Patent ID: 8682154
Filing Date: 2014-03-25
Classification: G01D,G02B,G03B

Abstract:
1. A position detection unit for detecting the position of an object to be detected, comprising: a first sensor for outputting a monotone signal, monotonically increasing or decreasing within a predetermined detection range in response to displacement of the object to be detected; a second sensor for outputting two sinusoidal signals of mutually offset phases, varying sinusoidally in response to displacement of the object to be detected; a first memory section for storing monotone signal data, which is the value of the monotone signal relative to the position of the object to be detected; a second memory section for storing max/min data, which is the maximum value and minimum value in each cycle of each sinusoidal signal; and a position computing section; wherein the position computing section identifies the cycle of the sinusoidal signal within which the object to be detected is positioned, based on the monotone signal detected by the first sensor and the monotone signal data stored in the first memory section, and wherein the position computing section calculates the position of the object to be detected within the identified cycle based on the two sinusoidal signals detected by the second sensor and on the max/min data stored in the second memory section, to obtain an absolute position.