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December 21 2005

NTN Develops "Rib Repair System For Plasma Displays"

NTN Corporation has developed a rib-repair system targeting the flat-panel display (FPD) repair market. Using 3Dmicro-deposition technology, this system is able to rapidly fill in defects in the ribs (thin walls about 0.1 -0.2 mm high to 0.05-0.06 mm wide) in the back panels of plasma displays, with a uniform width.


As flat-panel displays grow larger and have greater resolution, there is a demand for technologies to repair some types of defects occurring in glass panels, to make them usable. The industry is requiring these systems to perform repairs more rapidly and improve the quality of the repairs.


Conventional plasma-display repair devices fill in ribs with repair fluid. It is then baked, solidifying the fluid and completing the repair. Although it is relatively easy to repair small rib defects using this technique repairing complex, larger rib defects requires multiple coatings of repair fluid, costing large amounts of time.


The system developed by NTN features the ability to rapidly form a three-dimensional micro-pattern by funneling atomized repair fluid using sheath gas (compressed gas), and spraying it onto a heated rib defect. As a result, the system can easily repair larger rib defects of several hundred microns, which were difficult for conventional repair systems. Additionally, the deposition is nearly the same width as the ribs, improving repair quality by preventing ribs from side drop after the repair.


[Rib Repair Features]

  1. Can Form Deposition Patterns
    The system is capable of forming 3D deposit layers, by spraying atomized repair fluid in layers over the defect through a nozzle. This method makes it easy to repair deep and long defects.
  2. Capable of High Quality Repairs
    The addition of baking and tape-polishing features to the system enables the repair to have the same width and height as the rib.

[Target Market]

  • Rib defects in plasma displays

[Features]

  1. Quickly fills in defects in the ribs on the back panels of plasma displays
    • Capable of forming deposition (membranes) with nearly same width as the ribs
    • Capable of forming deposition on any irregular gap of ribs
    • Forms deposition without contact
  2. After filling and baking, protuberances are eliminated through tape polishing
    • Enables repairs to have same height as normal ribs

Defective ribs cause these defects:

  1. Causes neighboring colors to mix during manufacture
  2. Lights shine to the next color, or fail to light.

[Engineering breakthroughs]

Atomizes and deposits repair material with 3D micro-deposition system
→Result: Deposits are formed by stacking deposition layer

Terminology
Atomizer Atomizes (turns into mist) repair material (paste)
Virtual impactor Expels carrier gas used for atomization
Heater Heats the mist
Nozzle Funneled opening through which mist is sprayed via sheath gas
Laser Heats substrate (gasifies solvent medium in the mist)
Shutter Turns spraying on and off

How it Works
A few microns of mist (liquid droplets) formed by an atomizer are sprayed via sheath gas onto a heated substrate, drying at the same time as they adhere.
→Result: A deposit line is formed.

Features
  • Can form lines a few 10s of microns across
  • Can form deposition patterns



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