As you have been reading in our series of articles, laser-based
projection causes both an evolution and a revolution in the world of
cinema. Throughout history, a lot of practicalities have made
(r)evolutions happen. In this article we will focus on the practicalities of installing and operating a laser-illuminated projector in a digital cinema context.
We will give you a glimpse into the little and big adventures our
installers and end users experience; as well as provide some answers to
frequently asked questions. One of them being a question we asked
ourselves: “Who are those two Germans and what are they trying to do
with that projector?”
When talking about the practicalities of installing and operating laser-based projectors in cinemas, it is important to make a distinction between laser phosphor and RGB laser projectors. The latter, such as Barco’s DP4K-L series, have been introduced to create a true revolution in cinema. They not only enable light outputs that double the brightness levels of lamps, they also dramatically improve contrast, uniformity, and stability – creating a whole new class of image quality. Barco’s flagship laser projectors are the result of a long-term platform development that created the ultimate projector – built from the ground up. Their performance, properties, and handling deserve some special attention.
On the other hand, laser phosphor illuminated projectors were introduced more recently - we launched our DP2K-15CLP and DP2K-20CLP offering brightness levels up to 18,000 lumens at CineAsia 2015. They represent a more natural evolution in cinema – just like the move from incandescent lamps to LED lighting in the home – and laser phosphor will soon make an end to costly and cumbersome lamp swaps in cinema. They are not only available as new-built projection setups, but also as fast and easy field retrofits. Let there be no misunderstanding: laser phosphor does enable better image quality (through contrast, uniformity…) but its installation and operation is designed to be similar to a ‘standard’ lamp-based projector. With one small detail: you never have to swap a lamp again.
In the rest of this article we’ll focus on the practicalities of RGB laser projectors; since the differences are most noticeable there.
A first parameter that sets RGB flagship laser projectors apart is their size (and weight). Since they have been designed for ultimate image quality and brightness; every aspect of the setup has been dimensioned to combine this performance with stability and reliability. On the one hand there is the projection head: you need a certain space (a.k.a. ‘étendue’) to support 4K chip size of the internal optics.
The fact that Barco’s DP4K-L projectors are the only ones to have an integrated light source is also important. The direct coupling of integrated light sources offers a much higher efficiency than so-called fiber coupling, but it also contribute to the total projection head size.
The critical and accurate cooling is enabled by ‘chillers’: these active cooling elements keep the laser temperatures under control. This is how we manage to reach performance levels of less than 20% light drop over 30,000 hours. Of course these chillers also add to the total system. Barco’s DP4K-60L, the world’s brightest projector with 56,000 lumens light output, has a projection head size of 744 x 1,445 x 706 mm (29.3 x 56.9 x 27.8 inches). The two chillers, each measure 701 x 701 x 800 mm (27.6 x 27.6 x 31.5 inches). The total system weighs just above 500kg.
A second set of parameters with a practical impact on installation and operation have to do with laser safety. These were explained in-depth in a recent article by LIPA Chairman Jan Daem. It is important to understand that these standardized metrics (restricted access location, restriction zone, separation height, separation width…) can have an impact on your booth and auditorium layout. To answer the questions for your specific setup – such as: “do I have to remove seats in the back of my auditorium due to separation height limits?” – you can best contact your local regulation body, since the standards vary per region.
The next parameters that need to be taken into account kick in when the installation is done and when you’re ready to run your day-to-day business. They have to do with the operational conditions of RGB laser projectors. As mentioned above, these high brightness projectors are built from the ground up for ultimate performance. When you have a unit that emits double the amount of light, it is logical that you’ll have to dimensions your electrical power supply accordingly. Do note however that laser illumination does allows for much higher light efficiencies (lumen/Watt). In the case of Barco DP4K-60L projector you’ll draw just below 10kW of electrical power to generate almost 60,000 lumens of light – including the power consumption of the chiller. Note that you would be drawing 30% more when trying to do the same with lamp-based projectors.
As mentioned above: well-designed and well-operated cooling has a major impact on laser lifetime and performance. A Xenon lamp is pretty comparable to an open fire: it generates a lot of heat – and light in all directions. As long as you foresee fuel to the fire and a way out for the heat, it will continue to burn. Lasers have evolved more towards the world of electronics. Here, it’s important to keep the modules at a low and stable temperature. That is why so much effort was invested in the cooling, which is very tangible through the chillers.
Practical implementations for your checklist are here:
The examples above do not provide an exhaustive list on how to install and run an RGB laser projector. We only want to give you a heads-up on the fact that laser illumination provides a shift in many ways: in mindset, work, and thinking. The only thing we can say is that we’ve identified – based on our market lead
