Fingerprint Detection with Transparent Cover

Patent metadata

Field	Value
Publication number	US-2016247010-A1
Application number	US-201514628293-A
Country	US
Kind code	A1
Filing date	Feb 22, 2015
Priority date	Feb 22, 2015
Publication date	Aug 25, 2016
Grant date	—

Abstract

An electronic device includes a transparent cover and a light source disposed at an edge of the transparent cover. The light source is configured to inject light into the transparent cover. The transparent cover guides the light until interaction with a fingerprint ridge at the transparent cover. The electronic device further includes a filter disposed along the transparent cover. The filter is configured to selectively allow the light scattered by the fingerprint ridge to pass through the filter. A detector generates a signal indicative of the scattered light allowed through the filter.

First claim

What is claimed is:

1 . An electronic device comprising:
a transparent cover; a light source adjacent to the transparent cover, the light source being configured to inject light into the transparent cover, the transparent cover being configured to guide the light to an interaction at the transparent cover; a filter disposed along the transparent cover, the filter being configured to selectively allow the light scattered by the interaction to pass through the filter; and a detector configured to generate a signal indicative of the scattered light allowed through the filter.

2 . The electronic device of claim 1 , wherein:
the filter comprises an optical fiber faceplate disposed between the transparent cover and the detector, each optical fiber of the optical fiber faceplate being oriented to guide the light scattered by the interaction to the detector if the light is directed at an angle within a cone of acceptance of the optical fiber; and the filter is configured to prevent the light scattered by the interaction from reaching the detector if the light is not directed at an angle within the cone of acceptance of each optical fiber of the optical fiber faceplate.

3 . The electronic device of claim 2 , wherein the filter further comprises a plurality of opaque regions, each opaque region being interstitially disposed between respective adjacent optical fibers of the optical fiber faceplate and configured to absorb the light scattered by the interaction and not directed at an angle within the cone of acceptance of each optical fiber of the optical fiber faceplate.

4 . The electronic device of claim 3 , wherein each optical fiber of the optical fiber faceplate and the plurality of opaque regions are arranged in a fiber bundle, the fiber bundle having a first end disposed adjacent the transparent cover and a second end disposed adjacent the detector.

5 . The electronic device of claim 1 , wherein the transparent cover, the filter, and the detector are curved.

6 . The electronic device of claim 1 , wherein the transparent cover, the filter, and the detector are flexible.

7 . The electronic device of claim 1 , wherein:
the filter comprises a film disposed in a stacked arrangement between the transparent cover and the detector; and the film comprises a material having a refractive index lower than a refractive index of the transparent cover.

8 . The electronic device of claim 7 , wherein the refractive index of the film is less than 1 .

9 . The electronic device of claim 1 , wherein the interaction is between the light and a fingerprint ridge.

10 . The electronic device of claim 1 , further comprising:
a touch sensing unit disposed along the transparent cover; and a display module disposed along the transparent cover in a display area adjacent a fingerprint sensor area in which the filter and the detector are disposed; wherein the transparent cover and the touch sensing unit extend across the display area and the fingerprint sensor area.

11 . The electronic device of claim 1 , wherein the transparent cover has a thickness greater than about 300 microns.

12 . The electronic device of claim 1 , wherein:
the transparent cover, the filter, and the detector are disposed in a layered arrangement; the filter is secured to the transparent cover by an adhesive layer of the layered arrangement; and the adhesive layer has a refractive index that does not match a refractive index of the transparent cover.

13 . An electronic device comprising:
a transparent cover having an exposed front face and a rear face opposite the front face; a light source disposed at an edge of the transparent cover, the light source being configured to inject light into the transparent cover, the transparent cover guiding the light until interaction with a fingerprint ridge at the front face of the transparent cover; a filter layer disposed along the rear face of the transparent cover, the filter layer being configured to selectively allow the light scattered by the fingerprint ridge to pass through the filter layer; and a photodetector circuit disposed along the filter layer, the photodetector circuit being configured to generate an output indicative of the fingerprint ridge based on the scattered light allowed through the filter layer.

14 . The electronic device of claim 13 , wherein:
the filter layer comprises a plurality of optical fibers disposed between the transparent cover and the photodetector circuit, each optical fiber being oriented to guide the light scattered by the fingerprint ridge to the photodetector circuit if the light is directed at an angle within a cone of acceptance of the optical fiber; and the filter layer is configured to prevent the light scattered by the fingerprint ridge from reaching the photodetector circuit if the light is not directed at an angle within the cone of acceptance of a respective optical fiber of the plurality of optical fibers.

15 . The electronic device of claim 13 , wherein:
the filter layer comprises a film disposed in a stacked arrangement between the transparent cover and the photodetector circuit; and the film comprises a material having a refractive index lower than a refractive index of the transparent cover.

16 . The electronic device of claim 13 , further comprising:
a touch sensing unit disposed along the transparent cover; and a display module disposed along the transparent cover in a display area adjacent a fingerprint sensor area in which the filter layer and the photodetector circuit are disposed; wherein the transparent cover and the touch sensing unit extend across the display area and the fingerprint sensor area.

17 . An electronic device comprising:
a transparent cover; a touch sensing unit disposed along the transparent cover; a display module disposed along the transparent cover in a display area adjacent a fingerprint sensor area; a light source disposed at an edge of the transparent cover, the light source being configured to inject light into the transparent cover, the transparent cover guiding the light until interaction with a fingerprint ridge at the transparent cover; a filter layer disposed along the transparent cover in the fingerprint sensor area, the filter layer being configured to selectively allow the light scattered by the fingerprint ridge to pass through the filter layer; and a photodetector circuit disposed along the filter layer, the photodetector circuit being configured to generate an output indicative of the fingerprint ridge based on the scattered light allowed through the filter layer; wherein the transparent cover and the touch sensing unit extend across the display area and the fingerprint sensor area.

18 . The electronic device of claim 17 , wherein:
the filter layer comprises a plurality of optical fibers disposed between the transparent cover and the photodetector circuit, each optical fiber being oriented to guide the light scattered by the fingerprint ridge to the photodetector circuit if the light is directed at an angle within a cone of acceptance of the optical fiber; and the filter layer is configured to prevent the light scattered by the fingerprint ridge from reaching the photodetector circuit if the light is not directed at an angle within the cone of acceptance of a respective optical fiber of the plurality of optical fibers.

19 . The electronic device of claim 17 , wherein:
the filter layer comprises a film disposed in a stacked arrangement between the transparent cover and the photodetect

Assignees

• Microsoft Technology Licensing Llc

Inventors

• Huang Jiandong
• Chen Liying

Classifications

• G06K9/00046 Primary

  Physics · mapped topic

• G06K9/00087

  Physics · mapped topic

• G02B5/20

  Filters (polarising elements G02B5/30) · CPC title

• G06V40/1318 Primary

  using electro-optical elements or layers, e.g. electroluminescent sensing · CPC title

• G06V40/1324 Primary

  by using geometrical optics, e.g. using prisms (G06V40/1312 takes precedence) · CPC title