Abstract

We report on a novel speckle reduction scheme using microlens arrays as screen material for application in laser-based projection systems. The scheme is based on properly adjusting the coherence properties on the screen: when the coherence area on the microlens-array screen is smaller than the microlens footprint, there is no interference between the fields emitted by the different microlenses and as a result no speckle is formed. We measured and modelled the speckle properties of microlens arrays with regular and irregular structure and lens sizes, and also a paper screen for comparison. In the experiments, we tune the laser beam’s spatial coherence by sending it through a rotating diffuser. We show the amount of speckle reduction that can be achieved, which mechanisms influence the observed speckle contrast and we discuss the limitations due to increased non-uniformity in the projected image.

© 2017 Optical Society of America

Full Article  |  PDF Article
OSA Recommended Articles
Analysis of laser speckle reduction utilizing microlens-array-based projection screen

Qianli Ma and Chang-Qing Xu
J. Opt. Soc. Am. A 34(9) 1595-1601 (2017)

Laser speckle reduction via colloidal-dispersion-filled projection screens

Falko Riechert, Georg Bastian, and Uli Lemmer
Appl. Opt. 48(19) 3742-3749 (2009)

Speckle reduction mechanism in laser rear projection displays using a small moving diffuser

Yuhei Kuratomi, Kazuo Sekiya, Hiroaki Satoh, Tatsuhiro Tomiyama, Tohru Kawakami, Baku Katagiri, Yoshito Suzuki, and Tatsuo Uchida
J. Opt. Soc. Am. A 27(8) 1812-1817 (2010)

References

  • View by:
  • |
  • |
  • |

  1. B. Beck, “Lasers light up the silver screen,” IEEE Spectrum 51(3), 32–39 (2014).
    [Crossref]
  2. G. Derra, H. Moench, E. Fischer, H. Giese, U. Hechtfischer, G. Heusler, A. Koerber, U. Niemann, F.C. Noertemann, P. Pekarski, J. Pollmann-Retsch, A. Ritz, and U. Weichmann, “UPH lamp systems for projection applications,” J. Phys. D: Appl. Phys. 38(17), 2995–3010 (2005).
    [Crossref]
  3. K. V. Chellappan, E. Erden, and H. Urey, “Laser-based displays: a review,” Appl. Opt. 49(25), F79–F98 (2010).
    [Crossref] [PubMed]
  4. J. W. Goodman, Speckle Phenomena in Optics: Theory and Applications (W. H. Freeman, 2010).
  5. J. I. Trisnadi, “Speckle contrast reduction in laser projection displays,” Proc. SPIE 4657, 131 (2002).
    [Crossref]
  6. Z. Tong and X. Chen, “Speckle contrast for superposed speckle patterns created by rotating the orientation of laser polarization,” J. Opt. Soc. Am. A 29(10), 2074–2079 (2012).
    [Crossref]
  7. A. Furukawa, N. Ohse, Y. Sato, D. Imanishi, K. Wakabayashi, S. Ito, K. Tamamura, and S. Hirata, “Effective speckle reduction in laser projection displays,” Proc. SPIE 6911, 69110T (2008).
    [Crossref]
  8. S. Kubota and J. W. Goodman, “Very efficient speckle contrast reduction realized by moving diffuser device,” Appl. Optics 49(23), 4385–4391(2010).
    [Crossref]
  9. M.N. Akram, Z. Tong, G. Ouyang, X. Chen, and V. Kartashov, “Laser speckle reduction due to spatial and angular diversity introduced by fast scanning micromirror,” Appl. Opt. 49(17), 3297–3304 (2010).
    [Crossref] [PubMed]
  10. C. Y. Chen, W. C. Su, C. H. Lin, M. D. Ke, Q. L. Deng, and K. Y. Chiu, “Reduction of speckles and distortion in projection system by using a rotating diffuser,” Opt. Rev. 19(6), 440–443 (2012).
    [Crossref]
  11. G. Verschaffelt, S. Roelandt, Y. Meuret, W. Van den Broeck, K. Kilpi, B. Lievens, A. Jacobs, P. Janssens, and H. Thienpont, “Speckle disturbance limit in laser-based cinema projection systems,” Sci. Rep. 5, 14105 (2015).
    [Crossref] [PubMed]
  12. S. Roelandt, Y. Meuret, A. Jacobs, K. Willaert, P. Janssens, H. Thienpont, and G. Verschaffelt, “Human speckle perception threshold for still images from a laser projection system,” Opt. Express 22(20), 23965–23979 (2014).
    [Crossref] [PubMed]
  13. M.K. Hedili, Kivanc, M.O. Freeman, and H. Urey, “Transmission characteristics of a bidirectional transparent screen based on reflective microlenses,” Opt. Express 21(21), 24636–24646 (2013).
    [Crossref] [PubMed]
  14. L. Mandel and E. Wolf, Optical Coherence and Quantum Optics (Cambridge University, 1995).
    [Crossref]
  15. J. W. Goodman, Introduction to Fourier Optics (Roberts and Company, 2004).
  16. F. Riechert, Speckle Reduction in Projection Systems, Doctoral dissertation, Karlsruhe Institute of Technology, 2009.

2015 (1)

G. Verschaffelt, S. Roelandt, Y. Meuret, W. Van den Broeck, K. Kilpi, B. Lievens, A. Jacobs, P. Janssens, and H. Thienpont, “Speckle disturbance limit in laser-based cinema projection systems,” Sci. Rep. 5, 14105 (2015).
[Crossref] [PubMed]

2014 (2)

2013 (1)

2012 (2)

C. Y. Chen, W. C. Su, C. H. Lin, M. D. Ke, Q. L. Deng, and K. Y. Chiu, “Reduction of speckles and distortion in projection system by using a rotating diffuser,” Opt. Rev. 19(6), 440–443 (2012).
[Crossref]

Z. Tong and X. Chen, “Speckle contrast for superposed speckle patterns created by rotating the orientation of laser polarization,” J. Opt. Soc. Am. A 29(10), 2074–2079 (2012).
[Crossref]

2010 (3)

2008 (1)

A. Furukawa, N. Ohse, Y. Sato, D. Imanishi, K. Wakabayashi, S. Ito, K. Tamamura, and S. Hirata, “Effective speckle reduction in laser projection displays,” Proc. SPIE 6911, 69110T (2008).
[Crossref]

2005 (1)

G. Derra, H. Moench, E. Fischer, H. Giese, U. Hechtfischer, G. Heusler, A. Koerber, U. Niemann, F.C. Noertemann, P. Pekarski, J. Pollmann-Retsch, A. Ritz, and U. Weichmann, “UPH lamp systems for projection applications,” J. Phys. D: Appl. Phys. 38(17), 2995–3010 (2005).
[Crossref]

2002 (1)

J. I. Trisnadi, “Speckle contrast reduction in laser projection displays,” Proc. SPIE 4657, 131 (2002).
[Crossref]

Akram, M.N.

Beck, B.

B. Beck, “Lasers light up the silver screen,” IEEE Spectrum 51(3), 32–39 (2014).
[Crossref]

Chellappan, K. V.

Chen, C. Y.

C. Y. Chen, W. C. Su, C. H. Lin, M. D. Ke, Q. L. Deng, and K. Y. Chiu, “Reduction of speckles and distortion in projection system by using a rotating diffuser,” Opt. Rev. 19(6), 440–443 (2012).
[Crossref]

Chen, X.

Chiu, K. Y.

C. Y. Chen, W. C. Su, C. H. Lin, M. D. Ke, Q. L. Deng, and K. Y. Chiu, “Reduction of speckles and distortion in projection system by using a rotating diffuser,” Opt. Rev. 19(6), 440–443 (2012).
[Crossref]

Deng, Q. L.

C. Y. Chen, W. C. Su, C. H. Lin, M. D. Ke, Q. L. Deng, and K. Y. Chiu, “Reduction of speckles and distortion in projection system by using a rotating diffuser,” Opt. Rev. 19(6), 440–443 (2012).
[Crossref]

Derra, G.

G. Derra, H. Moench, E. Fischer, H. Giese, U. Hechtfischer, G. Heusler, A. Koerber, U. Niemann, F.C. Noertemann, P. Pekarski, J. Pollmann-Retsch, A. Ritz, and U. Weichmann, “UPH lamp systems for projection applications,” J. Phys. D: Appl. Phys. 38(17), 2995–3010 (2005).
[Crossref]

Erden, E.

Fischer, E.

G. Derra, H. Moench, E. Fischer, H. Giese, U. Hechtfischer, G. Heusler, A. Koerber, U. Niemann, F.C. Noertemann, P. Pekarski, J. Pollmann-Retsch, A. Ritz, and U. Weichmann, “UPH lamp systems for projection applications,” J. Phys. D: Appl. Phys. 38(17), 2995–3010 (2005).
[Crossref]

Freeman, M.O.

Furukawa, A.

A. Furukawa, N. Ohse, Y. Sato, D. Imanishi, K. Wakabayashi, S. Ito, K. Tamamura, and S. Hirata, “Effective speckle reduction in laser projection displays,” Proc. SPIE 6911, 69110T (2008).
[Crossref]

Giese, H.

G. Derra, H. Moench, E. Fischer, H. Giese, U. Hechtfischer, G. Heusler, A. Koerber, U. Niemann, F.C. Noertemann, P. Pekarski, J. Pollmann-Retsch, A. Ritz, and U. Weichmann, “UPH lamp systems for projection applications,” J. Phys. D: Appl. Phys. 38(17), 2995–3010 (2005).
[Crossref]

Goodman, J. W.

S. Kubota and J. W. Goodman, “Very efficient speckle contrast reduction realized by moving diffuser device,” Appl. Optics 49(23), 4385–4391(2010).
[Crossref]

J. W. Goodman, Speckle Phenomena in Optics: Theory and Applications (W. H. Freeman, 2010).

J. W. Goodman, Introduction to Fourier Optics (Roberts and Company, 2004).

Hechtfischer, U.

G. Derra, H. Moench, E. Fischer, H. Giese, U. Hechtfischer, G. Heusler, A. Koerber, U. Niemann, F.C. Noertemann, P. Pekarski, J. Pollmann-Retsch, A. Ritz, and U. Weichmann, “UPH lamp systems for projection applications,” J. Phys. D: Appl. Phys. 38(17), 2995–3010 (2005).
[Crossref]

Hedili, M.K.

Heusler, G.

G. Derra, H. Moench, E. Fischer, H. Giese, U. Hechtfischer, G. Heusler, A. Koerber, U. Niemann, F.C. Noertemann, P. Pekarski, J. Pollmann-Retsch, A. Ritz, and U. Weichmann, “UPH lamp systems for projection applications,” J. Phys. D: Appl. Phys. 38(17), 2995–3010 (2005).
[Crossref]

Hirata, S.

A. Furukawa, N. Ohse, Y. Sato, D. Imanishi, K. Wakabayashi, S. Ito, K. Tamamura, and S. Hirata, “Effective speckle reduction in laser projection displays,” Proc. SPIE 6911, 69110T (2008).
[Crossref]

Imanishi, D.

A. Furukawa, N. Ohse, Y. Sato, D. Imanishi, K. Wakabayashi, S. Ito, K. Tamamura, and S. Hirata, “Effective speckle reduction in laser projection displays,” Proc. SPIE 6911, 69110T (2008).
[Crossref]

Ito, S.

A. Furukawa, N. Ohse, Y. Sato, D. Imanishi, K. Wakabayashi, S. Ito, K. Tamamura, and S. Hirata, “Effective speckle reduction in laser projection displays,” Proc. SPIE 6911, 69110T (2008).
[Crossref]

Jacobs, A.

G. Verschaffelt, S. Roelandt, Y. Meuret, W. Van den Broeck, K. Kilpi, B. Lievens, A. Jacobs, P. Janssens, and H. Thienpont, “Speckle disturbance limit in laser-based cinema projection systems,” Sci. Rep. 5, 14105 (2015).
[Crossref] [PubMed]

S. Roelandt, Y. Meuret, A. Jacobs, K. Willaert, P. Janssens, H. Thienpont, and G. Verschaffelt, “Human speckle perception threshold for still images from a laser projection system,” Opt. Express 22(20), 23965–23979 (2014).
[Crossref] [PubMed]

Janssens, P.

G. Verschaffelt, S. Roelandt, Y. Meuret, W. Van den Broeck, K. Kilpi, B. Lievens, A. Jacobs, P. Janssens, and H. Thienpont, “Speckle disturbance limit in laser-based cinema projection systems,” Sci. Rep. 5, 14105 (2015).
[Crossref] [PubMed]

S. Roelandt, Y. Meuret, A. Jacobs, K. Willaert, P. Janssens, H. Thienpont, and G. Verschaffelt, “Human speckle perception threshold for still images from a laser projection system,” Opt. Express 22(20), 23965–23979 (2014).
[Crossref] [PubMed]

Kartashov, V.

Ke, M. D.

C. Y. Chen, W. C. Su, C. H. Lin, M. D. Ke, Q. L. Deng, and K. Y. Chiu, “Reduction of speckles and distortion in projection system by using a rotating diffuser,” Opt. Rev. 19(6), 440–443 (2012).
[Crossref]

Kilpi, K.

G. Verschaffelt, S. Roelandt, Y. Meuret, W. Van den Broeck, K. Kilpi, B. Lievens, A. Jacobs, P. Janssens, and H. Thienpont, “Speckle disturbance limit in laser-based cinema projection systems,” Sci. Rep. 5, 14105 (2015).
[Crossref] [PubMed]

Kivanc,

Koerber, A.

G. Derra, H. Moench, E. Fischer, H. Giese, U. Hechtfischer, G. Heusler, A. Koerber, U. Niemann, F.C. Noertemann, P. Pekarski, J. Pollmann-Retsch, A. Ritz, and U. Weichmann, “UPH lamp systems for projection applications,” J. Phys. D: Appl. Phys. 38(17), 2995–3010 (2005).
[Crossref]

Kubota, S.

S. Kubota and J. W. Goodman, “Very efficient speckle contrast reduction realized by moving diffuser device,” Appl. Optics 49(23), 4385–4391(2010).
[Crossref]

Lievens, B.

G. Verschaffelt, S. Roelandt, Y. Meuret, W. Van den Broeck, K. Kilpi, B. Lievens, A. Jacobs, P. Janssens, and H. Thienpont, “Speckle disturbance limit in laser-based cinema projection systems,” Sci. Rep. 5, 14105 (2015).
[Crossref] [PubMed]

Lin, C. H.

C. Y. Chen, W. C. Su, C. H. Lin, M. D. Ke, Q. L. Deng, and K. Y. Chiu, “Reduction of speckles and distortion in projection system by using a rotating diffuser,” Opt. Rev. 19(6), 440–443 (2012).
[Crossref]

Mandel, L.

L. Mandel and E. Wolf, Optical Coherence and Quantum Optics (Cambridge University, 1995).
[Crossref]

Meuret, Y.

G. Verschaffelt, S. Roelandt, Y. Meuret, W. Van den Broeck, K. Kilpi, B. Lievens, A. Jacobs, P. Janssens, and H. Thienpont, “Speckle disturbance limit in laser-based cinema projection systems,” Sci. Rep. 5, 14105 (2015).
[Crossref] [PubMed]

S. Roelandt, Y. Meuret, A. Jacobs, K. Willaert, P. Janssens, H. Thienpont, and G. Verschaffelt, “Human speckle perception threshold for still images from a laser projection system,” Opt. Express 22(20), 23965–23979 (2014).
[Crossref] [PubMed]

Moench, H.

G. Derra, H. Moench, E. Fischer, H. Giese, U. Hechtfischer, G. Heusler, A. Koerber, U. Niemann, F.C. Noertemann, P. Pekarski, J. Pollmann-Retsch, A. Ritz, and U. Weichmann, “UPH lamp systems for projection applications,” J. Phys. D: Appl. Phys. 38(17), 2995–3010 (2005).
[Crossref]

Niemann, U.

G. Derra, H. Moench, E. Fischer, H. Giese, U. Hechtfischer, G. Heusler, A. Koerber, U. Niemann, F.C. Noertemann, P. Pekarski, J. Pollmann-Retsch, A. Ritz, and U. Weichmann, “UPH lamp systems for projection applications,” J. Phys. D: Appl. Phys. 38(17), 2995–3010 (2005).
[Crossref]

Noertemann, F.C.

G. Derra, H. Moench, E. Fischer, H. Giese, U. Hechtfischer, G. Heusler, A. Koerber, U. Niemann, F.C. Noertemann, P. Pekarski, J. Pollmann-Retsch, A. Ritz, and U. Weichmann, “UPH lamp systems for projection applications,” J. Phys. D: Appl. Phys. 38(17), 2995–3010 (2005).
[Crossref]

Ohse, N.

A. Furukawa, N. Ohse, Y. Sato, D. Imanishi, K. Wakabayashi, S. Ito, K. Tamamura, and S. Hirata, “Effective speckle reduction in laser projection displays,” Proc. SPIE 6911, 69110T (2008).
[Crossref]

Ouyang, G.

Pekarski, P.

G. Derra, H. Moench, E. Fischer, H. Giese, U. Hechtfischer, G. Heusler, A. Koerber, U. Niemann, F.C. Noertemann, P. Pekarski, J. Pollmann-Retsch, A. Ritz, and U. Weichmann, “UPH lamp systems for projection applications,” J. Phys. D: Appl. Phys. 38(17), 2995–3010 (2005).
[Crossref]

Pollmann-Retsch, J.

G. Derra, H. Moench, E. Fischer, H. Giese, U. Hechtfischer, G. Heusler, A. Koerber, U. Niemann, F.C. Noertemann, P. Pekarski, J. Pollmann-Retsch, A. Ritz, and U. Weichmann, “UPH lamp systems for projection applications,” J. Phys. D: Appl. Phys. 38(17), 2995–3010 (2005).
[Crossref]

Riechert, F.

F. Riechert, Speckle Reduction in Projection Systems, Doctoral dissertation, Karlsruhe Institute of Technology, 2009.

Ritz, A.

G. Derra, H. Moench, E. Fischer, H. Giese, U. Hechtfischer, G. Heusler, A. Koerber, U. Niemann, F.C. Noertemann, P. Pekarski, J. Pollmann-Retsch, A. Ritz, and U. Weichmann, “UPH lamp systems for projection applications,” J. Phys. D: Appl. Phys. 38(17), 2995–3010 (2005).
[Crossref]

Roelandt, S.

G. Verschaffelt, S. Roelandt, Y. Meuret, W. Van den Broeck, K. Kilpi, B. Lievens, A. Jacobs, P. Janssens, and H. Thienpont, “Speckle disturbance limit in laser-based cinema projection systems,” Sci. Rep. 5, 14105 (2015).
[Crossref] [PubMed]

S. Roelandt, Y. Meuret, A. Jacobs, K. Willaert, P. Janssens, H. Thienpont, and G. Verschaffelt, “Human speckle perception threshold for still images from a laser projection system,” Opt. Express 22(20), 23965–23979 (2014).
[Crossref] [PubMed]

Sato, Y.

A. Furukawa, N. Ohse, Y. Sato, D. Imanishi, K. Wakabayashi, S. Ito, K. Tamamura, and S. Hirata, “Effective speckle reduction in laser projection displays,” Proc. SPIE 6911, 69110T (2008).
[Crossref]

Su, W. C.

C. Y. Chen, W. C. Su, C. H. Lin, M. D. Ke, Q. L. Deng, and K. Y. Chiu, “Reduction of speckles and distortion in projection system by using a rotating diffuser,” Opt. Rev. 19(6), 440–443 (2012).
[Crossref]

Tamamura, K.

A. Furukawa, N. Ohse, Y. Sato, D. Imanishi, K. Wakabayashi, S. Ito, K. Tamamura, and S. Hirata, “Effective speckle reduction in laser projection displays,” Proc. SPIE 6911, 69110T (2008).
[Crossref]

Thienpont, H.

G. Verschaffelt, S. Roelandt, Y. Meuret, W. Van den Broeck, K. Kilpi, B. Lievens, A. Jacobs, P. Janssens, and H. Thienpont, “Speckle disturbance limit in laser-based cinema projection systems,” Sci. Rep. 5, 14105 (2015).
[Crossref] [PubMed]

S. Roelandt, Y. Meuret, A. Jacobs, K. Willaert, P. Janssens, H. Thienpont, and G. Verschaffelt, “Human speckle perception threshold for still images from a laser projection system,” Opt. Express 22(20), 23965–23979 (2014).
[Crossref] [PubMed]

Tong, Z.

Trisnadi, J. I.

J. I. Trisnadi, “Speckle contrast reduction in laser projection displays,” Proc. SPIE 4657, 131 (2002).
[Crossref]

Urey, H.

Van den Broeck, W.

G. Verschaffelt, S. Roelandt, Y. Meuret, W. Van den Broeck, K. Kilpi, B. Lievens, A. Jacobs, P. Janssens, and H. Thienpont, “Speckle disturbance limit in laser-based cinema projection systems,” Sci. Rep. 5, 14105 (2015).
[Crossref] [PubMed]

Verschaffelt, G.

G. Verschaffelt, S. Roelandt, Y. Meuret, W. Van den Broeck, K. Kilpi, B. Lievens, A. Jacobs, P. Janssens, and H. Thienpont, “Speckle disturbance limit in laser-based cinema projection systems,” Sci. Rep. 5, 14105 (2015).
[Crossref] [PubMed]

S. Roelandt, Y. Meuret, A. Jacobs, K. Willaert, P. Janssens, H. Thienpont, and G. Verschaffelt, “Human speckle perception threshold for still images from a laser projection system,” Opt. Express 22(20), 23965–23979 (2014).
[Crossref] [PubMed]

Wakabayashi, K.

A. Furukawa, N. Ohse, Y. Sato, D. Imanishi, K. Wakabayashi, S. Ito, K. Tamamura, and S. Hirata, “Effective speckle reduction in laser projection displays,” Proc. SPIE 6911, 69110T (2008).
[Crossref]

Weichmann, U.

G. Derra, H. Moench, E. Fischer, H. Giese, U. Hechtfischer, G. Heusler, A. Koerber, U. Niemann, F.C. Noertemann, P. Pekarski, J. Pollmann-Retsch, A. Ritz, and U. Weichmann, “UPH lamp systems for projection applications,” J. Phys. D: Appl. Phys. 38(17), 2995–3010 (2005).
[Crossref]

Willaert, K.

Wolf, E.

L. Mandel and E. Wolf, Optical Coherence and Quantum Optics (Cambridge University, 1995).
[Crossref]

Appl. Opt. (2)

Appl. Optics (1)

S. Kubota and J. W. Goodman, “Very efficient speckle contrast reduction realized by moving diffuser device,” Appl. Optics 49(23), 4385–4391(2010).
[Crossref]

IEEE Spectrum (1)

B. Beck, “Lasers light up the silver screen,” IEEE Spectrum 51(3), 32–39 (2014).
[Crossref]

J. Opt. Soc. Am. A (1)

J. Phys. D: Appl. Phys. (1)

G. Derra, H. Moench, E. Fischer, H. Giese, U. Hechtfischer, G. Heusler, A. Koerber, U. Niemann, F.C. Noertemann, P. Pekarski, J. Pollmann-Retsch, A. Ritz, and U. Weichmann, “UPH lamp systems for projection applications,” J. Phys. D: Appl. Phys. 38(17), 2995–3010 (2005).
[Crossref]

Opt. Express (2)

Opt. Rev. (1)

C. Y. Chen, W. C. Su, C. H. Lin, M. D. Ke, Q. L. Deng, and K. Y. Chiu, “Reduction of speckles and distortion in projection system by using a rotating diffuser,” Opt. Rev. 19(6), 440–443 (2012).
[Crossref]

Proc. SPIE (2)

A. Furukawa, N. Ohse, Y. Sato, D. Imanishi, K. Wakabayashi, S. Ito, K. Tamamura, and S. Hirata, “Effective speckle reduction in laser projection displays,” Proc. SPIE 6911, 69110T (2008).
[Crossref]

J. I. Trisnadi, “Speckle contrast reduction in laser projection displays,” Proc. SPIE 4657, 131 (2002).
[Crossref]

Sci. Rep. (1)

G. Verschaffelt, S. Roelandt, Y. Meuret, W. Van den Broeck, K. Kilpi, B. Lievens, A. Jacobs, P. Janssens, and H. Thienpont, “Speckle disturbance limit in laser-based cinema projection systems,” Sci. Rep. 5, 14105 (2015).
[Crossref] [PubMed]

Other (4)

L. Mandel and E. Wolf, Optical Coherence and Quantum Optics (Cambridge University, 1995).
[Crossref]

J. W. Goodman, Introduction to Fourier Optics (Roberts and Company, 2004).

F. Riechert, Speckle Reduction in Projection Systems, Doctoral dissertation, Karlsruhe Institute of Technology, 2009.

J. W. Goodman, Speckle Phenomena in Optics: Theory and Applications (W. H. Freeman, 2010).

Cited By

OSA participates in Crossref's Cited-By Linking service. Citing articles from OSA journals and other participating publishers are listed here.

Alert me when this article is cited.


Figures (11)

Fig. 1
Fig. 1 Schematic representation of speckle contrast reduction in laser projection systems using a microlens array as screen material.
Fig. 2
Fig. 2 Schematic representation of the speckle measurement setup. From left to right: diode-pumped solid state laser, (L1) single lens with focal length f = 50mm, (RD) ground plate rotating diffuser, (P) polarizer, (S) screen, (ND) neutral density filter, (L2) Nikon compound imaging lens and CCD sensor
Fig. 3
Fig. 3 Recorded and processed images corresponding to consecutive steps in the speckle contrast extraction procedure explained in Section 2.
Fig. 4
Fig. 4 Speckle contrast measurement results on irregular MLA screen, for varying sizes of the on-screen coherence area and for 3 different values of the imaging resolution. The two panels show the same experimental data. The horizontal axis has the ratio of the width of the on-screen coherence area Lcoh to the width of the a) microlens footprint Lfp b) resolution spot Lres.
Fig. 5
Fig. 5 Speckle contrast measurement results on regular MLA screen, for varying sizes of the on-screen coherence area and for 3 different values of the imaging resolution. The horizontal axis has the ratio of the width of the on-screen coherence area Lcoh to the width of the microlens footprint Lfp. The small markers correspond to measurements with a structured diffraction pattern in the recorded image. For these datapoints the estimated speckle contrast C is meaningless. The large markers correspond to valid speckle constrast estimates from measurements where the diffraction pattern had disappeared due to small coherence.
Fig. 6
Fig. 6 Recorded images for the irregular MLA (top row) and the regular MLA (bottom row). For both screens, from left to right, the radius of the coherence area Rcoh is equal to 19, 27, 74 and 600. The imaging system resolution is 650.
Fig. 7
Fig. 7 Speckle contrast measurement results, for varying sizes of the on-screen coherence area and for different screens, imaged with a resolution of 650. The horizontal axis has the ratio of the width of the on-screen coherence area Lcoh to the width of the resolution spot Lres.
Fig. 8
Fig. 8 Recorded images of polarization measurements on both the irregular and the regular MLA. For these experiments the screens were placed in between two polarizers. The relative angle of the two polarizers for which maximum and minimum transmission is achieved are labeled θmax and θmin, respectively. The angles θmax and θmin are 90 apart. The measurements on the irregular array show that the amount of polarization rotation is not uniform over the screen.
Fig. 9
Fig. 9 Speckle contrast versus the ratio of the width of the on-screen coherence area Lcoh to the width of the resolution spot Lres. Markers indicate speckle contrast measurements on paper (blue), and irregular MLA (red) screen, imaged with a resolution of 650μm. The full and dashed lines illustrate the corresponding model predictions, as constructed in a) Section 4.1 b) Section 4.3.
Fig. 10
Fig. 10 Comparison of the spatial coherence described by Eq. (12) with the initial model (see Section 4.1) which models partial coherence only moderately well, and the improved model (see Section 4.3) wich uses an average coherence to mimic partial coherence.
Fig. 11
Fig. 11 The size of coherence cells, in green, and the resolution spot, in blue, is the same in both figures, but the grid of coherence cells has shifted with respect to the resolution spot. Within the resolution spot on the screen we count in a) 9 complete and in b) 4 complete and 12 incomplete coherence cells.

Tables (2)

Tables Icon

Table 1 DOP and corresponding reduction factors for different screens

Tables Icon

Table 2 Screen non-uniformity for different screens and different resolutions.

Equations (15)

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

θ int = λ π γ NF and θ coh = λ π w RD
C 2 = C theor 2 + C nu 2
C 2 = ( 1 Π i R i ) 2 + C n u 2
DOP = I max I min I max + I min
R pol = 2 1 + DOP 2
δ λ = λ 2 2 σ h
N λ = Δ λ δ λ = 2 σ h Δ λ λ 2
R λ = N λ = 2 σ h Δ λ λ 2
N = A res A coh R N = L res L coh
R μ = M M 1
M = min ( A coh , A res ) A f p
γ ( r ) = exp ( r 2 2 R coh 2 )
C N = σ s I ¯ s = n = 1 N σ n 2 n = 1 N I ¯ n = C 1 n = 1 N I ¯ n 2 n = 1 N I ¯ n
R N ( a ) = n = 1 9 S n n = 1 9 S n 2 = 9 × 1 9 × 1 2 = 3 R N ( b ) = n = 1 16 S n n = 1 16 S n 2 = 4 × 1 + 8 × ( 1 / 2 ) + 4 × ( 1 / 4 ) 4 × 1 2 + 8 × ( 1 / 2 ) 2 + 4 × ( 1 / 4 ) 2 4.4
R N avg = 0 L coh 0 L coh n = 1 N S n ( x , y ) n = 1 N S n ( x , y ) 2 d x d y

Metrics