Acoustoelectric transducer using optical device

Abstract

An optical acoustoelectric transducer receives light reflected by a vibrating board and detects the displacement of the vibrating board. A surface-emitting luminescent device having a substantially uniform concentric intensity distribution of light emission is placed in the center of a common substrate. A photodetector element is provided to surround the luminescent device. A lens is also provided in the optical path between the substrate and the vibrating board to converge the light traveling toward and from the vibrating board.

Description

technical field [0001] The invention relates to an optical-acoustic-electric transducer that converts the vibration displacement of a vibrating plate into an electrical signal by using an optical device. In particular, the present invention provides an efficient technique employed in the case of using a vertical cavity surface emitting laser (VCSEL) as a light emitting device. Background technique [0002] So far, various types of optical acoustoelectric transducers employing optical devices have been developed and realized. For example, Japanese Patent Application Laid-Open No. 8-297011 discloses an optical fiber sensor using a pair of optical fibers, which has a structure in which light is irradiated from one optical fiber connected to a light source to a vibrating medium, and is transmitted by Another fiber detects this light, indicating that it is intended for a microphone. In addition, US Patent No. 6,055,080 also discloses a structure of an optical microphone using a...

AI Technical Summary

Problems solved by technology

For this reason, there is a problem that if a light emitting device, a photodetection unit, a vibrating plate, etc. are formed using separate parts, the yield will decrease because it is difficult to achieve high-precision alignment in the process of manufacturing the product

[0013] However, if the structure of the head of the optical microphone is to be miniaturized, it has always been difficult to mount the light emitting device and the photodetection unit on the substrate at a predetermined angle because the parts including the head are different, and furthermore, it has always been difficult to Adjust the angle of incidence and reflection

[0014] In addition, it takes a lot of man-hours to mount the light-emitting device and the photodetection unit on the substrate at a predetermined angle, not only that, but also a very difficult task to adjust the focus of the reflected light to be accurately aligned with the light-receiving surface of the photodetection unit

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