Focus Variation Apparatus and Method
AssigneeUniversity of Huddersfield
InventorsHussam Muhamedsalih, Dawei Tang, Aalim Mustafa, Prashant Kumar, Xiang Jiang
Life of this patent
Estimating the term…
Abstract
A focus variation optical apparatus suitable for measuring surface features of materials or substrates and method of use thereof. The apparatus includes at least one light source means and at least one light source means configured to direct a light beam to a mask means. The mask means is configured to project an illumination pattern on the material or substrate and an image sensor is employed to collect images of the surface illuminated by the projected pattern.
Claims22
A focus variation optical apparatus suitable for measuring surface features of materials or substrates, said focus variation optical apparatus comprising:
- a light source means being a tunable laser source or a broadband light source with an acousto-optic tunable filter (AOTF),
- a chromatic objective lens,
- wherein the light source means is configured to direct a light beam to a mask means,
- wherein said mask means is configured to project an illumination pattern on material or substrate surface,
- an image sensor is employed to collect images of a surface illuminated by the projected pattern, and
- wherein the chromatic objective lens scans a focus plane across the optical axis without any mechanical movement.
8-12. (canceled)
(canceled)
A method of measuring surface features using chromatic focus variation, said method including the steps of directing a light beam to a polarised mask to create a pixelated illumination pattern at different intensity levels, projecting the periodic pattern on the measurand surface and recording an image using an image sensor or camera of the tested surface wherein a chromatic lens is used to scan the focus plane across the optical axis, typically without any substantive mechanical movement.
Dependencies are inferred from the claim text.