Patent ID: 8308016

Claim:
A non-stick cooking utensil having inner walls, wherein the inner walls have a non-smooth surface with convex units, the height (h) of the units ranges from 20 μm to 999 μm and the projection area of the convex units on the surface of the inner wall ranges from 314 μm 2 to 783431 μm 2 , wherein each convex unit has a spherical crown shape that includes a spherical portion on top of a cylindrical portion, and a bottom circle diameter (φ) of the spherical crown ranges from 20 μm to 999 μm, wherein the distribution density of the convex units, defined as the ratio of the total geometrical projection area of the convex units on the base body surface of the inner wall to the area of the base body surface, ranges from 10% to 60%; and wherein an oxidized surface film is formed on the surfaces of the non-smooth convex units.