Optical element and optical apparatus
Abstract
The optical element includes a base member, and a first layer which is formed on the base member and whose refractive index for a central use wavelength λ changes in a thickness direction of the first layer by 0.05 or more. The first layer has an anti-reflection function and satisfies n t =n i +0.1 (n s −n i ), 0.5≦[n{t(n t )/2}−n t ]/[n s −n{t(n t )/2}]0.8, λ/4≦t(n t )≦2λ and 1.0≦n i ≦1.1. n i represents a refractive index of a most light entrance side part of the first layer for the central use wavelength, n s represents a refractive index of a most base member side part of the first layer for the central use wavelength, t(n o ) represents an optical film thickness of the first layer at which the refractive index thereof for the central use wavelength is n o , and n{t o } represents a refractive index of the first layer for the central use wavelength at a position where the optical film thickness is t o .
Claims
exact text as granted — not AI-modifiedWhat is claimed is:
1 . An optical element comprising:
a base member; and a first layer which is formed on the base member and whose refractive index for a central use wavelength λ changes in a direction of a thickness of the first layer by 0.05 or more, wherein the first layer has an anti-reflection function and satisfies the following conditions:
n
t
=
n
i
+
0.1
·
(
n
s
-
n
i
)
0.5
≤
n
{
t
(
n
t
)
/
2
}
-
n
t
n
s
-
n
{
t
(
n
t
)
/
2
}
≤
0.8
λ
4
≤
t
(
n
t
)
≤
2
λ
1.0
≤
n
i
≤
1.1
where n i represents a refractive index of a most light entrance side part of the first layer for the central use wavelength, n s represents a refractive index of a most base member side part of the first layer for the central use wavelength, t(n o ) represents an optical film thickness of the first layer at which the refractive index thereof for the central use wavelength is n o , and n{t o } represents a refractive index of the first layer for the central use wavelength at a position where the optical film thickness is t o .
2 . The optical element according to claim 1 , wherein at least one optical interference layer is formed between the base member and the first layer.
3 . The optical element according to claim 2 , wherein a refractive index of at least one of the optical interference layer for the central use wavelength is between a refractive index of the base member and n s .
4 . The optical element according to claim 1 , wherein the refractive index of the first layer changes more gently on a light entrance side than on a base member side.
5 . The optical element according to claim 1 , wherein the first layer is formed by plural structure portions each smaller than the central use wavelength.
6 . An optical apparatus comprising:
an optical element which comprises: a base member; and a first layer which is formed on the base member and whose refractive index for a central use wavelength λ changes in a direction of a thickness of the first layer by 0.05 or more, wherein the first layer has an anti-reflection function and satisfies the following conditions:
n
t
=
n
i
+
0.1
·
(
n
s
-
n
i
)
0.5
≤
n
{
t
(
n
t
)
/
2
}
-
n
t
n
s
-
n
{
t
(
n
t
)
/
2
}
≤
0.8
λ
4
≤
t
(
n
t
)
≤
2
λ
1.0
≤
n
i
≤
1.1
where n i represents a refractive index of a most light entrance side part of the first layer for the central use wavelength, n s represents a refractive index of a most base member side part of the first layer for the central use wavelength, t(n o ) represents an optical film thickness of the first layer at which the refractive index thereof for the central use wavelength is n o , and n{t o } represents a refractive index of the first layer for the central use wavelength at a position where the optical film thickness is t o .Join the waitlist — get patent alerts
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