Scanned imaging apparatus with switched feeds

• US 6,362,912 B1
• Filed: 08/05/1999
• Issued: 03/26/2002
• Est. Priority Date: 08/05/1999
• Status: Expired due to Term

• Current Assignee: Microvision, Inc.
• Original Assignee: Microvision, Inc.
• Inventors: Urey, Hakan, Lewis, John R., Murray, Bernard G.
• Primary Examiner(s): Schuberg, Darren
• Assistant Examiner(s): ASSAF, FAYEZ G
• Application Number:
  US09/370,790
• Time in Patent Office: 964 Days
• Field of Search: 359/204, 359/196, 359/212, 348/746, 348/756, 348/757
• US Class Current: 359/204.1
• CPC Class Codes: G02B 26/085 the reflecting means being moved or deformed by electromagnetic means
• CPC Class Codes: G02B 27/017 Head mounted
• 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 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 device for displaying an image having first and second image portions in response to an image signal, comprising:

an oscillating scanning mirror mounted for periodic motion through a selected scanning pattern having a nonlinear angular velocity;

a driver coupled to the scanning mirror and operative to sweep the scanning mirror through the selected scan pattern;

a first light source responsive to a first input signal to emit a first modulated light beam along a first light path relative to the first light source, the first light source being oriented such that the first light path strikes the scanning mirror at a first angle at which the scanning mirror reflects the first modulated light beam to a first image region in which the first modulated light beam defines the first image portion;

a second light source responsive to a second input signal to emit a second modulated light beam along a second light path relative to the second light source, the second light source being oriented such that the second light path strikes the scanning mirror at a second angle at which the scanning mirror reflects the second modulated light beam toward a second image region in which the second modulated light beam defines the second image portion, and wherein the orientation of the first and second light sources is selected such that the first and second regions are substantially non-overlapping;

electronic control circuitry having an input port for receiving the input signal and first and second outputs coupled to the first and second light sources respectively, the control circuitry being responsive to the image signal to produce the first and second input signals; and

a single light emitter that provides light for both of the first and second light sources wherein the electronic control circuitry includes a clock circuit responsive to the image signal to produce a nonuniform pixel timing clock signal having a nonuniform timing corresponding inversely to the nonlinear angular velocity of the scanning mirror and wherein the pixel timing clock signal defines the timing of the first and second input signals.

2. The device of claim 1 further including

a modulator external to the light emitter.

3. The device of claim 1 wherein the light emitter is directly responsive to the first input light signal to produce the first modulated light beam.

4. The device of claim 1 wherein the scanning mirror is torsionally mounted to a base.

5. The device of claim 1 wherein the light emitter includes an LED.

6. The device of claim 1 wherein the light emitter includes a laser diode.