The Fabrication Of Fine Lens Arrays By Laser Beam Writing

Lenticular arrays with near diffraction-limited performance have been generated by laser beam writing. A photoresist film is exposed in a line raster mode by scanning under an intensity-modulated focused laser beam; subsequent development of the resist film produces the desired lenticular relief profile. The writing of exposure patterns by raster scanning is analyzed, and it is shown that very precise positioning of each raster line is required to avoid unwanted modulation terms. A low cost xy positioning table with better than 20 nm dynamic positioning accuracy was constructed to satisfy this requirement, and has been used to generate high quality fine lenticular arrays with lenslets of widths down to 20 μm and relief depths up to about 4 μm.