Patent ID: 10838361

Abstract:
A Volume Bragg grating (VBG) is placed in the back of a collimating lens, the incident angle between exposure light beam and the Volume Bragg grating is equal to the Bragg angle of the Volume Bragg grating. A photodetector is placed in the −1 grade transmission diffraction light path of the Volume Bragg grating which the exposure light beam is emitted to. The pinhole filter is moved back and forth along an optical axis and the reading of the photodetector is observed in real time. When the reading of the photodetector is maximum, fix the pinhole filter and keep the distance between the first pinhole filter and the first collimating lens a constant. The method for adjusting the self-collimation optical path is provided, using the Volume Bragg grating to detect the parallelism of self-collimation light and substituting for a traditional Moire pattern adjustment method.