JP2002373793A - Exposure device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exposure device on which an organic EL element array capable of easily forming a luminous dot in an optical size is mounted. SOLUTION: The organic EL element array is composed of a conductive material 8 formed on a translucent anode 7 and having an opening part from which the translucent anode 7 is exposed; a hole transport layer 9 for injecting holes in the translucent anode 7; a luminescent layer formed so as to cover the opening part and lighting the position of the opening part; a cathode formed on the luminescent layer and in which electrons are injected. The exposure device has an organic EL element array substrate 3 equipped with the organic EL element array, and a driver IC for driving the organic EL element array, and the luminous dot 15 is constituted with the opening part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure apparatus and an image forming apparatus used in an electrophotographic apparatus such as a copying machine and a printer, and more particularly to a technique effective when applied to an optical printer head.

[0002]

2. Description of the Related Art Exposure methods for writing a latent image on a photoreceptor are known from the viewpoints of speed, miniaturization, and high reliability.
The ED array method is dominant.

Here, the printing process using the LED printer head generally proceeds in the following order.

First, a photoreceptor is uniformly charged using a charger, and a light beam from an LED array is imaged on a charged surface via a lens or the like (exposure) to form a latent image. Next, this latent image is made visible by a developing device, and then transferred and fixed on a recording sheet. At the same time, the residual toner is cleaned and the residual potential is removed, and the printing process is completed.

[0005] There are an inorganic LED array and an organic EL element array in the LED element array. In the case of the inorganic LED array system, an LED array substrate is expensive and an array cannot be formed with one substrate. Therefore, it is necessary to linearly align the cut chips. At this time, since the light emission characteristics between the chips do not match, a variation in the light emission amount in one line of the array always occurs.

[0006] In order to correct the variation in the amount of emitted light in one line of the array, for example, the distribution of the emitted light amount of all elements in the entire array in the initial stage is measured, and the light amount correction data corresponding to each light emitting element is created. And a light amount correction circuit of the drive circuit based on the correction (for example, current / pulse width correction, etc.)
There is a technique in which light amount correction is performed by using However, according to this, there are problems such as a complicated driving circuit and an increase in cost.

[0007] In order to cut out or align the chips in a straight line, a high-precision cutting technology and a mounting technology are required. It has become difficult and has been a factor in increasing costs.

On the other hand, the organic EL element array can be formed on an inexpensive glass substrate or the like, and the array can be obtained from a single substrate. Therefore,
There is no variation in the amount of emitted light between chips as in an inorganic LED array, and a circuit for correcting the amount of emitted light is not required. Therefore, since the array can be manufactured at low cost, development is proceeding from such an advantage.

FIG. 12 is a perspective view showing a basic configuration example of an organic EL element as a display element. FIG. 12 shows an example in which a dot matrix display element is used.

[0010] In FIG. 12, an IT
A light-transmitting anode 62 such as O (Indium Tin Oxide) is provided in a stripe shape, and a hole transport layer 6 is formed thereon.
3. After forming the light emitting layer 64, the cathode 65 is formed using a vacuum deposition mask having a stripe-shaped opening.
At this time, the stripe direction of the cathode 65 is aligned with the direction crossing the translucent anode 62. And the translucent anode 6
By injecting a current into the light emitting layer 64 sandwiched between the cathode 2 and the cathode 65, light emission in a dot matrix is obtained and functions as a display element.

However, in order to use this organic EL element array as a printer head, it is necessary to determine the size of an area to be a light emitting dot. For example, 200dp
When only the resolution of i is considered, the pitch of the light emitting dots is about 130 μm. And about 600 dpi is about 40
The pitch of the light emitting dots is reduced in proportion to the increase in resolution, for example, about 20 μm for μm and 1200 dpi.

Referring to FIG. 12, the size of a light emitting dot is determined by the area where the anode 62 and the cathode 65 intersect in a plan view. The area on the plane on the side of the anode 62 can be determined with high accuracy using the photolitho technology which is a semiconductor technology, so that it can sufficiently cope with a light emitting dot pitch of 1200 dpi. In addition, since the light emission characteristics deteriorate when exposed to a developing solution, the cathode material formed after the organic layer is deposited cannot be processed by photolithography. Then,
The area of the flat surface on the side of the cathode 65 is determined by the size of the opening provided in the dedicated pattern mask at the time of vacuum vapor deposition. 200 dpi
Some things are quite difficult to deal with.

In an organic EL element array, a technology for miniaturizing the light emitting dot pitch with a simple structure is disclosed in Japanese Patent Application Laid-Open No. 200-200.
0-133461. According to this, a conductive light-shielding layer having an opening is formed on the surface of the light-transmitting first electrode formed on the light-transmitting substrate to form a light-emitting dot area. Is used as an electrical connection layer with an external drive circuit, so that even fine light-emitting dots can be created with a simple structure, and an organic EL light-emitting source that can be easily connected to an external drive circuit can be obtained.

FIG. 10 is a perspective view showing a conventional organic EL element array substrate and external circuit terminals, and FIG. 11A is a cross-sectional view showing an enlarged main part of FIG.

In these drawings, an ITO electrode layer 52 serving as a first electrode is formed on a light-transmitting substrate 51, and a gold electrode layer serving as a light shielding layer having an opening serving as a light emitting hole 56 provided thereon. 53 is formed. Then, an organic compound layer 54 and a cathode layer 55 are sequentially formed to form an organic EL element array 50.

[0016]

However, Japanese Patent Laid-Open Publication
In the case of −133461, the external circuit terminal 5
For example, an Au (gold) electrode suitable for wire bonding with the wire 7 and the wire 58 is used. However, Au has a higher work function than the organic compound layer 54 and the cathode layer 55, and thus is used as an anode of the organic EL element array 50. Works.

At this time, as shown in FIG. 11B as an enlarged sectional view of a portion S in FIG.
A considerable amount of light emitted from the device passes through the light exit hole 56 and passes through the IT.
Light is emitted to the outside of the substrate via the O transparent electrode layer 52 and the translucent substrate 51, but most of the light from the light emitting point A is blocked and reflected by the gold electrode layer 53 which is a light shielding layer. Further, since the light is repeatedly attenuated by the gold electrode layer 53 and the cathode layer 55 many times, the light is attenuated, so that the amount of light emitted from the light emitting point A through the light emitting hole 56 is smaller than that of the light emitting point B.

When the resolution is increased to 600 dpi or 1200 dpi, the area of the overlapping portion of the gold electrode layer 53 on the ITO transparent electrode layer 52 is not so negligible as compared with the area of the light emitting hole 56 which becomes the light emitting dot area. Size. Therefore, as compared with the case where the gold electrode layer 53 is not provided, the efficiency of extracting light to the outside with respect to the applied current is reduced, so that the power consumption increases in order to obtain a predetermined luminance as the light emitting dot. There is a problem.

Accordingly, an object of the present invention is to provide an exposure apparatus and an image forming apparatus equipped with an organic EL element array capable of easily forming a light emitting dot into an arbitrary size.

[0020]

In order to solve this problem, an exposure apparatus according to the present invention comprises: a conductive material formed on a light-transmitting anode and having an opening for exposing the light-transmitting anode;
An organic layer comprising a hole transport layer for injecting holes into the translucent anode, a light emitting layer formed to cover the opening and emitting light at the position of the opening, and a cathode formed on the light emitting layer and injecting electrons. It has an organic EL element array substrate provided with an EL element array, and a driver IC for driving the organic EL element array, and a light emitting dot is constituted by an opening.

Further, the exposure apparatus of the present invention comprises a hole transport layer for injecting holes into the light-transmissive anode, a light-emitting layer emitting light by the light-transmissive anode into which holes are injected, and a light-emitting layer formed on the light-emitting layer. An organic EL element array substrate having an organic EL element array composed of a cathode for injecting electrons through the substrate, and a driver IC for driving the organic EL element array. Is provided with a light reflection layer that reflects light traveling toward the organic EL element array substrate.

Further, the image forming apparatus of the present invention uses such an exposure apparatus.

As a result, it is possible to easily form the luminescent dots into an arbitrary size, and it is possible to obtain an organic EL element array having good luminous efficiency and low power consumption.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION The invention according to claim 1 of the present invention relates to a light-transmitting anode formed on a light-transmitting anode, the conductive material having an opening for exposing the light-transmitting anode. An organic EL element array including a hole transport layer for injecting holes, a light emitting layer formed to cover the opening and emitting light at the position of the opening, and a cathode formed on the light emitting layer and injecting electrons. An exposure device having an organic EL element array substrate and a driver IC for driving the organic EL element array, wherein light-emitting dots are formed by openings, and light is emitted in the shape of the openings formed in the conductive material. Since the dots are defined and light is efficiently emitted from the dots, the light emitting dots can be easily formed into an arbitrary size, and an organic EL element array with good light emitting efficiency and low power consumption is mounted. Exposure equipment It has the effect that is.

According to a second aspect of the present invention, there is provided a hole transport layer for injecting holes into the light-transmitting anode, a light-emitting layer emitting light by the light-transmissive anode into which holes are injected, and a light-emitting layer on the light-emitting layer. An organic EL element array substrate including an organic EL element array formed of a cathode for injecting electrons and having an organic EL element array, and a driver IC for driving the organic EL element array; In between, there is an exposure apparatus provided with a light reflection layer that reflects light directed toward the organic EL element array substrate, and emits light in the direction of the cathode.
Since the light emitting dots are defined by the area of the cathode, the light emitting dots can be easily formed in an arbitrary size, and the light does not pass through the organic EL element array substrate. There is an effect that an exposure apparatus equipped with an organic EL element array having better luminous efficiency and low power consumption is obtained without deterioration of light amount due to reflection of light at an interface with the element array substrate.

According to a third aspect of the present invention, there is provided an image forming apparatus in which the exposure apparatus according to any one of the first to third aspects is used. And an image forming apparatus using an exposure apparatus equipped with an organic EL element array having good luminous efficiency and low power consumption can be obtained.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. In these drawings, the same members are denoted by the same reference numerals, and duplicate description is omitted.

(Embodiment 1) FIG. 1 is a perspective view showing an exposure apparatus according to Embodiment 1 of the present invention, FIG. 2 is a plan view showing an organic EL array substrate in the exposure apparatus of FIG. 1, and FIG. FIG. 4 is a sectional view taken along line AA ′ of FIG.
FIG. 5 is a schematic view showing an image forming apparatus using the exposure apparatus shown in FIG.

First, the organic EL element array will be described in detail. The description of the organic EL element array is as follows.
The same applies to the second embodiment.

An organic EL element array is one organic EL element.
This is an elementary array element in which the light emitting portions of the element are arranged in an array (linear).

The organic EL element array substrate is a substrate on which an organic EL element array is formed. Here, as a substrate material, inorganic oxide glass such as transparent or translucent soda lime glass, barium / strontium-containing glass, lead glass, aluminosilicate glass, borosilicate glass, barium borosilicate glass, quartz glass, etc. Inorganic glass such as fluoride glass, or transparent or translucent polyethylene terephthalate, polycarbonate, polymethyl methacrylate, polyether sulfone, polyvinyl fluoride, polypropylene, polyethylene, polyacrylate, amorphous polyolefin,
Polymer film such as fluororesin or opaque S
i (silicon), Ge (germanium), GaAs (gallium arsenide), InAs (indium arsenide), GaSb
(Gallium antimony), InSb (indium antimony) or other inorganic semiconductor substrate, or opaque Fe
(Iron), Al (aluminum), Cu (copper), Ag
A metal or alloy such as (silver), a metal compound substrate, or a polymer substrate such as an opaque plastic, a thermosetting resin, or a photocurable resin is used. Note that a circuit including a resistor, a coil, an inductor and the like for driving the organic electroluminescence element may be formed on the surface of the substrate or inside the substrate.

As the anode, a transparent electrode is generally used. The transparent electrode is a light-transmitting conductive film, and is a metal oxide such as indium tin oxide (ITO), tin oxide (SnO ₂ ), zinc oxide (ZnO), or SnO: S
b (antimony), a transparent conductive film made of a mixture such as ZnO: Al (aluminum), or Al (aluminum) or Cu having a thickness that does not impair the transparency.
A metal thin film such as (copper), Ti (titanium), or Ag (silver), a metal thin film such as a mixed thin film or a laminated thin film of these metals, or a conductive polymer such as polypyrrole can be used. Further, a transparent electrode can be formed by laminating a plurality of the above-mentioned transparent electrode materials, and is formed by resistance heating evaporation, electron beam evaporation, sputtering, electric field polymerization, chemical polymerization, or the like. It is preferable that the transparent electrode has a thickness of 1 nm or more in order to have sufficient conductivity or prevent uneven light emission due to unevenness of the substrate surface. Also, in order to have sufficient transparency, 500
More desirably, the thickness is not more than nm. In the present invention, the definition of “transparent”, “translucent” or “translucent” refers to a degree that does not hinder the visual recognition of light emission by the organic EL element or the organic EL element array.

In addition to Cr (chromium),
A metal having a large work function, such as Ni (nickel), Cu (copper), Sn (tin), W (tungsten), Au (gold), or an alloy thereof, an oxide, or the like can be used. A stacked structure of a plurality of materials may be used. However, when the anode is not used as a transparent electrode, it is preferable that the anode be formed of a material that reflects light in order to maximize the effect of the light angle conversion means.

Also, an amorphous carbon film may be provided on the anode. In this case, both have a function as a hole injection electrode. That is, holes are injected from the anode into the light emitting layer or the hole transport layer via the amorphous carbon film. The amorphous carbon film is formed between the anode and the light emitting layer or the hole transport layer by a sputtering method. As the carbon target by sputtering, there are isotropic graphite, anisotropic graphite, glassy carbon, and the like. Although not particularly limited, isotropic graphite having high purity is suitable.

The fact that the amorphous carbon film is excellent will be specifically described. When the work function of the amorphous carbon film is measured using a surface analyzer AC-1 manufactured by Riken Keiki, the work function of the amorphous carbon film is Wc = 5.40 eV. Here, the work function of ITO generally used as an anode is Wf (I
Since TO) = 5.05 eV, holes can be more efficiently injected into the light emitting layer or the hole transport layer by using the amorphous carbon film. When an amorphous carbon film is formed by a sputtering method, reactive sputtering is performed in a mixed gas atmosphere of nitrogen or hydrogen and argon in order to control an electric resistance value of the amorphous carbon film. Furthermore, in a thin film forming technique by a sputtering method or the like, if the film thickness is set to 5 nm or less, the film becomes an island structure, and a uniform film cannot be obtained. Therefore, when the thickness of the amorphous carbon film is 5 nm or less, the electric resistance becomes too high, and no current flows, and efficient light emission cannot be obtained. Further, when the thickness of the amorphous carbon film is 100 nm or more, the color of the film becomes blackish, and the light emission of the organic electroluminescence element is not sufficiently transmitted.

The light emitting layer material preferably has a fluorescent property in the visible region and is preferably made of a phosphor having good film-forming properties, such as Alq ₃ or Be-benzoquinolinol (BeBq ₂ ).
And 2,5-bis (5,7-di-t-pentyl-2)
-Benzoxazolyl) -1,3,4-thiadiazole, 4,4'-bis (5,7-bentyl-2-benzoxazolyl) stilbene, 4,4'-bis [5,7-di- (2-Methyl-2-butyl) -2-benzoxazolyl] stilbene, 2,5-bis (5,7-di-t-ventyl-2-benzooxazolyl) thiofin, 2,5-
Bis ([5-α, α-dimethylbenzyl] -2-benzoxazolyl) thiophene, 2,5-bis [5,7-di- (2-methyl-2-butyl) -2-benzoxazolyl -3,4-diphenylthiophene, 2,5-bis (5-methyl-2-benzoxazolyl) thiophene,
4,4'-bis (2-benzoxazolyl) biphenyl, 5-methyl-2- [2- [4- (5-methyl-2-
Benzoxazoles such as benzoxazolyl) phenyl] vinyl] benzoxazolyl and 2- [2- (4-chlorophenyl) vinyl] naphtho [1,2-d] oxazole, and 2,2 ′-(p-phenyl Range vinylene)
Benzothiazoles such as bisbenzothiazole, 2-
Fluorescent whitening agents such as [2- [4- (2-benzimidazolyl) phenyl] vinyl] benzimidazole, 2- [2- (4-carboxyphenyl) vinyl] benzimidazole, etc .; Quinolinol) magnesium, bis (benzo-8-quinolinol)
Zinc, bis (2-methyl-8-quinolinolate) aluminum oxide, tris (8-quinolinol) indium, tris (5-methyl-8-quinolinol) aluminum, lithium 8-quinolinol, tris (5-chloro-8-quinolinol) Gallium, bis (5-chloro-8
-Quinolinol) calcium, poly [zinc-bis (8-
8-hydroxyquinoline-based metal complexes such as hydroxy-5-quinolinonyl) methane and metal-chelated oxinoid compounds such as dilithium epindridione;
Bis (2-methylstyryl) benzene, 1,4- (3-
Methylstyryl) benzene, 1,4-bis (4-methylstyryl) benzene, distyrylbenzene, 1,4-bis (2-ethylstyryl) benzene, 1,4-bis (3
-Ethylstyryl) benzene, styrylbenzene compounds such as 1,4-bis (2-methylstyryl) 2-methylbenzene, and 2,5-bis (4-methylstyryl) pyrazine, 2,5-bis (4- Ethylstyryl) pyrazine,
2,5-bis [2- (1-naphthyl) vinyl] pyrazine, 2,5-bis (4-methoxystyryl) pyrazine,
Distilpyrazine derivatives such as 2,5-bis [2- (4-biphenyl) vinyl] pyrazine, 2,5-bis [2- (1-pyrenyl) vinyl] pyrazine, naphthalimide derivatives, perylene derivatives, Oxadiazole derivatives, aldazine derivatives, cyclopentadiene derivatives, styrylamine derivatives, coumarin derivatives, aromatic dimethylidin derivatives, and the like are used. Further, anthracene, salicylate, pyrene, coronene and the like are also used.

In addition to the single-layer structure of only the light-emitting layer, a two-layer structure of a hole transport layer and a light-emitting layer or a light-emitting layer and an electron transport layer, or a three-layer structure of a hole transport layer, a light-emitting layer, and an electron transport layer Any structure may be used. However, in the case of such a two-layer structure or a three-layer structure, the hole transport layer and the anode or the electron transport layer and the cathode are stacked so as to be in contact with each other.

As the hole transport layer, a layer having high hole mobility, being transparent and having good film-forming properties is preferable. In addition to TPD, porphyrin compounds such as porphine, tetraphenylporphine copper, phthalocyanine, copper phthalocyanine, titanium phthalocyanine oxide, and 1,1-bis {4- (di-P-tolylamino) phenyl} cyclohexane, 4, 4 ′, 4 ″ -trimethyltriphenylamine, N, N, N ′, N′-tetrakis (P-tolyl)
-P-phenylenediamine, 1- (N, N-di-P-tolylamino) naphthalene, 4,4'-bis (dimethylamino) -2-2-2'-dimethyltriphenylmethane, N,
N, N ', N'-tetraphenyl-4,4'-diaminobiphenyl, N, N'-diphenyl-N, N'-di-m
-Tolyl-4, N, N-diphenyl-N, N'-bis (3-methylphenyl) -1, 1'-4, 4'-diamine, 4'-diaminobiphenyl, N-phenylcarbazole, etc. Aromatic tertiary amines, 4-di-P-tolylaminostilbene, 4- (di-P-tolylamino) -4 ′
Stilbene compounds such as-[4- (di-P-tolylamino) styryl] stilbene, triazole derivatives, oxazizole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, , Annealed amine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styryl anthracene derivatives, fluorenone derivatives, hydrazone derivatives, silazane derivatives, polysilane aniline copolymers, high molecular oligomers, styrylamine compounds Organic materials such as aromatic dimethylidin compounds and poly-3-methylthiophene are used. Further, a polymer-dispersed hole transport layer in which a low molecular weight organic material for a hole transport layer is dispersed in a polymer such as polycarbonate is also used.

As the electron transporting layer, oxadiazole derivatives such as 1,3-bis (4-tert-butylphenyl-1,3,4-oxadiazolyl) phenylene (OXD-7) and anthraquinodimethane derivatives And diphenylquinone derivatives.

The cathode is an electrode into which electrons are injected, and it is necessary to efficiently inject electrons into the light emitting layer or the electron transporting layer.
Metals such as In (indium), Mg (magnesium), Ti (titanium), Ag (silver), Ca (calcium), and Sr (strontium), or oxides and fluorides of these metals and their alloys and laminates Are generally used. In addition, a transparent cathode may be formed by forming an ultrathin film having high light transmittance using a metal having a small work function at an interface in contact with the light emitting layer or the electron transport layer, and laminating a transparent electrode thereon. It is possible. Particularly, Mg, Mg-Ag alloy having a small work function, Al-Li alloy or Sr-Mg alloy described in JP-A-5-121172 or A
l-Sr alloy, Al-Ba alloy, etc. or LiO ₂ / A
A laminated structure such as 1 or LiF / Al is suitable as a cathode material. As a film forming method, resistance heating evaporation, electron beam evaporation, and sputtering are used. However, when the cathode is not used as a transparent electrode, it is preferable that the cathode is formed of a material that reflects light in order to maximize the effect of the light angle conversion means.

As shown in FIG. 1, in the exposure apparatus of the present embodiment, an organic EL element array substrate 3 is provided with an organic EL element.
An element array 2 is provided. Further, the organic EL element array substrate 3 is provided on the drive circuit substrate 1 on which a plurality of driver ICs 4 are mounted. The organic EL element array 2 and the driver IC 4 on the drive circuit board 1
They are electrically connected to each other by wire bonding.

A focusing rod lens array 5 is provided below the drive circuit board 1, and an organic EL element array 2 is provided.
The light from the light emitting dot 15 (FIG. 2) passes through the organic EL element array substrate 3 and the drive circuit substrate 1 and forms an image on the photoreceptor 6 via the converging rod lens array 5.

Light emitting dots 15 on organic EL element array 2
Since ON / OFF switching is required every time, the number of driver ICs 4 is required by dividing the total number of dots per head by the total number of dots per driver IC 4.

The organic EL element array 2 can be formed into a thin film by a dry method or a wet method, and a photolithography technique used in a semiconductor manufacturing process can be partially used.
The light emitting dots 15 can be collectively formed, and high-density patterning can be performed with high accuracy. In other words, the labor of arranging a plurality of chips of the inorganic LED elements can be omitted, the array lines can be formed collectively, and the life can be longer than that of the inorganic LED elements, so that the cost can be significantly reduced.

As shown in FIG. 2, the organic EL element array 2
The light emitting dots 15 are created on the line corresponding to the resolution. These luminescent dots 15 are patterned by the translucent anode 7 and the separation layer 12. Each of the light emitting dots 15 is electrically connected to the driver IC 4 by wire bonding through the translucent anode 7 and the connection electrode 14. There is a common cathode 11 (FIGS. 3 and 4) on the cathode side, which is electrically connected to the drive circuit board 1 by wire bonding.

Such an organic EL element array 2 is formed as follows.

That is, in FIGS. 3 and 4, first, a light-transmissive anode 7 into which holes are injected is formed in a pattern on the organic array element substrate 3, and a conductive material 8 is formed thereon. At this time, as shown in FIG. 3, an opening a for forming the light emitting dot 15 is provided in the conductive material 8, and the light-transmitting anode 7 is exposed from the opening a.

Next, a separation layer 12 that intersects with the translucent anode 7 is formed by patterning so as to avoid the opening a. Thereafter, the hole transport layer 9 and the light emitting layer 10 are sequentially patterned so as to cover the opening a with a dedicated pattern mask, and the cathode 11 is formed using another dedicated pattern mask. Then, after the connection electrode 14 is formed in a pattern to electrically connect the translucent anode 7, the conductive material 8 and the connection electrode 14, the light-emitting portion is exposed to the surrounding environment (particularly moisture) by using the sealing material 13. Airtight sealing to prevent deterioration.

Thus, the light emitting dots 15 are defined by the conductive material 8 provided with the openings a. In addition, since the light emitting layer 10 located in the opening a emits light but the light emitting layer 10 in other places does not emit light, light emitted from the opening a as the light emitting dot 15 can be obtained efficiently.

Accordingly, it is possible to easily form the light emitting dots 15 in an arbitrary size, and it is possible to obtain an exposure apparatus in which the organic EL element array 2 having good luminous efficiency and low power consumption is mounted.

Next, a printing process by an image forming apparatus using such an exposure apparatus will be described with reference to FIG.

First, the surface of the photoreceptor 6 is uniformly charged using the charger 19.

Next, an exposure light beam 21 from an exposure device 20 equipped with the above-mentioned organic EL element array is formed on the surface of the charged photoreceptor 6 through a selfoc lens, a converging rod lens and the like. (Exposure), a latent image is formed.
That is, exposure corresponding to a time-series digital signal of target image information is performed on the charged surface, and an electrostatic latent image corresponding to the image information is formed.

Then, the electrostatic latent image is developed as a toner image by the developing device 22 using the insulating toner. On the other hand, the recording paper 24 is introduced at a predetermined timing to the transfer portion of the transfer device 23 which is brought into contact with the photoreceptor 6 with a predetermined pressing force, and transfer is performed by applying a predetermined transfer bias voltage. As a result, the recording paper 24 to which the toner image has been transferred is separated from the surface of the photoreceptor 6 and introduced into a fixing device 25 such as a heat fixing system, where the toner image is fixed and printed.

At the same time, the residual toner is cleaned by the cleaner 26 and the residual potential is removed by the charge remover 27, thereby completing one printing process.

As described above, an image forming apparatus capable of coping with high resolution and low power consumption with a simple structure is constructed using the exposure apparatus 20 equipped with the organic EL element array.

(Embodiment 2) FIG. 6 is a perspective view showing an exposure apparatus according to Embodiment 2 of the present invention, FIG. 7 is a plan view showing an organic EL array substrate in the exposure apparatus of FIG. 6, and FIG. FIG. 9 is a sectional view taken along line CC ′ of FIG.
It is sectional drawing along the D 'line.

As shown in FIG. 6, in the exposure apparatus of the present embodiment, an organic EL element array 2a is provided on an organic EL element array substrate 3. Further, the organic EL element array substrate 3 is provided on the drive circuit substrate 1 on which a plurality of driver ICs 4 are mounted. The organic EL element array 2 and the driver IC 4 on the drive circuit board 1 are electrically connected to each other by wire bonding.

A focusing rod lens array 6 is provided above the organic EL element array substrate 3, and light from the light emitting dots 16 (FIG. 7) of the organic EL element array 2a passes through the focusing rod lens array 5. The light forms an image on the photoreceptor 6 via the

As shown in FIG. 7, a light reflecting layer 17 is provided between the organic EL element array substrate 3 and the translucent anode 7. As a result, the light is extracted from the organic EL element array 2a in a direction opposite to that of the organic EL element array substrate 3, so that the light passes through the converging rod lens array 5 disposed on the organic EL element array substrate 3. The photoreceptor 6 can be exposed.

In this extraction direction, light does not pass through the organic EL element array substrate 3, so that the organic EL element
There is no deterioration in light quantity due to reflection of light at the interface between the element array 2a and the organic EL element array substrate 3, and more light quantity can be extracted. As a result, the drive current can be reduced, and an exposure apparatus using the organic EL element array 2a with low power consumption can be obtained.

[0062] Such an organic EL element array 2a is formed as follows.

8 and 9, a light reflection layer 17 is first formed on the organic EL element array substrate 3, and a light-transmissive anode 7 is formed thereon. Intersecting separation layers 12 are patterned.

Next, the hole transport layer 9 and the light emitting layer 10 are sequentially laminated by using a dedicated pattern mask to form a pattern at a desired position.
To form

At this time, the light-transmissive cathode 11a in the light-emitting direction is a laminated film in which a light-transmissive electrode is laminated on a cathode made of a metal material having a low work function and having a light-transmitting property by forming a thin film. Consists of

As shown in FIG. 9, a connection electrode 14 is patterned on the light reflection layer 17 drawn as a wiring to electrically connect the light reflection layer 17, the translucent anode 7 and the connection electrode 14 to each other. After the connection, the light emitting section is sealed using a sealing material 13 so as not to be deteriorated by the surrounding environment (particularly, moisture).

As a result, a light emitting area is defined as the light emitting dots 16 by the translucent anode 7, the separation layer 12, and the translucent cathode 11a, so that an exposure apparatus using the low power consumption organic EL element array 2a is obtained. Can be

[0068]

Next, specific examples of the present invention will be described.

The present embodiment shows an exposure apparatus and an image forming apparatus provided with an organic EL light emitting element array as a light emitting source.

(Example 1) A glass substrate was used as the organic EL element array substrate 3. An ITO film having a thickness of 160 nm to be the light-transmitting anode 7 was formed on the entire surface of the substrate by sputtering, and then a conductive film was formed on the entire surface. Al (aluminum) as the material 8 was deposited to a thickness of 150 nm. And this A
l Resist material (Tokyo Oka Co., OFPR-80)
0) was applied by spin coating to form a resist film having a thickness of 10 μm, and the resist film was patterned into a predetermined shape by masking, exposing, and developing. At this time, a pattern to be the opening a of the light emitting dot 15 was formed.

Next, the substrate was immersed in a mixed solution of nitric acid and phosphoric acid at room temperature, and only the Al film was etched to form a pattern. The resist film is removed, and a resist material (OFPR-800, manufactured by Tokyo Ohka Co., Ltd.) is applied again by spin coating to form a 10 μm-thick resist film, and the resist film is formed into a predetermined shape by masking, exposing and developing. Patterned. This pattern has no opening, and is patterned so as to cover the entire patterned Al film.

Then, the substrate is immersed in 50% hydrochloric acid at 60 ° C. to etch the portion of the ITO film where the resist film is not formed. Then, the resist film is also removed, and the transparent film made of the ITO film having a predetermined pattern is removed. A patterned substrate on which a conductive material 8 made of an Al film having an opening a formed on a light anode 7 was obtained.

As the conductive material 8, besides the Al film, a positive
In order to sufficiently prevent the flow of electrons into the interface with the hole transport layer 9
Al / Ti film, Al / W film with high work function and film thickness,
A laminated film of a conductive material such as a Ti / Au / Ti film may be used.
Chair or Al / AlN film, Al / Al_TwoO_ThreeFilm, Al
/ TiO_TwoFilm, Al / SiO_TwoFilm, Ti / Au / TiO _Two
Laminated films of conductive and insulating materials such as films
Alternatively, a stacked film of a conductive material and an insulating organic material may be used.

Next, this patterning substrate was subjected to ultrasonic cleaning for 5 minutes with a detergent (Semico Clean, manufactured by Furuuchi Chemical Co., Ltd.), ultrasonic cleaning for 10 minutes with pure water, and over 1% by volume of aqueous ammonia. After performing a cleaning process in the order of ultrasonic cleaning for 5 minutes using a mixed solution of hydrogen oxide water 1 and water 5 and ultrasonic cleaning for 5 minutes using pure water at 70 ° C., moisture attached to the substrate is removed with a nitrogen blower. It was further heated and dried.

Next, a Cr ₂ O ₃ (chromium oxide) film serving as the separation layer 12 is formed to a thickness of 1 to 2 μm on the patterning substrate by sputtering, and a resist material is applied by a spin coating method to a thickness of 10 μm. Forming a resist film of
The resist film was patterned into a predetermined shape by masking, exposing, and developing. Next, by immersing the substrate in an etchant to the ammonium persulfate as a main, after a Cr ₂ O ₃ film in a portion where the resist film is not formed is etched, the resist film is also removed, the predetermined pattern Cr ₂ A patterned substrate made of an O ₃ film was obtained.

Next, this patterning substrate was subjected to ultrasonic cleaning with a detergent (Semico Clean, manufactured by Furuuchi Chemical Co., Ltd.) for 5 minutes, ultrasonic cleaning with pure water for 10 minutes, and 1 part of ammonia water (by volume). After performing a cleaning process in the order of ultrasonic cleaning for 5 minutes using a mixed solution of hydrogen oxide water 1 and water 5 and ultrasonic cleaning for 5 minutes using pure water at 70 ° C., moisture attached to the substrate is removed with a nitrogen blower. It was further heated and dried.

Next, TPD was deposited on the anode-side surface of the patterning substrate as a hole transport layer 9 using a dedicated pattern mask in a resistance heating vapor deposition element reduced to a vacuum of 2 × 10 ⁻⁶ Torr or less. It was formed with a thickness of about 50 nm.
Further, the hole transport layer 9 is continuously formed in the resistance heating evaporation apparatus.
Alq ₃ was formed as a light emitting layer 10 on the upper surface with a thickness of about 60 nm. The deposition rates of TPD and Alq ₃ were both 0.2 nm / s.

Next, continuously in a resistance heating evaporation apparatus,
The cathode 11 was formed to a thickness of 300 nm on the light-emitting layer 10 using an Al-Li alloy containing 15 at% Li as an evaporation source.

Next, Al was formed to a thickness of 800 nm to 1 μm as the connection electrode 14 using a dedicated pattern mask.
Thereby, the translucent anode 7, the conductive material 8, and the driver IC
4 can be connected by wire debonding.

Thereafter, a sealing glass substrate separately prepared as the sealing material 13 was bonded and fixed on the organic EL element array 2 thus prepared by using a UV curable resin as an adhesive. Here, the organic layers of the hole transport layer 9 and the light emitting layer 10 were sealed so as not to be deteriorated by the surrounding environment (particularly moisture).

In this manner, the organic E as shown in FIG.
An L element array 2 was created.

Thereafter, the prepared organic EL element array substrate 3 was placed on the drive circuit substrate 1 on which the driver IC 4 was mounted, and fixed using positioning pins and an adhesive. And
Connection electrode 1 between driver IC 4 and organic EL element array
4. The cathode 11 was connected by wire bonding.

As described above, the exposure apparatus shown in the first embodiment was manufactured.

Next, the operation of the present exposure apparatus will be described.

As shown in FIG. 1, each terminal of the driver IC 4 is electrically connected to the light emitting dot 15 of the organic EL element array. When the terminal of the driver IC 4 outputs an ON signal as print data, the corresponding light emitting dot 15 is turned on via the bonding wire. Since the terminal to which the ON signal is not output indicates that the OFF signal is output, the corresponding light emitting dot 15 is not turned on. In this way, ON / OFF of the light emitting dot can be controlled.

Each of the light emitting dots 15 is wire-bonded to the driver IC 4 by the translucent anode 7 and the connection electrode 14. Also, a common cathode 11 as the cathode side
The cathode 11 is wire-bonded to the drive circuit board.

Since the light emitting dot area is defined by the conductive material 8 made of an Al film having a low work function, a potential barrier due to a work function difference is formed in the hole transport layer 9 so that electrons do not flow. That is, no light is emitted from the light emitting layer 10 located on the Al film. Therefore, the emitted light can efficiently pass through the opening a, and an improvement in light extraction efficiency can be expected.

The connection electrode 1 is made of a conductive material 8.
4 can be electrically connected with low resistance, so that the resolution is increased and the line width in the signal transmission direction from the driver IC 4 to the light-transmitting anode 7 is reduced. Since 8 is a low-resistance metal, the connection resistance of the entire array to the driver IC 4 can be greatly reduced.

As described above, an exposure apparatus equipped with an organic EL element array which can be driven with low power consumption was manufactured.

(Example 2) A glass substrate was used as the organic EL element array substrate 3, Au (gold) serving as the light reflection layer 17 was applied to the entire surface of the substrate by electron beam evaporation, and then the entire surface of the substrate was sputtered. Film thickness 1 to become translucent anode 7
A 60 nm ITO film was formed. A resist material (OFPR-800, manufactured by Tokyo Ohka Co., Ltd.) is applied on the ITO film by spin coating to form a resist film having a thickness of 10 μm.
The resist film was patterned into a predetermined shape by masking, exposing, and developing.

Next, this substrate was immersed in 50% hydrochloric acid at 60 ° C. to remove the IT film where the resist film was not formed.
The O film was etched first, and then immersed in a 5% potassium iodide solution at room temperature to etch the Au film. Then, the resist film is removed, the resist material is applied again, masked, exposed, and developed again to pattern the resist film into a predetermined shape, and immersed in 50% hydrochloric acid at 60 ° C. to form the resist film. The unexposed portion of the ITO film resist film was also removed to obtain a patterned substrate on which an anode composed of an ITO film and an Au film having a predetermined pattern was formed.

Next, this patterned substrate was subjected to ultrasonic cleaning for 5 minutes with a detergent (Semico Clean, manufactured by Furuuchi Chemical Co., Ltd.), ultrasonic cleaning for 10 minutes with pure water, and over 1% aqueous ammonia (by volume). After performing a cleaning process in the order of ultrasonic cleaning for 5 minutes using a mixed solution of hydrogen oxide water 1 and water 5 and ultrasonic cleaning for 5 minutes using pure water at 70 ° C., moisture attached to the substrate is removed with a nitrogen blower. It was further heated and dried.

Next, a Cr ₂ O ₃ (chromium oxide) film serving as the separation layer 12 is formed to a thickness of 1 to 2 μm on the patterning substrate by sputtering, and a resist material is applied by a spin coating method to a thickness of 10 μm. Forming a resist film of
The resist film was patterned into a predetermined shape by masking, exposing, and developing.

Next, this substrate was immersed in an etchant mainly composed of ammonium persulfate to etch the Cr ₂ O ₃ film where the resist film was not formed, and then the resist film was also removed. A patterned substrate made of a Cr ₂ O ₃ film was obtained.

Next, this patterning substrate was subjected to ultrasonic cleaning for 5 minutes with a detergent (Semico Clean, manufactured by Furuuchi Chemical Co., Ltd.), ultrasonic cleaning for 10 minutes with pure water, and excess with respect to 1 aqueous ammonia (volume ratio). After performing a cleaning process in the order of ultrasonic cleaning for 5 minutes using a mixed solution of hydrogen oxide water 1 and water 5 and ultrasonic cleaning for 5 minutes using pure water at 70 ° C., moisture attached to the substrate is removed with a nitrogen blower. It was further heated and dried.

Next, TPD was deposited on the anode-side surface of the patterning substrate as a hole transport layer 9 using a dedicated pattern mask in a resistance heating evaporation element in which the degree of vacuum was reduced to 2 × 10 ⁻⁶ Torr or less. It was formed with a thickness of about 50 nm.
Further, the hole transport layer 9 is continuously formed in the resistance heating evaporation apparatus.
Alq ₃ was formed as a light emitting layer 10 on the upper surface with a thickness of about 60 nm. The deposition rates of TPD and Alq ₃ were both 0.2 nm / s. Next, in a resistance heating vapor deposition apparatus, A containing 15 at% of Li was formed on the light emitting layer 10.
A light-transmissive cathode 11a is formed to a thickness of 2 to 10 nm using an l-Li alloy as an evaporation source, and an ITO film is
Transparent cathode 1 having a thickness of 500 nm and having translucency
1a was formed.

A light-reflecting layer 17 is provided below the light-transmitting anode 7, and a light-transmitting electrode is stacked on a metal material having a low work function and having a light-transmitting property by forming a thin film as a cathode. By using the film for the translucent cathode 11a, light can be emitted in the direction of the translucent cathode 11a.

The light reflecting layer 17 may be provided on the substrate 3, inside the translucent anode 7, or on the translucent anode 7. Since light does not pass through the inside of the organic EL element array substrate 3 in this extraction direction, there is no deterioration in light quantity due to reflection of light at the interface between the organic EL element array 2a and the organic EL element array substrate 3, and light emission More light can be taken out.

Next, in a separate chamber, in a resistance heating evaporation apparatus reduced to a degree of vacuum of 2 × 10 ⁻⁶ Torr or less, using a special pattern mask, Au as the connection electrode 14 was set to a predetermined thickness of 800 nm to 1 μm. A film was formed at the position.

Then, as shown in FIG. 9, a connection electrode 14 is formed in a pattern on the light reflection layer 17 drawn out as a wiring to electrically connect the light reflection layer 17, the translucent anode 7 and the connection electrode 14 to each other. After the connection, a sealing glass substrate separately prepared as the sealing material 13 was bonded and fixed onto the organic EL element array substrate 3 thus prepared using a UV curable resin as an adhesive. Here, the organic layers of the hole transport layer 9 and the light emitting layer 10 were sealed so as not to be deteriorated by the surrounding environment (particularly moisture).

In this manner, an organic EL element array having a cross section along the line CC ′ and the line DD ′ in FIGS. 8 and 9 was prepared.

Thereafter, as shown in FIG. 6, the prepared organic EL element array substrate 3 was placed on the drive circuit substrate 1 on which the driver IC 4 was mounted, and fixed using positioning pins and an adhesive. Then, the driver IC 4 and the connection electrode 14 and the cathode 11 of the organic EL element array 2 were connected by wire bonding.

As described above, the organic EL element array 2a in which the light emitting dots 16 were defined by the light-transmitting anode 7, the separation layer 12, and the light-transmitting cathode 11a, could be manufactured.

As described above, such organic E
The drive current can be reduced by the L element array 2a, and an exposure apparatus equipped with a low power consumption organic EL element array can be manufactured.

Embodiment 3 FIG. 5 shows an example of an image forming apparatus using the exposure apparatuses of Embodiments 1 and 2.

Rotary drum type photosensitive member 6 as image carrier
Around the charger 19, the exposure device 20, the developing device 22,
A transfer unit 23, a cleaner 26, and a static eliminator 27 are arranged.

The exposure apparatus 20 is provided with the organic EL element arrays 2 and 2
a, and a driving circuit 1 for driving the organic EL element array substrate 3, and a positive D
When the C voltage is applied, the energized light emitting dots 15, 16
Emits green light, and is imaged on the photoreceptor 6 through a focusing rod lens array 6 such as a selfoc lens.

The image forming apparatus includes a transfer unit 23 for transferring a toner image to a recording sheet 24 and a fixing unit 25 for fixing the transferred toner image to the recording sheet 24.

In such an image forming apparatus, the surface of the photoreceptor 6 is uniformly charged using the charger 19.

Then, an exposure light beam 21 from an exposure device 20 having the organic EL element arrays 2 and 2a is formed on a charged surface of the photoreceptor 6 through a selfoc lens or the like (exposure) to form a latent image. Is formed. That is, exposure corresponding to a time-series digital signal of target image information is performed on the charged surface, and an electrostatic latent image corresponding to the image information is formed.

Then, the electrostatic latent image is developed as a toner image by the developing device 22 using the insulating toner. On the other hand, the recording paper 24 is introduced at a predetermined timing into the transfer portion of the transfer device 23 which is brought into contact with the photoreceptor 6 with a predetermined pressing force, and the transfer is performed by applying a predetermined transfer bias voltage. As a result, the recording paper 24 to which the toner image has been transferred is separated from the surface of the photoreceptor 6 and introduced into a fixing device 25 such as a heat fixing system, where the toner image is fixed and printed.

At the same time, the residual toner is cleaned by the cleaner 26 and the residual potential is removed by the charge remover 27, thereby completing one printing process.

[0113]

As described above, according to the present invention, a light emitting dot can be easily formed in an arbitrary size, and an organic EL element array with good light emitting efficiency and low power consumption is mounted. And an image forming apparatus using the same.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an exposure apparatus according to a first embodiment of the present invention.

FIG. 2 is a plan view showing an organic EL array substrate in the exposure apparatus of FIG.

FIG. 3 is a sectional view taken along line A-A ′ of FIG. 2;

FIG. 4 is a sectional view taken along line B-B ′ of FIG. 2;

FIG. 5 is a schematic diagram illustrating an image forming apparatus using the exposure apparatus of FIG. 1;

FIG. 6 is a perspective view showing an exposure apparatus according to a second embodiment of the present invention.

FIG. 7 is a plan view showing an organic EL array substrate in the exposure apparatus of FIG. 6;

8 is a sectional view taken along the line C-C 'of FIG.

9 is a sectional view taken along line D-D 'of FIG.

FIG. 10 is a perspective view showing a conventional organic EL element array substrate and external circuit terminals.

11A is a cross-sectional view showing an enlarged main part of FIG. 10; FIG. 11B is a cross-sectional view showing an enlarged S portion of FIG. 11A;

FIG. 12 is a perspective view showing a basic configuration example of an organic EL element.

[Explanation of symbols]

 Reference Signs List 1 drive circuit board 2, 2a, 50 organic EL element array 3 organic EL element array substrate 4 driver IC 5 focusing rod lens array 6 photoreceptor 7, 62 translucent anode 8 conductive material 9, 63 hole transport layer 10 , 64 Light-emitting layer 11, 65 Cathode 11a Translucent cathode 12 Separation layer 13 Sealing material 14 Connection electrode 15, 16 Light-emitting dot 17 Light reflection layer 19 Charger 20 Exposure device 21 Exposure light beam 22 Developing device 23 Transfer device 24 Recording Paper 25 Fixing device 26 Cleaner 27 Static eliminator 51 Translucent substrate 52 ITO transparent electrode layer 53 Gold electrode layer 54 Organic compound layer 55 Cathode layer 56 Light emission hole 57 External circuit terminal 58 Wire 61 Glass substrate a Opening A, B Light emission point

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H05B 33/12 B41J 3/21 L 33/14 33/24 (72) Inventor Takahiro Komatsu Kadoma, Osaka Pref. 1006 Kadoma, Matsushita Electric Industrial Co., Ltd. DA01 DB03 EB00

Claims (3)

[Claims] 1. A conductive material formed on a translucent anode and having an opening for exposing the translucent anode, a hole transport layer for injecting holes into the translucent anode, and the opening A light-emitting layer formed so as to cover the portion and emitting light at the position of the opening;
And an organic EL element array substrate having an organic EL element array formed on the light emitting layer and including a cathode for injecting electrons, and a driver IC for driving the organic EL element array; An exposure apparatus comprising dots. 2. A hole transport layer for injecting holes into a translucent anode,
An organic EL element array substrate including an organic EL element array including a light emitting layer that emits light by the translucent anode into which holes are injected, and a cathode formed on the light emitting layer and injecting electrons; A driver IC for driving an element array; and a light reflection layer for reflecting light toward the organic EL element array substrate is provided between the organic EL element array substrate and the translucent anode. An exposure apparatus comprising: 3. An image forming apparatus using the exposure apparatus according to claim 1.