JP2009065244A - Image sensor module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image sensor module capable of reading contents of an object to be read with uniform intensity and hue. <P>SOLUTION: The image sensor module A includes a light source unit 2 having an LED chip 22, a light guide 4 having a light incident surface 4a extending in a main scanning direction (x) and opposed right to the light source unit 2 and a light projection surface 4c projecting light incident from the light incident surface 4a as linear light extending in the main scanning direction (x), and one or more sensor IC chips 3 arrayed in the main scanning direction (x) and receiving reflected light from the object to be read, the light source unit 2 having an eaves portion 24 covering a portion of the light guide 4, on the side of the light projection surface 4c, close to the light incident surface 4a. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image sensor module used in, for example, a flat bed scanner.

  FIG. 5 shows an example of a conventional image sensor module (see, for example, Patent Document 1). The image sensor module X shown in the figure includes a substrate 91, a light source device 92, a plurality of sensor IC chips 93, a light guide 94, and a case 95. The substrate 91 is an insulating substrate, and a plurality of sensor IC chips 93 are arranged in the main scanning direction x. The light source device 92 includes an LED chip 92a that emits red light, green light, and blue light, and emits white light by mixing these lights. The light guide 94 has a rod shape extending in the main scanning direction x, and is made of, for example, transparent acrylic. The light guide 94 is formed with a light incident surface 94a, a light reflecting surface 94b, and a light emitting surface 94c. Light emitted from the light source device 92 is incident from the light incident surface 94a. The light traveling in the light guide 94 is reflected by the light reflecting surface 94b toward the light emitting surface 94c. Linear light extending in the main scanning direction x is emitted from the light emitting surface 94c. By irradiating the reading object with the linear light, the reflected light is received by the sensor IC chip 93. Thereby, the content described in the reading object can be taken in as electronic data.

  However, a part of the light traveling from the light source device 92 that travels obliquely upward is directly emitted from the light exit surface 94c after entering the light incident surface 92a. This light has a remarkably high luminance as compared with the light emitted from the light emitting surface 94c after being reflected by the light reflecting surface 94b. In addition, the directly emitted light described above is not sufficiently mixed in color, and is often emitted as red light, green light, and blue light. For these reasons, there has been a problem that the content described in the edge portion of the reading object is read with an excessively bright and distorted hue.

JP-A-9-275469

  The present invention has been conceived under the circumstances described above, and an object of the present invention is to provide an image sensor module capable of reading the content of an object to be read with uniform brightness and hue.

  An image sensor module provided by the present invention extends in the main scanning direction with a light source device having an LED chip, and has a light incident surface facing the light source device and light incident from the light incident surface in the main scanning direction. And a light guide having a light emitting surface that emits to the reading object as linear light extending in the direction, and one or more light receiving elements that are arranged along the main scanning direction and receive reflected light from the reading object. An image sensor module comprising: a sensor; wherein the light source device has a protuberance that covers a portion closer to the light incident surface of the light emitting surface side portion of the light guide. Yes.

  According to such a configuration, it is possible to prevent light from the light source device from directly exiting from the light exit surface after entering the light entrance surface. Therefore, the content of the reading object can be read with uniform brightness and hue.

  In a preferred embodiment of the present invention, the light source device has a case surrounding the LED chip, and the eaves part is constituted by a part of the case. According to such a structure, it can avoid that the manufacturing process of the said light source device becomes unduly complicated.

  In a preferred embodiment of the present invention, in the case, the eaves portion and the portion connected to the eaves portion in the main scanning direction are flush with each other so that the inner surface can fit the light guide. Has been. According to such a configuration, it is possible to prevent light from leaking from the gap between the eaves portion and the light guide body.

  Other features and advantages of the present invention will become more apparent from the detailed description given below with reference to the accompanying drawings.

  Hereinafter, preferred embodiments of the present invention will be specifically described with reference to the drawings.

  1 and 2 show an example of an image sensor module according to the present invention. The image sensor module A of this embodiment includes a substrate 1, a light source device 2, a plurality of sensor IC chips 3, a light guide 4, a lens array 5, and a case 6. As shown in FIG. 2, for example, the image sensor module A reads the description content of the document Dc as image data while being relatively moved in the sub-scanning direction y with respect to the document Dc placed on the document table St. It is configured as.

  The substrate 1 is made of ceramic such as alumina or aluminum nitride, and has a long rectangular shape extending in the main scanning direction x. The substrate 1 is attached to the lower end of the case 6 and is positioned with respect to the case 6. A plurality of sensor IC chips 3 are mounted on the substrate 1.

  The light source device 2 includes a light source substrate 20, a plurality of terminals 21, three LED chips 22, and a case 23. FIG. 3 shows a process of attaching the light guide 4 to the light source device 2, and FIG. 4 is a front view of the light source device 2. The light source substrate 20 has a rectangular shape, and is made of, for example, ceramic. Alternatively, the light source substrate 20 is made of a composite material of a reinforcing member and a polyimide resin, or a glass epoxy resin. The plurality of terminals 21 are for connecting the light source device 2 to the substrate 1. Each terminal 21 has a clip shape at one end. Each terminal 21 is attached to the light source substrate 20 by this clip-shaped portion. The three LED chips 22 emit red light, green light, and blue light, for example, and are mounted on the light source substrate 20.

  The case 23 is made of white resin, for example, and surrounds the three LED chips 22. In the case 23, an eaves portion 24 is formed. The eaves part 24 is formed by the upper part of the case 23 and protrudes in the main scanning direction x. The inner surface 23 a of the portion connected to the eaves portion 24 of the eaves portion 24 and the case 23 has a shape capable of fitting the light guide 4. In the present embodiment, the angle formed by the straight line connecting the LED chip 22 and the tip of the eaves portion 24 and the normal direction of the light emitting surface 4 c is the critical point when light enters the air from the light guide 4. The length of the eaves portion 24 is set so as to be larger than the corner.

  The plurality of sensor IC chips 3 are semiconductor chips each having a rectangular shape in plan view, each having a light receiving portion (not shown), and is an example of a light receiving sensor referred to in the present invention. The plurality of sensor IC chips 3 are mounted on the substrate 1 along the main scanning direction x, and are arranged immediately below the lens array 5 as shown in FIG. The sensor IC chip 3 has a photoelectric conversion function and is configured to output an image signal having an output level corresponding to the amount of received light.

  The light guide 4 is a highly transparent member made of an acrylic resin such as PMMA (polymethyl methacrylate), and has a circular cross section. The light guide 4 has a light incident surface 4a, a light reflecting surface 4b, and a light emitting surface 4c. The light incident surface 4 a is a surface for introducing light from the light source device 2 into the light guide 4, and is constituted by one end surface of the light guide 4 in the main scanning direction x. The light incident surface 4a is mirror-finished to prevent light from the light source device 2 from being scattered. The light reflecting surface 4b is a surface for reflecting the light traveling from the light incident surface 4a along the main scanning direction x toward the light emitting surface 4c. A plurality of grooves each extending in the sub-scanning direction y are formed in the light reflecting surface 4b. The light emitting surface 4c is a surface that emits light toward the document Dc, and extends in the main scanning direction x. From the light emitting surface 4c, linear light extending in the main scanning direction x is emitted. The light guide 4 is attached to the case 6 via a spacer 61. A portion of the light guide 4 where the light incident surface 4 a is formed is fitted into the case 23 of the light source device 2.

  The lens array 5 is for focusing the light reflected by the document Dc on the plurality of sensor IC chips 3 at the same erect magnification. The lens array 5 includes a block-shaped holder extending in the main scanning direction x and a plurality of lenses arranged along the main scanning direction x.

  The case 6 is made of a synthetic resin and has a substantially block shape extending in the main scanning direction x. The case 6 accommodates the substrate 1, the light source device 2, the plurality of sensor IC chips 3, the light guide 4, and the lens array 5.

  Next, the operation of the image sensor module A will be described.

  According to the present embodiment, the light from the LED chip 22 is not directly emitted from the light emitting surface 4c after entering the light incident surface 4a. For this reason, it is possible to prevent the portion near the edge of the document Dc from being irradiated with extremely high-intensity light or light in which red light, green light, and blue light are not sufficiently mixed. Therefore, the contents described in the document Dc can be read with uniform brightness and hue.

  If the eaves portion 24 is formed by a part of the case 23, it is possible to avoid unduly complicated manufacture of the light source device 2. Further, by fitting the light guide 4 to the case 23, it is possible to prevent light from leaking from the gap between the eaves portion 24 and the light guide 4.

  The image sensor module according to the present invention is not limited to the above-described embodiment. The specific configuration of each part of the image sensor module according to the present invention can be varied in design in various ways.

It is principal part sectional drawing which shows an example of the image sensor module which concerns on this invention. It is sectional drawing which follows the II-II line | wire of FIG. It is principal part sectional drawing which shows the light source device and light guide which are used for an example of the image sensor module which concerns on this invention. It is a front view which shows the light source device used for an example of the image sensor module which concerns on this invention. It is principal part sectional drawing which shows an example of the conventional image sensor module.

Explanation of symbols

A Image sensor module Dc Document St Document placing table x Main scanning direction y Sub scanning direction 1 Substrate 2 Light source device 3 Sensor IC chip (light receiving sensor)
4 Light guide 4a Light incident surface 4b Light reflecting surface 4c Light emitting surface 5 Lens array 6 Case 20 Light source substrate 21 Terminal 22 LED chip (light source)
23 case 23a inner surface 24 eaves part

Claims (3)

A light source device having an LED chip;
A light incident surface that extends in the main scanning direction and directly faces the light source device, and a light emitting surface that emits light incident from the light incident surface to the reading object as linear light extending in the main scanning direction. A light guide;
One or more light receiving sensors arranged along the main scanning direction and receiving the reflected light from the reading object;
An image sensor module comprising:
The light source device includes an eaves portion that covers a portion closer to the light incident surface of the light emitting surface side portion of the light guide. The light source device has a case surrounding the LED chip,
The image sensor module according to claim 1, wherein the eaves part is constituted by a part of the case.   The said eaves part and the part connected to this eaves part in the main scanning direction among the said cases are made into the same shape where each inner surface can fit the said light guide. Image sensor module.

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