JPH03200117A - Driving method for optical image recorder - Google Patents

Abstract

PURPOSE:To obtain the high resolution recording function of electrically controlled two-dimensional images by adding a recording control electric field in synchronization with image input and forming one screen with two times of scanning. CONSTITUTION:An image input means is modulated in in synchronization with the modulation of the recording electric field so that one screen is formed by two times of scanning. More specifically, an erasing signal is inputted (signal of a crest value Ve and period te) to erase the screen before the recording of the two-dimensional images. An AC current is then impressed in a period t11 and the light signal modulated to correspond to the images is inputted to record the images in the period of the polarity opposite from the polarity of the erasing signal. The AC phase of the recording electric field is shifted by 180 deg. at the time of scanning of the same scanning lines in the subsequent period t12. In addition, the light signal is put into the state of off in the period when the polarity is the same as the polarity of the erasing signal. The light signal for remaining image recording is inputted in the period when the polarity reverse from the polarity of the erasing signal is attained. The image memory of the high resolution over the entire surface of the image memory device is executed in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for driving an optical image storage device, and more specifically, a method for driving a storage device that electronically controls storage of an input two-dimensional image. Regarding.

[Prior Art] A conventional optical image storage device having a bistable electro-optic medium and a photoconductive layer is disclosed in Japanese Patent Application Laid-Open No. 59-216128.
has been disclosed. The basic configuration of the element section is shown in Figure 5(a) (
Shown in b). The principle of operation is as shown in FIG. 5(a): a photoconductor 91, a dielectric mirror 8°, and a bistable electro-optic medium (ferroelectric liquid crystal is used here)6. A recording electric field is applied between the electrodes 3 and 10 sandwiching the two electrodes by the recording electric field generator 12 shown in FIG. 5(b), and a two-dimensional image is input in synchronization with the recording electric field. The resistance of the photoconductive layer decreases at the portions irradiated with light, an electric field is effectively applied to the electro-optic medium, the stable state of the electro-optic medium is reversed, and an image is recorded. In conventional optical image storage devices,
The method of applying a DC electric field as the recording electric field mentioned earlier,
Alternatively, a method of applying an alternating electric field was used.

In Figure 3, the recording electric field in the DC drive method is shown.
a) a clock signal output for each running line; b)
The recording electric field is outputted in synchronization with C), and the two-dimensional image light is outputted in synchronization with C) (before the two-dimensional image input for zero image recording (period te) showing the time chart of g).
An electric field for erasing a recorded image is applied, and then a DC electric field (period t1) is applied as a recording electric field when an optical signal for two-dimensional image recording is input.
~tn) is applied. As a result, the optical signal is turned on and off in accordance with the image information, and when the light is turned on, the resistance of the photoconductive layer decreases and a recording electric field is effectively applied to the electro-optic medium, and in response to this electric field, the electro-optic medium transitions from one stable state (the initially erased state) to the other stable state. When the light is turned off, the photoconductor enters a high resistance state, the electric field applied to the electro-optic medium becomes small, and the initially erased state is selected as the recording state. However, the DC XJA dynamic method has problems such as deterioration of the bistable electro-optic medium and low resolution of recorded images.

In Figure 4, a) shows the clock signal output for each scanning line, b) shows the recording electric field in the AC side force method, C) shows the optical signal for two-dimensional image recording, and d) shows these signals. 0 Two-dimensional image for image recording that shows the image recording state when electric field and optical signals are input. Before applying human power (period te), an electric field for erasing the recorded image is applied, and then a two-dimensional image is generated using the image recording light. An alternating current electric field is applied as a recording electric field when a signal is input (period 1 to Ln).

Using this method, deterioration of the electro-optic medium is less likely to occur. Furthermore, since the conductive anisotropy of the dielectric mirror increases with respect to an alternating current electric field, the resolution of the recorded image improves.

[Problem to be Solved by the Invention] However, when applying an alternating current electric field, there is a problem that it is not possible to record a uniform shin image over the entire screen. ), a stripe-like area is created where the image is not recorded.This is because in the area where the recording electric field has the same polarity as the erasing electric field, even if the optical signal for two-dimensional image recording is manually generated, the electric This occurs because the stable state of the optical medium cannot be reversed.

Therefore, the present invention aims to solve the above problem by applying a recording electric field in synchronization with two-dimensional image input, and to perform high-resolution image storage over the entire surface of the image storage device.

Means for N-method E-problem] An electro-optic medium and a photoconductor having bistable properties, a dielectric mirror, and an image input means for inputting a two-dimensional image to the photoconductor, i;
[l! In a method of driving an optical image storage device whose main components include a recording electric field applying means and a recorded image reading means, the image input means is modulated in synchronization with the V tone of the recording electric field, and one screen is formed by scanning twice. It is characterized by

[Operations] FIG. 1 shows a time chart of the recording electric field and write light modulation of the present invention. In Figure 1, the frequency of the recording electric field is set above the frequency at which the conductive anisotropy of the dielectric mirror decreases, and below the frequency at which the electric field is effectively applied to the liquid crystal. Bistability of an electro-optic medium is determined when Vw is set to a value that allows the image recording state to be erased even when no light is irradiated, and Vw is set to a value that is greater than or equal to a value that allows the stable state of the electro-optic medium to be reversed when light is irradiated. The recording electric field is set between values that do not invert the state, and this recording electric field is shown in Figure 5 (F
It is applied between the electrodes of the element section shown in A).

The principle of the driving method of the present invention will be explained using FIG. 2
Before recording a dimensional image, an erase signal is manually applied (a signal with a peak value Ve and a period te), an AC electric field is applied during the 0th period tll to erase the screen, and the period of polarity opposite to the erase signal corresponds to the image. An image is recorded by inputting an optical signal modulated so as to In the following period t12, when scanning the same scanning line, the alternating current phase of the recording electric field is shifted by 180 degrees, and the optical signal is turned off during the period in which the polarity is the same as that of the erasing signal, and the polarity is opposite to that of the erasing signal. During the period, the remaining image recording optical signals are input. The scanning during the period t12 may be performed simultaneously after performing the same scanning as during the period tel over the entire screen. This made it possible to record images across the entire screen even if the frequency of the recording electric field was increased.

Hereinafter, the details of the present invention will be shown by examples.

[Example 1] 5Z(a) is a sectional view of the element part in the optical image storage device used in the present invention - FIG. 5(b) is the overall configuration of the optical image storage device used in the present invention A diagram was shown.

First, the configuration of the element section of the image storage device will be described.
In FIG. 5, the substrate 2. and 11. is 3 cm
A 3 cm glass substrate was used, and ITO was used for the transparent electrodes 3 and 10. For the alignment films 4 and 7, a 5i02 obliquely deposited film (deposited from a direction tilted by 85 degrees from the normal line of the substrate) was used. These do not need to be formed on the RI substrate.

In addition, an alignment film that can be rubbed may be used instead of the obliquely vapor-deposited film. If it is a mirror, it is not limited to what is shown here). The photoconductor 9 is made of amorphous silicon (film thickness 8
μm) was used. The film thickness may be 100OA to 20μm (other materials such as CdS, GaAs, OPC, etc. can be used as the photoconductor), liquid crystal 6. Chisso C
5-1015 was used, but the invention is not limited to this. Spacer 5.
The thickness was set to 1μ to achieve the most efficient light modulation. Next, the optical system will be explained. FIG. 1(b) Laser 15. uses a laser diode.

Polygon mirror 13. Laser beam scanning prism 14. Laser 151 and recording electric field generator 1
2. is controller 16. It operates synchronously. Of course, the device does not have to have the configuration shown here as long as it performs similar operations. In this example, the laser scanning speed is 1.67 m5/scanning line, and the number of scanning lines is 600. Moreover, in this example, one scanning line is configured by scanning twice, so the scanning prism is used to scan one screen in 2 seconds. 14. Rotate.

In synchronization with the laser scanning, the rivet-moving liquid shown in FIG. 2b) is applied between the electrodes. The peak value Ve of the erasing pulse is
The peak value is set to be sufficient to reverse the spontaneous polarization of liquid crystal molecules even when the laser beam is not irradiated. here t 2
It was set to 0V.

The principle of writing will now be explained.

In Fig. 2, the erasing signal must be input during the erasing period h e (167 m5 in this case) before two-dimensional image recording.
, IKHz square wave signal), zero-order period for erasing the screen (
tll, etc., where tll, etc. indicates one scanning line scanning period) and an alternating current recording electric field (here, the peak value ±IOV, 10
A KHz rectangular wave signal) is applied, and an optical signal modulated to correspond to an image is input during a period of opposite polarity to the erasing signal to record an image. When scanning the same scanning line for the second time (t1
2), the AC phase of the recording electric field is shifted by 180 degrees, and the optical signal is turned off during the period when the polarity is the same as that of the erasing signal, and the remaining image recording optical signal C is turned off during the period when the polarity is opposite to the erasing signal. ). This made it possible to record images across the entire screen even if the frequency of the recording electric field was increased. In addition, the write period L11'' in FIG.
The pulse width of the heating pulse of the recording electric field pulse at tn2 may be wider than that shown in the figure.

The resolution of the device in this example is 81ine pai
rloyn, the contrast was 15:1, and the amount of reflected light relative to the incident light was 30%.

[Example 2] In this example, the same scan as period tll was performed over the entire screen (period tll to tnl), and then after period 1.
A method of performing the scanning from 2 to tn2 all at once will be described. FIG. 3 shows a time chart of the recording electric field used in the method of driving the image storage device in this embodiment.The overall configuration of the optical image storage device is the same as in the first embodiment.

In this example, the laser scanning speed is 1.67 m5/scanning line,
The number of scanning lines is 600, and in this embodiment, one screen is composed of two scans, so it takes 1 second! The if plane is scanned, and the scanning is performed during the period tll to tnl in FIG. 3, and the portion left unwritten earlier is written in one second (period t12 to tn2). Therefore, the scanning prism 13. Rotate at twice the speed. A driving waveform shown in FIG. 3b) is applied between the electrodes in synchronization with laser scanning. The peak value Ve of the erasing pulse is set to be a peak value sufficient to reverse the spontaneous polarization of the liquid crystal molecules even when the laser beam is not irradiated. Here, it was set to 20V.

The writing principle is the same as in the first embodiment.

Further, the pulse width of the write pulse of the recording electric field pulse during the damage period t11 to tn2 in FIG. 2 may be wider than that shown in the figure.

The resolution of the device in this example is 101ine pa
ir/field, the contrast was 20:1, and the amount of reflected light relative to the incident light was 30%.

Although the embodiments have been described above, the present invention can be applied not only to the above embodiments but also to a wide range of electronic dry plates, image display systems, image registers, optical calculation devices, etc. as spatial modulation elements.

[Effects of the Invention] As described above, according to the present invention, the height of an electronically controlled two-dimensional image is achieved by applying a recording control electric field in synchronization with image input and forming one screen by scanning twice. I was able to get the resolution recording function. Furthermore, as an image input means, 2
It has the versatility to be used for both dimensional input and scanning input, as well as reflective and transmissive types. In addition, high reliability is achieved because alternating current is applied to the liquid crystal layer.

[Brief explanation of drawings]

It is a time chart figure. a) is a clock signal, b) is a recording electric field signal, and C) is a two-dimensional optical image signal. FIG. 2 is a time chart in the driving method according to the second embodiment of the present invention. a) is a clock signal, b) is a recording electric field signal, and C) is a two-dimensional optical image signal. FIG. 3 is a time chart in the conventional DC drive method. a) is a clock signal, b) is a recording electric field signal, and C) is a two-dimensional optical image signal. FIG. 954 is a time chart diagram in the AC driving method in the conventional example and a diagram showing the image recording state. a) is a clock signal, b) is a recording electric field signal, and C) is a two-dimensional optical image signal. d) shows the image recording state in the element section. FIG. 5(a) is a sectional view of an element portion in an optical image storage device used in the present invention. FIG. 5(b) is an overall configuration diagram of the optical image storage device used in the present invention. FIG. 1 shows 1... in the driving method of Embodiment 1 of the present invention.
Deflection plate Transparent substrate Transparent electrode Alignment film Spacer Liquid crystal alignment film Electrical mirror Photoconductor Transparent Sun/Moon electrode Transparent electrode Recording Electric field generator Polygon mirror Tracing prism Laser controller Driving power supply Drawing 7) (Contents changed) (None) Figures 1 and above Figure 2 Figure 3 Nekumatate (XJ Figure 5 Procedural Dispute City Official Book (Method) % Formula % Case Indication 1999 Patent Application No. 34072
Title of invention No. 3: Driving method for optical image storage device 3゜Relationship with the person making the correction Applicant: No. 4-1, Nishi-Shinjuku 2r, Shinjuku-ku, Tokyo (236) Representative Director of Seiko Epson Corporation Tsuneya Nakamura 5゜Date of amendment order: April 1990 240 6゜Drawings subject to amendment (all drawings) 7゜Contents of amendment 1. As shown in the engraving and attachment of the drawings originally attached to the iJI document (no changes to the contents)

Claims (1)

[Claims] Optical image storage whose main components include a bistable electro-optical medium, a photoconductor, a dielectric mirror, an image input means for inputting a two-dimensional image to the photoconductor, a recording electric field application means, and a recorded image reading means. 1. A method of driving an optical image storage device, characterized in that the device modulates an image input means in synchronization with the modulation of a recording electric field, and forms one screen by scanning twice.