1. Technical Field of the Invention
This invention is directed to apparatus for relaying an optical beam from an unprotected environment into a protected environment for all types of optical remote control devices, including security devices and systems.
2. Description of the Prior Art
In my prior U.S. Pat. No. 4,573,046, the entire disclosure of which is hereby incorporated by reference, there is disclosed an apparatus and method for a universal electronic locking system. The system relies upon a signal transmitting unit contained within a watch which is capable of storing a plurality of codes in its memory and transmitting any one of the stored codes as an encoded optical signal to a signal receiving unit. The signal receiving unit contains a photodetector for receiving the optical signal and transforming it into an electrical signal which can be interpreted by a processor to determine whether it corresponds to a valid code stored in the memory of the signal receiving unit. If so, the signal receiving unit issues an activation signal which unlatches a lock.
As further described in the patent, the optical signal is received at the signal receiving unit by a photodetector which is recessed in a hollow area behind a transparent window. The hollow area is preferably a tubular cavity which is covered with an optically absorbing material which absorbs ambient light which enters through the window.