Test head for optically inspecting workpieces comprising a lens for elongating a laser spot on the workpieces
US7292329B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 23, 2005 |
| Grant date | Nov 6, 2007 |
| Priority date | — |
| Expiry date | May 24, 2025 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N21/8806
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An optical test head comprises a laser source for providing a laser beam. The laser beam passes through a cylindrical lens for modifying the shape of the beam and a spherical lens for concentrating the beam onto a workpiece (typically a magnetic disk platter). The cylindrical lens both a) elongates the laser beam along the radial direction of the platter (by reducing the effective numerical aperture in the radial direction); and b) causes the beam to be out of focus in the radial direction (although the beam is typically in focus in the circumferential direction). The size of the beam in the radial direction is substantially insensitive to the position of the cylindrical lens.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.