METHOD FOR RECORDING A FINGERPRINT IMAGE
A fingerprint image capture system comprises an electro-optical material which captures a static fingerprint image and an apparatus for converting the static fingerprint image into an electronic signal. The image capture system includes an electrode for contacting a finger, and a bias supply for creating an electric field where epidermal ridges contact the electro-optical material. A transistor array senses charge or optical density variations in the electro-optical material to create an electronic representation of the fingerprint image. An initialization electrode places the electro-optical material into a uniform condition prior to acquisition of the fingerprint image. A physical artifact of the fingerprint image can be archived by removing the electro-optical material from the system following the fingerprint image acquisition.
1 . A method for electronically recording a fingerprint image acquired by an electro-optical material, the method comprising:
directing light from an illumination source to a fingerprint image on the electro-optical material; and
capturing an electronic image with a CMOS image sensor module directed to the contact side fingerprint image.
2 . The method of claim 1 wherein the illumination source produces a wavelength invisible to the human eye.
3 . The method of claim 1 wherein the electro-optical material is an electrophoretic material.
4 . The method of claim 1 wherein the illumination source is directed to a contact side fingerprint image.
5 . The method of claim 1 wherein the illumination source is directed to an opposing side fingerprint image.
6 . The method of claim 1 wherein the illumination source is directed to the fingerprint image from at least one side of the fingerprint image.
7 . A method for electronically recording a fingerprint image acquired by an electro-optical material, the method comprising:
directing light from an illumination source through a fingerprint image on the electro-optical material; and
capturing an electronic image with a CMOS image sensor module directed to an opposing side fingerprint image.
8 . The method of claim 7 wherein the illumination source is located on a contact side of the fingerprint image.
9 . The method of claim 7 wherein the illumination source is located on an opposing side of a fingerprint image.
10 . The method of claim 7 wherein the illumination source produces a wavelength invisible to the human eye.
11 . The method of claim 7 wherein the electro-optical material is an electrophoretic material.
12 . A method for electronically recording a fingerprint image acquired by an electro-optical material, the method comprising:
mechanically coupling a free surface of the electro-optical material to a transistor array, the array configured convert illumination incident upon pixels comprising the array into a quantity of electrical charge;
directing light from an illumination source through a contact side fingerprint image on the electro-optical material;
directing emergent illumination from an opposing side fingerprint image onto the transistor array; and
sequentially addressing the transistor array so as to couple the array transistors to charge sensing amplifier circuits.
13 . The method of claim 12 wherein the electro-optical material is an electrophoretic material.
14 . The method of claim 12 wherein the free surface of the electro-optical material is coupled to the transistor array while the fingerprint image is being acquired.
15 . The method of claim 12 wherein the free surface of the electro-optical material is coupled to the transistor array after the fingerprint image has been acquired.
16 . The method of claim 12 wherein the transistor array is a CMOS array fabricated on crystalline silicon.
17 . The method of claim 12 wherein the transistor array is a thin film transistor (TFT) array fabricated on a flexible substrate.
18 . The method of claim 12 wherein the illumination source produces a wavelength invisible to the human eye.