US 12,069,432 B2
Optical microphone substrate
Håkon Sagberg, Oslo (NO); and Jakob Vennerød, Oslo (NO)
Assigned to Sensibel AS, Oslo (NO)
Appl. No. 17/775,699
Filed by SENSIBEL AS, Oslo (NO)
PCT Filed Nov. 11, 2020, PCT No. PCT/GB2020/052867
§ 371(c)(1), (2) Date May 10, 2022,
PCT Pub. No. WO2021/094747, PCT Pub. Date May 20, 2021.
Claims priority of application No. 1916380 (GB), filed on Nov. 11, 2019.
Prior Publication US 2022/0408198 A1, Dec. 22, 2022
Int. Cl. H04R 23/00 (2006.01); G01B 11/14 (2006.01); G01D 5/26 (2006.01)
CPC H04R 23/008 (2013.01) [G01B 11/14 (2013.01); G01D 5/266 (2013.01)] 20 Claims
OG exemplary drawing
 
1. An optical microphone assembly comprising:
a substrate;
an interferometric arrangement, the interferometric arrangement comprising a membrane and at least one diffractive optical element spaced from the membrane, wherein the at least one diffractive optical element comprises a plurality of lines formed in or disposed on a surface of the substrate, the plurality of lines being arranged in a first pattern, and wherein the substrate comprises one or more holes extending fully through the substrate, the one or more holes being arranged in a second pattern that is different from the first pattern; the optical microphone assembly further comprising:
a light source arranged to provide light to said interferometric arrangement such that a first portion of said light propagates along a first optical path via said interferometric arrangement and a second portion of said light propagates along a second different optical path via said interferometric arrangement, thereby giving rise to an optical path difference between the first and second optical paths which depends on a distance between the membrane and the diffractive optical element, wherein the one or more holes are positioned such that at least one of said first and second optical paths at least partly overlaps with the one or more holes; and
at least one photo detector arranged to detect at least part of an interference pattern generated by said first and second portions of light dependent on said optical path difference.