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US 9,693,029 B1Granted
System and method for feedback control in scanning projectors
AssigneeMicrovision, Inc.
InventorRobert James Jackson
Life of this patent
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Abstract
A scanning projector and method is provided that generates a feedback signal from at least one photodetector. In the scanning projector, a scanning mirror is configured to reflect laser light into an image region and an over scanned region. The at least one photodetector is configured to receive a portion of the reflected laser light impacting the over scanned region, and provides the feedback signal responsive to the received portion of light. This feedback signal can then be used to provide precise control of the scanning mirror.
Claims19
A scanning laser projector, comprising:
- at least one source of laser light;
- a scanning mirror configured to reflect the laser light;
- a perimeter defining an image region inside the perimeter and an over scanned region outside the perimeter, the image region and over scanned region configured to receive the reflected laser light, wherein the perimeter is defined by an opening surrounded by a border fixture, where the opening resides in a virtual plane through which the reflected laser light in the image region passes;
- a photodetector configured to receive a portion of the reflected laser light impacting the over scanned region outside the perimeter, the photodetector further configured to provide a feedback signal responsive to the portion of the reflected laser light received by the photodetector;
- and
- a drive circuit configured to provide an excitation signal to excite motion of the scanning mirror, the drive circuit configured to modify the excitation signal in response to the feedback signal.
3 more elements
A method comprising:
- controlling motion of a scanning mirror to reflect laser light in a pattern across an image region inside a perimeter and across an over scanned region outside the perimeter, wherein the perimeter is defined by an opening surrounded by a border fixture, where the opening resides in a virtual plane through which the reflected laser light in the image region passes;
- detecting a portion of the reflected laser light in the over scanned region;
- providing a feedback signal responsive to the detected portion of the reflected laser light;
- and
- modifying the motion of the scanning mirror in response to the feedback signal.
2 more elements
A scanning laser projector, comprising:
- at least one source of laser light;
- a first scanning mirror configured to reflect the laser light along a first axis;
- a second scanning mirror configured to reflect the laser light along a second axis;
- a perimeter defining an image region inside the perimeter and an over scanned region outside the perimeter, the image region and over scanned region configured to receive the reflected laser light, wherein the perimeter is defined by an opening surrounded by a border fixture, where the opening resides in a virtual plane through which the reflected laser light in the image region passes;
- a photodetector configured to receive a portion of the reflected laser light impacting the over scanned region outside the perimeter, the photodetector further configured to provide a feedback signal responsive to the portion of the reflected laser light received by the photodetector;
- and
- a drive circuit configured to provide a first excitation signal to excite motion of the first scanning mirror and a second excitation signal to excite motion of the second scanning mirror, the drive circuit configured to modify the first excitation signal in response to the feedback signal to control a horizontal scan amplitude, the drive circuit further configured to modify the second excitation signal in response to the feedback signal to control a vertical scan amplitude.
4 more elements
Dependencies are inferred from the claim text.