Portable information record medium having liquid crystal and photoconductive layers

• US 5,055,662 A
• Filed: 07/28/1989
• Issued: 10/08/1991
• Est. Priority Date: 08/31/1988
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Hasegawa, Haruyoshi
• Primary Examiner(s): Levy, Stuart S.
• Assistant Examiner(s): DuBois, Steven M.
• Application Number:
  US07/386,263
• Time in Patent Office: 802 Days
• Field of Search: 235/380, 235/487, 235/492, 365/108, 365/107
• US Class Current: 235/492
• 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: G06K 1/126 by photographic or thermographic registration recording apparatus for measuring instruments G01D15/00
• CPC Class Codes: G06K 19/08 using markings of different kinds or more than one marking of the same kind in the same record carrier, e.g. one marking being sensed by optical and the other by magnetic means
• CPC Class Codes: G06Q 20/3437 the counter having non-monetary units, e.g. trips
• CPC Class Codes: G07F 7/02 by keys or other credit registering devices

Abstract

A portable prepaid card is disclosed comprising a substrate on which a photoconductive layer, a liquid crystal layer, and a transparent electrode plate are built up in this order. When an optical image is radiated on the photoconductive layer through the liquid crystal layer, the exposed regions and the unexposed regions of the photoconductive layer have different volume resistances. In this state, if a predetermined voltage is applied from the outside between the electrode plate and the photoconductive layer, a visible image corresponding to the radiated optical image is fixed in the liquid crystal layer.

Claims

1. A portable information record medium for displaying a visible image in accordance with an optical image radiated on the medium from outside, the medium comprising:

a portable substrate;

image holding means, provided on the substrate, for holding information in the form of a visible image, said image holding means including a liquid crystal layer having liquid crystal molecules whose orientation change in response to an applied voltage; and

image forming means, provided between the image holding means and the substrate, for forming a visible image, corresponding to a radiated optical image, in the image holding means, the image forming means including a photoconductive layer having an electrical resistance variable in accordance with the radiated optical image, a part of the photoconductive layer, which has been exposed to light, having an electrical resistance different from that of other parts of the photoconductive layer such that an exposed part of the liquid crystal layer, which is opposite the light-exposed part of the photoconductive layer, is subject to a voltage different from a voltage applied to other parts of the liquid crystal layer.

2. A record medium according to claim 1, further comprising contacts through which voltage is applied between a transparent electrode plate and the photoconductive layer.

3. A record medium according to claim 1, wherein the liquid crystal layer includes a mixed memory/phase-transition liquid crystal.

4. A record medium according to claim 1, further comprising a transparent electrode plate which includes a high-molecular-weight polymer film and an oxide film formed on the high-molecular-weight polymer film.

5. A record medium according to claim 1, wherein the liquid crystal layer comprises first and second display regions to which voltage can be applied mutually independently.

6. A record medium according to claim 1, further comprising recording means, provided on the substrate, for recording information in the form of machine-readable signals.

7. A record medium according to claim 6, wherein the recording means comprises a recording section for recording the information magnetically.

8. A record medium according to claim 7, wherein the recording section comprises a magnetic stripe on the substrate.

9. A record medium according to claim 6, wherein the recording means comprises a recording section for recording the information electrically.

10. A record medium according to claim 9, wherein the recording section comprises an integrated circuit provided on the substrate.

11. A portable information record medium comprising:

a portable substrate;

a liquid crystal layer provided on the substrate to hold information in the form of a visible image, the liquid crystal layer having liquid crystal molecules whose orientation changes in response to an applied voltage;

image forming means, including a photoconductive layer between the substrate and the liquid crystal layer, and a transparent electrode plate provided on the liquid crystal layer, for erasing a first image held in the liquid crystal layer and for forming a second image in the liquid crystal layer by changing voltage applied to the liquid crystal layer in response to an external signal, the photoconductive layer having electrical resistance varying in accordance with a radiated optical image, a part of the photoconductive layer, which has been exposed to light, having an electrical resistance different from that of other parts of the photoconductive layer such that an exposed part of the liquid crystal layer, which is opposite the light-exposed part of the photoconductive layer, is subject to a voltage different from a voltage applied to other parts of the liquid crystal layer; and

recording means, provided on the substrate, for recording the information in the form of machine-readable signals.

12. A portable information record medium for displaying a visible image in accordance with an optical image radiated on the medium from outside, the medium comprising:

a portable substrate having an electrode;

image holding means, provided on the substrate, for holding information on a state of use of the medium in the form of a visible image, said image holding means including a liquid crystal layer having liquid crystal molecules whose orientation changes in response to an applied voltage; and

voltage applying means, provided on the substrate, for applying voltage to the liquid crystal layer to erase a first image held in the image holding means and to form a second image in the image holding means in response to an external signal, said voltage applying means including a transparent electrode plate provided on the liquid crystal layer, voltage being applied between the electrode and the transparent electrode plate, and a photoconductive layer arranged between the liquid crystal layer and the substrate and having an electrical resistance variable in accordance with a radiated optical image, a part of the photoconductive layer, which has been exposed to light, having an electrical resistance different from that of other parts of the photoconductive layer such that an exposed part of the liquid crystal layer, which is opposite the light-exposed part of the photoconductive layer, is subject to a voltage different from a voltage applied to other parts of the liquid crystal layer.