| 摘要 |
<p>An improved photoelectric incremental measuring apparatus for measuring the relative displacement of two objects is disclosed, the apparatus including a measuring scale and a scanning unit for scanning the scale having a reticle, the scale and reticle each carrying a measuring grid. The scale has at least two nonidentical reference marks, each of which comprises a line group with an irregular line spacing pattern. The reticle has at least two reading fields, each of which comprises a line group with an irregular line spacing pattern that is identical to the line spacing pattern of a selected one of the reference marks. The reading fields occupy such positions on the reticle that each reading field aligns with its corresponding reference mark simultaneously as the scanning unit moves along the scale. Each reading position on the scanning unit is illuminated by a light source, such as a lamp, and the light sources are connected across a common resistor, mounted in series, to a power source.</p> |
