Optical filter
An optical filter, includes: a substrate, a dielectric multilayer film 1 laid on or above one major surface of the substrate, and a dielectric multilayer film 2 laid on or above the other major surface of the substrate, in which the substrate includes a near infrared ray absorbing glass and a resin film, the resin film includes a resin and a pigment (NIR1), and the optical filter satisfies all of spectral characteristics (i-1) to (i-3), (i-6) to (i-8), and (i-10) to (i-13).
1 . An optical filter, comprising:
a substrate,
a dielectric multilayer film 1 laid on or above one major surface of the substrate, and
a dielectric multilayer film 2 laid on or above the other major surface of the substrate, wherein
the substrate comprises a near infrared ray absorbing glass and a resin film,
the resin film has a thickness of 10 μm or less,
the resin film comprises a resin and a pigment (NIR1), and
the optical filter satisfies all of the following spectral characteristics (i-1) to (i-3), and (i-6) to (i-8):
(i-1) in a spectral transmittance curve at an incident angle of 0 degrees, an average transmittance T 450-600(0deg)AVE at a wavelength of 450 nm to 600 nm is 80% or more,
(i-2) in a spectral transmittance curve at an incident angle of 50 degrees, an average transmittance T 450-600(50deg)AVE at the wavelength of 450 nm to 600 nm is 80% or more,
(i-3) an absolute value of a difference between the average transmittance T 450-600(0deg)AVE and the average transmittance T 450-600(50deg)AVE is 5% or less,
(i-6) in the spectral transmittance curve at an incident angle of 0 degrees, a maximum transmittance T 450-600(0deg)MAX at the wavelength of 450 nm to 600 nm is 90% or more,
(i-7) in the spectral transmittance curve at an incident angle of 0 degrees, a wavelength IR50 (0deg) at which a transmittance is 50% is in a range of 610 nm to 650 nm, and
(i-8) in the spectral transmittance curve at an incident angle of 50 degrees, a wavelength IR50 (50deg) at which a transmittance is 50% is in the range of 610 nm to 650 nm, and
the optical filter satisfies the following spectral characteristics:
in the spectral transmittance curve at an incident angle of 0 degrees, a maximum transmittance at a wavelength of 750 nm to 1000 nm is 2.6% or less, and
in the spectral transmittance curve at an incident angle of 50 degrees, a maximum transmittance at a wavelength of 750 nm to 1000 nm is 3% or less.
2 . The optical filter according to claim 1 , further satisfying the following spectral characteristic:
in the spectral transmittance curve at an incident angle of 0 degrees, the maximum transmittance T 450-600(0deg)MAX at the wavelength of 450 nm to 600 nm is 93% or more.
3 . The optical filter according to claim 1 , further satisfying the following spectral characteristic:
in the spectral transmittance curve at an incident angle of 50 degrees, the maximum transmittance at a wavelength of 750 nm to 1000 nm is 2.1% or less.
4 . The optical filter according to claim 1 , further satisfying the following spectral characteristics (i-4) and (i-5):
(i-4) in the spectral transmittance curve at an incident angle of 0 degrees, a transmittance T 450(0deg) at a wavelength of 450 nm is 80% or more, and
(i-5) in the spectral transmittance curve at an incident angle of 50 degrees, a transmittance T 450(50deg) at the wavelength of 450 nm is 80% or more.
5 . The optical filter according to claim 1 , further satisfying the following spectral characteristic:
in the spectral transmittance curve at an incident angle of 0 degrees, a transmittance T 450(0deg) at a wavelength of 450 nm is 85% or more.
6 . The optical filter according to claim 1 , further satisfying the following spectral characteristics (i-19) and (i-20):
(i-19) in the spectral transmittance curve at an incident angle of 0 degrees, an average transmittance T 370-400(0deg)AVE at a wavelength of 370 nm to 400 nm is 2% or less, and
(i-20) in the spectral transmittance curve at an incident angle of 50 degrees, an average transmittance T 370-400(50deg)AVE at a wavelength of 370 nm to 400 nm is 2% or less.
7 . The optical filter according to claim 1 , further satisfying the following spectral characteristic:
in the spectral transmittance curve at an incident angle of 0 degrees, an average transmittance at a wavelength of 750 nm to 1000 nm is 0.4% or less.
8 . The optical filter according to claim 1 , further satisfying the following spectral characteristic:
in the spectral transmittance curve at an incident angle of 50 degrees, an average transmittance at a wavelength of 750 nm to 1000 nm is 0.2% or less.
9 . The optical filter according to claim 1 , wherein the near infrared ray absorbing glass satisfies all of the following spectral characteristics (iii-1) and (iii-2):
(iii-1) an average internal transmittance T 450-600AVE at the wavelength of 450 nm to 600 nm is 90% or more, and
(iii-2) an internal transmittance T 450 at the wavelength of 450 nm is 92% or more.
10 . The optical filter according to claim 1 , wherein the near infrared ray absorbing glass satisfies all of the following spectral characteristics (iii-3) and (iii-4):
(iii-3) a wavelength IR50 at which an internal transmittance is 50% is in a range of 625 nm to 650 nm, and
(iii-4) an average internal transmittance T 750-1000AVE at a wavelength of 750 nm to 1,000 nm is 2.5% or less.
11 . The optical filter according to claim 1 , wherein the near infrared ray absorbing glass satisfies all of the following spectral characteristics (iii-5) and (iii-6):
(iii-5) a maximum internal transmittance T 1000-1200MAX at the wavelength of 1,000 nm to 1,200 nm is 5% or less, and
(iii-6) the internal transmittance T 450 /the maximum internal transmittance T 1000-1200MAX ≥10.
12 . The optical filter according to claim 1 , wherein the resin film satisfies all of the following spectral characteristics (iv-1) to (iv-3):
(iv-1) an average internal transmittance T 450-600AVE at the wavelength of 450 nm to 600 nm is 93% or more,
(iv-2) a maximum internal transmittance T 450-600MAX at the wavelength of 450 nm to 600 nm is 95% or more, and
(iv-3) an internal transmittance T 450 at the wavelength of 450 nm is 86% or more.
13 . The optical filter according to claim 1 , wherein the resin film satisfies all of the following spectral characteristics (iv-4) and (iv-5):
(iv-4) IR50 (L) −IR50 (S) ≥90 nm where IR50 (S) is a shortest wavelength and IR50 (L) is a longest wavelength at which an internal transmittance is 50% in a spectral transmittance curve at a wavelength of 650 nm to 900 nm, and
(iv-5) a minimum internal transmittance T 700-800MIN at a wavelength of 700 nm to 800 nm is 10% or less.
14 . The optical filter according to claim 1 , wherein the resin film comprises a squarylium compound as the pigment (NIR1), and
the resin film further comprises at least one of a squarylium compound and a cyanine compound as a pigment (NIR2) having a maximum absorption wavelength in the resin longer than the maximum absorption wavelength of the pigment (NIR1) in the resin by 20 nm to 60 nm.
15 . The optical filter according to claim 1 , wherein the resin film is provided by one layer or two layers.
16 . An imaging device comprising the optical filter according to claim 1 .