Light-shielding film for optical element and optical element having light-shielding film
A light-shielding film for optical element includes at least a resin and a colorant. The light-shielding film for optical element has an average extinction coefficient of 0.03 or more and 0.15 or less as an average of extinction coefficients of the whole light-shielding film for light having wavelengths ranging from 400 to 700 nm.
1. An optical element comprising a lens or a prism, having a light-shielding film on an outer portion,
wherein the light-shielding film for the optical element has an average thickness of 2 μm or more and 30 μm or less,
wherein the light-shielding film comprise a resin, a colorant and (i) non-black particles having an average particle diameter of 100 nm or less and a refractive index (nd) of 2.2 or more or (ii) inorganic black particles having an average particle diameter of 100 nm or less and a refractive index (nd) of 2.2 or more and 3.5 or less, and
wherein the average of extinction coefficient of the whole light-shielding film for light having wavelengths ranging from 400 to 700 nm is 0.03 or more and 0.15 or less.
2. The optical element according to claim 1 ,
wherein an inner-surface reflectance of inner-surface-reflected light, which is incident light having entered from the side of the optical element and having been reflected at an interface between the optical element and the light-shielding film and at an interface between the light-shielding film and air, at an incident angle of 36.73° is 0.05% or less, the inner-surface reflectance at an incident angle of 45° is 0.07% or less, and the inner-surface reflectance at an incident angle of 68.13° is 1% or less.
3. The optical element according to claim 1 ,
wherein the colorant contains 20 wt % or more and 50 wt % or less of dye.
4. The optical element according to claim 1 ,
wherein the light-shielding film comprises dye and the non-black particles.
5. The optical element according to claim 4 ,
wherein the non-black particles are titania, zirconia, or a mixture thereof.
6. The optical element according to claim 1 ,
wherein the colorant is dye.
7. An optical element comprising a lens or a prism, having a light-shielding film on an outer portion,
wherein the light-shielding film for the optical element has an average thickness of 2 μm or more and 30 μm or less,
wherein the light-shielding film comprise a resin, a colorant and non-black particles having an average particle diameter of 100 nm or less and a refractive index (nd) of 2.2 or more,
wherein the average of extinction coefficient of the whole light-shielding film for light having wavelengths ranging from 400 to 700 nm is 0.03 or more and 0.15 or less, and
wherein an inner-surface reflectance of inner-surface-reflected light, which is incident light having entered from the side of the optical element and having been reflected at an interface between the optical element and the light-shielding film and at an interface between the light-shielding film and air, at an incident angle of 36.73° is 0.05% or less, the inner-surface reflectance at an incident angle of 45° is 0.07% or less, and the inner-surface reflectance at an incident angle of 68.13° is 1% or less.