Method of directing an optical receiver toward a light source and an apparatus of practicing the method
A method and an apparatus are for directing an optical receiver toward a light source, using a plurality of light detectors arranged around the receiver's optical axis to check where light (L) hits the light detectors relative to the optical axis. The method includes the steps of: A) arranging the receiver defocused to embrace a largest possible field of view of the area wherein the light source may be located, and refracting the light with largest possible spread angle; B) letting the receiver search for the light source until the light (L) hits at least one of the light detectors; C) calculating where the light hits relative to the optical axis, and adjusting the receiver, directing the light toward the optical axis; D) reducing the field of view embraced by the receiver; and E) repeating the steps C and D until the light is concentrated in a smallest possible area.
1. A method of directing an optical receiver associated with an optical transmitter towards a light source, the method comprising the steps of:
a) providing the optical receiver with an optical system and a plurality of light detectors positioned around a primary optical axis, the light detectors being configured to receive a first light beam and to detect an intensity thereof relative to the primary optical axis which extends linearly from the light detectors through the optical system, the optical system including a pair of inner lenses movably mounted in the receiver in different x, y and z directions in response to the intensity of the first light beam on the light detectors;
b) arranging the receiver defocused such that the optical system embraces a largest possible field of view of an area where the first light beam is located, and such that the first light beam is refracted with a largest possible spread angle towards the light detectors;
c) letting the receiver search for the light source by scanning a surrounding environment until the first tight beam hits at least one of the light detectors;
d) calculating where the first light beam hits relative to the primary optical axis, and, with the current field of view, adjusting the receiver such that the first light beam is directed towards the primary optical axis;
e) reducing the field of view of the receiver by moving the pair of inner lenses independently of one another in the x, y and z directions; and
f) repeating the steps d) and e) until a minimum spread angle of the first light beam centers in the smallest possible spot on the light detectors relative to the primary optical axis,
wherein the secondary optical axis and a spread angle of the second light beam sent out from the transmitter is dependent on the directing of the primary optical axis and the field of view of the receiver.
2. The method of claim 1 , wherein the receiver and the transmitter are arranged as a transceiver.
3. The method of claim 1 , wherein the first light beam and the second light beam pass in opposite directions through the optical system and along the primary optical axis.
4. The method of claim 1 , wherein the receiver is configured to recognize a key sent from the second light beam which modulates a light with spread spectrum.
5. The method of claim 1 , wherein the steps b)-f) are repeated if differences in the intensity of the first light beam with the light detectors exceeds a predetermined level.
6. The method of claim 1 , wherein the directing of the receiver is controlled by at least one of a set of motors connected with the pair of movable inner lenses and a set of motors connected to the receiver for providing movement thereof.