JPS62169570A - Shading correction mechanism for close contact sensor system - Google Patents

Abstract

PURPOSE:To secure the unified light quantity and to remove noises produced in a photoelectric transducing mode by printing a pattern which is inversely proportional to the light intensity on a glass plate and then providing this glass plate between an original and a light source and a focusing light transmitter array. CONSTITUTION:A glass plate 7 containing a printed specific pattern is set between a LED array 4 and a focusing light transmitter array 5 and an original 2. An example of the specific pattern on the plate 7 is shown in the figure. The light quantity given from the array 4 irradiates the original 2 with light intensity in a fixed cycle and in proportion to the pattern on the plate 7 when the light of the array 4 is transmitted through the plate 7. Then the light reflected from the original is condensed by the array 5 to irradiate the light receiving part of a close contact sensor 6. Then the white level fluctuation of the output of the sensor 6 is corrected accurately by selecting correctly the light intensity depending on the pattern on the plate 7 and the positional relations of shading characteristics of the sensor 6 and the array 5.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to OCR and FAX, and particularly to lighting suitable for photoelectric conversion.

[Background of the invention]

In the conventional device, as described in Japanese Utility Model Publication No. 58-37069, a light-shielding plate is provided along the elongated direction of the tubular light source, and the shape of the light-shielding plate is changed in comparison with the intensity of the light, thereby controlling the output signal. I was trying to equalize it.

However, this method has limitations in processing and cannot provide sufficient performance when applied to complex shuding corrections that occur due to the way the contact sensor is made.

[Purpose of the invention]

An object of the present invention is to provide a complex shooding correction mechanism that is determined periodically.

[Summary of the invention]

The present invention prints a pattern that is inversely proportional to the intensity of light on a glass plate, and uses the glass plate as a document and a light source.

Uniform illumination is provided by placing it between arrays of convergent light transmitters.

[Embodiments of the invention]

An embodiment of the present invention will be described below. FIG. 3 is a structural diagram of a photoelectric conversion section using a conventional contact sensor. An LED array 4, a focusing light transmitter array 5, and a contact sensor 6 are arranged and attached to the sensor holder 3 as shown in the figure. The light from the LED array 4 is reflected by the original 2, collected by the convergent light transmitter array 5, illuminates the light receiving section of the contact sensor 6, and is photoelectrically converted. However, in this method, the output from the contact sensor 6 has fluctuations in white level even when the original is pure white as shown in FIG. 4, which causes problems during photoelectric conversion. This white level fluctuation is called chuding (the main cause is that the close contact sensor 6 is large. It is divided into several parts and the control IC
Or caused by manufacturing the light receiving part. This is due to the degree of multilayering of the lenses of the convergent light transmitter array 5. ) FIGS. 1 and 2 show an embodiment of the shading correction mechanism of the present invention while allowing the current contact sensor 6 and convergence light transmitter array 5 that cause shading. LED array 4, focusing light transmitter array 5 and original document 2
A printed glass 7 with a specific pattern printed thereon is provided between the two.

An example of a specific pattern on the printed glass 7 is shown in FIG.

When the amount of light from the LED array 4 passes through the printing glass 7, it irradiates the document 2 with light whose intensity varies in a constant period in proportion to the pattern written on the printing glass 7. This reflected light is a convergent light transmitter. The light is focused by the array 5 and illuminates the light receiving part of the contact sensor 6.

If the positional relationship between the intensity of light due to the pattern, the contact sensor 6, and the shedding characteristics of the convergent light transmitter array is selected correctly, the fluctuation in the white level of the output of the contact sensor 6 can be corrected correctly. Furthermore, printing on glass can be sufficiently processed using current technology.

Also, no pattern is left on the printing glass 7 which becomes the optical path from the original 2 to the convergent light transmitting array 5.

According to this embodiment, the complicated shading inherent in the contact sensor 6 and the convergent light transmitting body array 5 can be corrected by the patterned printing glass 7, and the photoelectric conversion accuracy can be improved.

Furthermore, since the printed glass 7 of the present invention has a structure that covers the upper portions of the LED array 4, the convergent light transmitter array 5, and the contact sensor 6, it can also serve as a sealing structure piece for dustproofing.

〔Effect of the invention〕

According to the present invention, it is possible to correctly correct the inherent shading caused by the contact sensor and the convergent optical transmitter array, thereby greatly improving noise removal during photoelectric conversion, thereby improving the photoelectric conversion accuracy of OCR, FAX, etc. can be significantly improved.

Furthermore, since the outer wall of the seal can also be made of printed glass, a small and inexpensive photoelectric conversion mechanism can be provided.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of the configuration of the contact sensor of the present invention, FIG. 2 is an explanatory diagram showing an example of a printed pattern on the printed glass 7, FIG. 3 is a cross-sectional view of a configuration using a conventional contact sensor, and FIG. The figure is a display diagram of an example of an output signal of a conventional contact sensor. 1; Back guide, 2; Document, 3: Sensor holder, 4;
LED array, 6: Contact sensor, 7: Printed glass. Figure 1 Tower Z diagram (α) (b)

Claims (1)

[Claims] 1. In a photoelectric conversion mechanism consisting of a contact sensor, a convergent light transmitter array, and a light source, a glass plate printed with a certain pattern is placed between the original, the light source, and the convergent light transmitter array for condensing light. A shading correction mechanism for a contact sensor system, which is characterized in that the contact sensor is sealed and the amount of light is made uniform.