Two-dimensional code reading device, two-dimensional code reading method, method of controlling manufacturing history information of member having substantially circular section orthogonal to the central axis thereof, and method of manufacturing the member using the control method

摘要

A two-dimensional code reading device 20 is provided with image pickup device 22 which receives light reflected from either of a first inclined portion 12 and a second inclined portion 13 in a direction forming an angle theta satisfying expression (1) with respect to the normal-line direction R, and light source 21 which irradiates either of the inclined portions from a direction forming an angle alpha satisfying expression (2) with respect to the normal-line direction R: 30°@theta@35°(1) Deltatheta=theta-180°+alpha+2beta(2) where beta is less than 90°, Deltatheta is not less than -10° but not more than 10°, and theta and alpha are angles in a turn direction reverse to a turn direction at which either of the inclined portions forms the angle beta with respect to the normal-line direction R.