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US 11,635,591 B2Granted
Lens attachment of reduced focus and increased light admittance
OwnerMuji Huanginventor
Life of this patent
Estimating the term…
Abstract
A lens attachment, used with an objective lens, including from object side to image side, a first lens element with positive power, a second lens element with negative power, a third lens element with positive power, a fourth lens element with negative power, and a fifth lens element with positive power; the second and third lens elements form a doublet by adhesive; at least two of the third, fourth and fifth lens elements are anomalous dispersion lenses.
Claims10
A lens attachment, adapted to be used with an objective lens;
- the lens attachment comprises, in a sequential order from an object side to an image side:
- a first lens assembly, comprising a first lens element which is a crescent-shape spherical lens having a positive power wherein a front surface of the first lens element is convex towards the object side and a rear surface of the first lens element is concave towards the object side;
- a second lens assembly, comprising a second lens element and a third lens element;
- the second lens element is a biconcave spherical lens having a negative power wherein a front surface of the second lens element is concave towards the image side and a rear surface of the second lens element is concave towards the object side, the third lens element is a biconvex spherical lens having a positive power wherein a front surface of the third lens element is convex towards the object side and a rear surface of the third lens element is convex towards the image side;
- the second lens element and the third lens element form a doublet by pairing with each other via adhesive;
- a third lens assembly, comprising a fourth lens element which is a biconcave spherical lens having a negative power wherein a front surface of the fourth lens element is concave towards the image side and a rear surface of the fourth lens element is concave towards the object side;
- and
- a fourth lens assembly, comprising a fifth lens element which is a biconvex lens having a positive power wherein a front surface of the fifth lens element is convex towards the object side and a rear surface of the fifth lens element is convex towards the image side;
- the lens attachment fulfills the following requirement:
- 1<(CvObj2+CvIma4)/φ<3;
- and 0.5<M<1;
- wherein φ is a power of the lens attachment, M is an overall magnification of the lens attachment, CvObj2 is a curvature of an object-side surface of the second lens element, CvIma4 is a curvature of an image-side surface of the fourth lens element;
- at least two of the third lens element, the fourth lens element and the fifth lens element are anomalous dispersion lenses.
10 more elements
A lens attachment, adapted to be used with an objective lens and an imaging unit;
- the lens attachment comprises, in a sequential order from an object side to an image side:
- a first lens assembly, comprising a first lens element which is a crescent-shape spherical lens having a positive power wherein a front surface of the first lens element is convex towards the object side and a rear surface of the first lens element is concave towards the object side;
- a second lens assembly, comprising a second lens element and a third lens element;
- the second lens element is a biconcave spherical lens having a negative power wherein a front surface of the second lens element is concave towards the image side and a rear surface of the second lens element is concave towards the object side, the third lens element is a biconvex spherical lens having a positive power wherein a front surface of the third lens element is convex towards the object side and a rear surface of the third lens element is convex towards the image side;
- the second lens element and the third lens element form a doublet by pairing with each other via adhesive;
- a third lens assembly, comprising a fourth lens element which is a biconcave spherical lens having a negative power wherein a front surface of the fourth lens element is concave towards the image side and a rear surface of the fourth lens element is concave towards the object side;
- and
- a fourth lens assembly, comprising a fifth lens element which is a biconvex lens having a positive power wherein a front surface of the fifth lens element is convex towards the object side and a rear surface of the fifth lens element is convex towards the image side;
- the lens attachment fulfills the following requirement:
- 1<(CvObj2+CvIma4)/φ<3;
- and 0.5<M<1;
- wherein φ is a power of the lens attachment, M is an overall magnification of the lens attachment, CvObj2 is a curvature of an object-side surface of the second lens element, CvIma4 is a curvature of an image-side surface of the fourth lens element;
- at least two of the third lens element, the fourth lens element and the fifth lens element are anomalous dispersion lenses.
10 more elements
Dependencies are inferred from the claim text.