Optical fingerprint imaging system and method with protective film
First Claim
1. An optical fingerprint imaging system for acquiring fingerprint images, the imaging system comprising:
- an optically transparent platen having an exterior surface through which a fingerprint image is to be acquired;
a protective film comprising urethane that is substantially free from imperfections that would affect transmission of light in acquiring a fingerprint image and which is substantially chemically inert to petroleum-based substances with which it may come into contact when receiving a finger to acquire a fingerprint image, the protective film having an outer surface and an inner surface, the inner surface facing the platen, the film adapted to resiliently deform to ridges of a fingerprint from a finger pressed onto the film; and
an adhesive disposed on the inner surface of the protective film for removably attaching the protective film in optical alignment with the platen, the adhesive having a selected cohesive strength such that the protective film may be removed without leaving an adhesive residue thereby allowing repeated replacement of the protective film.
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Accused Products
Abstract
An optical fingerprint imaging system comprises an optically transparent platen and a protective film removably attached to the platen with an adhesive. The protective film protects the platen from scratches, pits, and other surface damage and is substantially chemically inert to petroleum-based substances which may come into contact when receiving a finger pressed to take a fingerprint image. The adhesive has a selected cohesive strength that allows the protective film and adhesive to be removed from the platen without leaving behind an adhesive residue. The protective film can be replaced periodically as part of maintenance of the platen to allow continued acquisition of accurate fingerprint images. A method for protecting a platen is also disclosed.
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Citations
35 Claims
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1. An optical fingerprint imaging system for acquiring fingerprint images, the imaging system comprising:
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an optically transparent platen having an exterior surface through which a fingerprint image is to be acquired; a protective film comprising urethane that is substantially free from imperfections that would affect transmission of light in acquiring a fingerprint image and which is substantially chemically inert to petroleum-based substances with which it may come into contact when receiving a finger to acquire a fingerprint image, the protective film having an outer surface and an inner surface, the inner surface facing the platen, the film adapted to resiliently deform to ridges of a fingerprint from a finger pressed onto the film; and an adhesive disposed on the inner surface of the protective film for removably attaching the protective film in optical alignment with the platen, the adhesive having a selected cohesive strength such that the protective film may be removed without leaving an adhesive residue thereby allowing repeated replacement of the protective film. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A protective film for providing protection to an optically transparent platen of an optical fingerprint imaging device, the platen having an exterior surface through which a fingerprint image is to be acquired, the protective film comprising:
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a urethane that is substantially free from imperfections that would affect transmission of light in acquiring a fingerprint image and which is substantially chemically inert to petroleum—
based substances with which it may come into contact when receiving a finger to acquire a fingerprint image, the urethane providing the protective film with a selected hardness thereby adapting the film to resiliently deform to ridges of a fingerprint from a finger pressed onto the film; andan adhesive disposed on an inner surface of the protective film for removably attaching the protective film in optical alignment with the platen, the inner surface facing the platen, the adhesive having a selected cohesive strength such that the protective film may be removed without leaving an adhesive residue thereby allowing repeated replacement of the protective film. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22)
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23. A method for protecting an optically transparent platen of an optical fingerprint imaging device, the platen having an exterior surface through which a fingerprint image is to be acquired, the method comprising:
- covering the platen with a protective film comprising a urethane that is substantially free from imperfections that would affect transmission of light in acquiring a fingerprint image and which is substantially chemically inert to petroleum-based substances with which it may come into contact when receiving a finger to acquire a fingerprint image, the protective film having an outer surface and an inner surface, the inner surface facing the platen;
removably adhering the protective film to the platen with an adhesive disposed on the inner surface of the protective film for removably attaching the protective film in optical alignment with the platen; resiliently deforming the protective film to ridges of a fingerprint from a finger pressed onto the protective film; and removing the protective film from the platen without leaving any significant adhesive residue on the platen. - View Dependent Claims (24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35)
- covering the platen with a protective film comprising a urethane that is substantially free from imperfections that would affect transmission of light in acquiring a fingerprint image and which is substantially chemically inert to petroleum-based substances with which it may come into contact when receiving a finger to acquire a fingerprint image, the protective film having an outer surface and an inner surface, the inner surface facing the platen;
Specification