Projection display device

• US 6,945,652 B2
• Filed: 06/27/2002
• Issued: 09/20/2005
• Est. Priority Date: 07/10/2001
• Status: Expired due to Fees

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Furukawa, Yukio, Sakata, Hajime
• Primary Examiner(s): Gray, David
• Assistant Examiner(s): Cruz, Magda
• Application Number:
  US10/180,114
• Publication Number:
  US 20030011751A1
• Time in Patent Office: 1,181 Days
• Field of Search: 353 30- 31, 353 33- 34, 353/37, 353 98- 99, 353/122, 348195-205, 359/201
• US Class Current: 353/30
• CPC Class Codes: G03B 21/2033 LED or laser light sources
• 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

Light beams having different wavelengths emitted from red and blue semiconductor lasers and a laser diode pumped green solid-state laser are incident on respectively different surfaces of a color combining element and are overlaid on a single light path. Multiple beam interference films of the color combining element allow only the light beams having the oscillating wavelengths corresponding to the respective light sources to pass therethrough or reflect thereon so as to combine the light beams. A collimator collimates the light beams so that the beam waist of the light beams lies around a projection plane. When two-dimensional scanning is performed by radiating the light beams onto a micromechanical mirror and then onto a galvanometer mirror for scanning light in the horizontal and vertical directions, respectively, a color image is displayed on the projection plane by arranging pixels in array, each pixel consisting of overlapping pulses of light of three colors.

Claims

1. A projection display device for displaying an image by projecting light beams onto a projection plane, comprising:

light sources for emitting the light beams; and

light scanning elements for scanning the emitted light beams toward the projection plane,

wherein the light beams are radiated as pulses of light corresponding to respective pixels by splitting the light beams between adjacent pixels when the light beams are being scanned.

2. The projection display device according to claim 1, wherein the light beams are plural light beams having central wavelengths of red, green, and blue colors.

3. The projection display device according to claim 2, wherein the plural light beams are combined on a single light path by a color combining element.

4. The projection display device according to claim 3, wherein the plural light beams comprise pulses of red, green, and blue light which are emitted synchronously.

5. The projection display device according to claim 2, wherein the plural light beams are incident on at least one of said light scanning elements at different angles and then are scanned.

6. The projection display device according to claim 2, wherein the plural light beams are incident at different points on at least one of said light scanning elements and are scanned.

7. The projection display device according to claim 1, wherein the pulses of light achieve tone and hue of the display image by performing pulse width modulation in a pixel clock width.

8. The projection display device according to claim 1, wherein the pulses of light achieve tone and hue of the display image by performing a pulse number modulation in a pixel clock width.

9. The projection display device according to claim 1, wherein the pulses of light achieve tone and hue of the display image by performing light intensity modulation.

10. The projection display device according to claim 1, wherein the pulses of light achieve tone and hue of the display image by being controlled independtly of each other with respect to the plurality of light beams.

11. The projection display device according to claim 1, wherein said light scanning elements scan the light beams in a horizontal scanning direction and a vertical scanning direction and display an image on the projection plane.

12. The projection display device according to claim 11, wherein at least one of said light scanning elements is a galvanometer mirror fabricated by a semiconductor process.

13. The projection display device according to claim 11, wherein at least one of said light scanning elements is a mechanically fabricated galvanometer mirror.

14. The projection display device according to claim 11, wherein at least one of said light scanning elements is a rotating polygonal mirror.

15. The projection display device according to claim 11, wherein at least one of said light scanning elements is a silicon micromechanical mirror.

16. The projection display device according to claim 11, wherein at least one of said light scanning elements is a scanning element with a gimbal structure.

17. The projection display device according to claim 1, wherein at least one of said light sources for emitting the light beams is an edge emitting laser.

18. The projection display device according to claim 1, wherein at least one of said light sources for emitting the light beams is a super-luminescent diode.

19. The projection display device according to claim 1, wherein at least one of said light sources for emitting the light beams is a surface emitting laser.

20. The projection display device according to claim 1, wherein at least one of said light sources for emitting the light beams is a light emitting diode.

21. The projection display device according to claim 1, wherein at least one of said light sources for emitting the light beams is a resonant-type light emitting diode.

22. The projection display device according to claim 1, wherein at least one of said light sources for emitting the light beams is a laser diode pumped solid-state laser.

23. The projection display device according to claim 22, wherein said laser diode pumped solid-state laser emits wavelength converted light from one of an optical crystal, a piece of glass doped with a rare earth element or pigment, and a fiber doped with a rare earth element or pigment, the wavelength converted light being induced by semiconductor laser light.

24. The projection display device according to claim 1, wherein at least one of said light sources for emitting the light beams emits the second harmonic of laser light as a light beam.

25. The projection display device according to claim 24, wherein said light source for exciting the second harmonic of the laser light is a semiconductor laser or an LD pumped solid-state laser.

26. A projection display device for displaying an image by projecting light beams onto a projection plane, comprising:

light source means for emitting light beams; and

light scanning means for scanning the emitted light beams toward the projection plane, wherein

the light beams from said light source means are radiated as pulses of light corresponding to respective pixels by splitting the light beams between adjacent pixels,when the light beams are being scanned.

27. The projection display device according to claim 26, wherein said scanning means includes first scanning means for scanning light beams in a horizontal direction, and second scanning means for scanning light beams in a vertical direction.

28. The projection display device according to claim 27, wherein at least one of said first and second scanning means is a galvanometer mirror fabricated by a semiconductor process.

29. The scanning means according to claim 27, wherein at least one of said first and second scanning means is a mechanically fabricated galvanometer mirror.

30. The scanning means according to claim 27, wherein at least one of said first and second scanning means is a rotating polygonal mirror.

31. The scanning means according to claim 27, wherein at least one of said first and second scanning means is a silicon micromechanical mirror.

32. The scanning means according to claim 27, wherein said first and second scanning means are arranged in a gimbal structure.