Image Stabilization in a Laser-Scanning Based Projector

• US 20090079945A1
• Filed: 09/26/2007
• Published: 03/26/2009
• Est. Priority Date: 09/26/2007
• Status: Active Grant

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Yavid, Dmitriy, Klosowiak, Tomasz L., Valliath, George T.
• Granted Patent: US 7,857,460 B2
• Time in Patent Office: Days
• US Class Current: 353/69
• CPC Class Codes: G02B 27/642 Optical derotators, i.e. systems for compensating for image rotation, e.g. using rotating prisms, mirrors
• CPC Class Codes: G03B 21/28 Reflectors in projection beam in illumination beam G03B21/2066

Abstract

A projector assembly includes a multi-pixel frame projector that sequentially projects each pixel making up a frame to a viewing surface, a movement detector coupled to the projector to detect a physical movement of the projector, and a movement compensator coupled to the projector, the movement compensator operable to transmit a correction signal to the projector, the correction signal capable of causing the projector to compensate for the detected movement.

Claims

1. A projector assembly comprising:

a multi-pixel frame projector sequentially projecting each pixel making up a frame to a viewing surface;

a movement detector coupled to the projector to detect a physical movement of the projector; and

a movement compensator coupled to the projector, the movement compensator operable to transmit a correction signal to the projector, the correction signal capable of causing the projector to compensate for the detected movement.

2. The projector assembly according to claim 1, wherein the projector comprises:

a first movable mirror;

a first mirror controller communicatively coupled to the first movable mirror and to the movement compensator and adapted to control and move the first movable mirror at a first speed;

a second movable mirror; and

a second mirror controller communicatively coupled to the compensator and to the second movable mirror and adapted to control and move the second movable mirror at a second speed that is different from the first speed,

wherein the movement compensator, in response to receiving a signal from the movement detector that the projector has moved, communicates compensation signals to the first and second mirror controllers, the compensation signals capable of causing the first and second mirror controllers to compensate for the detected projector movement.

3. The projector assembly according to claim 1, wherein the projector comprises:

a first movable mirror;

a second movable mirror; and

a movable cradle securing the first and second mirrors at a fixed distance from each other and communicatively coupled to the movement compensator,

wherein the movement compensator, in response to receiving a signal from the movement detector that the projector has moved, communicates a compensation signal to the cradle, the compensation signal capable of causing the cradle to compensate for the detected projector movement.

4. The projector assembly according to claim 1, further comprising:

a distance measurement device coupled to the movement compensator for determining a distance from the projector to the viewing surface.

5. The projector assembly according to claim 1, wherein the movement detector comprises:

an inertial measurement unit.

6. The projector assembly according to claim 1, wherein the movement compensator comprises:

a comparator operable to compare a magnitude of projector movement to a movement limit value and discontinue transmission of a compensation signal if the magnitude of projector movement is greater than the movement limit value.

7. The projector assembly according to claim 1, wherein:

the correction signal causes the projector to compensate less than all of the pixels making up the frame currently being drawn.

8. The projector assembly according to claim 1, wherein:

the projector compensates for the detected movement by adjusting a timing of a light source.

9. An image stabilizer comprising:

a movement detector;

a first movable mirror;

a movement compensator communicatively coupled to the movement detector;

a first mirror controller communicatively coupled to the compensator and to the first movable mirror, the first mirror controller adapted to control and move the first movable mirror at a first speed;

a second movable mirror; and

a second mirror controller communicatively coupled to the compensator and to the second movable mirror, the second mirror controller adapted to control and move the second movable mirror at a second speed different from the first speed,

wherein the movement compensator, in response to receiving a signal from the movement detector that the projector has moved, communicates at least one compensation signal to at least one of the first and second mirror controllers, the at least one compensation signal capable of causing at least one of the first and second mirror controller to compensate for the detected projector movement.

10. The image stabilizer according to claim 9, wherein:

the first and second mirrors are components of a laser projection display projector assembly.

11. The image stabilizer according to claim 9, wherein:

the first mirror is a dedicated horizontally-moving mirror; and

the second mirror is a dedicated vertically-moving mirror with a movement speed less than a movement speed of the horizontally-moving mirror.

12. The image stabilizer according to claim 9, wherein the movement detector comprises at least one of a gyroscope and an inertia sensor.

13. The image stabilizer according to claim 9, further comprising:

a plurality of lasers, each operable to output a ray of light to the first mirror.

14. The image stabilizer according to claim 9, further comprising:

a cradle physically coupled to the first and second movable mirrors and communicatively coupled to the movement compensator,

wherein the cradle, upon receiving a compensation signal from the movement compensator, moves at least one of the first and second mirrors to compensate for a detected projector movement.

15. The image stabilizer according to claim 14, wherein:

the movement compensator sends a compensation signal to at least one of the first and second mirrors to compensate for a detected physical movement when a value of the signal from the movement detector is below a predefined value and sends a compensation signal to the cradle when a value of the signal from the movement detector is above the predefined value.

16. A laser projector comprising:

a plurality of lasers, each operable to output a ray of light and each of a different color along a given ray path;

a dedicated horizontally-moving mirror disposed in the ray path;

a dedicated vertically-moving mirror disposed in the ray path;

a movement detector operable to detect translational and rotational movement of the laser housing; and

a movement compensator communicatively coupled to the movement detector and operable to calculate a compensation movement value for at least one of the horizontally-moving mirror and the vertically-moving mirror, the compensation movement value compensating for a displacement of the at least one of the horizontally-moving mirror and the vertically-moving mirror caused by the detected movement.

17. The laser projector according to claim 16, further comprising:

a first mirror controller communicatively coupled to the compensator and to the horizontally-moving mirror, the first mirror controller adapted to control and move the horizontally-moving mirror at a first speed; and

a second mirror controller communicatively coupled to the compensator and to the vertically-moving mirror, the second mirror controller adapted to control and move the vertically-moving mirror at a second speed that is different from the first speed.

18. The laser projector according to claim 17, wherein:

the movement compensator, in response to receiving a signal from the movement detector, communicates a first compensation signal to the first mirror controller and a second compensation signal to the second mirror controller, the first and second compensation signals capable of causing the first mirror controller and the second mirror controller to compensate for a detected physical movement.

19. The laser projector according to claim 16, further comprising:

a distance measurement device for determining a distance from the projector to a viewing surface communicatively coupled to the movement compensator to alter the compensation movement value dependent upon the distance measured.

20. The laser projector according to claim 16, wherein the movement compensator comprises:

a comparator operable to compare a magnitude of projector movement value to a movement limit value and discontinue transmission of a compensation signal if the magnitude of projector movement is greater than the movement limit value.