Patent ID: 8138479
Filing Date: 2012-03-20
Classification: G06F,H05B,Y02B,Y10T

Abstract:
1. A lighting device, comprising: a first light guide having a first edge, a second edge opposite to the first edge, a planar first surface extending between the first edge and the second edge, and a planar second surface opposite to the first surface; at least one light gathering feature disposed on the first surface and configured to couple light incident on the first surface of the first light guide into the first light guide; a first light detector disposed along the first edge of the first light guide and coupled to the first light guide to receive light propagating therein, the first light detector configured to produce a first signal based on an amount of light received from the first light guide through the first edge; and a second light detector disposed along the second edge of the first light guide and coupled to the first light guide to receive light propagating therein, the second light detector configured to produce a second signal based on an amount of light received from the first light guide through the second edge, wherein the first light detector and the second light detector are electrically connected and configured to produce a control signal indicating a direction of movement of an object relative to the first edge and the second edge based at least in part on the first signal and the second signal.