Method of producing a die forming lens fisheye steps
US5308200A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 8, 1992 |
| Grant date | May 3, 1994 |
| Priority date | — |
| Expiry date | Dec 8, 2012 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T409/303808
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A method of producing a die for use in forming fisheye steps in an automobile lens having both straight and curved portions. The plurality of fisheye steps formed on the curved portion of the lens are divided into generally parallelogram-like sections. The die comprises plural concave portions that are arranged to form the fisheye steps when applied in a lens forming process. In the die producing method, the boundary lines between concave portions corresponding to the respective fisheye steps are connected to produce approximately a straight line, to thereby improve an appearance of the fisheye steps. Further, the concave portions that are divided by longitudinal lines extending in a first direction and lateral lines obliquely intersecting the longitudinal lines and extending in a second direction are produced by NC machining using an end mill. The end mill is controlled to have a locus generally in parallel with the longitudinal lines, in which vector control is added when the end mill passes a start side lateral line that is expected to become a boundary between the concave portions and passes an end side lateral line to enter the next concave portion so that the locus of the end…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.