Device for preventing generation of harmful light in objective lens assembly
US5018832A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 31, 1989 |
| Grant date | May 28, 1991 |
| Priority date | — |
| Expiry date | Oct 31, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B7/20
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
In an objective lens assembly for an optical instrument comprising inner and outer tube members with outer and inner engaged helicoidal screws, respectively, the normal trapezoidal-section main ridge of the helicoidal screw of the outer tube member is modified to provide one or more wall surfaces that reflect stray light from the object side of the objective lens assembly to prevent such light from reaching the image side of the assembly. The wall surface or surfaces are provided by one or more sub-ridges or grooves at the top of the trapezoidal-section main ridge. Bottom portions between successive elements of the main ridge may be angulated to prevent stray light reflected therefrom from reaching the image end of the assembly.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.