| 摘要 |
An apparatus and a method for measuring birefringence are provided to precisely measure phase and path differences of optical products and to measure birefringence only by image processing without having a mechanical driver, by using signal intensity and intensity ratio generated while two different types of short-wave lasers with different frequencies pass through a transparent plastic substrate. An apparatus for measuring birefringence comprises an optical system(10), an amplifier, a terminal(30), an A/D converter(40), a stepping motor(60), and a reference signal processor(50). The optical system is where two different types of lasers are projected by a light source(11) and a signal obtained by phase modulation is detected. The amplifier extracts two types of signal intensities detected by the optical system. The terminal is provided with a stored-program that collects the signal generated by the amplifier and measures birefringence by using the signal intensities and signal intensity ratio. The A/D converter converts the analog signal from the amplifier into a digital signal. The stepping motor rotates a sample substrate(S) included in the optical system. The reference signal processor presents a modulation amplitude of a PEM(Photo-Elastic Modulator,13) of the optical system to the signal collected by the amplifier.
|
