Optical fingerprint sensing module
An optical fingerprint sensing module for sensing a fingerprint pattern of a finger placed on an upper surface of a display panel module is provided, wherein light is generated by the display panel module and reflected by the finger. The optical fingerprint sensing module includes a substrate, an image sensor disposed above the substrate, a collimating layer disposed above the image sensor, a light permeable layer disposed above the collimating layer, and a pinhole layer disposed above the light permeable layer. The collimating layer has a plurality of collimating holes, and the pinhole layer has a plurality of pinholes, wherein the number of collimating holes is greater than the number of pinholes. Light is reflected by the finger and then sequentially propagates through the pinholes, the light permeable layer, and the collimating holes to reach the image sensor.
1. An optical fingerprint sensing module for sensing a fingerprint pattern of a finger placed on an upper surface of a display panel module, wherein light is generated by the display panel module and reflected by the finger, the optical fingerprint sensing module comprising:
a substrate;
an image sensor, disposed above the substrate;
a collimating layer, disposed above the image sensor and comprising a plurality of collimating holes;
a light permeable layer, disposed above the collimating layer;
a pinhole layer, disposed on the light permeable layer and comprising a plurality of pinholes, wherein the number of collimating holes is greater than the number of pinholes, and light is reflected by the finger and then sequentially propagates through the pinholes, the light permeable layer, and the collimating holes to reach the image sensor.
2. The optical fingerprint sensing module as claimed in claim 1 , wherein each of the pinholes has a diameter W 1 , and each of the collimating holes has a diameter W 2 , wherein W 1 ≥W 2 .
3. The optical fingerprint sensing module as claimed in claim 2 , wherein a distance H is formed between a top surface of the pinhole layer and a bottom surface of the collimating layer, and the collimating layer has a height H 5 , wherein the ratio of H to H 5 is from 5 to 8.
4. The optical fingerprint sensing module as claimed in claim 3 , wherein the ratio of H to W 2 is from 80 to 120.
5. The optical fingerprint sensing module as claimed in claim 3 , wherein the ratio of H 5 to W 2 is from 10 to 50.
6. The optical fingerprint sensing module as claimed in claim 1 , wherein the pitch of the pinholes is greater than the pitch of the collimating holes.
7. The optical fingerprint sensing module as claimed in claim 1 , wherein the pitch of the pinholes is from 20 um to 50 um.
8. The optical fingerprint sensing module as claimed in claim 1 , further comprising an optical film disposed between the collimating layer and the image sensor.
9. The optical fingerprint sensing module as claimed in claim 8 , wherein the optical film is an infrared cut-off filter film.
10. The optical fingerprint sensing module as claimed in claim 1 , wherein the image sensor comprises a plurality of pixel units, and each of the pixel units comprises at least a photosensitive element, wherein the number of pinholes is equal to the number of pixel units.
11. The optical fingerprint sensing module as claimed in claim 1 , wherein the pinhole layer comprises metal or black photoresist.
12. The optical fingerprint sensing module as claimed in claim 1 , further comprising a plurality of micro-lenses disposed on the light permeable layer and respectively received in the pinholes.
13. The optical fingerprint sensing module as claimed in claim 1 , wherein the pinhole layer is formed on the light permeable layer by Chemical Vapor Deposition (CVD), evaporation, sputtering, coating, dispensing, electroplating, or electroless plating.
14. The optical fingerprint sensing module as claimed in claim 1 , wherein the display panel module may be an Organic Light-Emitting Diode (OLED) display module or TFT-LCD module.