Abstract

In light-emitting diode (LED) applications, it is becoming a big issue that how to optimize light intensity distribution curve (LIDC) and design corresponding optical component to achieve uniform illumination when distance-height ratio (DHR) is given. A new reversing design method is proposed to solve this problem, including design and optimization of LIDC to achieve high uniform illumination and a new algorithm of freeform lens to generate the required LIDC by LED light source. According to this method, two new LED modules integrated with freeform lenses are successfully designed for slim direct-lit LED backlighting with thickness of 10mm, and uniformities of illuminance increase from 0.446 to 0.915 and from 0.155 to 0.887 when DHRs are 2 and 3 respectively. Moreover, the number of new LED modules dramatically decreases to 1/9 of the traditional LED modules while achieving similar uniform illumination in backlighting. Therefore, this new method provides a practical and simple way for optical design of LED uniform illumination when DHR is much larger than 1.

© 2011 OSA

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References

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2010 (3)

2009 (4)

K. Wang, S. Liu, F. Chen, Z. Qin, Z. Y. Liu, and X. B. Luo, “Freeform LED lens for rectangularly prescribed illumination,” J. Opt. A, Pure Appl. Opt. 11(10), 105501 (2009).
[CrossRef]

F. Chen, S. Liu, K. Wang, Z. Y. Liu, and X. B. Luo, “Free-form lenses for high illuminance quality light-emitting diode MR16 lamps,” Opt. Eng. 48(12), 123002 (2009).
[CrossRef]

A. J. W. Whang, Y. Y. Chen, and Y. T. Teng, “Designing uniform illumination systems by surface-tailored lens and configurations of LED arrays,” J. Disp. Technol. 5(3), 94–103 (2009).
[CrossRef]

H. Yang, J. W. M. Bergmans, T. C. W. Schenk, J.-P. M. G. Linnartz, and R. Rietman, “Uniform illuminance rendering using an array of LEDs: a signal processing perspective,” IEEE Trans. Signal Process. 57(3), 1044–1057 (2009).
[CrossRef]

2008 (2)

2006 (2)

2005 (1)

M. G. Craford, “LEDs for solid state lighting and other emerging applications: status, trends, and challenges,” Proc. SPIE 5941, 1–10 (2005).

2004 (1)

I. Moreno, “Configurations of LED arrays for uniform illumination,” Proc. SPIE 5622, 713–718 (2004).
[CrossRef]

1994 (1)

Avendaño-Alejo, M.

Bergmans, J. W. M.

H. Yang, J. W. M. Bergmans, T. C. W. Schenk, J.-P. M. G. Linnartz, and R. Rietman, “Uniform illuminance rendering using an array of LEDs: a signal processing perspective,” IEEE Trans. Signal Process. 57(3), 1044–1057 (2009).
[CrossRef]

Chen, F.

Chen, Y. Y.

A. J. W. Whang, Y. Y. Chen, and Y. T. Teng, “Designing uniform illumination systems by surface-tailored lens and configurations of LED arrays,” J. Disp. Technol. 5(3), 94–103 (2009).
[CrossRef]

Craford, M. G.

M. G. Craford, “LEDs for solid state lighting and other emerging applications: status, trends, and challenges,” Proc. SPIE 5941, 1–10 (2005).

Ding, Y.

Gu, P. F.

Huang, S. M.

Lee, T. X.

Lee, Y. L.

Linnartz, J.-P. M. G.

H. Yang, J. W. M. Bergmans, T. C. W. Schenk, J.-P. M. G. Linnartz, and R. Rietman, “Uniform illuminance rendering using an array of LEDs: a signal processing perspective,” IEEE Trans. Signal Process. 57(3), 1044–1057 (2009).
[CrossRef]

Liu, S.

Liu, X.

Liu, Z. Y.

K. Wang, D. Wu, F. Chen, Z. Y. Liu, X. B. Luo, and S. Liu, “Angular color uniformity enhancement of white light-emitting diodes integrated with freeform lenses,” Opt. Lett. 35(11), 1860–1862 (2010).
[CrossRef] [PubMed]

K. Wang, F. Chen, Z. Y. Liu, X. B. Luo, and S. Liu, “Design of compact freeform lens for application specific Light-Emitting Diode packaging,” Opt. Express 18(2), 413–425 (2010), http://www.opticsinfobase.org/abstract.cfm?uri=oe-18-2-413 .
[CrossRef] [PubMed]

F. Chen, S. Liu, K. Wang, Z. Y. Liu, and X. B. Luo, “Free-form lenses for high illuminance quality light-emitting diode MR16 lamps,” Opt. Eng. 48(12), 123002 (2009).
[CrossRef]

K. Wang, S. Liu, F. Chen, Z. Qin, Z. Y. Liu, and X. B. Luo, “Freeform LED lens for rectangularly prescribed illumination,” J. Opt. A, Pure Appl. Opt. 11(10), 105501 (2009).
[CrossRef]

Luo, X. B.

Ma, S. H.

Moreno, I.

I. Moreno and C. C. Sun, “LEDs array: where does far-field begin,” Proc. SPIE 7058, 70580R, 70580R-9 (2008).
[CrossRef]

I. Moreno, M. Avendaño-Alejo, and R. I. Tzonchev, “Designing light-emitting diode arrays for uniform near-field irradiance,” Appl. Opt. 45(10), 2265–2272 (2006).
[CrossRef] [PubMed]

I. Moreno, “Configurations of LED arrays for uniform illumination,” Proc. SPIE 5622, 713–718 (2004).
[CrossRef]

Qin, Z.

Rabl, A.

Ries, H.

Rietman, R.

H. Yang, J. W. M. Bergmans, T. C. W. Schenk, J.-P. M. G. Linnartz, and R. Rietman, “Uniform illuminance rendering using an array of LEDs: a signal processing perspective,” IEEE Trans. Signal Process. 57(3), 1044–1057 (2009).
[CrossRef]

Schenk, T. C. W.

H. Yang, J. W. M. Bergmans, T. C. W. Schenk, J.-P. M. G. Linnartz, and R. Rietman, “Uniform illuminance rendering using an array of LEDs: a signal processing perspective,” IEEE Trans. Signal Process. 57(3), 1044–1057 (2009).
[CrossRef]

Sun, C. C.

Teng, Y. T.

A. J. W. Whang, Y. Y. Chen, and Y. T. Teng, “Designing uniform illumination systems by surface-tailored lens and configurations of LED arrays,” J. Disp. Technol. 5(3), 94–103 (2009).
[CrossRef]

Tzonchev, R. I.

Wang, K.

Whang, A. J. W.

A. J. W. Whang, Y. Y. Chen, and Y. T. Teng, “Designing uniform illumination systems by surface-tailored lens and configurations of LED arrays,” J. Disp. Technol. 5(3), 94–103 (2009).
[CrossRef]

Wu, D.

Yang, H.

H. Yang, J. W. M. Bergmans, T. C. W. Schenk, J.-P. M. G. Linnartz, and R. Rietman, “Uniform illuminance rendering using an array of LEDs: a signal processing perspective,” IEEE Trans. Signal Process. 57(3), 1044–1057 (2009).
[CrossRef]

Zheng, Z. R.

Appl. Opt. (1)

IEEE Trans. Signal Process. (1)

H. Yang, J. W. M. Bergmans, T. C. W. Schenk, J.-P. M. G. Linnartz, and R. Rietman, “Uniform illuminance rendering using an array of LEDs: a signal processing perspective,” IEEE Trans. Signal Process. 57(3), 1044–1057 (2009).
[CrossRef]

J. Disp. Technol. (1)

A. J. W. Whang, Y. Y. Chen, and Y. T. Teng, “Designing uniform illumination systems by surface-tailored lens and configurations of LED arrays,” J. Disp. Technol. 5(3), 94–103 (2009).
[CrossRef]

J. Opt. A, Pure Appl. Opt. (1)

K. Wang, S. Liu, F. Chen, Z. Qin, Z. Y. Liu, and X. B. Luo, “Freeform LED lens for rectangularly prescribed illumination,” J. Opt. A, Pure Appl. Opt. 11(10), 105501 (2009).
[CrossRef]

J. Opt. Soc. Am. A (1)

Opt. Eng. (1)

F. Chen, S. Liu, K. Wang, Z. Y. Liu, and X. B. Luo, “Free-form lenses for high illuminance quality light-emitting diode MR16 lamps,” Opt. Eng. 48(12), 123002 (2009).
[CrossRef]

Opt. Express (3)

Opt. Lett. (2)

Proc. SPIE (3)

I. Moreno and C. C. Sun, “LEDs array: where does far-field begin,” Proc. SPIE 7058, 70580R, 70580R-9 (2008).
[CrossRef]

M. G. Craford, “LEDs for solid state lighting and other emerging applications: status, trends, and challenges,” Proc. SPIE 5941, 1–10 (2005).

I. Moreno, “Configurations of LED arrays for uniform illumination,” Proc. SPIE 5622, 713–718 (2004).
[CrossRef]

Other (3)

S. Kobayashi, S. Mikoshiba, S. Lim, and L. C. D. Backlights, (John Wiley and Sons, 2009).

E. F. Schubert, Light-Emitting Diodes (Cambridge University Press, 2006).

S. Liu and X. B. Luo, LED Packaging for Lighting Applications: Design, Manufacturing and Testing (John Wiley and Sons, 2011), (to be published).

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Figures (9)

Fig. 1
Fig. 1

Schematic of square LED light source array and the target plane.

Fig. 2
Fig. 2

Flowchart of this new reversing design method for LED uniform illumination.

Fig. 3
Fig. 3

Schematic of light energy distribution of a light source.

Fig. 4
Fig. 4

Schematic of light energy mapping relationship between the light source and the required LIDC.

Fig. 5
Fig. 5

(a) Optical model of a traditional 0.068W LED module for direct-lit backlighting and (b) its LIDC.

Fig. 6
Fig. 6

Lighting performance of traditional LED modules array on the receiving plane 10mm away when DHR increases from 1 to 3: (a) DHR = 1, U = 0.902, CV(RMSE) = 0.0167; (b) DHR = 2, U = 0.446, CV(RMSE) = 0.2201; and (c) DHR = 3, U = 0.155, CV(RMSE) = 0.5688.

Fig. 7
Fig. 7

(a) Optimized LIDC and (b) its lighting performance on the receiving plane when DHR = 2: U = 0.936, CV(RMSE) = 0.0097.

Fig. 8
Fig. 8

(a) A new LED module integrated with a special silicone gel freeform lens for direct-lit backlighting when DHR = 2, (b) comparison of LIDCs between the simulated and the optimized results, and (c) lighting performance of these new LED modules array, U = 0.915, CV(RMSE) = 0.0128.

Fig. 9
Fig. 9

(a) A new LED module integrated with a special silicone gel freeform lens for direct-lit backlighting when DHR = 3, (b) comparison of LIDCs between the simulated and the optimized results, and (c) lighting performance of these new LED modules array, U = 0.887, CV(RMSE) = 0.0224.

Equations (10)

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I ( θ ) = a 0 + a 1 θ 2 + a 2 θ 4 + a 3 θ 6 + a 4 θ 8
E i ( x , y , z 0 ) = I ( θ i ) cos θ i r i 2 = I ( θ i ) z 0 r i 3 = I ( θ i ) z 0 [ ( x x i ) 2 + ( y y i ) 2 + z 0 2 ] 3 / 2
E ( x , y , z 0 ) = i = 1 M × N E i ( x , y , z 0 )
C V ( R M S E ) = R M S E / x ¯
R ( x j , y j , z 0 ) = E ( x j , y j , z 0 ) E ( 0 , 0 , z 0 )
ϕ i n p u t _ 0 = I i n p u t ( θ ) d ω = γ 1 γ 2 d γ θ 1 θ 2 I i n p u t ( θ ) sin θ d θ
ϕ i n p u t _ 0 = 2 π θ 1 θ 2 I i n p u t ( θ ) sin θ d θ
ϕ i n p u t _ t o t a l = 2 π 0 π / 2 I i n p u t ( θ ) sin θ d θ
2 π θ i n p u t _ k θ i n p u t _ k + 1 I i n p u t ( θ ) sin θ d θ = ϕ i n p u t _ t o t a l B   ( k = 1 , 2 , ... B ,   θ i n p u t _ 1 = 0 )
Δ θ i n p u t _ k + 1 = θ i n p u t _ k + 1 θ i n p u t _ k   ( k = 1 , 2 , ... B )

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