Increased lumens per étendue by combining pulsed light-emitting diodes

Murat, Hüseyin; Smet, Herbert De; Cuypers, Dieter; Meuret, Youri; Thienpont, Hugo; Vervacke, Michael; Desmet, Lieven

doi:10.1117/1.2186036

Cited by 8 publications

(6 citation statements)

References 1 publication

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“…Now the increased brightness can be added up in time and will generate a higher average brightness. By applying this technique 1 we achieved a substantial net gain of 36% with Luxeon LEDs. This gain is strongly depending on the type of LEDs and PBS.…”

Section: Green Channelmentioning

confidence: 99%

“…In the previous section (table 1) we saw that the simulation results of the designed GTLP were promising. We fabricated 7 these components in quadruple (one per LED) and measured the performances experimentally.…”

Section: Figure 5: Two-lcos Demonstratormentioning

confidence: 99%

“…The maximum allowed angle in this system is 10º. This component introduces a loss 1 The throughput of the LCOS panels in the simulation model is assumed to be 65% (90% fill factor, 4% absorption by the liquid crystal and 75% reflection coefficient). In the setup, we used QXGA LCOS panels from Gemidis.…”

Section: Figure 5: Two-lcos Demonstratormentioning

confidence: 99%

“…This progress makes it recently interesting to use these devices as light sources for projection applications. Compared with traditional light sources, for example the mercury arc discharge lamps, LEDs have numerous advantages 1,2 . They are small and robust, have a longer lifetime, exhibit a relatively narrow spectral emission band, resulting in a larger color gamut, and are directly available in R, G, B colors; the supply voltage is lower, they can switch on and off very rapidly, have a high dimming ratio that can be used to improve the contrast, they emit no UV, do not contain dangerous mercury etc.…”

Section: Introductionmentioning

confidence: 99%

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Two LCOS full color projector with efficient LED illumination engine

et al. 2009

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LED-based projectors have numerous advantages compared to traditional projectors. They are more compact, exhibit a larger color gamut and a longer lifetime, the supply voltage is lower and they can operate on batteries. However their light output is limited by the low optical power per étendue of the LEDs, although this is also improving constantly. With an efficient illumination engine design we can build an LED projector with a moderate light output and with superior properties. We present a compact LED projector with two 'Liquid Crystal On Silicon' (LCOS) panels. One of these panels is alternately modulating red and blue information while the other permanently modulates the green information to achieve the D65 white point. This architecture is first simulated using ray-tracing software. After testing the several parts of this architecture experimentally, we have built a demonstrator setup. Our demonstrator produces a moderate light output (37.3 lm) on screen with a sufficient contrast ratio and a very good uniformity, within a system étendue lower than 20 mm 2 sr. In spite of semi color sequential working, the color breakup and crosstalk are negligible.

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Section: Green Channelmentioning

confidence: 99%

Section: Figure 5: Two-lcos Demonstratormentioning

confidence: 99%

Section: Figure 5: Two-lcos Demonstratormentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Two LCOS full color projector with efficient LED illumination engine

et al. 2009

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“…Compared with traditional light sources, for example the mercury arc discharge lamps, LEDs have numerous advantages. 1,2 They are small and robust, have a longer lifetime, and exhibit a relatively narrow spectral emission band, resulting in a larger color gamut. Their supply voltage is lower, they can switch on and off very rapidly, and they have a high dimming ratio that can be used to improve the contrast etc.…”

Section: Introductionmentioning

confidence: 99%

Two liquid crystal on silicon panel projector with efficient light-emitting diode illumination engine

et al. 2007

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LED-based projectors have numerous advantages compared to traditional projectors. They are more compact, they exhibit a larger color gamut and a longer lifetime, the supply voltage is lower and they can even operate on batteries. LEDs can switch rapidly ͑possibility to pulse͒ and they have a high dimming ratio ͑contrast considerations͒. However, they have low optical power per étendue, although this is also improving consistently. With an efficient illumination engine design we can build an LED projector with a moderate light output and with superior properties. We present a relatively compact LED projector with two liquid crystal on silicon ͑LCOS͒ light valves ͑LVs͒. One of these LVs alternately modulates red and blue information, while the other permanently modulates green information to achieve a good color balance. Additionally, we apply some methods to increase the brightness on the screen. Our two-LCOS approach results in a compact, efficient LED projector that produces 171 lm projected D65 flux.

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