JPH0437248A - Light emitting element device and manufacture of light emitting element device and picture reader - Google Patents

Abstract

PURPOSE:To inexpensively manufacture a thick film EL light emitting element device by arranging a light emitting element forming section with a light emitting layer by two electrodes inbetween and a transparent part through which a light is transmitted alternately. CONSTITUTION:Plural recessed parts 2 are formed periodically in the lengthwise direction of a transparent substrate 1, a light emitting element forming part 3 is provided in each recessed part 2 and the light emitting element forming part 3 and a transparent part 4 through which a light is transmitted are arranged alternately. A transparent electrode 5, a light emitting layer 6 formed by forming a film to a resin with light emitting particles scattered therein by the thick film process, a dielectric layer 7 and a metallic electrode 8 are laminated sequentially on each recessed part 2, and when an AC voltage is applied between the transparent electrodes 5 with the light emitting layer 6 inbetween and the metallic electrode 8, a light is emitted from the light emitting layer 6 when the polarity is changed. Thus, the light emitting element device is manufactured inexpensively by the thick film process.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a light emitting element device used in an image processing unit such as a facsimile machine or an image scanner. The present invention relates to a light emitting device to be formed, a method for manufacturing the same, and an image reading device.

(Prior Art) In recent years, in order to miniaturize image reading devices, solid-state light sources such as electroluminescent (EL light emitting) elements are used instead of fluorescent lamps, and the light emitting elements and light receiving elements are integrated. Something has been proposed.

This type of image reading device prevents uneven illuminance by irradiating the document surface at right angles to the document surface, and also reduces the optical path length of the light reflected from the document surface entering the light emitting element. In order to shorten the length, for example, as shown in FIGS. 4 and 5, an EL light emitting element device 40 is placed directly above a light receiving element array 30 having light receiving elements 31 arranged in a line with an adhesive 50 interposed therebetween. ing. Then, a light transmitting portion 60 is formed in the EL light emitting device device 40 at a position corresponding to each light receiving element 31, so that reflected light 80 from the document surface 7° is guided to each light receiving element 31 through this light transmitting portion 60. It has become.

The light-transmitting portion 60 of the EL light emitting element assembly ft40 is configured as follows. That is, a transparent electrode 42. is formed on a transparent substrate 41 using a thin film process. Insulating layer 43, light emitting layer 44.
An insulating layer 45 is deposited, and a metal electrode 46 is deposited and patterned by etching to have a rectangular opening 46a.

Transparent electrode 42. Since the insulating layer 431 and the light emitting layer 44 are both formed of light-transmitting materials, the portion located above the opening 46a provided in the metal electrode 46 becomes the light-transmitting portion 60.

(Problems to be Solved by the Invention) However, according to the above structure, since a thin film type EL light emitting element is used, the manufacturing cost is high, and the EL light emitting element is There was a problem in that the area was limited and it was difficult to obtain a large area.

On the other hand, there are also EL devices in which a luminescent layer is formed using a thick film process such as screen printing.This EL device eliminates the above-mentioned drawbacks, but the luminescent layer consists of luminescent particles such as ZnS in an organic binder. Since a dispersed material is used, the light reflected from the document surface is scattered in the light-emitting layer due to the difference in refractive index between ZnS and the organic binder, and cannot be transmitted efficiently. Therefore, when a thick film type EL light emitting element is used in an image reading device that integrates the light emitting element and the light receiving element described above, the light emitting layer portion on the light receiving element must also be removed. However, since the light emitting layer deposited by the thick film process is as thick as 10 to 100 μm, fine patterning is not possible. It could not be replaced.

The present invention has been made in view of the above-mentioned circumstances, and includes a thick film type EL light emitting element device that can be used in an image reading device that integrates a light emitting element and a light receiving element, a method for manufacturing the same, and a thick film type EL light emitting device. An object of the present invention is to provide an image reading device using a light emitting element device.

(Means for Solving the Problems) In order to solve the problems of the above-mentioned conventional example, a light emitting element device according to claim 1 includes a light emitting layer formed by forming a plurality of recesses in a transparent substrate and deposited by a thick film process, Two electrodes sandwiching the light emitting layer are laminated in each of the recesses, and a light emitting element forming part sandwiching the light emitting layer between the two electrodes and a transparent part through which light passes are arranged alternately. .

The method for manufacturing a light emitting device device according to claim 2 includes a recess forming step of forming a plurality of recesses on a transparent substrate by photolithography, and an electrode forming step of forming a band-shaped transparent electrode on the transparent substrate in which the recesses are formed. and a light emitting element forming step of laminating a light emitting layer formed by depositing a resin in which light emitting particles are dispersed in a thick film process, and a metal electrode located on the light emitting layer in the recess. .

The image reading device according to claim 3 includes a light emitting layer formed by depositing a resin in which light emitting particles are dispersed in a thick film process, and two layers sandwiching the light emitting layer.
two electrodes are stacked on a transparent substrate, and a light-emitting element forming part in which the light-emitting layer is sandwiched between two electrodes and a light-transmitting part through which light passes are provided alternately in the main scanning direction of the light-receiving element array. Each light-receiving element is arranged at a position corresponding to the part, and the light emitted from the light-emitting element forming part is reflected on the document surface arranged on the repulsion light element side of the transparent substrate, and the reflected light is transmitted through the light-transmitting part. The light is then incident on the light receiving element.

(Function) According to the light emitting element device of the first aspect, since a plurality of recesses are formed in the transparent substrate and the EL light emitting element is formed in the recesses, the recesses can be etched without etching the light emitting layer of the EL light emitting element. A light-transmitting part can be formed in between.

According to the method for manufacturing a light emitting element device according to claim 2, a plurality of recesses are formed in the transparent substrate and the EL light emitting element is formed in the recesses, so that the light emitting layer of the EL light emitting element can be attached by a thick film process. It can be membraned.

According to the image reading device of claim 3, the light-emitting element forming portions and the light-transmitting portions are provided alternately in the main scanning direction of the light-receiving element array, and each light-receiving element is disposed at a position corresponding to the light-transmitting portion. , reflected light from the document surface is guided to each light receiving element via the light transmitting section.

(Example) FIG. 1(g) shows an example of the light emitting device of the present invention.
This will be explained with reference to FIG. 2(a).

FIG. 1(g) is an explanatory cross-sectional view taken along line II' in FIG. 2(a).

This EL light emitting element device has a plurality of recesses 2 periodically formed in the longitudinal direction of a transparent substrate 1, a light emitting element forming part 3 is provided in each of these recesses 2, and light is connected to the light emitting element forming part 3. The transparent parts 4 that transmit light are arranged alternately. Each recess 2 has a transparent electrode 52 and a luminescent layer 6 formed by depositing a resin in which luminescent particles are dispersed using a thick film process. A dielectric layer 7. Metal electrodes 8 are sequentially laminated, and when an alternating current voltage is supplied between the transparent electrode 5 and the metal electrode 8 that sandwich the light emitting layer 6, light is emitted from the light emitting layer 6 when the polarity changes. Ru.

Next, a method for manufacturing this EL light emitting device will be described with reference to FIGS. 1(a) to 1(g).

A resist 10 is applied to the entire surface of a transparent substrate 1 made of glass or the like with a thickness of 100 μm (FIG. 1(a)), and patterned by exposure and development to remove the resist in the portion corresponding to the light emitting element forming portion. A resist pattern 10' is formed.

Next, using an etching solution such as hydrofluoric acid, the transparent substrate 1 below the resist removed portion is wet-etched to form a plurality of recesses 2 with a depth of 50 to 60 μm.
)), the resist pattern 10' is removed.

A transparent electrode 5 made of ITO or the like is deposited to cover the recess 2 by a spray blating method, a CVD method, or a physical vapor deposition method (FIG. 1(C)).

Alternatively, after forming the resist pattern 10', ITO or the like may be deposited (FIG. 1 (C-1)), and the transparent electrode 5 may be formed only in the recess 2 by a lift-off method (FIG. 1 (C-1)).
2) ).

Next, after applying the light emitting member 6a to the entire surface by screen printing or spray blating method (FIG. 1(d))
, the recess 2 is removed by scraper 11 or polishing.
A light-emitting layer 6 is formed excluding the film coated on other parts (
Figure 1(e)). The light emitting member 6a is made of ZnS:Cu, CI
ZnS: Cu, AI ZnS: Cu, Br Z
nS:Cu.

After classifying any of Mn, CI ZnCd5: Cu, Br, or a blend of two or more of these materials, acetal resin, epoxy resin, methyl methacrylate resin, polyester resin, cyanoethyl cellulose resin, fluorine resin, etc. Use one of these binder materials dispersed and mixed.

Additionally, low melting point glass, cyanoethyl xerose.

Vinylidene fluoride terpolymer, vinylidene fluoride
After coating the entire surface with a dielectric material such as trifluoroethylene copolymer, epoxy resin, silicone resin, etc. by a thick film process such as screen printing or spray blating, the above-mentioned material is removed using a scraper or polishing as in the previous step. The film coated on areas other than the concave portions 2 is scraped off to form a dielectric layer 7 (FIG. 1(f)).

Finally, a metal such as A1 is deposited on the entire surface by spray brating method, CVD method, physical vapor deposition method, etc.
A metal electrode 8 is formed by patterning by photolithographic etching so that a rectangular opening 8a is located above the convex portion of the transparent substrate 1, and the light emitting element forming portion 3 formed in each concave portion 2 and the above-mentioned The transparent parts 4 formed below the openings 8a are arranged alternately (FIG. 1(g))
.

FIG. 3 shows an example in which the above-described EL light emitting device is applied to an image reading device.

That is, the above-described EL light emitting element device and the light receiving element array 20 are integrated via the transparent adhesive 50. The EL light-emitting element device and the light-receiving element array 2 are arranged so that each of the light-receiving elements 20a, which are arranged in large numbers in the main scanning direction and forming the light-receiving element array 20, is located directly below the light-transmitting section 4 of the EL light-emitting element device.
0 is glued. The light-receiving element array 20 is formed on a substrate 21 so that its length corresponds to the document width, and each light-receiving element 20a has individual electrodes 22 made of chromium (Cr) formed discretely in the main scanning direction. , indium oxide
It has a thin film sandwich structure in which a band-shaped common electrode 24 made of tin (ITO) and a band-shaped photoconductive layer 23 made of amorphous silicon (a-5t) are sandwiched. In addition, the light receiving element is not limited to this, and CC
A light receiving element such as D may also be used.

50~ for the transparent electrode 5 and metal electrode 8 of the EL light emitting element device
When an AC voltage of about 250 V is applied, the light-emitting layer 6 sandwiched between the picture electrodes emits light, and the document surface 70 placed on the transparent substrate 1 is irradiated. The reflected light 80 from the document surface 70 passes through each light-transmitting section 4 and enters each light-receiving element 20a arranged directly below the light-transmitting section 4 to generate electric charge, which causes a drive IC (not shown) to generate a charge. Under control, each light receiving element outputs a signal to obtain image information.

According to the embodiment described above, since the light emitting layer 6 is formed in the recess 2 of the transparent substrate 1, the distance between the document surface 70 and the light receiving element 20a can be reduced, and the reflected light 80 from the document surface 70 can be reduced.
can be used efficiently. Furthermore, the light-emitting element forming portions 3 and the light-transmitting portions 4 are formed alternately to make the light-emitting portions discrete, and a specific light-emitting portion illuminates a specific document surface portion, so that the document surface 70 is uniformly illuminated. It does not generate unnecessary irradiation light compared to the case. Therefore, it is possible to prevent reflected light from a specific document surface from entering a light-receiving element adjacent to the light-receiving element to which it should originally enter, thereby reducing the proportion of unnecessary reflected light and improving resolution (MTF).

Furthermore, although the transparent substrate 1 and the metal electrodes 8 are etched by photolithography, other film deposition processes can be formed by normal thick film processes, so it is possible to form an inexpensive, large-area EL.
A light emitting element can be obtained.

Further, since the light emitting layer 6, which is sensitive to humidity, is buried in the recess 2 of the transparent substrate 1, an EL light emitting element that is less susceptible to external influences and has high reliability against environments can be obtained.

In this embodiment, an example of one line of light receiving elements and EL light emitting elements has been described, but in the case of a color image reading device, for example, multiple lines of the image reading devices described above are arranged in parallel, and each EL light emitting device is connected to the other. The MTF in the sub-scanning direction can be improved by shifting one bit at a time in the scanning direction and by arranging the light-emitting portions and the light-transmitting portions alternately in the sub-scanning direction as well.

(Effects of the Invention) As described above, according to the present invention, it is possible to obtain a light emitting element in which a light emitting layer can be deposited by a thick film process, so that a light emitting element device and an image reading device using the same can be manufactured at low cost. can do. Furthermore, in the thick film process, there is no restriction on the area of film deposition, so it is possible to increase the area of the light emitting device. Furthermore, since the light-emitting layer is formed within the recessed portion of the transparent substrate, a light-emitting element device with high environmental resistance and reliability can be obtained, and the entire device can be made thinner.

Further, according to the image reading device of the present invention, the light emitting element forming portions and the light transmitting portions are formed alternately to make the light emitting portions discrete, and the specific light emitting portions illuminate a specific document surface portion. Compared to the case where the document surface is uniformly irradiated, unnecessary irradiation light is not generated, and the ratio of unnecessary reflected light can be reduced and resolution (MTF) can be improved.

[Brief explanation of the drawing]

FIGS. 1(a) to (g) are process diagrams showing the manufacturing process of the light emitting device of the present invention, FIG. 2 is an explanatory plan view of the light emitting device of the present invention, and FIG. 3 is obtained from FIG. 1. A partially cross-sectional explanatory diagram of an image reading device using a light emitting element device, FIG. 4 is a plan view explanatory diagram of a conventional image reading device of a light emitting element-light receiving element integrated type, and FIG. 5 is a diagram taken along v-v' in FIG. It is a line cross-sectional explanatory drawing. 1...Transparent substrate 2...Recessed portion 3...Light emitting element forming portion 4...Transparent portion 5...Transparent electrode 6... ...Light emitting layer 7...Dielectric layer 8...Metal electrode 8a...Opening 20...Light receiving element array 70...Document surface 80...Reflected light Figure 1 Figure 2

Claims (3)

[Claims] (1) A plurality of recesses are formed in a transparent substrate, and a light emitting layer deposited by a thick film process and two electrodes sandwiching the light emitting layer are laminated in each recess, and the light emitting layer is placed between the two electrodes. 1. A light-emitting element device characterized in that a light-emitting element forming part sandwiched between two parts and a light-transmitting part through which light passes are arranged alternately. (2) A recess formation step in which a plurality of recesses are formed on a transparent substrate by photolithography, an electrode formation step in which a band-shaped transparent electrode is formed on the transparent substrate with recesses formed, and a resin in which luminescent particles are dispersed. A method for manufacturing a light emitting element device, comprising a light emitting element forming step of laminating a light emitting layer deposited by a thick film process and a metal electrode located on the light emitting layer in the recess. (3) A light emitting layer formed by depositing a resin in which luminescent particles are dispersed in a thick film process and two electrodes sandwiching the light emitting layer are laminated on a transparent substrate, and the light emitting layer is sandwiched between the two electrodes. Element forming parts and light transmitting parts through which light passes are provided alternately in the main scanning direction of the light receiving element array, each light receiving element is arranged at a position corresponding to the light transmitting part, and light is emitted from the light emitting element forming part. The image reading device is characterized in that the reflected light is reflected on a document surface disposed on a side of a repulsion light element of a transparent substrate, and the reflected light is transmitted through the light transmitting portion and enters the light receiving element.