No longer playing second fiddle to 3-chip models, advancements in 1-chip projection technology are opening up new opportunities. Paul Milligan speaks to those on the inside.
pic caption: 50 1-chip laser projectors were used for ‘Ballad of Chu’, an immersive theatrical performance in China
It’s not been the best 10-15 years for projection. First of all, its place at the top table of AV was taken after a long battle with large format displays and was then further displaced by the unstoppable rise of LED videowalls. You’d be forgiven for thinking this product segment had been stagnant in that time, but there have been some recent innovations and one of those developments is bringing smaller projectors into new applications.
Since the shift to LFD/LED took place, the projection market has primarily concerned itself with large scale projects, such as cinema or projection mapping, which require heavyweight products, this meant manufacturers’ stands at trade shows were dominated by 30 or 40,000 lumens 3-chip models, all weighing closer to 100kg than 10kg. What has happened in the last few years has been a rise in innovation in 1-chip models, driven by a combination of buyer demands for smaller, lighter, more efficient, more powerful projectors and innovation from chip supplier Texas Instruments. There has always been a gap between 1-chip projectors and 3-chip projectors in terms of price and quality, it’s a case of you get what you pay for. Each one had its own distinct uses to a degree, but that is starting to change, and the gap in quality is closing too.
We asked a selection of projector manufacturers if they felt the rise in quality and new capabilities of the next generation of 1-chip projectors was causing buyers to re-assess their next projector purchase. Is the gap in quality between 1-chip and 3-chip projectors closing? “The short answer is yes; the main advantage of 3-chip models was the high colour brightness and the absence of a rainbow effect. But a well-designed 1-chip projector can now also achieve very high colour brightness levels. You can’t really say that 1-chip projector technology is superior in image quality, but the gap has been narrowed significantly over the years,” says Chris Mellowship, senior technical sales manager B2B, BenQ UK and Ireland.
caption: Christie 1-chip laser projectors delivered a visual experience at Museum HEI, an art museum in Korea
Yes, the gap has narrowed says Paul Harris, product manager, Digital Projection, whose 1-chip projectors use a pure RGB laser light source. “Modern 1-chip DLP projectors with laser light sources and advanced image processing can deliver excellent image quality that would delight most users.” The quality of new 1-chip models has closed the gap, but not completely says Hartmut Kulesa, head of marketing, Panasonic Visual Systems Europe, “For sure it’s come a long way. The key was speeding up the colour wheel to 14,400 turns per minute as it is now.” Ten years ago, it was hard to find a projector that was 10,000 lumens in the 1-chip space says Joel St-Denis, director of product management, Christie, “Now you have 1-chip models that are in the 20,000-25,000 lumens space that are coming to market.” This has been steered in no small part by what’s driving the projector from the inside from Texas Instruments (TI) he adds.
“We’ve all been using the same DMD’s for a long time, but TI has released some new DMD’s called HEP (High Efficiency Pixel) DMD, which
are smaller, more efficient, less expensive, which is great because it allows the technology to advance. What used to be a 20,000 lumens projector, that was a particular size and price is now 25% smaller, with the same brightness, but it’s more efficient in the power it uses. It’s also got better contrast because these DMD’s have advanced and it’s 25% cheaper. It’s the evolution of technology.” And it won’t stop there adds St Denis, who is bullish about the future of 1-chip: “I believe we’re going to continue to see innovation in 1-chip. There are other things on the horizon that are going to continue to make that platform better and close the gap between the reasons why people buy 3-chip over 1-chip.”
If the gap is closing, and everyone we spoke to agreed it was, then what are the advantages to moving from 3-chip to 1-chip projection? It’s a mix of factors says Harris: “The key benefits of moving to 1-chip projection are a lower price point, smaller size compared to 3-chip models and lower maintenance costs, especially with newer models that use long life laser light sources. Also, 1-chip systems generally consume less power, which is beneficial for energy-conscious users or installations with many units.” Weight is also a key factor says St-Denis: “Ten years ago you needed three people to move a 25,000 lumens projector. Now you’re getting to the point where some of these projectors are 30kg and potentially putting out 15/18/20,000 lumens - something that somebody can actually pick up and move around by themselves. It’s not light, but it’s now an option.”
caption: Digital Projection 1-chip laser projectors were chosen for two French projects, the French Language Museum (above) and the Adidas Arena (below)
The adaptability of 1-chip projectors is also improving says St Denis: “Another change we’ve seen that’s impacted more 1-chip projectors being used in smaller spaces is there’s been a lot of lenses coming out that are either ultra short throw or short throw, so those L-shaped lenses allow you to do.65 to 1 or .8 to 1, so you’re now able to do immersive rooms.”
One criticism of 1-chip projectors was they were susceptible to the rainbow effect, an optical artifact that appears as a quick burst of colours on the screen. Is this still the case or are those days gone? Some 1-chip projectors are more prone to it than others says Mellowship. “It’s something that’s not completely gone and you can’t say 1-chip has erased it because you can go on to an online reseller and buy one of these $99 projectors that promise the world and they are using a colour wheel from 20 years ago. It comes down to the brand and the optical engine and stuff like that, but the technology is there to greatly reduce the occurrence of the rainbow effect.”
It depends on the light source design explains Kulesa, but things are improving. “The rainbow effect was most obvious when you had a high pressure lamp, a stable light source which is always on and produces constant wavelengths of different colours, like a UHP lamp. With lamp technology and a colour wheel that was when the rainbow effect was most obvious. What you see now is a combination of the laser pulsing in combination with the dual wheel design. It reduces the black pauses but also the differences between the colours, so it’s almost eliminated the rainbow effect.”
How does the colour accuracy of new and recent 1-chip projectors measure up to the latest 3-chip projectors? “If you have a primary coloured colour wheel with RGB and white you will have difficulties with the secondary colours,” continues Kulesa. “This is why some vendors are putting in CMYK colour wheels. There are limitations in terms of the colour space and how you’re producing the secondary colours or mixing the colours. This will always be an issue as long as you use your one wavelength of light in your light source. There is potentially a way to remove it by moving to RGB light sources which is something several vendors have showed. We are also looking into this at Panasonic because then that gives you the opportunity to flash or pulse the laser in the way you need it so you can expand the colour.”
As already mentioned, there are some things to prioritise when buying 1-chip projectors so you get exactly what you want, such as accurate colours and brightness. So just what are the trade-offs in colour wheel design for brightness, colour rendition and black levels? “If you have a high brightness efficiency colour wheel you might sacrifice some colour rendition and brightness. If you go full brightness, you’re going to start to wash out your colours, there’s always something,” says Mellowship.
St-Denis says there’s a trade-off between contrast and brightness, and the choice is often application specific. “To get something that has rich colours, better contrast you might be losing half your brightness, so your 10,000 lumens projector now is maybe a 5,000 lumens projector. Certain customers will lap that up, if you’re looking for a projector in a corporate lobby where there’s some ambient light you want as much brightness as possible so that you can actually see the content. Contrast is less of a concern because dark content is less likely to be shown in a lobby. They’re going to have something vibrant, logos, videos of stuff that’s promoting their company.” Colour wheel design in 1-chip projectors is a delicate balancing act between brightness, colour accuracy, and black level performance says Harris. “For example, RGBW wheels add a clear (white) segment to boost brightness, which is great for presentations or bright rooms, but colours can appear washed out, and black levels may suffer due to elevated brightness levels. RGBRGB wheels prioritise colour fidelity by doubling the colour segments, whereas RGBCMY wheels introduce cyan, magenta, and yellow to expand the colour gamut further.”
Finally, with 1-chip projectors getting brighter, lighter, smaller, and more efficient, does this open up new applications that weren’t there before? Absolutely says Kulesa: “As products get brighter and brighter it opens up opportunities to use 1-chip in signage applications, in underground stations, using 1-chip for projects that in the past would have been 3-chip. That makes the application more cost efficient, more affordable, but also more sustainable. I’m also seeing 1-chip being used in immersive experiences and for big screens in digital museums; where probably people were more locked in on a 3-chip 20,000 lumens product, I see now a lot of 10-15,000 lumen 1-chip products deployed into such type of applications.”
This new generation of 1-chip projectors is chipping away at markets that would have previously been 3-chip says St-Denis. “For people who are more critical about colour, such as a museum which is going to be projecting art, or a travelling Van Gogh-type museum, you want the image to look as much like the artwork as possible. There are applications where in the past, when 1-chip was doing the basic colour minimum for Rec. 709, that it may have been not considered for those applications. But now you have projectors that are hitting P3 or Rec. 709 [colour standards] so you’re able to do a lot more colour reproduction. That’s what we expect to see, and I think that’s taken away some of the market from 3-chip.”
Final word goes to Digital Projection’s Paul Harris, “1-chip projectors have expanded into several scenarios previously dominated by 3-chip models or considered out of reach due to performance limitations. For example, business and education use in bright environments, art installations and projection mapping, outdoor projection, simulation and training environments.”
The future for 1-chip models is as bright as the new generation of projectors that are hitting the market it seems.