2019 Volume 60 Issue 702 Pages 195-202
A new technique of the three-dimensionl photolithography is introduced for fabricating the texturing reliefs on the cylindrical roll surface. The advantage of the photolithography realizing the high throughput against the fine arbitrary pattern shape is effectively applied on the roll surface by introducing a sheet with a polyvinyl alcohol layer. After the wet etching of the roll steel and the electro-polishing, the convex ring arrays are obtained. All designed patterns of the 4-different ring arrays having the corresponding pitches of 300-900 dpi are obtained. The ring outer diameters are 26-76 µm and their array pitches are 28-84 µm in design. The pattern smaller than 50 µm is said to be undetectable for the naked eye. The minimum ring width is 7 µm in design. Its average in real is 2.75 µm due to the under-etching of the roll metal. Such fine texture pattern on the roll has the smooth profile without the spike, which is occurred when the conventional shot peening is applied. The ring pattern is properly transferred to the aluminum plate without the tear. The pattern sizes on the roll and on the transferred aluminum plate agree reasonably each other with the standard deviation less than 3 µm in size. Since the finer ring pattern array can generate the larger light diffraction effect, the incident illumination light shows the wider reflected and diffracted optical angles. The overall surface shows the frosted white color tone. Overall, the combination of the techniques of the photolithography and the mechanical rolling are demonstrated.
