Laser beam receiving unit
AssigneesRohm Co., Ltd., Seiko Epson Corporation
InventorsNaotaro Nakata, Hironori Endo
Life of this patent
Estimating the term…
Abstract
A light receiving unit comprises a condenser lens (11) which converges laser beam and a light receiving unit (12) which receives the incident beam converged by the condenser lens. The light receiving element is formed, such that the light receiving portion thereof has an area of 2 mm2 or less and disposed at the side of the condenser lens than the point P where the beam is converged by the condenser lens and at the position more apart from the condenser lens than the position F of the focal distance of the condenser lens. As a consequence, a light receiving unit which detects the laser beam can be obtained, the light receiving unit enabling it possible to always receive the laser beam regardless of a little eccentricity of a laser source while the speed of response is raised.
Claims6
A laser beam receiving unit which receives the laser beam to detect a detection object passing through said laser beam comprising:
- a condenser lens which converges said laser beam;
- and
- a light receiving element which receives the incident beam converged by said condenser lens,
- wherein said light receiving element is formed, such that the light receiving portion thereof has an area of 2 mm2or less, and is disposed on one side of said condenser lens closer to the condenser lens than a point where said laser beam is converged by said condenser lens, and is disposed at a focal point of said condenser lens or at a position further from said condenser lens than the focal point.
Dependencies are inferred from the claim text.