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Title:
METHOD AND APPARATUS FOR OPTICALLY MEASURING DISPLACEMENT AMOUNT
Document Type and Number:
Japanese Patent JPH07270186
Kind Code:
A
Abstract:

PURPOSE: To provide a method for optically measuring a displacement amount which is hard to be affected by a stain and a break of a periodic pattern on the surface of a scale and a light from outside.

CONSTITUTION: At least one-dimensional image sensor having 8 or more pixels on a photodetecting element is used. Dividing means 5, 6 and 7 equally divide a periodic image pattern of a plurality of cycles received by the image sensor to four or more segments for a pixel count of the image sensor corresponding to one cycle at an ideal state. Counting means 8-11 sequentially count and accumulate output times of the image sensor for every one of equally divided four or more segments per one cycle, for respective segments for a plurality of cycles of the periodic image pattern. Whether the periodic image pattern passes is detected from whether the accumulated time for each segment compared by comparison means 12, 13 is larger or smaller. A relative displacement amount and a relative displacement direction of a scale and the image sensor are detected in this manner.


Inventors:
KOYAMA KATSUYA
NISHIOKA KEIICHI
Application Number:
JP1994000064197
Publication Date:
October 20, 1995
Filing Date:
March 31, 1994
Export Citation:
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Assignee:
KEYENCE CO LTD
International Classes:
G01B11/00; G01D5/244; G01D5/245; G01D5/36; (IPC1-7): G01D5/36; G01B11/00; G01D5/245
Attorney, Agent or Firm:
河野 登夫



 
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