solid content in the solution. When a poor solvent is added for this purpose, the type and addition amount of the solvent may be selected as long as the solid content in the solution does not precipitate. Considering the stability during storage, the amount of the poor solvent is preferably 50 wt% or less, more preferably 30 wt% or less with respect to the entire solution.

  Further, the solution of the present invention may contain an antioxidant in order to improve storage stability. The antioxidant is not particularly limited as long as it is soluble in the same solvent as the polymeric fluorescent substance and does not inhibit light emission or charge transport, and examples thereof include phenol-based antioxidants and phosphorus-based antioxidants.

Although there is no restriction | limiting in particular as a solvent to be used, What can melt | dissolve or disperse | distribute uniformly materials other than the solvent which comprises an ink composition is preferable as this solvent chloroform, a methylene chloride, 1, 2- dichloroethane, 1, 1, 2- Chlorine solvents such as trichloroethane, chlorobenzene, o-dichlorobenzene, ether solvents such as tetrahydrofuran, dioxane, anisole, toluene, xylene, ethylbenzene, diethylbenzene, trimethylbenzene, n-propylbenzene, isopropylbenzene, n-butylbenzene, isobutyl Aromatic hydrocarbon solvents such as benzene, s-butylbenzene, ethoxybenzene, cyclohexylbenzene, 1-methylnaphthalene, cyclohexane, methylcyclohexane, n-pentane, n-hexane, n-heptane , N-octane, n-nonane, n-decane, bicyclohexyl, n-heptylcyclohexane, n-hexylcyclohexane, bicyclohexyl and other aliphatic hydrocarbon solvents, acetone, methyl ethyl ketone, cyclohexanone, benzophenone, acetophenone, cyclohexenylcyclohexanone , Ketone solvents such as 2-propylcyclohexanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-octanone, 2-nonanone, 2-decanone, dicyclohexylketone bicyclohexyl, ethyl acetate, butyl acetate, ethyl cellosolve acetate , Ester solvents such as methyl benzoate and phenyl acetate, ethylene glycol, ethylene glycol monobutyl ether, ethylene glycol monoethyl ether, ethylene glycol mono Polyhydric alcohols such as tilether, dimethoxyethane, propylene glycol, diethoxymethane, triethylene glycol monoethyl ether, glycerin, 1,2-hexanediol and derivatives thereof, alcohols such as methanol, ethanol, propanol, isopropanol, cyclohexanol Examples include solvents, sulfoxide solvents such as dimethyl sulfoxide, and amide solvents such as N-methyl-2-pyrrolidone and N, N-dimethylformamide.

These organic solvents can be used alone or in combination.
Of these, aromatic hydrocarbon solvents, aliphatic hydrocarbon solvents, ester solvents, ketone solvents are preferred from the viewpoint of solubility of polymer compounds, uniformity during film formation, viscosity characteristics, and the like. Toluene, xylene, ethylbenzene, diethylbenzene, trimethylbenzene, n-propylbenzene, isopropylbenzene, n-butylbenzene, isobutylbenzene, s-butylbenzene, anisole, ethoxybenzene, 1-methylnaphthalene, cyclohexane, cyclohexanone, cyclohexylbenzene, biphenyl Cyclohexyl, cyclohexenylcyclohexanone, n-heptylcyclohexane, n-hexylcyclohexane, 2-propylcyclohexanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-octanone, 2-nonanone, 2 Decanone, dicyclohexyl ketone, acetophenone, benzophenone more preferable.

The number of solvents in the solution is preferably two or more, more preferably two to three, and even more preferably two from the viewpoints of film formability and device characteristics.
When two kinds of solvents are contained in the solution, one of the solvents may be in a solid state at 25 ° C. From the viewpoint of film formability, one kind of solvent is preferably a solvent having a boiling point of 180 ° C. or higher, and more preferably 200 ° C. or higher. From the viewpoint of viscosity, it is preferable that 1 wt% or more of the aromatic polymer dissolves at 60 ° C. in one of the two solvents, and one solvent out of the two solvents contains 1 wt% at 25 ° C. The above aromatic polymer is preferably dissolved.

  When two or more kinds of solvents are contained in the solution, the solvent having the highest boiling point is preferably 40 to 90 wt% of the weight of the total solvent in the solution from the viewpoint of viscosity and film formability, and 50 to 90 wt%. % Is more preferable, and 65 to 85 wt% is more preferable.

  In the light emitting device of the present invention, the light emitting layer only needs to contain a known organic substance (organic light emitting material). The organic substance is a compound having fluorescence and / or phosphorescence at room temperature, and may be a low molecule or a polymer. A polymer compound in which at least one of the organic substances contained in the light emitting layer is a fluorescent compound, a phosphorescent compound, or one or more repeating units represented by the following formula (1) It is preferable that

Examples of the phosphorescent compound include iridium complexes and platinum complexes. As the low molecular weight compound having fluorescence, known compounds can be appropriately used.
When it is a high molecular compound, it is generally a compound having a polystyrene equivalent weight average molecular weight of 1000 or more. What consists of a repeating unit shown by following formula (1) is illustrated.
-Ar _1- Formula (1)
[Ar ₁ represents a group selected from the group consisting of an arylene group, a divalent heterocyclic compound group, and a divalent aromatic amine group. ]

Ar ₁ is a group selected from the group consisting of an arylene group, a divalent heterocyclic compound group, and a divalent aromatic amine group.

  An arylene group is an atomic group obtained by removing two hydrogen atoms from an aromatic hydrocarbon, having a condensed ring, two or more independent benzene rings or condensed rings bonded directly or via a group such as vinylene Also included. The arylene group may have a substituent. Carbon number of the part except the substituent in an arylene group is about 6-60 normally, Preferably it is 6-20. Moreover, the total carbon number including the substituent of an arylene group is about 6-100 normally. Examples of the arylene group include formulas 1A-1 to 1A-20 shown below.

In Ar ₁ represented by the above formulas 1A-1 to 1A-20, R represents a hydrogen atom, a bond, or a substituent. Any two of a plurality of Rs represent a bond, and any one or more of them represent a hydrogen atom. When a plurality of substituents represented by R are present, they may be the same or different. Ra represents a hydrogen atom or a substituent. When a plurality of substituents represented by Ra are present, they may be the same or different. When two Ras exist on the same atom, they may be combined to form an oxo group or a thioxo group, or may be bonded to each other to form a ring.
In addition, the substituent represented by R is a 5- to 7-membered aliphatic ring which may include heteroatoms such as an oxygen atom, a sulfur atom and a nitrogen atom among the substituents on adjacent atoms, Alternatively, a 5- to 7-membered aromatic ring may be formed.

Among the above-mentioned formulas 1A-1 to 1A-20, the arylene group represented by Ar ₁ includes a phenylene group (formula 1A-1), a naphthalene-diyl group (formula 1A-2), an anthracene-diyl group (1A- 3), dihydrophenanthrene-diyl group (formula 1A-10), fluorene-diyl group (formula 1A-13), indenonaphthalene-diyl group (formula 1A-14), biphenylene group (formula 1A-15), terphenylene Group (formula 1A-16 to 1A-18) is preferred, phenylene group (formula 1A-1), naphthalene-diyl group (formula 1A-2), dihydrophenanthrene-diyl group (formula 1A-10), fluorene-diyl group (Formula 1A-13), indenonaphthalene-diyl group (Formula 1A-14), biphenylene group (Formula 1A-15), terphenylene group (Formula 1A-16 to 1A-18) Are more preferable, and among them, a phenylene group (formula 1A-1), a naphthalene-diyl group (formula 1A-2), a fluorene-diyl group (formula 1A-13), and an indenonaphthalene-diyl group (formula 1A-14). Further preferred.

  A divalent heterocyclic compound group is a remaining atomic group obtained by removing two hydrogen atoms from a heterocyclic compound, and has a condensed ring, an independent monocyclic heterocyclic compound or two or more condensed rings directly. Or the thing couple | bonded through groups, such as vinylene, is also contained. In addition, a combination of a heterocyclic compound and an aromatic hydrocarbon is also included. The divalent heterocyclic compound group may have a substituent. Carbon number of the part except the substituent in a bivalent heterocyclic compound group is about 4-60 normally, Preferably it is 2-20. Moreover, the total carbon number including the substituent of a bivalent heterocyclic compound group is about 2-100 normally. Here, a heterocyclic compound is an organic compound having a cyclic structure in which the elements constituting the ring include not only carbon atoms but also heteroatoms such as oxygen, sulfur, nitrogen, phosphorus, and boron in the ring. Say. Examples of the divalent heterocyclic compound group include formulas 2A-1 to 2A-53 and 2A-101 to 2A-116 shown below.

In Ar ₁ represented by the formula 2A-1-2A-53 and 2A-101~2A-116,, R represents a hydrogen atom, bond or a substituent. Any two of a plurality of Rs represent a bond, and any one or more of them represent a hydrogen atom. When a plurality of substituents represented by R are present, they may be the same or different. Ra represents a hydrogen atom or a substituent. When a plurality of substituents represented by Ra are present, they may be the same or different. When two Ras exist on the same atom, they may be combined to form an oxo group or a thioxo group, or may be bonded to each other to form a ring.

  The substituent represented by R is a substituent on adjacent atoms, a 5- to 7-membered aliphatic ring containing a hetero atom such as an oxygen atom, a sulfur atom, or a nitrogen atom, or an oxygen atom A 5- to 7-membered aromatic ring which may contain a heteroatom such as sulfur atom or nitrogen atom may be formed.

Examples of the divalent heterocyclic compound group represented by Ar ₁ include pyridine-diyl group (formula 2A-1), quinoline-of the above formulas 2A-1 to 2A-53 and 2A-101 to 2A-116. Diyl group (formula 2A-6), isoquinoline-diyl group (formula 2A-7), quinoxaline-diyl group (formula 2A-8), phenanthroline-diyl group (2A-18), thiophene-diyl group (formula 2A-22) ), Imidazole-diyl group (2A-24), oxazole-diyl group (formula 2A-26), thiazole-diyl group (2A-27), nitrogen, sulfur, oxygen or selenium as a hetero atom, Fluorene-like skeleton containing a ringed 5-membered heterocyclic compound group (formula 2A-30 to 2A-32 and 2A-34 to 2A-40), silicon, nitrogen, oxygen, or sulfur as a hetero atom Having heterocyclic compound groups (formulas 2A-41 to 2A-44 and 2A-46 to 2A-47), heterocyclic compound groups having a condensed ring structure represented by formulas 2A-48 to 2A-53, and diazaphenylene groups (Formula 2A-101), a compound group in which a phenyl group or a thienyl group is bonded to the 2,5-position of a 5-membered heterocyclic compound group containing nitrogen, oxygen, or sulfur as a hetero atom (Formula 2A-103, 2A- 105-2A-106, and 2A-108-2A-110), containing a nitrogen atom, oxygen, or sulfur as a hetero atom, and a phenyl group or a thienyl group bonded to a 5-membered heterocyclic compound group condensed with a benzene ring Compound groups (formula 2A-111-2A-116) are preferred, pyridine-diyl group (formula 2A-1), quinoline-diyl group (formula 2A-6), isoquinoline-diyl group (formula 2A-7), quinoxa A heterocyclic compound group having a fluorene-like skeleton containing a phosphorus-diyl group (formula 2A-8), a phenanthroline-diyl group (2A-18), silicon, nitrogen, oxygen, or sulfur as a hetero atom (formulas 2A-41 to 2A -44, and 2A-46 to 2A-47), a heterocyclic compound group having a condensed ring structure represented by formulas 2A-48 to 2A-53, a diazaphenylene group (formula 2A-101), nitrogen as a hetero atom, Compound groups (formula 2A-103, 2A-105 to 2A-106, and 2A-108 to 2A-110) in which a phenyl group is bonded to the 2,5-position of a 5-membered ring heterocyclic compound group containing oxygen or sulfur Further, a compound group (formula 2A-111-2A-116) containing nitrogen, oxygen, or sulfur as a heteroatom and having a phenyl group bonded to a 5-membered heterocyclic compound group condensed with a benzene ring is more preferable. , Heterocyclic groups having a fluorene-like skeleton containing silicon, nitrogen, oxygen, or sulfur as a hetero atom (formulas 2A-41 to 2A-44 and 2A-46 to 2A-47), formulas 2A-48 to 2A-53 A compound group (formula 2A-103, wherein a phenyl group is bonded to the 2,5-position of a heterocyclic group having a condensed ring structure represented by the above, a 5-membered heterocyclic compound group containing nitrogen, oxygen, or sulfur as a hetero atom; 2A-105 to 2A-106, and 2A-108 to 2A-110), a compound containing nitrogen, oxygen, or sulfur as a hetero atom, and a phenyl group bonded to a 5-membered heterocyclic compound group condensed with a benzene ring More preferred are groups (Formulas 2A-111-2A-116).

  The divalent aromatic amine group is a remaining atomic group obtained by removing two hydrogen atoms from an aromatic amine. The divalent aromatic amine group may have a substituent. The carbon number of the part except the substituent in a bivalent aromatic amine group is about 4-60 normally. As a bivalent aromatic amine group, group shown by the following general formula (1-2) is mentioned, for example.

(In the formula, Ar ³ , Ar ⁴ , Ar ⁵ and Ar ⁶ each independently represent an arylene group or a divalent heterocyclic group. Ar ⁷ , Ar ⁸ and Ar ⁹ each independently represent an aryl group or a monovalent group. Ar ³ , Ar ⁴ , Ar ⁵ , Ar ⁶ , Ar ⁷ , Ar ⁸ and Ar ⁹ may have a substituent, and r and rr each independently represent 0 or 1 .)

  Specific examples of the divalent aromatic amine group include groups represented by the following formulas 3A-1 to 3A-8.

In Ar ₁ represented by the above formulas 3A-1 to 3A-8, R represents a hydrogen atom, a bond, or a substituent. Any two of a plurality of Rs represent a bond, and any one or more of them represent a hydrogen atom. When a plurality of substituents represented by R are present, they may be the same or different.
Examples of the divalent aromatic amine group represented by Ar _1, of the formula 3A-. 1-3A-8, divalent aromatic amine group represented by the formula 3A-1~3A-4 are preferred, wherein The divalent aromatic amine group represented by 3A-1 to 3A-3 is more preferred, and the groups represented by Formulas 3A-2 and 3A-3 are more preferred.

The substituent represented by R is a substituent on adjacent atoms, a 5- to 7-membered aliphatic ring containing a hetero atom such as an oxygen atom, a sulfur atom, or a nitrogen atom, or an oxygen atom A 5- to 7-membered aromatic ring which may contain a heteroatom such as sulfur atom or nitrogen atom may be formed.
Examples of the substituent represented by R or Ra include an alkyl group, an aryl group, an aralkyl group, a monovalent heterocyclic group, an arylalkenyl group, an arylalkynyl group, an alkoxy group, an aryloxy group, an aralkyloxy group, an alkylthio group, Examples include an arylthio group, an aralkylthio group, a substituted amino group, a substituted silyl group, a sulfonic acid group, a phosphono group, a cyano group, and a nitro group.

The alkyl group represented by R or Ra may be linear, branched or cyclic, and usually has about 1 to 20 carbon atoms, preferably 3 to 20 carbon atoms. Specific examples thereof include methyl group, ethyl group Group, propyl group, isopropyl group, n-butyl group, isobutyl group, s-butyl group, t-butyl group, pentyl group, isopentyl group, hexyl group, cyclohexyl group, heptyl group, octyl group, 2-ethylhexyl group, nonyl Group, decyl group, 3,7-dimethyloctyl group, dodecyl group, octadecyl group and the like.
From the viewpoint of solubility in organic solvents and ease of synthesis, methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, s-butyl group, t-butyl group, pentyl group , Isopentyl group, hexyl group, cyclohexyl group, heptyl group, cyclohexylmethyl group, octyl group, 2-ethylhexyl group, 2-cyclohexylethyl group, nonyl group, decyl group, 3,7-dimethyloctyl group, and dodecyl group are preferable. , Methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, s-butyl group, t-butyl group, pentyl group, isopentyl group, hexyl group, cyclohexyl group, heptyl group, octyl group, 2-ethylhexyl Group, nonyl group, decyl group, and 3,7-dimethyloctyl group are more preferable, propyl group Isopropyl, butyl, isobutyl, s-butyl, t-butyl, pentyl, isopentyl, hexyl, cyclohexyl, heptyl, octyl, 2-ethylhexyl, nonyl, decyl, and 3 More preferred is a 7,7-dimethyloctyl group.

The aryl group is an atomic group obtained by removing one hydrogen atom on an aromatic ring from an aromatic hydrocarbon, and includes those having a condensed ring. The aryl group usually has about 6 to 60 carbon atoms, preferably 7 to 48 carbon atoms. Specific examples thereof include a phenyl group and a C _{1 to} C ₁₂ alkylphenyl group (C _{1 to} C ₁₂ have 1 to The same applies to the following.), 1-naphthyl group, 2-naphthyl group, 1-anthracenyl group, 2-anthracenyl group, 9-anthracenyl group and the like.
From the viewpoints of solubility in an organic solvent and ease of synthesis, a C _{1 to} C ₁₂ alkylphenyl group is preferred.

C ₁ -C ₁₂ specifically alkylphenyl group include a methylphenyl group, ethylphenyl group, dimethylphenyl group, dimethyl -t- butylphenyl group, propylphenyl group, mesityl group, methylethylphenyl group, isopropylphenyl radical, n -Butylphenyl group, isobutylphenyl group, s-butylphenyl group, t-butylphenyl group, pentylphenyl group, isopentylphenyl group, hexylphenyl group, heptylphenyl group, octylphenyl group, nonylphenyl group, decylphenyl group, 3,7-dimethyloctylphenyl group, dodecylphenyl group and the like are exemplified, and dimethylphenyl group, dimethyl-t-butylphenyl group, propylphenyl group, mesityl group, methylethylphenyl group, isopropylphenyl group, n-butylphenyl group ,I Butylphenyl group, s-butylphenyl group, t-butylphenyl group, pentylphenyl group, isopentylphenyl group, hexylphenyl group, heptylphenyl group, octylphenyl group, nonylphenyl group, decylphenyl group, 3,7-dimethyl Octylphenyl and dodecylphenyl groups are preferred.

Aralkyl groups, usually about 7 to 60 carbon atoms, preferably 7 to 48, and examples thereof include phenyl -C ₁ -C ₁₂ alkyl group, C ₁ -C ₁₂ alkylphenyl -C ₁ -C ₁₂ Examples include alkyl groups, 1-naphthyl-C ₁ -C ₁₂ alkyl groups, 2-naphthyl-C ₁ -C ₁₂ alkyl groups, and the like.
Solubility in organic solvents, from the viewpoint of easiness of synthesis, C ₁ -C ₁₂ alkylphenyl -C ₁ -C ₁₂ alkyl group are preferable.

The monovalent heterocyclic compound group is a remaining atomic group obtained by removing one hydrogen atom from a heterocyclic compound, and usually has about 4 to 60 carbon atoms, preferably 4 to 20 carbon atoms. The carbon number of the heterocyclic compound group does not include the carbon number of the substituent. Here, the heterocyclic compound is an organic compound having a cyclic structure in which the elements constituting the ring include not only carbon atoms but also hetero atoms such as oxygen, sulfur, nitrogen, phosphorus, boron, etc. in the ring. Say. Specifically, a thienyl group, C ₁ -C ₁₂ alkyl thienyl group, a pyrrolyl group, a furyl group, a pyridyl group, C ₁ -C ₁₂ alkyl pyridyl group, piperidyl group, quinolyl group, isoquinolyl group and the like.
Solubility in organic solvents, from the viewpoint of easiness of synthesis and the like, a thienyl group, C ₁ -C ₁₂ alkyl thienyl group, a pyridyl group, and C ₁ -C ₁₂ alkyl pyridyl group are preferable.

The arylalkenyl group has a carbon number of usually about 8 to 60, specifically, a phenyl -C ₂ -C ₁₂ alkenyl group, C ₁ -C ₁₂ alkylphenyl -C ₂ -C ₁₂ alkenyl group, 1- Examples include a naphthyl-C ₂ -C ₁₂ alkenyl group, a 2-naphthyl-C ₂ -C ₁₂ alkenyl group, and the like.
Solubility in organic solvents, from the viewpoint of easiness of synthesis, C ₁ -C ₁₂ alkylphenyl -C ₂ -C ₁₂ alkenyl groups are preferred.

The arylalkynyl group has a carbon number of usually about 8 to 60, specifically, a phenyl -C ₂ -C ₁₂ alkynyl group, C ₁ -C ₁₂ alkylphenyl -C ₂ -C ₁₂ alkynyl group, 1- Examples thereof include a naphthyl-C ₂ -C ₁₂ alkynyl group and a 2-naphthyl-C ₂ -C ₁₂ alkynyl group.
Solubility in organic solvents, from the viewpoint of easiness of synthesis, C ₁ -C ₁₂ alkylphenyl -C ₂ -C ₁₂ alkynyl group are preferable.

The alkoxy group may be linear, branched or cyclic, and usually has about 1 to 20 carbon atoms, preferably 3 to 20 carbon atoms. Specific examples thereof include a methoxy group, an ethoxy group, and a propyloxy group. , Isopropyloxy group, n-butoxy group, isobutoxy group, t-butoxy group, pentyloxy group, hexyloxy group, cyclohexyloxy group, heptyloxy group, octyloxy group, 2-ethylhexyloxy group, nonyloxy group, decyloxy group, 3,7-dimethyloctyloxy group, dodecyloxy group and the like can be mentioned.
From the viewpoints of solubility in an organic solvent and ease of synthesis, a pentyloxy group, a hexyloxy group, an octyloxy group, a 2-ethylhexyloxy group, a decyloxy group, and a 3,7-dimethyloctyloxy group are preferable. .

The aryloxy group usually has about 6 to 60 carbon atoms, preferably 7 to 48. Specific examples thereof include a phenoxy group, a C _{1 to} C ₁₂ alkylphenoxy group, a 1-naphthyloxy group, and 2-naphthyl. An oxy group etc. are illustrated.
From the viewpoints of solubility in an organic solvent and ease of synthesis, a C _{1 to} C ₁₂ alkylphenoxy group is preferable.
Specific examples of the C ₁ -C ₁₂ alkylphenoxy group include methylphenoxy group, ethylphenoxy group, dimethylphenoxy group, propylphenoxy group, 1,3,5-trimethylphenoxy group, methylethylphenoxy group, isopropylphenoxy group, n- Examples include butylphenoxy, isobutylphenoxy, t-butylphenoxy, pentylphenoxy, isopentylphenoxy, hexylphenoxy, heptylphenoxy, octylphenoxy, nonylphenoxy, decylphenoxy, dodecylphenoxy The

The aralkyloxy group usually has about 7 to 60 carbon atoms, preferably 7 to 48 carbon atoms. Specific examples thereof include a phenylmethoxy group, a phenylethoxy group, a phenyl-n-butoxy group, and a phenylpentyloxy group. , phenylhexyloxy group, phenyl heptyloxy group, phenyl -C ₁ -C ₁₂ alkoxy groups such as a phenyl octyl group, C ₁ -C ₁₂ alkylphenyl -C ₁ -C ₁₂ alkoxy groups, 1-naphthyl -C ₁ ~ C ₁₂ alkoxy groups, 2-naphthyl -C ₁ -C ₁₂ alkoxy groups.
Solubility in organic solvents, from the viewpoint of easiness of synthesis, C ₁ -C ₁₂ alkylphenyl -C ₁ -C ₁₂ alkoxy group are preferable.

The alkylthio group may be linear, branched or cyclic, and usually has about 1 to 20 carbon atoms, preferably 3 to 20 carbon atoms. Specific examples thereof include a methylthio group, an ethylthio group, a propylthio group, Isopropylthio group, n-butylthio group, isobutylthio group, t-butylthio group, pentylthio group, hexylthio group, cyclohexylthio group, heptylthio group, octylthio group, 2-ethylhexylthio group, nonylthio group, decylthio group, 3,7- Examples thereof include dimethyloctylthio group and dodecylthio group.
From the viewpoints of solubility in an organic solvent and ease of synthesis, a pentylthio group, a hexylthio group, an octylthio group, a 2-ethylhexylthio group, a decylthio group, and a 3,7-dimethyloctylthio group are preferable.

The arylthio group has a carbon number of usually about 3 to 60, and specific examples thereof include a phenylthio group, C ₁ -C ₁₂ alkyl phenylthio group, 1-naphthylthio group and 2-naphthylthio groups.
From the viewpoints of solubility in an organic solvent and ease of synthesis, a C _{1 to} C ₁₂ alkylphenylthio group is preferred.

The aralkylthio group usually has about 7 to 60 carbon atoms, preferably 7 to 48 carbon atoms. Specific examples thereof include a phenyl-C ₁ -C ₁₂ alkylthio group and a C ₁ -C ₁₂ alkylphenyl-C. ₁ -C ₁₂ alkylthio group, 1-naphthyl -C ₁ -C ₁₂ alkylthio group, 2-naphthyl -C ₁ -C ₁₂ alkylthio groups.
Solubility in organic solvents, from the viewpoint of easiness of synthesis, C ₁ -C ₁₂ alkylphenyl -C ₁ -C ₁₂ alkylthio group are preferable.

Examples of the substituted amino group include an amino group substituted with one or two groups selected from an alkyl group, an aryl group, an arylalkyl group, or a monovalent heterocyclic group, and usually has about 1 to 60 carbon atoms, Preferably it is C2-C48.
Specifically, methylamino group, dimethylamino group, ethylamino group, diethylamino group, propylamino group, dipropylamino group, isopropylamino group, diisopropylamino group, n-butylamino group, isobutylamino group, t-butyl Amino group, pentylamino group, hexylamino group, cyclohexylamino group, heptylamino group, octylamino group, 2-ethylhexylamino group, nonylamino group, decylamino group, 3,7-dimethyloctylamino group, dodecylamino group, cyclopentylamino group, cyclopentylamino group, cyclohexylamino group, dicyclohexylamino group, pyrrolidyl group, piperidyl group, diphenylamino group, (C ₁ -C ₁₂ alkylphenyl) amino group, di (C ₁ -C ₁₂ alkylphenyl) amino group, 1- Fuchiruamino group, 2-naphthylamino group, pyridylamino group, pyridazinylamino group, pyrimidylamino group, Pirajiruamino group, triazyl amino group, phenyl -C ₁ -C ₁₂ alkylamino group, C ₁ -C ₁₂ alkylphenyl -C ₁ -C ₁₂ alkylamino group, di (C ₁ -C ₁₂ alkylphenyl -C ₁ -C ₁₂ alkyl) amino groups, 1-naphthyl -C ₁ -C ₁₂ alkylamino group, 2-naphthyl -C ₁ -C ₁₂ Examples include alkylamino groups.
From the viewpoints of solubility in an organic solvent, ease of synthesis, and the like, disubstituted amino groups such as a dimethylamino group, a diethylamino group, a diphenylamino group, and a di (C _{1 to} C ₁₂ alkylphenyl) amino group are preferable. Diarylamino groups such as diphenylamino groups and di (C ₁ -C ₁₂ alkylphenyl) amino groups are more preferred.

Examples of the substituted silyl group include a silyl group substituted with 1, 2 or 3 groups selected from an alkyl group, an aryl group, an arylalkyl group or a monovalent heterocyclic group. The substituted silyl group usually has about 1 to 60 carbon atoms, preferably 3 to 48 carbon atoms.
Specifically, trimethylsilyl group, triethylsilyl group, tripropylsilyl group, triisopropylsilyl group, dimethylisopropylpropylsilyl group, diethylisopropylsilyl group, t-butylsilyldimethylsilyl group, pentyldimethylsilyl group, hexyldimethylsilyl group , Heptyldimethylsilyl group, octyldimethylsilyl group, 2-ethylhexyl-dimethylsilyl group, nonyldimethylsilyl group, decyldimethylsilyl group, 3,7-dimethyloctyl-dimethylsilyl group, dodecyldimethylsilyl group, phenyl-C _1- C ₁₂ alkylsilyl group, C ₁ -C ₁₂ alkylphenyl -C ₁ -C ₁₂ alkylsilyl group, 1-naphthyl -C ₁ -C ₁₂ alkylsilyl group, 2-naphthyl -C ₁ -C ₁₂ alkylsilyl group, phenyl -C ₁ -C ₁₂ alkyl dimethicone Silyl group, triphenyl silyl group, tri -p- methylphenyl silyl group, tribenzylsilyl group, diphenylmethylsilyl group, t- butyl diphenyl silyl group, dimethyl phenyl silyl groups.

  When the substituent represented by R or Ra includes an aryl group or a monovalent heterocyclic group, the hydrogen atom on the aryl group or monovalent heterocyclic group is an aryl group, an aralkyl group, or a monovalent group. Heterocyclic group, arylalkenyl group, arylalkynyl group, alkoxy group, aryloxy group, aralkyloxy group, alkylthio group, arylthio group, aralkylthio group, substituted amino group, substituted silyl group, sulfonic acid group, phosphono group, cyano It may be substituted with a group or a nitro group. Among them, aryl groups, aralkyl groups, monovalent heterocyclic groups, alkoxy groups, aryloxy groups, aralkyloxy groups, alkylthio groups, arylthio groups, aralkylthio groups, substituted amino groups, substituted silyl groups, sulfonic acid groups, phosphono groups, A cyano group and a nitro group are preferable, and an alkyl group, an aryl group, an aralkyl group, a monovalent heterocyclic group, an alkoxy group, an aryloxy group, an aralkyloxy group, an alkylthio group, an arylthio group, an aralkylthio group, and a substituted amino group Are more preferable, and an alkoxy group and an alkylthio group are more preferable.

Specifically, for example, C ₁ -C ₁₂ alkoxyphenyl group, C ₁ -C ₁₂ alkoxyphenyl-C ₁ -C ₁₂ alkyl group, C ₁ -C ₁₂ alkoxyphenyl-C ₂ -C ₁₂ alkenyl group, C ₁ -C ₁₂ alkoxyphenyl -C ₂ -C ₁₂ alkynyl groups, C ₁ -C ₁₂ alkoxyphenoxy groups, C ₁ -C ₁₂ alkoxyphenyl -C ₁ -C ₁₂ alkoxy groups, C ₁ -C ₁₂ alkoxyphenyl-thio groups, C ₁ -C ₁₂ alkoxyphenyl -C ₁ -C ₁₂ alkylthio group, C ₁ -C ₁₂ alkoxyphenyl amino group, di (C ₁ -C ₁₂ alkoxyphenyl) amino groups, C ₁ -C ₁₂ alkoxyphenyl -C ₁ -C ₁₂ alkylamino groups, di (C ₁ -C ₁₂ alkoxyphenyl -C ₁ -C ₁₂ alkyl) amino group, C ₁ -C such C ₁ -C ₁₂ alkoxyphenyl -C ₁ -C ₁₂ alkylsilyl group And a group having ₁₂ alkoxy substituent groups. Specific examples of C ₁ -C ₁₂ alkoxy include methoxy, ethoxy, propyloxy, isopropyloxy, n-butoxy, isobutoxy, s-butoxy, t-butoxy, pentyloxy, hexyloxy, cyclohexyloxy, heptyloxy, octyloxy , 2-ethylhexyloxy, nonyloxy, decyloxy, 3,7-dimethyloctyloxy, dodecyloxy and the like.

In addition, when the substituent represented by R or Ra includes an alkylene chain, any —CH ₂ — group in the alkylene chain includes a divalent heteroatom such as oxygen, sulfur, nitrogen, or a heteroatom. It may be substituted with a divalent group or a divalent group in which two or more of them are combined. Examples of the divalent group containing a divalent heteroatom and a hetero atom include groups represented by the following formulas X-1 to X-5 and X-7 to X-10. R ″ has the same meaning as R, and Ar represents a trivalent group in formulas (X-7) and (X-8) and a tetravalent group in formula (X-9).

  Examples of the divalent group in which two or more divalent groups containing a divalent hetero atom or a hetero atom are combined include groups represented by the following formulas XX-1 to XX-4. . R ″ has the same meaning as R.

  Among the above formulas X-1 to X-5, X-6 to X-10, and XX-1 to XX-4, formulas X-1, X-2, X-3, X-5, and X- 7 is preferred, the groups represented by formulas X-1 and X-2 are more preferred, and the group represented by formula (X-1) is more preferred. Specific examples include a methoxymethyloxy group and a 2-methoxyethyloxy group.

Examples of the substituent represented by R in the group represented by Ar ₁ include an alkyl group, aryl group, aralkyl group, monovalent heterocyclic group, alkoxy group, aryloxy group, aralkyloxy group, alkylthio group, arylthio group, aralkyl. Thio group, substituted amino group, substituted silyl group, sulfonic acid group, phosphono group, cyano group, and nitro group are preferred, alkyl group, aryl group, aralkyl group, monovalent heterocyclic group, alkoxy group, aryloxy group, Aralkyloxy groups, alkylthio groups, arylthio groups, aralkylthio groups, and substituted amino groups are more preferred, alkyl groups, alkoxy groups, and alkylthio groups are more preferred, and alkyl groups are particularly preferred.

The substituent represented by Ra in the group represented by Ar ₁ includes an alkyl group, aryl group, aralkyl group, monovalent heterocyclic group, alkoxy group, aryloxy group, aralkyloxy group, alkylthio group, arylthio group, aralkyl. A thio group, a substituted amino group, a substituted silyl group, an oxo group and a thioxo group are preferred, an alkyl group, an alkoxy group, an alkylthio group, an alkylsilyl group, an oxo group and a thioxo group are more preferred, and an alkyl group and an alkoxy group are preferred. More preferred is an alkyl group.

A homopolymer containing a single repeating unit may be used, but a copolymer containing a plurality of types of repeating units may also be used. In order to obtain a structure having functions of both light emission and charge transport as appropriate, it is preferable to use a copolymer.
The structure of the polymer compound may be random, block, graft, or a combination thereof. In the case of a type having a branch, a hyperbranch may be used instead of a simple branch.

Among these luminescent materials, those that are soluble in an organic solvent can be formed by a coating method, and are advantageous in terms of process and are preferable.
As the film thickness of the light emitting layer, the optimum value varies depending on the material to be used, and it may be selected so that the driving voltage and the light emission efficiency are appropriate values. More preferably, it is 5 nm-200 nm.

In the organic EL element used for the light emitting part of the light emitting device of the present invention, a polymer light emitting material can be used for the light emitting layer, but other light emitting materials may be used. In the organic EL element used for the light emitting portion of the light emitting device of the present invention, a light emitting layer containing a light emitting material may be laminated with a light emitting layer containing another light emitting material.
In addition, examples of the light-emitting material that can be used in the organic EL element used in the light-emitting portion of the light-emitting device of the present invention include known low-molecular compounds and triplet light-emitting complexes.

Examples of low molecular weight compounds include naphthalene derivatives, anthracene or derivatives thereof, perylene or derivatives thereof, polymethine-based, xanthene-based, coumarin-based, cyanine-based pigments, 8-hydroxyquinoline or metal complexes of derivatives thereof, aromatic amines, and the like. , Tetraphenylcyclopentadiene or a derivative thereof, or tetraphenylbutadiene or a derivative thereof can be used.
Specifically, for example, known ones such as those described in JP-A-57-51781 and 59-194393 can be used.

Examples of triplet light-emitting complexes include Ir (ppy) ₃ , Btp ₂ Ir (acac) having iridium as a central metal, PtOEP having platinum as a central metal, Eu (TTA) ₃ phen having a central metal as europium, and the like. Can be mentioned.

  Specific examples of the triplet light-emitting complex include Nature, (1998), 395, 151, Appl. Phys. Lett. (1999), 75 (1), 4, Proc. SPIE-Int. Soc. Opt. Eng. (2001), 4105 (Organic Light-Emitting Materials and Devices IV), 119, J. MoI. Am. Chem. Soc. , (2001), 123, 4304, Appl. Phys. Lett. , (1997), 71 (18), 2596, Syn. Met. , (1998), 94 (1), 103, Syn. Met. , (1999), 99 (2), 1361, Adv. Mater. , (1999), 11 (10), 852, Jpn. J. et al. Appl. Phys. 34, 1883 (1995).

As a method for forming a light emitting layer containing an organic substance, a method of applying a solution containing a light emitting material on or above a substrate, a vacuum deposition method, a transfer method, or the like can be used.
The light emitting device is preferably manufactured by a method including forming the light emitting layer containing the organic substance by applying a solution containing a light emitting material on or above the substrate.
As a method of applying a solution containing a light emitting material on or above a substrate, spin coating, nozzle coating, dip coating, ink jet, flexographic printing, gravure printing, slit coating, capillary coating, dispenser, microdispenser, etc. are applied. Can be used. In the case of a sublimable low-molecular compound, a vacuum deposition method can be used. Furthermore, a method of forming a light emitting layer only at a desired place by laser transfer or thermal transfer can be used.

  When the organic EL element used in the light-emitting portion of the light-emitting device of the present invention has a hole transport layer, the hole transport material used may be polyvinyl carbazole or a derivative thereof, polysilane or a derivative thereof, an aromatic group in a side chain or a main chain. A polysiloxane derivative having a group amine, a pyrazoline derivative, an arylamine derivative, a stilbene derivative, a triphenyldiamine derivative, polyaniline or a derivative thereof, polythiophene or a derivative thereof, polypyrrole or a derivative thereof, poly (p-phenylene vinylene) or a derivative thereof, or Examples include poly (2,5-thienylene vinylene) or derivatives thereof.

  Specifically, as the hole transport material, JP-A-63-70257, JP-A-63-175860, JP-A-2-135359, JP-A-2-135361, JP-A-2-209998, Examples described in JP-A-3-37992 and JP-A-3-152184 are exemplified.

  Among these, as a hole transport material used for the hole transport layer, polyvinyl carbazole or a derivative thereof, polysilane or a derivative thereof, a polysiloxane derivative having an aromatic amine compound group in a side chain or a main chain, polyaniline or a derivative thereof, Preferred is a polymer hole transport material such as polythiophene or a derivative thereof, poly (p-phenylene vinylene) or a derivative thereof, or poly (2,5-thienylene vinylene) or a derivative thereof, more preferably polyvinyl carbazole or a derivative thereof, Polysilane or a derivative thereof, or a polysiloxane derivative having an aromatic amine in the side chain or main chain. In the case of a low-molecular hole transport material, it is preferably used by being dispersed in a polymer binder.

  Polyvinylcarbazole or a derivative thereof is obtained, for example, from a vinyl monomer by cation polymerization or radical polymerization.

  Examples of the polysilane or derivatives thereof include compounds described in Chem. Rev. 89, 1359 (1989), GB 2300196 published specification, and the like. As the synthesis method, the methods described in these can be used, but the Kipping method is particularly preferably used.

  Since polysiloxane or a derivative thereof has almost no hole transporting property in the siloxane skeleton structure, those having the structure of the low molecular hole transporting material in the side chain or main chain are preferably used. Particularly, those having a hole transporting aromatic amine in the side chain or main chain are exemplified.

  Although there is no restriction | limiting in the film-forming method of a positive hole transport layer, In the low molecular hole transport material, the method by the film-forming from a mixed solution with a polymer binder is illustrated. In the case of a polymer hole transport material, a method of film formation from a solution is exemplified.

  The solvent used for film formation from a solution is not particularly limited as long as it can dissolve a hole transport material. Examples of the solvent include chlorine solvents such as chloroform, methylene chloride, and dichloroethane; ether solvents such as tetrahydrofuran; aromatic hydrocarbon solvents such as toluene and xylene; ketone solvents such as acetone and methyl ethyl ketone; ethyl acetate, butyl acetate, An ester solvent such as ethyl cellosolve acetate is exemplified.

  Examples of film formation methods from solution include spin coating from solution, nozzle coating, casting, micro gravure coating, gravure coating, bar coating, roll coating, wire bar coating, dip coating, and spray. Coating methods such as a coating method, a screen printing method, a flexographic printing method, an offset printing method, an ink jet printing method, a slit coating method, a capillary coating method, a dispenser method, and a microdispenser method can be used.

  As the polymer binder to be mixed, those not extremely disturbing charge transport are preferable, and those showing no strong absorption against visible light are suitably used. Examples of the polymer binder include polycarbonate, polyacrylate, polymethyl acrylate, polymethyl methacrylate, polystyrene, polyvinyl chloride, and polysiloxane.

  The film thickness of the hole transport layer differs depending on the material used, and may be selected so that the drive voltage and the light emission efficiency are appropriate. However, at least a thickness that does not cause pinholes is required. If it is too thick, the driving voltage of the element becomes high, which is not preferable. Therefore, the film thickness of the hole transport layer is, for example, 1 nm to 1 μm, preferably 2 nm to 500 nm, and more preferably 5 nm to 200 nm.

  When the organic EL element used in the light emitting part of the light emitting device of the present invention has an electron transport layer, known electron transport materials can be used, such as oxadiazole derivatives, anthraquinodimethane or derivatives thereof, benzoquinone Or a derivative thereof, naphthoquinone or a derivative thereof, anthraquinone or a derivative thereof, tetracyanoanthraquinodimethane or a derivative thereof, a fluorenone derivative, diphenyldicyanoethylene or a derivative thereof, a diphenoquinone derivative, or a metal complex of 8-hydroxyquinoline or a derivative thereof, polyquinoline Alternatively, derivatives thereof, polyquinoxaline or derivatives thereof, polyfluorene or derivatives thereof, and the like are exemplified.

  Specifically, JP-A-63-70257, JP-A-63-175860, JP-A-2-135359, JP-A-2-135361, JP-A-2-20988, JP-A-3-37992, The thing etc. which are described in the same 3-152184 gazette are illustrated.

  Of these, oxadiazole derivatives, benzoquinone or derivatives thereof, anthraquinones or derivatives thereof, or metal complexes of 8-hydroxyquinoline or derivatives thereof, polyquinoline or derivatives thereof, polyquinoxaline or derivatives thereof, polyfluorene or derivatives thereof are preferred, 2- (4-biphenylyl) -5- (4-t-butylphenyl) -1,3,4-oxadiazole, benzoquinone, anthraquinone, tris (8-quinolinol) aluminum, and polyquinoline are more preferable.

  There are no particular restrictions on the method of forming the electron transport layer, but in the case of a low molecular electron transport material, a vacuum deposition method from powder or a method by film formation from a solution or a molten state is used. Each method is exemplified by film formation from a molten state. When forming a film from a solution or a molten state, a polymer binder may be used in combination.

  The solvent used for film formation from a solution is not particularly limited as long as it can dissolve an electron transport material and / or a polymer binder. Examples of the solvent include chlorine solvents such as chloroform, methylene chloride, and dichloroethane; ether solvents such as tetrahydrofuran; aromatic hydrocarbon solvents such as toluene and xylene; ketone solvents such as acetone and methyl ethyl ketone; ethyl acetate, butyl acetate, An ester solvent such as ethyl cellosolve acetate is exemplified.

  Examples of film formation methods from a solution or a molten state include spin coating, nozzle coating, casting, micro gravure coating, gravure coating, bar coating, roll coating, wire bar coating, dip coating, and spray. Coating methods such as a coating method, a screen printing method, a flexographic printing method, an offset printing method, an ink jet printing method, a slit coating method, a capillary coating method, a dispenser method, and a microdispenser method can be used.

  As the polymer binder to be mixed, those not extremely disturbing charge transport are preferable, and those not strongly absorbing visible light are suitably used. As the polymer binder, poly (N-vinylcarbazole), polyaniline or a derivative thereof, polythiophene or a derivative thereof, poly (p-phenylenevinylene) or a derivative thereof, poly (2,5-thienylenevinylene) or a derivative thereof, polycarbonate , Polyacrylate, polymethyl acrylate, polymethyl methacrylate, polystyrene, polyvinyl chloride, or polysiloxane.

  The film thickness of the electron transport layer varies depending on the material used, and may be selected so that the drive voltage and the light emission efficiency are appropriate. However, at least a thickness that does not cause pinholes is required. If the thickness is too thick, the driving voltage of the element increases, which is not preferable. Therefore, the thickness of the electron transport layer is, for example, 1 nm to 1 μm, preferably 2 nm to 500 nm, and more preferably 5 nm to 200 nm.

  The substrate on which the organic EL element used in the light emitting part of the light emitting device of the present invention is formed is not particularly limited as long as it forms an electrode and forms an organic layer. For example, glass, plastic, polymer film, silicon Examples include a substrate (substrate). In the case of an opaque substrate, the opposite electrode is preferably transparent or translucent.

  In the present invention, the anode side is preferably transparent or translucent, but as the material of the anode, a conductive metal oxide film, a translucent metal thin film, or the like is used. Specifically, indium oxide, zinc oxide, tin oxide, and a composite film made of conductive glass made of indium / tin / oxide (ITO), indium / zinc / oxide, etc. (NESA) Etc.), gold, platinum, silver, copper and the like are used, and ITO, indium / zinc / oxide, and tin oxide are preferable. Examples of the production method include a vacuum deposition method, a sputtering method, an ion plating method, a plating method, and the like. Further, as the anode, an organic transparent conductive film such as polyaniline or a derivative thereof, polythiophene or a derivative thereof may be used.

The film thickness of the anode can be appropriately selected in consideration of light transmittance and electric conductivity, and is, for example, 10 nm to 10 μm, preferably 20 nm to 1 μm, more preferably 50 nm to 500 nm. is there.
Further, in order to facilitate charge injection on the anode, a layer made of a phthalocyanine derivative, a conductive polymer, carbon or the like, or an average film thickness of 2 nm or less made of a metal oxide, a metal fluoride, an organic insulating material, or the like. A layer may be provided.

  As a material of the cathode used in the organic EL element used in the light emitting portion of the light emitting device of the present invention, a material having a small work function is preferable. For example, metals such as lithium, sodium, potassium, rubidium, cesium, beryllium, magnesium, calcium, strontium, barium, aluminum, scandium, vanadium, zinc, yttrium, indium, cerium, samarium, europium, terbium, ytterbium, or the like Two or more of these alloys, or one or more of them and an alloy of one or more of gold, silver, platinum, copper, manganese, titanium, cobalt, nickel, tungsten, tin, or graphite or graphite intercalation compound Etc. are used. Examples of the alloy include magnesium-silver alloy, magnesium-indium alloy, magnesium-aluminum alloy, indium-silver alloy, lithium-aluminum alloy, lithium-magnesium alloy, lithium-indium alloy, calcium-aluminum alloy, and the like. The cathode may have a laminated structure of two or more layers.

  The thickness of the cathode can be appropriately selected in consideration of electric conductivity and durability, but is, for example, 10 nm to 10 μm, preferably 20 nm to 1 μm, and more preferably 50 nm to 500 nm.

  As a method for producing the cathode, a vacuum deposition method, a sputtering method, a laminating method in which a metal thin film is thermocompression bonded, or the like is used. In addition, a layer made of a conductive polymer or a layer having an average film thickness of 2 nm or less made of a metal oxide, a metal fluoride, an organic insulating material, or the like may be provided between the cathode and the organic material layer. A protective layer for protecting the polymer LED may be attached. In order to stably use the polymer LED for a long period of time, it is preferable to attach a protective layer and / or protective cover in order to protect the element from the outside.

  As the protective layer, a polymer compound, metal oxide, metal fluoride, metal boride and the like can be used. As the protective cover, a glass plate, a plastic plate having a low water permeability treatment on the surface, or the like can be used, and a method in which the cover is bonded to the element substrate with a heat effect resin or a photo-curing resin and sealed is preferable. Used for. If the space is maintained by using the spacer, it is easy to prevent the element from being damaged. If an inert gas such as nitrogen or argon is sealed in the space, the cathode can be prevented from being oxidized, and moisture adsorbed in the manufacturing process by installing a desiccant such as barium oxide in the space. It is easy to suppress damage to the element. Among these, it is preferable to take any one or more measures.

  As an embodiment of the light-emitting device of the present invention, a transparent substrate formed with a transparent electrode such as ITO is used, and an organic EL element serving as a light-emitting portion is formed on or above the substrate, thereby extracting light from the substrate side. be able to. In this case, the substrate may be transparent or translucent, and examples thereof include glass and plastic.

  In another embodiment, a light emitting layer containing an electrode and an organic substance is sequentially formed on or above the substrate, and the electrode formed on or above the substrate is made transparent, so that it is in a direction opposite to the substrate. The light can be taken out. Examples of the transparent electrode include a combination of a thin metal film thin enough to transmit light and a transparent electrode such as ITO. In this case, since the substrate is not necessarily transparent, a Si wafer or the like can also be used.

  The light emitting device of the present invention uses an organic EL element as a light source and needs to be appropriately sealed. As a sealing method, a method of attaching a metal can, a glass plate, or the like from the back side is simple, but film sealing with a multilayer laminate film of organic / inorganic substances (a thin film in which organic and inorganic substances are alternately stacked) is performed. It can also be used. In this case, in order to utilize the merit of film sealing, the thickness of the thin film is preferably less than 1 mm in total.

  What is necessary is just to arrange | position so that an anode and a cathode may overlap in the organic EL element used for the light emission part of the light-emitting device of this invention. In addition, in order to form a pixel that emits light in a specific portion, a method of installing a pixel by providing a window corresponding to the light emitting portion, an organic layer of a non-light emitting portion is formed extremely thick and substantially non-light emitting And a method of forming either one of the anode or the cathode or both electrodes in a desired pattern. By forming a pixel by any of these methods, arranging several electrodes so that the applied voltage (or current) can be controlled independently (for example, ON / OFF control), and connecting to the drive circuit, It can be set as the light emission part of the light-emitting device of this invention.

  The light emitting device of the present invention can be used for a copying machine, a facsimile, a printer, a scanner, and the like, for example, in combination with an electrophotographic photosensitive unit. Further, by combining with a CCD or the like, an image can be replaced with electronic information and recorded.

The light-emitting device of the present invention operates as an image forming apparatus by further disposing an element that functions by receiving light emitted from the pixel relative to the surface of the pixel. Examples of the element that functions by receiving light include an electrophotographic photosensitive portion (charge movement, charge loss, and the like occur by receiving light), a CCD, and the like.
For example, FIG. 5 shows an example in which an electrophotographic photosensitive portion is used as a light receiving portion and combined with a light emitting portion. FIG. 6 shows an example of an image forming apparatus used in a copying machine, a facsimile, or the like, in which a light emitting unit and a photosensitive unit are combined. FIG. 9 shows an example of an apparatus that can record and replace electronic images with electronic information by combining a CCD or the like as a light receiving unit with a light emitting unit, and is used in a scanner.

  Furthermore, the light emitting unit of the light emitting device of the present invention may be composed of pixels arranged one-dimensionally or may be composed of pixels arranged two-dimensionally on a plane. In addition, if the opposing light receiving unit has a mechanism that moves while keeping a constant interval, two-dimensional image information can be sequentially drawn.

  Examples of embodiments will be shown below to describe the present invention in more detail, but the present invention is not limited to these.

Example 1
Etching is performed on a glass substrate on which an ITO film having a thickness of 150 nm is formed by sputtering so that a portion (pixel) where ITO and a cathode to be formed later overlap with each other has a desired size and layout.
Using a solution obtained by filtering a suspension of poly (3,4-ethylenedioxythiophene) / polystyrene sulfonic acid (manufactured by Bayer, BaytronP AI4083) through a 0.2 μm membrane filter on the glass substrate with ITO, spin. A thin film having a thickness of about 70 nm is formed by coating, and dried on a hot plate at 200 ° C. for 10 minutes. Next, a light emitting layer having a thickness of about 80 nm is formed by spin coating using a xylene solution (1-2% by weight) of a polymer light emitting material. Further, after drying this at 80 ° C. for 1 hour under reduced pressure, about 5 nm of calcium and then about 80 nm of aluminum are vapor-deposited to form a cathode. The cathode is formed in a pattern using a mask or the like so that a portion overlapping with ITO has a desired size and layout.
By the above method, an organic EL element array having a pixel pitch of 50 μm and a pixel size of 25 μm × 50 μm is manufactured. At this time, the pixel spacing is 25 μm and L ₁ × 2 = L ₂ (T1 = 25 μm, T2 = 50 μm, L ₁ = 25 μm, L ₂ = 50 μm, n = 2).
At the time of driving, heat is generated in the light emitting pixels, but when the pixel size and the interval between the pixels are formed under the above conditions, heat radiation to the surroundings is more likely to occur, so that damage caused by heat can be reduced. Long driving time is possible.

Example 2 (Example using phosphorescent material)
An organic EL device is produced in the same manner as in Example 1 except that instead of the polymer light emitting material in Example 1, a mixture of the polymer light emitting material and the triplet light emitting complex is used. This element generates heat in the pixel that emits light during driving. However, when the pixel size and the pixel interval are formed under the same conditions as in Example 1, heat dissipation to the surroundings is likely to occur, so that damage due to heat can be reduced. Can be driven for a longer time.

Example 3 (Example using a low-molecular fluorescent material)
In Example 1, instead of applying the polymer light-emitting material (spin coating), the sample was put in a vacuum deposition apparatus, and a coating layer of a suspension of poly (3,4-ethylenedioxythiophene) / polystyrene sulfonic acid was used. A light emitting layer is formed by vapor-depositing a low molecular fluorescent material on the top, and then an electron transporting layer is formed by vapor depositing a low molecular electron transporting material. Subsequently, 5 nm of calcium and about 80 nm of aluminum are deposited to form a cathode. An organic EL element is produced using the same cathode pattern as in Example 1.
This element generates heat in the pixel that emits light during driving. However, when the pixel size and the pixel interval are formed under the same conditions as in Example 1, heat dissipation to the surroundings is likely to occur, so that damage due to heat can be reduced. Can be driven for a longer time.

Comparative Example In Example 1, an organic EL element array having a pixel pitch of 50 μm and a pixel size of 40 μm × 50 μm is manufactured. At this time, the pixel spacing is 10 μm and L ₁ × 5 = L ₂ (T1 = 40 μm, T2 = 50 μm, L ₁ = 10 μm, L ₂ = 50 μm, n = 5) . An organic EL device is produced in the same manner as in Example 1. Since this element has insufficient heat dissipation during driving, it is thermally damaged and has a high deterioration rate.

  Comparing Examples 1 to 3 with the comparative example, it can be seen that the durability is improved by appropriately selecting the pixel layout. These characteristics are very excellent properties as a light emitting device for image formation.

It is a figure which shows the structure (cross section) of a light-emitting device. It is a figure which shows the structural example of a light-emitting device. It is a diagram illustrating a distance (L ₁₎ between pixels adjacent to the pixel width (L _2). It is a figure which shows the linear direction length (T1) and right-angle direction length (T2) of a light emitting element array. It is a figure which shows the example of arrangement | positioning of a light emission part and a light-receiving part. 1 is a diagram illustrating an example of an image forming apparatus. It is a figure which shows the example of arrangement | positioning of a light emission part, a light-receiving part, and a condensing element. It is a figure which shows the condensing by a condensing element. It is a figure which shows the example of an image memory | storage device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Base | substrate 2 Anode 3 Layer containing organic substance 4 Cathode 5 Sealing layer 6 Pixel 7 Drive circuit 8 Control circuit 9 Light emitting pixel 10 Non-light emitting pixel 11 Light receiving and charge transfer portion 12 Light receiving and surface charged Part 13 Photosensitive drum 14 Charger 15 Light source (organic EL)
16 Developing device 17 Transfer device 18 Fixing device 19 Static eliminator 20 Cleaner 21 Paper 22 Light source (organic EL)
23 Light receiving element (CCD, etc.)
24 control circuit 25 storage device 26 condensing element

Claims (11)

In a light-emitting device having an anode and a cathode, and a light-emitting layer including at least one organic substance sandwiched between them, and having two or more pixels each of which emits light by passing a current between the electrodes, all pixels Are formed on or above the same substrate, and at least one of the electrodes of each pixel is independently connected to the drive circuit for each pixel, and the applied voltage or current can be controlled independently. , the minimum distance between adjacent pixels in each pixel L _1, the maximum width of the pixel when the _{L 2, L 1 × n ≧} L 2 [wherein, n represents a number from 0.1 to 3 . And L ₂ is 100 μm or less.   The light emitting device according to claim 1, wherein n represents a number of 0.1 or more and 2 or less. The light emitting device according to claim 1, wherein the L ₂ is less than 100 μm.   The light emitting device is formed of a light emitting element array in which the light emitting devices are linearly arranged, and the size of each pixel is larger in length in the direction perpendicular to the straight line than in length in the linear direction. The light emitting device according to 1.   5. The light emission according to claim 1, further comprising a light receiving element that functions by receiving light emitted from the pixel relative to the surface of the pixel, and operates as an image forming apparatus. apparatus.   6. The light emitting device according to claim 5, wherein the light emitting device operates as an image forming apparatus having a light condensing element having a function of condensing light emitted from the pixel on the light receiving element between the pixel and the light receiving element opposed thereto. .   The light-emitting device according to claim 6, wherein the light-collecting function of the light-collecting element has a function of collecting light mainly in a plane perpendicular to the linear direction of the light-emitting element array.   The light emitting device according to any one of claims 1 to 7, wherein at least one of the organic substances contained in the light emitting layer is a phosphorescent compound. The light emitting device according to any one of claims 1 to 8, wherein at least one of organic substances contained in the light emitting layer is a polymer compound including one or more types of repeating units represented by the formula (1).
-Ar _1- (1)
[Ar ₁ represents a group selected from the group consisting of an arylene group, a divalent heterocyclic compound group, and a divalent aromatic amine group. ]   The light emitting device according to any one of claims 1 to 9, wherein at least one of organic substances contained in the light emitting layer is a compound having fluorescence. The method for manufacturing a light emitting device according to any one of claims 1 to 10, wherein the light emitting layer containing the organic substance is formed by applying a solution containing a light emitting material on or above a substrate. Production method.