Method to control the printing of a pattern printed on a substrate

Abstract

The present invention provides a method and apparatus to control the printing of a pattern printed on a substrate, such as a wafer to form photovoltaic cells or circuits of the green-tape type. In one embodiment, a method to control the printing of a pattern printed on a substrate includes printing on a surface of the substrate a plurality of print tracks to define the pattern, by means of optical acquisition verifying the printing of the print tracks on the substrate. Verifying comprises acquiring a first reference optical image ( 301 ) of the surface of the substrate, or reference substrate, by means of an inspection unit, carried out before printing; processing the first image, in which a processing unit or controller determines reference geometric coordinates ( X1,Y1 , X2,Y2 , X3,Y3 , X4,Y4 ) of the first image and memorizes the geometric coordinates; subsequent to the printing, by means of the inspection unit, acquiring a second image ( 303 ) of the surface of the substrate on which the print tracks ( 302 ) are printed; processing the second image by means of the processing unit or controller that associates the geometric reference coordinates of the first image to the second image; the processing unit or controller subtracting point by point the colorings between the first image and the second image to obtain a third image ( 307 ), in which the differences between the first image and the second image are displayed.

Description

technical field [0001] Embodiments of the invention generally relate to a method and apparatus for controlling the printing by optical trapping of a pattern printed on a substrate or support useful for forming photovoltaic cells or green tape type circuits device. In particular, the method according to the invention can be used in systems for producing multilayer patterns by multilayer printing on a substrate, whether screen printing, inkjet printing, laser printing or other types of printing . Background technique [0002] Solar cells are photovoltaic (PV) devices that convert sunlight directly into electricity. Over the past decade, the PV market has experienced an annual growth rate of more than 30%. Some articles suggest that global solar cell electricity production could exceed 10GWp in the near future. It is estimated that more than 95% of all solar modules are based on silicon wafers. High market growth rates coupled with the need to drastically reduce the cost o...

AI Technical Summary

Problems solved by technology

In this case, however, it is difficult to identify possible printing defects, e.g. misalignment or possible spotting or printing defects relative to the deposited print on the cell surface

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