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US 8,711,186 B2Granted
Scanning projection apparatus with tangential compensation
AssigneeMicrovision, Inc.
InventorMark Champion
Life of this patent
Estimating the term…
Abstract
A scanning projector includes a scanning mirror that sweep a beam in two dimensions. Tangential distortion in a fast-scan dimension is compensated by incorporating a tangent function when determining the light beam location and interpolating pixel data. Tangential distortion in a slow-scan dimension is compensated by driving the scanning mirror nonlinearly in the slow scan dimension such that the light beam sweeps across the display surface at a constant rate.
Claims6
An apparatus comprising:
- a laser light source;
- a mirror being oscillatable on a first axis, the mirror being positioned to reflect light from the laser light source and sweep a light beam sinusoidally through an angle and across a display surface in a first dimension, resulting in tangential distortion in the light beam location on the display surface as a function of time;
- and
- a beam position determination component that determines a location of the light beam on the display surface, wherein the beam position determination component determines the beam location as a function of the sinusoidal sweep as well as the tangential distortion, and wherein the beam position determination component determines the pixel location as:
- x
- =
- HRES
- 2
-
- tan
-
- (
- A
-
-
- sin
-
- (
- ω
-
-
- t
- )
- )
- tan
-
- (
- A
- )
- +
- HRES
- 2
- .
30 more elements
An apparatus comprising:
- a laser light source;
- a mirror being oscillatable on a first axis, the mirror being positioned to reflect light from the laser light source and sweep a light beam sinusoidally through an angle and across a display surface in a first dimension, resulting in tangential distortion in the light beam location on the display surface as a function of time;
- and
- a beam position determination component that determines a location of the light beam on the display surface, wherein the beam position determination component determines the beam location as a function of the sinusoidal sweep as well as the tangential distortion, and wherein the pixel location determination component determines the pixel location as an approximation of:
- x
- =
- HRES
- 2
-
- tan
-
- (
- A
-
-
- sin
-
- (
- ω
-
-
- t
- )
- )
- tan
-
- (
- A
- )
- +
- HRES
- 2
- .
30 more elements
An apparatus comprising:
- a laser light source;
- a mirror being movable on two axes, the mirror being positioned to reflect light from the laser light source and onto a display surface, to sweep a light beam sinusoidally in a first dimension responsive to mirror movement on a first axis of the two axes, and to sweep the light beam nonsinusoidally in a second dimension responsive to movement on a second axis of the two axes;
- a control loop responsive to a position of the mirror on the second axis, the control loop including a feedback circuit to determine harmonic coefficients to drive mirror movement on the second axis to sweep the light beam linearly with time across the display surface in the second dimension;
- and
- a light beam position determination component that determines a location of the light beam in the first dimension on the display surface, wherein the light beam position determination component determines the beam location as a function of the sinusoidal sweep as well as a tangential error resulting from the sinusoidally swept light beam illuminating a flat surface, and wherein the light beam position determination component determines the location of the light beam in the first dimension as:
- x
- =
- HRES
- 2
-
- tan
-
- (
- A
-
-
- sin
-
- (
- ω
-
-
- t
- )
- )
- tan
-
- (
- A
- )
- +
- HRES
- 2
- .
31 more elements
An apparatus comprising:
- a laser light source;
- a mirror being movable on two axes, the mirror being positioned to reflect light from the laser light source and onto a display surface, to sweep a light beam sinusoidally in a first dimension responsive to mirror movement on a first axis of the two axes, and to sweep the light beam nonsinusoidally in a second dimension responsive to movement on a second axis of the two axes;
- a control loop responsive to a position of the mirror on the second axis, the control loop including a feedback circuit to determine harmonic coefficients to drive mirror movement on the second axis to sweep the light beam linearly with time across the display surface in the second dimension;
- and
- a light beam position determination component that determines a location of the light beam in the first dimension on the display surface, wherein the light beam position determination component determines the beam location as a function of the sinusoidal sweep as well as a tangential error resulting from the sinusoidally swept light beam illuminating a flat surface, and wherein the light beam position determination component determines the location of the light beam in the first dimension as:
- x
- =
- HRES
- 2
-
- tan
-
- (
- A
- )
-
- [
- A
-
-
- sin
-
-
- (
- ω
-
-
- t
- )
- +
- A
- 3
-
- sin
- 3
-
- (
- ω
-
-
- t
- )
- 3
- ]
- +
- HRES
- 2
- .
45 more elements
A method comprising:
- oscillating a mirror on a first axis to sweep a light beam in a first dimension on a display surface resulting in a sinusoidal sweep of the light beam with tangential distortion in the light beam location on the display surface as a function of time;
- determining a display pixel location on the display surface as a function of the sinusoidal sweep and the tangential distortion in the first dimension;
- interpolating source pixel data to arrive at display pixel data to display at the display pixel location;
- and
- commanding a laser light source to produce light in accordance with the display pixel data, wherein determining a display pixel location is an approximation of:
- x
- =
- HRES
- 2
-
- tan
-
- (
- A
-
-
- sin
-
- (
- ω
-
-
- t
- )
- )
- tan
-
- (
- A
- )
- +
- HRES
- 2
- .
31 more elements
Dependencies are inferred from the claim text.