Non-spherical single lens
AssigneeCanon Kabushiki Kaisha
InventorShigeyuki Suda
Life of this patent
Estimating the term…
Abstract
A non-spherical single lens comprises a first surface which is a non-spherical surface, the first surface being substantially zero in the curvature thereof near the optic axis and being of a non-spherical shape gradually displaced outwardly away from the optic axis, and a second surface which is a convex spherical surface of a radius of curvature r, .vertline.r.vertline. being a value equal or approximate to d which is the thickness of the lens.
Claims6
A non-spherical single lens comprising:
- a first surface which is a non-spherical surface, said first surface being substantially zero in the curvature thereof near the optic axis and being of a non-spherical shape gradually displaced outwardly away from the optic axis;
- and
- a second surface which is a convex spherical surface of a radius of curvature r, .vertline.r.vertline. being a value equal or approximate to d which is the thickness of said lens to such an extent that off-axis aberrations are sufficiently corrected for practical use.
An optical system for converting a parallel light beam into a convergent light beam, comprising:
- a first surface for receiving the parallel light beam;
- a second surface for emitting the convergent light beam;
- and
- a medium contained between said first surface and said second surface for transmitting the light beam from said first surface to said second surface;
- wherein said first surface is composed of a non-spherical surface in which the curvature thereof near the optic axis is substantially zero and which is gradually displaced outwardly away from the optic axis, said first surface is disposed at or in the vicinity of a pupil of said optical system and the center of curvature of said second surface is positioned at or in the vicinity of said first surface.
An optical system for converting a divergent light beam into a parallel light beam, comprising:
- a first surface for receiving the divergent light beam;
- a second surface for emitting the parallel light beam;
- and
- a medium contained between said first surface and said second surface for transmitting the light beam from said first surface to said second surface;
- wherein said first surface is an outwardly convex surface, said second surface is composed of a non-spherical surface in which the curvature thereof near the optic axis is substantially zero and which is gradually displaced outwardly away from the optic axis, said second surface is disposed at or in the vicinity of a pupil of said optical system and the center of curvature of said first surface is positioned at or in the vicinity of said second surface.
Dependencies are inferred from the claim text.