JP3312704B2 - Information recording method and apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording method and apparatus for recording an image by changing the orientation of a liquid crystal recording medium.

[0002]

2. Description of the Related Art Conventionally, a polymer-dispersed liquid crystal recording medium in which a liquid crystal layer in which liquid crystal is dispersed and fixed in a resin is formed on an electrode, and an optical sensor in which a photoconductive layer is formed on the electrode layer are opposed to each other. A device that records an image by voltage application exposure is known. FIG. 1 shows the configuration of an image recording apparatus using such a polymer-dispersed liquid crystal recording medium. In the figure, reference numeral 10 denotes an optical sensor, and reference numeral 20 denotes a liquid crystal 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 in a liquid crystal recording medium 20, a transparent electrode 22 and a polymer dispersed liquid crystal layer 23 are sequentially laminated on a transparent support 21. I have. The photoconductive layer 13 has a single layer structure in which trinitrofluorenone is added to polyvinyl carbazole as an organic photoconductive layer, or an azo pigment as polyvinyl butyral as a charge generation layer. And the like, and a layer obtained by laminating a material in which a hydrazone derivative is mixed with a resin such as polycarbonate as a charge transfer layer can be used.

A photosensor and a liquid crystal recording medium as shown in FIG. 1 are opposed to each other through a gap of about 10 μm using a spacer such as polyethylene or polyimide, and a voltage application exposure is performed. As shown in FIGS. 2A and 2B, a structure in which an optical sensor and a liquid crystal recording medium are laminated has been proposed.
As shown in FIG. 2A, there are a type in which a liquid crystal recording layer is directly laminated on an optical sensor, and a type in which a transparent dielectric intermediate layer 24 is interposed as shown in FIG. 2B.

[0004] Such an optical sensor 10 and the liquid crystal recording medium 2
0 are arranged opposite to each other, and as shown in FIG. 3, when a voltage is applied between the two electrodes 12 and 22 by the power supply 30 and visible light is irradiated as writing light, the conductivity of the photoconductive layer 13 is changed according to the exposure intensity. Then, the electric field applied to the liquid crystal layer 23 changes, and the orientation state of the liquid crystal layer changes. This state is maintained even after the applied voltage is turned off and the electric field is removed, and image information is recorded.

In order to read recorded image information, for example, as shown in FIG. 4, a liquid crystal recording medium 20 is irradiated with reading light by a light source 40, and the transmitted light is read by a photoelectric conversion device 60 and converted into an electric signal. It is done by doing. 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 as the readout light to be applied to the liquid crystal recording medium, it is desirable to select and irradiate an appropriate wavelength light by the filter 50. The incident light is modulated by the orientation of the liquid crystal layer of the liquid crystal recording medium,
The transmitted light is a photoelectric conversion device 60 such as a photodiode.
Is converted into an electric signal, and the converted electric signal is output to a printer or a CRT as needed.

[0006]

FIG. 5 shows time on the horizontal axis and the degree of modulation on the vertical axis, and shows an exposed portion (bright portion) and an unexposed portion (dark portion).
, And the difference between the modulation degrees of the bright part and the dark part is the contrast, whereby the image is recorded. In the part exposed to light, the conductivity of the photoconductive layer of the photoreceptor increases, an extra voltage is applied to the liquid crystal part, and the liquid crystal operates faster than the part not exposed to light. Therefore, an image can be recorded using the difference in the operation speed.
For example, when the voltage is turned off for a certain time, the operation of the liquid crystal recording medium stops at that moment, and the image information is stored. As can be seen from FIG. 5, the time for turning off the voltage has an optimum value. If the time for turning off the voltage is too early, for example, t1, the bright portion of the liquid crystal recording medium will not be sufficiently modulated. High contrast cannot be obtained. On the other hand, if the voltage application time is too long, for example, as at t3, the dark portion of the liquid crystal recording medium will be modulated too much, so that sufficient contrast will not be obtained and a high quality image will not be obtained. in this way,
In order to obtain a high-quality image, it is necessary to set an optimal voltage application time (t2 in the figure), but it is very difficult to accurately predict before applying a voltage.

As an accurate setting method of the voltage application time,
A method of monitoring the transmittance of the liquid crystal recording layer to stop the voltage according to the transmittance has already been proposed. However, in the method of monitoring the transmittance, a function of measuring the transmittance is added to the information recording apparatus. Then, there is a problem that the device becomes large-scale, and the transmittance of the liquid crystal recording layer needs to be corrected because the wavelength dependency of the monitor light is large. The present invention has been made in view of the above point, and an object of the present invention is to provide an information recording method and an information recording apparatus in which voltage application is stopped at an optimal voltage application time and information with sufficient contrast can be recorded.

[0008]

For this purpose, the present invention measures the current in a dark part when applying a voltage using a polymer-dispersed liquid crystal recording medium, monitors the operation of the liquid crystal recording layer, and adjusts the contrast. It is characterized in that the voltage is turned off by detecting the moment when it becomes maximum.

[0009]

According to the present invention, the operation of the liquid crystal recording layer is monitored by measuring the current flowing through the liquid crystal recording medium. For example, when the voltage of the unexposed portion reaches the threshold value of the liquid crystal recording medium by current measurement, the time change of the current of the exposed portion, or the time change of the current difference between the exposed portion and the unexposed portion, It is monitored that the contrast in the dark area is maximized and that the difference between the integrated value of the current in the light-irradiated area and the integrated value of the current in the unexposed area has reached an amount corresponding to the change in the capacity of the liquid crystal recording medium. By stopping the voltage application, it is possible to perform image information recording with the maximum contrast.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a method, a medium, and a measuring apparatus for measuring a current value when information is recorded on an information recording medium by voltage application exposure will be described. FIG. 6 shows a method for measuring the current in the unexposed portion. As shown in the figure, a mask 14 is formed on a part of the surface of the transparent support of the photoreceptor 10 so that light does not reach the photoconductive layer in this region. There is no particular limitation on the mask 14 as long as it blocks light, and a black paint is applied or an Al deposited film is used. In this case, the transparent electrode of the photoreceptor is, as shown in FIGS.
The image information recording part and the current value monitoring part are separated.
In this figure, the electrodes on the photoreceptor side are formed separately, but the electrodes of the liquid crystal recording medium may be separated. As shown in the figure, different power supplies may be used for the image information recording portion and the current value monitor portion, or a common power source may be used. A current monitoring resistor 40 is connected between the electrode 12b of the monitor portion and the power supply, and the current can be measured by monitoring the voltage of the resistor 40. The resistor 40 varies depending on the area of the monitor portion and the conductivity of the photoconductor, but a resistor of about 1 kΩ to 1 MΩ can be used.

FIGS. 7 (a) and 7 (b) show a method for simultaneously measuring the current values of an exposed portion and an unexposed portion.
The transparent electrodes of the photoreceptor are formed separately in three regions as shown in FIG. 12a, 12b and 12c, so that a voltage can be applied independently of each other. Resistors 40b and 40c are connected to the current monitoring electrodes 12b and 12c in the unexposed and exposed portions, respectively, and the current can be monitored by measuring the voltage of each resistor. As in FIG. 6, a shielding mask 14 is formed on the surface of the support of the photoconductor corresponding to the unexposed portion current monitor area.

As shown in FIG. 8A, a method of irradiating light to a current monitor area of an exposed portion is to use a shutter 52, a lens system 70, a semi-reflective mirror 53, and a mirror 54 for part of image exposure light. The optical system includes a method of irradiating the current monitor portion and a method of irradiating with an optical system including a shutter 53 and a lens system 71 different from the image exposure system as shown in FIG. Is also good. The amount of light applied to the monitor is adjusted to an appropriate amount by the lens system 71.

The method of monitoring the current by forming a current monitor area in an area different from the image recording portion has been described above. However, the voltage application time can be controlled by monitoring the current of the image recording portion. . In this case, it is considered that the current value when the average light amount of the recorded image is irradiated is measured. In the method in which the photoconductor and the liquid crystal recording medium are arranged opposite to each other via an air layer and a voltage is applied, a spacer film is arranged around the image recording portion in order to keep the air gap uniform. When measuring the current value, if a voltage is applied to the spacer portion, accurate current measurement cannot be performed. For example, as shown in FIG.
5 It is necessary to separate the arrangement portion and the formation portion of the electrode 12. In FIG. 9, a spacer 15 is arranged in a rectangular shape around the photosensitive member 10 and the liquid crystal recording medium 20, and image recording is performed at a central portion where the spacer 15 does not cover.

When both the current value of the image recording portion and the current value of the unexposed portion are monitored and the voltage application time is controlled, it is not always necessary to make the areas of the two equal, and in this case, the difference between the areas is reduced. By using the considered resistor, the calculation for control can be simplified. For example,
The electrode area of the image recording portion is Sa, the electrode area of the current monitor portion of the unexposed portion is Sf, and the resistance for monitoring is R.
Assuming that a and Rf, a resistor is selected as SaRa = SfRf, and the current per unit area can be directly compared by comparing the voltage of each resistor.

To control the voltage OFF time from the current measurement, it is necessary to measure the electrical properties of the liquid crystal recording layer. FIG. 10 shows a method for measuring the electrical properties of the liquid crystal recording layer.
An electrode 24 is formed on the surface of the liquid crystal recording layer, a resistance 41 for measuring current is connected, a pulse voltage lower than the threshold value of the liquid crystal recording medium is applied by the power supply 31, and the current value is monitored to monitor the liquid crystal recording layer. The resistance value can be determined.

Next, a method of controlling the voltage application time will be described.
This will be described with reference to the drawings by taking a separation type recording medium as an example. The system of the separation type recording medium is represented by an equivalent circuit shown in FIG. At the initial stage of the applied voltage, a voltage is applied to each of the photoconductor and the liquid crystal recording medium according to the ratio of the capacity. V _OPC (0) = V _AP × (C _LC / (C _OPC + C _LC )) (1-1) V _LC (0) = V _AP × (C _OPC / (C _OPC + C _LC )). 1-2) The liquid crystal recording layer is represented by a parallel circuit of a resistor and a capacitor,
The following differential equation holds. I = d (C _LC V _LC ) / dt + (V _LC / R _LC ) (1-3) When V _LC is lower than the threshold value of the liquid crystal recording medium, the liquid crystal recording medium does not operate. capacitance does not _{change, C LC = const ...... (1-4} ) I = C LC (dV LC / dt) + (V LC / R LC) ...... (1-5) V LC (t + Δt) = V LC (t) + (dV _LC / dt) · Δt (1-6) From equations (1-3) and (1-6), V _LC (t + Δt) = V _LC (t) + (I (t) − V _LC (t) / R _LC ) Δt / C _LC (1-7) The voltage applied to the liquid crystal recording layer is calculated by substituting the initial condition of the expression (1-2) into the expression (1-7). You can ask. Equation (1-2), in (1-7), the liquid crystal recording layer, the capacity previously measurable deli photoconductive layer, or the resistance R _LC of the liquid crystal recording layer measured beforehand, or shown in FIG. 10 Can be measured immediately before recording an image by the above method. At the time of image recording, the current I (t) in the dark part can be measured by the method shown in FIG.

As can be seen from FIG. 5, in order to obtain a high-quality image having a large contrast, the voltage is turned off when the voltage of the liquid crystal recording medium reaches a threshold value and is slightly aligned (about 10 to 20%). There is a need. Since the liquid crystal in the dark part hardly aligns before the voltage is turned off, the capacity of the liquid crystal recording layer is considered to be substantially constant, and the equation (1-7) is satisfied.
By turning off the voltage after the voltage of the liquid crystal recording layer obtained by measuring the dark current value reaches the threshold voltage, a high-contrast image can be obtained. The liquid crystal recording layer in the dark part is oriented to some extent (about 10 to 20% of the state in which the liquid crystal is completely oriented) rather than not being oriented at all.
Since a better image can be obtained by performing FF, it is better to turn off the voltage after a certain time has elapsed after reaching the threshold voltage.

As another method of controlling the voltage application time, there is a method of detecting a change in capacitance of the liquid crystal recording layer from a dark current value. In the liquid crystal recording layer, the liquid crystal does not align below the threshold voltage, and the capacitance does not change. Therefore, the equation (1-5) is satisfied. During the voltage application, the voltage of the liquid crystal recording layer monotonically increases, and the measured current The value decreases monotonically. When a voltage equal to or higher than the threshold voltage is applied, the liquid crystal is oriented in the direction of the electric field, and the capacity of the liquid crystal recording layer changes. Therefore, the equation (1-3) is expressed as There is. _{I = C LC (dV LC /} dt) + V LC in the case where the capacity of the _{(dC LC / dt) + (} V LC / R LC) ... (1-8) liquid crystal recording layer is changed, the formula (1-8) The current according to the capacitance change of the second term flows. Since the liquid crystal has a higher dielectric constant in the aligned state than in the non-aligned state, the capacity of the liquid crystal recording layer increases when the liquid crystal is aligned. By utilizing this fact, by detecting a change in current value due to a change in capacitance, a change in capacitance (alignment) of the liquid crystal can be detected.

FIG. 12 is a diagram showing a method of measuring a change in capacitance and a current value of the liquid crystal recording layer in the present invention. The photoconductive layer is prevented from being irradiated with light either by forming a mask 14 on the transparent support of the optical sensor 10 or performing the measurement in a dark place. The reflection film 16 is formed on the liquid crystal recording layer surface or the photoconductive layer surface of the optical sensor.
The reflective film needs to be formed very thin (1000 ° or less) so as not to affect the recording characteristics of the system.
The optical sensor and the liquid crystal recording medium are arranged to face each other as shown in the figure, and the photodiode 80 and the photoelectric conversion element 81 are changed by the light from the photodiode reflected by the reflection film 16.
It is installed so that it is irradiated. When a reflective film is not formed on the photoconductive layer, care must be taken so that the light from the photodiode is not exposed to the light sensor. The optical sensor and the liquid crystal recording layer are arranged via an air gap, and a voltage is applied by a power supply 30. The current can be measured by monitoring the voltage of the resistor 40. When the liquid crystal is aligned and the transmittance of the liquid crystal layer changes, the photoelectric conversion element 81
The amount of light applied to the light source changes and is converted into an electric signal for monitoring. A method for measuring the relationship between the signal of the photoelectric conversion element and the capacity of the liquid crystal recording layer will be described later in detail. FIG. 13 shows the change in the capacity of the liquid crystal recording layer measured in this manner.
FIG. 14 shows the current values measured at this time. All values are converted per unit area (cm ² ).

FIG. 15 shows the time change of the measured value of the current in the dark part with respect to time. When the liquid crystal does not align below the threshold voltage of the liquid crystal, the current value monotonously decreases, and the differential value is a negative value. When the liquid crystal starts to be aligned, the capacitance changes, so when the change amount is large, the second term of the expression (1-8) increases, the current increases, and the differential value becomes larger than zero. The liquid crystal recording layer is 20 ms
The threshold voltage is reached near ec and the operation starts. 60m
Since the change amount of the liquid crystal recording layer increases from around sec,
Since the portion corresponding to the capacitance change in the second term of the equation (1-8) becomes large and the current starts to increase, the differential value changes from negative to positive. In this way, by monitoring the current value, it is possible to monitor the change in the capacity of the liquid crystal recording layer from the differential value. As a method of controlling the voltage application time at this time, the voltage is changed to O at the timing when the current in the dark part changes from decreasing to increasing (the differential changes from negative to positive).
By performing FF, a high-contrast image can be obtained.

Next, a method of controlling the voltage application time by measuring the current of the exposed portion will be described. First, FIG. 16 shows a method for measuring the current (exposure change) and the modulation (capacity change) of the liquid crystal medium in the exposure unit. The basic measurement method is the same as that of FIG.
In FIG. 6, a point for irradiating the optical sensor with light for a certain period of time is added by the light source 50 and the optical shutter 51.
FIGS. 17A and 17B show measurement results of current characteristics A when light was irradiated for 1/60 sec (exposed portion) and current characteristics B when light was not irradiated (unexposed portion). The difference (A-B) between the current value of the portion and the unexposed portion is shown. FIG.
(A) and 18 (b) show the modulation of the liquid crystal medium (capacity change: unexposed portion C1, exposed portion C2) and the difference (C1-C2) between the capacity of the unexposed portion and the exposed portion at this time. In each case, the values are converted per unit area. In the exposed portion, a larger amount of current flows than in the unexposed portion, and an extra voltage is applied to the liquid crystal portion, so that the light is modulated faster. As can be seen from the figure, the difference between the current values of the exposed part and the unexposed part shown in FIG. 17B increases from the start of voltage application to the end of light irradiation (time t1). Although the photocurrent continues to flow even after the end of the light irradiation, the current difference between the exposed part and the unexposed part decreases after the light irradiation is stopped. Thereafter, when the liquid crystal recording layer is modulated in the exposed portion, a current corresponding to the capacitance change expressed by the second term of the equation (1-8) flows, so that the current difference between the exposed portion and the unexposed portion starts increasing again ( Time t2). Further, when the liquid crystal recording layer in the unexposed portion starts to be modulated, a current due to the capacitance change flows, and the current difference starts to decrease (time t).
3).

Next, FIG. 19 shows the differential value of the current difference between the exposed part and the unexposed part. From FIG. 18B, the difference in modulation (difference in capacitance) between the unexposed portion and the exposed portion is 55 to 70 msec and the voltage O
It becomes the largest when the FF is performed, but coincides with the time when the differential value of the current difference in FIG. 19 is minimum. FIG. 20 shows the change over time of the derivative of the current value of the exposed portion. Since the minimum value in FIG. 19 substantially matches the minimum value in FIG. 20, it can be seen that the current value depends on the operation of the liquid crystal recording layer in the exposed portion. That is, it is considered that the amount of change in the modulation of the liquid crystal recording layer in the exposed portion is not constant, but sharply modulates to a certain extent, but the modulation speed is decreased at a rate higher than this, so that such current characteristics are considered to be exhibited.

As described above, by turning off the voltage at the timing when the current difference between the exposed part and the unexposed part or the differential value of the current in the exposed part takes a minimum value after the end of the exposure,
The voltage application can be stopped in a state where the modulation speed of the exposed portion is reduced, that is, in a state close to a state where the alignment is completely performed, and image recording can be performed under a condition where a high-contrast image can be obtained. At this time, as the exposure intensity of the exposure unit, a light amount with an extremely low intensity is not preferable, and it is preferable to measure a current value for an intensity of 80% or more of the light amount corresponding to the maximum exposure amount of an image.

Next, as another method of controlling the voltage application time by measuring the current value, a method of integrating the difference between the current values of the exposed portion and the unexposed portion will be described. FIG.
7, the result of calculating the voltage applied to the liquid crystal recording layer from the measurement results of FIG. 18 from the equation (1-8), and FIG. 21B shows the time change of the potential difference between the exposed part and the unexposed part. FIG. 21 (b)
As can be seen, the potential difference between the exposed portion and the unexposed portion of the liquid crystal medium initially increases, but the liquid crystal layer in the exposed portion modulates quickly and the capacitance changes, so the potential difference decreases with this,
It becomes almost zero near the time when the capacity difference between the exposed part and the unexposed part becomes maximum. At this time, the voltage of the liquid crystal recording layer in the exposed part and the unexposed part is substantially equal to the threshold voltage, and the difference between the amounts of charges charged in the liquid crystal recording layer in the exposed part and the unexposed part is expressed by the following equation.

ΔQ = V _TH ΔC (1-9) ΔC is the capacitance difference between the exposed part and the unexposed part, V _TH is the threshold voltage of the liquid crystal recording layer. The relationship between the current value and the expression (1-9) is represented by the following expression. ∫ (I _photo −I _dark ) dt−∫ (ΔV / R _LC ) dt = ΔQ (1-10) where R _LC is the resistance of the liquid crystal recording layer, and ΔV is the potential difference between the exposed part and the unexposed part. . In the expression (1-10), the value of ΔQ on the right side is, for example, when the exposure intensity is a certain value, it is possible to predict the degree of modulation between the exposed portion and the unexposed portion, and the threshold voltage is also known. , By measuring the light intensity (1
-9) can be estimated. Also, (1-1)
The part leaking from the resistance component of the liquid crystal recording layer in the second term of the equation (0) can also be estimated in advance. Therefore, the difference between the current in the exposed part and the current in the unexposed part is accumulated, and the value (charge amount) is calculated. If the voltage application is stopped at the time when the capacity difference between the exposed portion and the unexposed portion becomes the amount corresponding to the difference in the charge amount when the maximum is obtained,
High contrast images can be obtained. In this case, the light intensity of the exposed portion is not particularly limited. For example, when measuring the current value of a portion irradiated with a light amount of 50% of the maximum light amount, the capacity of the liquid crystal layer when completely aligned, The threshold voltage may be multiplied by 50% of the difference between the capacities of the liquid crystal recording layers in the non-aligned state. In addition, the light intensity of the current measurement portion does not need to be uniform over the entire measurement area, and the average value of the current value is measured, so that the average light amount can be estimated. In addition, as the current measurement portion, the exposure portion does not necessarily need to be provided separately from the image recording portion, and if the average light intensity can be measured,
The measurement may be performed for the entire image recording portion.

As described above, the operation of the liquid crystal recording layer can be monitored by monitoring the current in the exposed portion and the unexposed portion, and the voltage is turned off with an appropriate voltage application time. Image can be obtained. The process of measuring the current to monitor the operation of the liquid crystal recording layer and obtaining the optimum voltage application time is performed by using a control device such as a microcomputer. To turn off the voltage
To do it.

Next, a method for measuring the relationship between the change in capacitance and the change in transmittance of the liquid crystal recording layer will be described. FIG. 22 shows a measuring method. A gold electrode 24 is formed on the surface of the liquid crystal recording layer of the liquid crystal recording medium, and a voltage is applied between the gold electrode 24 and the transparent electrode 22 by a pulse generator (power supply in the figure) and an amplifier. As in FIG.
The LED 80 and the photoelectric conversion element 81 are installed so that the light of the LED is reflected by the gold electrode and is incident on the photoelectric conversion element as shown in the figure, and the change in the transmittance of the liquid crystal recording layer is monitored. A voltage as shown in the following equation is applied to the liquid crystal recording layer, and V (t) = αt (1-11) As a result of measuring a current value, a current as shown in FIG. 23 is measured. . Since the liquid crystal recording layer is considered as a parallel circuit of a capacitor and a resistor, the current is given by the following equation. _{I (t) = C LC (} dV LC / dt) + V LC (dC LC / dt) + V LC / R LC ...... (1-12) (1-11) from _{equation, dV LC / dt = α ......} ( 1-13) In addition, since the resistance R _LC of the liquid crystal recording layer can also be estimated from the gradient of the current, the result of the current measurement is compared with the signal of the photoelectric conversion element to determine the change in transmittance and the change in capacitance. You can estimate the relationship. FIG. 24 shows the signal of the photoelectric conversion element monitored at this time. Compared with the measurement current, a peak current is observed in the current measurement at a voltage at which the signal of the photoelectric conversion element changes (corresponding to a change in transmittance).
This indicates that the change in the transmittance of the liquid crystal recording layer and the change in the capacitance correspond to each other. By comparing the two, the correlation between the change in the capacitance and the transmittance monitor signal can be obtained.

[0028]

As described above, according to the present invention, the exposure section,
By monitoring the current in the unexposed area, the state of operation of the liquid crystal recording layer is monitored, and the voltage is changed to O with an appropriate voltage application time.
By performing FF, a good image with high contrast can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing a structure of a liquid crystal recording medium.

FIG. 2 is a diagram showing a structure of a liquid crystal recording medium.

FIG. 3 is a diagram illustrating an image recording method of the present invention.

FIG. 4 is a diagram illustrating an image reading method.

FIG. 5 is a diagram showing a temporal change of a modulation degree in an exposed portion and an unexposed portion.

FIG. 6 is a diagram illustrating a method of measuring a current in a separation type information recording medium.

FIG. 7 is a diagram illustrating a method for simultaneously measuring currents in an image recording unit and a current monitoring unit.

FIG. 8 is a diagram illustrating a method of irradiating light to a current monitor area of an exposed portion.

FIG. 9 is a diagram illustrating a method of measuring a current value of an image recording portion separately from a spacer portion.

FIG. 10 is a diagram showing a method for measuring the electrical properties of a liquid crystal recording layer.

FIG. 11 is a diagram showing an equivalent circuit in the case of a separation type liquid crystal recording medium.

FIG. 12 is a diagram showing a method of measuring a change in capacitance and a current value of a liquid crystal recording layer.

FIG. 13 is a diagram showing a change in capacitance of a liquid crystal recording layer.

FIG. 14 is a diagram showing a change in a current value when a capacitance of a liquid crystal recording layer changes.

FIG. 15 is a diagram showing a time differential characteristic of a current measurement value in a dark part.

FIG. 16 is a diagram showing a method of measuring a current of an exposed portion and a change in capacitance of a liquid crystal medium.

FIG. 17 is a diagram showing the results of current measurement on exposed and unexposed areas.

FIG. 18 is a diagram showing modulation (capacity change) of a liquid crystal medium in an exposed portion and an unexposed portion.

FIG. 19 is a diagram showing a differential value of a current difference between an exposed portion and an unexposed portion.

FIG. 20 is a diagram showing a time change of a current differential value of an exposure unit.

FIG. 21 is a diagram showing a voltage applied to a liquid crystal layer obtained from a current measurement result of an exposed portion and an unexposed portion and a change in capacitance.

FIG. 22 is a diagram illustrating a method for measuring the relationship between a change in capacitance and a change in transmittance of a liquid crystal recording layer.

FIG. 23 is a diagram showing voltage-current characteristics of a liquid crystal recording layer.

FIG. 24 is a diagram illustrating transmittance characteristics with respect to a voltage change.

[Explanation of symbols]

10 optical sensor, 11 transparent support, 12 transparent electrode
12a: Image recording electrode, 12b, 12c: Current measuring electrode, 13: Photoconductive layer, 14: Mask, 15: Spacer, 20: Liquid crystal recording medium, 21: Transparent support, 22: Transparent electrode, 23: High Molecular dispersed liquid crystal layer, 24 ... electrode, 30 ...
Power supply, 40, 40a, 40b, 41 ... resistance for current measurement,
80 ... LED, 81 ... Photoelectric conversion element.

Claims (18)

(57) [Claims] 1. A photoconductor in which a transparent electrode and a photoconductive layer are sequentially laminated on a transparent support, and a liquid crystal recording medium in which a transparent electrode and a polymer dispersed liquid crystal layer are sequentially laminated on the transparent support are opposed to each other. In the method of arranging and exposing an image by applying a voltage between both electrodes and orienting the liquid crystal to record information, the operation of the liquid crystal recording layer is monitored by measuring a current flowing through the liquid crystal recording medium. And controlling the voltage application time. 2. The information recording method according to claim 1, wherein the application of the voltage is stopped at a time when it is estimated that the voltage of the unexposed portion has reached the threshold value of the liquid crystal recording medium. 3. The information recording method according to claim 1, wherein the time when the contrast between the bright part and the dark part becomes maximum is monitored from the time change of the current in the exposed part, and the voltage application is stopped. . 4. The method according to claim 1, wherein the time when the contrast between the bright portion and the dark portion is maximized is monitored from the time change of the current difference between the exposed portion and the unexposed portion, and the voltage application is stopped. Characteristic information recording method. 5. The method according to claim 1, wherein a light having a predetermined exposure intensity is irradiated to the current measurement area, and a difference between an integrated value of the current in the light irradiation area and an integrated value of the current in the unexposed area is determined. An information recording method, comprising: stopping voltage application at a time when an amount corresponding to a change in capacitance is reached. 6. The information recording method according to claim 1, wherein the operation of the liquid crystal recording medium in the unexposed portion is monitored from the differentiation of the current value in the unexposed portion to control the voltage application. 7. The information recording method according to claim 1, wherein
An information recording method, comprising forming an electrode on the surface of a liquid crystal recording layer of a liquid crystal recording medium, applying a voltage to the liquid crystal recording medium before measuring information, and measuring a resistance value of the liquid crystal recording medium from a current value. 8. The information recording method according to claim 1, wherein
An information recording method, comprising: forming an electrode on the surface of a photoconductive layer of a photoreceptor, and applying a voltage to the photoreceptor to measure a current value before recording information. 9. A photoconductor in which a transparent electrode and a photoconductive layer are sequentially laminated on a transparent support, and a liquid crystal recording medium in which a transparent electrode and a polymer dispersed liquid crystal layer are sequentially laminated on the transparent support are opposed to each other. In a device that arranges, applies voltage between both electrodes, performs image exposure, aligns liquid crystal, and records information, a current monitoring resistor connected between the power supply and the photoconductor and a current monitoring resistor An information recording device comprising: a control unit for measuring a current value flowing through a circuit from the voltage, monitoring an operation state of the liquid crystal recording layer from the measurement result, and controlling a voltage application time. 10. The information recording apparatus according to claim 9, wherein a mask is formed on a part of the surface of the photosensitive member on the exposure side, and a current value in a region shielded by the mask is measured. . 11. The information recording apparatus according to claim 10, wherein an electrode of a photoconductor or a liquid crystal recording medium in a region where the mask is formed is formed separately from an image exposed portion. 12. The apparatus according to claim 9, wherein a current monitor region is formed in the image exposed portion, and a current monitor resistor is connected to each of the portion where the mask is formed and the current monitor region of the image exposed portion. An information recording device characterized by the above-mentioned. 13. The apparatus according to claim 12, wherein a resistance value of a current monitoring resistor connected to a current monitor region of a portion where a mask is formed and an image exposure portion is set to a value for correcting a difference in electrode area. An information recording device, comprising: 14. An information recording apparatus according to claim 13, further comprising an optical system for irradiating a predetermined amount of light to a current monitor area of an image exposed portion of the photosensitive member. 15. The apparatus according to claim 14, wherein an electrode formed on the photoconductor or the liquid crystal recording medium in the current monitor area of the image exposure portion of the photoconductor is formed separately from the image exposure portion. Characteristic information recording device. 16. The apparatus according to claim 14, wherein said optical system comprises a semi-reflective mirror for separating a part of the image exposure, and a lens system for condensing light from the semi-reflective mirror. Information recording device. 17. An information recording apparatus according to claim 14, wherein said optical system comprises an optical system different from an image exposure system for irradiating light corresponding to a light amount of a subject. 18. The apparatus according to claim 9, wherein a spacer for keeping an air gap is disposed between the photoconductor and the liquid crystal recording medium, and the electrode for current detection does not correspond to the spacer portion. An information recording device formed on a recording medium.