Optical position encoder having alignment indicators providing quantitative alignment indications

A method of providing information to a user regarding alignment of an optical detector and an encoder scale in an alignment direction of an optical encoder, the alignment direction being orthogonal to a direction of relative motion between the optical detector and the encoder scale, the method comprising:

• obtaining optical detector output signals indicative of the location of an optical pattern on the optical detector in the alignment direction, the optical pattern being generated by the encoder scale in conjunction with a light beam from an optical source;
• continually generating alignment values in response to the detector output signals, each alignment value indicating a polarity and a magnitude of misalignment in the alignment direction between the optical detector and the encoder scale;
• and
• displaying a graphical alignment indicator having an indicator scale and a marker, the indicator scale being a bipolar indicator scale capable of indicating both polarity and magnitude of misalignment, the location of the marker being based on the alignment values such that the magnitude and polarity of misalignment in the alignment direction between the optical detector and the indicator scale are indicated by the graphical alignment indicator.

A computer program product that includes a computer readable medium having instructions stored thereon for providing information to a user regarding alignment of an optical detector and an encoder scale in an alignment direction of an optical encoder, the alignment direction being orthogonal to a direction of relative motion between the optical detector and the encoder scale, such that the instructions, when carried out by a computerized system, cause the computerized system to:

• obtain optical detector output signals indicative of the location of an optical pattern on the optical detector in the alignment direction, the optical pattern being generated by the encoder scale in conjunction with a light beam from an optical source;
• continually generate alignment values in response to the detector output signals, each alignment value indicating a polarity and a magnitude of misalignment in the alignment direction between the optical detector and the encoder scale;
• and
• display a graphical alignment indicator having an indicator scale and a marker, the indicator scale being a bipolar indicator scale capable of indicating both polarity and magnitude of misalignment, the location of the marker being based on the alignment values such that the magnitude and polarity of misalignment in the alignment direction between the optical detector and the indicator scale are indicated by the graphical alignment indicator.