| 摘要 |
PURPOSE:To make the detection of rotating angle with high accuracy, without malfunction due to improper contactness,by detecting an optical pattern on an external circumference of a rotating body with a photo detecting means consisting of a linear sensor in the form of a digital signal. CONSTITUTION:An optical pattern 3 is formed on the external circumference of a rotating body 1 and a reflected light on the external circumference of the rotating body 1 out of illuminated light beam passes through an image forming means 6 and is detected on the photo detecting surface of a photo detecting means 7. A detection controlling means 8 contols the means 7. As the means 6, for example, a SELFOC lens array consisting of linear lenses made of optical fibers is used, and as the means 7 a semiconductor linear sensor is used. Both ends P and Q of a pattern 2 are located on a generating line along the axial direction on the external circumference of the body 1 and the positions are on a straight line with expansion and the planes have different reflecting ratio from that of the external circumference surface. A clock signal CP and a start pulse SP are applied to the means 7 and a counter 14 can obtain a signal proportional to a rotating angle theta with a photo detecting signal SO. |
