Fingerprint imaging device including an optical plate having microreflectors
First Claim
1. A device for creating an image of a fingerprint pattern on an image sensor, the device comprising:
- an optical plate including;
a finger field to which a finger is pressed to create the fingerprint pattern, andan array of microreflectors covering part of the optical plate, the microreflectors being distributed along a base surface;
an illuminating tool that illuminates the finger field to create imaging light rays relating to the fingerprint pattern; and
an imaging lens to receive the imaging light rays reflected from the array of microreflectors to create the fingerprint pattern image at a location external to the optical plate, the imaging lens including an aperture stop that defines an aperture light beam of the reflected imaging light rays forming the image of the fingerprint pattern;
in which the microreflectors are inclined to the base surface so that an area of a projection of the microreflectors on the base surface taken along a path of the imaging light rays reflected at the surface of the microreflectors and passing through the aperture stop exceeds an area of a projection of the microreflectors on the base surface taken along a path of the reflected imaging light rays incident to the surface of the microreflectors.
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Accused Products
Abstract
A compact-sized fingerprint imaging device includes an optical plate for creating a fingerprint pattern at a finger field on the optical plate. The fingerprint pattern is illuminated with light from an illuminating tool to create imaging light rays. A small thickness of the optical plate, and hence of the fingerprint imaging device, is possible due to a design that includes an array of microreflectors covering a part of the optical plate, the microreflectors being distributed along a base surface. The imaging light rays from the fingerprint pattern that are reflected by the array of microreflectors are received by an imaging lens that projects an image of the fingerprint pattern to an image sensor.
109 Citations
21 Claims
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1. A device for creating an image of a fingerprint pattern on an image sensor, the device comprising:
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an optical plate including; a finger field to which a finger is pressed to create the fingerprint pattern, and an array of microreflectors covering part of the optical plate, the microreflectors being distributed along a base surface; an illuminating tool that illuminates the finger field to create imaging light rays relating to the fingerprint pattern; and an imaging lens to receive the imaging light rays reflected from the array of microreflectors to create the fingerprint pattern image at a location external to the optical plate, the imaging lens including an aperture stop that defines an aperture light beam of the reflected imaging light rays forming the image of the fingerprint pattern; in which the microreflectors are inclined to the base surface so that an area of a projection of the microreflectors on the base surface taken along a path of the imaging light rays reflected at the surface of the microreflectors and passing through the aperture stop exceeds an area of a projection of the microreflectors on the base surface taken along a path of the reflected imaging light rays incident to the surface of the microreflectors. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. An electronic apparatus comprising:
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a device to create an image of a fingerprint pattern on an image sensor, the device comprising; an optical plate including; a finger field to which a finger is pressed to create the fingerprint pattern, and an array of microreflectors covering part of the optical plate, the microreflectors being distributed along a base surface; an illuminating tool that illuminates the finger field to create imaging light rays relating to the fingerprint pattern; an imaging lens to receive the imaging light rays reflected from the array of microreflectors to create the fingerprint pattern image at a location external to the optical plate, the imaging lens including an aperture stop that defines an aperture light beam of the reflected imaging light rays forming the image of the fingerprint pattern; in which the microreflectors are inclined to the base surface so that an area of a projection of the microreflectors on the base surface taken along a path of the reflected imaging light rays and passing through the center of the aperture stop exceeds an area of a projection of the microreflectors on the base surface taken along a path of the imaging light rays incident to the surface of the microreflectors; and a housing shaped to hold electronic components for operation of the electronic apparatus and shaped to retain the device, the housing including an outer surface; in which the finger field lies flush with the outer surface of the housing when the device is retained by the housing. - View Dependent Claims (16, 17)
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18. A device for creating an image of a fingerprint pattern on an image sensor, the device comprising:
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an optical plate including; a finger field to which a finger is pressed to create the fingerprint pattern, and an array of microreflectors covering part of the optical plate, the microreflectors being distributed along a base surface; an illuminating tool that illuminates the finger field to create imaging light rays relating to the fingerprint pattern; and an imaging lens to receive the imaging light rays reflected from the array of microreflectors to create the fingerprint pattern image at a location external to the optical plate, the imaging lens including an aperture stop that defines an aperture light beam of the reflected imaging light rays forming the image of the fingerprint pattern; in which the microreflectors are inclined to the base surface so that an angle between the normal to the base surface and an imaging light ray incident to a microreflector is less than an angle between the normal to the base surface and that imaging light ray reflected from the microreflector.
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19. A device for creating an image of a fingerprint pattern on an image sensor, the device comprising:
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an optical plate including; a finger field to which a finger is pressed to create the fingerprint pattern, and an array of microreflectors covering part of the optical plate, the microreflectors being distributed along a base surface and being shaped like V-shaped grooves; an illuminating tool that illuminates the finger field to create imaging light rays relating to the fingerprint pattern; and an imaging lens to receive the imaging light rays reflected from the array of microreflectors to create the fingerprint pattern image at a location external to the optical plate, the imaging lens including an aperture stop that defines an aperture light beam of the reflected imaging light rays forming the image of the fingerprint pattern; wherein the side of the grooves facing the imaging lens receives and reflects the imaging light rays that define the aperture light beam.
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20. An electronic apparatus comprising:
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a device for creating an image of a fingerprint pattern on an image sensor, the device comprising; an optical plate including; a finger field to which a finger is pressed to create the fingerprint pattern, and an array of microreflectors covering part of the optical plate, the microreflectors being distributed along a base surface; an illuminating tool that illuminates the finger field to create imaging light rays relating to the fingerprint pattern; an imaging lens to receive the imaging light rays reflected from the array of microreflectors to create the fingerprint pattern image at a location external to the optical plate, the imaging lens including an aperture stop that defines an aperture light beam of the reflected imaging light rays forming the image of the fingerprint pattern; in which the microreflectors are inclined to the base surface so that an area of a projection of the microreflectors on the base surface taken along a path of the reflected imaging light rays and passing through the aperture stop exceeds an area of a projection of the microreflectors on the base surface taken along a path of the imaging light rays incident to the surface of the microreflectors; and a housing shaped to hold electronic components for operation of the electronic apparatus and shaped to retain the device; in which the optical plate operates simultaneously as an indicator surface of the housing and as a finger field.
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21. A device for creating an image of a fingerprint pattern on an image sensor, the device comprising:
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an optical plate including; a finger field to which a finger is pressed to create the fingerprint pattern, an array of microreflectors covering part of the optical plate, the microreflectors being distributed along a base surface, an illuminating tool that illuminates the finger field to create imaging light rays relating to the fingerprint pattern; and an imaging lens receiving the imaging light rays reflected from the array of microreflectors to create the fingerprint pattern image at a location external to the optical plate, the imaging lens including an aperture stop that defines an aperture light beam of the reflected imaging light rays forming the image of the fingerprint pattern; in which the microreflectors are inclined to the base surface so that a cross-section of image light rays incident to the microreflectors is discontinuously greater than a cross-section of the imaging light rays reflected from the microreflector.
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Specification