JPH0429366A - Close-contact image sensor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a contact type image sensor, and in detail,
Place the optical sensor part provided on the sensor board against the document surface,
The present invention relates to a contact type image sensor that reads image information while an optical sensor unit and the surface of a document are in close contact with each other.

[Conventional technology]

An image sensor includes a sensor array in which a large number of optical sensor elements are arranged, and an illumination light source such as an LED array, and the image information is read by the sensor array by reflecting light from the illumination light source on a document surface. In conventional image sensors, the sensor array and light source are installed side by side, so a certain distance is required between the sensor array and the document surface in order to reflect the light from the light source through the document surface and back to the sensor array. become. Therefore, a lens array is provided between the sensor array and the document surface, and the reflected light from the document surface is focused by the lens array and focused onto the sensor array to obtain image information.

In recent years, with the sensor array in direct contact with the document surface,
A so-called contact image sensor has been proposed in which light is emitted from a light source provided behind the sensor array through a substrate on which the sensor array is mounted, and reflected light from the document surface is sent to the sensor array. In this contact type image sensor, since the sensor array and the document surface are in close contact with each other, image distortion is extremely small and accurate image information can be obtained. Additionally, since there is no lens array, the image sensor has the advantage of being smaller and lower in cost.

FIG. 5 shows the structure of a conventional contact type image sensor. On the support substrate 1, there are provided a sensor substrate 3 having a light sensor section 2, and a connection piece board 4 on which a wiring 4a for connecting the light sensor section 2 and an external circuit is formed. There is also a wiring 3a connected to the optical sensor section 2 on the surface of the sensor board 3.
has been established. Then, a conductive portion 5 is provided by dry cloth-forming Ag paste across the wiring 3a of the sensor board 3 and the wiring 4a of the connection piece board 4, and the wiring 3a and the wiring 4a are electrically connected. The wiring 6a of the flexible board 6 is connected to the wiring 4a of the connection piece board 4 via the solder 7. The wiring 6a of the flexible substrate 6 is connected to external circuits such as a phantom circuit for image information and a power supply circuit. Light is emitted from a light source provided behind the support substrate 1 through the support substrate 1, etc., and the reflected light from the document surface P is taken into the optical sensor section 2 that is in close contact with the document surface P to obtain image information. read.

However, if the optical sensor section 2 comes into direct contact with the continuously running document surface P, there is a risk that the optical sensor section 2 will be scratched or the internal circuitry will be damaged. Therefore, a transparent thin film glass 8 is attached to the surface of the optical sensor section 2 to protect it.

In addition, in the above structure, the connection board 4 is provided separately from the sensor board 3.
is used in the sensor board 3 equipped with the optical sensor section 2.
By separately manufacturing the connection board 4 with only the layout p4a, it is possible to adopt the optimal manufacturing process or manufacturing conditions according to each function and structure, improving overall manufacturing efficiency or reducing costs. This is because it can be achieved.

[Problem to be solved by the invention]

However, in the conventional contact type image sensor as described above, the wiring 3a of the sensor board 3 and the wiring 4a of the connection board 4 are
Because of the presence of the Ag paste conductive portion 5 that connects the sensor substrate 3 and the connection substrate 4, there was a problem in that the thin film glass 8 could not be adhered tightly to the surfaces of the sensor substrate 3 and the connection substrate 4.

That is, since the Ag paste conductive portion 5 is formed by coating, it is relatively thick and rises high from the surfaces of the sensor substrate 3 and the connection substrate 4. Therefore,
If the thin film glass 8 does not adhere tightly to the sensor substrate 3 and the connection board 4 and is forced to adhere, the thin film glass 8 may break and crack, or the Ag paste conductive portion 5 may be damaged and disconnected. As a result, the manufacturing yield was extremely poor.

Further, since the thickness of the Ag paste conductive portion 5 cannot be accurately controlled, variations occur in the distance from the surface of the optical sensor portion 2 to the surface of the thin film glass 80, that is, the document surface P. When the distance from the optical sensor section 2 to the document surface P changes,
Characteristics such as resolution change, and the quality performance of the image sensor becomes unstable.

Therefore, the object of this invention is to solve the problems of the conventional contact type image sensor as described above, to provide a contact type image sensor that can reliably and well protect the optical sensor part, has a good manufacturing yield, and has stable quality performance. The purpose is to provide sensors.

[Means to solve the problem]

A contact type image sensor according to the present invention that solves the above problems is a contact type image sensor in which a transparent protector is provided on the surface of an optical sensor portion of a sensor substrate, and the transparent protector is made of a flexible transparent film. A wiring pattern connecting the optical sensor section and an external circuit is provided on the bonding surface of the flexible transparent film to the sensor substrate.

[Function] If the transparent protector that protects the optical sensor part is a flexible transparent film, even if the surface of the sensor substrate has slight irregularities, the flexible transparent film will flexibly deform and protect the sensor. It can be attached closely to the surface of the board. A flexible transparent film will not break or crack even if it is deformed. If the flexible transparent film is in close contact with the surface of the sensor substrate, the distance from the optical sensor section to the surface of the flexible transparent film, that is, the document surface can be set accurately.

Further, if the flexible transparent film is provided with a wiring pattern that becomes part of a wiring circuit that connects the optical sensor section and an external circuit, there is no need to provide an Ag paste conductive section as in the conventional case. To create a wiring pattern on a flexible transparent film,
Since a thin film wiring pattern can be easily formed using ordinary thin film forming technology or microfabrication technology, it does not have to be as thick as the Ag paste conductive part, and the amount of deformation of the flexible transparent film can be reduced. As a result, the above-described attachment to the sensor substrate can be performed better, and characteristics such as resolution are also more stable.

〔Example〕

FIG. 2 shows a cross-sectional structure of the main parts of the image sensor, and FIG. 1 shows the state in the middle of its manufacture.

A light sensor section 22 is mounted on a support substrate 10 made of glass or the like.
A sensor board 20 provided with a sensor board 20 and a board 3 for connection to an external circuit
It is equipped with 0. A wiring 24 connected to the optical sensor section 22 is formed on the surface of the sensor substrate 20. Wiring 32 connected to an external circuit is formed on the surface of the connection board 30. A wiring 42 provided on a flexible substrate 40 for connection to an external circuit is connected to the wiring 32 of the connection substrate 30 via an anisotropic conductive resin 50.

As the anisotropic conductive resin 50, a conductive resin for circuit connection that is used in the ordinary circuit field, such as a thermosetting resin mixed with a filler such as Ni to impart conductivity, can be used. The connection part by this anisotropic conductive resin 50 is
Since the flexible substrate 40 can be peeled off and reused, if a defective sensor is found by inspecting the assembled image sensor, the flexible substrate 40 can be peeled off from the connection substrate 30 and reused.

A flexible transparent film 60 is pasted on the sensor substrate 20 and the connection substrate 30. The flexible transparent film 60 is preferably made of a material with excellent light transmittance and abrasion resistance, and various films made of PET resin or the like can be used. The flexible transparent film 60 can be attached by adhesion or other conventional joining methods. A wiring pattern 62 is formed on the lower surface of the flexible transparent film 60, that is, on the surface to be bonded to the sensor substrate 20 and the like.

As the means for forming the wiring pattern 62, ordinary wiring circuit manufacturing means using vapor deposition or other thin film forming techniques can be used. As the conductive material constituting the wiring pattern 62, Ni or other ordinary conductive material is used. Flexible transparent film 6
0 on the surfaces of the sensor substrate 20 and the connection substrate 30, the wiring pattern 62 of the flexible transparent film 60 is attached to the wiring 24 of the sensor substrate 20 and the connection substrate 3.
0 wiring 32. The flexible transparent film 60 is flexibly deformed so as to absorb the irregularities caused by the wiring 24.32 and the wiring pattern 62 of each substrate 20.30, and is adhered to the surface of each substrate 20.30.

Although the structure of the image sensor shown does not show the structure of the light source, signal processing section, power supply, etc., the structure of these parts can be the same as that of a normal contact type image sensor, so please refer to the details below. Further explanation will be omitted.

Next, the embodiment shown in FIGS. 3 and 4 is a case where the flexible transparent film 60 is also used as the flexible substrate.

In the embodiment, the connection substrate 30 on which the wiring 32 is formed
However, in this embodiment, an auxiliary substrate 34 made of simple glass or the like is used. A flexible transparent film 60 is attached to the surfaces of the auxiliary substrate 34 and the sensor substrate 20. The flexible transparent film 60 not only covers the surfaces of the sensor substrate 20 and the auxiliary substrate 34 but also covers the auxiliary substrate 3
It extends from 4 to the part that connects to the external circuit. Wiring pattern 6 formed on flexible transparent film 60
4 is connected to the wiring 24 of the sensor board 20, and
It continues to the outside of the auxiliary board 34 and is connected to an external circuit.

That is, in this embodiment, the flexible transparent film 60 not only functions to protect the surface of the optical sensor section 20, etc., but also functions as a flexible substrate that connects the optical sensor section 20 and an external circuit. . in this way,
If the flexible transparent film 60 is also used as a flexible substrate, the number of parts and manufacturing steps can be reduced, which is effective in simplifying the structure of the entire image sensor, improving manufacturing efficiency, and reducing costs.

Further, in the embodiment described above, a hard coat layer 66 is formed on the surface of the flexible transparent film 60 on the document side to improve wear resistance. The material and forming means for the hard coat layer 66 include, for example, coating the surface of the transparent film 60 made of PET resin with the hard coat layer 66 made of silicone resin of about 100 nm, or coating the hard coat layer 66 made of silicone resin with a thickness of about 100 nm, or coating the surface of the transparent film 60 made of PET resin with a hard coat layer 66 made of silicone resin, or coating the hard coat layer 66 made of silicone resin with a thickness of about 100 nm. A conventional hard coat layer for surface protection is applied, such as coating with a resin or forming a thin film of a glass material of SiOx component by means of CVD or the like.

〔Effect of the invention〕

According to the contact type image sensor according to the present invention described above, a flexible transparent film is used as a transparent protector for protecting the optical sensor section in place of the conventional thin film glass, so that wiring, etc. It can be flexibly deformed and tightly adhered to sensor substrates and connection substrates that have irregularities due to roughness, and unlike thin film glass, it does not break or crack during installation. As a result, the problem of reduced product yield can be solved. In addition, even if an impact or pressure is applied to the surface while using the image sensor,
A flexible transparent film can flexibly deform and release stress, which prevents accidents such as cracks from occurring.

Flexible transparent film is easier to manufacture than thin-film glass, and it is easier to handle because there is no fear of breaking like thin-film glass, which simplifies assembly of image sensors and can be provided at a lower cost. become.

In addition, the flexible transparent film has a wiring pattern that becomes part of the wiring circuit that connects the optical sensor section and the external circuit, so simply attaching the flexible transparent film to the sensor board, etc. A part of the wiring circuit to the sensor section is formed. Forming a wiring pattern on a flexible transparent film can be done efficiently and with high precision using ordinary circuit forming means, so it is easier to conduct the conduction between the sensor board and the connection board than with the conventional coating of Ag paste. This allows for much finer, more accurate, and thinner conductive parts.
It can be formed more efficiently. If the thickness of this conductive part becomes thinner and more accurate, the distance from the optical sensor placement part to the surface of the flexible transparent film, that is, the document surface, will also be more accurate.
Characteristics such as resolution become stable. Moreover, since the irregularities on the bonding surface of the flexible transparent film are reduced, the flexible transparent film can be stuck more closely to the sensor substrate or the like.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a contact image sensor according to the present invention during manufacturing, and FIG. 2 is a cross-sectional view after manufacturing.
FIG. 3 is a sectional view showing another embodiment during manufacture, FIG. 4 is a sectional view after manufacture, and FIG. 5 is a sectional view of a conventional example. 20... Sensor board 22... Optical sensor section 60.
...Flexible transparent film (transparent protector) 62.64...
・Wiring pattern

Claims (1)

[Claims] 1. In a contact image sensor in which a transparent protector is provided on the surface of the optical sensor part of the sensor substrate, the transparent protector is made of a flexible transparent film, and the surface of the flexible transparent film bonded to the sensor substrate is A contact image sensor characterized by being provided with a wiring pattern that becomes part of a wiring circuit that connects a sensor section and an external circuit.