The lenses are clamped into spring rings that have a magnetizable part. The spring ring with the lens is mounted into bearing supports on the dome segment. The spring ring with the lens is turned over when it passes the magnetic field of an electromagnet during the slow rotation of the dome. By reversing the direction of the dome rotation the spring ring with the lens can be turned back over. Lens and lens holder lay stable at fast rotation speed of the dome during the coating procedure.
Conventional flip over devices are often not used for ophthalmic lens AR coating because of several disadvantages such as lowering the machine (dome) capacity due to additional space required in the vacuum chamber and on the dome and also system complexities. Therefore, lens flip over has been done manually outside the vacuum chamber for decades.
The innovative Magnetic Auto Flip Over establishes an automatic turn-over device as an add-on to a vacuum coating machine which achieves the following improvements:
1. Increase of throughput by reducing process time while keeping the lens capacity the same.
2. Reduction of labour time for a two side coating work flow by eliminating manual work steps.
3. Save consumable by using them more efficiently.
Based on minimalist and sophisticated modification of commonly used equipment it fits into established working procedures.
New coating possibilities
Automatic flip over of lenses or any other objects offers new chances for coating application.
To save time and labour costs the anti-reflex layer stack is applied to one side first and then to the second side of the object. With the automatic turn-over it becomes efficient to double side coat the object layer by layer. Thereby, new coating features might become possible in the future.