Optical displacement sensor
| DWPI Title: Optical displacement sensing apparatus e.g. optical microphone, has photodetector for detecting change in intensity of beam of lasing light from vertical-cavity surface-emitting laser and generating electrical output signal |
| Abstract: An optical displacement sensor is disclosed which uses a vertical-cavity surface-emitting laser (VCSEL) coupled to an optical cavity formed by a moveable membrane and an output mirror of the VCSEL. This arrangement renders the lasing characteristics of the VCSEL sensitive to any movement of the membrane produced by sound, vibrations, pressure changes, acceleration, etc. Some embodiments of the optical displacement sensor can further include a light-reflective diffractive lens located on the membrane or adjacent to the VCSEL to control the amount of lasing light coupled back into the VCSEL. A photodetector detects a portion of the lasing light from the VCSEL to provide an electrical output signal for the optical displacement sensor which varies with the movement of the membrane. |
| Use: Optical displacement sensing apparatus e.g. optical microphone, optical pressure sensor, optical vibration sensor and optical accelerometer. |
| Advantage: The apparatus reduces the effect of squeezed-film damping present in types of optical displacement sensors which require a membrane to be located very close to an adjacent substrate. |
| Novelty: The apparatus (10) has a membrane (12) located proximate to a vertical-cavity surface-emitting laser (VCSEL) (16) for receiving beam (26) of lasing light and to reflect a portion of the beam of lasing light back into the VCSEL through an output mirror of the VCSEL. The membrane and an output mirror are coupled to optical cavity (30) to produce a change in intensity of the beam of lasing light. A photodetector detects the change in intensity of the beam of lasing light from the VCSEL and generates an electrical output signal that varies with the displacement of the membrane. |
| Filed: 12/20/2005 |
| Application Number: US2005314335A |
| Tech ID: SD 10116.0 |
| This invention was made with Government support under Contract No. DE-NA0003525 awarded by the United States Department of Energy/National Nuclear Security Administration. The Government has certain rights in the invention. |
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