Lasers in cinema: a new shade of green

Posted by (@Tom_Bert) in Cinema

Green laser
Last week, I had to buy a new light bulb for my hallway. I have a sneaky suspicion that my 4-year-old son’s love of playing with the light switch has something to do with the fact that the lamp died on me less than five years after its installation. Anyhow: during shopping for light bulbs for the first time in a while, I was confronted with the new European legislation that forbids incandescent lamps. 

The new kid on the block 

LED is now the new kid on the block. Some years ago, the EU ruled that LED lighting not only benefits the environmental impact but also has a positive effect on the total cost of ownership for the end user. And indeed: for less than €4 I bought myself an LED light bulb that neatly fitted in my hallway lamp. Calculating back the supplier’s lifetime specs with the number of hours per day we light up our hallway, it was probably the last time I ever climbed on a ladder to replace that lamp again. Who would have believed 15 years ago – when I had a nice collection of spare incandescent bulbs in the house, ready to light up any room that turned dark – that our view on a simple thing like lighting would change so significantly? Back then, LED was still a somewhat exotic technology for special use cases. But thanks to the technological evolution and some governmental stimulation, here we are: I never have to replace any lamps anymore.

Green light source

This made me reflect on the current situation the cinema industry is in. For the past 100 years, projectionists have been replacing lamps and theater managers have been boxing up these big bulbs in their booths. It seems strange that an evolution that has become standard at home, is not finding its way into cinema: when will the last lamp be replaced there? With the introduction of laser illumination, this moment is closer than ever before. The benefits of laser projection have been described and presented in many other articles: higher brightness, wider color gamut, longer lifetime etc. 

In this article, I would like to focus on one specific aspect that has not been sufficiently highlighted: laser light sources in cinema are green! Yes, they’re also available in many other colors, but in this context we’d like to elaborate on the ecological aspect of laser lighting for cinema projection, the positive impact on the environment that is. This is the same parameter that drove LED home lighting (via governmental support) towards 100% adoption. Let’s see if a similar scenario is likely to happen in cinema.

Monthly production of a small nuclear plant

The optical efficiency of a cinema laser projector can be between 5% and 60% higher than a lamp-based projector with the same brightness which can be quantified as wall plug efficiency, in lumen per watt (lm/W). This means that for the same amount of lumens on the screen, I need to pull less electrical watts out of wall. 
  

We did an analysis of what the consequences for the European cinema market could be. Taking into account the screen size mix in Europe – and hence the mix between high, medium, and low brightness projectors – and the screening hours, we found that a mind-blowing 700GWh is consumed per year by the European cinema projectors! Yes, that is Giga Watt hours! If we would replace every lamp-based cinema projector by its equivalent laser-illuminated version; this number would drop by 150GWh. That is the equivalent production of a small nuclear power plant in one month! Note that if we would do the same for the worldwide cinema market, results would be between 3 to 5 times higher!

1 million lamp swaps less

Reduced power consumption is not the only ecological impact we would achieve. Digital cinema projector lamps are being replaced between every 500 to 3,000 hours, depending on the screen size. For every lamp that needs to be replaced a pretty big box is shipped to the cinema. Again, based on an analysis of the European cinema market, we found that 150.000 of these lamps are being swapped and sent around on an annual basis. That’s around 100 trucks filled with lamps driving around Europe, every year! Barco’s flagship RGB laser projector runs up to 30,000 hours with an expected light drop of only 20%. This means that if we replace every lamp-based cinema projector by such an RGB laser projector, we avoid over 1 million lamp swaps in Europe! Again, doing the same analysis on a worldwide basis would yield the number 3 to 5 times higher: this is a lots of transport costs, packaging waste, and pollution that can be reduced.

Make the switch

The two numbers we’ve put forward above are just some examples of the potential ecological impact of laser illumination for cinema projectors. We didn’t touch on such topics as hazardous waste (did you know Xenon lamps contain radio-active material?). The 100% conversion we use in our analysis might seem unrealistic when thinking about RGB lasers, as they are used for high-brightness laser projectors such as Barco’s DP4K-L series. However, just recently (at CineAsia 2015) Barco announced its laser phosphor family of new-built and retrofit solutions which are designed to easily convert any auditorium to laser. Now, laser illumination has become a reality – both technically and economically - for all exhibitors on all screens!

We realize that the ecological aspects we discussed in this article might be least of your concerns as an exhibitor. But apart from the other more tangible benefits of laser in cinema some stakeholders DO care about the green aspect of technology. Just remember: less than 10 years ago we were still changing incandescent bulbs in our hallway. Let’s talk again in 10 years at a cinema event…

About the author

Tom Bert
Tom Bert is a senior member of the Product Management team in Barco’s Entertainment division; he is responsible for the digital cinema servers and projectors. Tom joined Barco in 2006 as Research Engineer for Barco’s Technology Center. In 2009, he joined the Product Management team in the Digital Cinema division. Since 2015, Tom has been actively working on digital cinema servers and projectors and he has been promoted to Sr. Product Manager. Based in Belgium, Tom has international experience in display technology. He holds a PhD degree in Engineering from Ghent University.

Related news