Feedback circuit for calibrating a current mode display

A method for collecting feedback on a display, the method comprising:

• driving a plurality of emitters arranged in a column, wherein each emitter of the plurality of emitters is driven by a respective emitter cell that generates a driving current for the emitter based on digital data or an analog representation of the digital data;
• shifting the digital data or analog representation through the emitter cells such that the entire column of emitters is driven based on the digital data or analog representation;
• after shifting the digital data or analog representation through the emitter cells, measuring an electrical signal corresponding to a bias current developed at a last emitter of the plurality of emitters to be driven based on the digital data or analog representation, wherein the electrical signal is measured along a feedback path leading from the last emitter, and wherein due to the emitter cells being connected in a chain, each emitter cell contributes to the bias current such that the bias current is indicative of a collective performance of all the emitter cells;
• comparing a value of the electrical signal to an expected value;
• and
• adjusting, based on the comparing, an extent to which each of the emitters is subsequently driven.

A computer readable storage medium storing instructions that, when executed by one or more processors of a computer system including a display, cause the one or more processors to:

• drive a plurality of emitters arranged in a column, wherein each emitter of the plurality of emitters is driven by a respective emitter cell that generates a driving current for the emitter based on digital data or an analog representation of the digital data;
• shift the digital data or analog representation through the emitter cells such that the entire column of emitters is driven based on the digital data or analog representation;
• after shifting the digital data or analog representation through the emitter cells, measure an electrical signal corresponding to a bias current developed at a last emitter of the plurality of emitters to be driven based on the digital data or analog representation, wherein the electrical signal is measured along a feedback path leading from the last emitter, and wherein due to the emitter cells being connected in a chain, each emitter cell contributes to the bias current such that the bias current is indicative of a collective performance of all the emitter cells;
• compare a value of the electrical signal to an expected value;
• adjust, based on the comparing, an extent to which each of the emitters is subsequently driven;
• and
• rotate a reflective surface of a scanning assembly to form an output image by reflecting light emitted from the plurality of emitters, wherein the reflective surface is rotated through a plurality of positions such that at different rotational positions, light emitted from different emitters of the plurality of emitters is reflected onto a same pixel of the output image such that a brightness of the pixel corresponds to an aggregate brightness of the different emitters.