| 摘要 |
The invention concerns an arrangement for dimension measuring by means of a laser beam, which is directed from a light source 1 at a rotating mirror 3 and through a lens 4 situated at a focal length distance from the centre of rotation of the mirror at a measurement object 5 and is reflected onto said mirror to a light detector 8. Furthermore, a pulse transmitter 9 rotating together with the mirror 3 is arranged to control a computer 14 together with the light detector 8, which determines the sought dimension and feeds the result to a presentation unit 15. According to the invention, the new arrangement contains a diffusely reflecting surface arranged behind the measurement object 5, onto which the laser beam impinges essentially perpendicular and which is arranged to reflect somewhat diffused light onto said rotating mirror 3 and via a collecting lens 7 onto the detector 8, and the pulse transmitter 9 controls, as a function of the rotational speed of the mirror 3, a phase-locked oscillator 11, whose output is connected to one input of an AND-gate 12, which has a second input fed from said detector and in turn it feeds a pulse counter 13, connected to the input of the computer 14 in order to synchronise the rotational speed of the mirror 3 with the oscillator 11. <IMAGE> |
