Rainbow brings a new dimension to displays
23 April 2012
Rainbow Technology has developed a revolutionary new method for manufacturing touch-screen displays that it claims is more cost-effective, faster and greener than traditional methods.
The Rainbow Process Unit has been developed for PCB production but the technology can be equally applied to touchscreen displays as the technology is capable of producing very fine line circuitry (down to five microns). The unit incorporates coating, imaging and developing of PCBs in one compact, automated unit.
Central to the success of the Rainbow Process is the proprietary etch wet resist which does not require pre-drying (using a hot air or infra-red oven) before imaging. The resist is 100% solids and solvent free. Using only UV LEDs and standard photo-tools tracks and gaps of 20 microns and below are easily achieved. The unit has very low running costs with power consumption averaging 3kW.
Grid patterns of five micron by 300 micron pitch offer more conductivity than ITO or conductive polymers whilst still offering extremely good transparency. The process can be done additively using an imaged seed layer to create electroless plated nickel or copper with a Rainbow imaged plating resist to create tracks.
Alternatively the process can be done subtractively using sputtered metal on plastic using a Rainbow imaged etch resist to create tracks.
Key benefits of using the Rainbow process to produce the display is that the touchscreen will be more responsive due to the closer tracks and gaps (down to 10 micron spacing) allowing designers to introduce more features to the screen.