| 摘要 |
PROBLEM TO BE SOLVED: To provide a rotation angle detection device which is compact and has a simple structure.SOLUTION: A rotation angle detection device includes: a shaft part space 4 formed in a rotary shaft 1; a bearing part space 5 formed in a bearing part 3; a first condenser lens 7 accommodated in the shaft part space; a second condenser lens 8 provided in the shaft part space; a detection pattern 11 provided at a focus position of the first condenser lens or the second condenser lens; an image sensor 12 provided at the focus position of the first condenser lens or the second condenser lens; and an arithmetic unit 14 for calculating an angle displacement of the rotary shaft on the basis of a signal from the image sensor. The detection pattern has an angle detection pattern and a reference indication pattern, and the arithmetic unit extracts a frequency component by scanning the whole circumference of a track in a projection image of the detection pattern at a predetermined radius by using the angle detection pattern as a center, and calculates the angle displacement of the rotary shaft on the basis of the number of frequencies corresponding to the phase difference of the rotary shaft and the position replacement of the reference indication pattern. |
