New Sources to Replace UHP Lamps in Rear Projection TVs

Approaches vary from Luminus LEDs deployed in Samsung’s DLP-based TVs to Luxim LiFi technology in Panasonic LCD rear projection sets. The LiFi technology dispenses with metal electrodes used in conventional lamps to discharge electricity into a gas in favor of RF energy injected into a sealed gas capsule emitter. Along with these a Novalux laser-based approach is expected to find a home in TVs by next spring.

“Microdisplay TV is now at a tipping point,” with LEDs and other forms of illumination bound to be replacing UHP lamps in rear projection sets by late 2008, said Christian Hoepfner, vice president of products at Luminus Devices, which this year is supplying LEDs for six Samsung TVs. “It’s becoming difficult” for LEDs and UHP lamps to co-exist in a product line as cost differences narrow and new technologies promise longer lifetimes and more efficiency, he said. Luminus claims a lifetime of 126,000 hours for its LEDs.

The retail price delta between LED-based sets and those with conventional lamps is expected to drop to $100 to $200 by year-end, from about $300 today, Hoepfner said. The Samsung sets deliver about 500 lumens using Luminus PT120 LEDs built in three-chip packages about 14 millimeters square.

Luxim, whose lamp is in Panasonic 50, 56 and 61-inch LCD-based rear projection TVs with 1080p resolution, is moving quickly to boost bulb brightness. Luxim unveiled the LiFi 4000+ bulb here; it’s designed to deliver 5,500 peak lumens, up from 4,000 in the LiFi 4000 built into the Panasonic TVs. The sets, once optics and other components that reduce light output are factored in, deliver about 400 lumens and have a 3,000:1 contrast ratio. Luxim expects to start production of the 4000+ third quarter. Much increased brightness will be accomplished by narrowing the bulb’s arc gap to about 1.5 millimeters from the current 2.5 millimeters, CEO Tony McGettigan said. The 4,000+ will maintain 80 percent brightness after 25,000 hours of use and has a 10-second start time. At the heart of the Luxim technology are RF transmitters and receivers combined with a 170-watt amplifier connected to the bulb. The amplifier focuses the electric field response and creates a standing wavelength. Luxim is assembling the bulbs at its Sunnyvale, Cal., facility, hoping to boost capacity by the third quarter to 15,000 units per month from 7,500. OEM partner World Fair assembles Luxim circuit boards and lamps in China, said Sales and Marketing Vice President Julian Carey. Luxim next plans to target front projectors delivering 600 to 800 lumens, company officials said.

Despite advances in LEDs and bulbs, laser fans say that technology will emerge as the dominant light source for rear projection TVs by 2010. Novalux plans to start production of its lasers for TVs by the fourth quarter, aiming to have one to two customers fielding products the first half of 2008, said Gregory Niven, Novalux executive vice president of marketing. Many of those sets will be based on three-watt lasers. While Novalux hasn’t identified its customers, Mitsubishi has been said to be among them. Mitsubishi expects to ship a limited number of laser-based sets by year- end. Companies throwing their support behind laser include LCoS developer Syndiant, now developing a 0.4 to 0.5-inch chip with 1080p resolution that’s expected to start sampling in the fourth quarter, said Chief Technology Officer Karl Guttag. The microdisplay likely will be built using a 0.18- micron process by United Microelectronics, he said. “If you don’t have a laser, I don’t think you have a microdisplay market longer term,” Guttag said.

Lasers have an edge over LEDs and lamps in producing saturated primary colors more than 90% of what an eye can see vs. 40 to 45 percent (lamps) and 55 to 60 percent (LEDs) -- Niven said. But lasers also have issues with speckle - grainy patterns seen when a laser is reflected diffusely at a display screen and inherent to the technology, industry officials said. Cost likely will be a barrier, officials said. “Is it (laser) really here or is it a high cost area with niche applications,” said James Shanley, chief technology officer at Scram Technologies. “The jury is still out on that.”

Along with Novalux, optical components developer Oerlikon threw its support behind laser. It announced an alliance with Microvision to develop optics for the latter’s PicoP projector MEMS-based technology, designed to be embedded in a cellphone. Oerlikon, which will design and assemble the laser modules, demonstrated the technology at the conference here using 40- to 50-milliwatt lasers producing 20 lumens. The red, blue and green lasers operated at 615 to 620, 465 and 532.5 nanometers, company officials said. Prototype lasers designed for PicoP draw three to five watts, but the goal is to hit one-and-a-half watts when product is released in 2008, company officials said. Oerlikon, which is working with Novalux, shipped first samples of its three-watt laser module and plans to add a 100-milliwatt version by mid-year, Business Development Manager Ed Passon said. “Lasers are the end game for light sources” that can help microdisplay-based rear projection TVs remain competitive with flat-panel displays, Passon said.

Projection Summit Notes…

Later this year Amimon expects to form a consortium to help set preliminary standards for wireless transmission of high definition (WHDI) technology by mid-2008, said Product Management Director Netanel Goldberg. WHDI, which is targeting transmission of HD 1080p video in the 5 GHz band, numbers among its allies Sanyo and Motorola, the latter having invested in Amimon earlier this year through a venture capital arm. Sanyo is expected to ship an WHDI-equipped large venue front projector priced at around $10,000 later this year, with other partners to release accessories and flat-screen TVs in 2008, Goldberg said. Amimon’s WHDI technology is designed to break video streams into levels of visual significance then mapped onto the wireless channel, Co-Founder Noam Geri said. “This is done in a way that the more important visual information gets more protection from noise than less important data.” Using this approach, Amimon has demonstrated delivery of uncompressed 720p and 1080i - about 1.5 Gbps of video - at up to 100 feet using a 20 MHz channel and multi-input-multi-output (MIMO) OFDM modem in the 5 GHz band, company officials said. Uncompressed 1080p video can be sent a similar distance using a 40 MHz channel in the 5 GHz band at rates up to 3 Gbps. Amimon hopes to start sampling the four-chip set - two baseband processors, two RF receiver chips - in July, with a goal of volume production fourth quarter, Goldberg said. The processors operate at 100/200 MHz clock speeds and the chipset uses five 802.11a transceivers to get the signal to the RF ICs, he said. Taiwan Semiconductor Manufacturing Corp. (TSMC) is making the chipset using a 0.13-micron process, Goldberg said. The sample circuit board contains 6 receiver and 5 transceiver antennas, company officials said. In addition to the projector, a dongle box containing the WHDI technology will be available by Jan., Goldberg said. WHDI is aimed squarely at rivaling WirelessHD, which uses the so-called 60 GHz “millimeter band” to deliver HD signals and advanced audio throughout homes. Toshiba said earlier this month (CED June 18 p1) that low-cost CMOS is the way to get high-speed wireless communication within homes using the 60 GHz band. WirelessHD has the backing of Toshiba as well as LG Electronics, NEC Panasonic Sony and start-up SiBeam. Unlike WHDI, WirelessHD uses video compression technology “very sensitive” to bit-rate errors, Geri said. It also suffers from “significant degradation” of video quality and “high latency” that the compression encoders create, he said.

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Luminus is packaging its LEDs with a two-year warranty for manufacturers as it seeks to expand use of the technology in CE products, company officials said. “We have sufficient testing to support the idea that the light source can be comfortably included by a manufacturer just like any other solid state component used in the TV like a Genesis video processor or a semiconductor part,” said Paul Fredrickson, director of marketing at Luminus. Two years is a “sufficiently long period of time” for a typical parts and labor warranty without making an exception for the light source, as sometimes is done with conventional lamps, Fredrickson said. Under the warranty, Luminus will cover the replacement cost, he said. Samsung has deployed the LEDs in six DLP-based rear projection TVs, while LG Electronics is using to PT39 chipset in a pocket projector that ships this month in South Korea. The LG projector uses a single 0.55- inch DLP chip with 800x600 resolution and contains 100 lumens. The four-millimeter square PT39 chipset produces about 1,000 peak lumens, but the 10 to 15 percent efficiency of the projector lowers the brightness to 100 lumens. - Mark Seavy