Rotation quantity measuring method and system
AssigneesRicoh Company, Ltd., Hiroshi Kobayashi, Haruhiko Machida
InventorsHiroshi Kobayashi, Haruhiko Machida, Jun Akedo, Hiroyoshi Funato
Life of this patent
Estimating the term…
Abstract
A rotation quantity measuring method and system measures a rotation quantity of an object body. The rotation quantity is measured by irradiating a light from a light source on a grating pattern which is formed on a peripheral surface of a cylindrical body which rotates integrally with the object body, and detecting a shadow picture pattern which is generated by a reflected light received from the grating pattern based on a diffraction caused by the grating pattern. Then, the rotation quantity of the object body is measured based on a movement of the shadow picture pattern as the object body rotates.
Claims20
A rotation quantity measuring method for measuring a rotation quantity of an object body, said rotation quantity measuring method comprising the steps of:
- irradiating a light from a light source on at least one grating pattern which is formed on an outer peripheral surface of a cylindrical body which rotates together with the object body, said grating pattern being made up of gratings which are formed with a constant pitch and which are oriented in a direction which coincides with a rotational direction of said cylindrical body;
- and
- detecting a shadow-like diffraction pattern which is generated by a reflected light received from the grating pattern based on a diffraction caused by the grating pattern and measuring the rotation quantity of the object body based on a positional shift of the shadow-like diffraction pattern as the object body rotates.
A rotation quantity measuring system for measuring a rotation quantity of an object body, said rotation quantity measuring system comprising:
- a cylindrical body which rotates together with the object body;
- at least one grating pattern formed on an outer peripheral surface of said cylindrical body, said grating pattern including gratings which are formed with a constant pitch and which are oriented in a direction which coincides with a rotational direction of said cylindrical body;
- light source means for emitting light and irradiating the light on said grating pattern;
- and
- detecting means for detecting a shadow-like diffraction pattern which is generated by a reflected light received from said grating pattern based on a diffraction caused by said grating pattern and measuring the rotation quantity of the object body based on a positional shift of the shadow-like diffraction pattern as the object body rotates.
Dependencies are inferred from the claim text.