JPS6236958A - Picture reader - Google Patents

Abstract

PURPOSE:To obtain picture reading in high speed by irradiating an optical sensor by a visual light source for bias light, irradiating an original by another infrared-ray light source and forming the image of a reflected light on the optical sensor through a graded index fiber array. CONSTITUTION:The optical sensor 1 comprising photoconductors such as CdS, CdSe or solid solution CdS-CdSe is formed in a main scanning direction in the density of, e.g., 8 elements/mm by 1728 elements on an A4 size. The optical sensor 1 is irradiated uniformly from a linear visual source 4 such as a LED array by using a light having a wavelength suitable for the spectral sensitivity of the optical sensor 1 as a steady-state bias light. On the other hand, an original face 6 is irradiated from a linear infrared-ray light source 5 by using a light having a waveform of nearly 1-3mum. The reflected light 3 from the original 6 is made incident into the graded index optical fiber array 2 to form the image of the original on the light sensor 1. This invention utilizes that the optical current of the photoconductive optical sensor is reduced by the irradiation of infrared-ray at a proper wavelength range and a picture is read in the higher speed of 1/20-1/20 or a conventional 5msec/line.

Description

DETAILED DESCRIPTION OF THE INVENTION 2"-/゛Field of Industrial Application The present invention relates to an image reading device that is capable of high-speed reading and has the same dimensions as the width of a document used in various office automation equipment such as facsimiles. be.

Conventional technology Conventionally, in this type of image reading device, a sensor using a Cd5-CdSe solid solution with a large photocurrent and a simple circuit configuration has been put into practical use, but the light response speed of this sensor is slow, so A4 1 in version (8 elements/listening, 1728 elements)
There was a drawback that the reading speed was slow at about 0 m see / 71 ine. Therefore, for example,
-181751, an improvement was made to enable high-speed reading by adding bias light.

In other words, in order to improve the optical response speed of the optical sensor, when the original is irradiated with a linear light source and the reflected light is imaged onto the optical sensor using a focusing fiber array to read the information on the original, a separate linear light source is used to improve the optical response speed of the optical sensor. By directly irradiating the light from the light source as bias light onto the optical sensor and superimposing it on the light reflected from the document mentioned above, the response speed of the optical sensor is increased and high-speed image reading is possible. The structure is such that

In other words, when a photoconductive thin film such as CdS, CdSe, or solid solution Cd5-CdSe is used as an optical sensor, the response speed is about 5 m ICC, and the response speed can be increased to about 4 m4 by adding bias light to this sensor. It is.

Problems to be Solved by the Invention However, in such a conventional method, the optical response speed is about 1 m5eC even when bias light is irradiated, and there is no way to increase it faster than this other than by making the light source brighter. The problem was that there was no.

In addition, as a bias light source, for example, an expensive yellow-green LED can be used.
There were also problems in terms of cost, as two arrays were used.

An object of the present invention is to provide an image reading device that uses an inexpensive light source and can easily perform high-speed reading.

Means for Solving the Problems In the present invention, an optical sensor is constantly and uniformly irradiated with a visible light source for bias light, and a document is irradiated with another infrared light source, and the reflected light from the document is is imaged onto an optical sensor using a focusing fiber array.

Function The present invention utilizes the phenomenon that the photocurrent of a photoconductive optical sensor is reduced by irradiation with infrared light in an appropriate wavelength range, and with the above configuration, image signals can be detected at high speed. I can do it.

The embodiment diagram is a sectional view in the sub-scanning direction showing an embodiment of the image reading device of the present invention. CdS, CdSe and solid solution Cd5-C
An optical sensor 1 made of a photoconductor such as dSe is formed with 1728 elements on an A4 sheet at a density of 8 elements/pan in the main scanning direction, and this optical sensor 1 is converted into an optical sensor using a linear visible light source 4 such as an LED array. It is uniformly and constantly irradiated as bias light using light of a wavelength suitable for the spectral sensitivity of 1. on the other hand,
A linear infrared light source 5 irradiates the document surface 6 with light having a wavelength of about 1 to 3 μm. The structure is such that the reflected light 3 from the original 6 is incident on the light-converging five-page fiber array 2, and an image of the original is formed on the optical sensor 1.

Here, the light intensity of the bias light 8 is CdS.

In the case of an optical sensor mainly composed of CdSe or solid solution Cd5-CdSe, the light intensity on one side of the optical sensor is about 30 to 3 o lux. The photocurrent required by the reading circuit can be obtained1
00 lux or less requires less irradiation infrared light. The amount of infrared light with a wavelength of about 1 to 3 pm from the linear infrared light source 5 is such that the reduction in photocurrent obtained by imaging the reflected light 3 from the white background of the document 6 on the optical sensor 1 increases the steady photocurrent by 100 pm. As, it is 50-100. This reading device can read the white and black signals of a document at high speed. Conventionally, 6
The speed of about m sec / line is 1/1o
It becomes possible to read at a high speed of ~1/2Q.

Here, as a linear visible light source, an LED with low luminous efficiency, E
A solid light source such as L is sufficient, and a linear infrared light source is 1
A W lamp with a high luminous efficiency of about ~3/l1m may be sufficient, and both are inexpensive.

Effect 6 of the Invention -> As described above, the present invention provides an image reading device configured by using both a linear visible light source and an infrared light source, and is capable of capturing images at low cost and at high speed. It has an extremely useful effect industrially in that it can be read.

BRIEF DESCRIPTION OF THE DRAWINGS The figure is a sectional view of an image reading device according to an embodiment of the present invention. 1... Optical sensor, 2... Light focusing fiber array, 3... Reflected light, 4... Visible light source for mark/bias light, 5... Linear Infrared light source, 6...
- Original, 8... group bias light, 9... bias light source.

Claims (3)

[Claims] (1) An optical sensor array formed on a substrate, a linear visible light source for bias light that uniformly and constantly irradiates the optical sensor array, a linear infrared light source that irradiates the original, and an infrared light reflected from the original. An image reading device comprising a focusing fiber array that focuses light onto a photosensor array. (2) The image reading device according to claim 1, wherein the optical sensor array is composed of optical sensors mainly made of CdS, CdSe, or solid solution CdS-CdSe. (3) On the optical sensor surface, when the photocurrent due to steady visible light is taken as 100, the reduction in photocurrent due to the maximum intensity of reflected infrared light from the original is 50 or more. The image reading device according to either item 1 or item 2.