Panasonic announced on Sunday that all its RPTV sets in the future will use the Luxim LiFi lamp instead of UHP-type, xenon lamps, lasers or LEDs. LiFi stands for Light Fidelity, a reference to the improved spectrum and color of the lamp, compared to a UHP type spectrum. In the Panasonic booth at CES this week, there is not only a LiFi-powered RPTV but there is an operating lamp on display.

Matt Brennesholtz
Insight Media Analyst

Panasonic touts three advantages this lamp has over conventional HID lamps:

• Improved color, especially red color, compared to UHP-type lamps.
• Shorter warm-up times, about 3 to 10 seconds compared to the approximate 1 minute for UHP-type lamps.
• Longer lifetime, 20,000 hours or more, compared to the 4,000 hours of a UHP-type lamp with comparable light output.

Insight Media will vouch for the improved colorimetry. In the demonstration projectors the reds were clearly superior to the reds we have come expect out of an RPTV.

According to the Panasonic announcement, the short warm up time is due to the small size of the bulb, about 1/8 the size of the bulb on a conventional HID lamp. This small size bulb then heats up quickly, vaporizing the fill material. In the Panasonic booth was a sample LiFi source cycling on and off every thirty seconds or so. This allowed CES attendees to see for themselves how fast the warm up is. After it is turned off, the lamp must be off for at least 20 seconds before it can be restarted.

This lamp, unlike conventional HID lamps, has no electrodes. Instead the plasma is driven with microwave power in a resonant cavity. Since the electrodes are often a major factor in the failure of a HID lamp, eliminating the electrodes eliminates several major failure mechanisms of HID lamps. This allows the long life, and makes it possible to design systems that never need lamp replacement. According to Luxim, this 20,000 hours is not a hard limit, but is limited more by the testing data than by the lamp. As additional data is accumulated, the specified lamp life may be extended.

The lamp has a couple of disadvantages, however. First, it is physically bigger than the UHP-type lamp it replaces. This is not seen as a problem in RPTV sets, but it might be an issue in front projectors. Second, it is less power efficient. The LiFi lamp plus microwave driver in the Panasonic set consumes about 250W. It replaces a 180W lamp used in previous Panasonic 3LCD RPTV sets. The 180W lamp also dissipated about 30W in the ballast, for a total of 210W vs 250W for LiFi. Finally, while neither Luxim nor Panasonic would talk about the price of the lamp, Insight Media believes it is currently more expensive than the mature UHP-type it replaces. Since Panasonic is committed to using the lamp in all its RPTV sets, apparently they feel the advantages outweigh the disadvantages.

More details on this system and other large screen systems at CES will be in the February Projection Monthly with Flat Panel Coverage. Coverage of smaller displays at CES will be in the January and February issues of Mobile Display Report.