Abstract

Phosphor-free dispensing is the most widely used LED packaging method, but this method results in poor quality in angular CCT uniformity. This study proposes a diffuser-loaded encapsulation to solve the problem; the effects of melamine formaldehyde (MF) resin and CaCO3 loaded encapsulation on correlated color temperature (CCT) uniformity and luminous efficiency reduction of the phosphor-converted LEDs are investigated. Results reveal that MF resin loaded encapsulation has better light diffusion performance compared to MF resin loaded encapsulation at the same diffuser concentration, but CaCO3 loaded encapsulation has better luminous efficiency maintenance. The improvements in angular color uniformity for the LEDs emitting with MF resin and CaCO3 loaded encapsulation can be explained by the increase in photon scattering. The utility of this low cost and controllable mineral diffuser packaging method provides a practical approach for enhancing the angular color uniformity of LEDs. The diffuser mass ratio of 1% MF resin or 10% CaCO3 is the optimum condition to obtain low angular CCT variance and high luminous efficiency.

© 2013 Optical Society of America

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  1. Y. K. Ee, P. Kumnorkaew, H. Tong, R. A. Arif, J. F. Gilchrist, and N. Tansu, “Enhancement of light extraction efficiency of InGaN quantum wells light-emitting diodes with polydimethylsiloxane concave microstructures,” Proc. SPIE 7231, 72310U (2009).
    [CrossRef]
  2. M. R. Krames, M. O. Holcomb, G. E. Hofler, C. C. Coman, E. I. Chen, I. H. Tan, P. Grillot, N. F. Gardner, H. C. Chui, J. W. Huang, S. A. Stockman, F. A. Kish, M. G. Craford, T. S. Tan, C. P. Kocot, M. Hueschen, J. Posselt, B. Loh, G. Sasser, and D. Collins, “High-power truncated-inverted-pyramid (AlxGa1−x)0.5In0.5P/GaP light emitting diodes exhibiting >50% external quantum efficiency,” Appl. Phys. Lett. 75, 2365–2368 (1999).
    [CrossRef]
  3. B. V. Ginneken, M. Stavridi, and J. J. Koenderink, “Diffuse and specular reflectance from rough surfaces,” Appl. Opt. 37, 130–139 (1998).
    [CrossRef]
  4. T. Fujii, Y. Gao, R. Sharma, E. L. Hu, S. P. DenBaars, and S. Nakamura, “Increase in the extraction efficiency of GaN-based light-emitting diodes via surface roughening,” Appl. Phys. Lett. 84, 855–858 (2004).
    [CrossRef]
  5. Y. Xi, X. Li, J. K. Kim, F. Mont, Th. Gessmann, H. Luo, and E. F. Schubert, “Quantitative assessment of diffusivity and specularity of surface textured reflectors for light extraction in light emitting diodes,” J. Vac. Sci. Technol. A 24, 1627–1631 (2006).
    [CrossRef]
  6. K. C. Lee, S. M. Kim, and J. H. Moon, “The effects of titania diffuser on angular color homogeneity in the phosphor conformal coated white LEDs,” Proc. SPIE 7784, 778410 (2010).
    [CrossRef]
  7. B. K. Lee, K. S. Goh, Y. L. Chin, and C. W. Tan, “Light emitting diode with gradient index layering,” U.S. Patent6,717,362 B1 (6April2004).
  8. U. Reeh, K. Höhn, N. Stath, G. Waitl, P. Schlotter, J. Schneider, and R. Schmidt, “Light-radiating semiconductor component with luminescence conversion element,” U.S. Patent6,576,930 B2 (10June2003).
  9. S. D. Lester, J. N. Miller, and D. B. Roitman, “High refractive index package material and light emitting device encapsulated with such material,” U.S. Patent5,777,433 (7July1998).
  10. Z. Z. Gu, A. Fujishima, and O. Sato, “Fabrication of high-quality opal films with controllable thickness,” Chem. Mater. 14, 760–765 (2002).
    [CrossRef]
  11. E. F. Schubert, Light Emitting Diodes (Cambridge University, 2006).
  12. 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, 837–848 (2009).
    [CrossRef]
  13. M. R. Krames, J. Bhat, D. Collins, N. F. Gardner, W. Götz, C. H. Lowery, M. Ludowise, P. S. Martin, G. Mueller, R. Mueller-Mach, S. Rudaz, D. A. Steigerwald, S. A. Stockman, and J. J. Wierer, “High-power III-nitride emitters for solid-state lighting,” Phys. Status Solidi A 192, 237–245 (2002).
    [CrossRef]
  14. J. H. Yum, S. Y. Seo, S. Lee, and Y. E. Sung, “Y3Al5O12:Ce0.05 phosphor coatings on gallium nitride for white light emitting diodes,” J. Electrochem. Soc. 150, H47–H52 (2003).
    [CrossRef]
  15. B. P. Loh, N. W. Medendorp, P. Andrews, Y. Fu, M. Laughner, and R. Letoquin, “Method of uniform phosphor chip coating and LED package fabricated using method,” U.S. Patent7,943,952 (17May2011).
  16. G. O. Muller, R. B. Mueller-Mach, M. R. Krames, P. J. Schmidt, H. H. Bechtel, J. Meyer, J. de Graaf, and T. A. Kop, “Luminescent ceramic for a light emitting device,” U.S. Patent7,361,938 (22April2008).
  17. 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, 739–741 (2008).
    [CrossRef]
  18. Z. Liu, S. Liu, K. Wang, and X. Luo, “Optical analysis of color distribution in white LEDs with various packaging methods,” IEEE Photon. Technol. Lett. 20, 2027–2029 (2008).
    [CrossRef]
  19. G. Basin, A. S. Haque, C. H. Chen, R. S. West, and P. Martin, “LED with particles in encapsulant for increased light extraction and non-yellow off-state color,” U.S. Patent7,791,093 (7September2010).
  20. J. P. Kim, M. S. Jang, W. H. Kim, J. Y. Joo, J. H. Cho, D. W. Kim, and S. B. Song, “Improvement in the color uniformity of LED by microspheres generated from phase separation,” Opt. Mater. 34, 1614–1617 (2012).
    [CrossRef]
  21. H. C. Chen, K. J. Chen, C. C. Lin, C. H. Wang, H. V. Han, H. H. Tsai, H. T. Kuo, S. H. Chien, M. H. Shih, and H. C. Kuo, “Improvement in uniformity of emission by ZrO2 nano-particles for white LEDs,” Nanotechnology 23, 265201 (2012).
    [CrossRef]
  22. F. W. Mont, J. K. Kim, M. F. Schubert, E. F. Schubert, and R. W. Siegel, “High-refractive-index TiO2-nanoparticle-loaded encapsulants for light emitting diodes,” J. Appl. Phys. 103, 083120 (2008).
    [CrossRef]

2012 (2)

J. P. Kim, M. S. Jang, W. H. Kim, J. Y. Joo, J. H. Cho, D. W. Kim, and S. B. Song, “Improvement in the color uniformity of LED by microspheres generated from phase separation,” Opt. Mater. 34, 1614–1617 (2012).
[CrossRef]

H. C. Chen, K. J. Chen, C. C. Lin, C. H. Wang, H. V. Han, H. H. Tsai, H. T. Kuo, S. H. Chien, M. H. Shih, and H. C. Kuo, “Improvement in uniformity of emission by ZrO2 nano-particles for white LEDs,” Nanotechnology 23, 265201 (2012).
[CrossRef]

2010 (1)

K. C. Lee, S. M. Kim, and J. H. Moon, “The effects of titania diffuser on angular color homogeneity in the phosphor conformal coated white LEDs,” Proc. SPIE 7784, 778410 (2010).
[CrossRef]

2009 (2)

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, 837–848 (2009).
[CrossRef]

Y. K. Ee, P. Kumnorkaew, H. Tong, R. A. Arif, J. F. Gilchrist, and N. Tansu, “Enhancement of light extraction efficiency of InGaN quantum wells light-emitting diodes with polydimethylsiloxane concave microstructures,” Proc. SPIE 7231, 72310U (2009).
[CrossRef]

2008 (3)

F. W. Mont, J. K. Kim, M. F. Schubert, E. F. Schubert, and R. W. Siegel, “High-refractive-index TiO2-nanoparticle-loaded encapsulants for light emitting diodes,” J. Appl. Phys. 103, 083120 (2008).
[CrossRef]

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, 739–741 (2008).
[CrossRef]

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

2006 (1)

Y. Xi, X. Li, J. K. Kim, F. Mont, Th. Gessmann, H. Luo, and E. F. Schubert, “Quantitative assessment of diffusivity and specularity of surface textured reflectors for light extraction in light emitting diodes,” J. Vac. Sci. Technol. A 24, 1627–1631 (2006).
[CrossRef]

2004 (1)

T. Fujii, Y. Gao, R. Sharma, E. L. Hu, S. P. DenBaars, and S. Nakamura, “Increase in the extraction efficiency of GaN-based light-emitting diodes via surface roughening,” Appl. Phys. Lett. 84, 855–858 (2004).
[CrossRef]

2003 (1)

J. H. Yum, S. Y. Seo, S. Lee, and Y. E. Sung, “Y3Al5O12:Ce0.05 phosphor coatings on gallium nitride for white light emitting diodes,” J. Electrochem. Soc. 150, H47–H52 (2003).
[CrossRef]

2002 (2)

Z. Z. Gu, A. Fujishima, and O. Sato, “Fabrication of high-quality opal films with controllable thickness,” Chem. Mater. 14, 760–765 (2002).
[CrossRef]

M. R. Krames, J. Bhat, D. Collins, N. F. Gardner, W. Götz, C. H. Lowery, M. Ludowise, P. S. Martin, G. Mueller, R. Mueller-Mach, S. Rudaz, D. A. Steigerwald, S. A. Stockman, and J. J. Wierer, “High-power III-nitride emitters for solid-state lighting,” Phys. Status Solidi A 192, 237–245 (2002).
[CrossRef]

1999 (1)

M. R. Krames, M. O. Holcomb, G. E. Hofler, C. C. Coman, E. I. Chen, I. H. Tan, P. Grillot, N. F. Gardner, H. C. Chui, J. W. Huang, S. A. Stockman, F. A. Kish, M. G. Craford, T. S. Tan, C. P. Kocot, M. Hueschen, J. Posselt, B. Loh, G. Sasser, and D. Collins, “High-power truncated-inverted-pyramid (AlxGa1−x)0.5In0.5P/GaP light emitting diodes exhibiting >50% external quantum efficiency,” Appl. Phys. Lett. 75, 2365–2368 (1999).
[CrossRef]

1998 (1)

Andrews, P.

B. P. Loh, N. W. Medendorp, P. Andrews, Y. Fu, M. Laughner, and R. Letoquin, “Method of uniform phosphor chip coating and LED package fabricated using method,” U.S. Patent7,943,952 (17May2011).

Arif, R. A.

Y. K. Ee, P. Kumnorkaew, H. Tong, R. A. Arif, J. F. Gilchrist, and N. Tansu, “Enhancement of light extraction efficiency of InGaN quantum wells light-emitting diodes with polydimethylsiloxane concave microstructures,” Proc. SPIE 7231, 72310U (2009).
[CrossRef]

Basin, G.

G. Basin, A. S. Haque, C. H. Chen, R. S. West, and P. Martin, “LED with particles in encapsulant for increased light extraction and non-yellow off-state color,” U.S. Patent7,791,093 (7September2010).

Bechtel, H. H.

G. O. Muller, R. B. Mueller-Mach, M. R. Krames, P. J. Schmidt, H. H. Bechtel, J. Meyer, J. de Graaf, and T. A. Kop, “Luminescent ceramic for a light emitting device,” U.S. Patent7,361,938 (22April2008).

Bhat, J.

M. R. Krames, J. Bhat, D. Collins, N. F. Gardner, W. Götz, C. H. Lowery, M. Ludowise, P. S. Martin, G. Mueller, R. Mueller-Mach, S. Rudaz, D. A. Steigerwald, S. A. Stockman, and J. J. Wierer, “High-power III-nitride emitters for solid-state lighting,” Phys. Status Solidi A 192, 237–245 (2002).
[CrossRef]

Chen, C. H.

G. Basin, A. S. Haque, C. H. Chen, R. S. West, and P. Martin, “LED with particles in encapsulant for increased light extraction and non-yellow off-state color,” U.S. Patent7,791,093 (7September2010).

Chen, E. I.

M. R. Krames, M. O. Holcomb, G. E. Hofler, C. C. Coman, E. I. Chen, I. H. Tan, P. Grillot, N. F. Gardner, H. C. Chui, J. W. Huang, S. A. Stockman, F. A. Kish, M. G. Craford, T. S. Tan, C. P. Kocot, M. Hueschen, J. Posselt, B. Loh, G. Sasser, and D. Collins, “High-power truncated-inverted-pyramid (AlxGa1−x)0.5In0.5P/GaP light emitting diodes exhibiting >50% external quantum efficiency,” Appl. Phys. Lett. 75, 2365–2368 (1999).
[CrossRef]

Chen, H. C.

H. C. Chen, K. J. Chen, C. C. Lin, C. H. Wang, H. V. Han, H. H. Tsai, H. T. Kuo, S. H. Chien, M. H. Shih, and H. C. Kuo, “Improvement in uniformity of emission by ZrO2 nano-particles for white LEDs,” Nanotechnology 23, 265201 (2012).
[CrossRef]

Chen, K. J.

H. C. Chen, K. J. Chen, C. C. Lin, C. H. Wang, H. V. Han, H. H. Tsai, H. T. Kuo, S. H. Chien, M. H. Shih, and H. C. Kuo, “Improvement in uniformity of emission by ZrO2 nano-particles for white LEDs,” Nanotechnology 23, 265201 (2012).
[CrossRef]

Chien, S. H.

H. C. Chen, K. J. Chen, C. C. Lin, C. H. Wang, H. V. Han, H. H. Tsai, H. T. Kuo, S. H. Chien, M. H. Shih, and H. C. Kuo, “Improvement in uniformity of emission by ZrO2 nano-particles for white LEDs,” Nanotechnology 23, 265201 (2012).
[CrossRef]

Chin, Y. L.

B. K. Lee, K. S. Goh, Y. L. Chin, and C. W. Tan, “Light emitting diode with gradient index layering,” U.S. Patent6,717,362 B1 (6April2004).

Cho, J. H.

J. P. Kim, M. S. Jang, W. H. Kim, J. Y. Joo, J. H. Cho, D. W. Kim, and S. B. Song, “Improvement in the color uniformity of LED by microspheres generated from phase separation,” Opt. Mater. 34, 1614–1617 (2012).
[CrossRef]

Chui, H. C.

M. R. Krames, M. O. Holcomb, G. E. Hofler, C. C. Coman, E. I. Chen, I. H. Tan, P. Grillot, N. F. Gardner, H. C. Chui, J. W. Huang, S. A. Stockman, F. A. Kish, M. G. Craford, T. S. Tan, C. P. Kocot, M. Hueschen, J. Posselt, B. Loh, G. Sasser, and D. Collins, “High-power truncated-inverted-pyramid (AlxGa1−x)0.5In0.5P/GaP light emitting diodes exhibiting >50% external quantum efficiency,” Appl. Phys. Lett. 75, 2365–2368 (1999).
[CrossRef]

Collins, D.

M. R. Krames, J. Bhat, D. Collins, N. F. Gardner, W. Götz, C. H. Lowery, M. Ludowise, P. S. Martin, G. Mueller, R. Mueller-Mach, S. Rudaz, D. A. Steigerwald, S. A. Stockman, and J. J. Wierer, “High-power III-nitride emitters for solid-state lighting,” Phys. Status Solidi A 192, 237–245 (2002).
[CrossRef]

M. R. Krames, M. O. Holcomb, G. E. Hofler, C. C. Coman, E. I. Chen, I. H. Tan, P. Grillot, N. F. Gardner, H. C. Chui, J. W. Huang, S. A. Stockman, F. A. Kish, M. G. Craford, T. S. Tan, C. P. Kocot, M. Hueschen, J. Posselt, B. Loh, G. Sasser, and D. Collins, “High-power truncated-inverted-pyramid (AlxGa1−x)0.5In0.5P/GaP light emitting diodes exhibiting >50% external quantum efficiency,” Appl. Phys. Lett. 75, 2365–2368 (1999).
[CrossRef]

Coman, C. C.

M. R. Krames, M. O. Holcomb, G. E. Hofler, C. C. Coman, E. I. Chen, I. H. Tan, P. Grillot, N. F. Gardner, H. C. Chui, J. W. Huang, S. A. Stockman, F. A. Kish, M. G. Craford, T. S. Tan, C. P. Kocot, M. Hueschen, J. Posselt, B. Loh, G. Sasser, and D. Collins, “High-power truncated-inverted-pyramid (AlxGa1−x)0.5In0.5P/GaP light emitting diodes exhibiting >50% external quantum efficiency,” Appl. Phys. Lett. 75, 2365–2368 (1999).
[CrossRef]

Craford, M. G.

M. R. Krames, M. O. Holcomb, G. E. Hofler, C. C. Coman, E. I. Chen, I. H. Tan, P. Grillot, N. F. Gardner, H. C. Chui, J. W. Huang, S. A. Stockman, F. A. Kish, M. G. Craford, T. S. Tan, C. P. Kocot, M. Hueschen, J. Posselt, B. Loh, G. Sasser, and D. Collins, “High-power truncated-inverted-pyramid (AlxGa1−x)0.5In0.5P/GaP light emitting diodes exhibiting >50% external quantum efficiency,” Appl. Phys. Lett. 75, 2365–2368 (1999).
[CrossRef]

de Graaf, J.

G. O. Muller, R. B. Mueller-Mach, M. R. Krames, P. J. Schmidt, H. H. Bechtel, J. Meyer, J. de Graaf, and T. A. Kop, “Luminescent ceramic for a light emitting device,” U.S. Patent7,361,938 (22April2008).

DenBaars, S. P.

T. Fujii, Y. Gao, R. Sharma, E. L. Hu, S. P. DenBaars, and S. Nakamura, “Increase in the extraction efficiency of GaN-based light-emitting diodes via surface roughening,” Appl. Phys. Lett. 84, 855–858 (2004).
[CrossRef]

Ee, Y. K.

Y. K. Ee, P. Kumnorkaew, H. Tong, R. A. Arif, J. F. Gilchrist, and N. Tansu, “Enhancement of light extraction efficiency of InGaN quantum wells light-emitting diodes with polydimethylsiloxane concave microstructures,” Proc. SPIE 7231, 72310U (2009).
[CrossRef]

Fu, Y.

B. P. Loh, N. W. Medendorp, P. Andrews, Y. Fu, M. Laughner, and R. Letoquin, “Method of uniform phosphor chip coating and LED package fabricated using method,” U.S. Patent7,943,952 (17May2011).

Fujii, T.

T. Fujii, Y. Gao, R. Sharma, E. L. Hu, S. P. DenBaars, and S. Nakamura, “Increase in the extraction efficiency of GaN-based light-emitting diodes via surface roughening,” Appl. Phys. Lett. 84, 855–858 (2004).
[CrossRef]

Fujishima, A.

Z. Z. Gu, A. Fujishima, and O. Sato, “Fabrication of high-quality opal films with controllable thickness,” Chem. Mater. 14, 760–765 (2002).
[CrossRef]

Gao, Y.

T. Fujii, Y. Gao, R. Sharma, E. L. Hu, S. P. DenBaars, and S. Nakamura, “Increase in the extraction efficiency of GaN-based light-emitting diodes via surface roughening,” Appl. Phys. Lett. 84, 855–858 (2004).
[CrossRef]

Gardner, N. F.

M. R. Krames, J. Bhat, D. Collins, N. F. Gardner, W. Götz, C. H. Lowery, M. Ludowise, P. S. Martin, G. Mueller, R. Mueller-Mach, S. Rudaz, D. A. Steigerwald, S. A. Stockman, and J. J. Wierer, “High-power III-nitride emitters for solid-state lighting,” Phys. Status Solidi A 192, 237–245 (2002).
[CrossRef]

M. R. Krames, M. O. Holcomb, G. E. Hofler, C. C. Coman, E. I. Chen, I. H. Tan, P. Grillot, N. F. Gardner, H. C. Chui, J. W. Huang, S. A. Stockman, F. A. Kish, M. G. Craford, T. S. Tan, C. P. Kocot, M. Hueschen, J. Posselt, B. Loh, G. Sasser, and D. Collins, “High-power truncated-inverted-pyramid (AlxGa1−x)0.5In0.5P/GaP light emitting diodes exhibiting >50% external quantum efficiency,” Appl. Phys. Lett. 75, 2365–2368 (1999).
[CrossRef]

Gessmann, Th.

Y. Xi, X. Li, J. K. Kim, F. Mont, Th. Gessmann, H. Luo, and E. F. Schubert, “Quantitative assessment of diffusivity and specularity of surface textured reflectors for light extraction in light emitting diodes,” J. Vac. Sci. Technol. A 24, 1627–1631 (2006).
[CrossRef]

Gilchrist, J. F.

Y. K. Ee, P. Kumnorkaew, H. Tong, R. A. Arif, J. F. Gilchrist, and N. Tansu, “Enhancement of light extraction efficiency of InGaN quantum wells light-emitting diodes with polydimethylsiloxane concave microstructures,” Proc. SPIE 7231, 72310U (2009).
[CrossRef]

Ginneken, B. V.

Goh, K. S.

B. K. Lee, K. S. Goh, Y. L. Chin, and C. W. Tan, “Light emitting diode with gradient index layering,” U.S. Patent6,717,362 B1 (6April2004).

Götz, W.

M. R. Krames, J. Bhat, D. Collins, N. F. Gardner, W. Götz, C. H. Lowery, M. Ludowise, P. S. Martin, G. Mueller, R. Mueller-Mach, S. Rudaz, D. A. Steigerwald, S. A. Stockman, and J. J. Wierer, “High-power III-nitride emitters for solid-state lighting,” Phys. Status Solidi A 192, 237–245 (2002).
[CrossRef]

Grillot, P.

M. R. Krames, M. O. Holcomb, G. E. Hofler, C. C. Coman, E. I. Chen, I. H. Tan, P. Grillot, N. F. Gardner, H. C. Chui, J. W. Huang, S. A. Stockman, F. A. Kish, M. G. Craford, T. S. Tan, C. P. Kocot, M. Hueschen, J. Posselt, B. Loh, G. Sasser, and D. Collins, “High-power truncated-inverted-pyramid (AlxGa1−x)0.5In0.5P/GaP light emitting diodes exhibiting >50% external quantum efficiency,” Appl. Phys. Lett. 75, 2365–2368 (1999).
[CrossRef]

Gu, Z. Z.

Z. Z. Gu, A. Fujishima, and O. Sato, “Fabrication of high-quality opal films with controllable thickness,” Chem. Mater. 14, 760–765 (2002).
[CrossRef]

Han, H. V.

H. C. Chen, K. J. Chen, C. C. Lin, C. H. Wang, H. V. Han, H. H. Tsai, H. T. Kuo, S. H. Chien, M. H. Shih, and H. C. Kuo, “Improvement in uniformity of emission by ZrO2 nano-particles for white LEDs,” Nanotechnology 23, 265201 (2012).
[CrossRef]

Haque, A. S.

G. Basin, A. S. Haque, C. H. Chen, R. S. West, and P. Martin, “LED with particles in encapsulant for increased light extraction and non-yellow off-state color,” U.S. Patent7,791,093 (7September2010).

Hartmann, P.

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, 837–848 (2009).
[CrossRef]

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, 739–741 (2008).
[CrossRef]

Hofler, G. E.

M. R. Krames, M. O. Holcomb, G. E. Hofler, C. C. Coman, E. I. Chen, I. H. Tan, P. Grillot, N. F. Gardner, H. C. Chui, J. W. Huang, S. A. Stockman, F. A. Kish, M. G. Craford, T. S. Tan, C. P. Kocot, M. Hueschen, J. Posselt, B. Loh, G. Sasser, and D. Collins, “High-power truncated-inverted-pyramid (AlxGa1−x)0.5In0.5P/GaP light emitting diodes exhibiting >50% external quantum efficiency,” Appl. Phys. Lett. 75, 2365–2368 (1999).
[CrossRef]

Höhn, K.

U. Reeh, K. Höhn, N. Stath, G. Waitl, P. Schlotter, J. Schneider, and R. Schmidt, “Light-radiating semiconductor component with luminescence conversion element,” U.S. Patent6,576,930 B2 (10June2003).

Holcomb, M. O.

M. R. Krames, M. O. Holcomb, G. E. Hofler, C. C. Coman, E. I. Chen, I. H. Tan, P. Grillot, N. F. Gardner, H. C. Chui, J. W. Huang, S. A. Stockman, F. A. Kish, M. G. Craford, T. S. Tan, C. P. Kocot, M. Hueschen, J. Posselt, B. Loh, G. Sasser, and D. Collins, “High-power truncated-inverted-pyramid (AlxGa1−x)0.5In0.5P/GaP light emitting diodes exhibiting >50% external quantum efficiency,” Appl. Phys. Lett. 75, 2365–2368 (1999).
[CrossRef]

Hu, E. L.

T. Fujii, Y. Gao, R. Sharma, E. L. Hu, S. P. DenBaars, and S. Nakamura, “Increase in the extraction efficiency of GaN-based light-emitting diodes via surface roughening,” Appl. Phys. Lett. 84, 855–858 (2004).
[CrossRef]

Huang, J. W.

M. R. Krames, M. O. Holcomb, G. E. Hofler, C. C. Coman, E. I. Chen, I. H. Tan, P. Grillot, N. F. Gardner, H. C. Chui, J. W. Huang, S. A. Stockman, F. A. Kish, M. G. Craford, T. S. Tan, C. P. Kocot, M. Hueschen, J. Posselt, B. Loh, G. Sasser, and D. Collins, “High-power truncated-inverted-pyramid (AlxGa1−x)0.5In0.5P/GaP light emitting diodes exhibiting >50% external quantum efficiency,” Appl. Phys. Lett. 75, 2365–2368 (1999).
[CrossRef]

Hueschen, M.

M. R. Krames, M. O. Holcomb, G. E. Hofler, C. C. Coman, E. I. Chen, I. H. Tan, P. Grillot, N. F. Gardner, H. C. Chui, J. W. Huang, S. A. Stockman, F. A. Kish, M. G. Craford, T. S. Tan, C. P. Kocot, M. Hueschen, J. Posselt, B. Loh, G. Sasser, and D. Collins, “High-power truncated-inverted-pyramid (AlxGa1−x)0.5In0.5P/GaP light emitting diodes exhibiting >50% external quantum efficiency,” Appl. Phys. Lett. 75, 2365–2368 (1999).
[CrossRef]

Jang, M. S.

J. P. Kim, M. S. Jang, W. H. Kim, J. Y. Joo, J. H. Cho, D. W. Kim, and S. B. Song, “Improvement in the color uniformity of LED by microspheres generated from phase separation,” Opt. Mater. 34, 1614–1617 (2012).
[CrossRef]

Joo, J. Y.

J. P. Kim, M. S. Jang, W. H. Kim, J. Y. Joo, J. H. Cho, D. W. Kim, and S. B. Song, “Improvement in the color uniformity of LED by microspheres generated from phase separation,” Opt. Mater. 34, 1614–1617 (2012).
[CrossRef]

Kim, D. W.

J. P. Kim, M. S. Jang, W. H. Kim, J. Y. Joo, J. H. Cho, D. W. Kim, and S. B. Song, “Improvement in the color uniformity of LED by microspheres generated from phase separation,” Opt. Mater. 34, 1614–1617 (2012).
[CrossRef]

Kim, J. K.

F. W. Mont, J. K. Kim, M. F. Schubert, E. F. Schubert, and R. W. Siegel, “High-refractive-index TiO2-nanoparticle-loaded encapsulants for light emitting diodes,” J. Appl. Phys. 103, 083120 (2008).
[CrossRef]

Y. Xi, X. Li, J. K. Kim, F. Mont, Th. Gessmann, H. Luo, and E. F. Schubert, “Quantitative assessment of diffusivity and specularity of surface textured reflectors for light extraction in light emitting diodes,” J. Vac. Sci. Technol. A 24, 1627–1631 (2006).
[CrossRef]

Kim, J. P.

J. P. Kim, M. S. Jang, W. H. Kim, J. Y. Joo, J. H. Cho, D. W. Kim, and S. B. Song, “Improvement in the color uniformity of LED by microspheres generated from phase separation,” Opt. Mater. 34, 1614–1617 (2012).
[CrossRef]

Kim, S. M.

K. C. Lee, S. M. Kim, and J. H. Moon, “The effects of titania diffuser on angular color homogeneity in the phosphor conformal coated white LEDs,” Proc. SPIE 7784, 778410 (2010).
[CrossRef]

Kim, W. H.

J. P. Kim, M. S. Jang, W. H. Kim, J. Y. Joo, J. H. Cho, D. W. Kim, and S. B. Song, “Improvement in the color uniformity of LED by microspheres generated from phase separation,” Opt. Mater. 34, 1614–1617 (2012).
[CrossRef]

Kish, F. A.

M. R. Krames, M. O. Holcomb, G. E. Hofler, C. C. Coman, E. I. Chen, I. H. Tan, P. Grillot, N. F. Gardner, H. C. Chui, J. W. Huang, S. A. Stockman, F. A. Kish, M. G. Craford, T. S. Tan, C. P. Kocot, M. Hueschen, J. Posselt, B. Loh, G. Sasser, and D. Collins, “High-power truncated-inverted-pyramid (AlxGa1−x)0.5In0.5P/GaP light emitting diodes exhibiting >50% external quantum efficiency,” Appl. Phys. Lett. 75, 2365–2368 (1999).
[CrossRef]

Kocot, C. P.

M. R. Krames, M. O. Holcomb, G. E. Hofler, C. C. Coman, E. I. Chen, I. H. Tan, P. Grillot, N. F. Gardner, H. C. Chui, J. W. Huang, S. A. Stockman, F. A. Kish, M. G. Craford, T. S. Tan, C. P. Kocot, M. Hueschen, J. Posselt, B. Loh, G. Sasser, and D. Collins, “High-power truncated-inverted-pyramid (AlxGa1−x)0.5In0.5P/GaP light emitting diodes exhibiting >50% external quantum efficiency,” Appl. Phys. Lett. 75, 2365–2368 (1999).
[CrossRef]

Koenderink, J. J.

Kop, T. A.

G. O. Muller, R. B. Mueller-Mach, M. R. Krames, P. J. Schmidt, H. H. Bechtel, J. Meyer, J. de Graaf, and T. A. Kop, “Luminescent ceramic for a light emitting device,” U.S. Patent7,361,938 (22April2008).

Krames, M. R.

M. R. Krames, J. Bhat, D. Collins, N. F. Gardner, W. Götz, C. H. Lowery, M. Ludowise, P. S. Martin, G. Mueller, R. Mueller-Mach, S. Rudaz, D. A. Steigerwald, S. A. Stockman, and J. J. Wierer, “High-power III-nitride emitters for solid-state lighting,” Phys. Status Solidi A 192, 237–245 (2002).
[CrossRef]

M. R. Krames, M. O. Holcomb, G. E. Hofler, C. C. Coman, E. I. Chen, I. H. Tan, P. Grillot, N. F. Gardner, H. C. Chui, J. W. Huang, S. A. Stockman, F. A. Kish, M. G. Craford, T. S. Tan, C. P. Kocot, M. Hueschen, J. Posselt, B. Loh, G. Sasser, and D. Collins, “High-power truncated-inverted-pyramid (AlxGa1−x)0.5In0.5P/GaP light emitting diodes exhibiting >50% external quantum efficiency,” Appl. Phys. Lett. 75, 2365–2368 (1999).
[CrossRef]

G. O. Muller, R. B. Mueller-Mach, M. R. Krames, P. J. Schmidt, H. H. Bechtel, J. Meyer, J. de Graaf, and T. A. Kop, “Luminescent ceramic for a light emitting device,” U.S. Patent7,361,938 (22April2008).

Kumnorkaew, P.

Y. K. Ee, P. Kumnorkaew, H. Tong, R. A. Arif, J. F. Gilchrist, and N. Tansu, “Enhancement of light extraction efficiency of InGaN quantum wells light-emitting diodes with polydimethylsiloxane concave microstructures,” Proc. SPIE 7231, 72310U (2009).
[CrossRef]

Kuo, H. C.

H. C. Chen, K. J. Chen, C. C. Lin, C. H. Wang, H. V. Han, H. H. Tsai, H. T. Kuo, S. H. Chien, M. H. Shih, and H. C. Kuo, “Improvement in uniformity of emission by ZrO2 nano-particles for white LEDs,” Nanotechnology 23, 265201 (2012).
[CrossRef]

Kuo, H. T.

H. C. Chen, K. J. Chen, C. C. Lin, C. H. Wang, H. V. Han, H. H. Tsai, H. T. Kuo, S. H. Chien, M. H. Shih, and H. C. Kuo, “Improvement in uniformity of emission by ZrO2 nano-particles for white LEDs,” Nanotechnology 23, 265201 (2012).
[CrossRef]

Laughner, M.

B. P. Loh, N. W. Medendorp, P. Andrews, Y. Fu, M. Laughner, and R. Letoquin, “Method of uniform phosphor chip coating and LED package fabricated using method,” U.S. Patent7,943,952 (17May2011).

Lee, B. K.

B. K. Lee, K. S. Goh, Y. L. Chin, and C. W. Tan, “Light emitting diode with gradient index layering,” U.S. Patent6,717,362 B1 (6April2004).

Lee, K. C.

K. C. Lee, S. M. Kim, and J. H. Moon, “The effects of titania diffuser on angular color homogeneity in the phosphor conformal coated white LEDs,” Proc. SPIE 7784, 778410 (2010).
[CrossRef]

Lee, S.

J. H. Yum, S. Y. Seo, S. Lee, and Y. E. Sung, “Y3Al5O12:Ce0.05 phosphor coatings on gallium nitride for white light emitting diodes,” J. Electrochem. Soc. 150, H47–H52 (2003).
[CrossRef]

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, 837–848 (2009).
[CrossRef]

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, 739–741 (2008).
[CrossRef]

Lester, S. D.

S. D. Lester, J. N. Miller, and D. B. Roitman, “High refractive index package material and light emitting device encapsulated with such material,” U.S. Patent5,777,433 (7July1998).

Letoquin, R.

B. P. Loh, N. W. Medendorp, P. Andrews, Y. Fu, M. Laughner, and R. Letoquin, “Method of uniform phosphor chip coating and LED package fabricated using method,” U.S. Patent7,943,952 (17May2011).

Li, X.

Y. Xi, X. Li, J. K. Kim, F. Mont, Th. Gessmann, H. Luo, and E. F. Schubert, “Quantitative assessment of diffusivity and specularity of surface textured reflectors for light extraction in light emitting diodes,” J. Vac. Sci. Technol. A 24, 1627–1631 (2006).
[CrossRef]

Lin, C. C.

H. C. Chen, K. J. Chen, C. C. Lin, C. H. Wang, H. V. Han, H. H. Tsai, H. T. Kuo, S. H. Chien, M. H. Shih, and H. C. Kuo, “Improvement in uniformity of emission by ZrO2 nano-particles for white LEDs,” Nanotechnology 23, 265201 (2012).
[CrossRef]

Liu, S.

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

Liu, Z.

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

Loh, B.

M. R. Krames, M. O. Holcomb, G. E. Hofler, C. C. Coman, E. I. Chen, I. H. Tan, P. Grillot, N. F. Gardner, H. C. Chui, J. W. Huang, S. A. Stockman, F. A. Kish, M. G. Craford, T. S. Tan, C. P. Kocot, M. Hueschen, J. Posselt, B. Loh, G. Sasser, and D. Collins, “High-power truncated-inverted-pyramid (AlxGa1−x)0.5In0.5P/GaP light emitting diodes exhibiting >50% external quantum efficiency,” Appl. Phys. Lett. 75, 2365–2368 (1999).
[CrossRef]

Loh, B. P.

B. P. Loh, N. W. Medendorp, P. Andrews, Y. Fu, M. Laughner, and R. Letoquin, “Method of uniform phosphor chip coating and LED package fabricated using method,” U.S. Patent7,943,952 (17May2011).

Lowery, C. H.

M. R. Krames, J. Bhat, D. Collins, N. F. Gardner, W. Götz, C. H. Lowery, M. Ludowise, P. S. Martin, G. Mueller, R. Mueller-Mach, S. Rudaz, D. A. Steigerwald, S. A. Stockman, and J. J. Wierer, “High-power III-nitride emitters for solid-state lighting,” Phys. Status Solidi A 192, 237–245 (2002).
[CrossRef]

Ludowise, M.

M. R. Krames, J. Bhat, D. Collins, N. F. Gardner, W. Götz, C. H. Lowery, M. Ludowise, P. S. Martin, G. Mueller, R. Mueller-Mach, S. Rudaz, D. A. Steigerwald, S. A. Stockman, and J. J. Wierer, “High-power III-nitride emitters for solid-state lighting,” Phys. Status Solidi A 192, 237–245 (2002).
[CrossRef]

Luo, H.

Y. Xi, X. Li, J. K. Kim, F. Mont, Th. Gessmann, H. Luo, and E. F. Schubert, “Quantitative assessment of diffusivity and specularity of surface textured reflectors for light extraction in light emitting diodes,” J. Vac. Sci. Technol. A 24, 1627–1631 (2006).
[CrossRef]

Luo, X.

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

Martin, P.

G. Basin, A. S. Haque, C. H. Chen, R. S. West, and P. Martin, “LED with particles in encapsulant for increased light extraction and non-yellow off-state color,” U.S. Patent7,791,093 (7September2010).

Martin, P. S.

M. R. Krames, J. Bhat, D. Collins, N. F. Gardner, W. Götz, C. H. Lowery, M. Ludowise, P. S. Martin, G. Mueller, R. Mueller-Mach, S. Rudaz, D. A. Steigerwald, S. A. Stockman, and J. J. Wierer, “High-power III-nitride emitters for solid-state lighting,” Phys. Status Solidi A 192, 237–245 (2002).
[CrossRef]

Medendorp, N. W.

B. P. Loh, N. W. Medendorp, P. Andrews, Y. Fu, M. Laughner, and R. Letoquin, “Method of uniform phosphor chip coating and LED package fabricated using method,” U.S. Patent7,943,952 (17May2011).

Meyer, J.

G. O. Muller, R. B. Mueller-Mach, M. R. Krames, P. J. Schmidt, H. H. Bechtel, J. Meyer, J. de Graaf, and T. A. Kop, “Luminescent ceramic for a light emitting device,” U.S. Patent7,361,938 (22April2008).

Miller, J. N.

S. D. Lester, J. N. Miller, and D. B. Roitman, “High refractive index package material and light emitting device encapsulated with such material,” U.S. Patent5,777,433 (7July1998).

Mont, F.

Y. Xi, X. Li, J. K. Kim, F. Mont, Th. Gessmann, H. Luo, and E. F. Schubert, “Quantitative assessment of diffusivity and specularity of surface textured reflectors for light extraction in light emitting diodes,” J. Vac. Sci. Technol. A 24, 1627–1631 (2006).
[CrossRef]

Mont, F. W.

F. W. Mont, J. K. Kim, M. F. Schubert, E. F. Schubert, and R. W. Siegel, “High-refractive-index TiO2-nanoparticle-loaded encapsulants for light emitting diodes,” J. Appl. Phys. 103, 083120 (2008).
[CrossRef]

Moon, J. H.

K. C. Lee, S. M. Kim, and J. H. Moon, “The effects of titania diffuser on angular color homogeneity in the phosphor conformal coated white LEDs,” Proc. SPIE 7784, 778410 (2010).
[CrossRef]

Mueller, G.

M. R. Krames, J. Bhat, D. Collins, N. F. Gardner, W. Götz, C. H. Lowery, M. Ludowise, P. S. Martin, G. Mueller, R. Mueller-Mach, S. Rudaz, D. A. Steigerwald, S. A. Stockman, and J. J. Wierer, “High-power III-nitride emitters for solid-state lighting,” Phys. Status Solidi A 192, 237–245 (2002).
[CrossRef]

Mueller-Mach, R.

M. R. Krames, J. Bhat, D. Collins, N. F. Gardner, W. Götz, C. H. Lowery, M. Ludowise, P. S. Martin, G. Mueller, R. Mueller-Mach, S. Rudaz, D. A. Steigerwald, S. A. Stockman, and J. J. Wierer, “High-power III-nitride emitters for solid-state lighting,” Phys. Status Solidi A 192, 237–245 (2002).
[CrossRef]

Mueller-Mach, R. B.

G. O. Muller, R. B. Mueller-Mach, M. R. Krames, P. J. Schmidt, H. H. Bechtel, J. Meyer, J. de Graaf, and T. A. Kop, “Luminescent ceramic for a light emitting device,” U.S. Patent7,361,938 (22April2008).

Muller, G. O.

G. O. Muller, R. B. Mueller-Mach, M. R. Krames, P. J. Schmidt, H. H. Bechtel, J. Meyer, J. de Graaf, and T. A. Kop, “Luminescent ceramic for a light emitting device,” U.S. Patent7,361,938 (22April2008).

Nakamura, S.

T. Fujii, Y. Gao, R. Sharma, E. L. Hu, S. P. DenBaars, and S. Nakamura, “Increase in the extraction efficiency of GaN-based light-emitting diodes via surface roughening,” Appl. Phys. Lett. 84, 855–858 (2004).
[CrossRef]

Pachler, P.

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, 837–848 (2009).
[CrossRef]

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, 739–741 (2008).
[CrossRef]

Posselt, J.

M. R. Krames, M. O. Holcomb, G. E. Hofler, C. C. Coman, E. I. Chen, I. H. Tan, P. Grillot, N. F. Gardner, H. C. Chui, J. W. Huang, S. A. Stockman, F. A. Kish, M. G. Craford, T. S. Tan, C. P. Kocot, M. Hueschen, J. Posselt, B. Loh, G. Sasser, and D. Collins, “High-power truncated-inverted-pyramid (AlxGa1−x)0.5In0.5P/GaP light emitting diodes exhibiting >50% external quantum efficiency,” Appl. Phys. Lett. 75, 2365–2368 (1999).
[CrossRef]

Reeh, U.

U. Reeh, K. Höhn, N. Stath, G. Waitl, P. Schlotter, J. Schneider, and R. Schmidt, “Light-radiating semiconductor component with luminescence conversion element,” U.S. Patent6,576,930 B2 (10June2003).

Roitman, D. B.

S. D. Lester, J. N. Miller, and D. B. Roitman, “High refractive index package material and light emitting device encapsulated with such material,” U.S. Patent5,777,433 (7July1998).

Rudaz, S.

M. R. Krames, J. Bhat, D. Collins, N. F. Gardner, W. Götz, C. H. Lowery, M. Ludowise, P. S. Martin, G. Mueller, R. Mueller-Mach, S. Rudaz, D. A. Steigerwald, S. A. Stockman, and J. J. Wierer, “High-power III-nitride emitters for solid-state lighting,” Phys. Status Solidi A 192, 237–245 (2002).
[CrossRef]

Sasser, G.

M. R. Krames, M. O. Holcomb, G. E. Hofler, C. C. Coman, E. I. Chen, I. H. Tan, P. Grillot, N. F. Gardner, H. C. Chui, J. W. Huang, S. A. Stockman, F. A. Kish, M. G. Craford, T. S. Tan, C. P. Kocot, M. Hueschen, J. Posselt, B. Loh, G. Sasser, and D. Collins, “High-power truncated-inverted-pyramid (AlxGa1−x)0.5In0.5P/GaP light emitting diodes exhibiting >50% external quantum efficiency,” Appl. Phys. Lett. 75, 2365–2368 (1999).
[CrossRef]

Sato, O.

Z. Z. Gu, A. Fujishima, and O. Sato, “Fabrication of high-quality opal films with controllable thickness,” Chem. Mater. 14, 760–765 (2002).
[CrossRef]

Schlotter, P.

U. Reeh, K. Höhn, N. Stath, G. Waitl, P. Schlotter, J. Schneider, and R. Schmidt, “Light-radiating semiconductor component with luminescence conversion element,” U.S. Patent6,576,930 B2 (10June2003).

Schmidt, P. J.

G. O. Muller, R. B. Mueller-Mach, M. R. Krames, P. J. Schmidt, H. H. Bechtel, J. Meyer, J. de Graaf, and T. A. Kop, “Luminescent ceramic for a light emitting device,” U.S. Patent7,361,938 (22April2008).

Schmidt, R.

U. Reeh, K. Höhn, N. Stath, G. Waitl, P. Schlotter, J. Schneider, and R. Schmidt, “Light-radiating semiconductor component with luminescence conversion element,” U.S. Patent6,576,930 B2 (10June2003).

Schneider, J.

U. Reeh, K. Höhn, N. Stath, G. Waitl, P. Schlotter, J. Schneider, and R. Schmidt, “Light-radiating semiconductor component with luminescence conversion element,” U.S. Patent6,576,930 B2 (10June2003).

Schubert, E. F.

F. W. Mont, J. K. Kim, M. F. Schubert, E. F. Schubert, and R. W. Siegel, “High-refractive-index TiO2-nanoparticle-loaded encapsulants for light emitting diodes,” J. Appl. Phys. 103, 083120 (2008).
[CrossRef]

Y. Xi, X. Li, J. K. Kim, F. Mont, Th. Gessmann, H. Luo, and E. F. Schubert, “Quantitative assessment of diffusivity and specularity of surface textured reflectors for light extraction in light emitting diodes,” J. Vac. Sci. Technol. A 24, 1627–1631 (2006).
[CrossRef]

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

Schubert, M. F.

F. W. Mont, J. K. Kim, M. F. Schubert, E. F. Schubert, and R. W. Siegel, “High-refractive-index TiO2-nanoparticle-loaded encapsulants for light emitting diodes,” J. Appl. Phys. 103, 083120 (2008).
[CrossRef]

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, 837–848 (2009).
[CrossRef]

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, 739–741 (2008).
[CrossRef]

Seo, S. Y.

J. H. Yum, S. Y. Seo, S. Lee, and Y. E. Sung, “Y3Al5O12:Ce0.05 phosphor coatings on gallium nitride for white light emitting diodes,” J. Electrochem. Soc. 150, H47–H52 (2003).
[CrossRef]

Sharma, R.

T. Fujii, Y. Gao, R. Sharma, E. L. Hu, S. P. DenBaars, and S. Nakamura, “Increase in the extraction efficiency of GaN-based light-emitting diodes via surface roughening,” Appl. Phys. Lett. 84, 855–858 (2004).
[CrossRef]

Shih, M. H.

H. C. Chen, K. J. Chen, C. C. Lin, C. H. Wang, H. V. Han, H. H. Tsai, H. T. Kuo, S. H. Chien, M. H. Shih, and H. C. Kuo, “Improvement in uniformity of emission by ZrO2 nano-particles for white LEDs,” Nanotechnology 23, 265201 (2012).
[CrossRef]

Siegel, R. W.

F. W. Mont, J. K. Kim, M. F. Schubert, E. F. Schubert, and R. W. Siegel, “High-refractive-index TiO2-nanoparticle-loaded encapsulants for light emitting diodes,” J. Appl. Phys. 103, 083120 (2008).
[CrossRef]

Sommer, C.

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, 837–848 (2009).
[CrossRef]

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, 739–741 (2008).
[CrossRef]

Song, S. B.

J. P. Kim, M. S. Jang, W. H. Kim, J. Y. Joo, J. H. Cho, D. W. Kim, and S. B. Song, “Improvement in the color uniformity of LED by microspheres generated from phase separation,” Opt. Mater. 34, 1614–1617 (2012).
[CrossRef]

Stath, N.

U. Reeh, K. Höhn, N. Stath, G. Waitl, P. Schlotter, J. Schneider, and R. Schmidt, “Light-radiating semiconductor component with luminescence conversion element,” U.S. Patent6,576,930 B2 (10June2003).

Stavridi, M.

Steigerwald, D. A.

M. R. Krames, J. Bhat, D. Collins, N. F. Gardner, W. Götz, C. H. Lowery, M. Ludowise, P. S. Martin, G. Mueller, R. Mueller-Mach, S. Rudaz, D. A. Steigerwald, S. A. Stockman, and J. J. Wierer, “High-power III-nitride emitters for solid-state lighting,” Phys. Status Solidi A 192, 237–245 (2002).
[CrossRef]

Stockman, S. A.

M. R. Krames, J. Bhat, D. Collins, N. F. Gardner, W. Götz, C. H. Lowery, M. Ludowise, P. S. Martin, G. Mueller, R. Mueller-Mach, S. Rudaz, D. A. Steigerwald, S. A. Stockman, and J. J. Wierer, “High-power III-nitride emitters for solid-state lighting,” Phys. Status Solidi A 192, 237–245 (2002).
[CrossRef]

M. R. Krames, M. O. Holcomb, G. E. Hofler, C. C. Coman, E. I. Chen, I. H. Tan, P. Grillot, N. F. Gardner, H. C. Chui, J. W. Huang, S. A. Stockman, F. A. Kish, M. G. Craford, T. S. Tan, C. P. Kocot, M. Hueschen, J. Posselt, B. Loh, G. Sasser, and D. Collins, “High-power truncated-inverted-pyramid (AlxGa1−x)0.5In0.5P/GaP light emitting diodes exhibiting >50% external quantum efficiency,” Appl. Phys. Lett. 75, 2365–2368 (1999).
[CrossRef]

Sung, Y. E.

J. H. Yum, S. Y. Seo, S. Lee, and Y. E. Sung, “Y3Al5O12:Ce0.05 phosphor coatings on gallium nitride for white light emitting diodes,” J. Electrochem. Soc. 150, H47–H52 (2003).
[CrossRef]

Tan, C. W.

B. K. Lee, K. S. Goh, Y. L. Chin, and C. W. Tan, “Light emitting diode with gradient index layering,” U.S. Patent6,717,362 B1 (6April2004).

Tan, I. H.

M. R. Krames, M. O. Holcomb, G. E. Hofler, C. C. Coman, E. I. Chen, I. H. Tan, P. Grillot, N. F. Gardner, H. C. Chui, J. W. Huang, S. A. Stockman, F. A. Kish, M. G. Craford, T. S. Tan, C. P. Kocot, M. Hueschen, J. Posselt, B. Loh, G. Sasser, and D. Collins, “High-power truncated-inverted-pyramid (AlxGa1−x)0.5In0.5P/GaP light emitting diodes exhibiting >50% external quantum efficiency,” Appl. Phys. Lett. 75, 2365–2368 (1999).
[CrossRef]

Tan, T. S.

M. R. Krames, M. O. Holcomb, G. E. Hofler, C. C. Coman, E. I. Chen, I. H. Tan, P. Grillot, N. F. Gardner, H. C. Chui, J. W. Huang, S. A. Stockman, F. A. Kish, M. G. Craford, T. S. Tan, C. P. Kocot, M. Hueschen, J. Posselt, B. Loh, G. Sasser, and D. Collins, “High-power truncated-inverted-pyramid (AlxGa1−x)0.5In0.5P/GaP light emitting diodes exhibiting >50% external quantum efficiency,” Appl. Phys. Lett. 75, 2365–2368 (1999).
[CrossRef]

Tansu, N.

Y. K. Ee, P. Kumnorkaew, H. Tong, R. A. Arif, J. F. Gilchrist, and N. Tansu, “Enhancement of light extraction efficiency of InGaN quantum wells light-emitting diodes with polydimethylsiloxane concave microstructures,” Proc. SPIE 7231, 72310U (2009).
[CrossRef]

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, 837–848 (2009).
[CrossRef]

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, 739–741 (2008).
[CrossRef]

Tong, H.

Y. K. Ee, P. Kumnorkaew, H. Tong, R. A. Arif, J. F. Gilchrist, and N. Tansu, “Enhancement of light extraction efficiency of InGaN quantum wells light-emitting diodes with polydimethylsiloxane concave microstructures,” Proc. SPIE 7231, 72310U (2009).
[CrossRef]

Tsai, H. H.

H. C. Chen, K. J. Chen, C. C. Lin, C. H. Wang, H. V. Han, H. H. Tsai, H. T. Kuo, S. H. Chien, M. H. Shih, and H. C. Kuo, “Improvement in uniformity of emission by ZrO2 nano-particles for white LEDs,” Nanotechnology 23, 265201 (2012).
[CrossRef]

Waitl, G.

U. Reeh, K. Höhn, N. Stath, G. Waitl, P. Schlotter, J. Schneider, and R. Schmidt, “Light-radiating semiconductor component with luminescence conversion element,” U.S. Patent6,576,930 B2 (10June2003).

Wang, C. H.

H. C. Chen, K. J. Chen, C. C. Lin, C. H. Wang, H. V. Han, H. H. Tsai, H. T. Kuo, S. H. Chien, M. H. Shih, and H. C. Kuo, “Improvement in uniformity of emission by ZrO2 nano-particles for white LEDs,” Nanotechnology 23, 265201 (2012).
[CrossRef]

Wang, K.

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

Wenzl, F. P.

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, 837–848 (2009).
[CrossRef]

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, 739–741 (2008).
[CrossRef]

West, R. S.

G. Basin, A. S. Haque, C. H. Chen, R. S. West, and P. Martin, “LED with particles in encapsulant for increased light extraction and non-yellow off-state color,” U.S. Patent7,791,093 (7September2010).

Wierer, J. J.

M. R. Krames, J. Bhat, D. Collins, N. F. Gardner, W. Götz, C. H. Lowery, M. Ludowise, P. S. Martin, G. Mueller, R. Mueller-Mach, S. Rudaz, D. A. Steigerwald, S. A. Stockman, and J. J. Wierer, “High-power III-nitride emitters for solid-state lighting,” Phys. Status Solidi A 192, 237–245 (2002).
[CrossRef]

Xi, Y.

Y. Xi, X. Li, J. K. Kim, F. Mont, Th. Gessmann, H. Luo, and E. F. Schubert, “Quantitative assessment of diffusivity and specularity of surface textured reflectors for light extraction in light emitting diodes,” J. Vac. Sci. Technol. A 24, 1627–1631 (2006).
[CrossRef]

Yum, J. H.

J. H. Yum, S. Y. Seo, S. Lee, and Y. E. Sung, “Y3Al5O12:Ce0.05 phosphor coatings on gallium nitride for white light emitting diodes,” J. Electrochem. Soc. 150, H47–H52 (2003).
[CrossRef]

Appl. Opt. (1)

Appl. Phys. Lett. (2)

M. R. Krames, M. O. Holcomb, G. E. Hofler, C. C. Coman, E. I. Chen, I. H. Tan, P. Grillot, N. F. Gardner, H. C. Chui, J. W. Huang, S. A. Stockman, F. A. Kish, M. G. Craford, T. S. Tan, C. P. Kocot, M. Hueschen, J. Posselt, B. Loh, G. Sasser, and D. Collins, “High-power truncated-inverted-pyramid (AlxGa1−x)0.5In0.5P/GaP light emitting diodes exhibiting >50% external quantum efficiency,” Appl. Phys. Lett. 75, 2365–2368 (1999).
[CrossRef]

T. Fujii, Y. Gao, R. Sharma, E. L. Hu, S. P. DenBaars, and S. Nakamura, “Increase in the extraction efficiency of GaN-based light-emitting diodes via surface roughening,” Appl. Phys. Lett. 84, 855–858 (2004).
[CrossRef]

Chem. Mater. (1)

Z. Z. Gu, A. Fujishima, and O. Sato, “Fabrication of high-quality opal films with controllable thickness,” Chem. Mater. 14, 760–765 (2002).
[CrossRef]

IEEE Photon. Technol. Lett. (2)

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, 739–741 (2008).
[CrossRef]

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

J. Appl. Phys. (1)

F. W. Mont, J. K. Kim, M. F. Schubert, E. F. Schubert, and R. W. Siegel, “High-refractive-index TiO2-nanoparticle-loaded encapsulants for light emitting diodes,” J. Appl. Phys. 103, 083120 (2008).
[CrossRef]

J. Electrochem. Soc. (1)

J. H. Yum, S. Y. Seo, S. Lee, and Y. E. Sung, “Y3Al5O12:Ce0.05 phosphor coatings on gallium nitride for white light emitting diodes,” J. Electrochem. Soc. 150, H47–H52 (2003).
[CrossRef]

J. Vac. Sci. Technol. A (1)

Y. Xi, X. Li, J. K. Kim, F. Mont, Th. Gessmann, H. Luo, and E. F. Schubert, “Quantitative assessment of diffusivity and specularity of surface textured reflectors for light extraction in light emitting diodes,” J. Vac. Sci. Technol. A 24, 1627–1631 (2006).
[CrossRef]

Nanotechnology (1)

H. C. Chen, K. J. Chen, C. C. Lin, C. H. Wang, H. V. Han, H. H. Tsai, H. T. Kuo, S. H. Chien, M. H. Shih, and H. C. Kuo, “Improvement in uniformity of emission by ZrO2 nano-particles for white LEDs,” Nanotechnology 23, 265201 (2012).
[CrossRef]

Opt. Mater. (2)

J. P. Kim, M. S. Jang, W. H. Kim, J. Y. Joo, J. H. Cho, D. W. Kim, and S. B. Song, “Improvement in the color uniformity of LED by microspheres generated from phase separation,” Opt. Mater. 34, 1614–1617 (2012).
[CrossRef]

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, 837–848 (2009).
[CrossRef]

Phys. Status Solidi A (1)

M. R. Krames, J. Bhat, D. Collins, N. F. Gardner, W. Götz, C. H. Lowery, M. Ludowise, P. S. Martin, G. Mueller, R. Mueller-Mach, S. Rudaz, D. A. Steigerwald, S. A. Stockman, and J. J. Wierer, “High-power III-nitride emitters for solid-state lighting,” Phys. Status Solidi A 192, 237–245 (2002).
[CrossRef]

Proc. SPIE (2)

K. C. Lee, S. M. Kim, and J. H. Moon, “The effects of titania diffuser on angular color homogeneity in the phosphor conformal coated white LEDs,” Proc. SPIE 7784, 778410 (2010).
[CrossRef]

Y. K. Ee, P. Kumnorkaew, H. Tong, R. A. Arif, J. F. Gilchrist, and N. Tansu, “Enhancement of light extraction efficiency of InGaN quantum wells light-emitting diodes with polydimethylsiloxane concave microstructures,” Proc. SPIE 7231, 72310U (2009).
[CrossRef]

Other (7)

B. P. Loh, N. W. Medendorp, P. Andrews, Y. Fu, M. Laughner, and R. Letoquin, “Method of uniform phosphor chip coating and LED package fabricated using method,” U.S. Patent7,943,952 (17May2011).

G. O. Muller, R. B. Mueller-Mach, M. R. Krames, P. J. Schmidt, H. H. Bechtel, J. Meyer, J. de Graaf, and T. A. Kop, “Luminescent ceramic for a light emitting device,” U.S. Patent7,361,938 (22April2008).

G. Basin, A. S. Haque, C. H. Chen, R. S. West, and P. Martin, “LED with particles in encapsulant for increased light extraction and non-yellow off-state color,” U.S. Patent7,791,093 (7September2010).

B. K. Lee, K. S. Goh, Y. L. Chin, and C. W. Tan, “Light emitting diode with gradient index layering,” U.S. Patent6,717,362 B1 (6April2004).

U. Reeh, K. Höhn, N. Stath, G. Waitl, P. Schlotter, J. Schneider, and R. Schmidt, “Light-radiating semiconductor component with luminescence conversion element,” U.S. Patent6,576,930 B2 (10June2003).

S. D. Lester, J. N. Miller, and D. B. Roitman, “High refractive index package material and light emitting device encapsulated with such material,” U.S. Patent5,777,433 (7July1998).

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

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Figures (7)

Fig. 1.
Fig. 1.

Fabrication processes of diffuser-loaded encapsulation white LEDs.

Fig. 2.
Fig. 2.

White LED samples with nondiffuser, MF Resin diffuser, and CaCO3 diffuser-loaded encapsulation.

Fig. 3.
Fig. 3.

SEM images of MF resin and CaCO3 diffuser particles.

Fig. 4.
Fig. 4.

Cross section of diffuser-loaded encapsulation white LED after polishing.

Fig. 5.
Fig. 5.

CCT uniformity comparison of light spot for nondiffuser, 1% MF resin diffuser, and 1% CaCO3 diffuser-loaded encapsulation white LEDs.

Fig. 6.
Fig. 6.

Angular CCT distribution of nondiffuser, 10% MF resin diffuser, and 10% CaCO3 diffuser-loaded encapsulation white LEDs.

Fig. 7.
Fig. 7.

Change of spatial CCT variance and luminous efficacy drop of MF resin diffuser and CaCO3 diffuser-loaded encapsulation white LEDs.

Equations (3)

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

n¯=n¯hostVhost+n¯loadVloadVhost+Vload,
Fluorescence=Absorption+Excitation+Emission.
Ein=Eunabsorbed+Ea.

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