High Resolution Single Track Optical Encoder

A method of making a high resolution single track reflective optical encoder, comprising:

• providing a light emitter configured to emit light therefrom;
• providing a plurality of photodetectors or photodiodes having leading and trailing edges arranged along a single track and a common axis to form a single track light detector, the single track light detector having disposed along the common axis a plurality of pairs of A and A\ data channel light detectors, and B and B\ data channel light detectors, the A and B light detectors, and the A\ and B\ light detectors, respectively, being arranged to generate output signals that are 90 degrees out of phase with respect to one another;
• providing a code scale comprising alternating optically substantially reflective and substantially non-reflective data strips, wherein any pair of adjoining reflective and non-reflective data strips disposed on the code scale has a combined width equal to X, the code scale being configured to travel along the common axis and being located and configured operably in respect of the single track light detector such that at least a portion of the light emitted from the light emitter is reflected from the code scale towards the data channel light detectors, and
• arranging a spacing between at least some adjoining photodetectors or photodiodes disposed along the single track and the common axis such that the spacing is greater than or equal to X/2, the spacing being measured between either the leading edges or the trailing edges of such adjoining photodetectors or photodiodes, the spacing being sufficiently large to prevent or inhibit cross-talk between adjoining photodiodes, the resulting optical encoder having a spatial resolution of X/2.

A method of encoding light signals generated by an optical encoder having a single track and a common axis, comprising:

• emitting light from a light emitter towards a code scale;
• reflecting at least a portion of the light emitted by the light emitter from the code scale, the code scale comprising alternating optically substantially reflective and substantially non-reflective data strips, wherein any pair of adjoining reflective and non-reflective data strips disposed on the code scale has a combined width equal to X, the code scale being configured to travel along the common axis;
• detecting at least a portion of the light reflected from the code scale with a plurality of photodetectors or photodiodes having leading and trailing edges arranged along the single track and the common axis to form a single track light detector, the single track light detector having disposed along the common axis a plurality of pairs of A and A\ data channel light detectors, and B and B\ data channel light detectors, the A and B light detectors, and the A\ and B\ light detectors, respectively, being arranged to generate output signals that are 90 degrees out of phase with respect to one another, and
• arranging a spacing between at least some adjoining photodetectors or photodiodes disposed along the single track and the common axis such that the spacing is greater than or equal to X/2, the spacing being measured between either the leading edges or the trailing edges of such adjoining photodetectors or photodiodes, the spacing being sufficiently large to prevent or inhibit cross-talk between adjoining photodiodes, the resulting optical encoder having a spatial resolution of X/2.