Compact distorted zoom lens for small angle of view
AssigneeDigitalOptics Corporation Europe Limited
InventorsPavel Reshidko, Gal Shabtay, Ephraim Goldenberg
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Abstract
Providing for optical imaging lenses employing non-linear distortion for image magnification is described herein. By way of example, a five-lens system can perform magnification functions by producing distortion that expands the image in the center of the field of view and compresses the image in the periphery of the field of view. This distortion can be corrected through image processing to yield a rectified image. Further, the five-lens system can be implemented as part of a fixed-focus imaging system, or in conjunction with a variable focus optical magnification imaging system.
Claims44
An optical imaging system for producing a real image of an object and having at least five lens elements arranged along an optical axis, comprising:
- a first lens group having a combined refractive power that is positive, comprising at least:
- a first lens element having positive refractive power and a meniscus shape;
- a second lens element having negative refractive power and a meniscus shape;
- a third lens element having a convex shape on an object side surface at least near the optical axis;
- a rear lens group having a combined refractive power that is negative, comprising one or two of the at least five lens elements;
- wherein:
- the optical imaging system satisfies at least one of the following two conditional expressions:
- ƒ1/ƒ<about 0.876 and ƒ1/ƒG1<about 1.238;
- or
- ƒ1/ƒ<about 1.27 and ƒ1/ƒG1<about 1.12,
- where ƒ1 is a focal length of the first lens element, ƒG1 is a combined focal length of the first lens group, and ƒ is a combined focal length of the optical imaging system.
A method for providing a miniature camera module for a hand-held device, comprising:
- receiving optical information regarding an object by employing at least four lens elements having a common optical axis;
- forming a distorted real image of the object at an imaging surface having a non-constant magnification, wherein a portion of the real image has magnification greater than unity and a second portion of the real image has magnification less than unity;
- and wherein forming the distorted real image of the object further comprises generating an image circle diameter and distorted image circle diameter, wherein:
- a ratio of total track length (TTL) of the camera module to the image circle diameter and a ratio of TTL of the camera module to the distorted image circle diameter are at least one of:
- less than about 1.82 and less than about 1.92, respectively;
- or less than about 1.16 and less than about 1.22, respectively.
Dependencies are inferred from the claim text.