Method of controlling stray light reflections in an optical system

Abstract

A method of fabricating an optical housing includes forming a pattern comprising a predetermined surface feature on an interior surface of the optical housing. The predetermined surface feature is configured to control reflections of stray light along an optical path between an aperture at a proximal end of the optical housing and a detector at a distal end of the optical housing.

What is claimed is: 
     
         1 . A method of fabricating an optical housing, the method comprising:
 forming a pattern comprising a predetermined surface feature on an interior surface of the optical housing, wherein the predetermined surface feature is configured to control reflections of stray light along an optical path between an aperture at a proximal end of the optical housing and a detector at a distal end of the optical housing.   
     
     
         2 . The method of  claim 1  further comprising mounting one or more input optics to the optical housing. 
     
     
         3 . The method of  claim 1  wherein the optical housing is operable to be mated to an objective lens assembly. 
     
     
         4 . The method of  claim 1  wherein the pattern is formed on an insert that is adapted to be inserted into the optical housing. 
     
     
         5 . The method of  claim 1  wherein the predetermined surface feature comprises a series of geometric structures arranged substantially transverse to an optical axis of the optical housing. 
     
     
         6 . The method of  claim 5  wherein the series of geometric structures are characterized by a symmetric pattern. 
     
     
         7 . The method of  claim 6  wherein the symmetric pattern comprises at least one of a sawtooth pattern, a rounded sawtooth pattern, or a seagull pattern. 
     
     
         8 . The method of  claim 5  wherein the series of geometric structures are characterized by a non-symmetric pattern having an upstream surface facing toward the aperture that is characterized by a curved surface feature and a downstream surface facing toward the detector that is characterized by a substantially planar surface feature. 
     
     
         9 . A method of designing an internal structure of an optical housing, the method comprising:
 providing an optical lens assembly comprising the optical housing and a detector;   receiving a selection of a shape of an internal structure to be disposed on an internal surface of the optical housing;   computing, based on the shape of the internal structure and characteristics of the optical lens assembly, a light intensity at the detector;   determining whether the computed light intensity exceeds a threshold; and   in response to determining that the light intensity does not exceed the threshold, fixing the design of the internal structure.   
     
     
         10 . The method of  claim 9 , further comprising in response to determining that the light intensity exceeds the threshold, modifying the shape of the internal structure so as to reduce the light intensity. 
     
     
         11 . The method of  claim 10 , further comprising repeating the computing, the determining, and the modifying until the light intensity does not exceed the threshold.