Optical measuring system with matched collection lens and detector light guide
OwnerAndrei Brunfeld, Bryan Clark +2inventors
InventorsAndrei Brunfeld, Bryan Clark, Gregory Toker, Morey T. Roscrow
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Abstract
An optical surface inspection system provides dark-field detection avoiding ghost images and without capturing, stray, reflected or re-scattered light. The system includes an illumination system that generates an illumination spot on a surface under inspection collecting lens that collects substantially all light scattered from the surface under inspection from the illumination spot. The system also includes a light guide with a first end having a numerical aperture matched to an exit aperture of the collecting lens and a field of view matched to the illumination spot, and a second end coupled to a detector.
Claims20
An optical inspection system, comprising:
- an illumination subsystem for directing an illumination beam at a surface under inspection to generate an illumination spot at the surface under inspection;
- a collecting lens for collecting light from the surface under inspection, wherein the collecting lens has a large numerical entrance aperture such that substantially all of the light scattered from the surface under inspection from the illumination spot is collected by the collecting lens;
- a light guide having a first end with a numerical aperture matched to an exit numerical aperture of the collecting lens and having a field of view substantially matching the area of the illumination spot;
- and
- a detector coupled to a second end of the light guide for detecting light collected by the collecting lens.
A method of performing an optical inspection, comprising:
- directing an illumination beam at a surface under inspection to generate an illumination spot at the surface under inspection;
- collecting light from the surface under inspection with a collecting lens, wherein the collecting lens has a large numerical entrance aperture such that substantially all of the light scattered from the surface under inspection from the illumination spot is collected by the collecting lens;
- capturing light leaving the collecting lens with a light guide having a first end with a numerical aperture matched to an exit numerical aperture of the collecting lens and having a field of view substantially matching the area of the illumination spot;
- and
- detecting an intensity of the light captured by the capturing with a detector.
An optical inspection system, comprising:
- an illumination subsystem for directing an illumination beam at a surface under inspection to generate an illumination spot at the surface under inspection;
- a collecting lens for collecting light from the surface under inspection, wherein the collecting lens has a large numerical entrance aperture such that substantially all of the light scattered from the surface under inspection from the illumination spot is collected by the collecting lens, and wherein the collection lens defines a void passing through the collection lens and devoid of any lens material and wherein the illumination subsystem directs the illumination beam through the void to generate the illumination spot at the surface under inspection;
- an optical fiber light guide having a first end shaped to provide a numerical aperture matched to an exit numerical aperture of the collecting lens and having a field of view substantially matching the area of the illumination spot;
- and
- a detector coupled to a second end of the light guide for detecting light collected by the collecting lens.
Dependencies are inferred from the claim text.