Fingerprint sensor and display device

Patent metadata

Field	Value
Publication number	US-11113503-B2
Application number	US-201816772463-A
Country	US
Kind code	B2
Filing date	Nov 26, 2018
Priority date	Dec 28, 2017
Publication date	Sep 7, 2021
Grant date	Sep 7, 2021

Abstract

A fingerprint sensor for a display device capable of suppressing loss of light due to diffraction of light and a display device with this fingerprint sensor are provided. A fingerprint sensor for a display device having a plurality of photosensors arranged in a matrix, each of the photosensors has a semiconductor film for converting incident light into an electric signal, and a bottom gate electrode as a light shielding film arranged on a lower layer side of the semiconductor film for blocking incident light from the lower layer side to the semiconductor film, wherein the bottom gate electrode has four corner portions in an outer contour shape in a top view, and each of the corner portions is rounded.

First claim

The invention claimed is:

1. A fingerprint sensor in a display device, the fingerprint sensor comprising:
a plurality of photosensors arranged in a matrix,
wherein each of the photosensors comprises:
a semiconductor film configured to convert incident light into an electrical signal; and
a light shielding film
that is disposed on a lower layer side than the semiconductor film, and
configured to block incidence of light to the semiconductor film from the lower layer side, and

wherein an outer contour shape in a top view of the light shielding film is rounded to shorten a circumferential length, which suppresses diffraction of light from the lower layer side.

2. The fingerprint sensor according to claim 1 , wherein the outer contour shape in a top view of the semiconductor film is rounded to correspond to the light shielding film.

3. A fingerprint sensor in a display device, the fingerprint sensor comprising:
a plurality of photosensors arranged in a matrix,
wherein each of the photosensors comprises:
a semiconductor film configured to convert incident light into an electrical signal, and
a light shielding film
that is disposed on a lower layer side than the semiconductor film, and
configured to block incidence of light to the semiconductor film from the lower layer side,

wherein the light shielding film has four corner portions in outer contour shape in a top view, and
wherein each of the four corner portions has a radius of curvature that exceeds a radius of curvature that occurs at corner portions of the light shielding film due to a forming process, the forming process including a photolithography process to shorten a circumferential length, which suppresses diffraction of light from the lower layer side.

4. The fingerprint sensor according to claim 3 , wherein the radius of curvature of each of the four corner portions is 2 μm or more.

5. A fingerprint sensor in a display device, the fingerprint sensor comprising:
a plurality of photosensors arranged in a matrix,
wherein each of the photosensors comprises:
a semiconductor film configured to convert incident light into an electrical signal; and
a light shielding film
that is disposed on a lower layer side than the semiconductor film, and
configured to block incidence of light from the lower layer side to the semiconductor film, and

wherein an outer contour shape of the light-shielding film in a top view is entirely formed by curves to shorten a circumferential length, which suppresses diffraction of light from the lower layer side.

6. The fingerprint sensor of claim 5 , wherein the outer contour shape in a top view of the semiconductor film is entirely formed by curves to correspond to the outer contour shape of the light shielding film.

7. The fingerprint sensor according to claim 5 , wherein the light shielding film has a circular outer contour shape in the top view.

8. The fingerprint sensor according to claim 7 , wherein the outer contour shape of the semiconductor film in a top view is concentric with the light shielding film.

Assignees

• Connectec Japan Corp
• Fujikin Kk

Inventors

• Komatsu Hiroshi
• Suzuki Akane
• Kimura Jun
• Kojima Kensuke

Classifications

• G06V40/1318 Primary

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

• G06F3/03547

  Touch pads, in which fingers can move on a surface · CPC title

• G06F3/042

  by opto-electronic means · CPC title

• G06K9/0004 Primary

  Physics · mapped topic