Electronically expiring device
First Claim
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1. A method for expiring a device containing a time cell, the method comprising:
- discharging a stored electrostatic charge in a charge storage element in the time cell, wherein the time cell has a substantially discharged state before a programming operation and has a controlled discharge state after the programming operation, and wherein the time cell transitions after the programming operation from the controlled discharge state to the substantially discharged state within a predetermined time period after the programming operation;
reading a state of the time cell;
generating a signal from the state of the time cell, wherein the signal indicates whether or not the predetermined time period has elapsed since the time cell was programmed; and
in response to the signal indicating that predetermined time period has elapsed, expiring the device.
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Abstract
The present invention relates to a method and system for expiring a device after a predetermined time period has elapsed. A device, which contains its own internal time cell, is designed to stop working or self-destruct after a predetermined time period has expired. The device uses its own time cell so that the elapsed time period is not altered through an external time source. After the predetermined time period has elapsed, the device or a component of the device self-destructs when connected to a power source.
26 Citations
15 Claims
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1. A method for expiring a device containing a time cell, the method comprising:
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discharging a stored electrostatic charge in a charge storage element in the time cell, wherein the time cell has a substantially discharged state before a programming operation and has a controlled discharge state after the programming operation, and wherein the time cell transitions after the programming operation from the controlled discharge state to the substantially discharged state within a predetermined time period after the programming operation;
reading a state of the time cell;
generating a signal from the state of the time cell, wherein the signal indicates whether or not the predetermined time period has elapsed since the time cell was programmed; and
in response to the signal indicating that predetermined time period has elapsed, expiring the device. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A system for expiring a device containing a time cell, the system comprising:
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discharging means for discharging a stored electrostatic charge in a charge storage element in the time cell, wherein the time cell has a substantially discharged state before a programming operation and has a controlled discharge state after the programming operation, and wherein the time cell transitions after the programming operation from the controlled discharge state to the substantially discharged state within a predetermined time period after the programming operation;
reading means for reading a state of the time cell;
generating means for generating a signal from the state of the time cell, wherein the signal indicates whether or not the predetermined time period has elapsed since the time cell was programmed; and
in response to the signal indicating that predetermined time period has elapsed, expiring means for expiring the device.
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11. A self-expiring device comprising:
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a time cell, wherein discharge of a stored charge within the time cell causes operating characteristics of at least one component within the time cell to vary in a controlled fashion with the passage of time, such that the time cell becomes capable of producing a time-expiration signal after a predetermined time period has elapsed;
at least one additional circuit component that is required for proper operation of the device; and
disabling circuitry, wherein the disabling circuitry responds to the time cells producing an expiration signal by disabling the at least one additional circuit component. - View Dependent Claims (12, 13, 14, 15)
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Specification