Developing MgF2 nanoparticles for improved anti-reflection coating on aspherical lenses

In general, MgF2, which is a low-reflective coating material, has a refractive index of 1.38. The refractive index of a single layer of MgF2 is not sufficient for industrial applications. In this study, an anti-reflection MgF2 coating film with low reflectivity and high wear resistance was synthesized to be used as a single layer with a TEOS binder. The prepared anti-reflection coating film was coated in the form of nanoparticles on a curvature lens having an aspherical surface coefficient by spin coating, and the correlation with optical properties was confirmed through particle size measurement. The MgF2 nanoparticle AR coating film was characterized by LDPSA, UV-Vis, SEM and ellipsometry. Mechanical and optical properties were confirmed with a minimum reflectance of 0.1% or less and a low refractive index of 1.24–1.25.

Investigation of Polishing Characteristics for Aspherical Lenses Manufacturing

There were used the spherical lenses in industry conventional for long time, but new types of lenses were created during innovation processes. One type of lenses is aspherical. Two main parameters describing quality of aspherical lenses are accuracy of the form shape and surface roughness. These parameters can be obtained after last operation – polishing. Technical parameters that give the biggest influence to form shape and surface roughness were investigated in this experiment and optimal technical parameters for polishing process were established. Melted quartz ,,UVFS” was used in this research, investigations were carried out according by full factorial design. Five axis CNC machine Schneider SCPA100 was used for polishing and profilometer Nanoscan 855 was used for measurements. After analysis of results it was found out that speed of rotation and penetration depth are the most important factors in polishing process. For getting the best shape it’s necessary to use the smallest chosen values of speed of rotation and penetration depth, for getting the best surface roughness polishing parameters changing conversely. The smallest value of surface roughness Rz was 0.06 µm, and shape deviation was 2.6 µm. Optimal polishing parameters for the best quality of aspherical lenses was provided.

Effective Optical System Assembly Using Ultra-Precise Manufactured References

The present work demonstrates that exactly manufactured references for joining, mounting, and metrology purposes are crucial in the effective assembly of high-quality optical systems. Based on the alignment turning of spherical and aspherical lenses, the proposed approach can be transferred to non-rotational symmetric elements such as prisms, active components (e.g., laser diodes), and freeform mirrors. The complexity of the optical component decides whether on-machine metrology or specific measurement setups need to be used to determine the position and orientation of the references with respect to the optical function. The resulting correction data are considered during the machining process. The subsequent correction cycle realizes mounting and metrology references down to sub-micron precision using diamond-machining techniques. This approach facilitates the assembly of demanding optical systems and even freeform arrangements in a predictable and passive manner. Different machining setups as well as the corresponding metrology approaches are demonstrated, and results are presented for representative components. The effectiveness of the approach is discussed using rotationally symmetrical lens systems and a snap-together freeform mirror system.