Abstract

Efficiency of liquid crystal displays highly depends on the amount of polarized light emerging from the backlight module. In this paper, a backlight architecture using a nanoimprint wire grid polarizer for polarization recycling is proposed and studied, in which the extraction efficiency of polarized light is the major concern. The backlight module is composed of the stack of a wire grid polarizer, a lenticular array and a light guide plate. The light guide plate features interleaving v-groove and trapezoidal ridge coated with aluminum on the top surface, and scattering dot array on the bottom. The angular divergence of emerging light from the light guide plate can be well constrained so as to exploit the angular range with the best transmission of polarized light for the wire grid polarizer. The prototype of a 2.5-inch module has demonstrated an angular divergence of 48°. The overall extraction efficiency of polarized light enhanced by 21% and uniformity of 76% have been achieved.

© 2012 OSA

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2011

C. F. Lin, Y. B. Fang, and P. H. Yang, “Optimized micro-prism diffusion film for slim-type bottom-lit backlight units,” J. Disp. Technol. 7(1), 3–9 (2011).
[CrossRef]

K. Käläntär, “A directional backlight with narrow angular luminance distribution for widening viewing angle of a LCD with a front-surface-light-scattering film,” SID 11 Digest. 42(1), 890–893 (2011).

K. Takano, H. Yokoyama, A. Ichii, I. Morimoto, and M. Hangyo, “Wire-grid polarizer sheet in the terahertz region fabricated by nanoimprint technology,” Opt. Lett. 36(14), 2665–2667 (2011).
[CrossRef] [PubMed]

2009

2008

Z. B. Ge and S. T. Wu, “Nanowire grid polarizer for energy efficient and wide-view liquid crystal displays,” Appl. Phys. Lett. 93(12), 121104 (2008).
[CrossRef]

P. C. Chen and H. L. Kuo, “Color shift improvement in a broadband cholesteric liquid crystal polarizer through computational simulations,” Proc. SPIE 7050, 705015, 705015-8 (2008).
[CrossRef]

2007

2006

S. Aoyama, A. Funamoto, and K. Imanaka, “Hybrid normal-reverse prism coupler for light-emitting diode backlight systems,” Appl. Opt. 45(28), 7273–7278 (2006).
[CrossRef] [PubMed]

J. J. Wang, L. Chen, X. M. Liu, P. Sciortino, F. Liu, F. Walters, and X. G. Deng, “30-nm-wide aluminum nanowire grid for ultrahigh contrast and transmittance polarizers made by UV-nanoimprint lithography,” Appl. Phys. Lett. 89(14), 141105 (2006).
[CrossRef]

2005

2003

Y. Iwamoto and Y. Iimura, “Transmitted light enhancement of electric-field-controlled multidomain vertically aligned liquid crystal displays using circular polarizers and a cholesteric liquid crystal film,” Jpn. J. Appl. Phys. 42, L51–L53 (2003).
[CrossRef]

X. J. Yu and H. S. Kwok, “Optical wire-grid polarizers at oblique angles of incidence,” J. Appl. Phys. 93(8), 4407–4412 (2003).
[CrossRef]

2002

1999

V. C. Ballenegger and T. A. Weber, “The Ewald–Oseen extinction theorem and extinction lengths,” Am. J. Phys. 67(7), 599–605 (1999).
[CrossRef]

1998

L. Li, J. F. Li, B. S. Fan, Y. Q. Jiang, and S. M. Faris, “Reflective cholesteric liquid crystal polarizers and their applications,” Proc. SPIE 3560, 33–40 (1998).
[CrossRef]

Aoyama, S.

Baik, S. H.

Ballenegger, V. C.

V. C. Ballenegger and T. A. Weber, “The Ewald–Oseen extinction theorem and extinction lengths,” Am. J. Phys. 67(7), 599–605 (1999).
[CrossRef]

Chen, L.

J. J. Wang, L. Chen, X. M. Liu, P. Sciortino, F. Liu, F. Walters, and X. G. Deng, “30-nm-wide aluminum nanowire grid for ultrahigh contrast and transmittance polarizers made by UV-nanoimprint lithography,” Appl. Phys. Lett. 89(14), 141105 (2006).
[CrossRef]

Chen, P. C.

P. C. Chen and H. L. Kuo, “Color shift improvement in a broadband cholesteric liquid crystal polarizer through computational simulations,” Proc. SPIE 7050, 705015, 705015-8 (2008).
[CrossRef]

Choi, H. Y.

Choi, W. S.

Cornelissen, H.

de Boer, D.

Deng, X. G.

J. J. Wang, L. Chen, X. M. Liu, P. Sciortino, F. Liu, F. Walters, and X. G. Deng, “30-nm-wide aluminum nanowire grid for ultrahigh contrast and transmittance polarizers made by UV-nanoimprint lithography,” Appl. Phys. Lett. 89(14), 141105 (2006).
[CrossRef]

Fan, B. S.

L. Li, J. F. Li, B. S. Fan, Y. Q. Jiang, and S. M. Faris, “Reflective cholesteric liquid crystal polarizers and their applications,” Proc. SPIE 3560, 33–40 (1998).
[CrossRef]

Fang, Y. B.

C. F. Lin, Y. B. Fang, and P. H. Yang, “Optimized micro-prism diffusion film for slim-type bottom-lit backlight units,” J. Disp. Technol. 7(1), 3–9 (2011).
[CrossRef]

Faris, S. M.

L. Li, J. F. Li, B. S. Fan, Y. Q. Jiang, and S. M. Faris, “Reflective cholesteric liquid crystal polarizers and their applications,” Proc. SPIE 3560, 33–40 (1998).
[CrossRef]

Funamoto, A.

Gardner, E.

Ge, Z. B.

Z. B. Ge and S. T. Wu, “Nanowire grid polarizer for energy efficient and wide-view liquid crystal displays,” Appl. Phys. Lett. 93(12), 121104 (2008).
[CrossRef]

Hangyo, M.

Hansen, D.

Hwang, S. K.

Ichii, A.

Iimura, Y.

Y. Iwamoto and Y. Iimura, “Transmitted light enhancement of electric-field-controlled multidomain vertically aligned liquid crystal displays using circular polarizers and a cholesteric liquid crystal film,” Jpn. J. Appl. Phys. 42, L51–L53 (2003).
[CrossRef]

Imanaka, K.

Iwamoto, Y.

Y. Iwamoto and Y. Iimura, “Transmitted light enhancement of electric-field-controlled multidomain vertically aligned liquid crystal displays using circular polarizers and a cholesteric liquid crystal film,” Jpn. J. Appl. Phys. 42, L51–L53 (2003).
[CrossRef]

Jiang, Y. Q.

L. Li, J. F. Li, B. S. Fan, Y. Q. Jiang, and S. M. Faris, “Reflective cholesteric liquid crystal polarizers and their applications,” Proc. SPIE 3560, 33–40 (1998).
[CrossRef]

Käläntär, K.

K. Käläntär, “A directional backlight with narrow angular luminance distribution for widening viewing angle of a LCD with a front-surface-light-scattering film,” SID 11 Digest. 42(1), 890–893 (2011).

Kang, S.-H.

Kelly, J.

Kim, B.-K.

Kim, S.-H.

Kim, Y. G.

Kim, Y.-G.

Kuo, H. L.

P. C. Chen and H. L. Kuo, “Color shift improvement in a broadband cholesteric liquid crystal polarizer through computational simulations,” Proc. SPIE 7050, 705015, 705015-8 (2008).
[CrossRef]

Kwok, H. S.

X. J. Yu and H. S. Kwok, “Optical wire-grid polarizers at oblique angles of incidence,” J. Appl. Phys. 93(8), 4407–4412 (2003).
[CrossRef]

Kwon, J. H.

Kwon, J.-H.

Lavrentovich, M.

Lee, B. K.

Lee, H. S.

Lee, J. H.

Lee, J. W.

Li, J. F.

L. Li, J. F. Li, B. S. Fan, Y. Q. Jiang, and S. M. Faris, “Reflective cholesteric liquid crystal polarizers and their applications,” Proc. SPIE 3560, 33–40 (1998).
[CrossRef]

Li, L.

L. Li, J. F. Li, B. S. Fan, Y. Q. Jiang, and S. M. Faris, “Reflective cholesteric liquid crystal polarizers and their applications,” Proc. SPIE 3560, 33–40 (1998).
[CrossRef]

Lin, C. F.

C. F. Lin, Y. B. Fang, and P. H. Yang, “Optimized micro-prism diffusion film for slim-type bottom-lit backlight units,” J. Disp. Technol. 7(1), 3–9 (2011).
[CrossRef]

Liu, F.

J. J. Wang, L. Chen, X. M. Liu, P. Sciortino, F. Liu, F. Walters, and X. G. Deng, “30-nm-wide aluminum nanowire grid for ultrahigh contrast and transmittance polarizers made by UV-nanoimprint lithography,” Appl. Phys. Lett. 89(14), 141105 (2006).
[CrossRef]

Liu, X. M.

J. J. Wang, L. Chen, X. M. Liu, P. Sciortino, F. Liu, F. Walters, and X. G. Deng, “30-nm-wide aluminum nanowire grid for ultrahigh contrast and transmittance polarizers made by UV-nanoimprint lithography,” Appl. Phys. Lett. 89(14), 141105 (2006).
[CrossRef]

Meissner, S. C.

Moon, W.-T.

Morimoto, I.

Park, G.

Park, G.-J.

Park, J.-H.

Sciortino, P.

J. J. Wang, L. Chen, X. M. Liu, P. Sciortino, F. Liu, F. Walters, and X. G. Deng, “30-nm-wide aluminum nanowire grid for ultrahigh contrast and transmittance polarizers made by UV-nanoimprint lithography,” Appl. Phys. Lett. 89(14), 141105 (2006).
[CrossRef]

Sergan, T.

Shin, J.-K.

Soh, H.-S.

Sudol, R. J.

Takano, K.

Urbach, H. P.

Walters, F.

J. J. Wang, L. Chen, X. M. Liu, P. Sciortino, F. Liu, F. Walters, and X. G. Deng, “30-nm-wide aluminum nanowire grid for ultrahigh contrast and transmittance polarizers made by UV-nanoimprint lithography,” Appl. Phys. Lett. 89(14), 141105 (2006).
[CrossRef]

Wang, J. J.

J. J. Wang, L. Chen, X. M. Liu, P. Sciortino, F. Liu, F. Walters, and X. G. Deng, “30-nm-wide aluminum nanowire grid for ultrahigh contrast and transmittance polarizers made by UV-nanoimprint lithography,” Appl. Phys. Lett. 89(14), 141105 (2006).
[CrossRef]

Weber, T. A.

V. C. Ballenegger and T. A. Weber, “The Ewald–Oseen extinction theorem and extinction lengths,” Am. J. Phys. 67(7), 599–605 (1999).
[CrossRef]

Wu, S. T.

Z. B. Ge and S. T. Wu, “Nanowire grid polarizer for energy efficient and wide-view liquid crystal displays,” Appl. Phys. Lett. 93(12), 121104 (2008).
[CrossRef]

Xu, M.

Yang, P. H.

C. F. Lin, Y. B. Fang, and P. H. Yang, “Optimized micro-prism diffusion film for slim-type bottom-lit backlight units,” J. Disp. Technol. 7(1), 3–9 (2011).
[CrossRef]

Yi, J.-H.

Yokoyama, H.

Yoon, J. B.

Yu, X. J.

X. J. Yu and H. S. Kwok, “Optical wire-grid polarizers at oblique angles of incidence,” J. Appl. Phys. 93(8), 4407–4412 (2003).
[CrossRef]

Am. J. Phys.

V. C. Ballenegger and T. A. Weber, “The Ewald–Oseen extinction theorem and extinction lengths,” Am. J. Phys. 67(7), 599–605 (1999).
[CrossRef]

Appl. Opt.

Appl. Phys. Lett.

Z. B. Ge and S. T. Wu, “Nanowire grid polarizer for energy efficient and wide-view liquid crystal displays,” Appl. Phys. Lett. 93(12), 121104 (2008).
[CrossRef]

J. J. Wang, L. Chen, X. M. Liu, P. Sciortino, F. Liu, F. Walters, and X. G. Deng, “30-nm-wide aluminum nanowire grid for ultrahigh contrast and transmittance polarizers made by UV-nanoimprint lithography,” Appl. Phys. Lett. 89(14), 141105 (2006).
[CrossRef]

J. Appl. Phys.

X. J. Yu and H. S. Kwok, “Optical wire-grid polarizers at oblique angles of incidence,” J. Appl. Phys. 93(8), 4407–4412 (2003).
[CrossRef]

J. Disp. Technol.

C. F. Lin, Y. B. Fang, and P. H. Yang, “Optimized micro-prism diffusion film for slim-type bottom-lit backlight units,” J. Disp. Technol. 7(1), 3–9 (2011).
[CrossRef]

J. Opt. Soc. Am. A

J. Opt. Soc. Korea

Jpn. J. Appl. Phys.

Y. Iwamoto and Y. Iimura, “Transmitted light enhancement of electric-field-controlled multidomain vertically aligned liquid crystal displays using circular polarizers and a cholesteric liquid crystal film,” Jpn. J. Appl. Phys. 42, L51–L53 (2003).
[CrossRef]

Opt. Express

Opt. Lett.

Proc. SPIE

P. C. Chen and H. L. Kuo, “Color shift improvement in a broadband cholesteric liquid crystal polarizer through computational simulations,” Proc. SPIE 7050, 705015, 705015-8 (2008).
[CrossRef]

L. Li, J. F. Li, B. S. Fan, Y. Q. Jiang, and S. M. Faris, “Reflective cholesteric liquid crystal polarizers and their applications,” Proc. SPIE 3560, 33–40 (1998).
[CrossRef]

SID 11 Digest.

K. Käläntär, “A directional backlight with narrow angular luminance distribution for widening viewing angle of a LCD with a front-surface-light-scattering film,” SID 11 Digest. 42(1), 890–893 (2011).

Other

M. Born and E. Wolf, Principles of Optics, 4th ed. (Pergamon, 1970).

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Figures (12)

Fig. 1
Fig. 1

(a) Wire grid polarizer and its birefringence property. (b) Schematic diagram of the polarized backlight module with WGP polarizer.

Fig. 2
Fig. 2

(a) Cross-section profile of the nanoimprinted WGP from SEM. (b) Transmission property of the 5cmx5cm WGP on 4-inch glass substrate in two orthogonal directions examined in front of a LCD monitor. Double arrow denotes transmission axis for both LCD and WGP.

Fig. 3
Fig. 3

Spectral transmittance of WGP at some specific incident angles (solid line: measured data; dash line: simulation data).

Fig. 4
Fig. 4

(a) Schematic diagram of AL-LGP. (b) Illustration of possible ray path in AL-LGP.

Fig. 5
Fig. 5

Angular profile of emerging light from AL-LGP compared with Lambertian profile.

Fig. 6
Fig. 6

(a) Lenticular array with feature parameters. (b) Configuration of AL-LGP covered with lenticular array.

Fig. 7
Fig. 7

Geometry of optical ray tracing for the lenticular lenslet and the optical parameters for determining the optical matrices.

Fig. 8
Fig. 8

Comparison of normalized intensity distribution of different backlight structures from simulation.

Fig. 9
Fig. 9

Illuminance distribution of DC-BLM with stack of AL-LGP and the lenticular array by simulation.

Fig. 10
Fig. 10

(a) Diamond tooling process for AL-LGP. (b) Fabrication process for the lenticular sheet.

Fig. 11
Fig. 11

(a) 2.5-inch PMMA AL-LGP. (b) 2.5-inch PET lenticular array film replicated by UV imprint process with a grooved master mold.

Fig. 12
Fig. 12

(a) 5 points on-axis luminance of the 2.5-inch DC-BLM. (b) Measured angular intensity of the proposed DC-BLM and a diffuser-stacked module.

Tables (3)

Tables Icon

Table 1 Parameters of Lenticular Lenslet

Tables Icon

Table 2 Comparison of Different Backlight Architectures Basing on the Same LED Input; Df: Diffuser Sheet, Pr: Prism Sheet.

Tables Icon

Table 3 Optical Performance of the DC-BLM and Cross-Prism-Stacked BLM (CPS-BLM)

Equations (2)

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

Φ o p = Φ 0 × E o c × E p r × T p o l
r = ( ƒ + Γ ) ( n 1 )

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