Patent ID: 7992958

Claim:
A method for forming a printed pattern from a pattern layout using a printing system, the printing system comprising a print head and a camera rigidly connected to the print head, the camera having an imaging sensor, the method comprising: performing a first alignment operation to achieve a specified orientation between the print head and a first set of alignment marks on a substrate using first image data generated by the imaging sensor of the camera; performing a first print operation after the first alignment operation to print a first portion of the pattern layout on the substrate to generate a first portion of the printed pattern, wherein performing the first print operation includes making a plurality of printing passes across the substrate in a first print direction; performing a second alignment operation to orient the print head relative to a second set of alignment marks on the substrate using second image data generated by the imaging sensor of the camera; and performing a second print operation to print a second portion of the pattern layout on the substrate to generate a second portion of the printed pattern, wherein performing the second print operation includes making a plurality of printing passes across the substrate in a second print direction that is non-parallel to the first print direction, wherein the print head comprises a first ejector and a second ejector, and wherein performing the first alignment operation comprises: positioning the first ejector at a first location over the substrate and printing a first spot on the substrate; positioning the second ejector at the first location and printing a second spot on the substrate; measuring a distance between the first spot and the second spot; adjusting a rotational orientation between the print head and the substrate to reduce the distance between the first spot and the second spot; and repeating the steps of positioning the first ejector, positioning the second ejector, measuring the distance, and adjusting the rotational orientation until the distance between the first spot and the second spot is less than a predefined threshold value.