US 5,633,754 A · Integrated optical system for endoscopes and the like

Abstract

Optical systems for endoscopes, borescopes, dental scopes, and the like which are characterized by having three groups of lenses of positive optical power and an external entrance pupil. Typically, all three groups of lenses are displaced from the pupil and focal planes. As a consequence, the displaced groups take part in the image transfer as well as in the pupil transfer. The optical power requirements can thus be shifted from one group to another, distributing as well as reducing the overall power requirement. Moreover, the aberration correction can also be shared between these groups. The first group, which conventionally has the highest optical power, and consequently a large amount of aberrations to be corrected, can in this way transfer some of the optical aberration correction to the other groups. The sharing of the optical functions and aberration correction results in a fully integrated optical system. The reduction in the total amount of optical power is so large that a line-of-sight deviating prism can be readily accomodated between the entrance pupil and the first lens group. The resulting simplicity of the optical system makes it suitable as a disposable item.

Claims8

Dependent claims

An endoscopic optical system extending along an optical axis and having an object plane, and having at least a first image plane and a second image plane downstream from the object plane, said system comprising:

at least three spaced-apart groups of optical elements of uniform refractive index disposed serially along the optical axis between the object plane and the second image. plane for transferring an image from the object plane to the second image plane, each of said at least three groups having positive optical power and having at least one element, wherein each element in each of said groups has surfaces and each of said surfaces has a curvature, and the sum of the absolute values of the curvatures of all of said elements in said at least three groups is less than 1.5 when the length of said optical system is standardized to 100 units;
and
means defining a location and a diameter of an entrance pupil at an entrance pupil plane which is positioned between the object plane and the nearest one of said three groups, the entrance pupil plane being spaced apart from said nearest one group by a distance equal to at least the diameter of the entrance pupil.

Dependencies are inferred from the claim text.

Integrated optical system for endoscopes and the like

Life of this patent

Integrated optical system for endoscopes and the like

Life of this patent

Abstract

Claims8