Scanned imaging apparatus with switched feeds

• US 6,515,781 B2
• Filed: 04/20/2001
• Issued: 02/04/2003
• Est. Priority Date: 08/05/1999
• Status: Expired due to Fees

• Current Assignee: Microvision, Inc.
• Original Assignee: Microvision, Inc.
• Inventors: Urey, Hakan, Lewis, John R., Murray, Bernard G.
• Primary Examiner(s): Robinson, Mark A.
• Application Number:
  US09/839,849
• Publication Number:
  US 20020024708A1
• Time in Patent Office: 655 Days
• Field of Search: 359/196, 359/197, 359/204, 359/214, 359/215, 359/220, 359/221, 348/746, 348/747, 348/771, 348/756, 347/234
• US Class Current: 359/199.1
• CPC Class Codes: G02B 26/085 the reflecting means being moved or deformed by electromagnetic means
• CPC Class Codes: G02B 26/101 with both horizontal and vertical deflecting means, e.g. raster or XY scanners colour television using laser beams scanning a display screen H04N9/3129
• CPC Class Codes: G02B 27/017 Head mounted

Abstract

A display apparatus includes a scanning assembly that scans about two or more axes, typically in a raster pattern. A plurality of light sources emit light from spaced apart locations toward the scanning assembly such that the scanning assembly simultaneously scans more than one of the beams. The light sources are positioned such that their beams each illuminate discrete regions of the image field that are substantially non-overlapping with respect to the other discrete regions. The image is thus formed from a set of “tiles”. By activating a first light source during a forward sweep of the mirror and activating a second light source during a reverse sweep of the mirror, two halves a common line can be written during a single sweep of the mirror. Shifting the position of the sources such that the two halves are aligned reduces raster pinch. In alternative embodiments, the same approach is used for imaging. Also, various approaches to controlling the frequency responses of the various scanners are described, including active control of MEMs scanners and passive frequency tuning.

Claims

1. A method of correcting raster pinch in a scanned image capture or display system including a scanning apparatus, comprising the steps of:

activating the scanning apparatus for periodic scanning over a plurality of scanning periods;

during a first portion of each of the scanning periods defining a first scan path between a first optical device and the target area by directing light to or receiving light from the target area with the scanning apparatus;

during a second portion of each of the scanning periods different from the first portion defining a second scan path between a second optical device and the target area by directing light to or receiving light from the target area with the scanning apparatus; and

orienting the first optical device, second optical device and scanning apparatus such that the first and second scan paths define immediately adjacent and substantially nonoverlapping regions in the target area wherein the first and second optical devices are light emitters, further including activating the first optical device only during the first portion of each of the scanning periods and activating the second optical device only during the second portion of each of the scanning periods.

2. A method of correcting raster pinch in a scanned image capture or display system including a scanning apparatus, comprising the steps of:

activating the scanning apparatus for periodic scanning over a plurality of scanning periods;

during a first portion of each of the scanning periods defining a first scan path between a first optical device and the target area by directing light to or receiving light from the target area with the scanning apparatus;

during a second portion of each of the scanning periods different from the first portion defining a second scan path between a second optical device and the target area by directing light to or receiving light from the target area with the scanning apparatus;

orienting the first optical device, second optical device and scanning apparatus such that the first and second scan paths define immediately adjacent and substantially nonoverlapping regions in the target area wherein each of the first and second scan paths are substantially along the common axis; and

translating the first scan path along a second axis different from the common axis during the second portions of the scanning periods.

3. A method of correcting raster pinch in a scanned image capture or display system including a scanning apparatus, comprising the steps of:

activating the scanning apparatus for periodic scanning over a plurality of scanning periods;

during a first portion of each of the scanning periods defining a first scan path between a first optical device and the target area by directing light to or receiving light from the target area with the scanning apparatus;

during a second portion of each of the scanning periods different from the first portion defining a second scan path between a second optical device and the target area by directing light to or receiving light from the target area with the scanning apparatus;

orienting the first optical device, second optical device and scanning apparatus such that the first and second scan paths define immediately adjacent and substantially nonoverlapping regions in the target area wherein each of the first and second scan paths are substantially along the common axis;

translating the first scan path along a second axis different from the common axis during the second portions of the scanning periods; and

translating the second scan path along the second axis during the first portions of the scanning periods.

4. A method of producing an image for viewing, comprising the steps of:

emitting a first light beam from a first location;

resonantly scanning the first light beam about a first axis at a first frequency;

scanning the first light beam about a second axis different from the first axis at a second frequency, while continuing to scan the first light beam about the first axis;

emitting a second light beam from a second location different from the first location;

resonantly scanning the second light beam about the first axis at the first frequency;

scanning the second light beam about the second axis at the second frequency, while continuing to scan the second light beam about the first axis;

modulating the first light beam in a pattern corresponding to a first portion of the image, synchronously with the step of resonantly scanning the first light beam about the second axis; and

modulating the second light beam in a pattern corresponding to a second portion of the image different from the first portion, synchronously with the step of resonantly scanning the second light beam about the second axis; and

wherein the steps of emitting the first light beam and emitting the second light beam are temporally nonoverlapping.

5. The method of claim 4 wherein the steps of resonantly scanning the first and second light beams about the first axis includes:

oscillating a turning mirror at the first frequency; and

redirecting the first and second light beams with the oscillated turning mirror.

6. The method of claim 4 wherein the step of resonantly scanning the first and second light beams about the second axis includes:

pivoting the turning mirror at the second frequency; and

redirecting the first and second light beams with the turning mirror.