Electronic alignment of primary color pixels in a scanned display

• US 8,223,161 B2
• Filed: 08/22/2007
• Issued: 07/17/2012
• Est. Priority Date: 08/22/2007
• Status: Active Grant

• Current Assignee: Microvision, Inc.
• Original Assignee: Microvision, Inc.
• Inventors: Brown, Margaret K., Freeman, Mark O., Champion, Mark, Swilley, Shawn M., Jakuc, Maciej A.
• Primary Examiner(s): Caschera, Antonio A
• Application Number:
  US11/843,577
• Publication Number:
  US 20090051828A1
• Time in Patent Office: 1,791 Days
• Field of Search: None
• US Class Current: 345/560
• CPC Class Codes: G09G 2320/0242 Compensation of deficiencies in the appearance of colours
• CPC Class Codes: G09G 3/02 by tracing or scanning a light beam on a screen
• CPC Class Codes: H04M 1/0272 for a projector or beamer module assembly constructional features of projectors per se G03B21/00; constructional details of projectors using electronic spatial light modulators per se H04N9/31
• CPC Class Codes: H04N 1/50 Picture reproducers for halftone screening H04N1/52
• 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
• CPC Class Codes: H04N 9/3164 using multiple light sources
• CPC Class Codes: H04N 9/3182 Colour adjustment, e.g. white balance, shading or gamut white balance per se H04N9/73; control of amplitude of colour signals H04N9/68; colour control circuits for displays in general G09G5/02, G09G3/2003, G09G3/3607

Abstract

An image generation apparatus provides correction for color offsets. Color offsets may be caused by misalignments in laser diodes or optics assemblies in a laser projector. The offsets may be measured during or after manufacture of the laser projector. An image buffer is responsive to the offset data to translate each color plane separately. The image buffer may include separately addressable portions for each color. Further, variable delay elements on the output of the image buffer may provide color offset correction. Interpolation provides further offset correction.

Claims

1. An image generation apparatus comprising:

a frame buffer to hold data corresponding to an image made up of display pixels;

a translation component to receive color image data and color offset data, the translation component operable to spatially translate separate color planes within the color image data as specified by the color offset data and to write translated color image data to the frame buffer;

a row buffer coupled to the frame buffer to receive at least one row of pixel data from translated color image data; and

a horizontal scan position determination component to periodically determine a horizontal scan position of a scan trajectory; and

an interpolation component coupled to receive pixel data from the row buffer and operable to interpolate between display pixels on either side of the horizontal scan position in the at least one row.

2. The image generation apparatus of claim 1 further comprising a vertical scan position determination component operable to approximate a vertical scan position of the scan trajectory as a different row for each horizontal sweep of the scan trajectory.

3. The image generation apparatus of claim 1 wherein the horizontal scan position determination component is operable to determine the horizontal scan position as a sine of an increasing angle plus a horizontal offset that is a function of color.

4. The image generation apparatus of claim 1 wherein the horizontal scan position determination component is operable to determine the horizontal scan position as (a sine of an increasing angle) times a multiplier.

5. A mobile device comprising:

a laser projector to project an image, the laser projector including an image generation apparatus having a frame buffer to hold data corresponding to an image made up of display pixels, a translation component to receive the color image data and color offset data, the translation component operable to spatially translate separate color planes within the color image data as specified by the color offset data and to write translated color image data to the frame buffer, a row buffer coupled to the frame buffer to receive at least one row of pixel data from translated color image data, a horizontal scan position determination component to periodically determine a horizontal scan position of a scan trajectory, and an interpolation component coupled to receive pixel data from the row buffer and operable to interpolate between display pixels on either side of the horizontal scan position in the at least one row.

6. The mobile device of claim 5 further comprising a communications receiver.

7. The mobile device of claim 5 further comprising a communications transceiver.

8. The mobile device of claim 7 wherein the communications transceiver is operable to communicate using cellular telephone signals.

9. A method performed by an image generation apparatus comprising:

separately spatially translating each color plane in a color image while writing the color image to a frame buffer within the image generation apparatus;

retrieving at least one row of pixel data from the color image in the frame buffer;

determining a horizontal scan position of a scan trajectory;

horizontally interpolating between pixel data to the left and right of the horizontal scan position to determine a pixel intensity of a new pixel at the horizontal scan position; and

displaying the new pixel at the horizontal scan position.

10. The method of claim 9 further comprising:

determining a vertical scan position of the scan trajectory; and

vertically interpolating between pixel data above and below the vertical scan position; and

combining the horizontal and vertical interpolation to arrive at the pixel intensity of the new pixel at an intersection of the horizontal scan position and the vertical scan position.

11. The method of claim 9 wherein determining a horizontal scan position comprises adding a horizontal offset to a mathematical function of time.