Optical storage media having limited useful life
First Claim
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1. A data storage medium, comprising:
- a substrate supporting a data storage region for storing readable data, and being subjected in normal use to be to motion when read;
a reservoir attached to the substrate and located in proximity to the data storage region for storing a flowable chemical agent and so arranged that the said chemical agent can flow from the reservoir to interact with the data storage medium and permanently interfere with the readability of the data;
wherein the chemical agent is retained in the reservoir substantially solely by liquid surface phenomena, and wherein in normal use force associated with the motion tends to overcome the action of the liquid surface phenomena and cause the chemical agent to flow from the reservoir.
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Abstract
An optical disc or other data storage medium has a substrate supporting a data storage region for storing readable data, and is caused to spin or is otherwise subjected to motion when read. A reservoir attached to the substrate and located in proximity to the data storage region stores a liquid reagent by liquid surface phenomena. When the medium is moved in order to read it, the centrifugal or other force causes the reagent to flow from the reservoir to interact with the data storage medium and interfere with the readability of the data.
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Citations
27 Claims
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1. A data storage medium, comprising:
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a substrate supporting a data storage region for storing readable data, and being subjected in normal use to be to motion when read;
a reservoir attached to the substrate and located in proximity to the data storage region for storing a flowable chemical agent and so arranged that the said chemical agent can flow from the reservoir to interact with the data storage medium and permanently interfere with the readability of the data;
wherein the chemical agent is retained in the reservoir substantially solely by liquid surface phenomena, and wherein in normal use force associated with the motion tends to overcome the action of the liquid surface phenomena and cause the chemical agent to flow from the reservoir. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A data storage medium rotated about an axis in use and comprising:
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a data storage region;
an elongate reservoir forming a circular curve centered on the axis; and
a chemical agent capable of interacting with the data storage region and permanently reducing the readability of the data;
wherein the chemical agent is stored in the elongate reservoir, and is arranged to be released from the reservoir by centrifugal force to interact with the data storage region when the medium is rotated in use. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. An optical disc, comprising:
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a reflective layer from which data may be read; and
a reservoir for a liquid reagent that can alter the properties of the reflective layer to interfere with reading of the data;
wherein the reservoir is radially inward of the data on the reflective layer;
wherein the liquid is retained in the reservoir substantially by liquid surface phenomena; and
wherein centrifugal force in normal reading of the disc is sufficient to overcome the surface phenomena and cause radially outward flow of the liquid to interact with the reflective layer. - View Dependent Claims (24, 25, 26, 27)
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Specification