Abstract

Most plastic diffusers are either of surface-relief or particle-diffusing types, based on different principles and fabrication methods. This paper reports an innovative extrusion roller embossing process, which enables the fabrication of diffusers with both surface-relief and particle-diffusing functions. An extruder with die is employed to fabricate the thin film of PC/bead composite; the roller micro-embossing process is used to replicate the microstructure onto the surface of PC composite film. A metallic roller mold with microstructures is fabricated using turning process. During the extrusion rolling embossing process, the extruded film of PC with diffusion beads is immediately pressed against the surface of the roller mold. Under the proper processing parameters, the plastic diffusers integrating surface-relief and particle-diffusing functions have been successfully fabricated. The shape, uniformity, and optical properties of fabricated diffuser have been verified. This method shows the great potential for continuous fabrication of high-performance plastic diffusers integrating surface-relief and particle-diffusing functions with high throughput.

© 2008 Optical Society of America

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References

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  1. G. H. Kim, "A PMMA composite as an optical diffuser in a liquid crystal display backlight unit (BLU)," Eur. Polym. J. 41, 1729-1737 (2005).
    [CrossRef]
  2. G. H. Kim, W. J. Kim, S. M. Kim, and J. G. Son, "Analysis of thermo-physical and optical properties of a diffuser using PET/PC/PBT copolymer in LCD backlight units," Displays 26, 37-43 (2005).
    [CrossRef]
  3. Q1. G. H. Kim and J. H. Park, "A PMMA optical diffuser fabricated using an electrospray method," Appl. Phys. A 86, 347-351 (2007).
    [CrossRef]
  4. KEIWA Incorporated, http://www.keiwa.co.jp/e/index.html.
  5. Q2. T. K. Shih, C. F. Chen, J. R. Ho, and F. T. Chuang, "Fabrication of PDMS (polydimethylsiloxane) microlens and diffuser using replica molding," Microelectron. Eng. 83, 2499-2503 (2006).
    [CrossRef]
  6. S. I. Kim, Y. S. Choi, Y. N. Ham, C. Y. Park, and J. M. Kim, "Holographic diffuser by use of a silver halide sensitized gelatin process," Appl. Opt. 42, 2482-2491 (2003).
    [CrossRef] [PubMed]
  7. D. Sakai, K. Harada, S. I. Kamemaru, M. A. El-Morsy, M. Itoh, and T. Yatagai, "Direct fabrication of surface relief holographic diffusers in azobenzene polymer films," Opt. Rev. 12, 383-386 (2005)
    [CrossRef]
  8. S. I. Chang, J. B. Yoon, H. K. Kim, J. J. Kim, B. K. Lee, and D. H. Shin, "Microlens array diffuser for a light -emitting diode backlight system," Opt. Lett. 31, 3016-3018 (2006).
    [CrossRef] [PubMed]
  9. E. R. Méndez, E. E. García-Guerrero, H. M. Escamilla, A. A. Maradudin, T. A. Leskova, and A. V. Shchegrov, "Photofabrication of random achromatic optical diffusers for uniform illumination," Appl. Opt. 40, 1098-1108 (2001).
    [CrossRef]
  10. E. E. García-Guerrero, E. R. Méndez, H. M. Escamilla, T. A. Leskova, and A. A. Maradudin, "Design and fabrication of random phase diffusers for extending the depth of focus," Opt. Express 15, 910-923 (2007).
    [CrossRef] [PubMed]
  11. M. Parikka, T. Kaikuranta, P. Laakkonen, J. Lautanen, J. Tervo, M. Honkanen, M. Kuittinen, and J. Turunen, "Deterministic diffractive diffusers for displays," Appl. Opt. 40, 2239-2246 (2001).
    [CrossRef]
  12. T. A. Osswald, Polymer Processing Fundamentals (Hanser, Munich, 1998).
  13. L. T. Jiang, T. C. Huang, J. R. Ciou, C. Y. Chang, and S. Y. Yang, "Fabrication of plastic microlens arrays using hybrid extrusion rolling embossing with a metallic cylinder mold fabricated using dry film resist," Opt. Express 15, 12088-12094 (2007).
    [CrossRef] [PubMed]

2007 (3)

2006 (2)

Q2. T. K. Shih, C. F. Chen, J. R. Ho, and F. T. Chuang, "Fabrication of PDMS (polydimethylsiloxane) microlens and diffuser using replica molding," Microelectron. Eng. 83, 2499-2503 (2006).
[CrossRef]

S. I. Chang, J. B. Yoon, H. K. Kim, J. J. Kim, B. K. Lee, and D. H. Shin, "Microlens array diffuser for a light -emitting diode backlight system," Opt. Lett. 31, 3016-3018 (2006).
[CrossRef] [PubMed]

2005 (3)

G. H. Kim, "A PMMA composite as an optical diffuser in a liquid crystal display backlight unit (BLU)," Eur. Polym. J. 41, 1729-1737 (2005).
[CrossRef]

G. H. Kim, W. J. Kim, S. M. Kim, and J. G. Son, "Analysis of thermo-physical and optical properties of a diffuser using PET/PC/PBT copolymer in LCD backlight units," Displays 26, 37-43 (2005).
[CrossRef]

D. Sakai, K. Harada, S. I. Kamemaru, M. A. El-Morsy, M. Itoh, and T. Yatagai, "Direct fabrication of surface relief holographic diffusers in azobenzene polymer films," Opt. Rev. 12, 383-386 (2005)
[CrossRef]

2003 (1)

2001 (2)

Appl. Opt. (3)

Appl. Phys. A (1)

Q1. G. H. Kim and J. H. Park, "A PMMA optical diffuser fabricated using an electrospray method," Appl. Phys. A 86, 347-351 (2007).
[CrossRef]

Displays (1)

G. H. Kim, W. J. Kim, S. M. Kim, and J. G. Son, "Analysis of thermo-physical and optical properties of a diffuser using PET/PC/PBT copolymer in LCD backlight units," Displays 26, 37-43 (2005).
[CrossRef]

Eur. Polym. J. (1)

G. H. Kim, "A PMMA composite as an optical diffuser in a liquid crystal display backlight unit (BLU)," Eur. Polym. J. 41, 1729-1737 (2005).
[CrossRef]

Microelectron. Eng. (1)

Q2. T. K. Shih, C. F. Chen, J. R. Ho, and F. T. Chuang, "Fabrication of PDMS (polydimethylsiloxane) microlens and diffuser using replica molding," Microelectron. Eng. 83, 2499-2503 (2006).
[CrossRef]

Opt. Express (2)

Opt. Lett. (1)

Opt. Rev. (1)

D. Sakai, K. Harada, S. I. Kamemaru, M. A. El-Morsy, M. Itoh, and T. Yatagai, "Direct fabrication of surface relief holographic diffusers in azobenzene polymer films," Opt. Rev. 12, 383-386 (2005)
[CrossRef]

Other (2)

T. A. Osswald, Polymer Processing Fundamentals (Hanser, Munich, 1998).

KEIWA Incorporated, http://www.keiwa.co.jp/e/index.html.

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Figures (4)

Fig. 1.
Fig. 1.

Schematic diagram and photograph showing the hybrid extrusion rolling embossing facility

Fig. 2.
Fig. 2.

(a). Profile projector, (b). optical microscopy, (c). SEM, and (d). surface profiler images of the microstructures on the machined aluminum alloy micro-embossing roller mold.

Fig. 3.
Fig. 3.

(a). SEM and (b). surface profiler images of the microstructures on the fabricated PC composite diffusers. The magnified SEM image (c). of the fabricated diffuser shows the diffusing beads inside the film.

Fig. 4.
Fig. 4.

The images of a laser light source observed behind through (a) a flat pure PC film, (b) a pure PC film with surface microstructures, (c) a flat PC/bead composite film, and (d) a PC/bead composite film with surface microstructures. The PC/bead film with microstructures displays the best diffusing efficiency.

Tables (2)

Tables Icon

Table1. Effects of processing conditions on the quality of replicated microstructures

Tables Icon

Table 2. Measured optical properties of various films as diffusers.

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