IMAGE PROJECTOR

• US 20080239252A1
• Filed: 03/27/2008
• Published: 10/02/2008
• Est. Priority Date: 03/29/2007
• Status: Active Grant

• Current Assignee: Konica Minolta OPTO Incorporated (Konica Minolta Inc.)
• Original Assignee: Konica Minolta OPTO Incorporated (Konica Minolta Inc.)
• Inventors: Konno, Kenji, Mizumoto, Kenji
• Granted Patent: US 8,218,216 B2
• Time in Patent Office: Days
• US Class Current: 353/98
• CPC Class Codes: F21S 41/675 by moving reflectors
• CPC Class Codes: G02B 17/0621 off-axis or unobscured systems in which not all of the mirrors share a common axis of rotational symmetry, e.g. at least one of the mirrors is warped, tilted or decentered with respect to the other elements
• CPC Class Codes: G02B 26/105 with one or more pivoting mirrors or galvano-mirrors G02B26/101 takes precedence
• CPC Class Codes: G02B 27/0025 for optical correction, e.g. distorsion, aberration
• 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
• CPC Class Codes: H04N 9/3164 using multiple light sources
• CPC Class Codes: H04N 9/3185 Geometric adjustment, e.g. keystone or convergence optical or mechanical adjustment of convergence H04N9/317; using scanning means H04N3/22; optical or mechanical adjustments of projectors not peculiar to the presence of an electronic spatial light modulator G03B21/14
• CPC Class Codes: Y10S 359/904 Micromirror

Abstract

An object of the present invention is to provide an image projector capable of projecting a high-quality image while realizing small size. In the image projector, a light flux is deflected two-dimensionally by turning a reflector for reflecting a light flux emitted from a light source around a second axis almost orthogonal to a first axis as a center by resonant drive while turning the reflector around the first axis as a center by non-resonant drive. Shape of one or more optical surfaces of a projection optical system for projecting an image onto a projection plane by guiding light onto the projection plane includes a shape for performing a correction for maintaining scanning speed of the light flux along one scan direction on the projection plane almost constant and a shape for performing a correction for suppressing a distortion in an image along the other scan direction almost orthogonal to the one scan direction on the projection plane. By controlling turn of the reflector, at least one of a correction for maintaining scanning speed of the light flux along the other scan direction on the projection plane almost constant and a correction for suppressing a distortion in an image along the one scan direction on the projection plane is performed.

Claims

1. An image projector for projecting an image onto a projection plane, comprising:

a light source;

a deflector having a reflector for reflecting a light flux emitted from said light source and two-dimensionally deflecting said light flux by turning said reflector around a first axis as a center and turning said reflector around a second axis as a center, the second axis almost orthogonal to said first axis;

a deflection controller for controlling said reflector so as to be turned around said second axis as a center by resonant drive and so as to be turned around said first axis as a center by non-resonant drive; and

a projection optical system for projecting said image onto said projection plane by guiding the light flux deflected by said deflector onto said projection plane,

wherein shape of one or more optical surfaces of said projection optical system includes a shape for performing a one-scan-direction scan speed correction for maintaining scanning speed of said light flux along one scan direction on said projection plane almost constant and a shape for performing an other-scan-direction distortion correction for suppressing a distortion in an image along the other scan direction almost orthogonal to said one scan direction on said projection plane, and

said deflection controller performs at least one of an other-scan-direction scan speed correction for maintaining scanning speed of said light flux along said other scan direction on said projection plane almost constant by controlling turn of said reflector around said first axis as a center, and a one-scan-direction distortion correction for suppressing a distortion in an image along said one scan direction on said projection plane by controlling turn of said reflector around said second axis as a center.

2. The image projector according to claim 1, wherein said deflection controller performs said other-scan-direction scan speed correction by adjusting a drive signal for turning said reflector around said first axis as a in a display period of an image of each frame.

3. The image projector according to claim 1, wherein said deflection controller performs said other-scan-direction scan speed correction by adjusting a drive signal for turning said reflector around said first axis as a center by a correction signal in a display period of an image of each frame.

4. The image projector according to claim 2, wherein said deflection controller performs said other-scan-direction scan speed correction by adjusting a waveform of a drive signal for turning said reflector around said first axis as a center to a nonlinear shape in a display period of an image of each frame.

5. The image projector according to claim 1, wherein said deflection controller performs said one-scan-direction distortion correction by varying an amplitude of a drive signal for repetitively turning said reflector around said second axis as a center in a display period of an image of each frame.

11. The image projector according to claim 1, wherein said deflection controller controls so as to perform said other-scan-direction scan speed correction.

12. The image projector according to claim 1, wherein said deflection controller controls so as to perform said one-scan-direction distortion correction.

13. The image projector according to claim 1, wherein said deflection controller controls so as to perform both of said other-scan-direction scan speed correction and said one-scan-direction distortion correction.

17. The image projector according to claim 1, wherein said projection optical system includes a first optical plane having a shape for performing said one-scan-direction scan speed correction and a second optical plane having a shape for performing said other-scan-direction distortion correction.

6. An image projector for projecting an image onto a projection plane, comprising:

a light source;

a deflector having first and second reflectors for sequentially reflecting a light flux emitted from said light source, and two-dimensionally deflecting said light flux by turning said first reflector around a first axis as a center and turning said second reflector around a second axis as a center, the second axis apart from said first axis as a reference by a predetermined distance along a predetermined straight line almost orthogonal to said first axis and rotated by almost 90°

around said predetermined straight line as a center;

a deflection controller for controlling said second reflector so as to be turned around said second axis as a center by resonant drive and controlling said first reflector so as to be turned around said first axis as a center by non-resonant drive; and

a projection optical system for projecting said image onto said projection plane by guiding the light flux deflected by said deflector onto said projection plane,

wherein shape of one or more optical surfaces of said projection optical system includes a shape for performing a one-scan-direction scan speed correction for maintaining scanning speed of said light flux along one scan direction on said projection plane almost constant and a shape for performing an other-scan-direction distortion correction for suppressing a distortion in an image along the other scan direction almost orthogonal to said one scan direction on said projection plane, and

said deflection controller performs at least one of an other-scan-direction scan speed correction for maintaining scanning speed of said light flux along said other scan direction on said projection plane almost constant by controlling turn of said first reflector around said first axis as a center, and a one-scan-direction distortion correction for suppressing a distortion in an image along said one scan direction on said projection plane by controlling turn of said second reflector around said second axis as a center.

7. The image projector according to claim 6, wherein said deflection controller performs said other-scan-direction scan speed correction by adjusting a drive signal for turning said first reflector around said first axis as a center in a display period of an image of each frame.

8. The image projector according to claim 6, wherein said deflection controller performs said other-scan-direction scan speed correction by adjusting a drive signal for turning said first reflector around said first axis as a center by a correction signal in a display period of an image of each frame.

9. The image projector according to claim 7, wherein said deflection controller performs said other-scan-direction scan speed correction by adjusting a waveform of a drive signal for turning said first reflector around said first axis as a center to a nonlinear shape in a display period of an image of each frame.

10. The image projector according to claim 6, wherein said deflection controller performs said one-scan-direction distortion correction by varying an amplitude of a drive signal for repetitively turning said second reflector around said second axis as a center in a display period of an image of each frame.

14. The image projector according to claim 6, wherein said deflection controller controls so as to perform said other-scan-direction scan speed correction.

15. The image projector according to claim 6, wherein said deflection controller controls so as to perform said one-scan-direction distortion correction.

16. The image projector according to claim 6, wherein said deflection controller controls so as to perform both of said other-scan-direction scan speed correction and said one-scan-direction distortion correction.

18. The image projector according to claim 6, wherein said projection optical system includes a first optical plane having a shape for performing said one-scan-direction scan speed correction and a second optical plane having a shape for performing said other-scan-direction distortion correction.

19. An image projector for projecting an image onto a projection plane, comprising:

a light source;

a deflector having a reflector for reflecting a light flux emitted from said light source and two-dimensionally deflecting said light flux by turning said reflector around a first axis as a center and turning said reflector around a second axis as a center, the second axis almost orthogonal to said first axis;

a deflection controller for controlling said reflector so as to be turned around said first axis as a center and so as to be turned around said second axis as a center; and

a projection optical system for projecting said image onto said projection plane by guiding the light flux deflected by said deflector onto said projection plane,

wherein one of a one-scan-direction distortion correction for suppressing a distortion in an image along one scan direction on said projection plane and a one-scan-direction scan speed correction for maintaining scanning speed of said light flux along said one scan direction on said projection plane almost constant is performed by using a shape of at least one optical surface in said projection optical system, the other correction is performed by controlling a turn of said reflector by said deflection controller,

one of an other-scan-direction distortion correction for suppressing a distortion in an image along the other scan direction almost orthogonal to said one scan direction on said projection plane and an other-scan-direction scan speed correction for maintaining scanning speed of said light flux along said other scan direction on said projection plane almost constant is performed by using a shape of at least one optical surface in said projection optical system, and the other correction is performed by controlling a turn of said reflector by said deflection controller.

20. An image projector for projecting an image onto a projection plane, comprising:

a light source;

a deflector having first and second reflectors for sequentially reflecting a light flux emitted from said light source, and two-dimensionally deflecting said light flux by turning said first reflector around a first axis as a center and turning said second reflector around a second axis as a center, the second axis apart from said first axis as a reference by a predetermined distance along a predetermined straight line almost orthogonal to said first axis and turned by almost 90°

around said predetermined straight line as a center;

a deflection controller for controlling said first reflector so as to be turned around said first axis as a center and controlling said second reflector so as to be turned around said second axis as a center; and

a projection optical system for projecting said image onto said projection plane by guiding the light flux deflected by said deflector onto said projection plane,

wherein one of a one-scan-direction distortion correction for suppressing a distortion in an image along one scan direction on said projection plane and a one-scan-direction scan speed correction for maintaining scanning speed of said light flux along said one scan direction on said projection plane almost constant is performed by using a shape of at least one optical surface in said projection optical system, the other correction is performed by controlling a turn of said first or second reflector by said deflection controller,

one of an other-scan-direction distortion correction for suppressing a distortion in an image along the other scan direction almost orthogonal to said one scan direction on said projection plane and an other-scan-direction scan speed correction for maintaining scanning speed of said light flux along said other scan direction on said projection plane almost constant is performed by using a shape of at least one optical surface in said projection optical system, and the other correction is performed by controlling a turn of said first or second reflector by said deflection controller.