Introduction – LIPA’s Communications Working Group (CWG) Identified the topic of Laser Engine Architecture as an important subject for a technology update Webinar in 2023.
Title: Evolution, Status and Applications of Laser Light Engines for Projection
August 3, 2023, 06:30-0800 US Pacific time
54 people attended representing all LIPA members
Our LIPA Member Speakers
Zuqiang Guo
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Director R&D – Laser Device and Laser Light Source, Appotronics
Lead off with a review of terminology, the evolution of Laser diodes and Laser-pumped phosphor architectures over the past 10 years; current status and the direction of future developments and applications.
Eric Vieth
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Sr. Product Developer, Projection Engineering, Christie Digital
Focused on “direct” RGB architectures, the rationale for their use, current status, and future development.
Goran Stojmenovik, Ph.D.
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Director R&D, Barco NV
Presented Barco’s “agnostic path” for engine architecture development and describe how different approaches can best support an expanding range of application requirements.
Tom Bert, Ph.D.
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VP Product, Barco NV
Wrapped up the presentations with a discussion of current status and a new types of laser sources, spatial light modulation and engine architectures to support new high dynamic range (HDR) applications.
Major Takeaways
- Both major architectures, “Pure” RGB and Laser-Phosphor “La-Ph”, have been under development for nearly 20 years with commercialization beginning around 2008 for La-Ph and 2014 for Cinema RGB
- RGB is used primarily for large screen Cinema and Professional applications
- Highest possible lumen output (75K+) with widest color gamut (near Rec 2020)
- Required for efficient fiber coupling for ultra-high brightness or remote source/modular systems
- Required for special “Cascaded” HDR and High Contrast systems enabled by high f# (small étendue) Laser input.
- Lower output RGB engines are finding applications where they can enable both brightness and resolution from a smaller SLM chip.
- Original Blue Laser Pumped Phosphor (BPP) has evolved into many special architectures, with direct Red, Green and Blue diode “boost” to achieve a target mix of performance optimizations such as higher lumen output, wider gamut, speckle mitigation/reduction, higher wall plug efficiency etc.
- Care must be taken when comparing efficiency metrics (i.e., lm/W), as these can be affected by gamut primaries, white-point, cooling system design, expected lifetime and other system level differences. (Wall plug efficiency should always be considered in the context of other performance metrics.)
- All speakers mentioned that operating efficiency (lm/wall plug watt) has become a very important performance metric for Cinema Projectors and all high duty cycle applications due to the recent and rapid increases in power costs.
- A new type of architecture called “light Steering” was described, where additional RGB light is efficiently added to the base laser-illumination with a spatially controlled distribution, increasing the dynamic range and maximum pixel brightness of the final image.
LIPA will hold a companion Tech Webinar on Wide Color Gamut/Volume September 28, 2023, open to members and the A/V public.