JPH0453165A - Image read out device - Google Patents

Abstract

PURPOSE:To shield light being directly incident from a luminous layer to respective light receiving parts, for preventing an increase in dark output by making an EL. luminous element part of a peripheral guide s part of a light transmitting window, which guides luminous light from the EL, luminous element reflected on the manuscript surface to a light receiving element non-luminous. CONSTITUTION:An EL, luminous element 4 forms a transparent electrode 41 consisting of ITO or the like on an EL, substrate 11, and thereon an insulating layer 42 and a luminous layer 43 are formed, further thereon the insulating layer 42 and opaque electrodes 44, consisting of a metal are laminated in order. ITO or the like is not formed on the part of the transparent electrode 41 of the upper part of a light transmitting window 45, luminous light up to about 1mum on the left side from a luminous spot is incident directly on a light receiving element so that ITO or the like of the electrode 41 is not to be provided up to the inside not more than 1mum from the peripheral part of the window 45 so as to form a non-luminous part 46b. Accordingly, direct incident light being incident on each light receiving part of the light receiving element passing through a direct light transmitting window is shielded to prevent an increase in dark output of an image read out device.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an image reading device used in facsimiles, scanners, etc., and particularly relates to an image reading device that can prevent an increase in dark output.

(Conventional technology) Conventional facsimiles, scanners, etc. use EL as a light source.
There are devices that use light emitting elements, and in particular, ultra-compact image reading devices that integrate an EL light emitting element and a contact type image sensor have been proposed.

For example, as shown in the cross-sectional explanatory diagram of FIG.
It is constructed by bonding an EL light emitting element 4 formed on a substrate 11 with a transparent and insulating adhesive (adhesive layer 3), and is elongated in the horizontal direction (main scanning direction) in the figure. It is formed.

The light-receiving elements 2 are made of chrome (C) so that they are arranged on the substrate 1 in a plurality of discrete parts in the left-right direction (main scanning direction) in FIG.
r), etc., a band-shaped photovoltaic layer 22 formed of amorphous silicon (a-5t), and a band-shaped transparent electrode 23 formed of indium tin oxide (ITO). It is configured.

The EL light emitting element 4 has ITO1In, O
5. A transparent electrode 41 made of SnO3 etc. and Y,0
8, S i3 N, , BaTi0. An insulating layer 42 made of ZnS:Mn or the like, a light emitting layer 43 made of ZnS:Mn or the like, an insulating layer 42 made of the same as above, and an opaque electrode 44 made of metal such as aluminum (AI) are sequentially laminated. When a voltage is applied between the transparent electrode 4] and the opaque electrode 44, light is emitted from the light emitting layer 43 held between them, passes through the transparent electrode 41, and is irradiated onto the original 100. In other words, the light from the light emitting layer 43 is emitted from the surface side of the transparent electrode 4.

A rectangular light transmitting window 45 is opened in the opaque electrode 44 so as to correspond to each light receiving portion of the light receiving element 2, and the light emitting layer 4
3 is reflected by the original 100, and the reflected light passes through the light transmitting window 45 and irradiates the light receiving portion of the light receiving element 2 (Japanese Patent Laid-Open No. 5'1210664).
(see publication).

(Problems to be Solved by the Invention) However, the configuration of the conventional image reading device as described above has the following problems. These problems are explained in the seventh section.
Explain using diagrams.

First, the emitted light p from the light emitting layer 43 of the ELL optical element 4 is emitted from the surface side of the transparent electrode 41, irradiates the original 100, is reflected, and passes through the light transmitting window 45 to each of the light receiving elements 2. However, the emitted light q from the light emitting layer 43 in the peripheral area of the light transmitting window 45 directly passes through the light transmitting window 45 and enters each light receiving part of the light receiving element 2. Sometimes I put it away. Originally, it is desirable to receive only the reflected light of the emitted light p, but if the directly incident light q from the light emitting layer 43 is also received in this way, the dark output of the image reading device will increase. There was a problem.

Second, the emitted light r from the light emitting layer 43 of the EL destination element 4 is emitted from the surface side of the transparent electrode 41;
The emitted light r is not transmitted from the direction of the document 100, but is totally reflected on the surface of the ELL plate 11, and the total reflected light, /
In some cases, the light (the total reflection of the emitted light r) passes through the light transmitting window 45 and enters each light receiving portion of the light receiving element 2. If the total reflected light r' is also received in this way, there is a problem in that the dark output of the image reading device increases.

Third, the emitted light p from the light emitting layer 43 of the ELL optical element 4 is emitted from the surface side of the transparent electrode 41, and the emitted light p is transmitted from the ELL plate 11 toward the document 100.
Due to the difference in the refractive index of the glass of the plate 11 and the refractive index of the air where the original 100 is placed, some percentage of the emitted light p becomes surface reflected light S on the surface of the ELL plate 11, and the surface There have been cases where the reflected light S passes through the light transmission window 45 and enters each light receiving portion of the light receiving element 2. When the surface reflected light S is also received in this way, there is a problem in that the dark output of the image reading device increases.

The present invention has been made in view of the above-mentioned circumstances, and particularly solves the first problem of blocking the direct incident light that passes through the light-transmitting window from the light-emitting layer and directly enters each light-receiving portion of the light-receiving element. It is an object of the present invention to provide an image reading device which can prevent an increase in dark output of the image reading device.

(Means for Solving the Problems) In order to solve the problems of the conventional example, the present invention provides a light receiving element formed on a first substrate, a transparent electrode, a light emitting layer, and an opaque electrode on a second substrate. In an image reading device in which an ELL optical element having an ELL optical element is bonded such that the first substrate and the second substrate face outward, the emitted light from the ELL optical element is transferred to the second substrate on the side of the gray light receiving element. A light transmitting window is provided in the opaque electrode to guide the reflected light to the light receiving element after being reflected by the document surface disposed on the opposite side, and a non-transparent window is provided in which the ELL optical element portion around the light transmitting window does not emit light. It is characterized by the provision of a light emitting part.

(Function) According to the present invention, conventionally, there is direct incident light in which light emitted from a light emitting layer directly passes through a light transmission window and enters each light receiving portion of a light receiving element, increasing dark output. was, but
By providing a non-light-emitting portion around the light-transmitting window of the ELL optical element as in the present invention, direct incident light can be blocked, and an increase in dark output of the image reading device can be prevented.

(Example) An example of the present invention will be described with reference to the drawings.

FIG. 1 shows a cross-sectional explanatory view of the entire image reading device according to an embodiment of the present invention. Components having the same configuration as in FIG. 7 are given the same reference numerals.

The configuration of the image reading device of this embodiment is such that a light receiving element 2 formed on a substrate 1 made of glass, ceramic, etc. and an EL light emitting element 4 formed on an EL substrate 11 made of glass, etc. are transparent and insulated. The two are bonded together using a sterile adhesive (adhesive layer 3).

The structure of the light receiving element 2 is that individual electrodes 21 made of metal such as chromium (Cr) are formed on a substrate 1, a photoelectric conversion layer 22 made of amorphous silicon (a-3i) is formed on top of the individual electrodes 21, and Indium tin oxide (iTO)
) is formed.

Here, the lower individual electrodes 21 are formed by being discretely divided in the main scanning direction, and the transparent electrode 23 is formed as a strip-shaped common electrode, so that the photoelectric conversion layer 22 is separated from the individual electrodes 21 and transparent. The portion sandwiched between the electrodes 23 corresponds to each light receiving element 2.
A collection of them forms a light receiving element array.

Furthermore, the end portions of the discretely formed individual electrodes 21 are connected to a driving IC (not shown) so as to extract charges generated by the light receiving element 2. In addition, in the light receiving element 2, CdS is used instead of amorphous silicon.
It is also possible to use cadmium selenium (e) or the like as the photoelectric conversion layer 22.

The EL light emitting element 4 includes ITOlI n,
A transparent electrode 41 made of 03, SnO2, etc. is formed, and Si, N, , Sin, , Y are formed thereon.

An insulating layer 42 made of ZnS:Mn, etc. is formed next, and a light emitting layer 43 made of ZnS:Mn etc. is formed thereon.
and an opaque electrode 44 made of metal such as aluminum (AI) are sequentially laminated.

A rectangular light transmitting window 45 is opened in the opaque electrode 44 so as to correspond to each light receiving portion of the light receiving element 2, and the light emitting layer 4
The light emitted from the light receiving element 3 is reflected by the original 100, and the reflected light passes through the light transmitting window 45 and enters the light receiving portion of the light receiving element 2.

In addition, as shown in the enlarged cross-sectional view of the EL light emitting element in FIG. 2 and the plan view of the EL light emitting element in FIG.
In the transparent electrode 41 portion corresponding to the upper part of the transparent electrode 41
No ITO or the like is formed on the transparent electrode 41 portion above the peripheral portion of the light transmission window 45.
By not providing ITO or the like of the transparent electrode 41, the light transmitting window 45 portion is made into a non-light emitting portion 46a, and the peripheral portion of the light transmitting window 45 is also being made into a non-light emitting portion 46b.

Regarding the non-light-emitting portion 46b in the peripheral portion of the light-transmitting window 45, how far inward from the light-transmitting window 45 the non-light-emitting portion should be made will be explained using the orbit explanatory diagram of the EL emitted light in FIG. Figure 4 shows the trajectory of the emitted light when the emitted light is emitted from the light emitting layer at the center of the right end in the lower left direction. shall be.

In FIG. 4, approximately 4 μm to the left from the light emitting point is shown. Part a is the EL substrate 11, and parts b and d are the insulating layer 4.
2, portion C is the light-emitting layer 43, and the lower side of the drawing is the light-receiving element side. As you can see from Figure 4, about 1 minute to the left of the light emission point.
Since emitted light of up to 1 μm directly enters the light receiving element, the transparent electrode 4
] It is sufficient to form the non-light-emitting portion 46b without providing ITO or the like.

Therefore, the width L1 of the light transmission window 45 shown in FIG.
The distance between the light transmitting window 45 and the adjacent light transmitting window 4 is approximately 60 μm.
The width L2 to the edge of the light transmitting window 4 is approximately 125 μm.
The width L3 of the non-light-emitting portion 46b in the peripheral portion of No. 5 is approximately 3 to 4 μm.
It is appropriate to keep it at a certain level. The reason why the width L3 of the non-light emitting part 46b is set to about 3 to 4 μm is that when the light transmitting window 45 portion of the aluminum opaque electrode 44 is aligned with the part where the transparent electrode 41 is not formed, the alignment accuracy is 2 to 3 μm.
This is because the above-mentioned amount of 1 μm or more is required.

The image reading device connects the EL light emitting element 4 onto the light receiving element 2 with a transparent and insulating adhesive layer 3 with the EL substrate 11 facing outward, and connects the light receiving element 2 and the EL light emitting element 4 electrically. It is insulated.

Next, a method of manufacturing this image reading device will be explained.

This image reading device includes a light receiving element 2 portion and an EL light emitting element 4.
The parts are made separately and then joined together.

First, the method for manufacturing the light-receiving element 2 is to deposit a chromium (Cr) film on the entire surface of a substrate 1 made of glass, ceramic, or the like, and then apply a resist on the film. A resist pattern is formed by exposing and developing the resist using a mask pattern, and after etching, the resist pattern is removed to form individual electrodes 21 that will become lower electrodes. and,
Amorphous silicon (a-3t) by p-cvd method
A strip-shaped photoelectric conversion layer 22 covering the tip portions of the individual electrodes 21 is formed by photolithography, plasma etching using CF, etc., or patterning vapor deposition using a metal mask. Next, a film of indium tin oxide (ITO) is deposited by a sputtering method, and the tips of the individual electrodes 21 are covered by wet etching using a mixed acid by a photolithography method. A transparent electrode 23 of element 2 is formed.

Next, a method for manufacturing the EL light emitting element 4 will be explained.

EL substrate 1 of about 50 to 100 μm made of glass etc.
A film of ITO or the like is deposited as a transparent electrode 41 on 1 by vacuum evaporation or sputtering to a thickness of about 1400 A, and patterning is performed by photolithography to form a pattern of the transparent electrode 41 as shown in FIG. 3. . As a result, patterns of non-light-emitting portions 46a and 46b are also formed. .

Next, SiH N4 is formed as an insulating layer 42 on the transparent electrode 41.
, S l 02 , Y20s, etc. to a thickness of about 3000A, and ZnS:Mn, etc. to a thickness of about 4000 to 5000A to a thickness of about 4000 to 5000A on the insulating layer 42 by sputtering, electron beam method, etc. A light-emitting layer 43 is formed, and an insulating layer 42 similar to the above is again formed on the light-emitting layer 43 to a thickness of about 3000 A. A metal such as aluminum is evaporated to a thickness of about 1 μm on the insulating layer 42, and then photolithography is performed. An opaque electrode 44 having a light transmitting window 45 is formed by patterning using a method, and an EL light emitting element 4 is manufactured.

The light-receiving element 2 and the EL light-emitting element 4 produced as described above are bonded together via an insulating transparent adhesive layer 3.

In this case, a light transmitting window 45 is placed directly above the light receiving portion of the light receiving element 2.
be placed.

Next, a method for driving an image reading device according to an embodiment of the present invention will be described.
When a bipolar pulse of about 100% is applied, EL light is emitted from the light emitting layer 43 sandwiched between the transparent electrode 41 and the opaque electrode 44. Therefore, no light is emitted from the non-light-emitting portion 46a of the light-transmitting window 45 where the transparent electrode 41 is not formed and the non-light-emitting portion 46b in the peripheral portion of the light-transmitting window 45. EL light emitting element 2
The emitted light emitted upward from the light emitting layer 43 illuminates the document 100 on the EL substrate 11 , and the reflected light passes through the light transmission window 45 and enters the light receiving portion of the light receiving element 2 . Then, the light receiving element 2 generates a charge in response to the light, and outputs image information as a signal under the control of the driving IC.

According to this embodiment, the transparent electrode 41 is provided at the peripheral portion of the light transmission window 45 of the EL light emitting element 4 with a width of about 3 to 4 μm.
Since the non-light-emitting portion 46b is provided so as not to form a
Directly incident light such as light emitted from the light emitting layer 43 passing directly through the light transmitting window 45 and entering each light receiving portion of the light receiving element 2 can be blocked, thereby preventing an increase in the dark output of the image reading device. This has the effect of widening the dynamic range and allowing the image reading device to achieve high gradations.

In this embodiment, the light receiving element 2 and the EL light emitting element 4 are bonded together via an insulating transparent adhesive layer 3.
The adhesive layer 3 is a light-transmitting layer of a medium with a smaller refractive index than the L substrate 11.
It is also possible to form a Specifically, the light-transmitting layer of the medium having a refractive index smaller than that of the EL substrate 11 is, for example, a silicon-based resin (J made by Toray Silicon Co., Ltd.) having a refractive index of about 1.4.
CR6125) may be used as a light-transmitting layer, or an optical thin film such as M g F 2 (n of 1.38) with a small refractive index may be deposited as a light-transmitting layer. By providing an air layer (n of 1.00) only directly above 2, a light-transmitting layer with a small refractive index may be formed.

By providing a light-transmitting layer with a small refractive index as described above, E
Since it is possible to prevent the total reflected light within the L substrate 11 from entering the light receiving element 2 side, the dark output can be reduced by 86% compared to a conventional image reading device. However, about 14% of the dark output remains compared to conventional image reading devices. Of this 14% dark output, 7% is the E of the EL light.
This is because the light reflected from the surface of the L substrate 11 enters the light receiving element 2, and 7% is because the direct emitted light (directly incident light) enters the light receiving element 2 from the periphery of the light transmission window 45.

Therefore, by using the configuration of this embodiment, it is possible to suppress the dark output by 7% due to directly incident light.

In addition, by providing an anti-reflection coating made of glass or a thin film with a refractive index intermediate between the refractive index of the EL substrate 11 and the refractive index of the air in which the document exists, 7% of the surface reflected light is This makes it possible to suppress the dark output.

In addition, as another example, as shown in the cross-sectional explanatory view of FIG. 5 and the plan explanatory view of FIG. By not forming the non-light emitting part 46c,
The light emitted from the light emitting layer 43 is transmitted to the document 10 above the light transmitting window 45.
Since most of the reflected light will be incident on the light receiving portion of the light receiving element 2 directly below the original 100, it is possible to reduce the proportion of reflected light that is incident on the light receiving portion of the adjacent light receiving element 2. This enables accurate reading on the light receiving element 2, and improves the resolution (M) of the image reading device.
This has the effect of improving TF).

(Effects of the Invention) According to the present invention, since the peripheral part of the light transmitting window of the EL light emitting element is made into a non-light emitting part, the direct incident light passing through the direct light transmitting window and entering each light receiving part of the light receiving element is prevented. This has the effect of blocking light and preventing an increase in the dark output of the image reading device.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional explanatory diagram of an image reading device according to an embodiment of the present invention, FIG. 2 is an enlarged cross-sectional explanatory diagram of an EL light emitting element, FIG. The figure is an explanatory diagram of the trajectory of EL light emitting light, FIG. 5 is a cross-sectional explanatory diagram of an image reading device of another embodiment, FIG. 6 is a plan explanatory diagram of the EL light emitting element of FIG. 5, and FIG. 7 is an explanatory diagram of a conventional image. FIG. 2 is a cross-sectional explanatory diagram of the reading device. 3...Light-emitting layer 4...Opaque electrode 5...Light-transmitting window 6...Non-light-emitting portion 00...Original 1... ... Substrate 11 ... EL board 2 ... ... Light receiving element 21 ... Individual electrode 22 ... Photoelectric conversion layer 23 ...・Transparent electrode 3...Adhesive layer 4...EL light emitting element 41...Transparent electrode 42...Insulating layer□Main scanning JJ Direction factor 2nd factor 4th figure 5th main scanning direction

Claims (1)

Claims: An EL light emitting element having a light receiving element formed on a first substrate, and a transparent electrode, a light emitting layer, and an opaque electrode formed on a second substrate. In the image reading device, the light emitted from the EL light-emitting element is reflected by the document surface disposed on the opposite surface of the second substrate on the side opposite to the light-receiving element, and the light emitted from the EL light-emitting element is reflected to the light-receiving element. providing the opaque electrode with a light-transmitting window that guides the reflected light;
An image reading device characterized in that a non-light-emitting portion is provided in which the EL light-emitting element portion in a peripheral portion of the light-transmitting window does not emit light.