Optical fingerprint sensor with enhanced anti-counterfeiting features
An image sensing apparatus is disclosed. The image sensing apparatus includes a pixel array and micro lenses disposed above the pixel array. The pixel array includes sensing pixels configured to capture minutia points of a fingerprint and positioning pixels configured to provide positioning codes.
1. An image sensing apparatus, comprising:
a pixel array, the pixel array comprising:
a plurality of sensing pixels configured to capture minutia points of a fingerprint; and
a plurality of positioning pixels configured to provide vectors from the minutia points to the positioning pixels for anti-counterfeiting identification; and
a plurality of micro lenses disposed above the pixel array.
2. The image sensing apparatus of claim 1 , wherein all the sensing pixels are grayscale pixels.
3. The image sensing apparatus of claim 1 , wherein all the sensing pixels are color pixels.
4. The image sensing apparatus of claim 1 , wherein the sensing pixels include a plurality of grayscale pixels and a plurality of color pixels.
5. The image sensing apparatus of claim 4 , wherein the color pixels are positioned adjacent to the positioning pixels.
6. The image sensing apparatus of claim 5 , wherein the color pixels and the adjacent positioning pixels are arranged in the same pattern.
7. The image sensing apparatus of claim 1 , wherein the positioning pixels are arranged in a repeated pattern in the pixel array.
8. The image sensing apparatus of claim 1 , wherein the positioning pixels are distributed randomly in the pixel array.
9. The image sensing apparatus of claim 1 , further comprising:
a collimator above the micro lenses; and
an illumination layer above the collimator.
10. The image sensing apparatus of claim 1 , wherein the micro lenses are disposed directly above the sensing pixels but not above the positioning pixels.
11. An optical fingerprint sensor, comprising:
an array of light filters arranged in columns and rows;
an array of light receiving elements under the array of light filters, wherein the array of light receiving element is configured to convert incident light reflected from a fingerprint to a fingerprint image; and
a plurality of opaque films disposed above a portion of the light receiving elements, wherein the portion of the light receiving elements is configured to add dark pixels to the fingerprint image as positioning codes.
12. The optical fingerprint sensor of claim 11 , wherein the opaque films are made of metal.
13. The optical fingerprint sensor of claim 11 , wherein the opaque films are disposed between the array of light filters and the array of light receiving elements.
14. The optical fingerprint sensor of claim 11 , wherein locations of the portion of the light receiving elements form a regular pattern.
15. The optical fingerprint sensor of claim 14 , wherein inside the regular pattern, the portion of the light receiving elements form at least two different sub patterns.
16. The optical fingerprint sensor of claim 11 , wherein locations of the portion of the light receiving elements are distributed randomly.
17. The optical fingerprint sensor of claim 11 , wherein the array of light filters includes a combination of color filters and transparent filters.
18. An image sensing apparatus, comprising:
a pixel array, the pixel array comprising:
a plurality of sensing pixels configured to convert incident light reflected from a fingerprint to a fingerprint image;
a plurality of positioning pixels, wherein the plurality of sensing pixels and the plurality of positioning pixels are blended in the pixel array; and
a plurality of opaque films disposed above the plurality of positioning pixels, such that the plurality of positioning pixels are configured to add dark pixels to the fingerprint image as positioning codes; and
a plurality of micro lenses disposed above the pixel array.
19. The image sensing apparatus of claim 18 , wherein the sensing pixels include a plurality of grayscale pixels and a plurality of color pixels.
20. The image sensing apparatus of claim 19 , wherein the color pixels are positioned next to the positioning pixels.