US 9,809,714 B2
Antireflection coating film and antireflection coating material for optical element and optical element
Reiko Kubota, Yokohama (JP)
Assigned to Canon Kabushiki Kaisha, Tokyo (JP)
Filed on Jul. 2, 2014, as Appl. No. 14/322,790.
Application 14/322,790 is a continuation of application No. 13/578,063, granted, now 8,809,421, previously published as PCT/JP2011/053313, filed on Feb. 9, 2011.
Claims priority of application No. 2010-029513 (JP), filed on Feb. 12, 2010; and application No. 2011-002164 (JP), filed on Jan. 7, 2011.
Prior Publication US 2014/0323612 A1, Oct. 30, 2014
This patent is subject to a terminal disclaimer.
Int. Cl. C08K 7/00 (2006.01); C09D 5/00 (2006.01); C09D 7/12 (2006.01); G02B 1/111 (2015.01); C08K 3/22 (2006.01); C08K 3/34 (2006.01)
CPC C09D 5/006 (2013.01) [C09D 7/1216 (2013.01); C09D 7/1266 (2013.01); G02B 1/111 (2013.01); C08K 3/22 (2013.01); C08K 3/34 (2013.01)] 18 Claims
1. An optical coating film for an optical element, the optical coating film being formed on the surface of a substrate composed of an optical material, the optical coating film comprising:
first particles at least having a refractive index (nd) of 2.2 to 3.5 for the d-line and an average particle size of 10 nm to 70 nm;
second particles composed of at least one of silica and sericite,
a colorant; and
a resin,
wherein a first particle content with respect to the optical coating film is in the range of 10% by weight to 35% by weight, and a second particle content with respect to the optical coating film is in the range of 1% by weight to 11% by weight,
wherein the optical coating film is a light-shielding coating film, and
wherein a ratio of the minimum absorbance to the maximum absorbance (minimum absorbance/maximum absorbance) of the optical coating film for the optical element in the wavelength range of 400 nm to 700 nm is 0.7 or more.