Apparatus and method for measuring displacement, method of making die for molding optical element, and optical element
AssigneeCanon Kabushiki Kaisha
InventorTeppei Agawa
Life of this patent
Estimating the term…
Abstract
A beam splitter splits a laser beam emitted from a laser light source into a first laser beam that travels toward an object and a second laser beam. The second laser beam is received by a second photodetector. The second photodetector is positioned such that the light quantity of the second laser beam incident on the second photodetector is equal to that of the first laser beam incident on a first photodetector. A position calculator calculates displacement of the object relative to the laser light source on the basis of the difference between an output of the first photodetector and an output of the second photodetector.
Claims14
A displacement measuring apparatus for measuring displacement of an object, comprising:
- a laser light source;
- a beam splitter disposed between the laser light source and the object, the beam splitter being configured to split a laser beam emitted from the laser light source into a first laser beam that travels toward the object in a first direction and a second laser beam that travels in a second direction different from the first direction;
- a first photodetector configured to receive the first laser beam;
- a second photodetector configured to receive the second laser beam;
- and
- a calculating unit configured to calculate displacement of the object on the basis of an output of the first photodetector which has received the first laser beam blocked by the object and an output of the second photodetector which has received the second laser beam not blocked by the object.
A method of measuring displacement of an object, the method comprising:
- splitting a laser beam emitted from a laser light source into a first laser beam that travels toward the object in a first direction and a second laser beam that travels in a second direction different from the first direction through a beam splitter disposed between the laser light source and the object;
- and
- measuring displacement of the object on the basis of an output of a first photodetector which has received the first laser beam blocked by the object and an output of a second photodetector which has received the second laser beam not blocked by the object.
Dependencies are inferred from the claim text.