Optical lens
AssigneeRays Optics Inc.
InventorsCHING-LUNG LAI, MENG-WEI LIN
Life of this patent
Estimating the term…
Abstract
An optical lens used for fundus photography includes a first plastic aspheric lens with a positive refractive power, a second plastic aspheric lens, a third plastic aspheric lens, and a fourth plastic aspheric lens with a positive refractive power arranged in order from an object side to an image side. The number of lenses with refractive powers is less than 9, each lens of the optical lens is a singlet lens, a length between respective optical centers of outermost lens surfaces at opposite ends of the optical lens is within a range of 50 mm to 130 mm, and a back focal length is greater than 20 mm.
Claims20
An optical lens used for fundus photography, comprising:
- a first plastic aspheric lens with a positive refractive power, a second plastic aspheric lens with a refractive power, a third plastic aspheric lens with a refractive power, and a fourth plastic aspheric lens with a positive refractive power arranged in order from an object side to an image side, and the first lens and the fourth lens being outermost lenses at opposite ends of the optical lens;
- wherein a number of lenses with refractive powers of the optical lens is less than 9, each lens of the optical lens is a singlet lens, a length between respective optical centers of outermost lens surfaces at opposite ends of the optical lens is within a range of 50 mm to 130 mm, and a back focal length is greater than 20 mm.
An optical lens, comprising:
- a first lens, a second lens, a third lens and a fourth lens arranged in order in a direction, the first lens being an aspheric lens with a positive refractive power, the second lens being an aspheric lens with a refractive power, the third lens being an aspheric lens with a refractive power, and the fourth lens being an aspheric lens with a positive refractive power, a number of lenses with refractive powers of the optical lens being less than 9, a full field of view (FOV) of the optical lens being within a range of 30 degrees to 55 degrees, and the optical lens satisfying the following condition:
- 14<D1/OAL<0.5, where D1 denotes a lens diameter of the first lens, and OAL denotes a length between respective optical centers of outermost lens surfaces at opposite ends of the optical lens.
Dependencies are inferred from the claim text.