LED light engine concept with ultra-high scalable luminance

Hoelen, Christoph; Boer, Dick de; Bruls, Dominique; Eyden, J. van der; Koole, Rolf; Liu, Xinyi; Mirsadeghi, Mo; Vanbroekhoven, Vincent; Bergh, John-John Van den; Voorde, Patrick Van de

doi:10.1117/12.2224042

Cited by 5 publications

(12 citation statements)

References 3 publications

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“…Thanks to the thermal pad of the pump LEDs, which is connected with metallic vias to the metal core of the circuit board carrying the LEDs, the LEDs can be driven at forward currents up to even significantly more than 3 A without resulting in extremely high junction or solder temperatures. Excellent reliability of this configuration has been reported [8].…”

Section: Green Hld Sourcementioning

confidence: 84%

“…In doing so, the law of conservation of étendue can be used as a guideline. For a typical Digital Light Processing (DLP) projector with a 0.65" display panel, the étendue requirement for the light source is close to 17 mm 2 sr [8]. The étendue at the entrance of the CPC (and just inside it) is ε = n CPC 2 A in π, where the factor π arises from the fact that the light escaping from the rod into the CPC extends a cone with a half-angle of 90 o .…”

Section: Principlementioning

confidence: 99%

“…A proper choice of the luminescent material is very important. For an HLD source, the material should be able to withstand high temperatures and fluxes, as well as compliant to other criteria that are essential in projection systems [8]. A good choice is a garnet like cerium-doped yttrium aluminium garnet (YAG:Ce), which is widely used for lighting applications.…”

Section: Principlementioning

confidence: 99%

“…A DLP projection system with a single 0.65"WXGA panel was built with three color sources [8]. For the red and blue color channels, very high-power LEDs are applied, tuned in size to match reasonably well the system étendue.…”

Section: Projection Systemmentioning

confidence: 99%

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LED-based projection source based on luminescent concentration

et al. 2016

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The concept of an LED-based source with high lumen density is described. It contains a luminescent rod in which LED light is converted to light with a longer wavelength that is extracted from a small face of the rod. The fundamental limitations and possibilities are discussed, as well as the constituents needed. Results are shown for two realized high lumen density sources. A source with YAG:Ce as phosphor is extensively characterized and the results are compared to modeling results. A source with an optimized green emitting phosphor is used for projection. With 64 pump LEDs at 490 W peak electrical input and 50% duty cycle, a peak luminous flux of 18000 lm and a peak luminance of over 1000 cd/mm 2 is obtained, with an efficacy of 37 peak lm/W.

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Section: Green Hld Sourcementioning

confidence: 84%

Section: Principlementioning

confidence: 99%

Section: Principlementioning

confidence: 99%

Section: Projection Systemmentioning

confidence: 99%

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LED-based projection source based on luminescent concentration

et al. 2016

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“…Moreover, both discharge lamps and laser-based sources degrade relatively fast. Recently [1][2][3][4][5], we developed a new type of LED-based light source, the high lumen density (HLD) source, which is very stable and enables the mentioned applications (luminance > 2·10 9 cd/m 2 ). Similar concepts were investigated by others [6,7].…”

Section: Introductionmentioning

confidence: 99%

Extraction optics for high lumen density sources

Boer

Haenen

2019

J. Eur. Opt. Soc.-Rapid Publ.

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For lighting applications demanding high brightness, a new type of LED-based light source has been developed, the high lumen density (HLD) source (luminance > 2·10 9 cd/m 2 ). The performance can be improved further, among other things by optimizing the concentrator used as extraction optics. For this optimization, much insight is obtained by ray-tracing simulations. The efficiency can be improved by more than 20% if a high-index concentrator could be used. Furthermore, it is possible to optimize the shape of the concentrator. For a low-index (n ≈ 1.5) concentrator, the light leakage can be reduced, but the gain in useful light is only marginal. For a high-index (n ≈ 1.8) concentrator, the gain in useful light amounts to a few percent.

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Photosaturation in Luminescent LuAG:Ce Garnet Concentrator Rods

Khanin

Meijerink

Houtepen

et al. 2021

Advanced Photonics Research

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The luminescence efficiency of Ce3+ in garnet phosphors is among the most stable for luminescent materials. Still, it has been observed to be reduced at high incident blue flux (known as droop) due to nonlinear processes caused by the high lumen density inside the materials. Herein, it is shown that in the case of Ce3+‐doped garnet concentrator rods, the droop can be explained by excited‐state absorption (ESA) of mainly green Ce3+ luminescence light that is trapped inside the rods. ESA spectroscopy and thermally stimulated luminescence (TSL) measurements show that electrons are promoted from the 5d1 excited state of Ce3+ to the conduction band by ESA and may be either captured by traps or may recombine with Ce4+ sites to give excited Ce3+ ions giving rise to luminescence. Therefore, the droop depends on the concentration of Ce4+ ions present, which can be influenced and optimized by varying the processing conditions of the samples. Guided by these results, a model is developed that describes the optical processes. It is used to analyze the observed droop behavior in block‐shaped samples with and without extraction optics.

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LED light engine concept with ultra-high scalable luminance

Cited by 5 publications

References 3 publications

LED-based projection source based on luminescent concentration

LED-based projection source based on luminescent concentration

Extraction optics for high lumen density sources

Photosaturation in Luminescent LuAG:Ce Garnet Concentrator Rods

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