Manufacturing method for light guide body
Disclosed is a manufacturing method for a light guide body which can prevent light leakage reliably even when the light guide body is formed by injection molding. The method for manufacturing a light guide body includes the step of forming roughness Ra of a surface of the light guide body to equal to/less than 1.0 μm, and step heights on the surface to equal to/less than 10 μm, by means of injection molding.
1 . A method for manufacturing a light guide body, comprising:
forming roughness Ra of a surface of the light guide body to equal to/less than 1.0 μm, and step heights on the surface to equal to/less than 10 μm by means of injection molding.
2 . The method according to claim 1 , further comprising:
forming both ends of the light guide body to tapered shapes having an angle from 3 to 30 degrees.
3 . The method according to claim 1 , further comprising:
subjecting the surface of the light guide body to a lapping process as a surface finishing process.
4 . The method according to claim 1 , further comprising:
dipping the light guide body into a paint, solvent or molten resin as a surface finishing process.
5 . The method according to claim 1 , further comprising:
forming the light guide body to a sheet shape.
6 . The method according to claim 1 , further comprising:
forming the light guide body to a rectangular shape.
7 . The method according to claim 1 , further comprising:
forming the light guide body to a cylindrical shape.
8 . An injection molding die comprising:
a first molding die having a first cavity; and
a second molding die having a second cavity;
the first and second cavities facing each other, and forming outer dimensions of a light guide body;
each of the first and second cavities having a surface with roughness Ra of equal to/less than 1.0 μm, and with step heights of equal to/less than 10 μm.
9 . The injection molding die according to claim 8 ,
wherein the surface of each of the first and second cavities is subjected to a lapping process.
10 . The injection molding die according to claim 8 , further comprising an ejection pin in the first molding die, for ejecting a light guide body from the first molding die toward the second molding die, when the first and second molding dies are separated from each other.
11 . The injection molding die according to claim 8 ,
wherein each of the first and second cavities has tapered ends with an angle from 3 to 30 degrees.
12 . The injection molding die according to claim 8 ,
wherein each of the first and second cavities has a sheet shape.
13 . The injection molding die according to claim 8 ,
wherein each of the first and second cavities is rectangular in shape.
14 . The injection molding die according to claim 8 ,
wherein each of the first and second cavities is cylindrical in shape.