Abstract

The output colour distributions from red, green and blue (RGB) LEDs mixed with cross linked PMMA micro particle doped PMMA mixing rods is compared to output from a plain PMMA mixing rod. Distinctive patterns with clear colour separation result with the undoped rod. These are homogenised by our mixers, resulting in white light. Light output has been photographed, measured and computer simulated at a distance of 10 cm from the output end of the rods.

© 2004 Optical Society of America

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References

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  1. N. Narendran and L. Deng, "Color Rendering Properties of LED Light Sources," in Solid State Lighting II, Proc. SPIE 4776, 61-67 (2002).
  2. Y. Martynov, H. Konijn, N. Pfeffer et al., "High-efficiency slim LED backlight system with mixing light guide," SID Intl. Symp. Digest Tech., 43.3 (2003).
    [CrossRef]
  3. F. Zhao, N. Narendran, and J. Van Derlofske," Optical elements for mixing colored LEDs to create white light," <a href="http://www.lrc.rpi.edu/programs/solidstate/completedProjects.asp?ID=48">http://www.lrc.rpi.edu/programs/solidstate/completedProjects.asp?ID=48<a/>.
  4. G. B. Smith, J. C. Jonsson and J. Franklin, "Spectral and global diffuse properties of high-performance translucent polymer sheets for energy efficient lighting and skylights," Appl. Opt. 42 (19), 3981-3991 (2003).
    [CrossRef] [PubMed]
  5. C. Deller, G. B. Smith, J Franklin et al., "The integration of forward light transport and lateral illumination of polymer optical fibre," in Proceedings of the Australian Institute of Physics 15th Biennial Congress (2002), Vol. 5192-11, pp. 307-309.
  6. W. J. Cassarly, "LED Modeling: Pros and cons of Common Methods," Phot.Tech Briefs, (April 2002).
  7. J. D. Foley, A. van Dam, S. K. Feiner et al., Computer Graphics Principles and Practice, 2nd ed. (Addison- Wesley, 1995).

Appl. Opt. (1)

Australian Inst. of Phys. 15th Biennial (1)

C. Deller, G. B. Smith, J Franklin et al., "The integration of forward light transport and lateral illumination of polymer optical fibre," in Proceedings of the Australian Institute of Physics 15th Biennial Congress (2002), Vol. 5192-11, pp. 307-309.

Phot.Tech Briefs (1)

W. J. Cassarly, "LED Modeling: Pros and cons of Common Methods," Phot.Tech Briefs, (April 2002).

SID Intl. Symp. Digest Tech. (1)

Y. Martynov, H. Konijn, N. Pfeffer et al., "High-efficiency slim LED backlight system with mixing light guide," SID Intl. Symp. Digest Tech., 43.3 (2003).
[CrossRef]

Solid State Lighting II, Proc. SPIE (1)

N. Narendran and L. Deng, "Color Rendering Properties of LED Light Sources," in Solid State Lighting II, Proc. SPIE 4776, 61-67 (2002).

Other (2)

F. Zhao, N. Narendran, and J. Van Derlofske," Optical elements for mixing colored LEDs to create white light," <a href="http://www.lrc.rpi.edu/programs/solidstate/completedProjects.asp?ID=48">http://www.lrc.rpi.edu/programs/solidstate/completedProjects.asp?ID=48<a/>.

J. D. Foley, A. van Dam, S. K. Feiner et al., Computer Graphics Principles and Practice, 2nd ed. (Addison- Wesley, 1995).

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Figures (7)

Fig. 1.
Fig. 1.

(a) Experimental setup, showing (from left): alignment laser, LED array, acrylic mixing rod, frosted glass screen and the translational stage with photometric detector. (b) 1931 CIE diagram showing LED source chromaticity coordinates, and the coordinates of the computer monitor’s phosphors. Inset: 3 mm LED array.

Fig. 2.
Fig. 2.

(a) Modeled illuminance falling on detector 10 cm from end of the undoped 10 cm acrylic mixing rod. Source diameter is 2 mm. (b) Measured angular distribution of the source R, G and B LEDs. The black line, closely following the red profile, shows the functions used in the computer source modeling. (c) Cross-section through the centre of a), showing computed R, G and B components, and the total in black. (d) Corresponding measured illuminance.

Fig. 3.
Fig. 3.

(a) Modeled output colour mix falling on detector 10 cm from end of 10 cm acrylic rod. Pixel size is 1 mm. Source diameter is 2 mm. (b-e) Photographs of experimental results modeled in (a), taken at varying viewing angles. (f) Measured colours in a horizontal strip through the centre, which has been converted to RGB via calculations. (g-i) modeled strip, using source diameters of 1, 2 and 3 mm, respectively.

Fig. 4.
Fig. 4.

Output colour falling on detector 10 cm from end of 10 cm long 15K rod. Pixel size is 1 mm. (a) Measured horizontal strip through the centre, converted to RGB. (b-c) modeled strip, using source diameters of 1 and 2 mm respectively.

Fig. 5.
Fig. 5.

Projected light 10 cm from the end of 100K rods. (a-c) 10 cm rod length. (a, b) photographed results, (c) computer simulation. (d-h) 8.84 cm rod length. (d) photographed results. (f) computer simulation. (g, h). measured and modeled strips through center crosssection. (e) CIE coordinates corresponding to (g) and (h).

Fig. 6.
Fig. 6.

Modeled colour distribution for 10 cm mixing rods. (a-c) 1 cm from the rod’s end. (a) PMMA, (b) low concentration, (c) high concentration TRIMM. (d-f) 100 cm from the rod’s end. (d) PMMA, (e) low concentration (15K) TRIMM, (f) high concentration (100K) TRIMM.

Fig. 7.
Fig. 7.

Chromaticity coordinates; (a) CIEx, (b) CIEy for simulations 1 cm from the end of the three 10 cm mixing rods shown in Fig. 5. (a-c)

Equations (2)

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x i = ( I Ri x R + I Gi x G + I Bi x B ) ( I Ri + I Gi + I Bi )
X i = ( x i y i ) Y i Z i = ( z i y i ) Y i

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