Illumination light source and two-dimensional image display using same

• US 20060285078A1
• Filed: 02/24/2005
• Published: 12/21/2006
• Est. Priority Date: 02/27/2004
• Status: Active Grant

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Mizuuchi, Kiminori, Kasazumi, Ken'ichi, Yamamoto, Kazuhisa
• Granted Patent: US 7,677,736 B2
• Time in Patent Office: Days
• US Class Current: 353/37
• 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: G03B 21/28 Reflectors in projection beam in illumination beam G03B21/2066
• 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 2-D beam scan method using a galvanometer mirror and a polygon scanner has a problem that the polygon scanner is large and noises are increased. Also, a method of oscillating a compact mirror has a problem that a brightness distribution is produced depending on a scan angle. Hence, a beam is scanned while a relatively small mirror, such as an MEMS mirror, is oscillated at or in the vicinity of the resonance frequency. In this instance, the scan angle is corrected with the use of a correction optical system for uniform illumination to be achieved.

Claims

1-10. -10. (canceled)

11. An illumination light source comprising:

a coherent light source;

beam scan means for scanning light from the coherent light source; and

a correction optical system that corrects a scan angle of a beam scanned by the beam scan means, wherein;

the beam scan means is formed of a mirror portion and mirror portion oscillation means; and

the mirror portion is driven by the mirror portion oscillation means at or in a vicinity of a primary resonance frequency of the mirror portion.

12. The illumination light source according to claim 11, wherein:

the correction optical system is formed of a light collection optical system having third-order spherical aberration.

13. The illumination light source according to claim 11, further comprising:

light shield means for shielding, of the light from the coherent light source, light whose scan angle by the beam scan means is at a ratio equal to or larger than a specific ratio with respect to a maximum scan angle.

14. The illumination light source according to claim 11, wherein:

a scan rate of light having passed through the correction optical system takes a minimal value at a point at which the scan angle is 0.

15. The illumination light source according to claim 11, wherein

a scan rate of light having passed through the correction optical system is 90% or less of a maximum value of the scan rate at a point at which the scan angle is 0.

16. The illumination light source according to claim 13, wherein:

the light shield means shields the light from the coherent light source for a time that accounts for 30% or less of a scan time.

17. The illumination light source according to claim 11, wherein:

the correction optical system is formed of a free-form mirror.

18. The illumination light source according to claim 11, wherein:

the coherent light source is formed of a red coherent light source, a green coherent light source, and a blue coherent light source.

19. The illumination light source according to claim 11, wherein:

at least the green coherent light source is formed of a second harmonic generator device that generates green light through wavelength conversion of light from a coherent light source having an infrared wavelength.

20. A 2-D image display device comprising:

the illumination light source according to claim 11;

and

a projection optical system that projects light from the illumination light source onto a screen.