US 12,328,548 B2
Optical microphone substrate
Håkon Sagberg, Oslo (NO); and Jakob Vennerød, Oslo (NO)
Assigned to SENSIBEL AS, Oslo (NO)
Filed by SENSIBEL AS, Oslo (NO)
Filed on Jul. 16, 2024, as Appl. No. 18/774,567.
Application 18/774,567 is a continuation of application No. 17/775,699, granted, now 12,069,432, previously published as PCT/GB2020/052867, filed on Nov. 11, 2020.
Claims priority of application No. 1916380 (GB), filed on Nov. 11, 2019.
Prior Publication US 2024/0373171 A1, Nov. 7, 2024
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 comprising a first substrate portion and a second substrate portion, wherein the first substrate portion is thinner than the second substrate portion;
an interferometic arrangement, the interferometric arrangement comprising a membrane and at least one optical element spaced from the membrane, wherein the at least one optical element comprises a surface of the first substrate portion and/or is disposed on a surface of the first substrate portion, and wherein the at least one optical element does not comprise a diffractive optical element that is formed as a plurality of holes through the first substrate portion, 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 optical element, wherein at least one of the first and second paths passes through the first substrate portion; 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.