Pulse coded sound reproduction using optical read-out of the microphone membrane

Claim 2

A structure for providing pulse coded electric reproduction of the displacement of a body with respect to a fixed reference frame, said structure comprising i. an electrically controlled emitter of a sequence of radiation pulses, ii. a zone plate lens to direct some of said radiation pulses on a photoelectric sensor, transferring incident said radiation pulses into electrical pulse signals, iii. part of the optical system comprising said emitter of radiation pulses, said zone plate lens and said sensor attached to said fixed reference frame and another part attached to said body, iv. the principal ray of said optical system oriented substantially in direction of said displacement, whereby the flux of said radiation pulses incident on said sensor is modified by said displacement so that the amplitude of said electrical pulse signals depends on said displacement.

Claim 3

The structure of claim 1, whereby said emitter of radiation pulses is a p-n junction semiconducting light sOurce at which voltage pulses are applied.

Claim 4

The structure of claim 2, whereby said p-n junction light source is operated in the forward bias regime.

Claim 5

The structure of claim 3, whereby said p-n junction light source is operated in the laser regime.

Claim 6

The structure of claim 1, whereby said sensor is a semiconducting device.

Claim 7

The structure of claim 5, whereby said sensor is located in the central zone of said zone plate lens.

Claim 8

The structure of claim 5, whereby said semiconducting sensor is integrated with semiconducting amplifier means.

Claim 9

The structure of claim 7, whereby said sensor and at least a portion of said amplifier means are located in the central zone of said zone plate lens.

Claim 10

An optoelectric microphone comprising (i) a vibrating membrane, (ii) a periodically pulsed electrically activated light source, (iii) a zone plate optical system which images light from said light source on an electrical sensor for said light, (iv) a portion of the arrangement comprising said light source, said sensor and said optical system attached to a fixed reference frame, and another portion attached to said vibrating membrane, (v) the principal ray of said optical sensor directed substantially perpendicular to said membrane, whereby the vibration of said membrane changes the flux of said light incident from said light source onto said sensor by shifting the image of said light source with respect to the position of said sensor, (vi) said light source operated at a frequency exceeding 1000 Hz, and at a duty cycle substantially less than unity, thereby providing a pulse-coded electrical signal from said sensor in response to said vibration of said membrane.

Claim 11

An optoelectric microphone comprising (i) a vibrating membrane, (ii) a periodically pulsed electrically activated light source, (iii) a zone plate optical system which images light from said light source on an electrical sensor for said light, (iv) a portion of the arrangement comprising said light source, said sensor and said optical system attached to a fixed reference frame, and another portion attached to said vibrating membrane, (v) the principal ray of said optical sensor directed substantially perpendicular to said membrane, whereby the vibration of said membrane changes the flux of said light incident from said light source onto said sensor by shifting the image of said light source with respect to the position of said sensor, (vi) said light source operated at a frequency exceeding 1000 Hz, and at a duty cycle substantially less than unity, thereby providing a pulse-coded electrical signal from said sensor in response to said vibration of said membrane.