Abstract

To abandon restrictions from the multiple and irregular radiation patterns of many existing LED products, the free-form microlens optics is designed based on Snell's law and the "edge-ray principle." This secondary optics can redistribute any LED radiation onto the target surfaces to achieve prescribed uniform illuminations without concern for the initial radiation patterns of LED sources. According to practical illumination requirements, the surface shape of the single free-form microlens can be calculated by using the ray tracing method and B-spline fitting. Some modules of free-form microlens optics were constructed to achieve rectangular illumination as well as other styles of illumination. The simulation results show that the illumination achieved has high uniformities and precise illuminating shapes as prescribed. The free-form microlens optics is very applicable in LED lighting, with cogent competitive advantages.

© 2009 Optical Society of America

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References

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2004

P. Zhou, W. Lu, Y. X. Lin, Z. R. Zheng, H. F. Li, and P. F. Gu, “Fly eye lens array used in liquid crystal projection display with high light efficiency,” Acta Opt. Sin. 24, 587-591 (2004), in Chinese.

2002

T. L. R. Davenport, “3D NURBS representation of surface for illumination,” Proc. SPIE 4832, 293-301 (2002).

H. Ries and J. Muschaweck, “Tailored freeform optical surfaces,” J. Opt. Soc. Am. A 19, 590-595 (2002).
[CrossRef]

2001

H. Ries and J. Muschaweck, “Tailoring freeform lenses for illumination,” Proc. SPIE 4442, 43-50 (2001).

1998

W. A. Parkyn, “The design of illumination lenses via extrinsic differential geometry,” Proc. SPIE 3428, 154-162(1998).

1997

Y. He, M. Rea, A. Biemlan, and J. Bullough, “Evaluating light source efficacy under mesopic conditions using reaction times,” J. Illum. Eng. Soc. 26, 125--138 (1997).

1994

1957

Biemlan, A.

Y. He, M. Rea, A. Biemlan, and J. Bullough, “Evaluating light source efficacy under mesopic conditions using reaction times,” J. Illum. Eng. Soc. 26, 125--138 (1997).

Bullough, J.

Y. He, M. Rea, A. Biemlan, and J. Bullough, “Evaluating light source efficacy under mesopic conditions using reaction times,” J. Illum. Eng. Soc. 26, 125--138 (1997).

Chaves, J.

J. Chaves, Introduction to Nonimaging Optics (Taylor & Francis, 2008).

Davenport, T. L. R.

T. L. R. Davenport, “3D NURBS representation of surface for illumination,” Proc. SPIE 4832, 293-301 (2002).

Davies, P. A.

di Toraldo, G. F.

Ding, Y.

Gu, P.

Gu, P. F.

P. Zhou, W. Lu, Y. X. Lin, Z. R. Zheng, H. F. Li, and P. F. Gu, “Fly eye lens array used in liquid crystal projection display with high light efficiency,” Acta Opt. Sin. 24, 587-591 (2004), in Chinese.

He, Y.

Y. He, M. Rea, A. Biemlan, and J. Bullough, “Evaluating light source efficacy under mesopic conditions using reaction times,” J. Illum. Eng. Soc. 26, 125--138 (1997).

Li, H. F.

P. Zhou, W. Lu, Y. X. Lin, Z. R. Zheng, H. F. Li, and P. F. Gu, “Fly eye lens array used in liquid crystal projection display with high light efficiency,” Acta Opt. Sin. 24, 587-591 (2004), in Chinese.

Lin, Y. X.

P. Zhou, W. Lu, Y. X. Lin, Z. R. Zheng, H. F. Li, and P. F. Gu, “Fly eye lens array used in liquid crystal projection display with high light efficiency,” Acta Opt. Sin. 24, 587-591 (2004), in Chinese.

Liu, X.

Lu, W.

P. Zhou, W. Lu, Y. X. Lin, Z. R. Zheng, H. F. Li, and P. F. Gu, “Fly eye lens array used in liquid crystal projection display with high light efficiency,” Acta Opt. Sin. 24, 587-591 (2004), in Chinese.

Luo, K. Q. Y.

Muschaweck, J.

H. Ries and J. Muschaweck, “Tailored freeform optical surfaces,” J. Opt. Soc. Am. A 19, 590-595 (2002).
[CrossRef]

H. Ries and J. Muschaweck, “Tailoring freeform lenses for illumination,” Proc. SPIE 4442, 43-50 (2001).

Parkyn, W. A.

W. A. Parkyn, “The design of illumination lenses via extrinsic differential geometry,” Proc. SPIE 3428, 154-162(1998).

Piegl, L.

L. Piegl and W. Tiller, The NURBS Book, 2nd ed. (Springer-Verlag, 1997).

Rabl, A.

Rea, M.

Y. He, M. Rea, A. Biemlan, and J. Bullough, “Evaluating light source efficacy under mesopic conditions using reaction times,” J. Illum. Eng. Soc. 26, 125--138 (1997).

Ries, H.

Ronchi, L.

Salomon, D.

D. Salomon, Curves and Surfaces for Computer Graphics (Springer, 2006).

Tiller, W.

L. Piegl and W. Tiller, The NURBS Book, 2nd ed. (Springer-Verlag, 1997).

Wang, L.

Welford, W. T.

W. T. Welford and R. Winston, High Collection Non-Imaging Optics (Academic, 1989).

Winston, R.

W. T. Welford and R. Winston, High Collection Non-Imaging Optics (Academic, 1989).

Zheng, Z.

Zheng, Z. R.

P. Zhou, W. Lu, Y. X. Lin, Z. R. Zheng, H. F. Li, and P. F. Gu, “Fly eye lens array used in liquid crystal projection display with high light efficiency,” Acta Opt. Sin. 24, 587-591 (2004), in Chinese.

Zhou, P.

P. Zhou, W. Lu, Y. X. Lin, Z. R. Zheng, H. F. Li, and P. F. Gu, “Fly eye lens array used in liquid crystal projection display with high light efficiency,” Acta Opt. Sin. 24, 587-591 (2004), in Chinese.

Acta Opt. Sin.

P. Zhou, W. Lu, Y. X. Lin, Z. R. Zheng, H. F. Li, and P. F. Gu, “Fly eye lens array used in liquid crystal projection display with high light efficiency,” Acta Opt. Sin. 24, 587-591 (2004), in Chinese.

Appl. Opt.

J. Illum. Eng. Soc.

Y. He, M. Rea, A. Biemlan, and J. Bullough, “Evaluating light source efficacy under mesopic conditions using reaction times,” J. Illum. Eng. Soc. 26, 125--138 (1997).

J. Opt. Soc. Am.

J. Opt. Soc. Am. A

Opt. Express

Proc. SPIE

T. L. R. Davenport, “3D NURBS representation of surface for illumination,” Proc. SPIE 4832, 293-301 (2002).

H. Ries and J. Muschaweck, “Tailoring freeform lenses for illumination,” Proc. SPIE 4442, 43-50 (2001).

W. A. Parkyn, “The design of illumination lenses via extrinsic differential geometry,” Proc. SPIE 3428, 154-162(1998).

Other

L. Piegl and W. Tiller, The NURBS Book, 2nd ed. (Springer-Verlag, 1997).

D. Salomon, Curves and Surfaces for Computer Graphics (Springer, 2006).

“LUXEON radiation patterns,” PHILIPS LUMILEDS LED products technology (Philips Lumileds Lighting,, San Jose, Calif., 2009), http://www.philipslumileds.com/technology/radiationpatterns.cfm.

W. T. Welford and R. Winston, High Collection Non-Imaging Optics (Academic, 1989).

J. Chaves, Introduction to Nonimaging Optics (Taylor & Francis, 2008).

R. Winston, J. C. Miñano, P. Benítez, N. Shatz, and J. C. Bortz, eds., Nonimaging Optics (Elsevier, 2005).

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Figures (10)

Fig. 1
Fig. 1

Schematic ray path and structure of the microlens free-form optics design for LED illuminations.

Fig. 2
Fig. 2

Schematic ray tracing under the refraction (reflection) condition.

Fig. 3
Fig. 3

(a) Schematic tailoring of the overall collimated radiation from the TIR cup. The surface shape of the TIR cup and the spatial distribution of collimated radiation are not real, they are just a visual aid. (b) The schematic radiation transmission process through the single microlens.

Fig. 4
Fig. 4

Schematic ray tracing of the "edge ray principle" on the microcell (all the lengths of line are arbitrary, and the drawing is not to scale). All the redistributed light rays through the nodes of the microcell are drawn as dashed lines.

Fig. 5
Fig. 5

(a) Surface shaping of the single free-form microlens. (b) Magnified structure of the final designed free-form microlens array. (c) Simulated ray path in the designed optics module.

Fig. 6
Fig. 6

(a) Radiation pattern of the source used in this simulation, which is one typical non-Lambertian radiation pattern of the LED. (b) Simulated rectangular high uniform illumination on the target surface using a non-Lambertian radiation source.

Fig. 7
Fig. 7

(a) Radiation pattern of the source used in this simulation, which denotes the typical Lambertian LED products. (b) Simulated prescribed rectangular high illumination on the target surface using a Lambertian radiation source.

Fig. 8
Fig. 8

Simulated distribution of the illumination as shown in Fig. 6b, which uses a non-Lambertian radiation LED source. (b) Corresponding line distribution along the x axis across the center of the illumination. (c) Line distribution along the y axis across the center of the illumination.

Fig. 9
Fig. 9

Simulated distribution of the illumination as shown in Fig. 7b, which uses Lambertian radiation LED source. (b) Line distribution along the x axis across the center of the illumination. (c) Line distribution along the y axis across the center of the illumination.

Fig. 10
Fig. 10

(a) Round illumination achieved by free-form microlens secondary optics. (b) Hexagonal illumination achieved by free-form microlens secondary optics.

Tables (1)

Tables Icon

Table 1 Locations and Unit Normals of Typical 15 Points on the Calculated Free-Form Surface of the Microlens

Equations (10)

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I = I 2 ( N · I ) N .
n O × N = n I × N ,
N = I O | I O | .
A E f d s = i = 1 N C i E i d s = E total ,
I i , j = ( I i , j , x i , I i , j , y j , I i , j , z k , ) ,
O i , j = ( O i , j , x i , O i , j , y j , O i , j , z k , ) ,
N i , j = ( N i , j , x i , N i , j , y j , N i , j , z k , ) .
I i , j = ( 0 , 0 , n · k , ) ,
O i , j = 1 ( L 2 ( i M + 1 1 2 ) 2 + W 2 ( j N + 1 1 2 ) 2 + R 2 ) 1 / 2 · ( ( L · i M + 1 L 2 ) i , ( W · j N + 1 W 2 ) j , R k , ) , i = 0 , 1 , 2 N + 1 , j = 0 , 1 , 2 M + 1 ,
N i , j = 1 ( L 2 ( i M + 1 1 2 ) 2 + W 2 ( j N + 1 1 2 ) 2 + ( n R | O i , j | ) 2 ) 1 / 2 · ( ( L · i M + 1 L 2 ) i , ( W · j N + 1 W 2 ) j , ( n R | O i , j | ) k , ) , i = 0 , 1 , 2 , , N + 1 , j = 0 , 1 , 2 , , M + 1.

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