OPTISK GIVARE FOER AVKAENNING AV ETT SKRIVHUVUDS LAEGE ELLER ROERELSE RELATIVT EN REFERENS

摘要

The invention relates to an optical transducer for position or motion. The transducer comprises a light source (10), two optical measuring screens (21 and 22) and a light receiver. The measuring screens are arranged to enter different positions relative to one another in the beam path between light source and light receiver. Each measuring screen has first portions forwarding light from the light source to the light receiver and second portions not forwarding light from the light source to the light receiver. The measuring screens have different pitches and the width of the second portions of each measuring screen is substantially larger than the width of the first portions of the second measuring screen. When the measuring screens are in a first position relative to one another the light receiver can receive light from the light source via at least two first portions in each measuring screen at the same time. When the measuring screens are in a second position relative to one another the second portions shield the light receiver completely from the light of the light source.