Proposal of Finishing Method of MLA Mold Applied Sphere Indentation

In this study, the novel finishing method of the Micro Lens Array mold is proposed. This method combines the cutting by a ball-endmill and the finishing by sphere indentation. In the previous step, U-shape grooves intersected at right angle are machined by a ball-endmill. In the following step, the ball tool indents at the intersection between U-shape grooves, consequently, the aiming lens form and the aiming surface roughness are obtained. From the results of the manufacturing experiments of the MLA mold by this method, the following are made clear : The proposed method is effective to suppress the deformation of neighboring lens forms caused by following indentation. The improvement effect of sphere indentation on the finished surface roughness is remarkable in the early stage of indentation. The transcribing deviations are 12μm or less in comparison between the radius of lens form and the ideal value regardless of radii in grooves previously cut. In case of the indentation of neighboring four (2 × 2) lenses, the deviation reduces down to 3μm.