| 摘要 |
<p>A laser instrument of the kind used to detect light reflected from a target which is spaced from the laser instrument, includes a source laser (10) for generating a laser light beam (32) for transmission to the target and a bifocal lens assembly (12) which is retro-directive in nature. The bifocal lens assembly (12) is composed of a lens (14) and a mirror, much smaller in diameter than the lens (14) being attached to the lens (14) for receiving and reflecting the laser light beam (32) onto the optical axis of the lens (14). Respective small diverging and converging (36) lens portions, formed on opposite sides of the lens (14) and in alignment with its optical axis, expand and focus the received laser beam on the target. Respective large diameter converging lens portions (38), formed on opposite sides of the lens about the respective small diameter diverging and converging (36) lens portions and in alignment with the optical axis of the lens (14), collect and focus on a light detector (18) the light being reflected from the target.</p> |
