JPS6123458A - Picture information reader - Google Patents

Abstract

PURPOSE:To attain reading of a minute signal by forming a photoelectric converter on any one of two polarized plates in a device possible of high speed reading. CONSTITUTION:A polarized plate 2 and a polarized plate 3 whose polarized axis is orthogonal to the plate 2 are formed on upper and lower faces of a substrate 1 to form the photoelectric econverter 4 on the upper face of the plate 2. When an optical signal 8 is made incident, since the light is shut by the polarized plates 2, 3 whose polarized axes are orthogonal, no optical signal 8 reaches the photoelectric converter 4. When it is desired to read a signal, an electric field is applied between electrodes 7, 7', an electrooptic effect leads a part of the signal 8 to the photoelectric converter 4 and the optical current is extracted externally. Since the extracting circuit of the opical signal and the switching circuit are separated electrically in such a case, the circuit for extracting optical signal is immune to the effect of switching noise even if switching is attained at a high speed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an image information reading device applied to facsimile machines, copying machines, and the like.

2. Description of the Related Art Structures of Conventional Examples and Their Problems Today, there is a growing demand for image information reading devices that can read minute signals as quickly as possible in the fields of facsimiles, copying machines, and the like.

The signal reading mechanism of current image information reading devices controls the photocurrent generated in the photoelectric conversion section by electrically switching the photocurrent to the detection circuit section or cutting it off. However, since this output signal is generally weak, if it is electrically switched at high speed, the effects of switching noise etc. will be large, making it impossible to increase the switching speed and causing the problem that it takes too much time to read the image information. there were.

OBJECTS OF THE INVENTION An object of the present invention is to provide an image information reading device that can read image signals at high speed.

Structure of the Invention The present invention provides a substrate having an electro-optic effect, and two substrates whose polarization axes are orthogonal to each other and which are formed so as to sandwich the substrate.
It is configured to have a polarizing plate of a plate and a photoelectric conversion device formed on one of the two polarizing plates, thereby making it possible to read image signals at high speed. shall be.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described based on the drawings.
It is a sectional view of an example. A polarizing plate 2 and a polarizing plate 3 whose polarization axis is orthogonal to the polarizing plate 2 are formed on the upper and lower surfaces of a substrate 1 having an electro-optical effect (for example, PLZT), and a photoelectric conversion device 4 is further formed on the upper surface of the polarizing plate 2. Form. Here, the photoelectric conversion device 4 may be any device that converts an optical signal into an electrical signal, such as a photoconductor, a photodiode, or a phototransistor. 5 (l″j: upper electrode, 6 is a transparent electrode, and both are electrodes for extracting signals from the photoelectric conversion device to the outside. 7 and 7′ are electric fields necessary to cause an electro-optic effect on the substrate 2. However, the electrode does not need to have this shape and may have any structure as long as it has this function, for example, the structure shown in Figure 2.However, in this case, 1o, 1σ must be a transparent electrode.When the optical signal 8 is incident, the light is normally blocked by the polarizing plates 2 and 3 whose polarization axes are orthogonal to each other, so the optical signal 8 is transmitted to the photoelectric conversion device. 4
cannot be reached, so no photocurrent flows. However, if you apply an electric field between electrodes 7 and 7' when you want to read a signal, part of the signal 8 will be able to reach the photoelectric conversion device 4 due to the electro-optic effect, and the photocurrent will not be taken out to the outside. can. Until now, this on/off switch has been performed by an external switching circuit connected to the electrodes 5 and 6, and since noise during switching is superimposed on the photocurrent, the optical signal, especially the minute one, is It was difficult to switch and detect optical signals at high speed, but with this method, the optical signal extraction circuit and the switching circuit are completely electrically separated, so
Even when switching is performed at high speed, the optical signal extraction circuit is not affected by switching noise and always operates in a stable state, making it possible to read minute signals.

As described above, the image information reading device of the present invention has the following advantages:
Since the photoelectric conversion device is formed on a substrate having an electro-optic effect, which is sandwiched between two polarizing plates whose polarization axes are orthogonal to each other, light is It is possible to freely control the signal by guiding it to the photoelectric conversion device or blocking it. Therefore, since the switching circuit and the optical signal extraction circuit are separated from each other, it is possible to detect minute signals even when switching is performed at high speed. In particular, if the present invention is applied to a photoelectric conversion device array in which photoelectric conversion devices are arranged in an array, when reading information from individual photoelectric conversion devices while sequentially scanning, the scanning noise will not be affected by switching noise, etc. Since signals can be detected even at high speeds, image information can be read in a short amount of time.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of an image information reading device that is an embodiment of the present invention, and FIG. 2 is a cross-sectional view of an image information reading device that is another embodiment of the present invention. Substrate with electro-optic effect, 2.36 bases. ...Polarizing plate, 4...Photoelectric conversion device, 5
...Self-upper electrode, 6...Transparent electrode, 7, 7
'... Electrode that provides electric field, 8... Optical signal.

Claims (1)

[Claims] A substrate having an electro-optic effect, two polarizing plates formed to sandwich the substrate and having polarization axes perpendicular to each other, and a photoelectric sensor formed on one of the two polarizing plates. An image information reading device characterized by having a conversion device.