JP3058770B2 - Image sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image sensor used for a facsimile, an optical character reader and the like.

[0002]

2. Description of the Related Art FIG. 3 shows an example of a conventional image sensor. In this image sensor, a transparent cover (glass cover) 21 for contacting an imaging target with an upper part of a frame 20
The light source substrate 23 on which the light emitting element 22 serving as a light emitting unit is mounted is fixed to the frame 20 at an angle of about 45 degrees with respect to the surface of the glass cover 21. In addition, a spherical plastic lens 24 is arranged on the optical path of the light emitting element 22, and the original W
A rod lens array 25, which is an optical system for condensing reflected light from, is fixed to the frame 20 perpendicular to the surface of the glass cover 21. Further, a sensor substrate 27 on which a light receiving element 26 serving as a light receiving unit is mounted is provided below the frame 20.

The elastic member 2 is provided on the sensor substrate 27.
8 is fixed, and the upper surface of the elastic member 28 is in contact with the lower lower surface of the frame 20. Thereby, the sensor board 27 is pressed against the bottom surface 20 a of the frame 20 and positioned in the transverse direction of the frame 20.
On the other hand, the sensor board 27 with respect to the longitudinal direction of the frame 20
With regard to the positioning of, only the clearance of the dimensional tolerance is provided in the frame 20, and the sensor substrate 27 is in a free state with respect to the frame 20.

[0004] In such an image sensor, the light emitted from the light emitting element 22 irradiates the original W on the glass cover 21 through the plastic lens 24 at an angle of about 45 degrees with respect to the glass cover 21. . Light that is reflected perpendicular to the glass cover 21 by the document W is collected by the rod lens array 25, received by the light receiving element 26 located immediately below, and converted into an electric signal.

[0005]

In the image sensor as described above, the accuracy of the outer dimensions of the sensor substrate 27 in the transverse direction of the frame 20 must be ± 0.1 mm or less.
Normal output of the image sensor cannot be obtained,
In order to process a substrate with this precision, there is no other way but to perform press working in terms of precision. However, in the case of press working, the cut surface of the board becomes rough due to shearing, and dust such as powder of the board material tends to be generated, which often causes the output of the image sensor to be defective. .

Accordingly, it is an object of the present invention to provide an inexpensive image sensor having good output characteristics.

[0007]

The object of the present invention is to provide an image sensor according to the present invention, that is, a conventional image sensor, in which through holes are formed on both sides in the longitudinal direction of a substrate provided with a light receiving portion. Achieved by an image sensor in which at least one is a reference hole for alignment, a pin corresponding to a through hole is provided in a board mounting portion of the frame, and a pin of the frame is inserted into the through hole of the board to position the board in the frame. Is done.

In this image sensor, a combination of a through hole in the substrate and a pin of the frame is employed, and the substrate can be mounted on the frame only by fitting the pin into the through hole.
In addition, since one of the through holes serves as a reference hole for positioning, the board can be positioned in the transverse direction and the longitudinal direction of the frame by inserting a pin into the reference hole.
Therefore, the positioning of the substrate with respect to the frame is simplified, and the structure for performing the positioning is a simple combination of the through hole and the pin, and the cost is reduced.
Further, since one of the through holes is a reference hole for positioning, the optical axis can be accurately aligned by mounting the substrate on the frame, and the output of the image sensor does not become defective.

The through holes are formed on both sides in the longitudinal direction of the substrate. One of the through holes is a reference hole for alignment, so that not only this reference hole but also the reference hole is fitted. It is important for the pin to be finished with high precision in advance in consideration of the tolerance between the two.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an image sensor according to the present invention will be described based on embodiments. FIG. 1 shows a partially broken side view of one embodiment. In this image sensor, a transparent cover (glass cover) 11 is attached to an upper portion of a frame 10. A light emitting element (eg, an LED chip) is provided in the frame 10.
A light source substrate 13 having the array 12 mounted thereon is fixed at an angle of about 45 degrees with respect to the surface of the glass cover 12 and collects reflected light from a document (not shown) on the glass cover 11. Lens array 1 as an optical system for
4 is fixed perpendicular to the surface of the glass cover 11. Immediately below the rod lens array 14, a sensor substrate 16 on which light receiving elements (such as photodiodes) 15 for receiving light from the array 14 are mounted in an array is arranged.

The sensor substrate 16 is pushed upward via a reinforcing plate 18 by a stopper 17 provided on the bottom of the frame 10 and is fixed by being pressed against the lower portion of the frame 10. The stoppers 17 are not provided over the entire length of the image sensor, but are provided on the projections 10 formed on the sides of the frame 10 on both sides in the longitudinal direction of the image sensor.
a, 10b.

In this embodiment, as shown in a schematic plan view of FIG. 2, the sensor substrate 16 is provided with through holes 16a and 16b at both ends in the longitudinal direction, and the through hole 16a is long. It has an elliptical shape (a stupid hole), and the through hole 16b is a reference hole. Also, the light receiving element 15 on the sensor substrate 16
Are accurately die-bonded and wire-bonded to the reference hole 16b.

On the other hand, pins 19a, 19b corresponding to the through holes 16a, 16b of the sensor board 16 are provided at the lower portion of the frame 10.
19b (only the pin 19b is shown in FIG. 1), the pin 19a is inserted into the stupid hole 16a, and the pin 19b
Is a reference pin, which is fitted into the reference hole 16b. Pin 1
9a and 19b can be formed integrally with the frame 10 by, for example, manufacturing the frame 10 by injection molding of resin.

In particular, the reference hole 16b and the reference pin 19
In the case b, the position and size are finished with high accuracy after a tolerance calculation is performed in advance in order to accurately position the sensor substrate 16 with respect to the frame 10. Therefore, the sensor substrate 16 can be accurately mounted on the frame 10 simply by fitting the pins 19a, 19b of the frame 10 into the through holes 16a, 16b of the sensor substrate 16. Therefore, from the light emitting element 12 to the rod lens array 14
The optical axis that reaches the light receiving element 15 through (see the dashed line in FIG. 1)
Is easily matched.

The image pickup operation of this image sensor is the same as in the prior art. Light emitted from the light emitting element 12 is incident on a document on the glass cover 11, and light reflected from the document is collected by the rod lens array 14. The light is received by the light receiving element 15 and converted into an electric signal.

[0016]

As described above, according to the image sensor of the present invention, through holes are formed on both sides of a substrate provided with a light receiving portion, at least one of which is used as a reference hole, and a pin corresponding to the through hole is connected to the frame. And the pins are fitted into the through holes to position the substrate on the frame, so that the following effects are obtained. (1) The board can be accurately positioned with respect to the frame only by fitting the pins of the frame into the through holes of the board, and troublesome optical axis adjustment is not required during assembly. (2) Since the alignment of the optical axis is improved, the output characteristics of the image sensor are constantly stabilized and improved. (3) Since the board is mounted on the frame with a simple combination of the through hole and the pin, the cost is reduced. (4) Since a substrate having a light receiving portion can be a cut-out product using a router, dust such as powder of the substrate material is less likely to be generated, and output abnormality of the image sensor hardly occurs.

[Brief description of the drawings]

FIG. 1 is a partially cutaway side view of an image sensor according to an embodiment of the present invention.

FIG. 2 is a schematic plan view of a sensor substrate incorporated in the image sensor shown in FIG.

FIG. 3 is a sectional view of a main part of an image sensor according to a conventional example.

[Explanation of symbols]

 Reference Signs List 10 frame 11 glass cover (transparent cover) 12 light emitting element 14 rod lens array (optical system) 15 light receiving element 16 sensor substrate 16a, 16b through-hole (dumb hole, reference hole) 19a, 19b pin (pin, reference pin)

Claims (1)

(57) [Claims] 1. A frame is provided with a transparent cover for contacting an object to be imaged, and a light emitting unit for irradiating light to the object to be imaged in the frame and for condensing reflected light from the object to be imaged. An optical system and a substrate provided with a light receiving unit for receiving light from the optical system, wherein a through hole is formed on each of both sides in the longitudinal direction of the substrate provided with the light receiving unit, At least one of the holes is used as a reference hole for positioning, a pin corresponding to the through hole is provided in the board mounting portion of the frame, and the board is positioned on the frame by fitting the pin of the frame into the through hole of the board. An image sensor characterized in that: