Patent ID: 7391207

Claim:
A rotation angle detector for detecting a rotation angle of a magnetic field comprising: a plurality of Hall elements on one side of a semiconductor substrate for outputting an output signal having a different phase respectively induced by the magnetic field; and a plurality of through holes arranged in an area adjacent to an outside of the ring shape of the Hall elements on the semiconductor substrate, wherein a portion of the output signal from one of the plurality of Hall elements that has a substantially linear output characteristic relative to the rotation angle of the magnetic field is selectively used to detect the rotation angle, wherein the magnetic field rotates in a plane in parallel with the semiconductor substrate, wherein the Hall element is either of a vertical type and a slant type, wherein the Hall elements are disposed equiangularly in a ring shape around a rotation center of the magnetic field, wherein the number of the Hall elements is equal to or greater than three, wherein the number of the Hall elements is equal to or smaller than twelve, wherein the semiconductor substrate is made from a silicon substrate having {100} crystal face orientation, wherein the Hall elements are aligned to a <011> direction and a <011> direction relative to the rotation center of the magnetic field, wherein the through holes are arranged in rotationally symmetrical positions around the rotation center, and wherein a signal process circuit for switching signals from the plurality of Hall elements is positioned in an area inside of the ring shape of the Hall elements.