Patent ID: 8304063

Claim:
A diamond-like carbon film comprising at least two layers, one layer being a lower layer of diamond-like carbon closest to a substrate and the other layer being an upper layer of diamond-like carbon placed on the lower layer and being further from the substrate, wherein the lower layer is formed by physical vapor deposition and has a hardness no lower than 20 GPa and no higher than 45 GPa, a Young's modulus no lower than 250 GPa and no higher than 450 GPa, and a thickness no smaller than 0.2 μm and no larger than 4.0 μm, and the upper layer is formed by chemical vapor deposition and has a hardness no lower than 5 GPa and lower than 20 GPa, a Young's modulus no lower than 60 GPa and no higher than 240 GPa, and a thickness no smaller than 1.0 μm and no larger than 10 μm, and wherein said diamond-like carbon film has a plastic deformation under a load of 1000 mN of 1.58-1.87 μm.