Watch crystal including a lens and manufacturing method for such a lens
AssigneeComadur SA
InventorGuy Delabre
Life of this patent
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Abstract
The invention concerns a watch crystal (1) made of hard mineral material, in particular a crystalline material such as corundum, sapphire or spinel, including a non-circular optical lens (4) shaped in the thickness of the material of the crystal. The lens is formed by machining and polishing a recess (5) preferably situated in the lower face (3) of the crystal. Its contour can have reentering angles, and can be for example rectangular. The machining is effected by means of a brush which hits the bottom of the recess with the addition of a polishing medium.
Claims8
A watch crystal made of a material selected from the group consisting of corundum, sapphire or spinel, including an optical lens shaped in the thickness of the material of the crystal, wherein the lens has a non-circular contour in plane.
A watch crystal consisting of corundum, sapphire or spinel, including an optical lens shaped in the thickness of the material of the crystal, wherein the lens has a non-circular contour in plane.
Dependencies are inferred from the claim text.