Position encoder using a laser scan beam
AssigneeOptec Co., Ltd.
InventorYoshinori Narutaki
Life of this patent
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Abstract
Known absolute type position encoders have poor resolution due to bits density of tracks formed on an encoding member and mechanical size of sensors opposed to the encoding member for reading absolute position data from the tracks. This invention provides a position encoder comprising a laser scanning type encoding member on which data tracks aligned at equal intervals in a moving direction of a part to be position-measured. A sensor with a single laser beam deflectable along the track is used for reading the position data. High resolution is obtained since it depends upon recorded pitch of tracks. Many data can be recorded on each track, including error correction code for the position code. It improves reliability of the encoder.
Claims9
Apparatus for measuring the positional orientation of an object along a predetermined first path including an encoded member adapted for rigid connection to the object for movement therewith and a substantially stationary reading device adjacent the encoded member, movement of the object along the first path defining a second path on the encoded member corresponding to the relative movement of the reading device adjacent thereto;
- a plurality of position codes spaced along the second path of the encoded device, each code comprising position information uniquely defining a point along the second path, the position information for each code being contained along a first track oriented substantially transversely to the second path, the reading device including means for scanning the track adjacent the reading device whereby the positional orientation of the object along the predetermined first path may be measured.
Apparatus for measuring the positional orientation of an object along a predetermined first path including an encoded member adapted for rigid connection to the object for movement therewith and a substantially stationary reading device adjacent the encoded member, movement of the object along the first path defining a second path on the encoded member corresponding to the relative movement of the reading device adjacent thereto;
- a plurality of position codes spaced along the second path of the encoded device, each code comprising position information uniquely defining a point along the second path, the position information for each code being contained along a track oriented substantially transversely to the second path, the reading device including means for scanning the track adjacent the reading device and means for automatically adjusting the scanning means transverse to the tracks whereby the scanning means may be aligned with the track to be scanned thereby facilitating an accurate determination of the positional orientation of the object along the predetermined first path.
Dependencies are inferred from the claim text.