Transparent and scratchproof watch crystal and watch case fitted with such a crystal

• US 6,111,821 A
• Filed: 01/14/1998
• Issued: 08/29/2000
• Est. Priority Date: 01/15/1997
• Status: Expired due to Term

• Current Assignee: Montres Rado S.A.
• Original Assignee: Montres Rado S.A.
• Inventors: Bach, Michael
• Primary Examiner(s): MISKA, VIT W
• Application Number:
  US09/007,042
• Time in Patent Office: 958 Days
• Field of Search: 368/276, 368/280, 368/294-296, 423/446, 427/249, 427/255.7
• US Class Current: 368/280
• CPC Class Codes: G04B 39/006 out of wear resistant material, e.g. sapphire

Abstract

A transparent and scratchproof watch crystal, characterized in that it is made of polycrystalline diamond. The invention also concerns a watch case fitted with such a watch crystal.

Claims

1. A transparent and scratchproof watch crystal made of polycrystalline diamond.

2. A watch crystal according to claim 1, wherein it has a non flat shape.

3. A watch crystal according to claim 1, wherein it is partially spherical.

4. A watch crystal according to claim 1, wherein it is partially cylindrical.

5. A watch crystal according to claim 1, wherein it has a thickness of between 0.5 and 2 mm.

6. A watch case including a middle part and a back cover, wherein it further includes at least one crystal according to claim 1.

7. A method of providing a watch crystal comprising:

making the crystal of transparent polycrystalline diamond; and

installing the crystal in a watch case.

8. A method according to claim 7, wherein the crystal has a thickness of between 0.5 and 2 mm.

9. The use of transparent polycrystalline diamond as a watch crystal having a thickness of between 0.5 and 2 mm.