Patent ID: 8945438
Filing Date: 2015-02-03
Classification: B29C,G02B,G11B

Abstract:
1. A mold for forming a lens, the lens being made of resin and the lens having a first lens surface and a second lens surface, the second lens surface formed on a reverse side of the first lens surface, the metal mold comprising: a first inner metal mold which forms the first lens surface and a first flat surface portion, the first flat surface portion being formed around an outer periphery of the first lens surface, and the first flat surface portion being a ring-shaped surface perpendicular to an optical axis of the lens; a first outer metal mold which forms a second flat surface portion, the second flat surface portion being formed around an outer periphery of the first flat surface portion and positioned closer to a side of the second lens surface than the first flat surface portion, and the second flat surface portion being a ring-shaped surface perpendicular to the optical axis of the lens; a second inner metal mold which forms the second lens surface and a third flat surface portion, the third flat surface portion being formed around an outer periphery of the second lens surface, and the third flat surface portion being a ring-shaped surface perpendicular to the optical axis of the lens, and a second outer metal mold which forms a fourth flat surface portion, the fourth flat surface portion being formed around an outer periphery of the third flat surface portion and positioned closer to a side of the first lens surface than the third flat surface portion, and the fourth flat surface portion being a ring-shaped surface perpendicular to the optical axis of the lens, wherein a first protruded portion which forms a first concaved portion on the lens is formed all around an outer periphery of the first inner metal mold, the first concaved portion serving as clearance for a burr at a boundary of the first outer metal mold and the first inner metal mold when the lens is formed, wherein a second protruded portion which forms a second concaved portion on the lens is formed all around an outer periphery of the second inner metal mold, the second concaved portion serving as clearance for a burr at a boundary between the second outer metal mold and the second inner metal mold when the lens is formed; the first protruded portion has a tapered surface that projects farther from the first inner metal mold as the tapered surface of the first protruded portion extends farther from the optical axis of the lens; and the second protruded portion has a tapered surface that projects farther from the second inner metal mold as the tapered surface of the second protruded portion extends farther from the optical axis of the lens; a tip of the first protruded portion nearest to the second lens surface is positioned on the first lens surface side with respect to the second flat surface portion in the optical axis direction; and a tip of the second protruded portion nearest to the first lens surface is positioned on the second lens surface side with respect to the fourth flat surface portion in the optical axis direction.