A study on manufacturing technology for an inclined polygon mirror

Generally, the core component of small precise optical device demands high accuracy of manufacturing processes. Although, the geometry of it is simple, the manufacturing technique to materialize is categorized as the ultra precision machining and it must be done with the specialized machines and by the trained operator. Typical examples of small precise optical device are laser printer and phone camera. The shape is very simple but required manufacturing technology is very difficult. It belongs to fine precision machining technique and needs an ultra precision machining center and an assignment researcher. Laser printers and phone cameras are representative examples in small precise optical device. Recently, small sized display device is being developed and has an inclined polygon mirror as core part. The inclined polygon mirror is different with the previous polygon mirror in the point of view that it has a variety of reflection angle. With the result that, multi lines were achieved at screen. It could not be fabricated with conventional machine for a typical polygon mirror. It was manufactured in the process of fly-cutting with Al material on which was coated electroless-Ni for enhancement of hardness. Owing to process of polishing has bad influence on reflection angle, the inclined polygon mirror must be only fabricated with fly-cutting and have surface roughness Rmax = 10 nm and form error Ra = λ/10 (λ = 632 nm).