Abstract

A simple but efficient color mixing system for micro-projection display is presented in this paper, which has employed off-axis arranged LEDs and specifically designed dichroic mirrors in order to achieve higher optical efficiency and a better space utilization ratio compared with previous systems. The design method of the dual-dichroic-mirror (DDM) system is investigated both analytically and numerically. The design results are consistent with the theoretical calculation, and the advantages of the proposed DDM system are obvious. Compared with traditional systems that are commonly used in micro-projectors, the DDM system has indicated a much higher collection efficiency (up to 93.36%) with a significantly reduced size of 1.47 cc. Equipped with the DDM system, the designed micro-projector has realized an energy utilization ratio of 76.92% and an irradiance uniformity of 96.59% with an ultra-compact volume of 28.8mm×28.1mm×10mm, which is competent for embedded projection display. It is believed that such a design has good prospects in commercialized production in the future.

© 2014 Optical Society of America

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  1. D. E. Slobodin and C. Biber, “Ultraportable projector progress and prospects,” Proc. SPIE 3954, 19–26 (2000).
    [CrossRef]
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    [CrossRef]
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    [CrossRef]
  4. W. J. Cassarly, “High-brightness LEDs,” Opt. Photon. News 19(1), 18–23 (2008).
    [CrossRef]
  5. X. Zhao, Z. Fang, J. Cui, X. Zhang, and G. Mu, “Illumination system using LED sources for pocket-size projectors,” Appl. Opt. 46, 522–526 (2007).
    [CrossRef]
  6. C. L. Bruzzone, R. E. English, and D. J. W. Aastuen, “Compact high-brightness LED illumination for projection systems,” J. Soc. Inf. Disp. 17, 1043–1049 (2009).
    [CrossRef]
  7. C. Cheng and J. Chern, “Illuminance formation and color difference of mixed-color light emitting diodes in a rectangular light pipe: an analytical approach,” Appl. Opt. 47, 431–441 (2008).
    [CrossRef]
  8. Y. Meuret, B. Vangiel, F. Christiaens, and H. Thienpont, “Efficient illumination in LED-based projection systems using lenslet integrators,” Proc. SPIE 6196, 619605 (2006).
    [CrossRef]
  9. C. Peng, X. Li, P. Zhang, L. Xiong, and X. Liu, “RGB high brightness LED modules for projection display application,” J. Display Technol. 7, 448–453 (2011).
    [CrossRef]
  10. H. Murat, H. D. Smet, and D. Uypers, “Compact LED projector with tapered light pipes for moderate light output applications,” Displays 27, 117–123 (2006).
    [CrossRef]
  11. H. Murat, A. Gielen, and H. D. Smet, “Gradually tapered light pipes for illumination of LED projectors,” J. Soc. Inf. Disp. 15, 519–526 (2007).
    [CrossRef]
  12. R. Joachim and W. Alexander, “Requirements on LEDs for advanced optical systems,” Proc. SPIE 6486, 64860Z (2007).
  13. G. Harbers, S. J. Bierhuizen, and M. R. Krames, “Performance of high power light emitting diodes in display illumination applications,” J. Display Technol. 3, 98–109 (2007).
    [CrossRef]
  14. W. S. Sun, Y. C. Chiang, and C. H. Tsuei, “Optical design for the DLP pocket projector using LED light source,” Phys. Procedia 19, 301–307 (2011).
    [CrossRef]
  15. L. Tan, J. Sun, and H. S. Kwok, “A high efficiency compact size color-sequential LCOS projection engine with 100% NTSC,” SID Symp. Dig. Tech. Papers 42, 1798–1800 (2011).
    [CrossRef]
  16. A. G. Huibers and R. Grasser, “Light combiner,” U.S. patent0,251,783 (October8, 2009).
  17. E. G. Chen, P. Liu, and F. H. Yu, “Synchronized parameter optimization of the double freeform lenses illumination system used for the CF-LCoS pico-projectors,” Opt. Laser Technol. 44, 2080–2087 (2012).
    [CrossRef]
  18. S. Chen and K. Chuang, “Illumination system and projection apparatus,” U.S. patent0,291,484 (December20, 2007).
  19. Z. R. Zheng, X. Hao, and X. Liu, “Freeform surface lens for LED uniform illumination,” Appl. Opt. 48, 6627–6634 (2009).
    [CrossRef]
  20. R. Wu, L. Xu, P. Liu, Y. Zhang, Z. Zheng, H. Li, and X. Liu, “Freeform illumination design: a nonlinear boundary problem for the elliptic Monge–Ampére equation,” Opt. Lett. 38, 229–231 (2013).
    [CrossRef]
  21. J. Chen, T. Wang, K. Huang, T. Liu, M. Tsai, and C. Lin, “Freeform lens design for LED collimating illumination,” Opt. Express 20, 10984–10995 (2012).
    [CrossRef]

2013 (1)

2012 (3)

E. Buckley, “On proximity detection systems for pico-projectors,” J. Soc. Inf. Disp. 20, 297–299 (2012).
[CrossRef]

E. G. Chen, P. Liu, and F. H. Yu, “Synchronized parameter optimization of the double freeform lenses illumination system used for the CF-LCoS pico-projectors,” Opt. Laser Technol. 44, 2080–2087 (2012).
[CrossRef]

J. Chen, T. Wang, K. Huang, T. Liu, M. Tsai, and C. Lin, “Freeform lens design for LED collimating illumination,” Opt. Express 20, 10984–10995 (2012).
[CrossRef]

2011 (3)

C. Peng, X. Li, P. Zhang, L. Xiong, and X. Liu, “RGB high brightness LED modules for projection display application,” J. Display Technol. 7, 448–453 (2011).
[CrossRef]

W. S. Sun, Y. C. Chiang, and C. H. Tsuei, “Optical design for the DLP pocket projector using LED light source,” Phys. Procedia 19, 301–307 (2011).
[CrossRef]

L. Tan, J. Sun, and H. S. Kwok, “A high efficiency compact size color-sequential LCOS projection engine with 100% NTSC,” SID Symp. Dig. Tech. Papers 42, 1798–1800 (2011).
[CrossRef]

2009 (2)

Z. R. Zheng, X. Hao, and X. Liu, “Freeform surface lens for LED uniform illumination,” Appl. Opt. 48, 6627–6634 (2009).
[CrossRef]

C. L. Bruzzone, R. E. English, and D. J. W. Aastuen, “Compact high-brightness LED illumination for projection systems,” J. Soc. Inf. Disp. 17, 1043–1049 (2009).
[CrossRef]

2008 (2)

2007 (4)

X. Zhao, Z. Fang, J. Cui, X. Zhang, and G. Mu, “Illumination system using LED sources for pocket-size projectors,” Appl. Opt. 46, 522–526 (2007).
[CrossRef]

G. Harbers, S. J. Bierhuizen, and M. R. Krames, “Performance of high power light emitting diodes in display illumination applications,” J. Display Technol. 3, 98–109 (2007).
[CrossRef]

H. Murat, A. Gielen, and H. D. Smet, “Gradually tapered light pipes for illumination of LED projectors,” J. Soc. Inf. Disp. 15, 519–526 (2007).
[CrossRef]

R. Joachim and W. Alexander, “Requirements on LEDs for advanced optical systems,” Proc. SPIE 6486, 64860Z (2007).

2006 (2)

Y. Meuret, B. Vangiel, F. Christiaens, and H. Thienpont, “Efficient illumination in LED-based projection systems using lenslet integrators,” Proc. SPIE 6196, 619605 (2006).
[CrossRef]

H. Murat, H. D. Smet, and D. Uypers, “Compact LED projector with tapered light pipes for moderate light output applications,” Displays 27, 117–123 (2006).
[CrossRef]

2005 (1)

E. F. Schubert and J. K. Kim, “Solid-state light sources getting smart,” Science 308, 1274–1278 (2005).
[CrossRef]

2000 (1)

D. E. Slobodin and C. Biber, “Ultraportable projector progress and prospects,” Proc. SPIE 3954, 19–26 (2000).
[CrossRef]

Aastuen, D. J. W.

C. L. Bruzzone, R. E. English, and D. J. W. Aastuen, “Compact high-brightness LED illumination for projection systems,” J. Soc. Inf. Disp. 17, 1043–1049 (2009).
[CrossRef]

Alexander, W.

R. Joachim and W. Alexander, “Requirements on LEDs for advanced optical systems,” Proc. SPIE 6486, 64860Z (2007).

Biber, C.

D. E. Slobodin and C. Biber, “Ultraportable projector progress and prospects,” Proc. SPIE 3954, 19–26 (2000).
[CrossRef]

Bierhuizen, S. J.

Bruzzone, C. L.

C. L. Bruzzone, R. E. English, and D. J. W. Aastuen, “Compact high-brightness LED illumination for projection systems,” J. Soc. Inf. Disp. 17, 1043–1049 (2009).
[CrossRef]

Buckley, E.

E. Buckley, “On proximity detection systems for pico-projectors,” J. Soc. Inf. Disp. 20, 297–299 (2012).
[CrossRef]

Cassarly, W. J.

W. J. Cassarly, “High-brightness LEDs,” Opt. Photon. News 19(1), 18–23 (2008).
[CrossRef]

Chen, E. G.

E. G. Chen, P. Liu, and F. H. Yu, “Synchronized parameter optimization of the double freeform lenses illumination system used for the CF-LCoS pico-projectors,” Opt. Laser Technol. 44, 2080–2087 (2012).
[CrossRef]

Chen, J.

Chen, S.

S. Chen and K. Chuang, “Illumination system and projection apparatus,” U.S. patent0,291,484 (December20, 2007).

Cheng, C.

Chern, J.

Chiang, Y. C.

W. S. Sun, Y. C. Chiang, and C. H. Tsuei, “Optical design for the DLP pocket projector using LED light source,” Phys. Procedia 19, 301–307 (2011).
[CrossRef]

Christiaens, F.

Y. Meuret, B. Vangiel, F. Christiaens, and H. Thienpont, “Efficient illumination in LED-based projection systems using lenslet integrators,” Proc. SPIE 6196, 619605 (2006).
[CrossRef]

Chuang, K.

S. Chen and K. Chuang, “Illumination system and projection apparatus,” U.S. patent0,291,484 (December20, 2007).

Cui, J.

English, R. E.

C. L. Bruzzone, R. E. English, and D. J. W. Aastuen, “Compact high-brightness LED illumination for projection systems,” J. Soc. Inf. Disp. 17, 1043–1049 (2009).
[CrossRef]

Fang, Z.

Gielen, A.

H. Murat, A. Gielen, and H. D. Smet, “Gradually tapered light pipes for illumination of LED projectors,” J. Soc. Inf. Disp. 15, 519–526 (2007).
[CrossRef]

Grasser, R.

A. G. Huibers and R. Grasser, “Light combiner,” U.S. patent0,251,783 (October8, 2009).

Hao, X.

Harbers, G.

Huang, K.

Huibers, A. G.

A. G. Huibers and R. Grasser, “Light combiner,” U.S. patent0,251,783 (October8, 2009).

Joachim, R.

R. Joachim and W. Alexander, “Requirements on LEDs for advanced optical systems,” Proc. SPIE 6486, 64860Z (2007).

Kim, J. K.

E. F. Schubert and J. K. Kim, “Solid-state light sources getting smart,” Science 308, 1274–1278 (2005).
[CrossRef]

Krames, M. R.

Kwok, H. S.

L. Tan, J. Sun, and H. S. Kwok, “A high efficiency compact size color-sequential LCOS projection engine with 100% NTSC,” SID Symp. Dig. Tech. Papers 42, 1798–1800 (2011).
[CrossRef]

Li, H.

Li, X.

Lin, C.

Liu, P.

R. Wu, L. Xu, P. Liu, Y. Zhang, Z. Zheng, H. Li, and X. Liu, “Freeform illumination design: a nonlinear boundary problem for the elliptic Monge–Ampére equation,” Opt. Lett. 38, 229–231 (2013).
[CrossRef]

E. G. Chen, P. Liu, and F. H. Yu, “Synchronized parameter optimization of the double freeform lenses illumination system used for the CF-LCoS pico-projectors,” Opt. Laser Technol. 44, 2080–2087 (2012).
[CrossRef]

Liu, T.

Liu, X.

Meuret, Y.

Y. Meuret, B. Vangiel, F. Christiaens, and H. Thienpont, “Efficient illumination in LED-based projection systems using lenslet integrators,” Proc. SPIE 6196, 619605 (2006).
[CrossRef]

Mu, G.

Murat, H.

H. Murat, A. Gielen, and H. D. Smet, “Gradually tapered light pipes for illumination of LED projectors,” J. Soc. Inf. Disp. 15, 519–526 (2007).
[CrossRef]

H. Murat, H. D. Smet, and D. Uypers, “Compact LED projector with tapered light pipes for moderate light output applications,” Displays 27, 117–123 (2006).
[CrossRef]

Peng, C.

Schubert, E. F.

E. F. Schubert and J. K. Kim, “Solid-state light sources getting smart,” Science 308, 1274–1278 (2005).
[CrossRef]

Slobodin, D. E.

D. E. Slobodin and C. Biber, “Ultraportable projector progress and prospects,” Proc. SPIE 3954, 19–26 (2000).
[CrossRef]

Smet, H. D.

H. Murat, A. Gielen, and H. D. Smet, “Gradually tapered light pipes for illumination of LED projectors,” J. Soc. Inf. Disp. 15, 519–526 (2007).
[CrossRef]

H. Murat, H. D. Smet, and D. Uypers, “Compact LED projector with tapered light pipes for moderate light output applications,” Displays 27, 117–123 (2006).
[CrossRef]

Sun, J.

L. Tan, J. Sun, and H. S. Kwok, “A high efficiency compact size color-sequential LCOS projection engine with 100% NTSC,” SID Symp. Dig. Tech. Papers 42, 1798–1800 (2011).
[CrossRef]

Sun, W. S.

W. S. Sun, Y. C. Chiang, and C. H. Tsuei, “Optical design for the DLP pocket projector using LED light source,” Phys. Procedia 19, 301–307 (2011).
[CrossRef]

Tan, L.

L. Tan, J. Sun, and H. S. Kwok, “A high efficiency compact size color-sequential LCOS projection engine with 100% NTSC,” SID Symp. Dig. Tech. Papers 42, 1798–1800 (2011).
[CrossRef]

Thienpont, H.

Y. Meuret, B. Vangiel, F. Christiaens, and H. Thienpont, “Efficient illumination in LED-based projection systems using lenslet integrators,” Proc. SPIE 6196, 619605 (2006).
[CrossRef]

Tsai, M.

Tsuei, C. H.

W. S. Sun, Y. C. Chiang, and C. H. Tsuei, “Optical design for the DLP pocket projector using LED light source,” Phys. Procedia 19, 301–307 (2011).
[CrossRef]

Uypers, D.

H. Murat, H. D. Smet, and D. Uypers, “Compact LED projector with tapered light pipes for moderate light output applications,” Displays 27, 117–123 (2006).
[CrossRef]

Vangiel, B.

Y. Meuret, B. Vangiel, F. Christiaens, and H. Thienpont, “Efficient illumination in LED-based projection systems using lenslet integrators,” Proc. SPIE 6196, 619605 (2006).
[CrossRef]

Wang, T.

Wu, R.

Xiong, L.

Xu, L.

Yu, F. H.

E. G. Chen, P. Liu, and F. H. Yu, “Synchronized parameter optimization of the double freeform lenses illumination system used for the CF-LCoS pico-projectors,” Opt. Laser Technol. 44, 2080–2087 (2012).
[CrossRef]

Zhang, P.

Zhang, X.

Zhang, Y.

Zhao, X.

Zheng, Z.

Zheng, Z. R.

Appl. Opt. (3)

Displays (1)

H. Murat, H. D. Smet, and D. Uypers, “Compact LED projector with tapered light pipes for moderate light output applications,” Displays 27, 117–123 (2006).
[CrossRef]

J. Display Technol. (2)

J. Soc. Inf. Disp. (3)

H. Murat, A. Gielen, and H. D. Smet, “Gradually tapered light pipes for illumination of LED projectors,” J. Soc. Inf. Disp. 15, 519–526 (2007).
[CrossRef]

C. L. Bruzzone, R. E. English, and D. J. W. Aastuen, “Compact high-brightness LED illumination for projection systems,” J. Soc. Inf. Disp. 17, 1043–1049 (2009).
[CrossRef]

E. Buckley, “On proximity detection systems for pico-projectors,” J. Soc. Inf. Disp. 20, 297–299 (2012).
[CrossRef]

Opt. Express (1)

Opt. Laser Technol. (1)

E. G. Chen, P. Liu, and F. H. Yu, “Synchronized parameter optimization of the double freeform lenses illumination system used for the CF-LCoS pico-projectors,” Opt. Laser Technol. 44, 2080–2087 (2012).
[CrossRef]

Opt. Lett. (1)

Opt. Photon. News (1)

W. J. Cassarly, “High-brightness LEDs,” Opt. Photon. News 19(1), 18–23 (2008).
[CrossRef]

Phys. Procedia (1)

W. S. Sun, Y. C. Chiang, and C. H. Tsuei, “Optical design for the DLP pocket projector using LED light source,” Phys. Procedia 19, 301–307 (2011).
[CrossRef]

Proc. SPIE (3)

D. E. Slobodin and C. Biber, “Ultraportable projector progress and prospects,” Proc. SPIE 3954, 19–26 (2000).
[CrossRef]

Y. Meuret, B. Vangiel, F. Christiaens, and H. Thienpont, “Efficient illumination in LED-based projection systems using lenslet integrators,” Proc. SPIE 6196, 619605 (2006).
[CrossRef]

R. Joachim and W. Alexander, “Requirements on LEDs for advanced optical systems,” Proc. SPIE 6486, 64860Z (2007).

Science (1)

E. F. Schubert and J. K. Kim, “Solid-state light sources getting smart,” Science 308, 1274–1278 (2005).
[CrossRef]

SID Symp. Dig. Tech. Papers (1)

L. Tan, J. Sun, and H. S. Kwok, “A high efficiency compact size color-sequential LCOS projection engine with 100% NTSC,” SID Symp. Dig. Tech. Papers 42, 1798–1800 (2011).
[CrossRef]

Other (2)

A. G. Huibers and R. Grasser, “Light combiner,” U.S. patent0,251,783 (October8, 2009).

S. Chen and K. Chuang, “Illumination system and projection apparatus,” U.S. patent0,291,484 (December20, 2007).

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Figures (13)

Fig. 1.
Fig. 1.

Schematic prototype of the DDM system.

Fig. 2.
Fig. 2.

Location and rotation angle of the red/blue dichroic mirrors based on off-axis LED sources.

Fig. 3.
Fig. 3.

Schematic diagram of OLD in the DDM system.

Fig. 4.
Fig. 4.

Design flow chart of the DDM system for projection display.

Fig. 5.
Fig. 5.

Optical layout of the designed DDM system for a micro-projection system.

Fig. 6.
Fig. 6.

Ray-tracing simulation of the RGB LED in DDM system.

Fig. 7.
Fig. 7.

(a) Ray-tracing result without considering the OLD compensation. (b) Ray-tracing result considering the OLD compensation.

Fig. 8.
Fig. 8.

Optical engine equipped with the specifically designed DDM system.

Fig. 9.
Fig. 9.

Separate tri-colored uniform illumination on the micro-display panel.

Fig. 10.
Fig. 10.

(a) Actual lighting image and (b) corresponding irradiance distribution curve.

Fig. 11.
Fig. 11.

Optical architecture of (a) PAM, (b) XAM, and (c) DDM system for micro-projection display.

Fig. 12.
Fig. 12.

Colored light concentration of (a) PAM, (b) XAM, and (c) DDM systems within the virtual screen.

Fig. 13.
Fig. 13.

Critical factor comparison of (a) PAM, (b) XAM, and (c) DDM color mixing systems.

Tables (2)

Tables Icon

Table 1. Parameters of the Designed DDM System

Tables Icon

Table 2. Dimension Comparison of the Traditional and Improved Systems

Equations (8)

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

{α1=β2α2=β1sinα1=n·sinβ1=n·sinα2=sinβ2,
l=dcosα2,
t=dcosα2·sin(α1α2).
t=d·sinα1·(1cosα1n2sin2α1).
β2=π2(π4+θb2)=π4θb2.
t=22d(cosθb2sinθb2)d2(cos2θb2sin2θb2)n2+sinθb2cosθb212.
t=22d(cosθr2+sinθr2)d2(cos2θr2sin2θr2)n2sinθr2cosθr212,
T=22d(cosθb2sinθb2+cosθr2+sinθr2)d2(cos2θb2sin2θb2)n2+sinθb2cosθb212d2(cos2θr2sin2θr2)n2sinθr2cosθr212,

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