Optical element and imaging apparatus including the same
View Patent ↗A lens includes a first optical surface including an optical axis X, and a first cut end surface at an outer circumference of the first optical surface. The first optical surface has a first SWS configured to reduce reflection of light. The first cut end surface has a second SWS configured to reduce reflection of light. A reflectance of the second SWS with respect to light having a predetermined wavelength is higher than the reflectance of the first SWS with respect to the light having the predetermined wavelength.
1. An optical element comprising:
an optical functional surface including an optical axis; and
a cut end surface at an outer circumference of the optical functional surface, wherein:
the optical functional surface has a first antireflection structure configured to reduce reflection of light,
the cut end surface has a second antireflection structure configured to reduce reflection of light,
a reflectance of the second antireflection structure with respect to light having a predetermined wavelength is higher than a reflectance of the first antireflection structure with respect to light having the predetermined wavelength,
the second antireflection structure includes a plurality of raised portions,
a flat surface is formed at a top portion of each of the raised portions,
recessed portions are each formed by being surrounded by the raised portions,
a flat surface is formed on a bottom of each of the recessed portions, and
a distance between the flat surface of the raised portion and the flat surface of the recessed portion in a direction of the optical axis is substantially a half of the predetermined wavelength to increase the reflectance of the second antireflection structure with respect to the light having the predetermined wavelength.
2. The optical element of claim 1 , wherein
the predetermined wavelength is a wavelength out of a visible light range.
3. The optical element of claim 2 , wherein
a reflectance of the first antireflection structure with respect to visible light is lower than or equal to 1%.
4. The optical element of claim 1 , wherein
the predetermined wavelength is a wavelength in an infrared range.
5. The optical element of claim 1 , wherein
the first antireflection structure includes a plurality of first raised portions,
the second antireflection structure includes a plurality of second raised portions, and
a height of the second raised portions in a direction of the optical axis is smaller than a height of the first raised portions in the direction of the optical axis.
6. An imaging apparatus comprising:
a camera body;
an imaging element that is located in the camera body; and
an interchangeable lens that is detachable from the camera body,
wherein the interchangeable lens includes the optical element of claim 1 .