Base with low-reflection film
A base with a low-reflection film includes: a transparent base; a low-reflection film formed on a first principal surface of the transparent base; and a black printed part formed on a part of a second principal surface of the transparent base opposite to the first principal surface, in which a luminous reflectance R of the base with the low-reflection film with respect to incident light from the low-reflection film side is 2% or less in a region of the transparent base having the black printed part, and a ratio R 1 /R 2 between a luminous reflectance R 1 of a surface of the low-reflection film and a luminous reflectance R 2 at an interface of the black printed part with the transparent base is ⅙ or more.
1. A base with a low-reflection film, comprising:
a transparent base having a first principal surface and a second principal surface opposite to the first principal surface;
the low-reflection film formed on the first principal surface of the transparent base; and
a black printed part formed on an outer peripheral part of the second principal surface of the transparent base,
wherein the low-reflection film is provided on the first principal surface of the transparent base but not provided on the second principal surface of the transparent base, and the black printed part is provided on the second principal surface of the transparent base but not provided on the first principal surface of the transparent base,
the black printed part is formed from a black ink directly printed on the second principal surface of the transparent base, where the black ink is an inorganic ink comprising a ceramic fired body, or an organic ink comprising dye or pigment and an organic resin, and
a luminous reflectance R of the base with the low-reflection film with respect to incident light from the low-reflection film side is 2% or less in a region of the transparent base having the black printed part, and a ratio R 1 /R 2 between a luminous reflectance R 1 of a surface of the low-reflection film and a luminous reflectance R 2 at an interface of the black printed part with the transparent base is ⅙ or more.
2. The base with the low-reflection film according to claim 1 , wherein
the luminous reflectance R of the base with the low-reflection film is 1.2% or less.
3. The base with the low-reflection film according to claim 1 , wherein
the luminous reflectance R 1 of the surface of the low-reflection film is 1% or less.
4. The base with the low-reflection film according to claim 1 , wherein
the luminous reflectance R 2 at the interface of the black printed part with the transparent base is 0.8% or less.
5. The base with the low-reflection film according to claim 1 , wherein
the transparent base has a projecting and recessed shape on the first principal surface.
6. The base with the low-reflection film according to claim 5 , wherein
a surface roughness RMS of the projecting and recessed shape is not less than 0.01 μm and not more than 0.5 μm.
7. The base with the low-reflection film according to claim 5 , wherein
an average length RSm of a roughness curve element of the projecting and recessed shape is not less than 5 μm and not more than 30 μm.
8. The base with the low-reflection film according to claim 6 , wherein
a haze value defined by JIS K 7136 of the transparent base is not less than 1% and not more than 30%.
9. The base with the low-reflection film according to claim 1 , further comprising
an antifouling film formed on the low-reflection film and having a film thickness of not less than 2 nm and not more than 20 nm.
10. The base with the low-reflection film according to claim 1 , wherein
the low-reflection film has at least one layer made of niobium oxide or silicon nitride, and at least one layer made of silicon oxide.
11. The base with the low-reflection film according to claim 1 , wherein
the transparent base is a glass substrate.
12. The base with the low-reflection film according to claim 1 , wherein the black printed part is formed such that the black printed part is visible from the low-reflection film side.
13. The base with the low-reflection film according to claim 1 , wherein the black printed part is formed by a screen printing method using the black ink.
14. The base with the low-reflection film according to claim 1 , consisting of the transparent base which is a glass substrate, the low-reflection film, the black printed part, and optionally an antifouling layer formed on the low-reflection film.
15. The base with the low-reflection film according to claim 1 , wherein the black printed part is directly formed on the outer peripheral part of the second principal surface of the transparent base such that an entirety of a largest surface of the black printed part directly contacts the second principal surface of the transparent base.
16. The base with the low-reflection film according to claim 1 , wherein the black ink is an inorganic ink comprising a ceramic fired body selected from the group consisting of an oxide, a carbide, carbon black, and mica.