Optical sensor for integration over a display backplane
Systems and methods for optical imaging are disclosed. An optical sensor for imaging a biometric input object on a sensing region includes a transparent layer having a first side and a second side opposite the first side; a set of apertures disposed above the first side of the transparent layer; a first set of reflective surfaces disposed below the second side of the transparent layer configured to receive light transmitted through the first set of apertures and to reflect the received light; a second set of reflective surfaces disposed above the first side of the transparent layer configured to receive the light reflected from the first set of reflective surfaces and to further reflect the light; and a plurality of detector elements positioned to receive the further reflected light from the second set of reflective surfaces.
1. A sensor assembly for integration in a display, comprising:
a substrate having a top surface and a bottom surface;
a plurality of display pixels;
a plurality of first reflective surfaces; and
a plurality of optical detector elements;
wherein the plurality of display pixels, the plurality of first reflective surfaces; and
the plurality of optical detector elements are arranged in a single layer on the top surface of the substrate.
2. The sensor assembly of claim 1 , further comprising a transparent layer disposed above the substrate.
3. The sensor assembly of claim 2 , further comprising a plurality of second reflective surfaces above the transparent layer.
4. The sensor assembly of claim 3 , further comprising a blocking layer above the transparent layer; wherein the blocking layer is a light absorbing material forming a plurality of apertures.
5. The sensor assembly of claim 1 , further comprising a blocking layer having first portions above and parallel to a plane of the optical detector elements and second portions in an area that at least partially surrounds the optical detector elements.
6. The sensor assembly of claim 5 , wherein the second portions are in a plane substantially perpendicular to the plane of the optical detector elements.
7. The sensor assembly of claim 1 , wherein the plurality of first reflective surfaces comprise mirrored surfaces.
8. The sensor assembly of claim 1 , wherein the first reflective surfaces are surrounded by a light absorbing material.
9. The sensor assembly of claim 8 , wherein the first reflective surfaces are recessed relative to the light absorbing material.
10. A method for making an optical sensor assembly for integration in a display, comprising:
forming a substrate;
forming a plurality of optical detector elements on the substrate;
forming a plurality of reflective surfaces on the substrate; and
forming a plurality of display pixels on the substrate,
wherein the plurality of display pixels, the plurality of first reflective surfaces, and the plurality of optical detector elements are arranged in a single layer on the substrate.
11. The method of claim 10 , further comprising:
forming a transparent layer above the plurality of optical detector elements and the plurality of reflective surfaces;
forming a second plurality of reflective surfaces above the transparent layer; and
forming a light blocking layer above the transparent layer, the light blocking layer having a plurality of apertures.
12. The method of claim 11 , further comprising:
removing portions of a bottom of the transparent layer to form etched portions and forming a light absorbing layer in the etched portions.
13. The method of claim 10 , further comprising:
coating the substrate with a light absorbing layer having openings over the plurality of optical detector elements, the plurality of display pixels, and at least portions of the plurality of reflective surfaces.
14. The method of claim 10 , further comprising:
coating the substrate with a light absorbing layer before forming the plurality of optical detector elements, the plurality of reflective surfaces, and the plurality of display pixels on the substrate.
15. The method of claim 10 , wherein forming the plurality of reflective surfaces comprises:
forming a continuous mirrored surface; and
selectively disposing a light absorbing material on the continuous mirrored surface to form the plurality of reflective surfaces.
16. A display including a sensor for imaging a biometric input object, comprising:
a plurality of display pixels;
a transparent layer;
a plurality of mirrors positioned above the transparent layer;
a reflective layer positioned below the transparent layer configured to receive light transmitted through a set of apertures and to reflect the light towards at least one of the plurality of mirrors; and
a plurality of detector elements positioned below the transparent layer and configured to detect the light.
17. The display of claim 16 , wherein the plurality of detector elements are thin film photodetectors.
18. The display of claim 16 , wherein at least two widths of the following are adjusted to limit an acceptance angle of light: (a) a width of apertures in the set of apertures, (b) a width of the plurality of mirrors, (c) a width of reflective surfaces in the reflective layer, and (d) a width of surfaces of the detector elements.
19. The display of claim 16 wherein the reflective layer comprises mirrored surfaces surrounded by light absorbing material.
20. The display of claim 16 , further comprising:
a blocking layer, wherein the blocking layer includes first portions above and parallel to a plane of the plurality of detector elements and second portions in an area that at least partially surrounds the plurality of detector elements, wherein the second portions are in a plane substantially perpendicular to the plane of the plurality of detector elements.