Optical filter and imaging device

Patent metadata

Field	Value
Publication number	US-2017192144-A1
Application number	US-201715466118-A
Country	US
Kind code	A1
Filing date	Mar 22, 2017
Priority date	Apr 23, 2015
Publication date	Jul 6, 2017
Grant date	—

Abstract

An optical filter includes: an absorption layer containing a first near-infrared absorbent having a maximum absorption in a wavelength of 660 to 785 nm, and satisfying (i-1) in 620 to 670 nm, on a shorter wavelength side of a wavelength λ (DA_T min ) exhibiting the maximum absorption, there is a wavelength λSh (DA_T50%) at which a transmittance becomes 50%; and a reflection layer formed of a dielectric multilayered film satisfying (ii-1) in 670 to 1200 nm, there is a near-infrared reflection band in which a transmittance with respect to light at an incident angle of 0° becomes 50% or less, and a wavelength λSh (A2_Ts50%) at which a transmittance of light of an s polarization component out of light at an incident angle of 30° becomes 50%, on a shorter wavelength side of the near-infrared reflection band, is positioned on a longer wavelength side of the wavelength λSh (DA_T50%).

First claim

What is claimed is:

1 . An optical filter, comprising: an absorption layer containing a near-infrared absorbent having a maximum absorption in a wavelength of 660 to 785 nm, and satisfying the following requirement (i-1); and a reflection layer formed of a dielectric multilayered film satisfying the following requirement (ii-1),
(i-1) in a wavelength of 620 to 670 nm, on a shorter wavelength side of a wavelength (DA_T min ) exhibiting the maximum absorption, there is a wavelength λSh (DA_T50%) at which a transmittance becomes 50%, and (ii-1) in a wavelength of 670 to 1200 nm, there is a near-infrared reflection band in which a transmittance with respect to light at an incident angle of 0° becomes 50% or less, and a wavelength λSh (A2_Ts50%) at which a transmittance of light of an s polarization component out of light at an incident angle of 30° becomes 50%, on a shorter wavelength side of the near-infrared reflection band, is positioned on a longer wavelength side of the wavelength λSh (DA_T50%).

2 . The optical filter according to claim 1 , wherein
the reflection layer satisfies the following requirement (ii-2), (ii-2) on a shorter wavelength side of the near-infrared reflection band, a wavelength λSh (A2_Tp50%) at which a transmittance of light of a p polarization component out of light at an incident angle of 30° becomes 50%, and the wavelength λSh (A2_Ts50%) have a relation of 0 nm<λSh (A2_Tp50%)−λSh (A2_Ts50%)≦20 nm.

3 . The optical filter according to claim 1 , wherein
the absorption layer satisfies the following requirements (i-2) and (i-3), (i-2) in a wavelength of 640 to 700 nm, there is a wavelength λSh (DA_T15%) at which a transmittance becomes 15%, and a relation of λSh (DA_T50%)<λSh (DA_T15%)<(DA_T min ) is satisfied, and (i-3) in a wavelength of 740 to 840 nm, there are a wavelength λLo (DA_T50%) at which a transmittance becomes 50% and a wavelength λLo (DA_T15%) at which a transmittance becomes 15%, and a relation of λ (DA_T min )<λLo (DA_T15%)<λLo (DA_T50%) is satisfied.

4 . The optical filter according to claim 1 , wherein
the absorption layer contains a near-ultraviolet absorbent having a maximum absorption in a wavelength of 370 to 405 nm, and satisfies the following requirement (i-4), and the reflection layer satisfies the following requirement (ii-3), (i-4) in a wavelength of 400 to 420 nm, on a longer wavelength side of a wavelength λ (DU_T min ) exhibiting the maximum absorption, there is a wavelength λLo (DU_T50%) at which a transmittance becomes 50%, and (ii-3) in a wavelength of 300 to 420 nm, there is a near-ultraviolet reflection band in which a transmittance with respect to light at an incident angle of 0° becomes 50% or less, and a wavelength λLo (U1 T50%) at which a transmittance becomes 50%, on a longer wavelength side in the near-ultraviolet reflection band, is positioned on a shorter wavelength side of the wavelength λLo (DU_T50%).

5 . The optical filter according to claim 4 , wherein
the absorption layer satisfies the following requirement (i-5), and the reflection layer satisfies the following requirement (ii-4), (i-5) on a shorter wavelength side of the wavelength λ (DU_T min ), there is a wavelength λSh (DU_T50%) at which a transmittance becomes 50%, and (ii-4) a wavelength λLo (U1 Tp50%) at which a transmittance of light of a p polarization component out of light at an incident angle of 30° becomes 50%, on a longer wavelength side in the near-ultraviolet reflection band, is positioned on a longer wavelength side of the wavelength λSh (DU_T50%).

6 . The optical filter according to claim 1 , wherein
the reflection layer has a first reflection layer having a first near-infrared reflection band in which a transmittance with respect to light at an incident angle of 0° in a first wavelength region within a wavelength of 700 to 1200 nm becomes 50% or less, and a second reflection layer having a second near-infrared reflection band in which a transmittance with respect to light at an incident angle of 0° in a second wavelength region on a shorter wavelength side of the first wavelength region within the wavelength of 700 to 1200 nm becomes 50% or less, and the first near-infrared reflection band and the second near-infrared reflection band form the near-infrared reflection band.

7 . The optical filter according to claim 6 , wherein
the first reflection layer and the second reflection layer are provided by being separated from each other.

8 . The optical filter according to claim 6 , wherein
the wavelength λLo (DA_T15%) is positioned on a longer wavelength side of a wavelength λSh (A2_T15%) at which a transmittance of light at an incident angle of 0° becomes 15%, on a shorter wavelength side in the second near-infrared reflection band.

9 . The optical filter according to claim 6 , wherein
a wavelength λLo (A1_Tp15%) at which a transmittance of light of a p polarization component out of light at an incident angle of 30° becomes 15%, on a longer wavelength side in the first near-infrared reflection band, is a wavelength longer than a wavelength of 1150 nm.

10 . An optical filter, comprising: an absorption layer containing a first near-infrared absorbent having a maximum absorption in a wavelength of 660 to 785 nm, and a second near-infrared absorbent having a maximum absorption in a wavelength of 800 to 920 nm, and satisfying the following requirement (I-1); and a reflection layer formed of a dielectric multilayered film satisfying the following requirement (II-1),
(I-1) there is a wavelength λSh (DA_T50%) at which a transmittance becomes 50% in a wavelength of 620 to 670 nm, on a shorter wavelength side of a wavelength λ (DA_T min ) at which the first near-infrared absorbent exhibits the maximum absorption, there is a wavelength λLo (DB_T50%) at which a transmittance becomes 50% in a wavelength of 900 to 970 nm, on a longer wavelength side of a wavelength λ (DB_T min ) at which the second near-infrared absorbent exhibits the maximum absorption, and a relation of λSh (DA_T50%)<(DA_T min )<λ (DB_T min )<λLo (DB_T50%) is satisfied, and (II-1) in a wavelength of 670 to 1200 nm, there is a near-infrared reflection band in which a transmittance with respect to light at an incident angle of 0° becomes 50% or less, a relation among a wavelength λSh (A1_T50%) at which a transmittance becomes 50% on a shorter wavelength side in the near-infrared reflection band, the wavelength λ (DB_T min ), and the wavelength λLo (DB_T50%) is expressed as λ (DB_T min )<λSh (A1_T50%)<λLo (DB_T50%), and a wavelength λLo (A1_Tp15%) at which a transmittance of light of a p polarization component out of light at an incident angle of 30° becomes 15%, on a longer wavelength side in the near-infrared reflection band, is a wavelength longer than a wavelength of 1150 nm.

11 . The optical filter according to claim 10 , wherein
the absorption layer contains a near-ultraviolet absorbent having a maximum absorption in a wavelength of 370 to 405 nm, and satisfies the following requirement (I-2), and the reflection layer satisfies the following requirement (II-2), (I-2) in a wavelength of 400 to 420 nm, on a longer wavelength side of a wavelength (DU_T min ) exhibiting the maximum absorption, there is a wavelength λLo (DU_T50%) at which a transmittance becomes 50%, and (II-2) in a wavelength of 300 to 420 nm, there is a near-ultraviolet reflection band in which a transmittance with respect to light at an incident angle of 0° becomes 50% or less, and a wavelength λLo (U1_T50%) at which a transmittance becomes 50%, on a longer wavelength side of the near-ultraviolet reflection band, is positioned on a shorter wavelength side of the wavelength λLo (DU_T50%).

Assignees

• Asahi Glass Co Ltd

Inventors

• Ooi Yoshiharu
• Shiono Kazuhiko
• Yoshioka Asana
• Suzuki Shoko
• Hotaka Hiroki

Classifications

• G02B5/223

  containing organic substances, e.g. dyes, inks or pigments · CPC title

• G02B5/281 Primary

  designed for the infrared light · CPC title