| 摘要 |
An improved light transceiver device for use in alarm or counting systems. The transceiver is housed in a light tight housing and includes an adjustable mirror offset from the active element of the transceiver. The mirror directs light through an aperture in the housing along a predetermined axis from the active element and directs light to the active element which is received through the aperture along the axis. The mirror deflects any light received through the aperture which is received at an angle greater than a predetermined angle from the axis around the active element of the transceiver to block ambient light interference. The transceiver also may be utilized in an improved light screen or barrier which may be utilized either for an alarm system such as in a jewelry case or in a counting system wherein objects are passed through the light screen in the frame to be counted.
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