Optical lens design and engraving technology

In the lenticular optical lens plastic/polymer processing industry today, the current old method of supplying lenticular/optical extruding cylinders consists of applying a soft copper base plating onto a steel green-based cylinder surface, which is then diamond turned and engraved. After the lenticular engraving, post chrome thin-flash plating is applied on top of the copper engraved plating, to help protect the soft copper finish underneath.

The advantageous elliptical lens design and roll mould method developed by Jacobsen Lenticular Tool & Cylinder Engraving Technologies (JacoTech) over the old industry method of copper plus post chrome plating provide solutions for optically-based cylindrical polymer/plastic materials processing, including the manufacturing of micro-structured optical-quality roll-surface engraved mould components used for the management and control of light.

Disadvantages of the old method
Since copper metal has a very soft Rockwell hardness level of approximately 220 Vickers, it damages easily, especially during the engraving process (tearing) or from handling within the extruding facility. Copper also begins to oxidise (change colour) immediately after engraving and has to be post plated quickly. Furthermore, it is easily susceptible to staining, which can then transfer into the lenticular lens material as a stain or artefact.

Post chrome flash plating is very thin (5 microns), which offers very little protection from nicks, scratches and handling of the cylinder. Chrome plating has inherent micro-cracks within the final plated finish and chrome does not deposit evenly across the cylinder width, therefore altering the quality of the lenticular lens materials across the master lenticular roll width.

Post chrome flash plating can detach itself from the copper engraved plating after short use, especially when extruding with acidic resins, such as PVC. This condition can render the cylinder useless and then it must be re-worked. Extruder production ceases and causes unnecessary delays and more expenses for extruders.

Post chrome flash plating can alter the intended optical lens design, by adding an undesired thickness to the copper engraved lenticulars. Plus, the addition of chrome plating on top of the copper engraved lenticular changes the profile to a more rounded undesired profile as compared to required (knife like sharp peaks). The chrome post-plated lenticular profile develops a “land area” compared to a “knife-like sharp peak” lenticular groove. This can change the intended optical lens design negatively, creating possible optical quality problems when viewed as a 3D display, cell phone, computer or LCD/LEDTV screen.

Advantages of the new method
With 55 Rockwell C hardness, JacoTech proprietary nickel/alloy plating is harder and will not damage as easily as copper. After engraving, the plating is also not susceptible to staining and will not transfer stains into the lenticular lens material, assuming the cylinder surface is cleaned properly.

The single-ply integrated plating requires no post plating and is applied heavily to the green-based cylinder for best durability, meaning that it will not detach itself from the base. The plating also offers much better protection from nicks, scratches or from normal handling of the cylinder compared to soft copper; has an excellent surface finish, and is even across the entire cylinderZoom Kobe Elite High