Single-layer UniGlo® fiber optic panel from Poly-Optical® Products, Inc has improved backlighting of the control panel LCD used in a portable instrument for locating underground cables and pipes, while helping the manufacturer assemble the device more rapidly, at lower overall cost.
The RD4000Rx Receiver is a comprehensive pipe and cable locator device with fault finding capabilities that operates by sensing the electromagnetic field produced by underground cables and pipes. Manufactured by Radiodetection Ltd, Bristol, UK, it is widely used by utility companies and contractors to locate underground services from the surface, prior to excavation.
The control panel, which provides information such as signal strength, depth of cover, operating mode, and battery status, is a backlit LCD. Previously, the company backlit the display with a prismatic edge-lit rectangular diffuser with 12 red LEDs. However, Radiodetection wanted the backlight to provide more even illumination of the LCD without "hot spots," reduce power consumption, and improve the reliability of the display.
The solution was a single-layer UniGlo® fiber optic panel from Poly-Optical® Products, Irvine, CA. These exceptionally thin (0.013 in./0.33mm) panels provide a rugged, durable, and uniform area of light that is completely free of heat and EMI.
"This eliminated the possibility of the high sensitivity electromagnetic sensors in the RD4000Rx from being compromised by the localized EMI emissions from other backlighting technologies we considered, such as EL and CCFL," said Richard Pearson, senior engineer at Radiodetection.
Using the UniGlo® panel, the RD4000Rx could be backlit by a single, low-power LED with a forward drop at 3.6V at 20 mA. "The optical fiber panel provides the evenness of illumination we were aiming for and is extremely power efficient," said Pearson. "It contributes to improvements in the overall quality of our product."
The UniGlo® panel is also rugged, easily meeting Radiodetection's requirements of 40G maximum shock or peak vibration and MTBF in excess of 15,000 hours. It provides a wide operating temperature range of -40ºC to +80ºC.
The panel's easy installation means it is easily replaceable in the unlikely event of failure. "The panel had to be modified to meet the requirements of the subcontractor in China who manufactures our LCDs," said Pearson. "Poly-Optical was very helpful in working directly with them to resolve the LCD assembly issues."
The UniGlo® panel also successfully met Radiodetection's cost requirements. "It had the lowest cost while satisfying all of our performance requirements," said Pearson.
