JPH05316282A - Contact type image sensor - Google Patents

Abstract

PURPOSE:To reduce the number of parts and man-hours of assembly by forming a groove therein inserting a sensor substrate and a window conducting light on a frame and fixing a sensor substrate onto the frame. CONSTITUTION:A groove 11 therein inserting a sensor substrate 1 is formed to a frame 2 on a printed circuit board 5. After applying adhesive 23 on the bottom of the groove 11 other than a light conducting window 10 which conducts light, the substrate 1 is inserted and fixed. The difference of coefficients of thermal expansion between the substrate 1 and the frame 2 is large, but the adhesive 23 has the high flexibility after hardening, thus preventing the deformation due to the temperature change. Then the substrate 1 and the frame 2 are fixed through the adhesive 23, unnecessitating holding glass and original guides. Thus, the cost can be decreased by reducing the number of parts and man-hours of assembly.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contact type image sensor, and more particularly to the structure of a contact type image sensor used in a facsimile or the like.

[0002]

2. Description of the Related Art In a conventional contact type image sensor, for example, as shown in FIG. 3, an adhesive 3 which is optically transparent includes a sensor substrate 1 having a photoelectric conversion circuit and a holding glass 7 for holding the sensor substrate 1. Is held by. The holding glass 7 is further fixed to the frame 2 for holding mechanical strength with an adhesive agent 13. On the other hand, a document guide 8 for moving a document on the sensor substrate 1 is fixed on the holding glass 7 with an adhesive 13. Printed circuit board 5
LED (LightEmit) for certifying the original
A towing diode (issuing element) 4 and driving circuit components are arranged.

The illumination light X emitted from the LED 4 is provided with a light guide window 10 formed on the frame 2, a holding glass 7, an adhesive 3,
After passing through the sensor substrate 1, the original 9 is illuminated. The illumination light X is reflected on the surface of the original 9 and a part thereof is converted into an electric signal by the photoelectric conversion circuit formed on the sensor substrate 1.

Regarding the contact type image sensor, for example, the magazine “Nikkei Electronics”, November 1, 1987.
6th issue (No. 434), pp. 207 to 221.

[0005]

In this conventional contact image sensor, since the structure is complicated and the holding glass and the document guide are required, the number of parts and the number of assembling steps are increased and the cost of the product is increased. There are problems such as difficulty in downsizing, and there is no groove to insert the sensor substrate when fixing the sensor substrate to the frame through the holding glass. There have been various problems such as a decrease in S / N ratio of signals and deterioration of image information.

[0006]

According to the contact type image sensor of the present invention, a groove for inserting a sensor substrate and an opaque frame in which a window for guiding illumination light is formed are provided on the groove through a flexible adhesive. The structure is such that the sensor substrate and the frame are fixed inside.

[0007]

The present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a contact image sensor according to a first embodiment of the present invention. A groove 11 for inserting the sensor substrate 1 is formed in advance in the frame 2 on the printed circuit board 5, and an adhesive 23 is applied to the bottom surface of the groove 11 excluding the light guide window 10 and then the sensor substrate 1 is inserted and fixed. . The thermal expansion coefficient difference between the sensor substrate 1 and the frame 2 (the borosilicate glass is generally used for the sensor substrate, the thermal expansion coefficient is about 5 × 10 ⁻⁶ / ° C., the aluminum is generally used for the frame, and the thermal expansion coefficient is Since it is about 26 × 10 ⁻⁵ / ° C.), the adhesive 23 has high flexibility after curing (Shore hardness 70).
It is possible to prevent deformation due to temperature change by using an adhesive. A silicone adhesive, for example, is suitable as this adhesive. Alternatively, an epoxy adhesive having a Shore hardness after curing of 70 or less can be used.

FIG. 2 is a sectional view of a contact image sensor according to a second embodiment of the present invention. The transparent resin 6 is arranged in the light guide window, the transparent adhesive 23 is applied to the entire bottom surface of the groove 11 into which the sensor substrate 1 is inserted on the frame 2, and the sensor substrate 1 is fixed to increase the adhesive area. There is. The transparent resin 6 has a lens effect.

[0009]

As described above, according to the present invention, the groove for inserting the sensor substrate and the window for guiding the illumination light are formed on the frame, and the sensor substrate and the frame are fixed with a flexible adhesive. Due to the structure, the holding glass and the document guide are not required, the cost can be reduced by reducing the number of parts and the number of assembling steps, and further, the product can be downsized by removing the holding glass.

Further, by forming a groove on the frame and inserting the sensor substrate, it is possible to prevent back light and prevent the sensor substrate from being displaced, and the S / N in the electric signal from the photoelectric conversion circuit is also reduced. It has the effect of preventing. In addition, it is also possible to improve the lighting rate of the illumination light by making the LED side surface of the transparent resin arranged in the light guide window a curved surface.

[Brief description of drawings]

FIG. 1 is a sectional view showing a first embodiment of the present invention.

FIG. 2 is a sectional view showing a second embodiment of the present invention.

FIG. 3 is a cross-sectional view showing the structure of the prior art.

[Explanation of reference numerals] 1 sensor board 2 frame 3, 13, 23 adhesive 4 LED 5 printed board 6 transparent resin 7 holding glass 8 original guide 9 original 10 light guide window 11 groove 12 groove bottom

Claims (3)

[Claims] 1. A sensor substrate having a photoelectric conversion circuit, an opaque frame in which a groove for inserting the sensor substrate and a window for guiding illumination light are formed, and a flexible bottom surface of the groove excluding the window. A contact type image sensor characterized in that the sensor substrate is fixed to the frame via a flexible adhesive. 2. An optically transparent resin is arranged in a window for guiding the illumination light of the frame, and the flexible adhesive is an optically transparent adhesive, and the sensor substrate is bonded via the adhesive. And the frame is fixed.
The contact type image sensor described in. 3. The contact image sensor according to claim 2, wherein the optically transparent resin has a lens effect.