| 摘要 |
A vertical cavity surface emitting laser (VCSEL) operable as a signal emitter and a silicon photodetector adapted for receiving light signals co-mounted in a common canister. Also containable is a four lead header and an isolating ceramic spacer. The canister can be electrically connected to a first lead from the header. The isolating ceramic spacer is adapted for mounting of the VCSEL above the level of the photodetector within the can. The VCSEL is electrically connectable to a second and third lead from the header and the photodetector is electrically connectable to the second and a fourth lead from the header. Co-packaging of a VCSEL and photodetector in common device canisters can yield about a 20:1 contrast ratio between an object's presence in front of the sensing system. A small pattern necessary for high accuracy is provided by the system and no barrier is necessary between the emitter and detector.
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