How to ensure the precise alignment of cemented prism in high-precision optical systems?
Publish Time: 2025-01-15
In high-precision optical systems, it is crucial to ensure the precise alignment of cemented prisms, because any slight deviation in alignment may cause light offset, scattering or degradation of system performance.1. High-precision optical toolingPrecision positioning fixture: Use high-precision optical positioning fixtures to ensure the precise positioning of prisms during gluing. The fixture should have fine-tuning functions to allow adjustment in multiple degrees of freedom.Calibration reference: Set precise calibration references on the fixture, such as optical reference plates or precision positioning pins, to ensure position consistency during each clamping.2. Optical alignment technologyInterferometer: Use high-precision instruments such as laser interferometers or Michelson interferometers to monitor the alignment accuracy of prisms in real time. Small deviations in the surface and angle of the prism can be detected by changes in interference fringes.Laser alignment: Use a laser beam as a reference light and adjust the alignment of the prism by observing the reflection of the laser beam on the prism surface. The laser beam should be able to form a clear focus on the prism surface, and the reflected light should be aligned with the incident light.Common optical path calibration: During the bonding process, the common optical path calibration technology is used to ensure that the optical paths of the two prisms are completely overlapped. By adjusting the position and angle of the prism, the propagation path of the light between the two prisms is consistent.3. Fine-tuning mechanismMulti-axis fine-tuning platform: Use a multi-axis fine-tuning platform to allow fine-tuning on the X, Y, Z axes and tilt angle. The platform should have a high-resolution feedback control system to ensure the accuracy of fine-tuning.Piezoelectric ceramic fine-tuning: In some high-precision applications, piezoelectric ceramic fine-tuning devices are used to achieve sub-micron position adjustment by applying small voltage changes.4. Optimization of bonding processLow shrinkage glue: Select optical glue with low shrinkage characteristics to reduce the impact on the alignment state of the prism during the glue curing process. Commonly used optical glues include epoxy resin and UV curing glue.Precise control of the curing process: For heat-curing glue, use precise temperature control equipment to ensure uniform curing of the glue and avoid prism position deviation caused by uneven curing. For UV-curing glue, use a high-intensity UV light source to ensure that the glue is completely cured in a short time.Vacuum environment: During the gluing process, use a vacuum environment to remove air bubbles between the fixture and the prism to ensure uniform distribution of the glue and avoid the influence of bubbles on the alignment accuracy.5. Quality inspection and feedbackReal-time monitoring: During the gluing process, the alignment status of the prism is monitored in real time, and the position and angle of the prism are dynamically adjusted through the feedback control system to ensure the alignment accuracy.Post-processing inspection: After the gluing is completed, use high-precision inspection equipment such as microscopes, interferometers or autocollimators to detect the alignment accuracy of the cemented prism. For the deviations found, make necessary corrections.System integration test: After the optical system is integrated, perform an overall performance test to ensure that the alignment accuracy of the cemented prism meets the system requirements. Further optimize the alignment status by adjusting the system parameters.Through the above method, the precise alignment of cemented prism in the high-precision interferometer system was successfully achieved, ensuring the performance and resolution of the system.
