Photo-addressable type recording display apparatus

• US 20020005827A1
• Filed: 06/12/2001
• Published: 01/17/2002
• Est. Priority Date: 06/13/2000
• Status: Active Grant

• Current Assignee: Fuji Xerox Company Limited (Xerox Holdings Corp.)
• Original Assignee: Fuji Xerox Company Limited (Xerox Holdings Corp.)
• Inventors: Kobayashi, Hideo
• Granted Patent: US 6,774,880 B2
• Time in Patent Office: Days
• US Class Current: 345/87
• CPC Class Codes: G02F 1/1334 based on polymer dispersed liquid crystals, e.g. microencapsulated liquid crystals
• CPC Class Codes: G02F 1/135 Liquid crystal cells structurally associated with a photoconducting or a ferro-electric layer, the properties of which can be optically or electrically varied G02F1/133348 takes precedence
• CPC Class Codes: G02F 1/13718 based on a change of the texture state of a cholesteric liquid crystal
• CPC Class Codes: G02F 1/141 using ferroelectric liquid crystals
• CPC Class Codes: G09G 3/02 by tracing or scanning a light beam on a screen

Abstract

A photo-addressable type recording display apparatus realizes high sensitivity recording display and realizes recording display with short writing pulse application time. The photo-addressable type recording display apparatus is provided with a recording unit that displays an image, a light writing unit that writes an image in the recording unit by the pattern of light, and a control unit that controls the recording unit and the light writing unit. The recording unit is provided with a spatial light modulation element and a driving unit, and the spatial light modulation element has a memory liquid crystal display element layer and organic photoconductive switching element layer. The control unit determines the magnitude and the application time of a voltage that is applied on the spatial light modulation element by the driving unit so that the threshold voltage corresponds to the voltage waveform determined correspondingly to the comparative magnitude relation between the time constant D of the liquid crystal display element layer and the time constant S of the organic photoconductive switching element layer during non-irradiation with light and irradiation with light by the light writing unit, and supplies a trigger signal for driving waveform output to the driving unit.

Claims

1. A photo-addressable type recording display apparatus comprising:

a photo-addressable type recording display medium provided with a memory display element layer having a predetermined impedance and a light switching element layer having an impedance that is variable depending on irradiation with light laminated on the display element layer and electrically connected in series to the display element layer;

a pattern light irradiation source that irradiates the photo-addressable type recording display medium with a pattern light that has been converted corresponding to image information;

a pulse voltage application part that applies a predetermined pulse voltage to the photo-addressable type recording display medium; and

a driving control part that controls the pulse voltage applied by the pulse voltage application part in accordance with a result of comparison between the predetermined impedance of the display element layer and the impedance of the light switching element layer varied depending on the quantity of light from the pattern light irradiation source for controlling a pulse waveform and a voltage amplitude of the voltage applied to the display element layer, thereby controlling the display state of the photo-addressable type recording display medium.

2. The photo-addressable type recording display apparatus as claimed in claim 1, wherein the result of comparison between the impedance of the display element layer and the impedance of the light switching element layer is varied by controlling a time constant of at least one of the display element layer and the light switching element layer.

3. The photo-addressable type recording display apparatus as claimed in claim 2, wherein the light switching element layer is formed of photoconductive material, and the driving control part controls the quantity of light from the pattern light irradiation source and thereby controls the quantity of charge generated in the light switching element layer corresponding to the light quantity to thereby change a resistance component of the switching element layer, and resultantly controls the time constant.

4. The photo-addressable type recording display apparatus as claimed in claim 2, wherein

the photo-addressable type recording display medium has a time constant of the light switching element layer that is extremely larger than a time constant of the display element layer during non-irradiation with light, and a time constant of the light switching element layer is approximately equal to or smaller than a time constant of the display element layer during irradiation with light, and

the driving control part controls the voltage applied to the photo-addressable type recording display medium so that an applied voltage equal to or higher than a threshold value is applied to the display element layer for a duration that is sufficiently long to change the phase of the display element layer during non-irradiation with light, and so that the voltage of the display element layer is suppressed to a value lower than the threshold value, or the voltage of the display element layer is suppressed to a value equal to or lower than the threshold voltage due to the waveform transformation during irradiation with light.

5. The photo-addressable type recording display apparatus as claimed in claim 2, wherein

the photo-addressable type recording display medium has a time constant of the light switching element layer that is larger than a time constant of the display element layer during non-irradiation with light, and the time constant of the light switching element layer is approximately equal to or smaller than the time constant of the display element layer during irradiation with light, and

the driving control part controls the voltage applied to the photo-addressable type recording display medium so that a voltage higher than a threshold voltage having an amplitude that is sufficiently long to change the phase is being always applied to the display element layer, and so that a voltage equal to or higher than the threshold value is applied to the display element layer for a duration that is sufficiently long to change the phase during irradiation with light and a voltage having a voltage amplitude and duration of application that are necessary for the display element layer to be turned off by a voltage drop from an amplitude equal to or lower than the threshold value to a voltage being turned off is applied during non-irradiation with light.

6. The photo-addressable type recording display apparatus as claimed in claim 2, wherein

the photo-addressable type recording display medium has a time constant of the light switching element layer that is approximately equal to a time constant of the display element layer during non-irradiation with light, and the time constant of the light switching element layer is smaller than the time constant of the display element layer during irradiation with light, and

the driving control part controls the voltage applied to the photo-addressable type recording display medium so that a voltage equal to or higher than a threshold value is applied to the display element layer for a duration that is sufficiently long to change the phase during non-irradiation with light, and so that a voltage having an amplitude effectively equal to or lower than the threshold voltage is applied to the display element layer due to the waveform transformation during irradiation with light.

7. The photo-addressable type recording display apparatus as claimed in claim 2, wherein

the photo-addressable type recording display medium has a time constant of the light switching element layer that is approximately equal to a time constant of the display element layer during non-irradiation with light, and the time constant of the light switching element layer is smaller than the time constant of the display element layer during irradiation with light, and

the driving control part controls the voltage applied to the photo-addressable type recording display medium so that a voltage equal to or lower than a threshold voltage is applied to the display element layer during non-irradiation with light, and so that a voltage equal to or higher than the threshold value is applied to the display element layer for a duration that is sufficiently long to change the phase of the display element layer during irradiation with light.

8. The photo-addressable type recording display apparatus as claimed in claim 2, wherein

the photo-addressable type recording display medium has a time constant of the light switching element layer that is larger than a time constant of the display element layer both during non-irradiation with light and during irradiation with light, and

the driving control part controls the voltage applied to the photo-addressable type recording display medium so that a voltage is applied to the display element layer for a duration that is shorter than a duration to change the phase of the display element layer or a voltage smaller than the threshold value is applied to the display element layer during non-irradiation with light, and controls so that a voltage equal to or higher than the threshold value is applied to the display element layer for a duration that is sufficiently long to change the phase of the display element layer during irradiation with light.

9. The photo-addressable type recording display apparatus as claimed in claim 2, wherein

the photo-addressable type recording display medium has a time constant of the display element layer that is larger than a time constant of the light switching element layer during both non-irradiation with light and irradiation with light, and

the driving control part controls an amplitude and application duration of the voltage applied to the photo-addressable type recording display medium so that the display of the display element layer is turned off by the voltage drop from an amplitude equal to or lower than a threshold value to a voltage being turned off during non-irradiation with light, and so that a voltage equal to or higher than the threshold value is applied to the display element layer for a duration that is sufficiently long to change the phase of the display element layer during irradiation with light.

10. The photo-addressable type recording display apparatus as claimed in claim 2, wherein

the photo-addressable type recording display medium has a time constant of the light switching element layer that is smaller than the time constant of the display element layer during both non-irradiation with light and irradiation with light, and

the driving control part controls the voltage applied to the photo-addressable type recording display medium so that a voltage is applied to the display element layer for a duration that is shorter than a duration to change the phase of the display element layer or a voltage smaller than a threshold value is applied to the display element layer during non-irradiation with light, and so that a voltage equal to or higher than the threshold value is applied to the display element layer during irradiation with light.

11. The photo-addressable type recording display apparatus as claimed in claim 2, wherein

the photo-addressable type recording display medium has a time constant of the display element layer that is smaller than a time constant of the light switching element layer during both non-irradiation with light and irradiation with light, and

the driving control part controls the voltage applied to the photo-addressable type recording display medium so that a voltage equal to or higher than a threshold value that is sufficiently high to change the phase of the display element layer is applied to the display element layer during non-irradiation with light, and so that a voltage having an amplitude equal to or lower than the threshold voltage is applied to the display element layer due to the waveform transformation caused after the voltage is turned off during irradiation with light.

12. The photo-addressable type recording display apparatus as claimed in claim 2, wherein

the photo-addressable type recording display medium has a time constant of the light switching element layer that is larger than a time constant of the display element layer during non-irradiation with light, and the time constant of the light switching element layer is smaller than the time constant of the display element layer during irradiation with light, and

the driving control part controls the voltage applied to the photo-addressable type recording display medium so that a voltage equal to or higher than a threshold value is applied to the display element layer for a duration that is sufficiently long to change the phase of the display element layer during both non-irradiation with light and irradiation with light, and so that a voltage having an amplitude effectively equal to or lower than the threshold voltage is applied to the display element layer due to the waveform transformation caused after the voltage drops to an amplitude equal to or lower than the threshold value during irradiation with light.

13. The photo-addressable type recording display apparatus as claimed in claim 2, wherein

the photo-addressable type recording display medium has a time constant of the light switching element layer that is larger than a time constant of the display element layer during non-irradiation with light, and the time constant of the light switching element layer is smaller than the time constant of the display element layer during irradiation with light, and

the driving control part controls the voltage applied to the photo-addressable type recording display medium so that a voltage is applied to the display element layer for a duration that is shorter than a duration to change the phase of the display element layer or a voltage smaller than a threshold value is applied to the display element layer during non-irradiation with light, and so that a voltage equal to or higher than the threshold value is applied to the display element layer during irradiation with light.

14. The photo-addressable type recording display apparatus as claimed in claim 2, wherein

the photo-addressable type recording display medium has a time constant of the light switching element layer that is larger than a time constant of the display element layer during non-irradiation with light, and the time constant of the light switching element layer is smaller than the time constant of the display element layer during irradiation with light, and

the driving control part controls the voltage applied to the photo-addressable type recording display medium so that a voltage equal to or higher than the threshold value is applied to the display element layer for a duration that is sufficiently long to change the phase of the display element layer by overshooting caused while the voltage is being turned off during non-irradiation with light, and so that a voltage arising from overshooting caused while the voltage is being turned off, the voltage being lower than the voltage necessary to change the phase of the display element layer, or so that a voltage is applied to the display element layer for a duration that is shorter than a duration to change the phase during irradiation with light.

15. The photo-addressable type recording display apparatus as claimed in claim 2, wherein

the photo-addressable type recording medium comprises a display element layer having a first threshold value at which the display is turned off and a second threshold value at which the display is turned on when a voltage equal to or higher than the first threshold value is applied, and has a time constant of the light switching element layer that is larger than a time constant of the display element layer during non-irradiation with light, and the time constant of the light switching element layer is smaller than the time constant of the display element layer during irradiation with light, and

the driving control part controls the voltage applied to the photo-addressable type recording display medium so that a voltage arising from overshooting caused while the voltage is being turned off is applied to the display element layer during non-irradiation with light, the voltage being equal to or higher than the first threshold value and equal to or lower than the second threshold value, and so that a voltage equal to or higher than the second threshold value is applied to the display element layer during irradiation with light.

16. The photo-addressable type recording display apparatus as claimed in claim 1, wherein the display element layer comprises any one of a polymer network stabilized liquid crystal element, polymer dispersion liquid crystal element, and capsulated liquid crystal element that are formed of cholesteric liquid crystal.

17. The photo-addressable type recording display apparatus as claimed in claim 1, wherein the switching element layer is formed of organic photoconductive material.