Abstract

In this study, we present a smart design concept for extremely thin free-form (FF) micro-optical elements (MOEs) for uniform illumination in direct-lit LED luminaire systems with a large distance to height ratio (DHR). A design example for a FF-MOE with a height of only 50 µm that allows for a DHR value of more than 3 is presented. In particular, it is also shown that the arrangement of the FF-MOE with respect to the substrate (bottom side or top side) is of essential relevance in order to achieve large DHR values. The applicability of these FF-MOEs is demonstrated by comparing the simulation and experimental results of a demonstrator box mimicking a thin direct-lit luminaire.

© 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

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References

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  1. Y. Narukawa, “White-light LEDS,” Opt. Photonics News 15(4), 24 (2004).
    [Crossref]
  2. J. Cho, J. H. Park, J. K. Kim, and E. F. Schubert, “White light-emitting diodes: history, progress, and future,” Laser Photonics Rev. 11(2), 1600147 (2017).
    [Crossref]
  3. Z. Qin, K. Wang, F. Chen, X. Luo, and S. Liu, “Analysis of condition for uniform lighting generated by array of light emitting diodes with large view angle,” Opt. Express 18(16), 17460–17476 (2010).
    [Crossref] [PubMed]
  4. J. Yan, D. Li, Z. Wang, and W. Rao, “An iterative method for the uniformity improvement of edge-lit backlight,” Adv. Optoelectron. 2016, 1–5 (2016).
    [Crossref]
  5. M. H. Shin, J. Y. Lee, H. R. Moon, and Y. J. Kim, “Proposal and design of hybrid light guide plate based on aspheric concave surface and micropatterns to improve illuminance and color uniformity for LED display,” Jpn. J. Appl. Phys. 53, 8S2 (2014).
  6. R. Hu, H. Zheng, C. Ji, S. Liu, and X. Luo, “A method to design freeform lens for uniform illumination in direct-lit led backlight with high distance-height ratio,” ICEPT-HDP 2012 Proc. - 2012 13th Int. Conf. Electron. Packag. Technol. High Density Packag. 1474–1478 (2012).
  7. B. Xie, R. Hu, Q. Chen, X. Yu, D. Wu, K. Wang, and X. Luo, “Design of a brightness-enhancement-film-adaptive freeform lens to enhance overall performance in direct-lit light-emitting diode backlighting,” Appl. Opt. 54(17), 5542–5548 (2015).
    [Crossref] [PubMed]
  8. A. J.-W. Whang, Y.-Y. Chen, and Y.-T. Teng, “Designing uniform illumination systems by surface-tailored lens and configurations of LED arrays,” J. Disp. Technol. 5(3), 94–103 (2009).
    [Crossref]
  9. Z. T. Ye, H.-C. Kuo, and C.-H. Chen, “Thin hollow light guide for high-efficiency planar illuminator,” Appl. Opt. 54(28), E23–E29 (2015).
    [Crossref] [PubMed]
  10. H. Wu, X. Zhang, and P. Ge, “Double freeform surfaces lens design for LED uniform illumination with high distance–height ratio,” Opt. Laser Technol. 73, 166–172 (2015).
    [Crossref]
  11. I. Moreno, M. Avendaño-Alejo, and R. I. Tzonchev, “Designing light-emitting diode arrays for uniform near-field irradiance,” Appl. Opt. 45(10), 2265–2272 (2006).
    [Crossref] [PubMed]
  12. F. Fang, N. Zhang, and X. Zhang, “Precision injection molding of freeform optics,” Adv. Opt. Technol. 5, 303–324 (2016).
  13. F. Z. Fang, X. D. Zhang, A. Weckenmann, G. X. Zhang, and C. Evans, “Manufacturing and measurement of freeform optics,” CIRP Ann. Manuf. Technol. 62(2), 823–846 (2013).
    [Crossref]
  14. T. Blalock, K. Medicus, and J. DeGroote Nelson, “Fabrication of freeform optics,” Proc. SPIE 9575, 95750H (2015).
  15. L. Li and A. Y. Yi, “Design and fabrication of a freeform microlens array for uniform beam shaping,” Microsyst. Technol. 17(12), 1713–1720 (2011).
    [Crossref]
  16. C. Leiner, W. Nemitz, S. Schweitzer, F. P. Wenzl, and C. Sommer, “Smart freeform optics solution for an extremely thin direct-lit application,” Proc. SPIE 9889, 988911 (2016).
    [Crossref]
  17. C. Leiner, W. Nemitz, S. Schweitzer, F. P. Wenzl, L. Kuna, F. Reil, P. Hartmann, and C. Sommer, “Thin direct-lit application for general lighting realized by freeform micro-optical elements,” Proc. SPIE 9955, 99550E (2016).
    [Crossref]
  18. L. Kuna, C. Leiner, W. Nemitz, F. Reil, P. Hartmann, F.-P. Wenzl, and C. Sommer, “Optical design of freeform micro-optical elements and their fabrication combining maskless laser direct write lithography and replication by imprinting,” J. Photon. Energy. 7(1), 016002 (2017).
    [Crossref]

2017 (2)

J. Cho, J. H. Park, J. K. Kim, and E. F. Schubert, “White light-emitting diodes: history, progress, and future,” Laser Photonics Rev. 11(2), 1600147 (2017).
[Crossref]

L. Kuna, C. Leiner, W. Nemitz, F. Reil, P. Hartmann, F.-P. Wenzl, and C. Sommer, “Optical design of freeform micro-optical elements and their fabrication combining maskless laser direct write lithography and replication by imprinting,” J. Photon. Energy. 7(1), 016002 (2017).
[Crossref]

2016 (4)

C. Leiner, W. Nemitz, S. Schweitzer, F. P. Wenzl, and C. Sommer, “Smart freeform optics solution for an extremely thin direct-lit application,” Proc. SPIE 9889, 988911 (2016).
[Crossref]

C. Leiner, W. Nemitz, S. Schweitzer, F. P. Wenzl, L. Kuna, F. Reil, P. Hartmann, and C. Sommer, “Thin direct-lit application for general lighting realized by freeform micro-optical elements,” Proc. SPIE 9955, 99550E (2016).
[Crossref]

J. Yan, D. Li, Z. Wang, and W. Rao, “An iterative method for the uniformity improvement of edge-lit backlight,” Adv. Optoelectron. 2016, 1–5 (2016).
[Crossref]

F. Fang, N. Zhang, and X. Zhang, “Precision injection molding of freeform optics,” Adv. Opt. Technol. 5, 303–324 (2016).

2015 (4)

H. Wu, X. Zhang, and P. Ge, “Double freeform surfaces lens design for LED uniform illumination with high distance–height ratio,” Opt. Laser Technol. 73, 166–172 (2015).
[Crossref]

T. Blalock, K. Medicus, and J. DeGroote Nelson, “Fabrication of freeform optics,” Proc. SPIE 9575, 95750H (2015).

B. Xie, R. Hu, Q. Chen, X. Yu, D. Wu, K. Wang, and X. Luo, “Design of a brightness-enhancement-film-adaptive freeform lens to enhance overall performance in direct-lit light-emitting diode backlighting,” Appl. Opt. 54(17), 5542–5548 (2015).
[Crossref] [PubMed]

Z. T. Ye, H.-C. Kuo, and C.-H. Chen, “Thin hollow light guide for high-efficiency planar illuminator,” Appl. Opt. 54(28), E23–E29 (2015).
[Crossref] [PubMed]

2014 (1)

M. H. Shin, J. Y. Lee, H. R. Moon, and Y. J. Kim, “Proposal and design of hybrid light guide plate based on aspheric concave surface and micropatterns to improve illuminance and color uniformity for LED display,” Jpn. J. Appl. Phys. 53, 8S2 (2014).

2013 (1)

F. Z. Fang, X. D. Zhang, A. Weckenmann, G. X. Zhang, and C. Evans, “Manufacturing and measurement of freeform optics,” CIRP Ann. Manuf. Technol. 62(2), 823–846 (2013).
[Crossref]

2011 (1)

L. Li and A. Y. Yi, “Design and fabrication of a freeform microlens array for uniform beam shaping,” Microsyst. Technol. 17(12), 1713–1720 (2011).
[Crossref]

2010 (1)

2009 (1)

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

2006 (1)

2004 (1)

Y. Narukawa, “White-light LEDS,” Opt. Photonics News 15(4), 24 (2004).
[Crossref]

Avendaño-Alejo, M.

Blalock, T.

T. Blalock, K. Medicus, and J. DeGroote Nelson, “Fabrication of freeform optics,” Proc. SPIE 9575, 95750H (2015).

Chen, C.-H.

Chen, F.

Chen, Q.

Chen, Y.-Y.

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

Cho, J.

J. Cho, J. H. Park, J. K. Kim, and E. F. Schubert, “White light-emitting diodes: history, progress, and future,” Laser Photonics Rev. 11(2), 1600147 (2017).
[Crossref]

DeGroote Nelson, J.

T. Blalock, K. Medicus, and J. DeGroote Nelson, “Fabrication of freeform optics,” Proc. SPIE 9575, 95750H (2015).

Evans, C.

F. Z. Fang, X. D. Zhang, A. Weckenmann, G. X. Zhang, and C. Evans, “Manufacturing and measurement of freeform optics,” CIRP Ann. Manuf. Technol. 62(2), 823–846 (2013).
[Crossref]

Fang, F.

F. Fang, N. Zhang, and X. Zhang, “Precision injection molding of freeform optics,” Adv. Opt. Technol. 5, 303–324 (2016).

Fang, F. Z.

F. Z. Fang, X. D. Zhang, A. Weckenmann, G. X. Zhang, and C. Evans, “Manufacturing and measurement of freeform optics,” CIRP Ann. Manuf. Technol. 62(2), 823–846 (2013).
[Crossref]

Ge, P.

H. Wu, X. Zhang, and P. Ge, “Double freeform surfaces lens design for LED uniform illumination with high distance–height ratio,” Opt. Laser Technol. 73, 166–172 (2015).
[Crossref]

Hartmann, P.

L. Kuna, C. Leiner, W. Nemitz, F. Reil, P. Hartmann, F.-P. Wenzl, and C. Sommer, “Optical design of freeform micro-optical elements and their fabrication combining maskless laser direct write lithography and replication by imprinting,” J. Photon. Energy. 7(1), 016002 (2017).
[Crossref]

C. Leiner, W. Nemitz, S. Schweitzer, F. P. Wenzl, L. Kuna, F. Reil, P. Hartmann, and C. Sommer, “Thin direct-lit application for general lighting realized by freeform micro-optical elements,” Proc. SPIE 9955, 99550E (2016).
[Crossref]

Hu, R.

Kim, J. K.

J. Cho, J. H. Park, J. K. Kim, and E. F. Schubert, “White light-emitting diodes: history, progress, and future,” Laser Photonics Rev. 11(2), 1600147 (2017).
[Crossref]

Kim, Y. J.

M. H. Shin, J. Y. Lee, H. R. Moon, and Y. J. Kim, “Proposal and design of hybrid light guide plate based on aspheric concave surface and micropatterns to improve illuminance and color uniformity for LED display,” Jpn. J. Appl. Phys. 53, 8S2 (2014).

Kuna, L.

L. Kuna, C. Leiner, W. Nemitz, F. Reil, P. Hartmann, F.-P. Wenzl, and C. Sommer, “Optical design of freeform micro-optical elements and their fabrication combining maskless laser direct write lithography and replication by imprinting,” J. Photon. Energy. 7(1), 016002 (2017).
[Crossref]

C. Leiner, W. Nemitz, S. Schweitzer, F. P. Wenzl, L. Kuna, F. Reil, P. Hartmann, and C. Sommer, “Thin direct-lit application for general lighting realized by freeform micro-optical elements,” Proc. SPIE 9955, 99550E (2016).
[Crossref]

Kuo, H.-C.

Lee, J. Y.

M. H. Shin, J. Y. Lee, H. R. Moon, and Y. J. Kim, “Proposal and design of hybrid light guide plate based on aspheric concave surface and micropatterns to improve illuminance and color uniformity for LED display,” Jpn. J. Appl. Phys. 53, 8S2 (2014).

Leiner, C.

L. Kuna, C. Leiner, W. Nemitz, F. Reil, P. Hartmann, F.-P. Wenzl, and C. Sommer, “Optical design of freeform micro-optical elements and their fabrication combining maskless laser direct write lithography and replication by imprinting,” J. Photon. Energy. 7(1), 016002 (2017).
[Crossref]

C. Leiner, W. Nemitz, S. Schweitzer, F. P. Wenzl, L. Kuna, F. Reil, P. Hartmann, and C. Sommer, “Thin direct-lit application for general lighting realized by freeform micro-optical elements,” Proc. SPIE 9955, 99550E (2016).
[Crossref]

C. Leiner, W. Nemitz, S. Schweitzer, F. P. Wenzl, and C. Sommer, “Smart freeform optics solution for an extremely thin direct-lit application,” Proc. SPIE 9889, 988911 (2016).
[Crossref]

Li, D.

J. Yan, D. Li, Z. Wang, and W. Rao, “An iterative method for the uniformity improvement of edge-lit backlight,” Adv. Optoelectron. 2016, 1–5 (2016).
[Crossref]

Li, L.

L. Li and A. Y. Yi, “Design and fabrication of a freeform microlens array for uniform beam shaping,” Microsyst. Technol. 17(12), 1713–1720 (2011).
[Crossref]

Liu, S.

Luo, X.

Medicus, K.

T. Blalock, K. Medicus, and J. DeGroote Nelson, “Fabrication of freeform optics,” Proc. SPIE 9575, 95750H (2015).

Moon, H. R.

M. H. Shin, J. Y. Lee, H. R. Moon, and Y. J. Kim, “Proposal and design of hybrid light guide plate based on aspheric concave surface and micropatterns to improve illuminance and color uniformity for LED display,” Jpn. J. Appl. Phys. 53, 8S2 (2014).

Moreno, I.

Narukawa, Y.

Y. Narukawa, “White-light LEDS,” Opt. Photonics News 15(4), 24 (2004).
[Crossref]

Nemitz, W.

L. Kuna, C. Leiner, W. Nemitz, F. Reil, P. Hartmann, F.-P. Wenzl, and C. Sommer, “Optical design of freeform micro-optical elements and their fabrication combining maskless laser direct write lithography and replication by imprinting,” J. Photon. Energy. 7(1), 016002 (2017).
[Crossref]

C. Leiner, W. Nemitz, S. Schweitzer, F. P. Wenzl, L. Kuna, F. Reil, P. Hartmann, and C. Sommer, “Thin direct-lit application for general lighting realized by freeform micro-optical elements,” Proc. SPIE 9955, 99550E (2016).
[Crossref]

C. Leiner, W. Nemitz, S. Schweitzer, F. P. Wenzl, and C. Sommer, “Smart freeform optics solution for an extremely thin direct-lit application,” Proc. SPIE 9889, 988911 (2016).
[Crossref]

Park, J. H.

J. Cho, J. H. Park, J. K. Kim, and E. F. Schubert, “White light-emitting diodes: history, progress, and future,” Laser Photonics Rev. 11(2), 1600147 (2017).
[Crossref]

Qin, Z.

Rao, W.

J. Yan, D. Li, Z. Wang, and W. Rao, “An iterative method for the uniformity improvement of edge-lit backlight,” Adv. Optoelectron. 2016, 1–5 (2016).
[Crossref]

Reil, F.

L. Kuna, C. Leiner, W. Nemitz, F. Reil, P. Hartmann, F.-P. Wenzl, and C. Sommer, “Optical design of freeform micro-optical elements and their fabrication combining maskless laser direct write lithography and replication by imprinting,” J. Photon. Energy. 7(1), 016002 (2017).
[Crossref]

C. Leiner, W. Nemitz, S. Schweitzer, F. P. Wenzl, L. Kuna, F. Reil, P. Hartmann, and C. Sommer, “Thin direct-lit application for general lighting realized by freeform micro-optical elements,” Proc. SPIE 9955, 99550E (2016).
[Crossref]

Schubert, E. F.

J. Cho, J. H. Park, J. K. Kim, and E. F. Schubert, “White light-emitting diodes: history, progress, and future,” Laser Photonics Rev. 11(2), 1600147 (2017).
[Crossref]

Schweitzer, S.

C. Leiner, W. Nemitz, S. Schweitzer, F. P. Wenzl, L. Kuna, F. Reil, P. Hartmann, and C. Sommer, “Thin direct-lit application for general lighting realized by freeform micro-optical elements,” Proc. SPIE 9955, 99550E (2016).
[Crossref]

C. Leiner, W. Nemitz, S. Schweitzer, F. P. Wenzl, and C. Sommer, “Smart freeform optics solution for an extremely thin direct-lit application,” Proc. SPIE 9889, 988911 (2016).
[Crossref]

Shin, M. H.

M. H. Shin, J. Y. Lee, H. R. Moon, and Y. J. Kim, “Proposal and design of hybrid light guide plate based on aspheric concave surface and micropatterns to improve illuminance and color uniformity for LED display,” Jpn. J. Appl. Phys. 53, 8S2 (2014).

Sommer, C.

L. Kuna, C. Leiner, W. Nemitz, F. Reil, P. Hartmann, F.-P. Wenzl, and C. Sommer, “Optical design of freeform micro-optical elements and their fabrication combining maskless laser direct write lithography and replication by imprinting,” J. Photon. Energy. 7(1), 016002 (2017).
[Crossref]

C. Leiner, W. Nemitz, S. Schweitzer, F. P. Wenzl, L. Kuna, F. Reil, P. Hartmann, and C. Sommer, “Thin direct-lit application for general lighting realized by freeform micro-optical elements,” Proc. SPIE 9955, 99550E (2016).
[Crossref]

C. Leiner, W. Nemitz, S. Schweitzer, F. P. Wenzl, and C. Sommer, “Smart freeform optics solution for an extremely thin direct-lit application,” Proc. SPIE 9889, 988911 (2016).
[Crossref]

Teng, Y.-T.

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

Tzonchev, R. I.

Wang, K.

Wang, Z.

J. Yan, D. Li, Z. Wang, and W. Rao, “An iterative method for the uniformity improvement of edge-lit backlight,” Adv. Optoelectron. 2016, 1–5 (2016).
[Crossref]

Weckenmann, A.

F. Z. Fang, X. D. Zhang, A. Weckenmann, G. X. Zhang, and C. Evans, “Manufacturing and measurement of freeform optics,” CIRP Ann. Manuf. Technol. 62(2), 823–846 (2013).
[Crossref]

Wenzl, F. P.

C. Leiner, W. Nemitz, S. Schweitzer, F. P. Wenzl, and C. Sommer, “Smart freeform optics solution for an extremely thin direct-lit application,” Proc. SPIE 9889, 988911 (2016).
[Crossref]

C. Leiner, W. Nemitz, S. Schweitzer, F. P. Wenzl, L. Kuna, F. Reil, P. Hartmann, and C. Sommer, “Thin direct-lit application for general lighting realized by freeform micro-optical elements,” Proc. SPIE 9955, 99550E (2016).
[Crossref]

Wenzl, F.-P.

L. Kuna, C. Leiner, W. Nemitz, F. Reil, P. Hartmann, F.-P. Wenzl, and C. Sommer, “Optical design of freeform micro-optical elements and their fabrication combining maskless laser direct write lithography and replication by imprinting,” J. Photon. Energy. 7(1), 016002 (2017).
[Crossref]

Whang, A. J.-W.

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

Wu, D.

Wu, H.

H. Wu, X. Zhang, and P. Ge, “Double freeform surfaces lens design for LED uniform illumination with high distance–height ratio,” Opt. Laser Technol. 73, 166–172 (2015).
[Crossref]

Xie, B.

Yan, J.

J. Yan, D. Li, Z. Wang, and W. Rao, “An iterative method for the uniformity improvement of edge-lit backlight,” Adv. Optoelectron. 2016, 1–5 (2016).
[Crossref]

Ye, Z. T.

Yi, A. Y.

L. Li and A. Y. Yi, “Design and fabrication of a freeform microlens array for uniform beam shaping,” Microsyst. Technol. 17(12), 1713–1720 (2011).
[Crossref]

Yu, X.

Zhang, G. X.

F. Z. Fang, X. D. Zhang, A. Weckenmann, G. X. Zhang, and C. Evans, “Manufacturing and measurement of freeform optics,” CIRP Ann. Manuf. Technol. 62(2), 823–846 (2013).
[Crossref]

Zhang, N.

F. Fang, N. Zhang, and X. Zhang, “Precision injection molding of freeform optics,” Adv. Opt. Technol. 5, 303–324 (2016).

Zhang, X.

F. Fang, N. Zhang, and X. Zhang, “Precision injection molding of freeform optics,” Adv. Opt. Technol. 5, 303–324 (2016).

H. Wu, X. Zhang, and P. Ge, “Double freeform surfaces lens design for LED uniform illumination with high distance–height ratio,” Opt. Laser Technol. 73, 166–172 (2015).
[Crossref]

Zhang, X. D.

F. Z. Fang, X. D. Zhang, A. Weckenmann, G. X. Zhang, and C. Evans, “Manufacturing and measurement of freeform optics,” CIRP Ann. Manuf. Technol. 62(2), 823–846 (2013).
[Crossref]

Adv. Opt. Technol. (1)

F. Fang, N. Zhang, and X. Zhang, “Precision injection molding of freeform optics,” Adv. Opt. Technol. 5, 303–324 (2016).

Adv. Optoelectron. (1)

J. Yan, D. Li, Z. Wang, and W. Rao, “An iterative method for the uniformity improvement of edge-lit backlight,” Adv. Optoelectron. 2016, 1–5 (2016).
[Crossref]

Appl. Opt. (3)

CIRP Ann. Manuf. Technol. (1)

F. Z. Fang, X. D. Zhang, A. Weckenmann, G. X. Zhang, and C. Evans, “Manufacturing and measurement of freeform optics,” CIRP Ann. Manuf. Technol. 62(2), 823–846 (2013).
[Crossref]

J. Disp. Technol. (1)

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

J. Photon. Energy. (1)

L. Kuna, C. Leiner, W. Nemitz, F. Reil, P. Hartmann, F.-P. Wenzl, and C. Sommer, “Optical design of freeform micro-optical elements and their fabrication combining maskless laser direct write lithography and replication by imprinting,” J. Photon. Energy. 7(1), 016002 (2017).
[Crossref]

Jpn. J. Appl. Phys. (1)

M. H. Shin, J. Y. Lee, H. R. Moon, and Y. J. Kim, “Proposal and design of hybrid light guide plate based on aspheric concave surface and micropatterns to improve illuminance and color uniformity for LED display,” Jpn. J. Appl. Phys. 53, 8S2 (2014).

Laser Photonics Rev. (1)

J. Cho, J. H. Park, J. K. Kim, and E. F. Schubert, “White light-emitting diodes: history, progress, and future,” Laser Photonics Rev. 11(2), 1600147 (2017).
[Crossref]

Microsyst. Technol. (1)

L. Li and A. Y. Yi, “Design and fabrication of a freeform microlens array for uniform beam shaping,” Microsyst. Technol. 17(12), 1713–1720 (2011).
[Crossref]

Opt. Express (1)

Opt. Laser Technol. (1)

H. Wu, X. Zhang, and P. Ge, “Double freeform surfaces lens design for LED uniform illumination with high distance–height ratio,” Opt. Laser Technol. 73, 166–172 (2015).
[Crossref]

Opt. Photonics News (1)

Y. Narukawa, “White-light LEDS,” Opt. Photonics News 15(4), 24 (2004).
[Crossref]

Proc. SPIE (3)

C. Leiner, W. Nemitz, S. Schweitzer, F. P. Wenzl, and C. Sommer, “Smart freeform optics solution for an extremely thin direct-lit application,” Proc. SPIE 9889, 988911 (2016).
[Crossref]

C. Leiner, W. Nemitz, S. Schweitzer, F. P. Wenzl, L. Kuna, F. Reil, P. Hartmann, and C. Sommer, “Thin direct-lit application for general lighting realized by freeform micro-optical elements,” Proc. SPIE 9955, 99550E (2016).
[Crossref]

T. Blalock, K. Medicus, and J. DeGroote Nelson, “Fabrication of freeform optics,” Proc. SPIE 9575, 95750H (2015).

Other (1)

R. Hu, H. Zheng, C. Ji, S. Liu, and X. Luo, “A method to design freeform lens for uniform illumination in direct-lit led backlight with high distance-height ratio,” ICEPT-HDP 2012 Proc. - 2012 13th Int. Conf. Electron. Packag. Technol. High Density Packag. 1474–1478 (2012).

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Figures (9)

Fig. 1
Fig. 1 Schematic illustration of relationships between the radiant intensity distribution IS(θ) of the source and the transmitted radiant intensity distribution IL(θ) of the FF element.

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Fig. 2
Fig. 2 Plot of the functions for the modified angles θL’ in dependence of θS for θS_MAX = 63.43°, V = 0.2 and for different DHR values (1, 2, 3, 3.41 and 4).

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Fig. 3
Fig. 3 Plot of the slopes for the top side (a) and the the bottom side (c) placed FF-MOEs and their corresponding FF curvatures (b), (d).

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Fig. 4
Fig. 4 Schematic illustration of the transformation algorithm, which generates “artificial edges” in the shape of the FF curvature in order to limit the maximal thickness of the FF-MOE.

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Fig. 5
Fig. 5 Plot of the calculated FF curvature (red) arranged on the bottom side of a PMMA plate (Bottom side of the PMMA plate in green, top side in blue) after applying the sequential pointwise FF design procedure. The light source is located at z = 0 and is centrically placed beneath the FF-MOE. The target plane is located at z = 10.

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Fig. 6
Fig. 6 a. ,b,c,d) Top side pictures of the different components of the direct lit luminaire demonstrator box. (a) Bottom part of the box, including the circuit board with 14 LEDs arranged in a hexagonal array. b) Spacer component between source plane and FF plane of the box including the PMMA plate with the FF-MOEs (c) Spacer component between FF plane and target plane of the box and the diffusing film. (d) Top side of the Box. (e) Schematic illustration of the arrangement of the different components shown in (a-d)

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Fig. 7
Fig. 7 Simulated irradiance distribution within the target area for different simulation settings: a) Simulation with FF-MOE b) Simulation without FF-MOE, c) Simulation results considering only rays which were refracted at the artificial edges of the FF MOE, d) Simulation result without considering rays which were refracted at the artificial edges.

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Fig. 8
Fig. 8 Simulated irradiance distribution on the bottom side of the diffusing film without considering the effects caused by the artificial edges. a) Irradiance distribution without FF-MOEs, b) Irradiance distribution with FF-MOEs.

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Fig. 9
Fig. 9 Photos of the illuminated top surface of the direct-lit luminaire box system: a) with PMMA plate and without the FF-MOEs) PMMA plate containing the FF-MOEs.

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Equations (5)

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k S ∫ 0 2π dφ ∫ 0 θ S_max I S (θ)sinθdθ = k L ∫ 0 2π dφ ∫ 0 θ L_max I L (θ)sinθdθ
k S ∫ 0 2π dφ ∫ 0 θ S I S (θ)sinθdθ = k L ∫ 0 2π dφ ∫ 0 θ L I L (θ)sinθdθ
θ L = tan −1 ( sin( θ S ) sin( θ S_MAX ) DHR 2 )
θ L '= cos −1 ( (1−V) ( tan( θ L )−Vtan( θ S ) ) 2 + ( 1−V ) 2 )
CV(RMSE)= 1 MN ∑ m=1 M ∑ n=1 N (I( x m , x n )− I Mean ) 2 I Mean