OPTICAL SCANNING APPARATUS AND SCANNING IMAGE DISPLAY APPARATUS

Abstract

An optical scanning apparatus in which keystone distortion non-linearity distortion in a projected image can be excellently corrected is provided. An optical scanning apparatus has light source means and deflecting means for deflecting a light beam emitted from the light source means two-dimensionally in a first direction and a second direction, the deflection speed of the deflecting means being higher in the first direction than in the second direction. The deflecting means is driven in such a way that its angular velocity in the second direction is smaller when optically scanning a position on the surface to be scanned at which the angle of incidence of the deflected light beam in the second direction is large than when optically scanning a position on said surface to be scanned at which the angle of incidence of the deflected light beam in said second direction is small.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram schematically showing a scanning image display apparatus according to a first embodiment of the present invention.

FIG. 2 is a diagram schematically showing a horizontal deflector in the first embodiment of the present invention.

FIGS. 3A and 3B are diagrams schematically showing a two dimensional scanning image display apparatus according to a comparative example associated with the first embodiment of the present invention.

FIG. 4 shows a scan image in the comparative example associated with the first embodiment of the present invention.

FIG. 5 is a graph showing angle range in horizontal scanning in relation to vertical position.

FIGS. 6A and 6B are diagrams schematically showing a two dimensional scanning image display apparatus according to the first embodiment of the present invention.

FIG. 7 is a diagram schematically showing a two-dimensional scanning image display apparatus according to a second embodiment of the present invention.

FIGS. 8A and 8B are diagrams schematically showing a two dimensional scanning image display apparatus according to a comparative example associated with the second embodiment of the present invention.

FIG. 9 shows a scan image in the comparative example associated with the second embodiment of the present invention.

FIG. 10 is a graph showing angle range in horizontal scanning in relation to vertical position.

FIGS. 11A and 11B are diagrams schematically showing a two-dimensional scanning image display apparatus according to a third embodiment of the present invention.

FIGS. 12A and 12B are diagrams schematically showing a two dimensional scanning image display apparatus according to a comparative example associated with the second embodiment of the present invention.

Claims

1. An optical scanning apparatus comprising light source means and deflecting means for deflecting a light beam emitted from the light source means two-dimensionally in a first direction and a second direction, deflection speed of the deflecting means being higher in the first direction than in the second direction, and the apparatus scanning a surface to be scanned two-dimensionally with a deflected light beam deflected by the deflecting means in such a way that scanning loci in scanning in the first direction are arranged along the second direction, wherein the deflecting means is driven in such a way that its angular velocity in the second direction is smaller when optically scanning a position on the surface to be scanned at which the angle of incidence of the deflected light beam in the second direction is large than when optically scanning a position on said surface to be scanned at which the angle of incidence of the deflected light beam in said second direction is small.

2. An optical scanning apparatus according to claim 1, wherein said deflecting means is driven in such a way that its angular velocity in said second direction increases or decreased monotonously.

3. An optical scanning apparatus according to claim 1, wherein said deflecting means is driven in such a way that its angular velocity in said second direction is so changed that pitches of scanning loci in said second direction in scanning said surface to be scanned with the deflected light beam become identical.

4. A scanning image display apparatus comprising an optical scanning apparatus according to claim 1 and forming an image on the surface to be scanned.