JPS59133772A - High-speed picture reading device - Google Patents

Abstract

PURPOSE:To increase the picture reading speed driving simultaneously and in parallel the liquid crystal cells corresponding to plural photoelectric transducers provided on a single long-size photodetecting surface. CONSTITUTION:For a photoelectric transducer 8, the independent photoelectric transducers 10 are bonded close to each other on an insulated substrate 9 with a back electrode used as a conductor. The organic photoconductive matters are attached the transducers 10. Then the lead wires 11, 11... are led out from each back electrode. An optical shutter 12 using liquid crystal is put between the element 8 and an image forming optical system. The shutter 12 contains many liquid crystal segments 13 having a minute width respectively which are distributed close to each other along the image forming line of the image forming optical system. Then independent driving circuits 14 are provided every width corresponding to the width of each group 10 of the transducer 8. Then the segments 13, 13... are driven from an end to the other side simultaneously, in parallel and in series.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an image reading device used in high-speed facsimile and the like, and more particularly to a device that optically scans a document and converts it into an image signal using a photoelectric conversion element at high speed.

For example, as shown in FIG. 1, the most commonly used image reading device using photoelectric conversion uses a condensing mirror 2 to convey an original 1 at a constant speed (this conveyance is called sub-scanning). The collected light from the exposure lamp 3 is irradiated onto the image surface of the original 1, and the reflected light is passed through a collective optical system 4 such as an Optical-7 eyebar array or SELFOC lens (trade name).
At the same time, each element arranged in a straight line in the photoelectric conversion element array 5 is scanned and driven in time series (this is called main scanning) to form an image of the original. The brightness and darkness on the main scanning line was extracted as a serial signal.

However, even if an attempt is made to increase the resolution by increasing the density of the photoelectric conversion element array 5, the image reading device as described above has low sensitivity because it is difficult to increase the voltage applied to each element. There have been problems such as switching noise when scanning and driving the elements is mixed into the image signal, resulting in a decrease in the S/N ratio of the reproduced image.

In order to solve this problem, the inventor of the present application has already arranged a photoelectric conversion element 6 having a long single light-receiving surface on the imaging line instead of the photoelectric conversion element array as shown in FIG. An image reading device has been proposed that includes an optical shutter 7 that has a large number of fine liquid crystal arrays arranged between the imaging optical system 4 and sequentially opens and closes them from one end to the other.

However, the response speed of the optical shutter driven by the liquid crystal array is low, and for example, when the main scanning direction is set to the width of A4 size (21'Omm) and the array density is 10 lines/ms, it is difficult to scan one line in the main scanning direction. The time is approximately 0.
This method has a drawback in that it requires molding for about 1 second and cannot be applied to very high-speed image reading.

The present invention has been made in order to eliminate the defects of the conventional image reading device described above, and is to divide the photoelectric conversion element having the long single light-receiving surface into a plurality of photoelectric conversion elements and connect them. The optical shutter disposed between the imaging optical system is also divided into a number corresponding to the number of divided photoelectric conversion elements, so that a large number of liquid crystal cells constituting the optical shutter of husband 4 can be sequentially driven simultaneously in parallel. The purpose of the present invention is to provide a high-speed image reading device with high speed.

Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

FIGS. 3 and 4 are perspective views showing one embodiment of a photoelectric conversion element and a liquid crystal optical shack used in a high-speed image reading device according to the present invention, respectively.

The photoelectric conversion element 8 shown in FIG. 3 is mounted on an insulating substrate 9 with a conductive material such as an aluminum plate on the back! An inorganic photoconductor such as nickel, aluminum sulfide or amorphous silicon or an organic photoconductor such as polyvinyl carbazole is applied to the pole and thereon.
'J-attached electrically independent photoelectric conversion elements 10 and 1, respectively.
0. . . are attached in close contact with each other. Conductive wires ii, ii, . . . are drawn from the respective back electrodes.

When actually quantifying such a photoelectric conversion element 8, a back electrode and a conductive wire are simultaneously printed on the substrate 9, and then the above-mentioned photoconductive material is vaporized or coated all over the back electrode. Therefore, it is possible to form a photoelectric conversion element group having a single light-receiving surface having a desired area without any particular difficulty in manufacturing.

The photoelectric conversion element 8 needs to be an assembly of photoelectric conversion element groups each having at least two mutually adjacent single light-receiving surfaces io, 1o, . . . . The reason for this is to prevent signal mixing due to image light projected onto the boundaries of the photoelectric conversion element groups when main scanning of the original image is performed simultaneously in parallel for each of the photoelectric conversion element groups, as will be explained in detail later. be.

Now, an optical shutter 1 is constructed using a liquid crystal as shown in FIG. 4 between the photoelectric conversion element 8 configured as described above and the imaging optical system.
2 is interposed.

This optical shutter 12 has a large number of liquid crystal segments (13, 13 . ... are closely arranged along the imaging line of the imaging optical system, and are independent for each width corresponding to the width of each element group 10, 10... of the photoelectric conversion element. . . , each group of liquid crystal segments 13.13. . . . are configured to be driven simultaneously in parallel and in time series from one side to the other.

When using the photoelectric conversion element group 8 and the optical shutter group 12 configured as described above, the optical image of the original is formed on the front shutter group 12 as shown in FIG.

Said party shack group 13, 13. ...is due to the switching of each independent drive circuit! ll opens and closes sequentially, so the optical image spots 15, 15 . . . are arrows 16, 16 pointing from one boundary to the other boundary of each group of single light receiving surfaces io, in, .

Move like...

Therefore, it is possible to avoid forming a spot of the optical image carrying ω of the group on one light receiving surface of the nth group and at the same time forming a part of the light image spot of the nth child group on the other light receiving surface. do not have. This is the reason why each group of light-receiving surfaces must be composed of at least two single light-receiving surfaces.

In addition, when scanning the imaging edge of the imaging optical system, that is, the scanning of the document in the main scanning direction, is performed individually by each group of photoelectric conversion elements having the above structure, each photoelectric conversion element has an angle of 10°, 10, . As shown in FIG. 6, it is obvious that the influence of the boundaries between each of the nine element groups becomes significant in terms of the temporal output fluctuations.

Therefore, each photoelectric conversion element 10, 10. It is desirable to configure the output circuit so that the output of . . . is the sum of the outputs of nine adjacent elements.

In order to further alleviate the influence of the boundaries between the photoelectric conversion elements described above, the boundaries are not perpendicular to the main scanning line, but at a predetermined angle, for example, the facing vertices are parallel to the sub-scanning line 179, as shown in FIG. When the original image light spot approaches the boundary, both photoelectric conversion elements to and io sandwich this boundary.

It would also be effective to make the fluctuations in the output of... more gradual.

Since the image reading device according to the present invention is configured as described above, it is significantly effective in increasing the reading speed even when using an optical shutter that uses a liquid crystal or the like that takes a relatively long time to open and close. Furthermore, the resolution, S/N ratio of the reproduced image, etc. can be improved by making slight improvements to the arrangement of the photoelectric conversion elements and the processing of the signals from them. It is possible to create an image reading device that is completely comparable to that of an image reading device that uses a device.

In the examples, only an imaging system using a collective optical system is shown, but the optical system is limited to this.
, it goes without saying that an imaging system using a normal lens may be used.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the configuration of a conventional image reading device using a photoelectric conversion element array, FIG. 2 is a perspective view showing the structure of an image reading device using an optical shack and a single light receiving surface, and FIG. 3 and FIG. 4 are perspective views showing the configurations of a photoelectric conversion element group and an optical shutter group, each of which is a combination of divided single light-receiving surfaces used in an image reading device according to the present invention, and FIG. 5 is a perspective view of the photoelectric conversion element shown in FIG. 4. An explanatory diagram showing the relationship between the group and the movement of the original image light spot, FIG. 6 is a diagram showing temporal changes in the output of each party % conversion element, and FIG. 7 is a perspective view showing another configuration of the photoelectric conversion element group. It is. 1...W, draft, 2, 3 and 4...imaging optical system,
8 and 1T...photoelectric conversion element group, 10...photoelectric conversion element having a single light-receiving surface, 12...e optical shack group, 13...--opening/closing element of optical shutter. Figure 3 Figure 5 Figure 6 Output (V) Figure 7 n! , 7-

Claims (3)

[Claims] (1) A scanning exposure optical system for an original A plurality of photoelectric conversion element groups each having at least two close-contact single light-receiving surfaces are arranged close to each other along the image-forming line, and this and the above-mentioned imaging optical system. In addition, a minute portion of the original image light can be transmitted sequentially in time series along the imaging line, and each width p- in the imaging line direction is equal to that of each photoelectric conversion element group. By closely arranging the corresponding optical shutter groups, the brightness and darkness of the original image is simultaneously transmitted in parallel from each photoelectric conversion element group corresponding to the optical shutter group as a signal synchronized with the opening and closing of each optical shutter group for each shutter group. 1. A high-speed image reading device characterized in that the image reading device is adapted to take out images at a specific time. (2) By tilting and closing the barrier between the photoelectric conversion elements having the single light-receiving surface with respect to the imaging line of the optical system, the image reading signal generated on the boundary line of the photoelectric conversion elements can be improved. The high-speed image reading device according to claim 1, characterized in that the influence of boundaries is alleviated. (3) By using the sum of the outputs of adjacent photoelectric conversion elements having the single light receiving surface as an image signal of a minute portion of the original image projected through the opening/closing element of the optical shutter, 3. A high-speed image reading apparatus according to claim 1, wherein the image reading apparatus is adapted to reduce the influence of boundaries of image reading signals generated in the image reading process.