Shadow moire surface measurement using Talbot effect
Patent 6731391 Issued on May 4, 2004. Estimated Expiration Date: 
January 29, 2021. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
January 29, 2021. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent References 3858981 Automatic focusing system with dual diffraction gratings and converging means Optical linear encoder Optical head for optical disk system Apparatus and method for optically measuring a surface Patent #: 5311286 InventorsApplicationNo. 09674822 filed on 01/29/2001US Classes:356/605, Moire250/237GGratings (moire fringes)ExaminersPrimary: Rosenberger, Richard A.Attorney, Agent or FirmInternational ClassG01B 1124AbstractA method and apparatus for surface measurement using the shadow moire effect with the Talbot effect. The apparatus includes a specimen mount to receive a specimen having a surface to be measured, and a reference grating mounted adjacent to the specimen mount so as to be substantially parallel to a mean surface plane of the specimen. The reference grating is mounted in such a manner that the distance between the reference grating and the mean surface plane of the specimen can be adjusted to a Talbot distance δT. The apparatus also includes a light source to illuminate the specimen through the grating and a detector positioned to detect the moire fringes produced by the grating due to variation of the surface of the specimen. | |
