Non-sampled auto-format conversion method

• US 6,751,001 B1
• Filed: 01/24/2003
• Issued: 06/15/2004
• Est. Priority Date: 01/24/2003
• Status: Expired due to Fees

• Current Assignee: Evans & Sutherland Computer Corp. (Elevate Entertainment, Inc.)
• Original Assignee: Evans & Sutherland Computer Corp. (Elevate Entertainment, Inc.)
• Inventors: McAllister, Aaron S., Tanner, Allen H.
• Primary Examiner(s): Schwartz, Jordan M.
• Assistant Examiner(s): STULTZ, JESSICA T
• Application Number:
  US10/350,917
• Time in Patent Office: 508 Days
• Field of Search: 359/290, 359/291, 359/298, 359/558, 359/276, 359/277, 359/566, 359/278, 359/238, 250/208.1, 250/216
• US Class Current: 359/238
• CPC Class Codes: G02B 27/09 Beam shaping, e.g. changing the cross-sectional area, not otherwise provided for adapting the beam shape of a laser diode G02B19/0052; adapting the beam shape of an LED G02B19/0061; coupling into light guides using intermediate optical elements G02B6/4204; beam shaping specially adapted for lasers H01S3/005
• CPC Class Codes: H04N 5/7416 involving the use of a spatial light modulator, e.g. a light valve, controlled by a video signal
• 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 device for the passive conversion of one format to another includes: a laser light source at a predetermined frequency, a line converter configured to produce a fan of light, a movable lens configured to collimate the fan of light, and an array of light modulators placed such that the collimated light is incident on a portion of the light modulators. Vertical pixels of an input image are reproduced on either 1, 2, 3, etc, adjacent light modulators depending on the target image size to produce a modulated light column. Any discrepancy between the modulated light column height and the target image height is compensated for using a zoom lens. The modulated light column is then reflected to a display surface. An entire image is produced by changing the state of the array of light modulators to correspond with each of the vertical columns of the image and sweeping the vertical columns across the display surface. The method accomplishes the format conversion passively, in that, simple calculations are performed only once for each input image size. Further, the image produced has no discontinuities or artifacts and results in a dramatically improved picture quality.

Claims

1. A passive image format conversion device, comprising:

a) a laser light source configured to produce an energy beam at a predetermined frequency along a given optical path;

b) a line converter placed in the optical path for converting the energy beam to a fan of light;

c) a lens moveable with respect to the light source and placed along the optical path within the fan of light subsequent to the line converter and configured to collimate the fan of light to produce a collimated light column; and

d) an array of N light modulators placed in the path of the collimated light column, wherein the moveable lens may be displaced along the optical path to produce a collimated light column of variable image sizes incident on a predetermined portion of the light modulators.

2. A device in accordance with claim 1, further comprising an input image signal operatively connected to the array wherein the input image signal has n vertical pixel data over h columns, wherein within each column the n pixel data are modulated on kn light modulators, where n, h and k are positive non-zero integers and kn/N defines the predetermined portion of light modulators and the corresponding variable image size, to produce a modulated light column which is directed toward a projection surface.

3. A device in accordance with claim 2, further comprising a movable mirror oriented to reflect the modulated light column toward the projection surface and wherein each of the h columns of data are modulated consecutively over a given time.

4. A device in accordance with claim 2 or 3, further comprising a zoom lens placed along the optical path of the modulated light column after the array and before the projection surface.

5. A device in accordance with claim 4, further comprising a Schlieren stop placed in the optical path of the modulated light column before the zoom lens.

6. A device in accordance with claim 1, wherein the line converter is a Powell lens.

7. A device in accordance with claim 1, wherein the laser light source produces a light having a frequency within a range selected from the group consisting of blue, red and green.

8. A device in accordance with claim 1, wherein the laser light source produces a light having a frequency within the infrared range.

9. A device in accordance with claim 1, wherein each of the N light modulators is a grating light valve device having a primary ribbon and a reference ribbon.

10. A device in accordance with claim 9, wherein N is greater than 480.

11. A method for passive up-conversion of an image, comprising the steps of:

a) providing laser light source configured to produce laser light having a predetermined frequency;

b) producing a fan of light from the laser light;

c) providing a lens at variable distances from the laser light source, wherein the variable distance is chosen to select a variable image size to produce a collimated light column of a predetermined size;

d) providing a first digital image wherein each vertical pixel is modulated on an integral number of adjacent light modulators placed in a linear array;

e) directing the column of light onto the array of light modulators, wherein the column size is incident on an integer multiple number of the light modulators to produce a modulated column of light;

f) using a zoom lens to adjust the column height of the modulated light column to correspond to a second digital image vertical height; and

g) directing the modulated light column onto a display surface.

12. A method in accordance with claim 11, wherein the step of directing further comprises using a movable mirror to direct the modulated light column and moving the mirror at a rate configured to sweep across a second digital image width of columns to produce a two dimensional image.

13. A method in accordance with claim 12, wherein the step of providing a laser light source further comprises:

a) providing red, blue and green pulsed laser light sources wherein each laser light source is pulsed at a predetermined frequency; and

b) combining the red, blue and green pulsed laser light sources such that the resulting laser light has consecutive intervals of each color.