A BETTER MOUSETRAP?
Nov 1, 2000 12:00 PM,
Peter H. Putman
JVC’s D-ILA challenges Texas Intruments’ DLPIt is remarkable how quickly the face of the electronic display industry changes. Just five years ago, the first commercially available single-chip Digital Light Processing (DLP) projector was introduced at INFOCOMM in Dallas. At more than 20 pounds (9 kg), this 848×600 resolution unit represented the start of a major shakeup in display technology that has affected every category from small portable projectors to high-brightness, large venue projectors.
Since that time, DLP has become a dominant imaging process. It has matured and outlasted the company that introduced that first DMD-equipped projector (nView), forced one manufacturer of large venue projectors to move away from transmissive LCD panels and get with the program (Barco) and led another to retire its complex CRT/LCD hybrid projectors (Hughes-JVC).
Thanks to a well-coordinated media blitz and marketing campaign, the term DLP has become an industry buzzword, even if many who use it understand little about how DLP actually works. The coinciding development of electronic cinema propelled DLP technology even further with screenings of numerous feature films on DLP Cinema projectors. Today, DLP projectors have been used extensively in film festivals, rear-projection devices for TV dynamic set pieces and a wide range of configurations and staging jobs.
Three companies – Christie Digital (formerly Electrohome), Digital Projection and Barco – have signed exclusive agreements with Texas Instruments to develop cinema-grade projectors based on TI’s 1.3 inch (33 mm) 1,280×1,024 dark chip DMDs. A variant of that chip, masking to 1,280×720 pixels, has been picked up by three more manufacturers (Mitsubishi, Hitachi and Panasonic) for use in rear-projection TV sets.
Sony, Panasonic and NEC are also manufacturing three-chip large-venue DLP projectors in a variety of sizes, resolutions and brightness levels. Among the desktop crowd, In Focus, Proxima, Plus, Sharp, Mitsubishi, Panasonic, Davis and NEC are all cranking out ultraportable and desktop single-chip DLP light boxes, while Dwin, Runco, Seleco, Vidikron and Marantz are targeting the home-theater and high-end consumer channels. TI’s avalanche of reflective imaging devices may appear to be unstoppable, but there is yet another player looming on the horizon.
JVC, the parent company of the now-defunct Hughes-JVC division, has decided to ramp up production of its Digital Image Light Amplifier (D-ILA), a reflective LCD imaging technology that is also described as Liquid Crystal On Silicon (LCOS). The D-ILA is a small (0.9 inch or 23 mm diagonal) SXGA (1,365×1,024 pixel) imaging device that shows great promise and is scalable to higher resolutions. At this year’s INFOCOMM, JVC announced that second-generation 1.3 inch D-ILA panels with a native resolution of 2,048×1,536 pixels will be available in 2001. This resolution, also known as Quad XGA or QXGA, will allow 1080i HDTV images to be shown at full resolution without the need for scaling or cropping, which is a trick that TI cannot pull off presently, and its own timetable for introduction of QXGA DMDs is unknown.
JVC, however, did not stop there, showing prototypes of a 1.3 inch QUXGA panel, which has a horizontal resolution much more than 2,500 pixels. Adding to the fun, JVC also announced a smaller version of its SXGA panel, shrinking it down to 0.7 inches (18 mm) diagonally. A 0.5 inch (13 mm) XGA (1,024×768) version is also expected in 2001, as is a 0.5 inch 1,280×720 pixel (16:9) panel. There is more; a 0.9 inch 1,920×1,080 (16:9) panel is on the calendar for 2002.
Pretty ambitious plans, but you can bet that TI is taking these announcements seriously because their smallest, currently available devices (also 0.7 inches diagonal) are capable of only 1,024×768 resolution. Smaller imaging panels are of paramount importance because they will make it possible to design compact, high-brightness, high-resolution installation projectors using xenon-based RGB color imaging. That’s a market every projector manufacturer is drooling after.
JVC topped off its announcements with a full demonstration of the DLA-G3010Z, a three-panel, 1,365×1,024 resolution desktop/installation projector that weighs slightly more than 14 pounds (6.3 kg) and is claimed to deliver 1,300 ANSI lumens. Right now, there is no such product available to the professional A-V or staging and rental channels, so the DLA-G3010Z (if and when it starts shipping) is a perfect fit for the compact boardroom/conference room installation market.
Overcoming obstaclesAlthough JVC’s plans for the D-ILA are ambitious, it has a couple of hurdles to jump to be competitive with DLP. To start, the current optical path in D-ILA projectors is not too efficient, requiring lamps with 1.5 to 2 times the power level of comparably equipped DLP projectors. As an example, the MLA-4000U high-brightness D-ILA chassis needs a 1.6 kW xenon lamp to deliver its claimed 4,000 lumens, while a comparable, typical DLP product (Christie Digital’s Roadster S4) comes close to that ANSI specification using a lamp rated at half the wattage (700 W xenon). Additionally, the Roadster S4 is considerably lighter, tipping the scales at only 92 pounds (41 kg) as opposed to the MLA-4000U’s much heavier 157 pounds (71 kg).
Another issue has been video signal quality. Most demos of JVC projectors have looked best with either 1080i HDTV or an external high-quality video decoder and scalar doing the de-interlacing and color separation of NTSC sources. To compete in the large-venue arena, JVC will need to spend additional time, money and research improving video decoding and image scaling.
On the other hand, DLP projector design is at least a year or two ahead of the D-ILA, and there is no reason to expect that JVC will not be able to get over these hurdles. Plus, it has an ace up its sleeve, and that is to make D-ILA chips available to any projector manufacturer who wants to use them.
There is precedent for this move. Epson, a major LCD projector manufacturer, has done well selling transmissive LCD panels and complete LCD optical engines to numerous OEM partners. Sony has done the same on a more limited basis with both Sharp and Sanyo. This process helps accelerate engineering cost recovery and return on investment for each new D-ILA device that JVC brings to market. Having several OEM partners also means that many more brains are available to work on such issues as brightness, weight, size and image quality.
Of course, the DMD remains the only purely digital flat-matrix imaging device available and will probably keep that crown for some time. Both transmissive and reflective liquid crystal panels can be addressed digitally, but the individual LC pixels have an analog response. The advantage of reflective over transmissive liquid crystal is its efficiency – more light arrives at the lens. The switching transistors are part of the LCD panel’s backplane and are not formed on an imaging surface, so their thickness and transparency is not as much of an issue.
This is part of the reason that the D-ILA can be reduced in size while increasing in resolution. There are no restrictions on image brightness either. As long as infrared light (heat) from the lamp is controlled, it is entirely feasible to build a 10,000 lumens D-ILA chassis. The development of a small polarized beam splitter (PBS) will help reduce the size of the optical path.
The tricky part will be improving contrast. Reflective imaging devices usually have a hard time with black levels, partly because of scattered light around the surface and structure of the DMD or LCD panel. Even though the light is polarized, which is necessary to achieve a shuttering effect and vary brightness levels, some light will always misbehave and go outside the optical path.
TI reduced this problem somewhat in its DMDs by coating all surfaces inside the DMD (except the actual mirrors) with a light-absorbing substance (hence the name “dark chip”). Such a trick may also be necessary for the D-ILA because most of the models that I have tested to date have fairly high black levels (10% to 15% gray). Dropping black levels is an absolute necessity if JVC hopes to get the D-ILA into any cinema applications.
What does this reflective technology tussle mean to you, the systems integrator? It is good news, particularly if you have clients looking for higher resolution in a flat-matrix projection system. It is a sure bet that TI will not have QXGA DMDs available for at least a year. Assuming JVC can finesse the image quality and efficiency issues, the D-ILA could turn out to be a worthy match for the DMD.
