JPH06152858A - Linear image sensor unit - Google Patents

Abstract

PURPOSE:To reduce the effect of ripples of a line light source and to attain highly accurate reading by using a pressure glass plate through which a light propagates straightforward only in a range of an original to be read. CONSTITUTION:When a radiation light 5 is made incident in a point B of a translucent section 3 being a frosted glass plate formed on the surface of a pressure glass plate 1, the light is diffused thereat and made incident on a transparent part 2 and reaches a read point A. A reflected light 6 from the point A passes through the transparent section 2 and goes to an image forming system. Since the radiation light passes through the translucent part before reaching an original face and is diffused and averaged and the luminous quantity distribution is improved in this way, the uniformity of the illuminance of the original face is improved, and since the reflecting light passes through the transparent part, the resolution is not deteriorated. Thus, ripples of a LED line light source are reduced to improve the read accuracy.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a one-dimensional image sensor unit for optically reading document information.

[0002]

2. Description of the Related Art Recently, one-dimensional image sensor units have been used for reading originals for facsimiles, digital copying machines, image scanners and the like.

An example of the above-mentioned conventional one-dimensional image sensor unit will be described below with reference to the drawings.

FIG. 9 shows a basic structure of a pressing glass which contacts an original of a conventional contact image sensor unit. In FIG. 9, 101 is a document and 102 is a pressing glass. A line light source 103 illuminates the original 101 through a pressing glass. 104 is an equal-magnification optical system, 1
Reference numeral 05 is a one-dimensional image sensor, and 106 is a support plate for the one-dimensional image sensor.

The operation of the one-dimensional image sensor configured as described above will be described below.

First, the line light source 103 is pressed by the pressing glass 10.
The original 101 is irradiated through the beam 2. A light amount corresponding to the density of the illuminated original is imaged on the one-dimensional image sensor 105 by the same-magnification optical system 104 (the progress of light is shown by an arrow in FIG. 9). A light amount corresponding to the lightness and darkness of the original is guided to the one-dimensional image sensor 105 to generate an electric signal. In this way, the original information can be faithfully read optically by the one-dimensional image sensor 105.

[0007]

However, in the above configuration, the ripple of the line light source impairs the fidelity. At present, most line light sources are those in which LED chips are arranged in an array. For example, in an A4 size line light source, 30 LED chips are arranged at substantially equal pitches. FIG. 10 shows a light amount distribution of the LED line light source, 110 is a light amount distribution curve, 111 is an effective irradiation length, and 112 is a ripple. There are the same number of ripples 112 as the number of LED chips in the effective irradiation length 111, and this ripple causes deterioration of the uniformity of the illuminance on the original, and as a result, the accuracy of optical reading deteriorates. .

In view of the above problems, the present invention reduces the influence of the ripple of the line light source and enables highly accurate reading.
A three-dimensional image sensor unit is provided.

[0009]

In order to solve the above problems, in the one-dimensional image sensor unit of the present invention, the light travels straight in the range of the original to be read, and the light does not go straight outside the range of the original to be read. It is provided with the pressed glass.

[0010]

According to the present invention, with the above structure, the pressure glass between the line light source and the original can diffuse the light to reduce the ripple of the line light source, and the uniformity of the illuminance of the original is improved, so that highly accurate reading is possible. Becomes

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A one-dimensional image sensor unit according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a pressing glass of a one-dimensional image sensor unit according to an embodiment of the present invention. In FIG. 1, 1 is a pressed glass, 2 is a transparent part of the pressed glass, 3 is a translucent part of the pressed glass, and 4 is an original. Reference numeral 5 is irradiation light from the line light source, and reference numeral 6 is reflection light from the document.

The operation of the pressing glass thus constructed will be described below with reference to FIGS. 1 and 2.

First, FIG. 2 is a plan view of the pressing glass. A is a line for reading an original, and B is a place where the irradiation light from the line light source is incident on the pressing glass.

Irradiation light 5 enters the pressing glass from point B. Since point B is frosted glass and semi-transparent, the light is diffused and then enters the transparent portion to reach reading point A. The reflected light from the point A travels through the transparent portion 2 to the image forming system.

As described above, according to this embodiment, the irradiation light 5 passes through the semitransparent portion 3 before reaching the original surface, is diffused and averaged, and the light amount distribution is improved. improves. Further, the reflected light from the point A advances through the transparent portion 2 of the image forming optical system, so that the resolution does not decrease. That is, the influence of the ripple of the LED line light source can be reduced.

A second embodiment of the present invention will be described below with reference to the drawings. FIG. 3 shows a pressing glass of a one-dimensional image sensor unit showing a second embodiment of the present invention. In FIG. 3, 1 is a pressing glass and 4 is a document. Reference numeral 5 is irradiation light from the line light source, and reference numeral 6 is reflection light from the document. 7 is a film having a light diffusion effect.

The operation of the pressing glass configured as described above will be described below with reference to FIGS. 3 and 4.

First, FIG. 4 is a plan view of the pressing glass, where A is a line for reading a document and B is a place where the irradiation light from the line light source is incident on the pressing glass.

Irradiation light 5 enters the pressing glass from point B. Since the point B has a light diffusion effect, the light reaches the reading point A after being diffused. The reflected light from point A proceeds to the image forming system.

As described above, according to this embodiment, the irradiation light 5 passes through the film having a light diffusion effect before reaching the document surface, is diffused and averaged, and the light quantity distribution is improved, so that the illuminance of the document surface is improved. The uniformity is improved, and the influence of ripples in the LED line light source can be reduced.

In the second embodiment, the film 7 has a light diffusing effect, but the pressing glass surface may have a frosted glass surface to give a light diffusing effect.

The third, fourth, fifth and sixth embodiments of the present invention will be described below with reference to the drawings.

FIG. 5 is a basic configuration diagram of a contact image sensor unit using the pressing glass of the first embodiment. Reference numeral 10 is a document, 11 is a pressing glass, 12 is a line light source, 13 is an equal magnification lens, 14 is a one-dimensional image sensor, and 15 is a support plate for the one-dimensional image sensor.

FIG. 6 is a basic configuration diagram of a reduction type image sensor unit using the pressing glass of the first embodiment. Reference numeral 10 is a document, 11 is a pressing glass, 12 is a line light source, 17 is a reduction lens, and 18 is a one-dimensional image sensor.

FIG. 7 is a basic configuration diagram of a contact image sensor unit using the pressing glass of the second embodiment. Reference numeral 10 is a document, 16 is a pressing glass, 12 is a line light source, 13 is an equal magnification lens, 14 is a one-dimensional image sensor, and 15 is a support plate for the one-dimensional image sensor.

FIG. 8 is a basic configuration diagram of a reduction type image sensor unit using the pressing glass of the second embodiment. Reference numeral 10 is a document, 16 is a pressing glass, 12 is a line light source, 17 is a reduction lens, and 18 is a one-dimensional image sensor.

[0028]

As described above, the present invention comprises a one-dimensional image sensor, a line light source, an image forming optical system, and a pressing glass which comes into contact with an original. In the one-dimensional image sensor unit that guides the reflected light of the image to the one-dimensional image sensor by the image forming optical system and reads the information by converting the original information into an electric signal, the range of the original to be read is the light traveling straight and the range other than the range of the original to be read. By providing a pressure glass that prevents the light from going straight, the pressure glass between the line light source and the original can diffuse the light to reduce the ripple of the line light source and improve the uniformity of the illuminance of the original. Various readings are possible.

[Brief description of drawings]

FIG. 1 is a sectional view of a pressing glass according to a first embodiment of the present invention.

FIG. 2 is a plan view of a pressing glass in the same example.

FIG. 3 is a sectional view of a pressing glass according to a second embodiment of the present invention.

FIG. 4 is a plan view of a pressing glass in the same example.

FIG. 5 is a basic configuration diagram of a contact image sensor unit using the pressing glass according to the first embodiment.

FIG. 6 is a basic configuration diagram of a reduction type image sensor unit using the pressing glass of the first embodiment.

FIG. 7 is a basic configuration diagram of a contact image sensor unit using a pressing glass according to a second embodiment.

FIG. 8 is a basic configuration diagram of a reduction type image sensor unit using a pressing glass according to a second embodiment.

FIG. 9 is a basic configuration diagram of a pressing glass in contact with a document of a conventional contact image sensor unit.

FIG. 10: Light intensity distribution chart of LED line light source

[Explanation of symbols]

 1 Pressed glass 2 Transparent part of pressed glass 3 Semi-transparent part of pressed glass 4 Original 5 Light emitted from line light source 6 Reflected light from original 7 Film with diffusion effect 13 Same-magnification lens 17 Reduction lens 110 Light intensity of LED line light source distribution

Claims (6)

[Claims] 1. A one-dimensional image sensor, a line light source,
Consists of an imaging optical system and a pressing glass in contact with the original. The original is irradiated with a line light source through the pressing glass, and the reflected light from the original is guided to a one-dimensional image sensor by the imaging optical system to convert the original information into an electric signal. In the one-dimensional image sensor unit for reading by means of the above, a one-dimensional image sensor unit is provided with a pressing glass which is transparent in the range of the original to be read and semitransparent except in the range to be read. 2. A one-dimensional image sensor, a line light source,
Consists of an imaging optical system and a pressing glass in contact with the original. The original is irradiated with a line light source through the pressing glass, and the reflected light from the original is guided to a one-dimensional image sensor by the imaging optical system to convert the original information into an electric signal. In the one-dimensional image sensor unit, the range of the original to be read is transparent, and a pressing glass using a substance having a light diffusion effect is provided outside the range to be read. 3. The one-dimensional image sensor is the same as the original length,
The contact image sensor unit according to claim 1, wherein the image forming optical system is a unity magnification type. 4. The one-dimensional image sensor is shorter than the original length,
The reduction type image sensor unit according to claim 1, wherein the imaging optical system is a reduction type. 5. The one-dimensional image sensor is the same as the original length,
The contact type image sensor unit according to claim 2, wherein the image forming optical system is a unity magnification type. 6. The one-dimensional image sensor is shorter than the original length,
The reduction type image sensor unit according to claim 2, wherein the imaging optical system is a reduction type.