JPH09258258A - Method and device for recording image - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lower the voltage applied to an optical sensor just after voltage application and to reduce the occurrence of abnormal discharge, a noise and a defect by setting so that the voltage applied between electrodes of the optical sensor and a liquid crystal recording medium becomes higher at a voltage application end time than a voltage application start time. SOLUTION: A separation type information recording medium oppositely arranging the optical sensor 10 and the liquid crystal recording medium 20 through a gap or an integrated type information recording medium laminating the optical sensor and the liquid crystal recording medium is used. Then, when an image is exposed through the optical sensor 10, and the voltage is applied between the optical sensor 10 and the liquid crystal recording medium 20, and the image is recorded, the voltage applied between both electrodes is set so that the voltage becomes higher at the voltage application end time than the voltage application start time. By making such voltage application condition, the voltage applied to the optical sensor 10 just after the voltage application is lowered.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image recording method and apparatus for recording an image on a liquid crystal recording medium having a polymer-liquid crystal composite layer.

[0002]

2. Description of the Related Art Conventionally, an information recording medium having a liquid crystal-polymer composite layer formed on an electrode and an optical sensor having a photoconductive layer formed on the electrode layer are arranged to face each other, and image recording is performed by voltage application exposure. What can be done is disclosed in JP-A-6-130347 and JP-A-5-130347.
No. 165005 is known. Further, an information recording medium in which a liquid crystal-polymer composite is formed on an electrode and an optical sensor in which a photoconductive layer is formed on an electrode layer are opposed to each other and image recording is performed by voltage application exposure is disclosed in JP-A 4-362
No. 916. FIG. 1 is a diagram showing the configuration of an information recording apparatus using such an information recording medium. In the figure, reference numeral 10 denotes an optical sensor, and reference numeral 20 denotes an information recording medium. In the optical sensor 10, a transparent electrode 12 and a photoconductive layer 13 are sequentially laminated on a transparent support 11, and an information recording medium 20 is provided.
A transparent electrode 22 and a liquid crystal-polymer composite layer 23 are sequentially laminated on a transparent support 21, and a skin layer 24 is formed on the liquid crystal layer surface.
Are formed.

A type in which an optical sensor and an information recording medium as shown in FIG. 1 are opposed to each other with a space of about 10 μm using a spacer such as polyethylene or polyimide, and exposed by voltage application, and FIG. A structure in which an optical sensor and an information recording medium are laminated as shown in FIGS. 2A and 2B has also been proposed. In a laminated recording medium, information is recorded on the optical sensor as shown in FIG. 2A. As shown in FIG. 2B, the recording phase is directly laminated and the transparent dielectric intermediate phase 2 is used.
There are some which intervene 5. Such an optical sensor 10
When the information recording medium 20 and the information recording medium 20 are opposed to each other and a voltage is applied between the electrodes 12 and 22 by a power source 30 as shown in FIG. 3 and visible light is irradiated as writing light, the photoconductive layer 13 of the photoconductive layer 13 is irradiated in accordance with the exposure intensity. The conductivity changes, the electric field applied to the liquid crystal layer 23 changes, the alignment state of the liquid crystal changes, and the applied voltage is turned off.
Then, the state is maintained even after the electric field is removed, and the exposure information is recorded.

To reproduce the recorded exposure information, for example, as shown in FIG. 4, reproduction light is emitted from the light source 40 to the information recording medium 20, and the transmitted light is read by the photoelectric conversion device 60 and converted into an electric signal. It is done by As the light source 40, a white light source such as a xenon lamp or a halogen lamp or a laser beam is used, and it is desirable that the reading light with which the liquid crystal recording medium is irradiated be selected to have an appropriate wavelength light and be irradiated. The incident light is modulated according to the alignment state of the liquid crystal of the information recording medium, the transmitted light is converted into a digital signal by the photoelectric conversion device 60 including a photodiode or the like, and the converted signal is output to a printer or a CRT as necessary. Is output.

[0005]

When an image is recorded by the above method, a high electric field is applied to the photoconductive layer of the photosensor immediately after the voltage is applied, which causes abnormal discharge, noise on the image, and defects. There is a problem such as. The present invention has been made in view of the above point, and an object of the present invention is to reduce the voltage applied to the photosensor immediately after the voltage is applied to reduce the occurrence of abnormal discharge, noise, and defects.

[0006]

The present invention provides a separate type information recording medium in which an optical sensor and a liquid crystal recording medium are opposed to each other with a gap interposed therebetween, or an integrated type information recording medium in which an optical sensor and a liquid crystal recording medium are laminated. When an image is exposed through an optical sensor and a voltage is applied between the optical sensor and the electrodes of the liquid crystal recording medium to record an image, the voltage applied between both electrodes is determined when the voltage application is completed rather than when the voltage application is started. Is set so that the voltage applied to the optical sensor immediately after the voltage is applied is reduced by setting such voltage application conditions to reduce the occurrence of abnormal discharge, noise, and defects. be able to.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the image recording of the present invention will be described in detail with reference to the drawings. In the image recording of the present invention, in order to investigate the state of the voltage applied to the liquid crystal medium and the optical sensor, the voltage applied to the optical sensor and the liquid crystal medium was calculated using the measuring device shown in FIG. In FIG. 5, an electrode 14 is formed on the photoconductive layer 13 of the photosensor 10, and
A liquid crystal recording medium is connected in parallel with a resistor and a capacitor, a corresponding resistor 51 and a capacitor 52 are connected as a pseudo liquid crystal medium to the optical sensor 10, and a resistor 5 for measuring current is further connected.
0 was connected and a voltage was applied by the power supply 30 to measure the current value. Further, the light source 40 and the shutter 41 were used for the optical sensor 10 to expose the optical sensor 10 with light of a predetermined intensity for a predetermined time. An example of the measurement result is shown in FIG. Applied voltage is 400V,
The exposure condition was that G light with an intensity of 20 Lux was exposed for 1/30 seconds at the same time when the voltage application was started.

Next, a method for calculating the voltage applied to the pseudo liquid crystal medium and the photosensor from the measurement result will be described. The following equation (1) is established between the current value I _EX measured by the method of FIG. 5 and the voltage and resistance component current applied to the pseudo liquid crystal medium. I _EX = V _LC / R _LC + C _LC · dV _LC / dt (1) Further, the initial condition of the voltage applied to the pseudo liquid crystal medium is V _LC (0) = 0 (2) and (1 Equation (3) is modified to obtain the voltage applied to the pseudo liquid crystal medium by the following equation (3): V _LC (t + Δt) = V _LC (t) + (I _EX −V _LC / R _LC ) Δt / C _LC (3) I calculated.

FIG. 7 shows the result of calculating the voltage applied to the pseudo liquid crystal medium by the above method. The voltage applied to the liquid crystal medium is
In a very short time from the start of voltage application, the capacitance is distributed to the capacitance ratio of the optical sensor and the liquid crystal medium. After that, the voltage of the liquid crystal medium and the light sensor changes due to the current of the resistance component of the light sensor and the liquid crystal medium. In the calculation result example shown in FIG. 7, 0.2
The initial charge is completed in about 0.3 msec, and the voltage of the liquid crystal medium reaches V ₁ .

For the photosensor as well, if the voltage applied to the photosensor is calculated by the same method as the equations (1) to (3), it is difficult to approximate the current value of the photosensor immediately after the voltage is applied by a simple equation. Therefore, the difference between the applied voltage and the voltage applied to the liquid crystal medium was used as the voltage of the optical sensor. In the calculation example shown in FIG. 7, since the internal resistance of the power supply is small,
The initial charge is completed in 0.3 msec, and thereafter, the total voltage applied to the liquid crystal medium and the photosensor becomes equal to the applied voltage. That is, the voltage applied to the photosensor was calculated using the following formula. V _PS = V _AP −V _LC (4) The calculation result is shown in FIG. As can be seen from FIG. 8, a voltage of about 340V is applied to the photosensor immediately after the voltage is applied, and thereafter, the voltage applied to the photosensor decreases with time. It is likely to cause abnormal discharge, noise, defect, etc. It is considered that this is because the photosensor is locally brought into conduction due to the nonuniformity of the medium, and the nonuniformity due to the high electric field is emphasized to cause granular noise on the image.

Next, a method of reducing the voltage applied to the photosensor in order to prevent the occurrence of abnormal discharge and noise will be described. FIG. 9 shows an example of a voltage applying method for reducing the voltage applied to the optical sensor. Using a measuring device similar to that shown in FIG. 5, as shown in FIG.
When a slope voltage is applied to increase V,
FIG. 10 shows the result of similar calculation of the voltages applied to the pseudo liquid crystal medium and the photosensor.

The result of FIG. 10 and the constant voltage 40 shown in FIG.
Comparing the voltage V _PS applied to the optical sensor when 0 V is applied, when a constant voltage is applied, the threshold voltage (200 V) of the liquid crystal medium is 57 msec after the start of voltage application.
To reach. At this time, the voltage V _PS applied to the optical sensor is
It was in the range of 340 to 200 V in the dark part (■ in the figure). On the other hand, when the voltage is applied with the slope voltage, the threshold voltage is reached after about 80 msec, and the voltage V _PS applied to the photosensor is 260 to 180 V in the dark part (■ in the figure).
In the range, the value was considerably lower than that in the case of applying a constant voltage.

FIG. 11 shows the result of calculating the potential difference between light and dark in the measurement results shown in FIGS. 8 and 10. As shown in FIG. 11, when the voltage in the dark portion is the threshold voltage (in FIG. 8, 57 msec after the start of voltage application,
Then, when comparing the potential difference of light and dark after 80 msec from the start of voltage application, it is found that they are almost equal regardless of the voltage application conditions.

Although the method of linearly increasing the applied voltage has been described above, the present invention is not limited to such a method, and the condition is such that the voltage at the end of the applied voltage is higher than the voltage at the initial voltage application. If the method of applying voltage with
There is no particular limitation on the shape of the voltage waveform.

Another method of reducing the voltage of the optical sensor will be described. FIG. 12 shows voltage application conditions for reducing the voltage of the optical sensor. In FIG. 12, condition A is the case of a normal image recording method, and 400 V at the same time as image exposure.
Image recording is performed by applying the voltage of. Condition B is the image recording method of the present invention.
An image is recorded by applying a voltage of 200 V for the period c and subsequently applying a voltage of 400 V, and simultaneously performing image exposure. It should be noted that the voltage application before image exposure affects the photo-induced current during image exposure because it induces a base current, which in turn affects the voltage applied to the photosensor and the liquid crystal medium.

Using the pseudo liquid crystal medium according to the method shown in FIG. 5, the results of calculating the voltages applied to the liquid crystal medium and the photosensor under the conditions A and B of FIG. 12 are shown in FIG.
3, shown in FIG. In addition, both FIG. 13 and FIG.
The exposure start time is displayed as t = 0, and A (photo) in the figure is displayed.
o) and A (dark) are the bright and dark parts in condition A,
B (photo) and B (dark) indicate the voltages of the bright portion and the dark portion under the condition B. From FIG. 13, assuming that the threshold voltage of the liquid crystal medium is 250 V, under the condition A (bright area □, dark area ■), 62 mse from the start of voltage application.
After c, the voltage in the dark portion reaches the threshold voltage. On the other hand, in the case of condition B (bright area ○, dark area ●), 400 V
The voltage in the dark portion reaches the threshold voltage 42 msec after the start of the voltage application. From FIG. 14, the voltage applied to the photosensor is in the range of 350 to 130 V for the condition A and 250 to 130 V for the condition B, and the result that the voltage applied to the photosensor is lower in the condition B. Was obtained.

FIG. 15 shows the results of calculation of the potential difference between the bright portion and the dark portion of the photosensor under the conditions A and B. Comparing the light-dark potential difference when the voltage of the liquid crystal medium is the threshold voltage, it is found that it does not change significantly depending on the voltage application conditions.

Although the method of increasing the voltage only once at the start of exposure is shown here, the number of times of increasing the voltage may be two or more times, and the exposure timing is also shown in FIG.
Not limited to the case of 2, the image exposure may be performed by selecting an appropriate timing.

Further, another method for reducing the voltage of the photosensor will be described. By connecting an element composed of a resistor 70 and a capacitor 71 to the recording medium as shown in FIG. 16, it is possible to reduce the voltage applied to the optical sensor immediately after the voltage is applied. 16 shows a parallel circuit of a resistor and a capacitor, the same effect can be obtained by connecting only the resistor.

In order to investigate the effect of the external connection element, the equivalent circuit model was used to simulate the voltage change applied to the optical sensor and the liquid crystal medium. FIG. 17 shows an equivalent circuit model used in the simulation. As shown in FIG. 17, the liquid crystal medium and the optical sensor are represented as a parallel circuit of a resistor and a capacitor, respectively, and a resistor R _eX and a capacitor C _eX are connected as external connection elements. In addition, the internal resistance of the power supply is R _int . The physical properties used in the calculations are as follows.

Optical sensor resistance: 200 MΩ Optical sensor capacity: 50 pF Liquid crystal medium resistance: 600 MΩ Liquid crystal medium capacity: 160 pF External element resistance: 50 MΩ External element capacity: 50 pF Power supply internal resistance: 1 MΩ FIG. Indicates.
The applied voltage was 400 V when an external element was connected, and 370 V when it was not connected at a constant voltage.
The time required to reach the threshold voltage of the liquid crystal medium was 50 msec under normal voltage application conditions and 67 msec when an external element was connected.

Further, FIG. 19 shows the time change of the voltage applied to the optical sensor at this time. Under normal voltage application conditions, a voltage of about 280 V is applied to the photosensor immediately after the voltage is applied, but when an external element is connected, a maximum of 220 V is applied.
It turns out that it only takes about V. This is because, as shown in FIG. 20, a large voltage is applied to the external element immediately after the voltage is applied and the external element is attenuated thereafter. When the external element is not connected, the voltage applied to the internal resistance of the power source is attenuated in an extremely short time as shown in FIG. 20, so that the effect of reducing the voltage of the optical sensor cannot be obtained. Here, the parallel circuit of the resistor and the capacitor has been described as an example, but the same effect can be obtained when only the resistor is connected.

[0023]

As described above, according to the present invention, the voltage applied between the photosensor and the electrode of the liquid crystal recording medium is set to be higher at the end of voltage application than at the start of voltage application. As a result, the voltage applied to the photosensor immediately after the voltage is applied can be lowered to reduce the occurrence of abnormal discharge, noise, and defects.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an information recording device.

FIG. 2 is a diagram showing a configuration of a laminated recording medium.

FIG. 3 is a diagram illustrating recording of exposure information.

FIG. 4 is a diagram illustrating reproduction of exposure information.

FIG. 5 is a diagram showing a current measuring device flowing through an optical sensor having a pseudo liquid crystal medium.

6 is a diagram showing current measurement results of an exposed portion and an unexposed portion by the apparatus of FIG.

FIG. 7 is a diagram showing a calculation result of a voltage applied to a pseudo liquid crystal medium.

FIG. 8 is a diagram showing a calculation result of a voltage applied to an optical sensor.

FIG. 9 is a diagram showing an example of a voltage applying method for reducing the voltage applied to the optical sensor.

10 is a diagram showing calculation results of voltages applied to the pseudo liquid crystal medium and the optical sensor when the sloped voltage of FIG. 9 is applied.

FIG. 11 is a diagram showing a result of calculating a potential difference between bright and dark in the measurement results of FIGS. 8 and 10.

FIG. 12 is a diagram showing another example of voltage application conditions for reducing the voltage of the optical sensor.

FIG. 13 is a diagram showing a calculation result of a voltage applied to a pseudo liquid crystal medium.

FIG. 14 is a diagram showing a calculation result of a voltage applied to an optical sensor.

FIG. 15 is a diagram showing calculation results of a potential difference between a bright portion and a dark portion of the photosensor under the conditions A and B.

FIG. 16 is a diagram showing an example in which an external element is connected to reduce the voltage applied immediately after the voltage is applied to the optical sensor.

FIG. 17 is a diagram showing an equivalent circuit when an external element is connected.

FIG. 18 is a diagram showing a calculation result of time change of voltage applied to a liquid crystal medium when an external element is connected and when a normal voltage is applied.

FIG. 19 is a diagram showing a calculation result of a time change of a voltage applied to an optical sensor when an external element is connected and when a normal voltage is applied.

FIG. 20 is a diagram showing a voltage applied to an external element when the external element is connected and a voltage change when the external element is not connected.

[Explanation of symbols]

10 ... Optical sensor, 14 ... Electrode, 20 ... Liquid crystal recording medium, 3
0 ... Power supply, 50 ... Electrodes for current measurement, 51, 70 ... Resistance,
52, 71 ... Capacitors.

Claims (8)

[Claims] 1. An optical sensor having a photoconductive layer on an electrode and a liquid crystal recording medium having a liquid crystal-polymer composite layer on the electrode are arranged to face each other via an air gap or a transparent electrode on a support. Layer, a photosensor in which a photoconductive layer is laminated, and a liquid crystal recording medium in which a liquid crystal-polymer composite layer is laminated on an electrode layer are directly or through an intermediate dielectric layer to an integrated information recording medium In the method of recording an image by aligning the liquid crystal by applying a voltage between the photosensor and the electrode of the liquid crystal recording medium by imagewise exposing the photoconductive layer, the voltage applied between the electrode of the photosensor and the liquid crystal recording medium is changed. The image recording method is characterized by increasing the voltage at the end of voltage application to be higher than immediately after the start of voltage application. 2. The image recording method according to claim 1, wherein the voltage applied between the photosensor and the electrode of the liquid crystal recording medium is monotonically increased from the start of the voltage application to the end of the voltage application. 3. The image recording method according to claim 1, wherein the voltage applied between the photosensor and the electrode of the liquid crystal recording medium is increased stepwise from the start of voltage application to the end of voltage application. . 4. An optical sensor having a photoconductive layer on an electrode and a liquid crystal recording medium having a liquid crystal-polymer composite layer on the electrode are arranged to face each other via an air gap, or a transparent electrode on a support. Layer, a photosensor in which a photoconductive layer is laminated, and a liquid crystal recording medium in which a liquid crystal-polymer composite layer is laminated on an electrode layer are directly or through an intermediate dielectric layer to an integrated information recording medium In the method of recording an image by exposing the photoconductive layer to an image and applying a voltage between the photosensor and the electrode of the liquid crystal recording medium to orient the liquid crystal, an impedance element composed of a resistor or a resistor and a capacitor is used as a power source and the liquid crystal recording. An image recording method, characterized in that the voltage is applied to the optical sensor to reduce the voltage applied to the medium. 5. An optical sensor having a photoconductive layer on an electrode and a liquid crystal recording medium having a liquid crystal-polymer composite layer on the electrode are arranged to face each other via an air gap, or a transparent electrode on a support. Layer, a photosensor in which a photoconductive layer is laminated, and a liquid crystal recording medium in which a liquid crystal-polymer composite layer is laminated on an electrode layer are directly or through an intermediate dielectric layer to an integrated information recording medium In a device for recording an image by exposing a photoconductive layer to an image and applying a voltage between the electrodes of the photosensor and the liquid crystal recording medium to record an image, a power source connected between the electrodes of the photosensor and the liquid crystal recording medium. Is
An image recording apparatus, which is a power supply capable of obtaining an output voltage such that the voltage at the end of voltage application is higher than that at the beginning of voltage application. 6. The image recording apparatus according to claim 5, wherein the output voltage monotonically increases. 7. The image recording apparatus according to claim 5, wherein the output voltage increases stepwise. 8. An optical sensor having a photoconductive layer on an electrode and a liquid crystal recording medium having a liquid crystal-polymer composite layer on the electrode are arranged to face each other via an air gap or a transparent electrode on a support. Layer, a photosensor in which a photoconductive layer is laminated, and a liquid crystal recording medium in which a liquid crystal-polymer composite layer is laminated on an electrode layer are directly or through an intermediate dielectric layer to an integrated information recording medium In an apparatus for recording an image by imagewise exposing the photoconductive layer and applying a voltage between the photosensor and the electrode of the liquid crystal recording medium, an impedance element composed of a resistor or a resistor and a capacitor is used as a power source and the recording medium. An image recording device characterized by being connected between them.