Device and method for measuring glass thickness by adopting sinusoidal modulation multi-beam laser heterodyning of Doppler galvanometer

• Main Authors: WANG CHUNHUI, GAO LONG, SHAO WENMIAN, LI YANCHAO, QU YANG
• Format: Patent
• Language: Chinese; English
• Published: 23.11.2011
• Subjects: MEASURING; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS; MEASURING LENGTH, THICKNESS OR SIMILAR LINEARDIMENSIONS; PHYSICS; TESTING

The invention discloses a device and a method for measuring glass thickness by adopting sinusoidal modulation multi-beam laser heterodyning of a Doppler galvanometer, and belongs to the technical field of micro displacement detection. The device consists of a laser device, a polarizing beam splitter (PBS), a quarter wave plate, a galvanometer, a planar reflector, a glass plate with to-be-measuredthickness, a converging lens, a photoelectric detector and a signal processing system. The method comprises the following steps of: turning on a driving power supply of the galvanometer so that the galvanometer starts simple harmonic vibration; meanwhile, turning on the laser device; and starting measurement, in the measurement process, continuously acquiring electrical signals output by the photoelectric detector through the signal processing system, processing the acquired difference frequency signals, and acquiring the thickness d of the glass plate with to-be-measured thickness according to the relationship fp=Kpd