Printed matter – Having revealable concealed information – fraud preventer or... – Utilizing chemical
Reexamination Certificate
2000-06-06
2001-11-20
Fridie, Jr., Willmon (Department: 3722)
Printed matter
Having revealable concealed information, fraud preventer or...
Utilizing chemical
C283S017000, C283S070000, C283S072000, C283S096000, C283S097000, C283S098000, C283S901000, C283S903000, C040S406000, C040S407000, C040S615000, C040S675000, C116S206000, C428S321100, C428S321500, C428S916000
Reexamination Certificate
active
06318760
ABSTRACT:
TECHNICAL FIELD
When activated, irreversible displays undergo permanent changes in appearance. Initially obscured or otherwise hidden information is revealed by the changes of appearance.
BACKGROUND
Changes that take place in irreversible displays generally involve the revelation of indicia, which can range from a patch of color to text and pictures. The indicia can be revealed by chemical or physical agents that change themselves or that produce other changes in the displays. For example, opaque coloring agents can be rendered transparent to reveal underlying indicia, or similar agents can change from one color to another to indicate a change.
Chemical transformations in irreversible displays are sometimes used for security purposes to provide evidence of tampering or counterfeiting. U.S. Pat. No. 4,488,646 to McCorkle hides a warning message behind a solvent-sensitive blush coating to provide evidence of solvent tampering with letters, tickets, and other information-bearing constructions. Upon exposure to a wide range of aromatic or aliphatic solvents, the blush coating is transformed into a transparent state revealing the message. U.S. Pat. No. 4,903,991 to Wright discloses a document security system in which a latent image is developed by rupturing photoactive microcapsules to verify authenticity.
Mechanical transformations are more often used for interactive game pieces. The most common are scratch-off games in which an opaque coating is removed by abrasion to reveal a hidden indicium. Chang et al. in U.S. Pat. No. 5,431,452 separately position a latent image and a removable image-developing device on different portions of a substrate. The image-developing device contains a chromogenic composition that converts the latent image into a visible image.
Commonly assigned U.S. application Ser. No. 09/426,225 entitled “Irreversible Thin Film Display with Clearing Agent”, which is hereby incorporated by reference, exploits features of thin metal films for temporarily obscuring indicia from view. Chemical clearing agents clear the metal films to display the indicia. The thin metal films can be cleared to reveal underlying indicia or the indicia can be formed by clearing the metal films in predetermined patterns.
SUMMARY OF INVENTION
We have enhanced performance capabilities and expanded performance options of our irreversible thin metal displays activated by chemical clearing agents. Our new displays include capabilities for producing dynamic imaging effects such as forming temporary or evolving images by controlling rates at which different portions of the metal films are cleared. For example, the differential clearing rates can be used to form a temporary image in the metal film, which eventually clears to reveal a more permanent underlying image.
An exemplary irreversible multistage display includes a metal layer having first and second portions. A first graphics layer underlies both portions of the metal layer. A second graphics layer is laid out in a pattern on the first portion of the metal layer. Preferably, neither graphics layer is apparent at first. The two portions of the metal layer are differentially accessible to a chemical clearing agent that produces a chemical reaction for clearing the metal layer. As a result, the first and second portions of the metal layer clear at different rates temporarily displaying the pattern of the second graphics layer in the metal layer in advance of more permanently displaying the underlying first graphics layer.
Part of the more permanent image (i.e., the first graphics layer) made visible by clearing the second portion of the metal layer preferably provides contrast for viewing the temporary image (i.e., the pattern of the second graphics layer) in the first portion of the metal layer. The second graphics layer is preferably laid out using a material that influences the relative rates at which the first and second portions of the metal layer are cleared. For example, bonding characteristics of the second graphics layer to the metal layer can be adjusted to delay access of the clearing agent to the metal layer. Inks formulated to partially bond with the metal layer are particularly suitable for this purpose.
An exemplary irreversible display system for producing a temporary display of information includes both a metal layer and a chemical clearing agent, which are initially maintained out of operative contact with each other within a display region. A pattern formed on the metal layer within the display region encodes the information. Moving the clearing agent and the metal layer into operative contact with each other initiates a chemical reaction for clearing the metal layer. The pattern is composed of a buffer material that delays clearing of the patterned portion of the metal layer to temporarily display the encoded information.
Preferably, the buffer material is printed on the metal layer and contains an anti-bonding agent that reduces adherence of the buffer material to the metal layer. Additional patterns that delay clearing by different amounts can be formed on the metal layer to display an evolving message or a succession of different messages. More delay can be achieved by increasing the bonding strength of the buffer materials to the metal layer.
The desired buffer materials can be arranged for encoding information or for controlling the manner in which underlying images are revealed. For example, the buffer materials can regulate clearing of the metal layer from outside-in, side-to-side, or top-to-bottom or through a speckle pattern to enhance interest in the underlying image. Temporary block-out patterns can also be formed on the metal layer to deny viewing access to the underlying images before the metal film is cleared. Alternatively, the desired buffer material can be applied as a continuous coating to regulate access of the chemical clearing agent to the metal layer. For example, a continuous coating of the buffer material can be used to protect that metal layer from unintended environmental influences or to provide a temporary barrier to the chemical clearing agent.
The metal layer is preferably composed of a metal, such as zinc, silver, or aluminum that is sputtered or vapor deposited onto a clear film. The clearing agent can be drawn from a variety of materials including electrolytes, acids, bases, and other agents that participate in localized reactions for corroding or otherwise clearing the metal layer. Among the choices are many safe and environmentally friendly materials including edibles such as juices, carbonated beverages, and even condiments.
The preferred reactions that clear the metal layer are localized electrochemical reactions that oxidize the metal layer. In contrast to galvanic or electrolytic electrochemical reactions, the localized electrochemical reactions between the clearing agent and the metal layer produce a mixed electropotential and do not require a net flow of current through the metal layer. However, displays with metal layers cleared by galvanic or electrolytic reactions could also benefit from the invention.
Our irreversible displays can be manufactured by an in-line press. All of the layers including substrates, metal films, clearing agents, graphics, adhesives, and spacers can be formed from individual webs or from layers applied to the individual webs. The result is a succession of thin flexible displays that can be manufactured quickly at low cost and integrated if desired with other press-produced or otherwise compatible articles.
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patent: 5431452 (1
Good David M.
Mitchell, Jr. Chauncey T.
Shadle Mark A.
Eugene Stephens & Associates
Fridie Jr. Willmon
Henderson Mark T.
Ryan Thomas B.
Timer Technologies, LLC
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