US 12,223,761 B2Granted

Display device and fingerprint sensing circuit

AssigneeHimax Technologies Limited

InventorsYaw-Guang Chang, Jia-Ming He, Zong-You Hou

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Abstract

The fingerprint sensing circuit includes a photo detector, a capacitor, a current mirror and a switch circuit. The capacitor has a first terminal electrically connected to the first terminal of the photo detector. The current mirror has an input terminal electrically connected to the first terminal of the photo detector and an output terminal electrically connected to a sensing line. In an exposure period, the switch circuit turns off the current mirror. In a sensing period, the switch circuit turns on the current mirror to generate a current on the sensing line, and the detecting circuit is configured to generate a fingerprint signal according to the current.

Claims15

Dependent claims

A display device comprising:

a detecting circuit;
and
a display panel comprising a plurality of pixel units and a plurality of fingerprint sensing circuits, wherein each of the fingerprint sensing circuits corresponds to at least one of the pixel units, electrically connected to the detecting circuit through a sensing line, and comprises:
a photo detector having a first terminal and a second terminal;
a capacitor having a first terminal electrically connected to the first terminal of the photo detector;
a current mirror having an input terminal electrically connected to the first terminal of the photo detector and an output terminal electrically connected to the sensing line;
and
a switch circuit configured to control the current mirror,
wherein in an exposure period, the switch circuit is configured to turn off the current mirror,
wherein in a sensing period, the switch circuit is configured to turn on the current mirror to generate a current on the sensing line, and the detecting circuit is configured to generate a fingerprint signal according to the current.

7 more elements

A fingerprint sensing circuit disposed in a display panel and corresponding to at least one pixel unit of the display panel, wherein the display panel comprises a sensing line electrically connected to a detecting circuit, the fingerprint sensing circuit comprises:

a photo detector having a first terminal and a second terminal;
a capacitor having a first terminal electrically connected to the first terminal of the photo detector;
a current mirror having a input terminal electrically connected to the first terminal of the photo detector and an output terminal electrically connected to the sensing line;
and
a switch circuit configured to control the current mirror,
wherein in an exposure period, the switch circuit is configured to turn off the current mirror,
wherein in a sensing period, the switch circuit is configured to turn on the current mirror to generate a current on the sensing line, and the detecting circuit is configured to generate a fingerprint signal according to the current.

4 more elements

Dependencies are inferred from the claim text.