Microphone component and method of manufacture

A method of manufacturing an optical microphone module for installation in a housing to form an optical microphone assembly, wherein the optical microphone module comprises:

• an interferometric component comprising a substrate, a membrane and at least one optical element spaced from the membrane, wherein i) the at least one optical element comprises a surface of the substrate, or ii) the at least one optical element is disposed on the surface of the substrate, or iii) the at least one optical element comprises e the surface of the substrate and is disposed on the surface of the substrate:
• a semiconductor chip comprising at least one photo detector and a light source, wherein the at least one photo detector and the light source are mounted on or integrated in the semiconductor chip:
• a spacer;
• and
• one or more optical components provided in or on the spacer:
• the method comprising:
• assembling the semiconductor chip, the spacer and the interferometric component in a stack with the spacer disposed between the semiconductor chip and the interferometric component:
• wherein the light source and the at least one photo detector have respective positions on the semiconductor chip such that after the semiconductor chip, the spacer and the interferometric component have been assembled in the stack, the light source is disposed to provide light to the interferometric component such that a first portion of said light propagates along a first optical path via said interferometric component and a second portion of said light propagates along a second optical path via said interferometric component, wherein the second optical path is different from the first optical path, thereby giving rise to an optical path difference between the first optical path and the second optical path which depends on a distance between the membrane and the at least one optical element, and the at least one photo detector is disposed to detect at least part of an interference pattern generated by said first and second portions of light dependent on said optical path difference:
• wherein the stack comprises an internal cavity and at least one aperture providing a passage for air between the internal cavity and an exterior of the stack, such that the internal cavity is in fluid communication with the exterior of the stack;
• and
• wherein a first side of the membrane is in fluid communication with the exterior of the stack and a second side of the membrane is in fluid communication with the internal cavity.

An optical microphone module for installation in a housing to form an optical microphone assembly, the optical microphone module comprising:

• an interferometric component comprising a substrate, a membrane and at least one optical element spaced from the membrane, wherein i) the at least one optical element comprises a surface of the substrate, or ii) the at least one optical element is disposed on the surface of the substrate, or iii) the at least one optical element comprises the surface of the substrate and is disposed on the surface of the substrate:
• a semiconductor chip comprising an optoelectronic circuit including at least one photo detector:
• a light source mounted on the semiconductor chip or integrated with the optoelectronic circuit and the at least one photo detector in the semiconductor chip;
• and
• a spacer:
• wherein the semiconductor chip, the spacer and the interferometric component are assembled in a stack with the spacer disposed between the semiconductor chip and the interferometric component:
• wherein the light source is arranged to provide light to the interferometric component such that a first portion of said light propagates along a first optical path via said interferometric component and a second portion of said light propagates along a second optical path via said interferometric component, wherein the second optical path is different from the first optical path, thereby giving rise to an optical path difference between the first optical path and the second optical path which depends on a distance between the membrane and the at least one optical element, and wherein the at least one photo detector is 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:
• wherein the stack comprises an internal cavity and at least one aperture providing a passage for air between the internal cavity and an exterior of the stack, such that the internal cavity is in fluid communication with the exterior of the stack;
• and
• wherein a first side of the membrane is in fluid communication with the exterior of the stack and a second side of the membrane is in fluid communication with the internal cavity.