Projecting optical unit and projecting type image display apparatus therewith
View Patent ↗A projection image display device is disclosed in which a trapezoidal distortion and/or aberration are restrained when an image is enlarged and projected obliquely onto a screen. An image generator is connected to an optical system base in such a manner that at least an inclination thereof (on an axis parallel to X axis) with respect to a vertical line and a distance thereof in forward and backward direction (Z axis direction) can be adjusted by an adjusting mechanism. Further, a projecting lens 2 as a first optical system and a free-form curved surface mirror as a second optical system are fixed to the optical system base. The free-form curved surface mirror is rotatable (on an rotary axis parallel to X axis) with respect to the vertical line at a substantial center of the free-form curved surface mirror.
1. A projection optical unit for projecting an image on a screen, the projection optical unit comprising:
an image display element including a display surface for forming thereon the image;
a first optical system including at least one rotationally asymmetrical lens having a concave surface from which a light is emitted, the asymmetrical lens having a shape rotationally asymmetrical with respect to an optical axis of the first optical system;
a second optical system having at least one convex mirror including a convex reflection surface for receiving and reflecting the light emitted from the first optical system in such a manner that the light reaches the screen with a predetermined angle relative to a normal line with respect to the screen; and
an optical system support unit for supporting the first and second optical systems, wherein:
the convex mirror is supported by the optical system support unit to be rotatable on an axis passing a substantial center of the convex reflection surface, and
the image display element is movable to adjust an angle of an imaginary straight line extending perpendicularly to the display surface and passing a center of the display surface, with respect to the optical axis of the first optical system.
2. The projection optical unit according to claim 1 , wherein:
the convex mirror is movable to adjust an angle of the light received by the convex reflection surface, with respect to the convex reflection surface, and
the image display element is movable to direct the imaginary straight line toward the screen.
3. The projection optical unit according to claim 2 , wherein:
the first and second optical systems are fixed to the optical system support unit in their respective directions of optical axes, and
the image display element is mounted on the optical system support unit in a movable manner in a direction of its optical axis.
4. The projection optical unit according to claim 1 , wherein:
the first optical system includes a second lens,
the rotationally asymmetrical lens is arranged between the second lens and the screen, and
a curvature of a part of the rotationally asymmetrical lens through which a portion of the light proceeding toward a lower end of the screen passes is greater than a curvature of another part of the rotationally asymmetrical lens through which another portion of the light proceeding toward an upper end of the screen passes.
5. The projection optical unit according to claim 4 , wherein a curvature of a part of the convex mirror through which a portion of the light proceeding toward a lower area of the screen reflects is greater than a curvature of another part of the convex minor through which another portion of the light proceeding toward an upper area of the screen reflects.
6. A projection type image display apparatus comprising:
a screen;
an image display element including a display surface for forming thereon the image;
a first optical system including at least one rotationally asymmetrical lens having a concave surface from which a light is emitted, the rotationally asymmetrical lens having a shape rotationally asymmetrical with respect to an optical axis of the first optical system;
a second optical system having at least one convex mirror including a convex reflection surface for receiving and reflecting the light emitted from the first optical system in such a manner that the light reaches the screen with a predetermined angle relative to a normal line with respect to the screen; and
an optical system support unit for supporting the first and second optical systems, wherein:
the convex mirror is supported by the optical system support unit to be rotatable on an axis passing a substantial center of the convex reflection surface, and
the image display element is movable to adjust an angle of an imaginary straight line extending perpendicularly to the display surface and passing a center of the display surface, with respect to the optical axis of the first optical system.
7. The projection type image display apparatus according to claim 6 , further comprising:
a planar minor for reflecting the light emitted from the second optical system so that the light is projected therefrom onto the screen.