Abstract

The lighting parameters of LEDs are constantly improving. They should not however be applied directly in general lighting luminaires. Luminous intensity distribution solid of high power LEDs is inappropriate for the uniform lighting of a target surface and produces too high of a luminance for this luminaire for large elevation angles. We analyzed the luminous intensity curves allowing us to achieve the best possible lighting uniformity and limited distribution of the luminous flux. Specially manufactured reflectors with limited height were applied in the designed luminaire model. The application of 30 white and additionally six red diodes in the same luminaire provided the resulting optical radiation with the color temperature of 3702  K and a color rendering index of 81.

© 2008 Optical Society of America

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References

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  1. M. R. Krames, O. B. Shchekin, R. Mueller-Mach, G. O. Mueller, Ling-Zhou, G. Harbers, and M. G. Craford, "Status and future of high-power light-emitting diodes for solid-state lighting," J. Disp. Technol. 3, 165-170 (2007).
    [CrossRef]
  2. D. Brown, D. Nicol, and I. Ferguson, "Investigation of the spectral properties of LED-based MR16 bulbs for general illumination," Opt. Eng. 44, 111310 (2005).
    [CrossRef]
  3. Y. Ohno, "Spectral design considerations for white LED color rendering," Opt. Eng. 44, 111302 (2005).
    [CrossRef]
  4. H. Yu Chou, T. H. Hsu, and T. H. Yang, "Effective method for improving illuminating properties of white-light LEDs," Proc. SPIE 5739, 33-41 (2005).
    [CrossRef]
  5. O. Moisio, P. Pinho, E. Tetri, and L. Halonen, "Controlling the color temperature of a LED-luminaire," in Light Sources 2004: Proceedings of the Tenth International Symposium on the Science and Technology of Light Sources, Toulouse, France, 18-22 July 2004, G. Zissis, ed. (Iop., 2004), pp. 375-376.
  6. K. Zaremba, "A synthetic method of designing rotational reflectors," presented at the Thirteenth European Simulation Multiconference 1999, Modelling and Simulation: A Tool for the Next Millenium (ESM 99), Warsaw, Poland, 1-4 June 1999.

2007 (1)

M. R. Krames, O. B. Shchekin, R. Mueller-Mach, G. O. Mueller, Ling-Zhou, G. Harbers, and M. G. Craford, "Status and future of high-power light-emitting diodes for solid-state lighting," J. Disp. Technol. 3, 165-170 (2007).
[CrossRef]

2005 (3)

D. Brown, D. Nicol, and I. Ferguson, "Investigation of the spectral properties of LED-based MR16 bulbs for general illumination," Opt. Eng. 44, 111310 (2005).
[CrossRef]

Y. Ohno, "Spectral design considerations for white LED color rendering," Opt. Eng. 44, 111302 (2005).
[CrossRef]

H. Yu Chou, T. H. Hsu, and T. H. Yang, "Effective method for improving illuminating properties of white-light LEDs," Proc. SPIE 5739, 33-41 (2005).
[CrossRef]

J. Disp. Technol. (1)

M. R. Krames, O. B. Shchekin, R. Mueller-Mach, G. O. Mueller, Ling-Zhou, G. Harbers, and M. G. Craford, "Status and future of high-power light-emitting diodes for solid-state lighting," J. Disp. Technol. 3, 165-170 (2007).
[CrossRef]

Opt. Eng. (2)

D. Brown, D. Nicol, and I. Ferguson, "Investigation of the spectral properties of LED-based MR16 bulbs for general illumination," Opt. Eng. 44, 111310 (2005).
[CrossRef]

Y. Ohno, "Spectral design considerations for white LED color rendering," Opt. Eng. 44, 111302 (2005).
[CrossRef]

Proc. SPIE (1)

H. Yu Chou, T. H. Hsu, and T. H. Yang, "Effective method for improving illuminating properties of white-light LEDs," Proc. SPIE 5739, 33-41 (2005).
[CrossRef]

Other (2)

O. Moisio, P. Pinho, E. Tetri, and L. Halonen, "Controlling the color temperature of a LED-luminaire," in Light Sources 2004: Proceedings of the Tenth International Symposium on the Science and Technology of Light Sources, Toulouse, France, 18-22 July 2004, G. Zissis, ed. (Iop., 2004), pp. 375-376.

K. Zaremba, "A synthetic method of designing rotational reflectors," presented at the Thirteenth European Simulation Multiconference 1999, Modelling and Simulation: A Tool for the Next Millenium (ESM 99), Warsaw, Poland, 1-4 June 1999.

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Figures (12)

Fig. 1
Fig. 1

Geometric layout of the luminaire with a luminous intensity curve for uniform lighting.

Fig. 2
Fig. 2

Maximum luminous intensity I o 0 for the luminaire as a function of cutoff angle α o b of direct irradiation of the luminous flux.

Fig. 3
Fig. 3

Geometric layout of the designed luminaire with alternated luminous intensity curve.

Fig. 4
Fig. 4

Assumed relative illuminance distribution on the target area ( E 0 , illuminance value on the target area directly under the luminaire).

Fig. 5
Fig. 5

Relation between the cutoff angle α o x of the variation in the luminous intensity distribution solid and the α o b angle of direct irradiation of the luminaire.

Fig. 6
Fig. 6

Relation between the lighting uniformity index δ for the examined target area and the cutoff angle α o b for the direct irradiation of the luminaire.

Fig. 7
Fig. 7

Calculated color temperature T c for radiation mix originating from a single red and n W white diodes.

Fig. 8
Fig. 8

Calculated color rendering index CRI for radiation mix originating from a single red and n W white diodes.

Fig. 9
Fig. 9

Schematic of the flux method for determining the: (a) reflector profile and (b) calculated shape for the rotationally symmetrical reflector with the direct irradiation angle α o b equal to 55°.

Fig. 10
Fig. 10

Image of the profile of the calculated reflector.

Fig. 11
Fig. 11

(Color online) Overall construction of the model luminaire with 36 LEDs.

Fig. 12
Fig. 12

Luminous intensity curve of the luminaire model.

Equations (18)

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I o α = I o 0 cos 3 α ,
Φ o = 2 π 0 α o b I o α sin α d α = 2 π I o 0 0 α o b sin α cos 3 α d α = π I o 0 tan 2 α o b .
I o 0 = Φ o π tan 2 α o b .
I z α = I z 0 cos α = Φ z π cos α ,
Φ o b = 2 π 0 α o b I z α sin α d α = 2 π Φ z π 0 α o b cos α sin α d α = Φ z sin 2 α o b .
Φ r = Φ z Φ o b = Φ z Φ z sin 2 α o b = Φ z cos 2 α o b .
Φ o = Φ o b + ρ Φ r = Φ z sin 2 α o b + ρ Φ z cos 2 α o b .
Φ z sin 2 α o b 0 + ρ Φ z cos 2 α o b 0 = π I o 0 tan 2 α o b 0 = π Φ z π tan 2 α o b 0 = Φ z tan 2 α o b 0 .
( 1 ρ ) sin 4 α o b 0 + 2 ρ sin 2 α o b 0 ρ = 0 ,
sin 2 α o b 0 = ρ ρ 1 ρ .
Φ o 0 x = Φ z sin 2 α o x ,
E x = I o x h 2 cos 3 α o x = Φ z π h 2 cos 4 α o x ,
Φ o x b = Φ z cos 4 α o x ( tan 2 α o b tan 2 α o x ) .
Φ z sin 2 α o b 0 + ρ Φ z cos 2 α o b 0 = Φ z sin 2 α o 0 x + Φ z cos 4 α o 0 x × ( tan 2 α o b 0 tan 2 α o 0 x ) ,
( 1 + tan 2 α o b 0 ) cos 4 α o x 2 cos 2 α o x + 1 sin 2 α o b 0 ρ sin 2 α o b 0 = 0.
E av = Φ o π h 2 tan 2 α o b ,
δ = E min E av = Φ z π h 2 cos 4 α o x Φ o π h 2 tan 2 α o b = Φ z Φ o cos 4 α o x tan 2 α o b = cos 4 α o x tan 2 α o b sin 2 α o b + ρ cos 2 α o b .
2 π ρ α o b + ( i 1 ) Δ φ α o b + i Δ φ I z α sin α d α = 2 π α i α i + Δ α i I r α sin α d α .

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