Design And Verification Technology Of The Phase-only Optical Anti-counterfeiting Mask

With the rapid development of the information technology, identity authentication and certificates anti-counterfeiting technology has become a priority which has to be resolved and improved in the field of information security. The phase-only optical anti-counterfeiting mask design method, which is discussed in this thesis, can encode the anti-counterfeiting mark to transparent optical mask. It has advantages such as hard to be perceived by CCD, difficult to be copied and provides a new development thought in identity verification and certificates anti-counterfeiting. In this thesis, on the one hand, a detailed discussion in phase-only optical anti-counterfeiting mask iterative design method is made, meanwhile we do a plenty of researches and explorations focused on the experimental simulation and verification. Through testing, satisfied experimental results are received. The main research contents include the following aspects:(1) Make a detailed analysis and discussion to several representative iterative design methods for phase-only optical anti-counterfeiting mask and through computer simulation and verification, making a comparison of the quality of the kinoforms and reconstruct images got by different iterative algorithms, which provides a theoretical and technical basis for the computer aided design of the phase anti-counterfeiting mask.(2) Expand the laboratory simulation technology of the phase encoding components. Based on the liquid crystal screen LCX026BLT, completing the phase-only LCSLM's design and making. The whole system's printed circuit board is drawn by the Altium designer software, by welding and debugging, the entire board passes the test and works in a stable condition.(3) Use the Mach-Zehnder interferometer to measure the phase and intensity modulation characteristics of the phase-only LCSLM. A satisfied phase modulation curve is got, the maximum phase modulation can be 1.83π, and the intensity's variations is less than 10%, these verify the design of the phase-only LCSLM.(4) By loading the kinoform which is got by iterative algorithm to the phase-only LCSLM, then through the optical experiment, the desired image is received. The result verifies the whole system's design.