FIELD: optical scanning systems. SUBSTANCE: scanning unit has radiation source, objective and system for detecting linear and angular position of objective along and about two mutual perpendicular axes. Detection system is mounted a the direction of radiation reflected from the mirror. Mirror is made in form of a cone and mounted coaxially with optical axis of objective. Moreover, the mirror is made in form of either bevelled edge of the objective or in form of bevelled edge of lens covered with reflecting layer. The mirror is provided also with axial position system. EFFECT: improved precision. 9 cl, 7 dwg
