DISTANCE MEASURING DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a distance measuring device capable of avoiding the worst value of an error.SOLUTION: An irradiation device irradiates a measurement object with irradiation light L1 while modulating an intensity of the irradiation light L1 by a substantially square wave. A light receiving element receives light reflected by the measurement object among the irradiation light L1 as reflection light. Each of a first period T1 to a third period T3 has the same period lengthΔT. The first period T1 starts with a predetermined time difference at the rising time of the irradiation light L1. The second period T2 starts with the time difference at the falling time of the irradiation light L1. The third period T3 is a period between the first period T1 and the second period T2. The calculation unit calculates a time on the basis of a formula represented byΔT*(a3-a1+a2)/(2*a3) using a first reflection light quantity a1, a second reflection light quantity a2, and a third reflection light quantity a3 obtained by receiving reflection light L2 in each of the first period T1 to the third period T3, and calculates a distance up to the measurement object on the basis of the time.