US 11,962,118 B2
Ultraviolet filter for ring laser gyroscope mirrors
Randy Ramberg, Roseville, MN (US); Lance Vrieze, Oakdale, MN (US); Steven C. Albers, Coon Rapids, MN (US); and Dean Eivind Johnson, Orono, MN (US)
Assigned to Honeywell International Inc., Charlotte, NC (US)
Filed by Honeywell International Inc., Charlotte, NC (US)
Filed on Oct. 27, 2020, as Appl. No. 17/081,764.
Prior Publication US 2022/0131333 A1, Apr. 28, 2022
Int. Cl. H01S 3/08 (2023.01); G01C 19/66 (2006.01); G02B 1/02 (2006.01); G02B 5/08 (2006.01); G02B 5/28 (2006.01); H01S 3/083 (2006.01)
CPC H01S 3/08059 (2013.01) [G01C 19/661 (2013.01); G02B 1/02 (2013.01); G02B 5/0816 (2013.01); G02B 5/283 (2013.01); H01S 3/083 (2013.01)] 16 Claims
OG exemplary drawing
 
1. A multilayer mirror, comprising:
a reflector section comprising a plurality of alternating layers of a high refractive index optical material and a low refractive index optical material, wherein each layer of the plurality of alternating layers has an optical thickness; and
a filter section over the reflector section, the filter section comprising:
a first filter layer comprising a low refractive index optical material on a layer of high refractive index optical material of the reflector section;
a second filter layer on the first filter layer, the second filter layer comprising a high refractive index optical material that is different than the high refractive index optical material in the reflector section; and
a third filter layer on the second filter layer, the third filter layer comprising a low refractive index optical material;
wherein each of the first filter layer, the second filter layer, and the third filter layer has an optical thickness that is greater than or equal to the optical thickness of each layer of the plurality of alternating layers;
wherein the optical thickness of the first filter layer is a half-wave, the optical thickness of the second filter layer is a full-wave, and the optical thickness of the third filter layer is a half-wave;
wherein the filter section substantially blocks ultraviolet (UV) energy, thereby preventing UV energy from substantially impinging on the high refractive index optical material of the reflector section.