Abstract

A conformal phosphor coating can realize a phosphor layer with uniform thickness, which could enhance the angular color uniformity (ACU) of light-emitting diode (LED) packaging. In this study, a novel freeform lens was designed for simultaneous realization of LED uniform illumination and conformal phosphor coating. The detailed algorithm of the design method, which involves an extended light source and double refractions, was presented. The packaging configuration of the LED modules and the modeling of the light-conversion process were also presented. Monte Carlo ray-tracing simulations were conducted to validate the design method by comparisons with a conventional freeform lens. It is demonstrated that for the LED module with the present freeform lens, the illumination uniformity and ACU was 0.89 and 0.9283, respectively. The present freeform lens can realize equivalent illumination uniformity, but the angular color uniformity can be enhanced by 282.3% when compared with the conventional freeform lens.

© 2012 OSA

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2012

R. Hu, X. B. Luo, H. Feng, and S. Liu, “Effect of phosphor settling on the optical performance of phosphor-converted white light-emitting diodes,” J. Lumin.132(5), 1252–1256 (2012).

H. Zheng, X. B. Luo, R. Hu, B. Cao, X. Fu, Y. M. Wang, and S. Liu, “Conformal phosphor coating using capillary microchannel for controlling color deviation of phosphor-converted white light-emitting diodes,” Opt. Express20(5), 5092–5098 (2012).

2011

2010

2009

S. Pimputkar, J. S. Speck, S. P. Denbaars, and S. Nakamura, “Prospects for LED lighting,” Nat. Photonics3(4), 180–182 (2009).

S. Tonzani, “Lighting technology: Time to change the bulb,” Nature459(7245), 312–314 (2009).

Z. Y. Liu, S. Liu, K. Wang, and X. B. Luo, “Status and prospects for phosphor-based white LED packaging,” Front. Optoelectron. China2, 119–140 (2009).

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).

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).

C. Sommer, P. Hartmann, P. Pachler, M. Schweighart, S. Tasch, G. Leising, and F. P. Wenzl, “A detailed study on the requirements for angular homogeneity of phosphor converted high power white LED light sources,” Opt. Mater.31(6), 837–848 (2009).

2008

C. Sommer, F. P. Wenzl, P. Hartmann, P. Pachler, M. Schweighart, S. Tasch, and G. Leising, “Tailoring of the color conversion elements in phosphor-converted high-power LEDs by optical simulations,” IEEE Photon. Technol. Lett.20(9), 739–741 (2008).

Z. Y. Liu, S. Liu, K. Wang, and X. B. Luo, “Optical analysis of color distribution in white LEDs with various packaging methods,” IEEE Photon. Technol. Lett.20(24), 2027–2029 (2008).

Y. Ding, X. Liu, Z. R. Zheng, and P. F. Gu, “Freeform LED lens for uniform illumination,” Opt. Express16(17), 12958–12966 (2008).

2007

B. Braune, K. Petersen, J. Strauss, P. Kromotis, and M. Kaempf, “A new wafer level coating technique to reduce the color distribution of LEDs,” Proc. SPIE6486, 64860X (2007).

L. Wang, K. Qian, and Y. Luo, “Discontinuous free-form lens design for prescribed irradiance,” Appl. Opt.46(18), 3716–3723 (2007).

B. Hou, H. B. Rao, and J. F. Li, “Phosphor coating technique with slurry method in application of white LED,” Proc. SPIE6841, 684106 (2007).

2005

E. F. Schubert and J. K. Kim, “Solid-state light sources getting smart,” Science308(5726), 1274–1278 (2005).

2004

P. Benítez, J. C. Miñano, J. Blen, R. Mohedano, J. Chaves, O. Dross, M. Hernández, and W. Falicoff, “Simultaneous multiple surface optical design method in three dimensions,” Opt. Eng.43(7), 1489–1502 (2004).

2001

H. Ries and J. Muschaweck, “Tailoring freeform lenses for illumination,” Proc. SPIE4442, 43–50 (2001).

J. H. Yum, S. Y. Seo, S. Lee, and Y. E. Sung, “Comparison of Y3Al4O12:Ce0.05 phosphor coating methods for white light-emitting diode on gallium nitride,” Proc. SPIE4445, 60–69 (2001).

Benítez, P.

J. C. Miñano, P. Benítez, J. Y. Liu, J. Infante, J. Chaves, and W. Lin, “Applications of the SMS method to design of compact optics,” Proc. SPIE7717, 771701 (2010).

P. Benítez, J. C. Miñano, J. Blen, R. Mohedano, J. Chaves, O. Dross, M. Hernández, and W. Falicoff, “Simultaneous multiple surface optical design method in three dimensions,” Opt. Eng.43(7), 1489–1502 (2004).

Blen, J.

P. Benítez, J. C. Miñano, J. Blen, R. Mohedano, J. Chaves, O. Dross, M. Hernández, and W. Falicoff, “Simultaneous multiple surface optical design method in three dimensions,” Opt. Eng.43(7), 1489–1502 (2004).

Braune, B.

B. Braune, K. Petersen, J. Strauss, P. Kromotis, and M. Kaempf, “A new wafer level coating technique to reduce the color distribution of LEDs,” Proc. SPIE6486, 64860X (2007).

Cao, B.

Chaves, J.

J. C. Miñano, P. Benítez, J. Y. Liu, J. Infante, J. Chaves, and W. Lin, “Applications of the SMS method to design of compact optics,” Proc. SPIE7717, 771701 (2010).

P. Benítez, J. C. Miñano, J. Blen, R. Mohedano, J. Chaves, O. Dross, M. Hernández, and W. Falicoff, “Simultaneous multiple surface optical design method in three dimensions,” Opt. Eng.43(7), 1489–1502 (2004).

Chen, F.

Denbaars, S. P.

S. Pimputkar, J. S. Speck, S. P. Denbaars, and S. Nakamura, “Prospects for LED lighting,” Nat. Photonics3(4), 180–182 (2009).

Ding, Y.

Dross, O.

P. Benítez, J. C. Miñano, J. Blen, R. Mohedano, J. Chaves, O. Dross, M. Hernández, and W. Falicoff, “Simultaneous multiple surface optical design method in three dimensions,” Opt. Eng.43(7), 1489–1502 (2004).

Falicoff, W.

P. Benítez, J. C. Miñano, J. Blen, R. Mohedano, J. Chaves, O. Dross, M. Hernández, and W. Falicoff, “Simultaneous multiple surface optical design method in three dimensions,” Opt. Eng.43(7), 1489–1502 (2004).

Feng, H.

R. Hu, X. B. Luo, H. Feng, and S. Liu, “Effect of phosphor settling on the optical performance of phosphor-converted white light-emitting diodes,” J. Lumin.132(5), 1252–1256 (2012).

Fu, X.

Gu, P. F.

Hartmann, P.

C. Sommer, F. Reil, J. R. Krenn, P. Hartmann, P. Pachler, H. Hoschopf, and F. P. Wenzl, “The impact of light scattering on the radiant flux of phosphor-converted high power white light-emitting diodes,” J. Lightwave Technol.29(15), 2285–2291 (2011).

C. Sommer, P. Hartmann, P. Pachler, M. Schweighart, S. Tasch, G. Leising, and F. P. Wenzl, “A detailed study on the requirements for angular homogeneity of phosphor converted high power white LED light sources,” Opt. Mater.31(6), 837–848 (2009).

C. Sommer, F. P. Wenzl, P. Hartmann, P. Pachler, M. Schweighart, S. Tasch, and G. Leising, “Tailoring of the color conversion elements in phosphor-converted high-power LEDs by optical simulations,” IEEE Photon. Technol. Lett.20(9), 739–741 (2008).

Hernández, M.

P. Benítez, J. C. Miñano, J. Blen, R. Mohedano, J. Chaves, O. Dross, M. Hernández, and W. Falicoff, “Simultaneous multiple surface optical design method in three dimensions,” Opt. Eng.43(7), 1489–1502 (2004).

Hoschopf, H.

Hou, B.

B. Hou, H. B. Rao, and J. F. Li, “Phosphor coating technique with slurry method in application of white LED,” Proc. SPIE6841, 684106 (2007).

Hu, R.

R. Hu, X. B. Luo, H. Feng, and S. Liu, “Effect of phosphor settling on the optical performance of phosphor-converted white light-emitting diodes,” J. Lumin.132(5), 1252–1256 (2012).

H. Zheng, X. B. Luo, R. Hu, B. Cao, X. Fu, Y. M. Wang, and S. Liu, “Conformal phosphor coating using capillary microchannel for controlling color deviation of phosphor-converted white light-emitting diodes,” Opt. Express20(5), 5092–5098 (2012).

R. Hu, X. B. Luo, and S. Liu, “Study on the optical properties of conformal coating light-emitting diode by Monte Carlo simulation,” IEEE Photon. Technol. Lett.23(22), 1673–1675 (2011).

Infante, J.

J. C. Miñano, P. Benítez, J. Y. Liu, J. Infante, J. Chaves, and W. Lin, “Applications of the SMS method to design of compact optics,” Proc. SPIE7717, 771701 (2010).

Kaempf, M.

B. Braune, K. Petersen, J. Strauss, P. Kromotis, and M. Kaempf, “A new wafer level coating technique to reduce the color distribution of LEDs,” Proc. SPIE6486, 64860X (2007).

Kim, J. K.

E. F. Schubert and J. K. Kim, “Solid-state light sources getting smart,” Science308(5726), 1274–1278 (2005).

Krenn, J. R.

Kromotis, P.

B. Braune, K. Petersen, J. Strauss, P. Kromotis, and M. Kaempf, “A new wafer level coating technique to reduce the color distribution of LEDs,” Proc. SPIE6486, 64860X (2007).

Lee, S.

J. H. Yum, S. Y. Seo, S. Lee, and Y. E. Sung, “Comparison of Y3Al4O12:Ce0.05 phosphor coating methods for white light-emitting diode on gallium nitride,” Proc. SPIE4445, 60–69 (2001).

Leising, G.

C. Sommer, P. Hartmann, P. Pachler, M. Schweighart, S. Tasch, G. Leising, and F. P. Wenzl, “A detailed study on the requirements for angular homogeneity of phosphor converted high power white LED light sources,” Opt. Mater.31(6), 837–848 (2009).

C. Sommer, F. P. Wenzl, P. Hartmann, P. Pachler, M. Schweighart, S. Tasch, and G. Leising, “Tailoring of the color conversion elements in phosphor-converted high-power LEDs by optical simulations,” IEEE Photon. Technol. Lett.20(9), 739–741 (2008).

Li, J. F.

B. Hou, H. B. Rao, and J. F. Li, “Phosphor coating technique with slurry method in application of white LED,” Proc. SPIE6841, 684106 (2007).

Lin, W.

J. C. Miñano, P. Benítez, J. Y. Liu, J. Infante, J. Chaves, and W. Lin, “Applications of the SMS method to design of compact optics,” Proc. SPIE7717, 771701 (2010).

Liu, J. Y.

J. C. Miñano, P. Benítez, J. Y. Liu, J. Infante, J. Chaves, and W. Lin, “Applications of the SMS method to design of compact optics,” Proc. SPIE7717, 771701 (2010).

Liu, S.

R. Hu, X. B. Luo, H. Feng, and S. Liu, “Effect of phosphor settling on the optical performance of phosphor-converted white light-emitting diodes,” J. Lumin.132(5), 1252–1256 (2012).

H. Zheng, X. B. Luo, R. Hu, B. Cao, X. Fu, Y. M. Wang, and S. Liu, “Conformal phosphor coating using capillary microchannel for controlling color deviation of phosphor-converted white light-emitting diodes,” Opt. Express20(5), 5092–5098 (2012).

K. Wang, D. Wu, Z. Qin, F. Chen, X. B. Luo, and S. Liu, “New reversing design method for LED uniform illumination,” Opt. Express19(Suppl 4), A830–A840 (2011).

S. Wang, K. Wang, F. Chen, and S. Liu, “Design of primary optics for LED chip array in road lighting application,” Opt. Express19(Suppl 4), A716–A724 (2011).

R. Hu, X. B. Luo, and S. Liu, “Study on the optical properties of conformal coating light-emitting diode by Monte Carlo simulation,” IEEE Photon. Technol. Lett.23(22), 1673–1675 (2011).

F. Chen, K. Wang, Z. Qin, D. Wu, X. B. Luo, and S. Liu, “Design method of high-efficient LED headlamp lens,” Opt. Express18(20), 20926–20938 (2010).

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. Express18(2), 413–425 (2010).

Z. Y. Liu, S. Liu, K. Wang, and X. B. Luo, “Measurement and numerical studies of optical properties of YAG:Ce phosphor for white light-emitting diode packaging,” Appl. Opt.49(2), 247–257 (2010).

Z. Qin, K. Wang, F. Chen, X. B. Luo, and S. Liu, “Analysis of condition for uniform lighting generated by array of light emitting diodes with large view angle,” Opt. Express18(16), 17460–17476 (2010).

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).

Z. Y. Liu, K. Wang, X. B. Luo, and S. Liu, “Precise optical modeling of blue light-emitting diodes by Monte Carlo ray-tracing,” Opt. Express18(9), 9398–9412 (2010).

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).

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).

Z. Y. Liu, S. Liu, K. Wang, and X. B. Luo, “Status and prospects for phosphor-based white LED packaging,” Front. Optoelectron. China2, 119–140 (2009).

Z. Y. Liu, S. Liu, K. Wang, and X. B. Luo, “Optical analysis of color distribution in white LEDs with various packaging methods,” IEEE Photon. Technol. Lett.20(24), 2027–2029 (2008).

Liu, X.

Liu, Z. Y.

Z. Y. Liu, S. Liu, K. Wang, and X. B. Luo, “Measurement and numerical studies of optical properties of YAG:Ce phosphor for white light-emitting diode packaging,” Appl. Opt.49(2), 247–257 (2010).

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. Express18(2), 413–425 (2010).

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).

Z. Y. Liu, K. Wang, X. B. Luo, and S. Liu, “Precise optical modeling of blue light-emitting diodes by Monte Carlo ray-tracing,” Opt. Express18(9), 9398–9412 (2010).

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).

Z. Y. Liu, S. Liu, K. Wang, and X. B. Luo, “Status and prospects for phosphor-based white LED packaging,” Front. Optoelectron. China2, 119–140 (2009).

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).

Z. Y. Liu, S. Liu, K. Wang, and X. B. Luo, “Optical analysis of color distribution in white LEDs with various packaging methods,” IEEE Photon. Technol. Lett.20(24), 2027–2029 (2008).

Luo, X. B.

R. Hu, X. B. Luo, H. Feng, and S. Liu, “Effect of phosphor settling on the optical performance of phosphor-converted white light-emitting diodes,” J. Lumin.132(5), 1252–1256 (2012).

H. Zheng, X. B. Luo, R. Hu, B. Cao, X. Fu, Y. M. Wang, and S. Liu, “Conformal phosphor coating using capillary microchannel for controlling color deviation of phosphor-converted white light-emitting diodes,” Opt. Express20(5), 5092–5098 (2012).

K. Wang, D. Wu, Z. Qin, F. Chen, X. B. Luo, and S. Liu, “New reversing design method for LED uniform illumination,” Opt. Express19(Suppl 4), A830–A840 (2011).

R. Hu, X. B. Luo, and S. Liu, “Study on the optical properties of conformal coating light-emitting diode by Monte Carlo simulation,” IEEE Photon. Technol. Lett.23(22), 1673–1675 (2011).

F. Chen, K. Wang, Z. Qin, D. Wu, X. B. Luo, and S. Liu, “Design method of high-efficient LED headlamp lens,” Opt. Express18(20), 20926–20938 (2010).

Z. Y. Liu, S. Liu, K. Wang, and X. B. Luo, “Measurement and numerical studies of optical properties of YAG:Ce phosphor for white light-emitting diode packaging,” Appl. Opt.49(2), 247–257 (2010).

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).

Z. Qin, K. Wang, F. Chen, X. B. Luo, and S. Liu, “Analysis of condition for uniform lighting generated by array of light emitting diodes with large view angle,” Opt. Express18(16), 17460–17476 (2010).

Z. Y. Liu, K. Wang, X. B. Luo, and S. Liu, “Precise optical modeling of blue light-emitting diodes by Monte Carlo ray-tracing,” Opt. Express18(9), 9398–9412 (2010).

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. Express18(2), 413–425 (2010).

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).

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).

Z. Y. Liu, S. Liu, K. Wang, and X. B. Luo, “Status and prospects for phosphor-based white LED packaging,” Front. Optoelectron. China2, 119–140 (2009).

Z. Y. Liu, S. Liu, K. Wang, and X. B. Luo, “Optical analysis of color distribution in white LEDs with various packaging methods,” IEEE Photon. Technol. Lett.20(24), 2027–2029 (2008).

Luo, Y.

Miñano, J. C.

J. C. Miñano, P. Benítez, J. Y. Liu, J. Infante, J. Chaves, and W. Lin, “Applications of the SMS method to design of compact optics,” Proc. SPIE7717, 771701 (2010).

P. Benítez, J. C. Miñano, J. Blen, R. Mohedano, J. Chaves, O. Dross, M. Hernández, and W. Falicoff, “Simultaneous multiple surface optical design method in three dimensions,” Opt. Eng.43(7), 1489–1502 (2004).

Mohedano, R.

P. Benítez, J. C. Miñano, J. Blen, R. Mohedano, J. Chaves, O. Dross, M. Hernández, and W. Falicoff, “Simultaneous multiple surface optical design method in three dimensions,” Opt. Eng.43(7), 1489–1502 (2004).

Muschaweck, J.

H. Ries and J. Muschaweck, “Tailoring freeform lenses for illumination,” Proc. SPIE4442, 43–50 (2001).

Nakamura, S.

S. Pimputkar, J. S. Speck, S. P. Denbaars, and S. Nakamura, “Prospects for LED lighting,” Nat. Photonics3(4), 180–182 (2009).

Narendran, N.

N. Narendran, “Is solid-state lighting ready for the incandescent lamp phase-out?” Proc. SPIE8123, 812302 (2011).

Pachler, P.

C. Sommer, F. Reil, J. R. Krenn, P. Hartmann, P. Pachler, H. Hoschopf, and F. P. Wenzl, “The impact of light scattering on the radiant flux of phosphor-converted high power white light-emitting diodes,” J. Lightwave Technol.29(15), 2285–2291 (2011).

C. Sommer, P. Hartmann, P. Pachler, M. Schweighart, S. Tasch, G. Leising, and F. P. Wenzl, “A detailed study on the requirements for angular homogeneity of phosphor converted high power white LED light sources,” Opt. Mater.31(6), 837–848 (2009).

C. Sommer, F. P. Wenzl, P. Hartmann, P. Pachler, M. Schweighart, S. Tasch, and G. Leising, “Tailoring of the color conversion elements in phosphor-converted high-power LEDs by optical simulations,” IEEE Photon. Technol. Lett.20(9), 739–741 (2008).

Petersen, K.

B. Braune, K. Petersen, J. Strauss, P. Kromotis, and M. Kaempf, “A new wafer level coating technique to reduce the color distribution of LEDs,” Proc. SPIE6486, 64860X (2007).

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S. Pimputkar, J. S. Speck, S. P. Denbaars, and S. Nakamura, “Prospects for LED lighting,” Nat. Photonics3(4), 180–182 (2009).

Qian, K.

Qin, Z.

Rao, H. B.

B. Hou, H. B. Rao, and J. F. Li, “Phosphor coating technique with slurry method in application of white LED,” Proc. SPIE6841, 684106 (2007).

Reil, F.

Ries, H.

H. Ries and J. Muschaweck, “Tailoring freeform lenses for illumination,” Proc. SPIE4442, 43–50 (2001).

Schubert, E. F.

E. F. Schubert and J. K. Kim, “Solid-state light sources getting smart,” Science308(5726), 1274–1278 (2005).

Schweighart, M.

C. Sommer, P. Hartmann, P. Pachler, M. Schweighart, S. Tasch, G. Leising, and F. P. Wenzl, “A detailed study on the requirements for angular homogeneity of phosphor converted high power white LED light sources,” Opt. Mater.31(6), 837–848 (2009).

C. Sommer, F. P. Wenzl, P. Hartmann, P. Pachler, M. Schweighart, S. Tasch, and G. Leising, “Tailoring of the color conversion elements in phosphor-converted high-power LEDs by optical simulations,” IEEE Photon. Technol. Lett.20(9), 739–741 (2008).

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J. H. Yum, S. Y. Seo, S. Lee, and Y. E. Sung, “Comparison of Y3Al4O12:Ce0.05 phosphor coating methods for white light-emitting diode on gallium nitride,” Proc. SPIE4445, 60–69 (2001).

Sommer, C.

C. Sommer, F. Reil, J. R. Krenn, P. Hartmann, P. Pachler, H. Hoschopf, and F. P. Wenzl, “The impact of light scattering on the radiant flux of phosphor-converted high power white light-emitting diodes,” J. Lightwave Technol.29(15), 2285–2291 (2011).

C. Sommer, P. Hartmann, P. Pachler, M. Schweighart, S. Tasch, G. Leising, and F. P. Wenzl, “A detailed study on the requirements for angular homogeneity of phosphor converted high power white LED light sources,” Opt. Mater.31(6), 837–848 (2009).

C. Sommer, F. P. Wenzl, P. Hartmann, P. Pachler, M. Schweighart, S. Tasch, and G. Leising, “Tailoring of the color conversion elements in phosphor-converted high-power LEDs by optical simulations,” IEEE Photon. Technol. Lett.20(9), 739–741 (2008).

Speck, J. S.

S. Pimputkar, J. S. Speck, S. P. Denbaars, and S. Nakamura, “Prospects for LED lighting,” Nat. Photonics3(4), 180–182 (2009).

Strauss, J.

B. Braune, K. Petersen, J. Strauss, P. Kromotis, and M. Kaempf, “A new wafer level coating technique to reduce the color distribution of LEDs,” Proc. SPIE6486, 64860X (2007).

Sung, Y. E.

J. H. Yum, S. Y. Seo, S. Lee, and Y. E. Sung, “Comparison of Y3Al4O12:Ce0.05 phosphor coating methods for white light-emitting diode on gallium nitride,” Proc. SPIE4445, 60–69 (2001).

Tasch, S.

C. Sommer, P. Hartmann, P. Pachler, M. Schweighart, S. Tasch, G. Leising, and F. P. Wenzl, “A detailed study on the requirements for angular homogeneity of phosphor converted high power white LED light sources,” Opt. Mater.31(6), 837–848 (2009).

C. Sommer, F. P. Wenzl, P. Hartmann, P. Pachler, M. Schweighart, S. Tasch, and G. Leising, “Tailoring of the color conversion elements in phosphor-converted high-power LEDs by optical simulations,” IEEE Photon. Technol. Lett.20(9), 739–741 (2008).

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S. Tonzani, “Lighting technology: Time to change the bulb,” Nature459(7245), 312–314 (2009).

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S. Wang, K. Wang, F. Chen, and S. Liu, “Design of primary optics for LED chip array in road lighting application,” Opt. Express19(Suppl 4), A716–A724 (2011).

K. Wang, D. Wu, Z. Qin, F. Chen, X. B. Luo, and S. Liu, “New reversing design method for LED uniform illumination,” Opt. Express19(Suppl 4), A830–A840 (2011).

Z. Qin, K. Wang, F. Chen, X. B. Luo, and S. Liu, “Analysis of condition for uniform lighting generated by array of light emitting diodes with large view angle,” Opt. Express18(16), 17460–17476 (2010).

F. Chen, K. Wang, Z. Qin, D. Wu, X. B. Luo, and S. Liu, “Design method of high-efficient LED headlamp lens,” Opt. Express18(20), 20926–20938 (2010).

Z. Y. Liu, K. Wang, X. B. Luo, and S. Liu, “Precise optical modeling of blue light-emitting diodes by Monte Carlo ray-tracing,” Opt. Express18(9), 9398–9412 (2010).

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).

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. Express18(2), 413–425 (2010).

Z. Y. Liu, S. Liu, K. Wang, and X. B. Luo, “Measurement and numerical studies of optical properties of YAG:Ce phosphor for white light-emitting diode packaging,” Appl. Opt.49(2), 247–257 (2010).

Z. Y. Liu, S. Liu, K. Wang, and X. B. Luo, “Status and prospects for phosphor-based white LED packaging,” Front. Optoelectron. China2, 119–140 (2009).

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).

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).

Z. Y. Liu, S. Liu, K. Wang, and X. B. Luo, “Optical analysis of color distribution in white LEDs with various packaging methods,” IEEE Photon. Technol. Lett.20(24), 2027–2029 (2008).

Wang, L.

Wang, S.

Wang, Y. M.

Wenzl, F. P.

C. Sommer, F. Reil, J. R. Krenn, P. Hartmann, P. Pachler, H. Hoschopf, and F. P. Wenzl, “The impact of light scattering on the radiant flux of phosphor-converted high power white light-emitting diodes,” J. Lightwave Technol.29(15), 2285–2291 (2011).

C. Sommer, P. Hartmann, P. Pachler, M. Schweighart, S. Tasch, G. Leising, and F. P. Wenzl, “A detailed study on the requirements for angular homogeneity of phosphor converted high power white LED light sources,” Opt. Mater.31(6), 837–848 (2009).

C. Sommer, F. P. Wenzl, P. Hartmann, P. Pachler, M. Schweighart, S. Tasch, and G. Leising, “Tailoring of the color conversion elements in phosphor-converted high-power LEDs by optical simulations,” IEEE Photon. Technol. Lett.20(9), 739–741 (2008).

Wu, D.

Yum, J. H.

J. H. Yum, S. Y. Seo, S. Lee, and Y. E. Sung, “Comparison of Y3Al4O12:Ce0.05 phosphor coating methods for white light-emitting diode on gallium nitride,” Proc. SPIE4445, 60–69 (2001).

Zheng, H.

Zheng, Z. R.

Appl. Opt.

Front. Optoelectron. China

Z. Y. Liu, S. Liu, K. Wang, and X. B. Luo, “Status and prospects for phosphor-based white LED packaging,” Front. Optoelectron. China2, 119–140 (2009).

IEEE Photon. Technol. Lett.

R. Hu, X. B. Luo, and S. Liu, “Study on the optical properties of conformal coating light-emitting diode by Monte Carlo simulation,” IEEE Photon. Technol. Lett.23(22), 1673–1675 (2011).

C. Sommer, F. P. Wenzl, P. Hartmann, P. Pachler, M. Schweighart, S. Tasch, and G. Leising, “Tailoring of the color conversion elements in phosphor-converted high-power LEDs by optical simulations,” IEEE Photon. Technol. Lett.20(9), 739–741 (2008).

Z. Y. Liu, S. Liu, K. Wang, and X. B. Luo, “Optical analysis of color distribution in white LEDs with various packaging methods,” IEEE Photon. Technol. Lett.20(24), 2027–2029 (2008).

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J. Opt. A, Pure Appl. Opt.

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).

Nat. Photonics

S. Pimputkar, J. S. Speck, S. P. Denbaars, and S. Nakamura, “Prospects for LED lighting,” Nat. Photonics3(4), 180–182 (2009).

Nature

S. Tonzani, “Lighting technology: Time to change the bulb,” Nature459(7245), 312–314 (2009).

Opt. Eng.

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).

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Opt. Express

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C. Sommer, P. Hartmann, P. Pachler, M. Schweighart, S. Tasch, G. Leising, and F. P. Wenzl, “A detailed study on the requirements for angular homogeneity of phosphor converted high power white LED light sources,” Opt. Mater.31(6), 837–848 (2009).

Proc. SPIE

N. Narendran, “Is solid-state lighting ready for the incandescent lamp phase-out?” Proc. SPIE8123, 812302 (2011).

J. C. Miñano, P. Benítez, J. Y. Liu, J. Infante, J. Chaves, and W. Lin, “Applications of the SMS method to design of compact optics,” Proc. SPIE7717, 771701 (2010).

H. Ries and J. Muschaweck, “Tailoring freeform lenses for illumination,” Proc. SPIE4442, 43–50 (2001).

B. Hou, H. B. Rao, and J. F. Li, “Phosphor coating technique with slurry method in application of white LED,” Proc. SPIE6841, 684106 (2007).

J. H. Yum, S. Y. Seo, S. Lee, and Y. E. Sung, “Comparison of Y3Al4O12:Ce0.05 phosphor coating methods for white light-emitting diode on gallium nitride,” Proc. SPIE4445, 60–69 (2001).

B. Braune, K. Petersen, J. Strauss, P. Kromotis, and M. Kaempf, “A new wafer level coating technique to reduce the color distribution of LEDs,” Proc. SPIE6486, 64860X (2007).

Science

E. F. Schubert and J. K. Kim, “Solid-state light sources getting smart,” Science308(5726), 1274–1278 (2005).

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Figures (9)

Fig. 1
Fig. 1

(a) LED packaging module with conventional freeform lens, and (b) LED packaging module with novel freeform lens applied to conformal phosphor coating.

Fig. 2
Fig. 2

Schematic of light–energy mapping between the light source and the target plane.

Fig. 3
Fig. 3

Schematic of typical light path from the light source to the target plane through the present freeform lens. The inner surface is a cylinder and the outer surface is freeform.

Fig. 4
Fig. 4

Specific light paths from the light source to the target plane through the present freeform lens. Phosphor silicone matrix is filled in the interspace between the light source and inner surface of the lens. Blue lines are the typical light paths. Red dashed lines are the normal plane and green dashed lines are the tangent plane. Point AT is the turning point of the inner surface. αx(x = i,j) and βx(x = i,j) are the incident angle and refraction angle on the inner surface, respectively. ψx(x = i,j) and ωx(x = i,j) are the incident angle and refraction angle on the outer surface, respectively.

Fig. 5
Fig. 5

Schematic of point generation on the outer surface of the present freeform lens. Red dashed lines are the normal plane and green boxes are the tangent plane of the points on the outer surface.

Fig. 6
Fig. 6

(a) Packaging configuration of LED module with present freeform lens. (b)Structure of conventional GaN LED chip.

Fig. 7
Fig. 7

Lighting performance of the present freeform lens.

Fig. 8
Fig. 8

Lighting performance of the conventional freeform lens.

Fig. 9
Fig. 9

Comparison of light intensity of YBR and ACU in the whole radiation angle between the LED modules with the present freeform lens and the conventional freeform lens.

Equations (9)

Equations on this page are rendered with MathJax. Learn more.

Φ(θ)= 0 2π θ i θ i+1 I(θ,φ)sinθdθdφ ,
Φ total = 0 π 2 Φ(θ)dθ ,
0 θ i 2πI(θ)sinθdθ=i Φ total M ,(i=1,2,,M).
π r i 2 =i C i π L 2 M ,(i=1,2,,M).
r i =L i C i M .
n 1 OA | OA | × N 1 = n 2 AB | AB | × N 1 ,
n 2 AB | AB | × N 2 = n 3 BR | BR | × N 2 ,
n 1 sin α x = n 2 sin β x ,( x=i,j ),
n 2 sin ψ x = n 3 sin ω x ,(x=i,j).

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