JPH0777701A - Information recording method and device which are adjustable in sensitivity and for which liquid crystal recording medium is used - Google Patents

Abstract

PURPOSE:To enable the correction of sensitivity in each of respective regions by dividing a recording region to plurality. CONSTITUTION:This information recording method comprises recording information by disposing an optical sensor formed with a photoconductive layer on a transparent electrode and a liquid crystal recording medium formed with a liquid crystal layer dispersed with liquid crystals in a resin on an electrode opposite to each other and impressing a voltage between both electrodes simultaneously with image exposing. At least one electrode on the optical sensor side or the liquid crystal recording medium side is divided to regions >=2, i.e., electrode 1, electrode 2 and the voltage is impressed to each electrode at or in the different voltage/impressed time.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a liquid crystal dispersed in a resin,
The present invention relates to a sensitivity-adjustable information recording method and apparatus using a fixed polymer-dispersed liquid crystal recording medium.

[0002]

2. Description of the Related Art FIG. 1 shows the structure of an image recording apparatus using a polymer dispersed liquid crystal medium. In the figure, 10 is an optical sensor and 20 is a liquid crystal recording medium. The optical sensor 10 includes a transparent support 12, a transparent electrode 12, and a photoconductive layer 1.
In the liquid crystal recording medium 20, the electrode 22 and the polymer dispersion type liquid crystal layer 23 are sequentially laminated on the support 21. As the photoconductive layer, amorphous selenium, amorphous silicon or the like as the inorganic conductive layer, a single layer of polyvinylcarbazole to which trinitrofluorenone is added as the organic photoconductive layer, or an azo-based pigment such as polyvinyl butyral as the charge generation layer It is possible to use, for example, a layer in which the hydrazone derivative is mixed with a resin such as polycarbonate as a charge transfer layer and which is laminated as a charge transfer layer. As the electrode 22 of the liquid crystal recording medium, a transparent electrode such as ITO or an opaque electrode such as A1 electrode can be used.

Such an optical sensor 10 and a liquid crystal recording medium 2
When 0s are arranged facing each other and a voltage is applied between the electrodes 12 and 22 by a power source 30 and visible light is irradiated as writing light as shown in the drawing, the conductivity of the photoconductive layer 13 changes according to the exposure intensity. Then, the voltage applied to the liquid crystal layer 23 changes, the alignment state of the liquid crystal layer changes, and the state is maintained even after the applied voltage is turned off to remove the electric field, and the image information is recorded.

The recording information thus recorded can be converted into an electric signal by a reading device as shown in FIG. That is, as for the light from the light source 40, only the light having an appropriate wavelength is irradiated onto the liquid crystal recording medium 20 through the filter 50. Since the liquid crystal recording medium has a different transmittance depending on the recorded information, it is modulated here, and the modulated light Is received by a photoelectric conversion device 60 such as a CDD line sensor and converted into an electric signal. This electric signal can be output by a CRT or a printer as needed.

[0005]

When a color image is to be recorded by such a method, the photosensors generally have different sensitivities to R, G and B, so that, for example, only the B channel becomes dark. Problems such as occur. First, the definition of sensitivity in the present invention will be described. Figure 3
Shows the results of simulations of the voltage applied to the liquid crystal recording medium when a voltage is applied in combination with the optical sensor, assuming that the optical sensor and the liquid crystal recording medium are parallel circuits of capacitors and resistors. Further, FIG. 4 shows the time change of the difference (potential difference) between the voltage of the exposed portion and the unexposed portion, which is obtained based on the result of FIG. The physical properties used in the calculation are as follows. (Value per 1 cm ² ) Liquid crystal recording medium resistance: 160 MΩ Liquid crystal recording medium capacity: 1000 pF Photosensor film thickness: 10 μm Photosensor conductivity: 1 × 10 ⁻⁵ A (at 300 V applied) Air gap: 10 μm Irradiation light amount: 30 Lx As shown in FIG. 3, in both the exposed portion and the unexposed portion, the voltage initially distributed in the capacity ratio is applied to the liquid crystal recording medium,
After that, it increases with time. Since the conductivity of the photosensor is higher in the exposed portion than in the unexposed portion, a voltage is applied to the exposed portion, which causes a potential difference with respect to the unexposed portion and changes the degree of orientation of the liquid crystal recording medium. When the voltage of the unexposed portion greatly exceeds the threshold value of the liquid crystal recording medium, the liquid crystal recording medium is oriented and transmitted, and the difference from the exposed portion becomes small. Therefore, an image can be recorded by turning off the voltage when the voltage of the unexposed portion exceeds the threshold value to some extent. At this time, the larger the potential difference between the exposed portion and the unexposed portion, the better the image with a large contrast can be obtained.
Further, it is considered that an optical sensor having high sensitivity can obtain a large contrast potential with a smaller amount of light. Since the optical sensor does not have a uniform spectral sensitivity in all visible light regions, when the light is divided into three channels of R, G, and B to be exposed in order to record a color image, it is not exposed to the exposed portion. There is a problem that the potential difference of the exposed portion differs for each color of R, G and B, and a good image cannot be obtained in a channel with low sensitivity.

To correct such a difference in sensitivity,
Using a conversion filter that uses different optical sensors so that the R, G, and B sensitivities are equal,
A method such as controlling the exposure amount according to the R, G, and B sensitivities can be considered, but it is difficult to select an optical sensor having the same R, G, and B sensitivities. It is not preferable to form different kinds of photoconductive layers on the optical sensor because it is difficult to manufacture. Then, there are not many kinds of filters that correct the difference in sensitivity among R, G, and B, and when such a filter is used, not only the light of the high-sensitivity channel but also the light intensity of the low-sensitivity channel It is also not preferable because it also lowers the overall sensitivity.

The present invention has been made in view of the above points, and the recording area can be divided into a plurality of areas, and the sensitivity can be corrected for each area. In the case of color image recording, the sensitivity is separately set for R, G, and B. An object of the present invention is to provide an information recording method and apparatus capable of adjusting sensitivity using a polymer dispersed liquid crystal recording medium that can be adjusted.

[0008]

The information recording method of the present invention comprises an optical sensor having a photoconductive layer formed on a transparent electrode, and a liquid crystal recording medium having a liquid crystal layer in which a liquid crystal is dispersed in a resin formed on the electrode. In the information recording method for recording information by arranging the two in opposition to each other and applying a voltage between both electrodes at the same time as image exposure, at least one electrode on the optical sensor side or the liquid crystal recording medium side is divided into two or more regions. It is characterized in that a voltage is applied to each of them at different voltages / application times. Further, in the information recording method of the present invention, the image light is divided into R, G and B channels, and the R, G and B channels are divided.
It is characterized in that different regions are irradiated with light for image exposure and the applied voltage / voltage application time is made different in each region. Further, in the information recording method of the present invention, the transmittance of the unexposed portion of the low sensitivity channel of the optical sensor is applied so as to be higher than that of the high sensitivity channel in accordance with the R, G, B spectral sensitivities of the optical sensor. It is characterized in that voltage / voltage application time is set. Further, the information recording method of the present invention is characterized in that the applied voltage / voltage application time is set so as to reduce the sensitivity of the channel having high sensitivity of the optical sensor in accordance with the R, G, B spectral sensitivity of the optical sensor. . In the information recording apparatus of the present invention, an optical sensor in which a photoconductive layer is formed on a transparent electrode and a liquid crystal recording medium in which a liquid crystal layer in which a liquid crystal is dispersed in a resin are formed on electrodes are arranged to face each other, and at the same time image exposure is performed. In an information recording apparatus for recording information by applying a voltage between both electrodes, at least one electrode of an optical sensor or a liquid crystal recording medium is divided into two or more areas, and different voltage / application is applied to each area. It is characterized in that it is provided with a power supply means for applying a voltage with time. In addition, the information recording apparatus of the present invention uses the image light R,
It is characterized in that a dividing means for dividing into three planes G and B is provided.

[0009]

According to the present invention, in image recording using a liquid crystal recording medium, the recording area is divided into a plurality of areas, and the applied voltage / voltage application time is varied for each area so that the sensitivity can be corrected. , R according to the spectral sensitivity of the optical sensor,
By correcting the sensitivity for each of the G and B lights, it is possible to record a high-quality color image.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the drawings. The following two methods are conceivable as a method of independently applying a voltage to each of the R, G, and B images and correcting the sensitivity. Even when the same liquid crystal recording medium and optical sensor are used, the potential difference between the exposed part (bright) and the unexposed part (dark) is different by changing the applied voltage and the voltage application time. The sensitivity can be corrected. FIG. 5 shows the time variation of the voltage applied to the liquid crystal recording medium when the applied voltage is 720 V and the other physical property values are the same as those in FIG. 3, and FIG. 6 shows the potential difference between the exposed portion and the unexposed portion at this time. Shows the change over time. FIG. 7 shows 720V, 750
The results of comparing the voltages of the liquid crystal media in the unexposed portions when V is applied are shown, and the results of the time difference in potential difference between the exposed portions and the unexposed portions at this time are shown in FIG. The physical property values are the same as those shown in FIGS.

As shown in FIG. 7, the voltage applied to the liquid crystal medium is higher when 750 V is applied than when 720 V is applied, and the threshold value (about 180 V) of the liquid crystal recording medium is applied when 720 V is applied. It takes about 45 msec to reach the threshold value, whereas the threshold value is about 30 msec when 750 V is applied. At this time, as shown in FIG. 8, there is almost no difference in the time change of the potential difference between the exposed portion and the unexposed portion, but the voltage is turned off at the threshold value of the liquid crystal medium (timing t1, t2 in FIG. 7). Then, there is a difference in potential difference (ΔV1, ΔV2 in FIG. 8) at that time.

As described above, even when the same optical sensor and liquid crystal recording medium are used, the magnitude of the potential difference between the exposed portion and the unexposed portion can be changed by changing the applied voltage. When using optical sensors with different sensitivities,
The voltage can be changed to reduce the potential difference of the channel with high sensitivity to the same level as the channel with low sensitivity.

Next, another method of sensitivity correction will be described. First, an image is recorded on the gray scale by using the apparatus shown in FIG. In FIG. 9, the light sensor 40 and the liquid crystal recording medium 20 are opposed to each other, and a voltage is applied between both electrodes by a power source 30, and a transparent original 70 (gray scale) is emitted by a light source 40.
The transmitted light image when illuminated is decomposed into R, G, and B light by the lens 50 and the three-sided decomposition prism 60 and irradiated, and the R, G, and B images are recorded at different positions on the liquid crystal recording medium 20.

FIG. 10 shows the relationship between the exposure amount and the transmittance for G light and R light after reading the image recorded on the liquid crystal recording medium after the projection exposure of the gray scale in this way, and the applied voltage is It is 720V. The exposure amount on the horizontal axis of the graph represents the transmittance of the transparent original used for image recording, and the vertical axis the transmittance is 100% when the liquid crystal recording medium is perfectly aligned with respect to ultraviolet light having a wavelength of 365 nm. Is shown as a relative value. As shown in FIG. 10, since the G sensor has a better G sensitivity than the R sensitivity, the image of the R light becomes dark.

FIG. 11 shows the results of comparing the R channel by changing the applied voltage at the same voltage application time. 7
When a voltage of 20 V is applied (◯ in the figure), the voltage is turned off when the threshold value of the liquid crystal recording medium is exceeded in the unexposed area, and the liquid crystal recording medium in the unexposed area does not change so much so that the transmittance is about 10%. Is low. In contrast, 750
In V application (● in the figure), if the voltage application time is the same, it takes some time after the threshold value is reached.
Even in the unexposed portion, the liquid crystal recording medium operates to some extent, and the transmittance is high and is about 20%. It can be seen from FIG. 11 that when 750 V is applied, the rise of the operation of the liquid crystal recording medium is on the low exposure side as compared with when 720 V is applied. FIG. 12 shows a comparison between the R channel 750V result and the G channel 720V result. It can be seen that the exposure areas recorded by both are almost the same. When a voltage of 750 V is applied, the read signal is slightly different because the transmittance of the unexposed portion is high, but the read signal is converted into a digital signal, so that the correction can be performed. Further, since the transmittance of the unexposed portion can be lowered by changing the wavelength of the reading light, the same correction can be performed.

As described above, the sensitivity can be corrected by changing the transmittance of the unexposed portion of the liquid crystal recording medium. However, as a method of changing the transmittance of the unexposed portion, the voltage is changed in this way. A method and a method of changing the voltage application time can be considered. In FIG. 13, when 720V and 750V are applied,
FIG. 8 is a graph similar to FIG. 7, showing a simulation result of the voltage applied to the liquid crystal recording medium. When a voltage of 720 V is applied and the voltage is turned off at time t2, the orientation of the liquid crystal recording medium hardly changes because it is the threshold value of the liquid crystal recording medium. When 750 V is applied, time t1
Since the liquid crystal recording medium operates until the threshold value is reached at t2, and the voltage is turned off at time t2, the transmittance is increased to some extent even in the unexposed portion. Similarly, even when a voltage of 720 V is applied, the liquid crystal recording medium changes between t2 and t3. Therefore, when the voltage is turned off at time t3, the transmittance of the unexposed portion increases. When changing the voltage application time, it is necessary to pay attention to the time change of the potential difference between the exposed portion and the unexposed portion, and the sensitivity can be corrected by the difference in the potential difference and both effects.

As a method of changing the applied voltage and the voltage application time, for example, as shown in FIG. 14, the same liquid crystal recording medium and photosensor are used, and two partial electrodes 1 are formed by patterning the electrodes. Divided into 2 electrodes, 2
Different voltages or voltage application times may be applied to the two power supplies 1 and 2. Of course, the division of the electrodes is not limited to the electrodes of the liquid crystal recording medium, but may be the electrodes on the photosensor side, or both electrodes may be divided.

As described above, when trying to record a color image, when the R, G and B sensitivities are different,
Sensitivity correction can be performed by independently applying voltages to the R, G, and B channels at different voltages and voltage application times.

[0019]

According to the present invention, the recording area can be divided into a plurality of areas, and the sensitivity can be corrected by varying the applied voltage / voltage application time for each area. R, G, B according to the spectral sensitivity of the optical sensor
The sensitivity can be corrected for each light, and a high quality color image can be recorded.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of image recording using a polymer-dispersed liquid crystal medium.

FIG. 2 is a diagram showing a configuration of a reading device.

FIG. 3 is a diagram showing a result of simulating a voltage applied to a liquid crystal recording medium when a voltage is applied in combination with an optical sensor.

FIG. 4 is a diagram showing a time change of a potential difference between an exposed portion and an unexposed portion obtained based on the result of FIG.

FIG. 5 is a diagram showing a time change of a voltage applied to a liquid crystal recording medium when an applied voltage is 720V.

FIG. 6 is a diagram showing a time change of a potential difference between an exposed portion and an unexposed portion in the case of FIG.

FIG. 7 is a graph showing a voltage applied to 720V and 750V.
It is a figure which shows the voltage change applied to the liquid crystal medium in an unexposed part.

FIG. 8 is a diagram showing a time change of a potential difference between an exposed portion and an unexposed portion in the case of FIG.

FIG. 9 is a diagram showing a configuration of an image recording apparatus.

FIG. 10 is a diagram showing the relationship between the exposure amount and the transmittance when projecting and exposing a gray scale for G light and R light.

FIG. 11 is a diagram showing a comparison result of changes in transmittance with respect to an exposure amount when R channel is applied with 750V and 720V.

FIG. 12 is a diagram showing a comparison result of changes in transmittance with respect to the exposure amount of R channel (application of 750 V) and G channel (application of 720 V).

FIG. 13 is a diagram showing simulation results of voltage applied to a liquid crystal recording medium when 720V and 750V are applied.

FIG. 14 is a diagram showing an example in which an electrode of a liquid crystal medium is divided into two and different applied voltages or voltage application times are applied.

[Explanation of symbols]

10 ... Optical sensor, 20 ... Liquid crystal recording medium, 30 ... Power supply, 4
0 ... Light source, 50 ... Lens, 60 ... Trihedral prism, 7
0: Transparent original (gray scale).

Claims (6)

[Claims] 1. An optical sensor in which a photoconductive layer is formed on a transparent electrode and a liquid crystal recording medium in which a liquid crystal layer in which a liquid crystal is dispersed in a resin is formed on an electrode are arranged to face each other, and at the same time image exposure is performed. In an information recording method for recording information by applying a voltage between them, at least one electrode on the optical sensor side or the liquid crystal recording medium side is divided into two or more regions, and different voltages / applications are applied to each region. An information recording method capable of adjusting sensitivity using a liquid crystal recording medium, characterized in that a voltage is applied over time. 2. The method according to claim 1, wherein the image light is divided into R, G, and B channels, and the R, G, and B lights are applied to different areas for image exposure, and at the same time, in each area. An information recording method with adjustable sensitivity using a liquid crystal recording medium, characterized in that the applied voltage / voltage application time is made different. 3. The method according to claim 2, wherein the transmittance of the unexposed portion of the low sensitivity channel of the optical sensor is made higher than that of the high sensitivity channel in accordance with the R, G, B spectral sensitivities of the optical sensor. The information recording method with adjustable sensitivity using a liquid crystal recording medium, characterized in that the applied voltage / voltage application time is set so that 4. The method according to claim 2, wherein the applied voltage / voltage application time is set in accordance with the R, G, and B spectral sensitivities of the optical sensor so as to reduce the sensitivity of the channel with high sensitivity of the optical sensor. An information recording method with adjustable sensitivity using a liquid crystal recording medium. 5. An optical sensor having a photoconductive layer formed on a transparent electrode and a liquid crystal recording medium having a liquid crystal layer in which a liquid crystal is dispersed in a resin are formed on the electrodes so as to oppose each other, and at the same time image exposure is performed. In an information recording apparatus for recording information by applying a voltage between them, at least one electrode of a photosensor or a liquid crystal recording medium is divided into two or more areas, and each area is applied with a different voltage / application time. An information recording apparatus with adjustable sensitivity using a liquid crystal recording medium, characterized in that it is provided with a power supply means for applying voltage. 6. The sensitivity adjustment using a liquid crystal recording medium according to claim 4, further comprising a dividing means for dividing the image light into three surfaces of R, G and B on the front side of the optical sensor. Possible information recording device.