Optical sensor with substrate light filter
An optical biometric sensor is disclosed. The optical biometric sensor includes a filter layer having a top surface and a bottom surface. The filter layer includes a light filter including a blocking material forming an array of apertures; a substrate including an electrical interconnect comprising a set of electrical conductors. The biometric sensor further includes an optical sensor including an array of sensing elements mounted to the bottom surface of the substrate, wherein sensing elements in the array of sensing elements sensors are aligned with the array of apertures and electrically connected to the electrical interconnect.
1. An optical imaging device for imaging a biometric, comprising:
a filter layer having a top surface and a bottom surface, the filter layer comprising:
a light filter including a blocking material forming an array of apertures;
a substrate including an electrical interconnect comprising a set of electrical conductors; and
an optical sensor including an array of sensing elements, the optical sensor being mounted to the bottom surface of the filter layer, wherein sensing elements of the array of sensing elements are aligned with the light filter and electrically connected to the electrical interconnect,
wherein the light filter further comprises:
a first blocking layer having a first array of openings defining a bottom of the array of apertures;
a second blocking layer having a second array of openings defining a top of the array of apertures; and
a transparent material disposed between the first blocking layer and the second blocking layer, and wherein the first array of openings and the second array of openings have different diameters.
2. The optical imaging device of claim 1 , wherein the first blocking layer and the second blocking layer comprise metal, and wherein the transparent material comprises a dielectric material.
3. The optical imaging device of claim 1 , wherein the transparent material comprises an array of voids aligned with the first array of openings and the second array of openings, and wherein sidewalls of the voids are coated with a light absorbing material.
4. The optical imaging device of claim 1 , wherein the light filter is integral with the substrate.
5. The optical imaging device of claim 1 , wherein the substrate forms a void, wherein the light filter is attached to the substrate and at least partially disposed in the void.
6. The optical imaging device of claim 1 , wherein the substrate forms a void, wherein the light filter is attached to the optical sensor and at least partially disposed in the void.
7. The optical imaging device of claim 1 , wherein the array of sensing elements is formed in a semiconductor die.
8. The optical imaging device of claim 7 , wherein the semiconductor die is a flip chip.
9. The optical imaging device claim 1 , further comprising a cover layer disposed above the filter layer.
10. The optical imaging device of claim 9 , wherein the cover layer includes an organic light emitting diode (OLED) display.
11. A fingerprint sensor, comprising:
a filter layer comprising a substrate having a top surface and a bottom surface, the filter layer comprising:
a light filter formed in the substrate including a plurality of metal layers forming an array of apertures;
an electrical interconnect formed in the substrate comprising a set of electrical conductors; and
an optical sensor including an array of photosensors, the optical sensor being mounted to the bottom surface of the filter layer, wherein the array of photosensors are aligned with the light filter and electrically connected to the electrical interconnect,
wherein the light filter further comprises:
a first metal layer having a first array of openings defining a bottom of the array of apertures;
a second metal layer having a second array of openings defining a top of the array of apertures; and
a transparent material disposed between the first metal layer and the second metal layer, and wherein the first array of openings and the second array of openings have different diameters.
12. The fingerprint sensor of claim 11 , wherein the optical sensor is a flip chip bonded to the bottom surface of the substrate.
13. The fingerprint sensor of claim 11 , further comprising a cover layer above the filter layer including an organic light emitting diode (OLED) display.
14. The fingerprint sensor of claim 11 , wherein the transparent material comprises an array of voids aligned with the first array of openings and the second array of openings, and wherein sidewalls of the voids are coated with a blocking material.
15. A method for making an optical biometric sensor, comprising:
forming a light filter substrate having a top side and bottom side, comprising:
forming a first metal layer having a first array of apertures;
forming a first transparent layer made of dielectric material above the first metal layer;
forming a second metal layer above the first transparent layer having a second array of apertures, the second array of apertures being aligned with the first array of apertures and the first array of apertures and the second array of apertures having different diameters;
forming an electrical interconnect comprising one or more electrical conductors; and
attaching an optical sensor to the bottom side of the light filter substrate, the optical sensor comprising an array of sensor elements, the array of sensor elements being aligned with the first array of apertures and second array of apertures, wherein the optical sensor is electrically connected to the electrical interconnect.
16. The method of claim 15 , further comprising:
removing the dielectric material between the first and second array of apertures.
17. The method of claim 16 , further comprising:
forming metal sidewalls between the first and second array of apertures.
18. The method of claim 15 , wherein forming the substrate further comprising:
forming a second transparent layer made of the dielectric material above the second metal layer; and
forming a third metal layer above the second transparent layer having a third array of apertures, the third array of apertures being aligned with the first and second array of apertures.
19. The method of claim 15 , wherein the one or more of the electrical conductors are electrically connected to the first or second metal layer.