Optical magnifier suitable for use with a microdisplay device
AssigneeEastman Kodak Company
InventorScott C. Cahall
Life of this patent
Estimating the term…
Abstract
An optical magnifier is provided. One general form of one example embodiment includes two lens elements, at least two aspheric surfaces, and at least one diffractive surface. Another general form of another example embodiment includes three lens elements, and at least three aspheric surfaces. At least two of the aspheric surfaces can be simple conics. The optical magnifier, suitable for use in an electronic display system, has an apparent field of view of at least +/−10 degrees; a magnification of at least 15×; a back focal length of at least 5 mm; and an eye relief greater than the effective focal length of the optical magnifier. The lens elements can be made from plastic.
Claims61
A magnifier lens comprising in order from an eye side:
- a first positive power meniscus lens element having an eye side surface and an object side surface, at least one of the eye side surface and the object side surface being aspheric;
- and
- a second positive power lens element having an aspheric object side surface convex toward the object side and an eye side surface, wherein at least one of the object side surface of the first positive power meniscus element and the eye side surface of the second positive power element is diffractive.
An optical system comprising in order from an eye side:
- a first positive power meniscus lens element having an eye side surface and an object side surface, at least one of the eye side surface and the object side surface being aspheric;
- a second positive power lens element having an aspheric object side surface convex toward the object side and an eye side surface, wherein at least one of the object side surface of the first positive power meniscus element and the eye side surface of the second positive power element is diffractive;
- and
- an object to be viewed.
A magnifier lens comprising in order from an eye side:
- a first positive power lens element having an aspheric eye side surface;
- a second negative power meniscus lens element having an aspheric object side surface;
- and
- a third positive power bi-convex lens element having at least one aspheric surface.
An optical system comprising in order from an eye side:
- a first positive power lens element having an aspheric eye side surface;
- a second negative power meniscus lens element having an aspheric object side surface;
- a third positive power bi-convex lens element having at least one aspheric surface;
- and
- an object to be viewed.
A magnifier lens comprising in order from an eye side:
- a first positive power lens element having an aspheric surface;
- and
- a second positive power lens element having an aspheric surface, the magnifier lens having a back focal length in air, wherein the back focal length of the magnifier lens in air is greater than 5 mm.
Dependencies are inferred from the claim text.