Scanning Mirror Control with Slow Scan Position Offset
AssigneeMicrovision, Inc.
InventorsJonathan A. Morarity, Damon M. Domjan
Life of this patent
Estimating the term…
Abstract
A scanning mirror resonates on a first axis and moves on a second axis at a frequency dictated by a sync signal. The period of movement on the second axis is not necessarily an integer multiple of the period of movement on the first axis. A drive circuit excites movement of the mirror. The drive circuit adds a position offset to the signal that excites movement on the second axis. The position offset is capable of causing the resonant movement on the first axis to scan a substantially identical trajectory for at least a portion of each period on the second axis.
Claims29
An apparatus comprising:
- a first scanning mirror capable of resonant motion on a fast-scan axis;
- a second scanning mirror capable of non-resonant motion on a slow-scan axis;
- and
- a control system to excite the first scanning mirror to move on the fast-scan axis at a resonant frequency of the first scanning mirror, and to produce a slow-scan drive signal to cause the second scanning mirror to move on the slow-scan axis at a frequency dictated by a received sync signal;
- wherein the control system adds a position offset into the slow-scan drive signal for each period of the received sync signal to cause the first and second scanning mirrors to scan a substantially identical trajectory for at least a portion of each period of the received sync signal.
An apparatus comprising:
- a signal source to provide a sync signal;
- a first scanning mirror capable of resonant movement on a first axis;
- a second scanning mirror capable of non-resonant movement on a second axis;
- and
- a scanning mirror drive circuit to excite the resonant movement on the first axis, and to cause the non-resonant movement on the second axis to be phase locked to the sync signal, wherein the scanning mirror drive circuit is configured to add a position offset on the second axis for each period of the non-resonant movement to compensate for a non-integer relationship between a period of the sync signal and a period of the resonant movement.
The apparatus of 11 wherein movement on the slow-scan axis includes an active region and a flyback region, and the position offset is added at en end of the active video region and before the flyback region.
An apparatus comprising:
- a first scanning mirror capable of resonant movement on a first axis;
- a second scanning mirror capable of non-resonant movement on a second axis;
- and
- a slow-scan offset control circuit to track a residual phase on the first axis and to add a position offset to the non-resonant movement on the second axis, the position offset being a function of the residual phase.
A method comprising:
- exciting a first scanning mirror to cause resonant movement on a first axis, the resonant movement having a first period;
- and
- exciting a second scanning mirror to cause non-resonant movement on a second axis, the non-resonant movement having a second period that is a non-integer multiple of the first period, which if not accounted for results in the resonant movement on the first axis scanning different trajectories for each second period;
- wherein exciting the second scanning mirror to cause non-resonant movement on a second axis comprises adding a position offset each second period to cause the resonant movement on the first axis to scan a substantially identical trajectory for at least a portion of each second period.
Dependencies are inferred from the claim text.