JP3682817B2 - Linear light source unit of image reading device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a linear light source unit of an image reading apparatus in which light sources are arranged in a line as a reading light source of an apparatus that reads an image on a document surface in a facsimile, a copying machine, an image scanner, a barcode reader, or the like.
[0002]
[Prior art]
2. Description of the Related Art In recent years, image scanner apparatuses widely used in facsimiles, copiers, image scanners, barcode readers, etc., for example, for facsimiles and the like are roughly classified into contact type and reduction optical systems because of their optical system structures. In any case, in order to read a document, a light source such as an LED array, a cold cathode tube and a fluorescent lamp as a light source for illuminating the document surface with a certain brightness, and a light receiving element such as a photodiode for reading reflected light from the document are provided. Built-in integrated IC. FIG. 6 is a perspective view for explaining the principle of the contact image sensor, and FIG. 7 is a perspective view for showing an effective illumination area of the LED array.
[0003]
As shown in FIG. 6, the contact image sensor 1 includes a light receiving element array 4 including a document reading light receiving element 2 in which a plurality of pixels that perform photoelectric conversion are arranged, and a substrate 3 on which the document reading light receiving element 2 is mounted. An LED array 5 that is a linear light source that irradiates a surface-mounted original, a lens array 6 that forms an image of the original on a sensor light receiving unit, a transparent plate (not shown) on which the original 7 is placed, and these members It is comprised from the exterior case to support.
[0004]
The close contact image sensor 1 operates by irradiating the surface of the document 7 with the LED array 5, forming diffused reflected light on the reading line of the surface of the document 7 on the sensor pixel array with the lens array 6, and the reflected light. Each sensor pixel converts the light / dark information of the original 7, that is, the intensity of light, into an electrical signal and sequentially sends it out in the main scanning direction. Then, the relative position between the document 7 and the sensor pixel row is moved in the sub-scanning direction, and data transmission in the main scanning direction is repeated to convert the two-dimensional image information into a time-series electrical signal.
[0005]
In FIG. 7, the effective illumination area of the LED array 5 in which the plurality of light source LEDs 9 are surface-mounted on the substrate 8 is A, and the effective illumination area for each one is A, and a uniform amount of light is obtained by linear illumination. Therefore, an appropriate number of LEDs 9 are arranged in consideration of the directivity of the LEDs.
[0006]
[Problems to be solved by the invention]
However, the linear light source unit of the contact image sensor described above has the following problems. That is, since the effective illumination area A per LED is narrow and does not produce a non-uniform light amount by linear illumination, the number of LEDs is increased in consideration of the directivity of the LEDs. Therefore, there is a problem that the cost is increased.
[0007]
The present invention has been made in view of the above-described conventional problems, and an object thereof is to extend the effective illumination area per light source, thereby reducing the number of light sources, realizing cost reduction, and inexpensive images. A linear light source unit of a reading device is provided.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, a linear light source unit of an image reading apparatus according to the present invention includes a linear light source that irradiates a document surface, a lens that images reflected light from the document surface, and a the reflected light and the document reading light receiving element for converting received light photoelectrically through the lens, the linear light source unit of the image reading apparatus comprising a fiber optic array which is disposed between the linear light source and the document surface, the line The light source is an LED array, and an optical fiber array is disposed on a surface substantially orthogonal to the light emitted from the LED array .
[0010]
The linear light source unit of the image reading apparatus according to the present invention includes a linear light source that irradiates a document surface, a lens that forms an image of reflected light from the document surface, and a reflected light from the document surface that passes through the lens. In a linear light source unit of an image reading apparatus comprising an original reading light receiving element for receiving light and performing photoelectric conversion, and an optical fiber array disposed between the linear light source and the original surface, the optical fiber array includes a plurality of optical fibers. It is arranged in a straight line and is bundled into one.
[0011]
The linear light source unit of the image reading apparatus according to the present invention includes a linear light source that irradiates a document surface, a lens that forms an image of reflected light from the document surface, and a reflected light from the document surface that passes through the lens. In a linear light source unit of an image reading apparatus comprising an original reading light receiving element for receiving and photoelectrically converting and an optical fiber array disposed between the linear light source and the original surface, a plurality of the optical fiber array bundles are arranged. It is arranged on the surface.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
The linear light source unit of the image reading apparatus according to the present invention will be described below with reference to the drawings. 1 to 5 relate to a linear light source unit of an image reading apparatus according to an embodiment of the present invention. FIG. 1 is a perspective view of an essential part showing an application example to a contact image sensor. FIG. 3A and 3B are a cross-sectional view as viewed from the side X direction and a cross-sectional view as viewed from the front Y direction in FIG. 2, and FIG. 4 illustrates an effective illumination area. FIG. 5 is an explanatory diagram for explaining the positional relationship between the optical fiber array and the LED array. In the figure, the same members as those in the prior art are denoted by the same reference numerals.
[0013]
In FIG. 1, a contact image sensor 10 includes an LED array 5 as a linear light source that irradiates the surface of a document 7, a lens array 6 that forms an image of reflected light from the surface of the document 7, and a surface from the surface of the document 7. A document reading light receiving element 2 for receiving reflected light through the lens array 6 and performing photoelectric conversion is positioned between the light receiving element array 4 surface-mounted on the substrate 3, the LED array 5 and the document 7 surface, and the LED array. An optical fiber array 11 is disposed on a surface substantially orthogonal to the light emitted from 5.
[0014]
In FIG. 2, a plurality of LEDs 9 constituting the LED array 5 are surface-mounted on a substrate 8. An optical fiber array 11A in which a plurality of optical fibers are arranged in a straight line and bundled is arranged directly above each of the plurality of LEDs 9. Both ends of the optical fiber array 11A are held by a holder 12 whose inner wall has a function of reflecting light so as to be substantially orthogonal to the light emitted from the LED 9. 3A and 3B show the arrangement of the LEDs 9 and the optical fiber array 11A. As shown in FIG. 3B, the directivity of one LED 9 is expanded and the effective illumination area per LED 9 ( B) described later is expanded.
[0015]
FIG. 4 shows an effective illumination area per LED 9, and the light emitted from the LED 9 is expanded by the optical fiber array 11A, and the effective illumination area A per LED 9 is expanded. The light that has passed through the optical fiber array 11A expands the directivity of the light source, spreads as an effective illumination area B per piece, and is expanded to about four times, for example. Therefore, the number of LEDs 9 can be greatly reduced. The distance L1 between the LED 9 and the optical fiber array 11A is arranged as close as possible.
[0016]
In FIG. 5, an optical fiber array 11B is configured by arranging a plurality of optical fiber arrays 11A in which a plurality of optical fibers are arranged and bundled in a straight line and arranging a plurality of optical fibers on the surface using a translucent member 13 or the like. As the distance between the LED 9 and the optical fiber array 11B increases from L1 in FIG. 4 to L2 in FIG. 5, the area of the optical fiber array 11B increases, so the number of bundles of the optical fiber array 11A increases. Disadvantageous. For this reason, it is desirable that the distance between the LED 9 and the optical fiber array 11B be as narrow as possible in the design, and for example to be arranged so that L = 0.5 mm, as shown by the two-dot chain line in FIG. Needless to say, the number may be small.
[0017]
【The invention's effect】
As described above, according to the present invention, an LED array is used as a linear light source, and an optical fiber array is arranged between the LED array and a document surface on a surface substantially orthogonal to the light emitted from the LED array. Thus, the effective illumination area of the LED array can be expanded, and the number of LED arrays can be greatly reduced.
[0018]
Moreover, the number of optical fiber arrays can be reduced by disposing the optical fiber array close to the LED array.
[0019]
As described above, by passing the light emitted from the light source through the optical fiber array, the directivity of the light source can be expanded, the effective illumination area of each light source can be widened, the number of light sources can be reduced, and the efficiency is improved. It is possible to illuminate the document surface in a line shape with a uniform light amount. It is possible to provide a low-cost linear light source unit of an image reading apparatus.
[Brief description of the drawings]
FIG. 1 is a perspective view of a main part in which a linear light source unit of an image reading apparatus according to an embodiment of the present invention is applied to a contact image sensor.
FIG. 2 is a perspective view of a linear light source unit in which LEDs are surface-mounted on a substrate.
3A and 3B are a cross-sectional view seen from the side X direction and a cross-sectional view seen from the front Y direction in FIG.
FIG. 4 is an explanatory diagram showing an effective illumination area.
FIG. 5 is a cross-sectional view of a main part showing a positional relationship between an optical fiber array and an LED array.
FIG. 6 is a perspective view of a main part for explaining the principle of a contact image sensor.
FIG. 7 is a perspective view showing an effective illumination area of the LED array.
[Explanation of symbols]
4 Light receiving element array 5 LED array 6 Lens array 7 Document 8 Substrate 9 LED
10 Contact type image sensors 11, 11A, 11B Optical fiber array A, B Effective illumination area L Distance between LED and optical fiber array

Claims (3)

A linear light source that irradiates the document surface; a lens that forms an image of reflected light from the document surface; a document reading light receiving element that receives and photoelectrically converts the reflected light from the document surface through the lens; and the line In a linear light source unit of an image reading apparatus comprising an optical fiber array disposed between a linear light source and a document surface, the linear light source is an LED array and is on a surface substantially orthogonal to the light emitted from the LED array. A linear light source unit of an image reading apparatus, comprising an optical fiber array. A linear light source that irradiates the document surface; a lens that forms an image of reflected light from the document surface; a document reading light receiving element that receives and photoelectrically converts the reflected light from the document surface through the lens; and the line In a linear light source unit of an image reading apparatus comprising an optical fiber array disposed between a planar light source and a document surface, the optical fiber array is a plurality of optical fibers arranged in a straight line and bundled into one. The linear light source unit of the image reading apparatus. A linear light source that irradiates the document surface; a lens that forms an image of reflected light from the document surface; a document reading light receiving element that receives and photoelectrically converts the reflected light from the document surface through the lens; and the line In the linear light source unit of the image reading device comprising an optical fiber array disposed between the surface light source and the document surface,
A linear light source unit of an image reading apparatus, wherein a plurality of the optical fiber array bundles are arranged on a surface.

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