Abstract

We demonstrate a freeform lens to enhance the angular color uniformity (ACU) of white light-emitting diodes (LEDs) whose phosphor layers were coated by freely dispersed coating processes. Monte Carlo ray tracing simulation results indicated that the ACU of the modified LED integrated with the freeform lens significantly increased from 0.334 to 0.957, compared with the traditional LED. Enhancement of ACU reached as high as 186.5%. Moreover, the ACU of the modified LED was not only at a high level, but also stable when the shape of the phosphor layer changed. The freeform lens provided an effective way to achieve white LEDs with high ACU at low cost.

© 2010 Optical Society of America

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  1. M. R. Krames, O. B. Shchekin, R. M. Mach, G. O. Mueller, L. Zhou, G. Harbers, and M. G. Craford, J. Display Technol. 3, 160 (2007).
    [CrossRef]
  2. E. F. Schubert, Light-Emitting Diodes (Cambridge U. Press, 2006).
    [CrossRef]
  3. S. Liu and X. B. Luo, LED Packaging for Lighting Applications: Design, Manufacturing and Testing (Wiley, 2010), to be published.
  4. C. Sommer, F. P. Wenzl, P. Hartmann, P. Pachler, M. Schweighart, S. Tasch, and G. Leising, IEEE Photonics Technol. Lett. 20, 739 (2008).
    [CrossRef]
  5. Z. Y. Liu, S. Liu, K. Wang, and X. B. Luo, IEEE Photonics Technol. Lett. 20, 2027 (2008).
    [CrossRef]
  6. R. C. Jordan, J. Bauer, and H. Oppermann, Proc. SPIE 6198, 61980B (2006).
    [CrossRef]
  7. W. D. Collins, M. R. Krames, G. J. Verhoeckx, and N. J. M. Leth, “Using electrophoresis to produce a conformally coated phosphor-converted light emitting semiconductor,” U.S. patent 6,576,488 (10 June 2003).
  8. J. H. Yum, S. Y. Seo, S. Lee and Y. E. Sung, Proc. SPIE 4445, 60 (2001).
    [CrossRef]
  9. G. H. Negley and M. Leung, “Methods of coating semiconductor light emitting elements by evaporating solvent from a suspension,” U.S. patent 7,217,583 (15 May 2007).
  10. B. Braune, K. Petersen, J. Strauss, P. Kromotis, and M. Kaempf, Proc. SPIE 6486, 64860X (2007).
    [CrossRef]
  11. H. Wu, N. Narendran, Y. Gu, and A. Bierman, Proc. SPIE 6669, 666905 (2007).
    [CrossRef]
  12. F. Chen, S. Liu, K. Wang, Z. Y. Liu, and X. B. Luo, Opt. Eng. 48, 123002 (2009).
    [CrossRef]
  13. T. X. Lee, K. F. Gao, W. T. Chien, and C. C. Sun, Opt. Express 15, 6670 (2007).
    [CrossRef] [PubMed]
  14. Z. Y. Liu, S. Liu, K. Wang, and X. B. Luo, “Studies on optical consistency of white LEDs affected by phosphor thickness and concentration using optical simulation,” IEEE Trans. Compon. Packag. Technol. (to be published).

2009

F. Chen, S. Liu, K. Wang, Z. Y. Liu, and X. B. Luo, Opt. Eng. 48, 123002 (2009).
[CrossRef]

2008

C. Sommer, F. P. Wenzl, P. Hartmann, P. Pachler, M. Schweighart, S. Tasch, and G. Leising, IEEE Photonics Technol. Lett. 20, 739 (2008).
[CrossRef]

Z. Y. Liu, S. Liu, K. Wang, and X. B. Luo, IEEE Photonics Technol. Lett. 20, 2027 (2008).
[CrossRef]

2007

2006

R. C. Jordan, J. Bauer, and H. Oppermann, Proc. SPIE 6198, 61980B (2006).
[CrossRef]

2001

J. H. Yum, S. Y. Seo, S. Lee and Y. E. Sung, Proc. SPIE 4445, 60 (2001).
[CrossRef]

Bauer, J.

R. C. Jordan, J. Bauer, and H. Oppermann, Proc. SPIE 6198, 61980B (2006).
[CrossRef]

Bierman, A.

H. Wu, N. Narendran, Y. Gu, and A. Bierman, Proc. SPIE 6669, 666905 (2007).
[CrossRef]

Braune, B.

B. Braune, K. Petersen, J. Strauss, P. Kromotis, and M. Kaempf, Proc. SPIE 6486, 64860X (2007).
[CrossRef]

Chen, F.

F. Chen, S. Liu, K. Wang, Z. Y. Liu, and X. B. Luo, Opt. Eng. 48, 123002 (2009).
[CrossRef]

Chien, W. T.

Collins, W. D.

W. D. Collins, M. R. Krames, G. J. Verhoeckx, and N. J. M. Leth, “Using electrophoresis to produce a conformally coated phosphor-converted light emitting semiconductor,” U.S. patent 6,576,488 (10 June 2003).

Craford, M. G.

Gao, K. F.

Gu, Y.

H. Wu, N. Narendran, Y. Gu, and A. Bierman, Proc. SPIE 6669, 666905 (2007).
[CrossRef]

Harbers, G.

Hartmann, P.

C. Sommer, F. P. Wenzl, P. Hartmann, P. Pachler, M. Schweighart, S. Tasch, and G. Leising, IEEE Photonics Technol. Lett. 20, 739 (2008).
[CrossRef]

Jordan, R. C.

R. C. Jordan, J. Bauer, and H. Oppermann, Proc. SPIE 6198, 61980B (2006).
[CrossRef]

Kaempf, M.

B. Braune, K. Petersen, J. Strauss, P. Kromotis, and M. Kaempf, Proc. SPIE 6486, 64860X (2007).
[CrossRef]

Krames, M. R.

M. R. Krames, O. B. Shchekin, R. M. Mach, G. O. Mueller, L. Zhou, G. Harbers, and M. G. Craford, J. Display Technol. 3, 160 (2007).
[CrossRef]

W. D. Collins, M. R. Krames, G. J. Verhoeckx, and N. J. M. Leth, “Using electrophoresis to produce a conformally coated phosphor-converted light emitting semiconductor,” U.S. patent 6,576,488 (10 June 2003).

Kromotis, P.

B. Braune, K. Petersen, J. Strauss, P. Kromotis, and M. Kaempf, Proc. SPIE 6486, 64860X (2007).
[CrossRef]

Lee, S.

J. H. Yum, S. Y. Seo, S. Lee and Y. E. Sung, Proc. SPIE 4445, 60 (2001).
[CrossRef]

Lee, T. X.

Leising, G.

C. Sommer, F. P. Wenzl, P. Hartmann, P. Pachler, M. Schweighart, S. Tasch, and G. Leising, IEEE Photonics Technol. Lett. 20, 739 (2008).
[CrossRef]

Leth, N. J. M.

W. D. Collins, M. R. Krames, G. J. Verhoeckx, and N. J. M. Leth, “Using electrophoresis to produce a conformally coated phosphor-converted light emitting semiconductor,” U.S. patent 6,576,488 (10 June 2003).

Leung, M.

G. H. Negley and M. Leung, “Methods of coating semiconductor light emitting elements by evaporating solvent from a suspension,” U.S. patent 7,217,583 (15 May 2007).

Liu, S.

F. Chen, S. Liu, K. Wang, Z. Y. Liu, and X. B. Luo, Opt. Eng. 48, 123002 (2009).
[CrossRef]

Z. Y. Liu, S. Liu, K. Wang, and X. B. Luo, IEEE Photonics Technol. Lett. 20, 2027 (2008).
[CrossRef]

S. Liu and X. B. Luo, LED Packaging for Lighting Applications: Design, Manufacturing and Testing (Wiley, 2010), to be published.

Z. Y. Liu, S. Liu, K. Wang, and X. B. Luo, “Studies on optical consistency of white LEDs affected by phosphor thickness and concentration using optical simulation,” IEEE Trans. Compon. Packag. Technol. (to be published).

Liu, Z. Y.

F. Chen, S. Liu, K. Wang, Z. Y. Liu, and X. B. Luo, Opt. Eng. 48, 123002 (2009).
[CrossRef]

Z. Y. Liu, S. Liu, K. Wang, and X. B. Luo, IEEE Photonics Technol. Lett. 20, 2027 (2008).
[CrossRef]

Z. Y. Liu, S. Liu, K. Wang, and X. B. Luo, “Studies on optical consistency of white LEDs affected by phosphor thickness and concentration using optical simulation,” IEEE Trans. Compon. Packag. Technol. (to be published).

Luo, X. B.

F. Chen, S. Liu, K. Wang, Z. Y. Liu, and X. B. Luo, Opt. Eng. 48, 123002 (2009).
[CrossRef]

Z. Y. Liu, S. Liu, K. Wang, and X. B. Luo, IEEE Photonics Technol. Lett. 20, 2027 (2008).
[CrossRef]

S. Liu and X. B. Luo, LED Packaging for Lighting Applications: Design, Manufacturing and Testing (Wiley, 2010), to be published.

Z. Y. Liu, S. Liu, K. Wang, and X. B. Luo, “Studies on optical consistency of white LEDs affected by phosphor thickness and concentration using optical simulation,” IEEE Trans. Compon. Packag. Technol. (to be published).

Mach, R. M.

Mueller, G. O.

Narendran, N.

H. Wu, N. Narendran, Y. Gu, and A. Bierman, Proc. SPIE 6669, 666905 (2007).
[CrossRef]

Negley, G. H.

G. H. Negley and M. Leung, “Methods of coating semiconductor light emitting elements by evaporating solvent from a suspension,” U.S. patent 7,217,583 (15 May 2007).

Oppermann, H.

R. C. Jordan, J. Bauer, and H. Oppermann, Proc. SPIE 6198, 61980B (2006).
[CrossRef]

Pachler, P.

C. Sommer, F. P. Wenzl, P. Hartmann, P. Pachler, M. Schweighart, S. Tasch, and G. Leising, IEEE Photonics Technol. Lett. 20, 739 (2008).
[CrossRef]

Petersen, K.

B. Braune, K. Petersen, J. Strauss, P. Kromotis, and M. Kaempf, Proc. SPIE 6486, 64860X (2007).
[CrossRef]

Schubert, E. F.

E. F. Schubert, Light-Emitting Diodes (Cambridge U. Press, 2006).
[CrossRef]

Schweighart, M.

C. Sommer, F. P. Wenzl, P. Hartmann, P. Pachler, M. Schweighart, S. Tasch, and G. Leising, IEEE Photonics Technol. Lett. 20, 739 (2008).
[CrossRef]

Seo, S. Y.

J. H. Yum, S. Y. Seo, S. Lee and Y. E. Sung, Proc. SPIE 4445, 60 (2001).
[CrossRef]

Shchekin, O. B.

Sommer, C.

C. Sommer, F. P. Wenzl, P. Hartmann, P. Pachler, M. Schweighart, S. Tasch, and G. Leising, IEEE Photonics Technol. Lett. 20, 739 (2008).
[CrossRef]

Strauss, J.

B. Braune, K. Petersen, J. Strauss, P. Kromotis, and M. Kaempf, Proc. SPIE 6486, 64860X (2007).
[CrossRef]

Sun, C. C.

Sung, Y. E.

J. H. Yum, S. Y. Seo, S. Lee and Y. E. Sung, Proc. SPIE 4445, 60 (2001).
[CrossRef]

Tasch, S.

C. Sommer, F. P. Wenzl, P. Hartmann, P. Pachler, M. Schweighart, S. Tasch, and G. Leising, IEEE Photonics Technol. Lett. 20, 739 (2008).
[CrossRef]

Verhoeckx, G. J.

W. D. Collins, M. R. Krames, G. J. Verhoeckx, and N. J. M. Leth, “Using electrophoresis to produce a conformally coated phosphor-converted light emitting semiconductor,” U.S. patent 6,576,488 (10 June 2003).

Wang, K.

F. Chen, S. Liu, K. Wang, Z. Y. Liu, and X. B. Luo, Opt. Eng. 48, 123002 (2009).
[CrossRef]

Z. Y. Liu, S. Liu, K. Wang, and X. B. Luo, IEEE Photonics Technol. Lett. 20, 2027 (2008).
[CrossRef]

Z. Y. Liu, S. Liu, K. Wang, and X. B. Luo, “Studies on optical consistency of white LEDs affected by phosphor thickness and concentration using optical simulation,” IEEE Trans. Compon. Packag. Technol. (to be published).

Wenzl, F. P.

C. Sommer, F. P. Wenzl, P. Hartmann, P. Pachler, M. Schweighart, S. Tasch, and G. Leising, IEEE Photonics Technol. Lett. 20, 739 (2008).
[CrossRef]

Wu, H.

H. Wu, N. Narendran, Y. Gu, and A. Bierman, Proc. SPIE 6669, 666905 (2007).
[CrossRef]

Yum, J. H.

J. H. Yum, S. Y. Seo, S. Lee and Y. E. Sung, Proc. SPIE 4445, 60 (2001).
[CrossRef]

Zhou, L.

IEEE Photonics Technol. Lett.

C. Sommer, F. P. Wenzl, P. Hartmann, P. Pachler, M. Schweighart, S. Tasch, and G. Leising, IEEE Photonics Technol. Lett. 20, 739 (2008).
[CrossRef]

Z. Y. Liu, S. Liu, K. Wang, and X. B. Luo, IEEE Photonics Technol. Lett. 20, 2027 (2008).
[CrossRef]

J. Display Technol.

Opt. Eng.

F. Chen, S. Liu, K. Wang, Z. Y. Liu, and X. B. Luo, Opt. Eng. 48, 123002 (2009).
[CrossRef]

Opt. Express

Proc. SPIE

B. Braune, K. Petersen, J. Strauss, P. Kromotis, and M. Kaempf, Proc. SPIE 6486, 64860X (2007).
[CrossRef]

H. Wu, N. Narendran, Y. Gu, and A. Bierman, Proc. SPIE 6669, 666905 (2007).
[CrossRef]

R. C. Jordan, J. Bauer, and H. Oppermann, Proc. SPIE 6198, 61980B (2006).
[CrossRef]

J. H. Yum, S. Y. Seo, S. Lee and Y. E. Sung, Proc. SPIE 4445, 60 (2001).
[CrossRef]

Other

G. H. Negley and M. Leung, “Methods of coating semiconductor light emitting elements by evaporating solvent from a suspension,” U.S. patent 7,217,583 (15 May 2007).

E. F. Schubert, Light-Emitting Diodes (Cambridge U. Press, 2006).
[CrossRef]

S. Liu and X. B. Luo, LED Packaging for Lighting Applications: Design, Manufacturing and Testing (Wiley, 2010), to be published.

W. D. Collins, M. R. Krames, G. J. Verhoeckx, and N. J. M. Leth, “Using electrophoresis to produce a conformally coated phosphor-converted light emitting semiconductor,” U.S. patent 6,576,488 (10 June 2003).

Z. Y. Liu, S. Liu, K. Wang, and X. B. Luo, “Studies on optical consistency of white LEDs affected by phosphor thickness and concentration using optical simulation,” IEEE Trans. Compon. Packag. Technol. (to be published).

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Figures (5)

Fig. 1
Fig. 1

Schematic of light output of (a) the traditional LED and (b) the modified LED.

Fig. 2
Fig. 2

Schematic of optical power of center and edge points in the far field of (a) the traditional LED and (b) the modified LED.

Fig. 3
Fig. 3

Optical models of (a) the traditional LED and (b) the modified LED.

Fig. 4
Fig. 4

(a) ACU and (b) LIDs of the traditional LED and the modified LED.

Fig. 5
Fig. 5

Effects of (a) radii and (b) heights of phosphor layers on the ACU of LEDs.

Equations (3)

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

Y 0 B 0 < Y 0 + Y 2 B 0 + B 2 ,
Y 1 + Y 3 B 1 + B 3 < Y 1 B 1 ,
Y 0 B 0 < Y 0 + Y 2 B 0 + B 2 = Y 1 + Y 3 B 1 + B 3 < Y 1 B 1 .

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