Research On Beam-splitting Parallelism And Efficiency Detection For Multi-axis Interferometer

In recent years, because of its high precision, fast and wide measuring range, etc. advantage, laser interference measurement technique widely used in scientific research and industrial production, especially multi axis laser interferometer with photoetching machine for microelectronic processing equipment and high-end ultra precision machining equipment, in the heart of the system. Multi axis laser interference instrument integrate many optical devices in various interference mirror group is the core components, through on the optical integration, reducing the volume of the system and avoid the alignment process, bring convenience to the application, but interference mirror group after setting is not easy to adjust, assembly type process will introduce the light and parallel light efficiency is not ideal to become the major source of error of laser interferometry in instrument. Limited the precision of angle measurement and length measurement of laser interferometer.This topic mainly aiming at the above problems, the interference optical lens group are not parallel and divided into light efficiency is not ideal method to study; the discussion of the advantages and disadvantages of existing mirror component parallel light detection and optical efficiency detection method based on. The based on differential from the focus error detection of parallelism detection method, and based on unsaturated state CCD light intensity detection is divided into light efficiency detection method, the establishment of relevant measurement model proposed can take into account the overall optical efficiency of detection scheme with parallel and, eventually build detection system and complete the detection of lens optical parallelism and optical efficiency of two parameters. The main research contents are as follows:1. A new method for parallelism measurement is proposed, aiming at the parallelism between the optical axes of a multi axis interferometer. Use tow CCDs place on the symmetric place of focal plane to get the information of the space position of beam, and calculation parallelism. A new method for light splitting efficiency is proposed too, and set up a model which can be used for multi axis interferometer. Final, a system which can measure parallelism and light splitting efficiency is designed.2. CCD axial position error, angle error, position error of the optical prism makes a systematic analysis of the influencing rules of detection of parallel, obtained by parallel detection error of the device installation error tolerance, the parallelism error is less than 2%, the position error of CCD(-0.01 mm, 0.01mm), angle error(- 10 degrees, 10 degrees); at the same time that optimal system installation scheme.3. Completed the system hardware and software design, aiming at the establishment of detection model and measuring accuracy and measuring range demand, one by one the selection of key components, and designed the mechanical structure of the optical prism, the CCD assembly; using Lab VIEW to design the software system, including control, acquisition and data processing function, can realize the balance measurement of parallel and sub light efficiency of multi axis.4. The measurement system is tested and analyzed, parallelism measurement and autocollimator are compared, system stability is 0.1″and resolution is 0.2″, the repeatability of parallelism measurement is 0.04″ and the system repeatability of light splitting efficiency is 0.4%.