METHOD AND APPARATUS FOR MEASURING SURFACE STRUCTURE OF A NEAR-FIELD OBJECT

• Main Authors: LEE KWEN-JIN, PENG MING-TSAN, CHANG CHI-SHEN, HUANG HAI-JO, KUO JI-WEN, WU CHUN-TE, LEE YUANIN, JU JAU-JIU, WANG SHYH-JIER, JENG TZUAN-REN
• Format: Patent
• Language: English
• Published: 18.10.2007
• Subjects: APPLICATIONS OF SCANNING-PROBE TECHNIQUES, e.g. SCANNING PROBEMICROSCOPY [SPM]; INFORMATION STORAGE; INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORDCARRIER AND TRANSDUCER; MEASURING; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS; MEASURING LENGTH, THICKNESS OR SIMILAR LINEARDIMENSIONS; PHYSICS; SCANNING-PROBE TECHNIQUES OR APPARATUS; TESTING

A method for measuring a surface structure of a near-field object is provided. A light source produces at least a first light beam and a second light beam; guiding the first light beam and the second light beam to enter the SIL for interacting with the object surface. This method can be used in, for example, a near-field optical disc storage system, wherein reflection intensities of the first and second light beams are used to measure two distances between the SIL and the optical disc at two positions corresponding to the first and second light beams. A surface structure, such as a tilt angle or an average distance between the disc and the SIL or disc roughness, is obtained by analyzing the above-mentioned positions and distances. The first and second light beams are produced, for example, by a diffraction technology or by a single laser diode with multiple beams.