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US 6,980,365 B2Granted
Diffractive lens optical design
Assignee3M Innovative Properties Company
InventorJacob Moskovich
Life of this patent
Estimating the term…
Abstract
An optical system for use in a head-mounted display is provided which includes a microdisplay (4) and a magnifier (10) for producing a magnified image of the microdisplay for viewing by a human eye. The magnifier (10) includes a diffractive surface and has in order: a first element (1) having a first surface (S1) which is convex in the direction of the long conjugate, a block (3) of optical material, and a second element (2) having a second surface (S2) which is convex in the direction of the short conjugate. The first surface (S1) is preferably the diffractive surface. The magnifier provides a long eye relief, a large exit pupil, and a large field of view with a minimum of components.
Claims41
An optical system comprising:
- (A) a microdisplay;
- and
- (B) a magnifier for producing a magnified image of the microdisplay for viewing by a human eye, said magnifier having a focal length fo, a long conjugate side in the direction of the human eye, a short conjugate side in the direction of the microdisplay, and an f-number f# for light passing from the long conjugate to the short conjugate, said magnifier, in order from the long conjugate side to the short conjugate side, comprising:
- (I) a first element having a first surface which is convex in the direction of the long conjugate, said first element having a focal length f1;
- (II) a block of optical material;
- and
- (III) a second element having a second surface which is convex in the direction of the short conjugate, said second element having a focal length f2;
- wherein:
- (a) f1>0;
- (b) f2>0;
- (c) the first surface is a diffractive surface, or the second surface is a diffractive surface, or the magnifier comprises a diffractive surface which is separate from the first and second surfaces;
- (d) axial light passing through the optical system from the long conjugate to the short conjugate and converging at the microdisplay has a beam diameter at the diffractive surface whose maximum value is d;
- and
- (e) the beam diameter value d, the focal length f0, and the f-number satisfy the relationship:
- (f#·d)/f0>0.4.
12 more elements
An optical system comprising:
- (A) a microdisplay;
- and
- (B) a magnifier for producing a magnified image of the microdisplay for viewing by a human eye, said magnifier having a focal length f0, a long conjugate side in the direction of the human eye, and a short conjugate side in the direction of the microdisplay, said magnifier, in order from the long conjugate side to the short conjugate side, comprising:
- (I) a first element having a first surface which is convex in the direction of the long conjugate, said first element having a focal length f1;
- (II) a block of optical material;
- and
- (III) a second element having a second surface which is convex in the direction of the short conjugate, said second element having a focal length f2;
- wherein:
- (a) f1>0;
- (b) f2>0;
- (c) f1/f2>1.0;
- and
- (d) the first surface is a diffractive surface, or the second surface is a diffractive surface, or the magnifier comprises a diffractive surface which is separate from the first and second surfaces.
10 more elements
An optical system comprising:
- (A) a microdisplay;
- and
- (B) a magnifier for producing a magnified image of the microdisplay for viewing by a human eye, said magnifier having a focal length f0, a long conjugate side in the direction of the human eye, and a short conjugate side in the direction of the microdisplay, said magnifier, in order from the long conjugate side to the short conjugate side, comprising:
- (I) a first element having a first surface which is convex in the direction of the long conjugate, said first element having a focal length f1;
- (II) a block of optical material;
- and
- (III) a second element having a second surface which is convex in the direction of the short conjugate, said second element having a focal length f2;
- wherein:
- (a) f1>0;
- (b) f2>0;
- (c) f1/f0>1.3;
- and
- (d) the first surface is a diffractive surface, or the second surface is a diffractive surface, or the magnifier comprises a diffractive surface which is separate from the first and second surfaces.
10 more elements
An optical system comprising:
- (A) a microdisplay;
- and
- (B) a magnifier for producing a magnified image of the microdisplay for viewing by a human eye, said magnifier having a long conjugate side in the direction of the human eye, a short conjugate side in the direction of the microdisplay, and, in order from the long conjugate side to the short conjugate side, comprises:
- (I) a first element having a first surface which is convex in the direction of the long conjugate, said first element having a focal length f1;
- (II) a block of optical material;
- and
- (III) a second element having a second surface which is convex in the direction of the short conjugate, said second element having a focal length f2;
- wherein:
- (a) f1>0;
- (b) f2>0;
- and
- (c) the magnifier comprises a diffractive surface which is closer to the magnifier's long conjugate side than to its short conjugate side.
9 more elements
Dependencies are inferred from the claim text.