Scanned beam display

• US 20020024495A1
• Filed: 07/02/2001
• Published: 02/28/2002
• Est. Priority Date: 08/05/1998
• Status: Active Grant

• Current Assignee: Microvision, Inc.
• Original Assignee: Microvision, Inc.
• Inventors: Tegreene, Clarence T., Lippert, Thomas M.
• Granted Patent: US 6,937,221 B2
• Time in Patent Office: Days
• US Class Current: 345/98
• CPC Class Codes: G02B 23/12 with means for image conversion or intensification

Abstract

A display apparatus includes first and second IR or other light sources that produce light at respective first and second non-visible wavelengths. The light is modulated according to a desired image. The modulated light is then applied to a wavelength selective phosphor that converts each component of the light to a respective visible wavelength. In one embodiment, the image source is a scanned light beam display that scans an IR light beam onto a screen that carries the phosphor.

Claims

1. A display device that produces a visible image in response to an input image signal having a plurality of components, comprising:

a screen, including a base plate and a wavelength converting coating responsive to output light of a first visible wavelength range in response to light of a first input wavelength, and responsive to output light of a second visible wavelength range in response to light of a second input wavelength;

a first light emitter operative to emit modulated light of the first input wavelength in response to a first component of the image signal;

a second light emitter operative to emit modulated light of the second input wavelength in response to a first component of the image signal; and

a scanner assembly having an input aligned optically to receive light from the first and second light sources and an output aligned optically to direct the light received at the input to the screen, the scanner assembly being responsive to a driving signal to scan the received light onto the wavelength converting coating in a periodic pattern.

2. The display of claim 1 wherein the first input wavelength is a non-visible wavelength.

3. The display of claim 2 wherein the first input wavelength is a non-visible wavelength.

4. The display of claim 1 wherein the scanner assembly includes a mirror mounted for pivotal movement about an axis of rotation.

5. The display of claim 1 wherein the scanner assembly includes a microelectromechanical scanner having a mirror positioned to deflect the light received at the input.

6. The display of claim 1 wherein the wavelength converting coating includes a first infrared sensitive phosphor compound and the first input wavelength is an infrared wavelength.

7. The display of claim 1 wherein the wavelength converting coating includes a second infrared sensitive phosphor compound responsive to the second input wavelength.

8. The display of claim 1 wherein first light source includes a first laser diode.

9. The display of claim 8 wherein first light source includes an external modulator.

10. The display of claim 8 wherein second light source includes a second laser diode.

11. The display of claim I further including a beam combiner interposed between the scanner assembly and the first and second light sources, the beam combiner having a first input aligned to the first light source, a second input aligned to the second light source, and a combiner output aligned to the scanner assembly, the combiner being responsive to produce a single combined beam from the modulated light at the first wavelength and the modulated light at the second wavelength.

13. The display of claim 12 wherein the light source includes a first infrared laser operative to emit light in a first range of wavelengths.

14. The display of claim 13 wherein the light source includes a second infrared laser operative to emit light in a second range of wavelengths different from the first range.

15. The display of claim 14 wherein the wavelength converting coating, the coating is responsive to light in the first wavelength range to emit visible light of a first color and responsive to light in the second wavelength range to emit visible light of a second color different from the first color.

16. The display of claim 12 wherein the wavelength converting coating, includes a plurality of phosphor combinations, each of the phosphor combinations being responsive to non-visible light of a respective wavelength to emit light of a respective visible wavelength.

17. The display of claim 12 wherein the scanner is a MEMs scanner.

18. The display of claim 12 wherein the scanner includes a resonant scanning portion.

19. The display of claim 12 wherein the periodic pattern is a substantially raster pattern.

12. A head mounted display, comprising:

an image signal source that produces an image signal corresponding to a desired image;

a screen having a wavelength converting coating, the coating being responsive to non-visible radiation to emit visible light;

a light source responsive to the image signal to emit non-visible radiation modulated according to the image signal; and

a scanner positioned to receive the modulated light and operative to scan the received light onto the screen in a periodic pattern.

20. A method of providing a visible image to a user, comprising the steps of:

producing light of a first non-visible wavelength;

producing light of a second non-visible wavelength;

modulating the light of the first non-visible wavelength with a first portion of image information;

modulating the light of the second non-visible wavelength with a second portion of image information;

scanning the light of the first non-visible wavelength in a periodic pattern;

scanning the light of the second non-visible wavelength in a periodic pattern;

converting the scanned light of the first non-visible wavelength into light of a first visible wavelength;

converting the scanned light of the second non-visible wavelength into light of a second visible wavelength; and

directing the converted light of the first and second visible wavelengths to the user.

21. The method of claim 20 wherein the step of modulating light with image information includes the steps of:

emitting continuous wave light of the first non-visible wavelength with a light source; and

modulating the continuous wave light with an external amplitude modulator separate from the light source.

22. The method of claim 20 wherein the step of scanning the light of the first non-visible wavelength in a periodic pattern includes directing the light of the first non-visible wavelength through a substantially raster pattern.

23. The method of claim 22 wherein the step of directing the light of the first non-visible wavelength in through a substantially raster pattern includes redirecting the light of the first non-visible wavelength with a scanning mirror.

24. The method of claim 20 wherein the step of converting the scanned light of the first non-visible wavelength into light of a first visible wavelength includes applying the scanned light to a phosphor combination.

25. The method of claim 20 further including the step of combining the light of the first and second non-visible wavelengths before the steps of scanning the light of the first and second non-visible wavelengths.

26. The method of claim 20 wherein the step of producing light of the first non-visible wavelength includes activating a laser diode.

27. The method of claim 26 wherein the step of modulating the light of the first non-visible wavelength with a first portion of image information includes modulating a drive current to the laser diode.

29. The method of claim 28 wherein the step of directing the emitted infrared light of the first wavelength to wavelength converting material includes scanning the infrared light of the first wavelength through a substantially raster pattern.

30. The method of claim 29 wherein the step of directing the emitted infrared light of the second wavelength to wavelength converting material includes scanning the infrared light of the second wavelength through a substantially raster pattern.

31. The method of claim 30 wherein scanning the infrared light of the first wavelength through a substantially raster pattern includes:

directing the infrared light of the first wavelength onto a scanning mirror; and

pivoting the scanning mirror through a periodic scanning pattern.

28. A method of producing an image for viewing by a user, comprising the steps of:

producing a first electrical image signal corresponding to a first portion of the image to be viewed;

producing a second electrical image signal corresponding to a first portion of the image to be viewed;

applying the first image signal to a first image source;

applying the second image signal to a second image source;

emitting infrared light of a first wavelength range in response to the applied first image signal;

emitting infrared light of a second wavelength range different from the first wavelength range in response to the applied second image signal;

directing the emitted infrared light of the first wavelength to wavelength converting material;

directing the emitted infrared light of the second wavelength to wavelength converting material;

emitting visible light of a first visible wavelength with the wavelength converting material in response to the directed emitted light of the first wavelength; and

emitting visible light of a second visible wavelength with the wavelength converting material in response to the directed emitted light of the second wavelength.