Patent ID: 7057161

Claim:
A position measuring device comprising: a scanning device; and a scale, wherein said scanning device is movable in relation to said scale in a measuring direction, said scale comprising: a measuring graduation, wherein periodic measuring signals are generated when said scanning device scans said measuring graduation; a reference marking, wherein a reference marking signal is generated when said scanning device scans said reference marking with a scanning beam bundle; a first optically scannable area marking next to said reference marking and a second optically scannable area marking next to said reference marking and which has a different optical deflection property than said first optically scannable area marking, wherein photoelectric scanning of said first and second optically scannable area markings with said scanning beam bundle from said scanning device generates an area signal that differentiates characteristics of said first and second optically scannable area markings; a first photo-receiver receives light from said first optically scannable area marking; and a second photo-receiver receives light from said second optically scannable area marking.