optic axis

Từ điển WordNet v3.1 - WordNet Dictionary

noun

1. in a doubly refracting crystal, the line in the direction of which no double refraction occurs
- a crystal may have either one or two optic axes
• Hypernyms:
axis
2. a line that passes through the center of curvature of a lens so that light is neither reflected nor refracted
- in a normal eye the optic axis is the direction in which objects are seen most distinctly
• Syn:
principal axis
• Hypernyms:
axis