| 摘要 |
PROBLEM TO BE SOLVED: To provide a method of forming an optical element having a mark.SOLUTION: A method involves irradiating at least a portion of a surface of the optical element with laser radiation, thereby forming a plurality of elongated grooves 11 in at least the portion of the surface of the optical element, which are each aligned substantially parallel with a common longitudinal direction 17 that extends from a center point of the plurality of elongated grooves 11. The plurality of elongated grooves 11 together define a mark 3. A clear film is formed over at least the portion of the surface of the optical element and the plurality of elongated grooves 11. Depending on the orientation of a source of electromagnetic radiation relative to the common longitudinal direction of the grooves 11 when the electromagnetic energy source is viewed through the optical element, the mark 3 is either observable or unobservable.SELECTED DRAWING: Figure 1 |
