Good scribing is key to high cell efficiency. Scribe widths, pitches, and offsets must be accurately controlled to produce panels with maximum conversion efficiencies, and the coatings must be precisely removed.
Traditional metrology and inspection methods use matrix cameras which sample less than 0.05% of the scribe and do so at a very slow rate. While providing information about scribe width and offset, they do nothing to ensure panel quality; broken scribes, overlapping scribes, missing scribes, defects, and coating residuals can exist anywhere, reducing panel efficiency. Also, matrix cameras are subject to panel warp and bounce, causing the imaging to go out of focus. While autofocusing systems are available, they cannot keep up with production line speed, requiring the panel to be slowed dramatically in order for the systems to work. For all of these reasons, matrix cameras are not the correct solution for dealing with the ever-increasing challenge of improving panel efficiency on a photovoltaic (PV) production line.
A new metrology technology using darkfield optics and high-speed scan cameras has been proven on production lines for on-line P1, P2, and P3 scribing operations. NxtGen Scribe 100 systems deliver what the current matrix camera systems cannot—100% scribe metrology, for all scribes, on-line, in real-time.
• Scribe widths and standard deviations—first third, middle third, last third and panel composite
• Scribe offsets
• Scribe pitch
• Measurement resolution ±2–5 µm
• % of scribe missing—data for each scribe
• Spacing violations—scribes too close or overlapping or too far apart at any point
• Measurement of the amount of residual coating left in the scribes--violation of control limits
• Scribe defect detection
• Optics remain in focus for warped and bouncing panels or webs at speeds to 30 m/min
This new, proven technology is critical for maximizing conversion efficiencies, controlling scribing operations, and providing early warning for maintenance of the scribe heads.
Dark Field Technologies (Orange, CT, USA) has led the inspection industry for more than 14 years with innovative and first-of-a-kind laser and camera-based inspection and metrology systems. From retroreflective laser systems for the float glass industry to high-resolution telecentric laser and camera systems for coated glass, display films, display glass, electronics, and semiconductor applications, Dark Field Technologies has been the technology vanguard.
-- Posted by Vision Systems Design
NxtGen Scribe 100 from Dark Field provides on-line, real-time 100% scribe metrology
A new metrology technology using darkfield optics and high-speed scan cameras has been proven on production lines for on-line P1, P2, and P3 scribing operations.