Biometric imaging device and method for manufacturing a biometric imaging device

1. A method for manufacturing a biometric imaging device configured to capture an image of an object in contact with an outer surface of the imaging device, the method comprising:

providing an at least partially transparent display panel having a repeating transmission pattern defined by an array of unit cells, each unit cell having the same transmission pattern;

providing an image sensor comprising a photodetector pixel array; and

providing a collimator layer arranged between the display panel and the image sensor, the collimator layer defining a plane and comprising a plurality of first collimating structures having a first collimator opening size and a plurality of second collimating structures having a second collimator opening size, the second collimator opening size being different from the first collimator opening size, wherein the respective collimator opening size and relative location of the first and second collimating structure in relation to the display unit cell is based on the transmission pattern of the display unit cell, and wherein one or more of the plurality of first collimating structures are arranged next to one or more of the plurality of second collimating structures in the plane of the collimator layer.

2. The method according to claim 1 , wherein providing the collimator layer comprises:

attaching a collimator substrate to the image sensor:

forming the plurality of first collimating structures and the plurality of second collimating structures in the substrate; and

attaching the display panel to the collimator substrate.

3. The method according to claim 2 , wherein forming the plurality of first collimating structures and the plurality of second collimating structures in the substrate comprises forming openings in the collimator substrate.

4. The method according to claim 2 , wherein the plurality of first collimating structures and the plurality of second collimating structures are formed by lithography and etching.

5. The method according to claim 2 , wherein the collimator substrate is a silicon substrate.

6. The method according to claim 1 , wherein providing the collimator layer arranged between the display panel and the image sensor comprises:

providing a collimator layer comprising the plurality of first collimating structures and the plurality of second collimating structures in the substrate;

attaching the collimator layer to the image sensor; and

attaching the display panel to the collimator substrate.

7. The method according to claim 1 , wherein the plurality of first collimating structures and the plurality of second collimating structures extend through the collimator layer.

8. A biometric imaging device configured to capture an image of an object in contact with an outer surface of the biometric imaging device, the biometric imaging device comprising:

an at least partially transparent display panel comprising a repeating transmission pattern defined by an array of display unit cells, each display unit cell having the same transmission pattern;

an image sensor comprising a photodetector pixel array arranged underneath the display panel; and

a collimator layer arranged between the display panel and the image sensor, the collimator layer defining a plane and comprising a plurality of first collimating structures having a first collimator opening size and a plurality of second collimating structures having a second collimator opening size, the second collimator opening size being different from the first collimator opening size, wherein the respective collimator opening size and relative location of the first and second collimating structure in relation to the display unit cell is based on the transmission pattern of the display unit cell, and wherein one or more of the plurality of first collimating structures are arranged next to one or more of the plurality of second collimating structures in the plane of the collimator layer.

9. The biometric imaging device according to claim 8 , wherein the collimator layer comprises at least one of the first collimating structure and at least one of the second collimating structure per display unit cell.

10. The biometric imaging device according to claim 9 , wherein each display unit cell comprises a first portion having a first transparency and a second portion having a second transparency, the first transparency being lower than the second transparency, and wherein a first collimating structure larger than a second collimating structure is aligned with the first portion of the display unit cell and the second collimating structure is aligned with the second portion of the display unit cell.

11. The biometric imaging device according to claim 8 , wherein the display unit cell has a uniform transparency.

12. The biometric imaging device according to claim 8 , wherein each first collimating structure is aligned with a respective display unit cell for a first sub-set of display unit cells, and each second collimating structure is aligned with a respective display unit cell for a second sub-set of display unit cells, the second sub-set of display unit cells being non-overlapping with the first sub-set of display unit cells.

13. The biometric imaging device according to claim 8 , further comprising a pinhole layer arranged between the collimator layer and the image sensor.

14. The biometric imaging device according to claim 8 , further comprising a pinhole layer arranged between the collimator layer and the display panel.

15. The biometric imaging device according to claim 8 , wherein at least one of the first and second collimating structures is a circular collimating structure.

16. The biometric imaging device according to claim 8 , wherein at least one of the first and second collimating structures is a rectangular collimating structure.

17. The biometric imaging device according to claim 8 , wherein an aspect ratio between the height and width of each of the first and the second collimating structures is in the range of 5:1 to 20:1.

18. The biometric imaging device according to claim 8 , wherein the plurality of first collimating structures and the plurality of second collimating structures extend through the collimator layer.