JPH0222872A - Optical sensor device - Google Patents

Abstract

PURPOSE:To obtain an optical sensor device which can suppress a noise effectively, which does not require any reinforcement and whose manufacture is easy by a method wherein a base body is formed of a conductive member and an insulator layer covering both main faces of this conductive member. CONSTITUTION:On a substrate 1, an enamel layer 1b is applied to a circumference of an iron sheet 1a. An image sensor chip 10 where a photodetector part 10a and a drive part 10b are installed collectively and Al conductor layers 5A, 5B are installed on the substrate 1; the conductor layers 5A, 5B except one part are covered with a protective layer 11. Then, the chip 10 and the conductor layers 5A, 5B are connected by wires 8 by a wire bonding operation; sealing frames 13 are erected and installed on the protective layer 11 and are fixed by an adhesive 12. A glass sheet 14 is fixed to the sealing frames 13; the chip 10 and the wires 8 are sealed with the sealing frames 13 and the glass sheet 14 and are protected. Thereby, it is possible to prevent a noise from creeping in an output signal and to obtain a high S/N ratio even when the output signal is very small electric current. In addition, a process to paste a substrate on an Al sheet is not required; an optical sensor device can be manufactured simply.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to an optical sensor device, such as a contact type image sensor.

BACKGROUND OF THE INVENTION In recent years, contact image sensors have been developed as image (original) reading devices in facsimile machines, image readers, and the like. This image sensor has the same size as the reading length and is configured to come into close contact with the document and perform photoelectric conversion.

FIG. 12 shows an example of an image reading device.
1 is a document, 52 is an illumination LED (light emitting diode) array, 53 is a SELFOC lens array, and 57 is a document 5
1 guide plate, 40 an image sensor, 41 a sensor array board, 49 an aluminum plate, A a light receiving element section, C
is a driving IC section of the light receiving element. In the image sensor device having such a configuration, the document 51 is connected to the illumination LED array 5.
2, and the image on the surface of the original 51 is focused as reflected light 54 by the SELFOC lens array 53 onto the light receiving element portion A on the sensor array substrate 41 as a real image of the same size.

As the image sensor 40 used here, for example, one having a structure as shown in FIG. 13 (a Schottky barrier structure is shown here) 40 is known. In FIG. 13, 49 is an aluminum plate, 41 is a glass or alumina substrate, 42 is a first conductor layer and an individual electrode, 43 is a semiconductor light-receiving layer mainly composed of amorphous silicon containing hydrogen,
44 is a transparent electrode, 45 is AJ! A conductor layer such as s A u, 46 is a transparent image =! Membrane, 47 is driver IC148
is a metal wire that connects the driver IC and the conductor layer, and is made by wire bonding or the like. Further, section A is a light receiving element section, section 8 is a wiring section, and section 0 is a drive (IC) section.

However, conventional image sensors have the following problems.

(1) The signal current generated in the light receiving element section A is small. For example, the light sensitivity is 10-'A-cm-"・1x-
1, the light receiving element part of 8 pixels/fl (approximately 100μ
1001 to d)! The photocurrent when x light is irradiated is 1
It is nA. Since the signal current is thus small, the signal current is likely to disappear if noise enters each of the above elements.

(2) The aluminum plate 49 in FIG. 13 functions as a ground circuit reinforcing material. However, the aluminum plate 49 and the substrate 4
Complete adhesion with No. 1 cannot necessarily be expected, so the reliability of noise reduction is insufficient, and it takes a lot of work to bond the two together.

(3) In addition to the structure shown in FIG. 13, there is an image sensor having a structure that uses an image sensor chip in which a light receiving element part A, a wiring part and a driving part C are integrated. In the image sensor having this structure, in addition to disposing an aluminum plate under the glass or alumina substrate as described above, as shown in FIG. 14A or 14B, an image sensor on the glass or alumina substrate 41 is A method is adopted in which a thick film conductor 60 of gold or silver is provided in a region corresponding to the sensor chip 10 and noise is released from the thick film conductor 60 to the ground circuit. However, providing a thick film of noble metal such as gold or silver over a wide area causes high costs.

An object of the present invention is to provide an optical sensor device that effectively suppresses noise, does not require reinforcement, and is easy to manufacture.

20 Structure of the Invention The present invention includes a base and a light receiving device provided on the base.
- In the optical sensor device, the base body is constituted by a conductive member and an insulating layer covering at least both main surfaces of the conductive member.

E, Example The present invention will be explained in detail below.

FIG. 1 is a sectional view of an optical sensor device using an image sensor chip.

A noteworthy word in this example is that without using an aluminum plate,
The substrate 1 is made of enameled iron. That is, the substrate 1 has a structure in which an enamel layer 1b is adhered to the peripheral surface of an iron plate 1a.

On the substrate 1, an image sensor chip 10 in which a light receiving element part 10a and a driving part 10b are integrally provided, and aluminum conductor layers 5A and 5B are installed.
is covered with a protective layer 11.11 except for a part. The image sensor chip 10 and the conductor layers 5A and 5B are connected by wire bonding using wires 8 and 8. A sealing frame 13 stands on the protective layer 11.11, and an adhesive 12
．． 12. A glass plate 14 is fixed on the sealing frame 13, and the image sensor chip 10 and the wires 8.8 are sealed and protected by the sealing frame 13 and the glass plate 14. At both ends of the board 1 are LED light sources 16,
Aluminum support parts 15 and 17 for supporting the SELFOC lenses 18 are erected, and a glass plate 19 serving as a document table is fixed across the support parts 15 and 17. The substrate 1, the support part 15.17 and the glass plate 19 are clamped by a clamping member 20.20 shown in phantom.
It may be fixed. In this example, the substrate 1 is part of the housing of the optical sensor device.

The light from the light source 16 illuminates and scans the document on the glass plate 19, and the reflected light passes through the glass plate 14 with the SELFOC lens 1B and forms an image on the light receiving element portion 10a of the image sensor chip 10. Information is output from the drive unit 10b as an electrical signal.

A grounding terminal of the image sensor chip 10 is connected to an iron plate 1a of the substrate 1, as will be described later, and the iron plate 1a is connected to a grounding circuit. Therefore, noise is effectively prevented from entering the output signal, and a high S/N ratio can be obtained even if the output signal is a minute current.

Furthermore, since the substrate 1 shields noise, there is no need to provide an aluminum plate in addition to the substrate 1.

As a result, there is no need for an aluminum plate, and furthermore, there is no need to attach the substrate and the aluminum plate, which simplifies the manufacture of the optical sensor device.

FIG. 2 is a schematic perspective view for explaining the structure of the image sensor chip 10.

Light-receiving elements 21 made of photodiodes or phototransistors are arranged in the light-receiving element part tOa, and shift registers 22 are arranged in the drive part 10b, and both are connected by leads 23, and the conductor layer shown in FIG. 5
A. Connect on the 5th.

Although this wiring is complicated, it is shown in a simplified manner in FIG. The above structure is made by IC technology.

FIG. 3 is a schematic plan view of a substrate and an image sensor chip placed thereon. Each image sensor chip 10
The grounding lead 24 connected to the grounding terminal is connected to the internal iron plate 1a via the through hole 1C or 1d near the end of the board 1. The four corners of the board 1 are provided with through holes 25 for screwing, for example, to the main body of the facsimile.

The grounding lead 24 is connected to the iron plate 1a as shown in FIG. 4A or 4e. In FIG. 4A, a through hole 1C penetrating the substrate 1 is provided, a grounding lead 24 is formed by screen printing, and a printing material is infiltrated into the through hole 1C, and the peripheral surface of this intrusion portion 24a is brought into contact with the iron plate 1a. I try to let them do it. In FIG. 4B, a through hole 1d is provided in the enamel layer 1b on the upper surface of the substrate 1, and when screen printing the grounding lead 24, the printing material is allowed to enter the through hole 1d, and the tip of the intrusion portion 24b is brought into contact with the iron plate 1a. I try to let them do it.

After making it as one piece and installing each element (not shown), dividing line 2
It is convenient for manufacturing to divide along the lines 5, 25, and 25. A small diameter through hole 26 is formed by a laser along the parting line 25.
Drill the holes close to each other (in the case of blind holes, drill from both ends) to make them easier to break.

Thereafter, this is divided along the dividing line 25 to obtain four substrates 1. For example, the length l is about 300 Iu to include the long direction of A3 size, and the width W for 4 sheets is about 60 m.
shall be.

In the substrate 1 divided as described above, the iron plate 1a is exposed on the divided surface. FIG. 7A is a cross-sectional view of the substrates located on both sides before division, and the figure on day 7 is a cross-sectional view of the substrates located on the inside as well. In the board of Figure 7A, one side of the iron plate 1a is exposed, and in the board of Figure 7, the iron plate 1a is exposed.
It is preferable to cover both side surfaces where a is exposed, including the elements formed near the side surfaces (for example, the conductor layer 5A or 5), with an insulating resin (for example, silicone resin) 27.

This example uses an image sensor chip that integrates the light-receiving element part and the driving part, but it is also possible to use a structure in which the light-receiving element part and the driving IC are provided separately and housed in a sealing frame. Also good. Further, the sealing frame may not be provided, and the sealing may be performed with silicone resin, for example.

In addition to enameled iron plates, the following materials can be used for the substrate: Aluminum, copper talad invar and other materials can be used as the conductive member.

As an insulating layer covering this, in addition to enamel, epoxy resin or the like can be used (metal core substrate). Also,
The insulating layer may be formed by subjecting the conductive material to a chemical conversion treatment, such as by anodizing the surface of aluminum to form an alumina layer.

FIG. 8 shows a structure in which a light-receiving element section is formed directly on a substrate, and a driving I.
FIG. 3 is a cross-sectional view showing an example of an optical sensor device in which C is installed.

A common electrode chromium layer 5 is provided on the substrate 1, and the chromium layer 5
A semiconductor light-receiving layer 3 of amorphous silicon (doped with hydrogen) is provided so as to cover a part of the layer, and ITO (
A transparent electrode 4 made of (Indium Tin Oxide) is provided, and an individual electrode 2 made of aluminum is provided so as to cover the rear end side of the transparent electrode 4. The thickness of each of the above layers is exaggerated. The common electrode 5, the semiconductor light-receiving layer 3, and the transparent electrode 4 constitute a light-receiving element section. A driving IC 7 and an aluminum signal electrode 6 are installed in this order on the rear side of the individual electrode 2, and the IC 7 is connected to the vicinity of the rear end of the individual electrode 2 and the signal electrode 6 by wire bonding with wires 8, 8. IC? The wires 8.8 are sealed and protected by resin 9. FIG. 9 is a plan view showing the above-mentioned elements arranged on the substrate 1. Board 1
The structure and other features are the same as those of the optical sensor device shown in FIGS. 1 to 7A and 7B.

It goes without saying that the structure of the base 1 provides the same effects as the optical sensor device shown in FIG.

A light receiving element using an amorphous silicon semiconductor light receiving layer has the following advantages.

(1) It can be formed using thin film technology, making it easy to manufacture large device groups.

(2) Since it has high resistance, it can be formed into a sandwich structure as shown in Figure 8, and the response is fast.

(3) The absorption coefficient is large in the visible light range.

(4) Characteristics can be controlled by doping with impurities.

In FIG. 10, in place of the drive TC7 in FIGS. 8 and 9,
An example of an optical sensor device in which a shift register 28 is manufactured using thin film technology will be shown. The rest is the same as in the optical sensor device shown in FIGS. 8 and 9.

A gate 28a made of a thin layer of aluminum is formed on the substrate 1, covered with an insulating material 28b of silicon nitride (SisNJ), and a semiconductor film 28C of polycrystalline silicon is further formed to cover the insulating material 28b.

These constitute the shift register 28.

The shift register 28 includes a thin film transistor (Lh, in
It is a transistor with a structure called TPT (film transistor).

The rear end of the aluminum individual electrode 2 is attached to a part of the semiconductor film 28c, and the tip of the aluminum signal electrode 29 is attached to another part of the semiconductor film 28c.

In this future sensor device, the shift register (N moving part) can be formed using the same thin film technology used to form the light receiving element part, individual electrodes, and signal electrodes, so manufacturing is easy. However, in the figure, a portion 2B of the shift register is omitted.

FIG. 11A shows an example of a planar optical sensor device using a Cd5-CdSe sensor as a light receiving element.

As the substrate 1, an enameled iron plate is used as in the above example.

Sensors 34 made of layers of CdS-CdSe are lined up on the base 1, and a common electrode 35 is provided at both ends thereof.
, the individual electrodes 32 are connected. Each of the electrodes 35 and 32 is an individual electrode 32 made of a nickel-chromium alloy.
is connected to a film lead 36 provided on a polyimide film 37. In this example, the drive section is provided on another substrate, and these are not shown.

FIG. 118 is an enlarged partial sectional view passing through the sensor 34 and the electrodes 35 and 32, where the common electrode 35 and the individual electrodes 32 are connected so as to cover the respective end edges of the sensor 34.

The Cd5-CdSe film can obtain a high photocurrent due to its photoconductivity, and an optical sensor device using this film as a sensor can be
This is a device that detects the resistance value between opposing electrodes. Sensor 34 may be made of amorphous silin doped with hydrogen.

Planar optical sensor devices require fewer film forming steps and are easy to manufacture. Further, due to the structure of the base body 1, the effects of noise reduction and ease of manufacture can be achieved as in the above-mentioned example.

In addition to the embodiments described above, various modifications can be made based on the technical idea of the present invention. For example, the material of the substrate (conductive member)
may be a material other than those mentioned above, as long as it has conductivity and has satisfactory mechanical strength. The insulating layer may be any other insulating layer as long as it can withstand the manufacturing process, and some surfaces of the conductive member other than both main surfaces can be omitted. In addition to the plate-shaped base, a base with an appropriate shape may be used depending on the structure of the optical sensor device. In addition to amorphous silicon and Cd5-CdSe, single-crystal silicon and 3e-As-Te can also be used as materials for the light-receiving layer, and its structures include Schottky barrier type, planar type, and P-1-N. Good for molds and other sand inch structures. The drive method is also IC
Drive type, matrix type, etc. are possible. The sensor itself can also be made of a type other than a contact type.

(1) Effects of the Invention Since the optical sensor device according to the present invention uses a base structure in which at least both main surfaces of the conductive member are covered with an insulating layer, noise can be effectively shielded. This effectively prevents noise from leaking into the light receiving element and other elements on the substrate, and as a result, an output signal with a high S/N ratio can be obtained regardless of the magnitude of the output signal. Further, unlike conventional optical sensor devices, a base reinforcing member (for example, an aluminum plate) is not required, and therefore the structure is simple and manufacturing is easy.

[Brief explanation of the drawing]

Figures 1 to 11A and Figure 11 show embodiments of the present invention, in which Figure 1 is a sectional view of an optical sensor device, Figure 2 is a schematic perspective view of an image sensor chip, and Figure 3 is a schematic perspective view of an image sensor chip. The figures are a plan view and a plan view of the substrate and the image sensor chip on the substrate, Figure 6 is an enlarged cross-sectional view taken along the line ■-■ in Figure 5, Figures 7A and 7 are cross-sectional views of the substrate, 8 is a cross-sectional view of a photosensor device according to another example, FIG. 9 is an internal plan view of the photosensor device shown in FIG. 8, FIG. 10 is a cross-sectional view of a photosensor device according to still another example, and FIG. 11A is a FIG. 118 is an enlarged partial cross-sectional view of the photosensor device shown in FIG. 11A. 12 to 14A, and 148 show conventional examples, in which FIG. 12 is a schematic diagram of an image reading device, FIG. 13 is a cross-sectional view of a main part of an image sensor, and FIG. The figure is a partial plan view of another image sensor. In addition, in the symbols shown in the drawings, 1...Substrate 1a...Iron plate 1b...Enamel layer 2.32...Individual electrode 3...Semiconductor light-receiving layer (non-semiconductor light-receiving layer) Crystalline silicon: 1 layer) 4...Transparent electrode 5.35...Common electrodes 5A, 5B...Conductor layer 6.29...Signal bridge 7...RC chimbu 8...Wire 10...Image sensor chip 16
...Light source 18 ...-Selfoc lens 21 ...
... Light-receiving element (photodiode or phototransistor) - Shift register, grounding lead, shift register (thin film transistor), light-receiving element (C
dS-CdSe)

Claims (1)

[Claims] 1. In an optical sensor device having a base body and a light-receiving element provided on the base body, the base body is constituted by a conductive member and an insulating layer covering at least both main surfaces of the conductive member. Features of optical sensor device.