study on scanning methods using diffractive grating dots

• Main Authors: Ching Chung Wang, 王敬中
• Other Authors: Sheng Lih Yeh
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/28522953113851865200

碩士 === 龍華科技大學 === 機械系碩士班 === 94 === The techniques to measure surface features can be divided into measuring two-dimensional (2-D) outlines and measuring three-dimensional (3-D) profiles. The techniques to measure 3-D profiles are more complex than those to measure 2-D outlines, and the former include laser scanners, scanning probes, and microscopic profilemeters. But some of the above-mentioned techniques are not very precise, some of them are slow and some of them are performed for small scanning sizes only. This study will focus on the techniques to simultaneously create multiple scanning lines by using digital gratings. These techniques need dot-matrix gratings. Dot-matrix gratings can diffract an incident laser beam into several diffracted spots and the spots can change their positions fast when the dot-matrix gratings quickly translate. The position changes of diffracted spots can show scanning effects of single line or multiple lines, straight lines or curve lines, and dynamic images. In this paper, some interference and diffraction theories are analyzed first. Then the methods to create dot-matrix gratings with a two-beam writer are introduced. This paper also detailedly introduces the grating-dot encoding methods to simultaneously diffract into several diffracted spots with a laser. Finally, many experiments will be used to check the utility of the proposed diffractive scanning methods.