JPH0210964A - Compact image sensor - Google Patents

Abstract

PURPOSE:To arrange a light source and a photodetector closely and to make the device small in size by providing a flexible printed circuit board, the photodetector arranged on the printed circuit board and a means supporting the printed circuit board in the folding state. CONSTITUTION:A polyimide base or a stainless sheet or the like is used for a sensor board 11 as a printed circuit board and a photodetector 12 made of an amorphous silicon is arranged on the board 11. The board 11 is fitted to a cylindrical curved face of a mount base 10 and the photodetector 12 is arranged near the top of the base 10. Then a light irradiated from a light source 2 is reflected in an original 1 and led to the element 12. The original 1 is scanned in the direction of arrow, the image of the original 1 is read. That is, the board 11 having the element 12 is formed flexible, the board 11 is fitted while being folded and the light source 2 and the image sensor section are formed integrally, then the light source and the photodetector are arranged closely and a small sized contact image sensor is realized.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an image sensor, and more particularly to a small contact type image sensor.

(Background of the Invention) Fully contact type image sensors have been developed as small image sensors for use in copying machines, facsimile machines, and the like. In this dense, attached image sensor, a sensor array having the same length as the document width and the same density as the reading resolution faces the document. The original is read by scanning the original (or the image sensor) using such a one-dimensional image sensor.

Figure 5 shows one of this type of fully contact type image sensors.
FIG. 2 is a configuration diagram showing a schematic configuration of pixels.

In this figure, 1 is a document on which characters and images are written, 2 is a light source that irradiates light onto the document 1, and 3 is a fully contact type sensor that reads the light reflected from the document 1 out of the light from the light source 2. It is. The sensor 3 includes a transparent glass substrate 4, a light shielding film 5 that restricts light from the light source 2, and a light receiving element that receives light from the original. It is assumed that a plurality of light sources and light receiving elements are arranged in a direction perpendicular to the plane of the drawing (in the width direction of the document).

In this configuration, illumination light illuminates the document from behind the sensor 3 through a transparent window, and the reflected light is captured by a light receiving element close to the transparent window and charged and converted.

FIG. 6 is a block diagram showing the structure of a close-contact type sensor using a 1-magnification erect imaging optical system.

In this figure, 1 is a document on which characters 9 and images are written, 2 is a light source that irradiates light onto the document 1, and 8 is a rod lens array in which convergent optical fibers are arranged in an array of 1 to 3 rows. .

In this configuration, the light from the light source is reflected on the document surface and guided to the rod lens array 8. The light passing through this rod lens array 8 forms a royal life-size image on the sensor 3. Then, it is photoelectrically converted in the same way.

When using a COD-vDMO8 type as a light receiving element, a sensor is constructed by arranging a plurality of Si wafer chips on which elements are formed on a ceramic substrate. In addition, the light receiving element is
In the case of dS or amorphous silicon, a glass substrate is used.

FIG. 7 is a circuit diagram showing an example of wiring for driving the light receiving element 6. In FIG. A blocking diode for crosstalk prevention is connected to each light receiving element. By using such matrix wiring, the number of drive ICs is reduced.

(Problem to be solved by the invention) The above-mentioned fully contact type sensor aims to miniaturize the device, but since the sensor board is a hard one, the structure of the light source, lens, sensor board, etc. There are restrictions on placement and it is not possible to make it sufficiently compact. this is,
This is because the positions of the light source and light receiving element cannot be changed.

The present invention has been made in view of the above-mentioned problems, and its purpose is to realize a compact close-contact image sensor in which a light source and a light receiving element can be placed close to each other. .

(Means for Solving the Problems) The present invention for solving the above problems is an image sensor that has a light receiving element and converts an optical image received by the light receiving element into an electrical signal, and includes a bendable wiring board. a plurality of light receiving elements disposed on the wiring board; a board holding means for holding the wiring board in a bent state; and a light source provided adjacent to the wiring board for illuminating the subject. It is characterized by:

(Function) The wiring board on which the light receiving elements are arranged is held in a bent state by the board holding means. Light from the light source is reflected by the original and guided to the light receiving element.

(Example) Examples of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram showing the structure of an embodiment of the present invention, and FIG. 2 is a block diagram showing the state before the sensor board is attached to the mounting base. In these figures, 1 is a document, and 2 is a light source that irradiates the document 1 with light.

This light source is placed adjacent to a mounting base, which will be described later. 10 is a mounting base for mounting a board. This mounting base 10 has a cylindrical curved surface on its upper part. 11
is a bendable sensor substrate. As this sensor substrate 11, a polyimide substrate or a stainless steel sheet can be used. When using a stainless steel sheet, an insulating layer is formed on the stainless steel sheet, and then a light receiving element and the like are mounted. 12 is a light receiving element arranged on the sensor substrate 11. As this light receiving element 12, an amorphous silicon (α-8i) type is used. The element structure is a sandwich type such as a Schottky barrier structure or a pin structure, or a Brenna type. The sensor board 11 is attached to the cylindrical curved surface of the mounting base 10. Further, the light receiving element 12 is arranged near the top of the mounting base 10. 13 is a connector for taking out the output from the light receiving element 12. Although only one pixel is shown in this figure, it is assumed that a plurality of light sources and light receiving elements are arranged in a direction perpendicular to the plane of the figure (in the direction of the width of the document). In FIG. 1, the matrix wiring section on the sensor board, the blocking diode 9, etc. are omitted.

The light emitted from the light source 2 is reflected by the original 2 and guided to the light receiving element 12. Here, by scanning the original 1 in the direction of the arrow, the image of the original can be read.

By adopting such a configuration, the volume of the image sensor can be reduced to 1/2 or less compared to the conventional one.

Note that bending the sensor substrate 11 does not deteriorate the performance of the light receiving element.

FIG. 3 is a block diagram showing the structure of another embodiment of the present invention.

In this figure, the same parts as in Figure 1 are given the same numbers,
Explanation will be omitted. The difference from FIG. 1 is that the lens 14 is used as a mounting base.

In this configuration, the light emitted from the light source 2 and reflected by the light source 2 enters the lens 14. The light incident on the lens 14 is focused on the light receiving element 12.

Therefore, it becomes possible to effectively utilize the reflected light from the document surface, and it also becomes possible to realize miniaturization.

FIG. 4 is a block diagram showing the structure of still another embodiment of the present invention.

In this figure, the same parts as in Figure 1 are given the same numbers,
Explanation will be omitted. The difference from FIG. 1 is that the light source 2 is used as a mounting base, and there is a light shielding ff! between the light source 2 and the sensor board 11. This is because J15 was installed. This light shielding film 15 is provided with a window through which the irradiated light from the light source 2 is transmitted. Note that the top of the light source 2 needs to have the same shape as the top of the mounting base. In addition, sensor board 1
1 is made of polyimide, and the blocking diode and light receiving element are of the Brehner type.

In this configuration, the illumination light from the light source 2 illuminates the original 1 through the transparent window of the irradiation film 15, and the reflected light is captured by the light receiving element 12 close to the transparent window and photoelectrically converted.

In this configuration, since the mounting base of the sensor board 11 and the light source 2 are also used, it is possible to make the sensor board even smaller than the above-mentioned example.

In the above description, polyimide is used as the material for the sensor substrate, but other materials may be used as long as they can withstand the α-8i film formation temperature of about 250 degrees.

(Effects of the Invention) As described in detail above, in the present invention, the sensor board having the light receiving element is made bendable, the sensor board is attached in a bent state, and the light source and the image sensor section are integrated. It was made to form. This makes it possible to realize a compact contact type image sensor.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of one embodiment of the present invention, FIG. 2 is a configuration diagram showing the state before bending the sensor substrate, and FIGS. 3 and 4 are block diagrams showing the configuration of another embodiment of the present invention. FIG. 5 and FIG. 6 are block diagrams showing the configuration of the conventional example, and FIG. 7 is a circuit diagram showing the circuit around the light receiving element. 1... Document 2... Light source 9... Blocking diode 10... Mounting base 11... Sensor board 12
...Light receiving cable 13...Connector 14...
Lens 15... Light shielding film Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 1-→F scan Fig. 6 Fig. 7

Claims (1)

[Claims] An image sensor that has a light receiving element and converts an optical image received by the light receiving element into an electrical signal, comprising: a bendable wiring board; and a plurality of light receiving elements arranged on the wiring board. A compact image sensor comprising an element, a substrate holding means for holding the wiring board in a bent state, and a light source provided adjacent to the wiring board for illuminating a subject.