Optical element and optical apparatus
An optical element including a glass body is provided. The optical element includes a colored layer provided inside the glass body and positioned outside an effective aperture of the optical element. Coloring of the colored layer is a reduction pigment occurring in a glass component of the glass body. The colored layer suppresses occurrence of stray light and obtains sufficient light-shielding properties, so that a superior image quality can be achieved.
1. An optical element including a glass body, the optical element comprising:
a colored layer provided inside the glass body and positioned outside an effective aperture of the optical element,
wherein coloring of the colored layer is a reduction pigment occurring in a glass component of the glass body.
2. The optical element according to claim 1 , wherein the colored layer is positioned from a surface of the glass body and extends inside the glass body.
3. The optical element according to claim 2 , wherein a thickness of the colored layer from the surface of the glass body and extending inside the glass body is 1 through 300 μm.
4. The optical element according to claim 1 , wherein an optical density OD of the colored layer is 2.0 or more at a wavelength of 750 nm.
5. The optical element according to claim 1 , wherein the optical element is provided with an anti-reflection coated surface and a surface without an anti-reflection coating, and
wherein the colored layer is provided at the surface without the anti-reflection coating.
6. The optical element according to claim 1 , wherein the optical element comprises a prism, including an incident surface, an exit surface, a reflection surface, and a side surface, and
wherein the colored layer is provided on the prism on at least one of the incident surface, the exit surface, the reflection surface, the side surface, and or a chamfered surface at a boundary portion defined at any one of the incident surface, the exit surface, the reflection surface, and the side surface.
7. The optical element according to claim 1 , wherein the optical element comprises a lens element, and
wherein the colored layer is provided on at least one of an edge surface and or a land surface of the lens element.
8. The optical element according to claim 1 , wherein the optical element comprises two adjacent lens elements,
wherein each of the two adjacent lens elements includes a land surface positioned radially outside the effective aperture of the lens element thereof, and the respective land surfaces of the two adjacent lens elements are brought into contact with each other, and
wherein colored layers are respectively provided on the land surfaces.
9. The optical element according to claim 1 , wherein the optical element comprises a lens element, and
wherein the colored layer defines the effective aperture on at least one surface of the lens element.
10. The optical element according to claim 1 , wherein the optical element comprises a lens element, and
wherein the colored layer is provided at mutually different colored regions, outside the effective aperture, on first and second surfaces of the lens element.
11. The optical element according to claim 1 , wherein the optical element comprises a plurality of lens surfaces, and
wherein the colored layer is provided outside effective apertures of the plurality of lens surfaces, respectively, to thereby partition the plurality of lens surfaces.
12. The optical element according to claim 1 , wherein the optical element comprises an exit window, from which light that is emitted from a light emitter exits, and an incident window, to which light travelling toward a light receiver is incident, and
wherein the colored layer is provided outside an effective aperture of the exit window and outside an effective aperture of the incident window so that the colored layer partitions the exit window and the incident window.
13. The optical element according to claim 1 , wherein the optical element comprises at least one of a flat parallel plate, a cover glass, an optical filter, or a beam splitter, and
wherein the colored layer is provided outside an effective aperture of the at least one of the flat parallel plate, the cover glass, the optical filter, or the beam splitter.
14. An optical apparatus comprising the optical element of claim 1 .
15. The optical element according to claim 1 , wherein a refractive index of the colored layer is same as a refractive index of the glass body.
16. The optical element according to claim 1 , wherein the glass component comprises at least one ion selected from the group consisting of Ti-ion, Nb-ion, W-ion, and Bi-ion.
17. The optical element according to claim 1 , wherein spectral transmittance of the colored layer from a visible light region to an infra-red region shows a tendency to increase as the wavelength increases.
18. The optical element according to claim 1 , wherein a refractive index of the glass body is 1.70 or more.