Large size image projection

• US 20060087628A1
• Filed: 10/27/2004
• Published: 04/27/2006
• Est. Priority Date: 10/27/2004
• Status: Active Grant

• Current Assignee: Microvision, Inc.
• Original Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Inventors: Goldman, Ron, Yavid, Dmitriy, Wood, Frederick F., Tan, Chinh, Dvorkis, Paul
• Granted Patent: US 7,441,902 B2
• Time in Patent Office: Days
• US Class Current: 353/121
• CPC Class Codes: G03B 21/208 Homogenising, shaping of the illumination light
• CPC Class Codes: G03B 35/18 by simultaneous viewing
• CPC Class Codes: G03B 37/04 with cameras or projectors providing touching or overlapping fields of view
• CPC Class Codes: H04N 9/3129 scanning a light beam on the display screen scanning a light beam on a screen in displays other than projection devices G09G3/02; scanning systems in general G02B26/10; projectors using laser light sources in general H04N9/3161

Abstract

A plurality of image projection modules is operative for causing selected pixels in overlapping raster patterns to be illuminated to produce a large size image of high resolution of VGA quality in monochrome or color. The selected pixels in an overlap region of the patterns are illuminated at a lesser intensity to provide uniform brightness over the image. Multiple single mode lasers, or a multimode laser with an aperture stop, are employed to increase laser output power. Speckle noise is reduced by controlling the optical transmission characteristic of a projection screen. Three-dimensional images are generated by moving the screen. Cross-coupling between drive and feedback mechanisms in image projection is reduced for better image quality.

Claims

1. An arrangement for projecting an image, comprising:

a) a plurality of image projection modules, each having a laser for emitting a laser beam and a scanner for sweeping a pattern of scan lines in space at a distance from the modules, each scan line having a number of pixels, each pattern being partly overlapped at an overlap region; and

b) a controller operatively connected to each laser and each scanner, for causing selected pixels to be illuminated, and rendered visible, by each laser beam to produce the image from each pattern, the selected pixels in the overlap region being illuminated at a lesser intensity than selected pixels not in the overlap region.

2. The arrangement of claim 1, wherein each laser is a solid-state laser.

3. The arrangement of claim 1, wherein each scanner includes a first oscillatable scan mirror for sweeping the laser beam along a first direction at a first scan rate and over a first scan angle, and a second oscillatable scan mirror for sweeping the laser beam along a second direction substantially perpendicular to the first direction, and at a second scan rate different from the first scan rate, and at a second scan angle different from the first scan angle.

4. The arrangement of claim 3, wherein at least one of the scan mirrors is oscillated by an inertial drive.

5. The arrangement of claim 1, wherein the controller includes means for energizing each laser to illuminate the selected pixels, and for deenergizing each laser to non-illuminate pixels other than the selected pixels.

6. The arrangement of claim 1, wherein the controller includes means for merging the scan lines from each pattern in the overlap region.

7. The arrangement of claim 1, wherein the image has a resolution which comprises at least 160 pixels in each scan line, and at least 160 scan lines in each pattern.

8. A method of projecting an image, comprising the steps of:

a) emitting a plurality of laser beams;

b) sweeping a plurality of patterns of scan lines in space, each scan line having a number of pixels, each pattern being partly overlapped at an overlap region;

c) causing selected pixels to be illuminated, and rendered visible, by each laser beam to produce the image from each pattern; and

d) illuminating the selected pixels in the overlap region at a lesser intensity than selected pixels not in the overlap region.

9. A method of creating an image from subimages, comprising the steps of:

a) emitting a plurality of laser beams;

b) sweeping a plurality of patterns of scan lines in space, each scan line having a number of pixels;

c) causing selected pixels to be illuminated, and rendered visible, by each laser beam to produce a subimage from each pattern; and

d) tiling the subimages to create the image by overlapping the patterns at an overlap region.

10. An arrangement for projecting an image, comprising:

a) a plurality of single mode lasers for emitting respective laser beams;

b) a common focusing lens for focusing the laser beams to different respective laser spots;

c) a scanner for sweeping a pattern of scan lines in space at a distance from the lasers, each scan line having a number of pixels; and

d) a controller operatively connected to each laser and the scanner, for causing selected pixels to be illuminated, and rendered visible, by the laser beams to produce the image, the controller being operative for independently energizing each laser at a different time during a predetermined frame interval at respective selected pixels.

11. A method of creating an image of high intensity, comprising:

a) a plurality of single mode lasers for emitting respective laser beams of less intensity than that of the high intensity image;

b) a common focusing lens for focusing the laser beams to different respective laser spots;

c) a scanner for sweeping a pattern of scan lines in space at a distance from the lasers, each scan line having a number of pixels; and

d) a controller operatively connected to each laser and the scanner, for causing selected pixels to be illuminated, and rendered visible, by the laser beams to produce the high intensity image, the controller being operative for independently energizing each laser at a different time during a predetermined frame interval at respective selected pixels such that the laser beams of less intensity combine to form the high intensity image.

12. An arrangement for projecting an image, comprising:

a) a single multimode laser for emitting a divergent laser beam;

b) an aperture stop for blocking parts of the divergent laser beam;

c) a scanner for sweeping a pattern of scan lines in space at a distance from the laser, each scan line having a number of pixels; and

d) a controller operatively connected to the laser and the scanner, for causing selected pixels to be illuminated, and rendered visible, by the laser beam to produce the image.

13. An arrangement for projecting an image, comprising;

a) an image projection module having a laser for emitting a laser beam, a scanner for sweeping a pattern of scan lines in space at a distance from the module, each scan line having a number of pixels, and a controller operatively connected to the laser and the scanner for causing selected pixels to be illuminated, and rendered visible, by the laser beam to produce the image; and

b) a screen on which the image is visible, the screen having an optical transmission characteristic that produces a plurality of reflections at each pixel.

14. The arrangement of claim 13, wherein the screen is a front projection screen having a total reflecting coating.

15. The arrangement of claim 13, wherein the screen is a rear projection screen having an anti-reflection coating.

16. The arrangement of claim 13, wherein the screen is movable.

17. A method of creating a three-dimensional image, comprising the steps of:

a) an image projection module having a laser for emitting a laser beam, optics for focusing the beam, a scanner for sweeping a pattern of scan lines in space at a distance from the module, each scan line having a number of pixels, and a controller operatively connected to the laser and the scanner for causing selected pixels to be illuminated, and rendered visible, by the laser beam to produce the image; and

b) a screen on which the image is visible, the screen being movable to a multitude of positions at which the laser beam is focused to create the three-dimensional image.

18. An arrangement for projecting an image, comprising:

a) a laser for emitting a laser beam;

b) a scanner including a scan mirror for reflecting the laser beam, and a drive mechanism for oscillating the scan mirror to sweep the laser beam as a pattern of scan lines in space at a distance from the laser, each scan line having a number of pixels; and

c) a controller operatively connected to the laser and the scanner for causing selected pixels to be illuminated, and rendered visible, by the laser beam to produce the image, the controller including a pick-up mechanism different from the drive mechanism for monitoring a position of the scan mirror during oscillation.

19. The arrangement of claim 18, wherein one of the mechanisms includes a piezoelectric transducer, and another of the mechanisms includes an electromagnetic transducer.

20. The arrangement of claim 19, wherein the electromagnetic transducer includes a soft ferromagnetic material mounted on the scan mirror, and a pair of permanent field magnets for inducing a static magnetic field in the soft ferromagnetic material.