JP2000082720A - Light emitting device, aligner and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform an array structure with high accuracy by providing a plurality of light emitting elements constituted by sandwiching a plurality of organic compound layers between an anode layer and a cathode layer on a substrate, and mounting a driving IC for driving the elements in a flip-chip method. SOLUTION: Anodes 2 are patterned in individual electrodes corresponding to respective pixels and formed in an array state on a substrate 1 of a predetermined length. An organic compound layer 3 is laminated on an entirety of aligning array of the anodes 2, and further cathodes 4 are laminated. The layer 3 is sandwiched between the anodes 2 and the cathodes 4, connected above and below a film layer, and functioned as light emitting elements. An insulating moistureproof material is laminated on its surface to form a protective layer 5, then an aligning row of terminals 60 of driving IC 6 is connected to an aligning row of terminals 20 of the anodes 2, and mounted in a flip-chip method. Thus, an array structure with a high accuracy can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting device used for an electrophotographic apparatus such as a display, a copying machine, a printer, and the like.
The present invention relates to an exposure device and an image forming device.

[0002]

2. Description of the Related Art Conventionally, a laser beam system, an LED array system, and the like have been mainly used as an exposure system for writing a latent image on a photosensitive member.

[0003] However, in the case of the laser beam system, optical components such as a polygon mirror and a lens are required, so that it is difficult to reduce the size of the apparatus, and it is difficult to increase the speed.

[0004] In the case of the LED array system, since the substrate is expensive and an array cannot be formed with one substrate, it is necessary to arrange the cut chips. At that time, steps and intervals between chips become problems.

In addition, each LED (light emitting portion) on the chip,
Since both terminals of each of the corresponding driving ICs are connected by wire bonding, an enormous number of wire bondings are required, and there is a problem that the production becomes complicated and the production cost is raised.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems and to provide a light emitting device, an exposing device and an image forming device which are high-speed, compact, low-cost and high-definition.

[0007]

That is, the present invention provides a light emitting device comprising at least an anode layer, a cathode layer, and one or more organic compound layers sandwiched between them on a substrate. For driving a light emitting element
Are mounted by a flip-chip method, and an image forming apparatus having at least a light emitting device, an exposure device, and an exposure device, and a photoconductor exposed by the exposure device.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the light emitting device and the exposure device according to the present invention will be described with reference to the accompanying drawings.

FIGS. 1 to 3 show a first embodiment of the present invention. FIG. 1 is a sectional view of a light emitting device and an exposure apparatus according to the present invention, and FIG. FIG. 3 is a plan view showing another example of the arrangement pattern of the anode.

As shown in FIG. 1, a light emitting device and an exposure device according to the present invention comprise a light transmitting substrate 1, an anode 2, an organic compound layer 3, a cathode 4, a protective film 5, a driving film For I
C6 is provided.

In the manufacture, as shown in FIG. 2, first, on a substrate 1 having a predetermined length, anodes 2 are patterned into individual electrodes corresponding to respective pixels and formed in rows [FIG.
(A)]. An organic compound layer 3 is laminated on the entire row of the anodes 2 [FIG. 2 (b)], and a cathode 4 is further laminated [FIG. 2 (c)]. As a result, the organic compound layer 3 is sandwiched between the anode 2 and the cathode 4 and connected above and below the film layer to function as a light emitting element. In addition, by forming the anode 2 into a predetermined pattern in this manner, the formation of the organic compound layer 3 which is relatively weak to water, a solvent and heat becomes easy.

Then, in order to protect the surface layer of the organic light-emitting element, prevent deterioration and prevent short-circuiting of the electrodes, an insulating moisture-proof material is laminated on the surface to form a protective layer 5 [FIG.
(D)]. At this time, since the terminal portion 20 of the anode 2 is connected to the terminal portion (60) of the driving IC (6) in the next step, it is patterned so as not to cover the protective layer 5 but to expose it.

The arrangement pattern of the anode 2 is shown in FIG.
As shown in FIG. 3 (a), the terminal portions 20 may be simply arranged in a single row pattern, or as shown in FIG. 3, a staggered pattern arranged in two stages before and after zigzag may be used.
Thereby, the bonding area with the bump can be secured, and the density can be further increased.

After forming the protective layer 5, the terminal 2 of the anode 2
The array of terminal portions 60 of the driving IC 6 is connected to the array of 0s and mounted [FIG. 2 (e)]. This driving IC 6
The number of drive chips corresponding to the number of rows of the terminal portions 20 of the anode 2, that is, the number of pixels corresponding to the total number of pixels is housed in a single package having a length corresponding to the substrate 1.
Are formed corresponding to the rows of the terminal portions 20 of the anode 2.

As the substrate 1, any material can be used as long as the light emitting element can be formed on the surface. For example, it is preferable to use a transparent insulating substrate such as a glass such as soda lime glass or a resin film.

As a material of the anode layer 2, a material having a large work function is desirable. For example, ITO, tin oxide, gold, platinum, palladium, selenium, iridium, copper iodide and the like can be used. On the other hand, it is desirable that the material of the cathode layer 4 has a small work function, for example, Mg / Ag, Mg, A
1, In, or an alloy thereof can be used.

The organic compound layer 3 may have a single-layer structure or a multi-layer structure. For example, the organic compound layer 3 may have a hole transport layer into which holes are injected from the anode layer 2 and an electron transport layer from the cathode layer 4. Is injected, and one of the hole transport layer and the electron transport layer becomes the light emitting layer. Further, a phosphor layer containing a phosphor may be provided between the hole transport layer and the electron transport layer. In addition, the hole transport layer, the electron transport layer,
A configuration also serving as a fluorescent layer is possible.

As the hole transport layer, for example, N, N'-
Bis (3-methylphenyl) -N, N'-diphenyl-
(1,1′-biphenyl) -4,4′-diamine (TPD) can be used, and the following organic materials can also be used.

[0019]

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[0020]

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[0021]

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[0022]

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[0023]

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As the electron transporting layer, for example, Tris (8
-Quinolinol) aluminum (hereinafter Alq ₃ ), and the following materials can also be used.

[0025]

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[0026]

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[0027]

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[0028]

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Further, a dopant as shown below can be doped into the electron transporting layer or the hole transporting layer.

[0030]

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Preferably, a dielectric layer is provided between the anode layer 2 and the substrate 1. The dielectric layer can increase (lower) the reflection transmittance at a specific wavelength by laminating layers having different refractive indexes such as SiO ₂ and SiO. Alternatively, it is also possible to simply use a half mirror.

The driving IC 6 is mounted by, for example, a flip chip method using solder bumps and an anisotropic conductive adhesive material (anisotropic conductive paste and film).

For example, when the chip size is 2 mm × 10 mm using a combination of an Al substrate and a Si chip, the bump size is 70 μm □, and the number of arrays is 330, the condition for joining with solder is that the tool temperature is 400 ° C. The substrate temperature is preferably about 200 to 220 ° C., the pressure is preferably 15 kgf, and the time is preferably 60 sec.

However, since the organic compound layer 3 is crystallized and deteriorated under high temperature and high heat, the temperature condition should be reduced as much as possible. In that respect, when the anisotropic conductive paste is used, even if the organic compound layer 3 has a relatively low heat resistance, the driving IC
6 can be implemented. That is, as a condition for joining with the anisotropic conductive paste, the tool temperature is 200 ° C.
The substrate temperature is relatively low, about 130 to 140 ° C., the pressure is preferably 15 kgf, and the time is preferably 60 sec.

In addition, as long as there is little thermal problem, an anisotropic conductive film can be used instead of the anisotropic conductive paste. The conditions for joining with this anisotropic conductive film are that the tool temperature is 350 ° C. and the substrate temperature is about 180 °.
It is preferable that the pressure is 15 kgf and the time is 60 sec. Further, as long as there is no thermal problem, the above-mentioned solder may be used.

Although the solder and the anisotropic conductive adhesive are mentioned here, any material may be used as long as it can conduct electricity.

With the above configuration, the light emitting device of the present embodiment has an anode 2 formed on a substrate 1 of a predetermined length in an array of individual electrodes corresponding to each pixel, and an organic compound on the entire array. Since the layer 3 is laminated, each anode 2
The organic compound layer 3 is sandwiched between the anode 2 and the cathode 4 and connected above and below the film layer to form a plurality of arrays. Then, a driving IC 6 for driving the organic compound layer 3 is mounted on the row of the terminal portions 20 of the anode 2 by a flip-chip method, thereby functioning as a light emitting device and an exposure device.

As described above, since the organic compound layer 3 is laminated on the row of the anodes 2 at a time, the production is simple and easy, the productivity is excellent, and the production cost can be kept low.

Since the driving ICs 6 are mounted on the array of the anodes 2 by the flip-chip method, an enormous number of wire bondings as in the prior art are not required, and the manufacturing is simple and easy, and the productivity is excellent. Production costs can be reduced.

Further, since the organic compound layers 3 are collectively laminated, the uniformity of the film layers is inevitably increased, and a highly accurate arrangement structure can be obtained. As a result, a high resolution is obtained, and it can be preferably applied to an electrophotographic exposure unit.

FIG. 4 shows a second embodiment of the present invention, in which the same components as those in the above-described first embodiment are denoted by the same reference numerals, and redundant description will be omitted.

Here, the driving IC 6 is mounted with its orientation changed, that is, the driving IC 6 has its terminal portion 60 connected to the terminal portion 20 of the anode 2, but at this time, the element surface is protected. It is mounted on the film 5 so as to be in face-to-face contact.

In this case, the element surface of the driving IC 6 is in a state of covering the organic compound layer 3, so that the luminescent heat of the organic compound layer 3 is transmitted to the driving IC 6 package and radiated. Further, deterioration of the light emitting element due to heat can be suppressed.

FIG. 5 shows a third embodiment of the present invention, in which the same components as those in the above-described first embodiment are denoted by the same reference numerals, and redundant description will be omitted.

Here, the driving IC 6 is connected to the second
As in the embodiment, the package is mounted with the package surface facing the protective film 5 so as to face each other.
The radiation fins 7 are mounted on the fins.

As described above, since the radiation fins 7 are mounted on the driving IC 6, not only can the thermal degradation of the light emitting element be suppressed, but also the temperature rise of the driving IC 6 can be suppressed, and the radiation efficiency can be increased. .

FIG. 6 shows a schematic configuration diagram of an image forming apparatus using an electrophotographic method as an example of the image forming apparatus of the present invention.

Reference numeral 111 denotes an electrophotographic photosensitive member of a rotating drum type as an image carrier, 112 denotes a charging device, 113 denotes a developing device, 114 denotes a transfer device, 115 denotes a fixing device, and 116 denotes a cleaning device.

As the light source L, the exposure apparatus (not shown) of the present invention is used. A driving driver is connected to the exposure apparatus, and when a positive voltage is applied to the anode layer and a negative voltage is applied to the cathode layer to apply a DC voltage, green light is emitted from the light emitting unit, and an image can be formed on the photoconductor 111. Good images can be obtained.

The photosensitive member 111 is uniformly charged by the charging device 112. Exposure L is performed by an exposure device in accordance with a time-series electric digital pixel signal of target image information output to the charged surface of the photoconductor 111, and the photoconductor 111
An electrostatic latent image corresponding to the target image information is formed on the peripheral surface of. The electrostatic latent image is developed as a toner image by a developing device 113 using insulating toner. On the other hand, a transfer material p as a recording material is supplied from a paper feeding unit (not shown),
The photoconductor 111 is introduced at a predetermined timing into a pressure contact nip (transfer portion) T between the photoconductor 111 and a contact transfer unit contacted with a predetermined pressing force, and performs a transfer by applying a predetermined transfer bias voltage. .

The transfer material P to which the toner image has been transferred is separated from the surface of the photoreceptor 111 and is fixed by a fixing device 1 such as a heat fixing method.
15, the toner image is fixed, and is discharged out of the apparatus as an image-formed product (print). Transfer material P
After the transfer of the toner image, the surface of the photoreceptor is cleaned by a cleaning device 116 to remove adhered contaminants such as residual toner and is repeatedly provided for image formation.

[0052]

As described above, according to the present invention,
It is simple and easy to manufacture, has excellent productivity and can keep production costs low.

Then, with respect to the row of the terminal portions of the anode,
Since the driving IC for driving the organic compound layer is mounted by the flip-chip method, an enormous number of wire bondings are not required unlike the related art, and the manufacturing is simple and easy, the productivity is excellent, and the production cost can be reduced. .

Further, since the organic compound layers are collectively laminated, the uniformity of the film layers is inevitably increased, and a highly accurate array structure can be obtained. As a result, a high resolution is obtained, and it can be preferably applied to an electrophotographic exposure unit.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment of the present invention.

FIG. 2 is a plan view and a cross-sectional view for sequentially explaining manufacturing steps of the light emitting device and the exposure device of FIG.

FIG. 3 is a plan view showing another example of an arrangement pattern of anodes.

FIG. 4 is a sectional view showing a second embodiment of the present invention.

FIG. 5 is a sectional view showing a third embodiment of the present invention.

FIG. 6 is a configuration diagram illustrating an example of the image forming apparatus of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Anode 3 Organic compound layer 4 Cathode 5 Protective film 6 Driving IC 7 Radiation fin 20, 60 terminal part

Claims (13)

[Claims] 1. A driving device for driving a light-emitting element, comprising a substrate and a plurality of light-emitting elements each including at least an anode layer and a cathode layer and one or more organic compound layers sandwiched therebetween. A light-emitting device in which an IC is mounted by a flip-chip method. 2. The method according to claim 1, wherein the anode is an individual electrode formed of a translucent conductive material, and at least a part of the electrode of the driving IC is connected to each of the individual electrodes. A light-emitting device according to claim 1. 3. The light emitting device according to claim 1, wherein the driving IC is mounted with an anisotropic conductive paste. 4. The light emitting device according to claim 1, wherein the driving IC is mounted with an anisotropic conductive film. 5. The light emitting device according to claim 1, wherein the driving IC is mounted so as to cover each light emitting element. 6. The light emitting device according to claim 1, further comprising a heat radiation fin provided on the driving IC. 7. A driving device for driving a light emitting element, comprising a plurality of light emitting elements each including at least an anode layer and a cathode layer and one or more organic compound layers sandwiched between them on a substrate. An exposure apparatus, wherein the IC is mounted by a flip chip method. 8. The method according to claim 7, wherein the anode is an individual electrode formed of a translucent conductive material, and at least a part of the electrode of the driving IC is connected to each of the individual electrodes. 3. The exposure apparatus according to claim 1. 9. The exposure apparatus according to claim 7, wherein the driving IC is mounted with an anisotropic conductive paste. 10. The driving IC is mounted on an anisotropic conductive film.
3. The exposure apparatus according to claim 1. 11. The exposure apparatus according to claim 7, wherein the driving IC is mounted so as to cover each light emitting element. 12. The exposure apparatus according to claim 7, wherein a radiation fin is provided on the driving IC. 13. An exposure apparatus according to claim 7, wherein:
An image forming apparatus comprising at least a photoconductor exposed by the exposure apparatus.