Fingerprint recognition sensor and optical element

Patent metadata

Field	Value
Publication number	US-12505695-B2
Application number	US-202418828794-A
Country	US
Kind code	B2
Filing date	Sep 9, 2024
Priority date	Mar 30, 2021
Publication date	Dec 23, 2025
Grant date	Dec 23, 2025

Abstract

A sensor including a light-receiving element; and an optical element that includes near infrared absorbing dichroic substance. The optical element has an absorption axis with respect to near infrared light in an in-plane direction. When linearly polarized light of near infrared light orthogonal to the absorption axis is radiated from a normal direction of the optical element and from a direction inclined by 45° from the normal direction at an azimuthal angle orthogonal to the absorption axis, an absorbance during the radiation from the direction inclined by 45° from the normal direction is more than an absorbance during the radiation from the normal direction.

First claim

What is claimed is:

1 . A sensor comprising:
a light-receiving element; and an optical element that includes a near infrared absorbing dichroic substance, the optical element has an absorption axis with respect to near infrared light in an in-plane direction, and in a case where linearly polarized light of near infrared light orthogonal to the absorption axis is radiated from a normal direction of the optical element and from a direction inclined by 45° from the normal direction at an azimuthal angle orthogonal to the absorption axis, an absorbance during the radiation from the direction inclined by 45° from the normal direction is more than an absorbance during the radiation from the normal direction.

2 . The sensor according to claim 1 ,
wherein the optical element includes a first layer that includes a near infrared absorbing dichroic substance and has an absorption axis with respect to near infrared light in an in-plane direction and a second layer that includes a near infrared absorbing dichroic substance and has an absorption axis with respect to near infrared light in a thickness direction.

3 . The sensor according to claim 2 ,
wherein the first layer and the second layer are layers that do not substantially absorb visible light.

4 . The sensor according to claim 1 ,
wherein the optical element consists of a single layer that includes a near infrared absorbing dichroic substance and has an absorption axis with respect to near infrared light in an in-plane direction, and in a cross-section taken along the absorption axis, the optical element does not have absorption anisotropy with respect to near infrared light.

5 . The sensor according to claim 4 ,
wherein the near infrared absorbing dichroic substance is a substance that does not substantially absorb visible light.

6 . The sensor according to claim 4 ,
wherein the near infrared absorbing dichroic substance is a disk-like colorant.

Assignees

• Fujifilm Corp

Inventors

• Himeno Ryoji
• Morishima Shinichi
• Hirai Yuki
• Kamo Makoto
• Sekiguchi Megumi

Classifications

• G02B5/208 Primary

  for use with infrared or ultraviolet radiation, e.g. for separating visible light from infrared and/or ultraviolet radiation · CPC title

• G06V40/1318 Primary

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

• G02B5/22

  Absorbing filters {(G02B5/201 - G02B5/208 take precedence)} · CPC title

• G02B5/30

  Polarising elements (light-modulating devices with active elements G02F1/00) · CPC title

• G01N21/359

  using near infrared light · CPC title