Abstract

We have developed a general approach to perform direct measurements of the pretilt angles from 0° to 75° in hybrid-aligned nematic (HAN) liquid-crystal cells whose cell gaps can also be accurately determined with the help of known pretilt angles. In this paper, we have used a Zeeman laser system to measure the angular-dependence phase retardation of the HAN cells and MATLAB mathematical software to carry out theoretical calculations and fit the measured data to derive the pretilt angles. In general, pretilt angles adjacent to opposite substrates of a HAN cell are different. Our measured pretilt angles of the HAN cell were in good agreement with the measured pretilt angles of two accompanying homogenous cells whose alignment methods were the same as applied to opposite substrates of the HAN cell, respectively. The advantage of direct measurement is easily applicable to measure the pretilt angles of aged HAN cells.

© 2013 Optical Society of America

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References

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  1. S. Matsumoto, M. Kawamoto, and K. Mizunoya, “Field‐induced deformation of hybrid‐aligned nematic liquid crystals: New multicolor liquid crystal display,” J. Appl. Phys. 47, 3842–3845 (1976).
    [CrossRef]
  2. T. J. Scheffer and J. Nehring, “Accurate determination of liquid crystal tilt bias angles,” J. Appl. Phys. 48, 1783–1792 (1977).
    [CrossRef]
  3. L. T. Hung, S. Oka, M. Kimura, and T. Akahane, “Determination of polar anchoring strength at vertical alignment nematic liquid crystal-wall interface using thin hybrid alignment nematic cell,” Jpn. J. Appl. Phys. 43, L649–L651 (2004).
    [CrossRef]
  4. T. Ishinabe, Y. Ohno, T. Miyashita, and T. Uchida, “High-precision measurement of polar anchoring strength and elastic constant ratio using hybrid alignment nematic cell,” Jpn. J. Appl. Phys. 47, 8892–8897 (2008).
    [CrossRef]
  5. A. Y. G. Fuh, C. K. Liu, K. T. Cheng, C. L. Ting, and C. C. Chen, “Variable liquid crystal pretilt angles generated by photoalignment in homeotropically aligned azo dye-doped liquid crystals,” Appl. Phys. Lett. 95, 161104 (2009).
    [CrossRef]
  6. S. J. Hwang, “Precise optical retardation measurement of nematic liquid crystal display using the phase-sensitive technique,” J. Display Technol. 1, 77–81 (2005).
    [CrossRef]
  7. S. J. Hwang, S. C. Jeng, and I. M. Hsieh, “Nanoparticle-doped polyimide for controlling the pretilt angle of liquid crystals devices,” Opt. Express 18, 16507–16512 (2010).
    [CrossRef]

2010

2009

A. Y. G. Fuh, C. K. Liu, K. T. Cheng, C. L. Ting, and C. C. Chen, “Variable liquid crystal pretilt angles generated by photoalignment in homeotropically aligned azo dye-doped liquid crystals,” Appl. Phys. Lett. 95, 161104 (2009).
[CrossRef]

2008

T. Ishinabe, Y. Ohno, T. Miyashita, and T. Uchida, “High-precision measurement of polar anchoring strength and elastic constant ratio using hybrid alignment nematic cell,” Jpn. J. Appl. Phys. 47, 8892–8897 (2008).
[CrossRef]

2005

2004

L. T. Hung, S. Oka, M. Kimura, and T. Akahane, “Determination of polar anchoring strength at vertical alignment nematic liquid crystal-wall interface using thin hybrid alignment nematic cell,” Jpn. J. Appl. Phys. 43, L649–L651 (2004).
[CrossRef]

1977

T. J. Scheffer and J. Nehring, “Accurate determination of liquid crystal tilt bias angles,” J. Appl. Phys. 48, 1783–1792 (1977).
[CrossRef]

1976

S. Matsumoto, M. Kawamoto, and K. Mizunoya, “Field‐induced deformation of hybrid‐aligned nematic liquid crystals: New multicolor liquid crystal display,” J. Appl. Phys. 47, 3842–3845 (1976).
[CrossRef]

Akahane, T.

L. T. Hung, S. Oka, M. Kimura, and T. Akahane, “Determination of polar anchoring strength at vertical alignment nematic liquid crystal-wall interface using thin hybrid alignment nematic cell,” Jpn. J. Appl. Phys. 43, L649–L651 (2004).
[CrossRef]

Chen, C. C.

A. Y. G. Fuh, C. K. Liu, K. T. Cheng, C. L. Ting, and C. C. Chen, “Variable liquid crystal pretilt angles generated by photoalignment in homeotropically aligned azo dye-doped liquid crystals,” Appl. Phys. Lett. 95, 161104 (2009).
[CrossRef]

Cheng, K. T.

A. Y. G. Fuh, C. K. Liu, K. T. Cheng, C. L. Ting, and C. C. Chen, “Variable liquid crystal pretilt angles generated by photoalignment in homeotropically aligned azo dye-doped liquid crystals,” Appl. Phys. Lett. 95, 161104 (2009).
[CrossRef]

Fuh, A. Y. G.

A. Y. G. Fuh, C. K. Liu, K. T. Cheng, C. L. Ting, and C. C. Chen, “Variable liquid crystal pretilt angles generated by photoalignment in homeotropically aligned azo dye-doped liquid crystals,” Appl. Phys. Lett. 95, 161104 (2009).
[CrossRef]

Hsieh, I. M.

Hung, L. T.

L. T. Hung, S. Oka, M. Kimura, and T. Akahane, “Determination of polar anchoring strength at vertical alignment nematic liquid crystal-wall interface using thin hybrid alignment nematic cell,” Jpn. J. Appl. Phys. 43, L649–L651 (2004).
[CrossRef]

Hwang, S. J.

Ishinabe, T.

T. Ishinabe, Y. Ohno, T. Miyashita, and T. Uchida, “High-precision measurement of polar anchoring strength and elastic constant ratio using hybrid alignment nematic cell,” Jpn. J. Appl. Phys. 47, 8892–8897 (2008).
[CrossRef]

Jeng, S. C.

Kawamoto, M.

S. Matsumoto, M. Kawamoto, and K. Mizunoya, “Field‐induced deformation of hybrid‐aligned nematic liquid crystals: New multicolor liquid crystal display,” J. Appl. Phys. 47, 3842–3845 (1976).
[CrossRef]

Kimura, M.

L. T. Hung, S. Oka, M. Kimura, and T. Akahane, “Determination of polar anchoring strength at vertical alignment nematic liquid crystal-wall interface using thin hybrid alignment nematic cell,” Jpn. J. Appl. Phys. 43, L649–L651 (2004).
[CrossRef]

Liu, C. K.

A. Y. G. Fuh, C. K. Liu, K. T. Cheng, C. L. Ting, and C. C. Chen, “Variable liquid crystal pretilt angles generated by photoalignment in homeotropically aligned azo dye-doped liquid crystals,” Appl. Phys. Lett. 95, 161104 (2009).
[CrossRef]

Matsumoto, S.

S. Matsumoto, M. Kawamoto, and K. Mizunoya, “Field‐induced deformation of hybrid‐aligned nematic liquid crystals: New multicolor liquid crystal display,” J. Appl. Phys. 47, 3842–3845 (1976).
[CrossRef]

Miyashita, T.

T. Ishinabe, Y. Ohno, T. Miyashita, and T. Uchida, “High-precision measurement of polar anchoring strength and elastic constant ratio using hybrid alignment nematic cell,” Jpn. J. Appl. Phys. 47, 8892–8897 (2008).
[CrossRef]

Mizunoya, K.

S. Matsumoto, M. Kawamoto, and K. Mizunoya, “Field‐induced deformation of hybrid‐aligned nematic liquid crystals: New multicolor liquid crystal display,” J. Appl. Phys. 47, 3842–3845 (1976).
[CrossRef]

Nehring, J.

T. J. Scheffer and J. Nehring, “Accurate determination of liquid crystal tilt bias angles,” J. Appl. Phys. 48, 1783–1792 (1977).
[CrossRef]

Ohno, Y.

T. Ishinabe, Y. Ohno, T. Miyashita, and T. Uchida, “High-precision measurement of polar anchoring strength and elastic constant ratio using hybrid alignment nematic cell,” Jpn. J. Appl. Phys. 47, 8892–8897 (2008).
[CrossRef]

Oka, S.

L. T. Hung, S. Oka, M. Kimura, and T. Akahane, “Determination of polar anchoring strength at vertical alignment nematic liquid crystal-wall interface using thin hybrid alignment nematic cell,” Jpn. J. Appl. Phys. 43, L649–L651 (2004).
[CrossRef]

Scheffer, T. J.

T. J. Scheffer and J. Nehring, “Accurate determination of liquid crystal tilt bias angles,” J. Appl. Phys. 48, 1783–1792 (1977).
[CrossRef]

Ting, C. L.

A. Y. G. Fuh, C. K. Liu, K. T. Cheng, C. L. Ting, and C. C. Chen, “Variable liquid crystal pretilt angles generated by photoalignment in homeotropically aligned azo dye-doped liquid crystals,” Appl. Phys. Lett. 95, 161104 (2009).
[CrossRef]

Uchida, T.

T. Ishinabe, Y. Ohno, T. Miyashita, and T. Uchida, “High-precision measurement of polar anchoring strength and elastic constant ratio using hybrid alignment nematic cell,” Jpn. J. Appl. Phys. 47, 8892–8897 (2008).
[CrossRef]

Appl. Phys. Lett.

A. Y. G. Fuh, C. K. Liu, K. T. Cheng, C. L. Ting, and C. C. Chen, “Variable liquid crystal pretilt angles generated by photoalignment in homeotropically aligned azo dye-doped liquid crystals,” Appl. Phys. Lett. 95, 161104 (2009).
[CrossRef]

J. Appl. Phys.

S. Matsumoto, M. Kawamoto, and K. Mizunoya, “Field‐induced deformation of hybrid‐aligned nematic liquid crystals: New multicolor liquid crystal display,” J. Appl. Phys. 47, 3842–3845 (1976).
[CrossRef]

T. J. Scheffer and J. Nehring, “Accurate determination of liquid crystal tilt bias angles,” J. Appl. Phys. 48, 1783–1792 (1977).
[CrossRef]

J. Display Technol.

Jpn. J. Appl. Phys.

L. T. Hung, S. Oka, M. Kimura, and T. Akahane, “Determination of polar anchoring strength at vertical alignment nematic liquid crystal-wall interface using thin hybrid alignment nematic cell,” Jpn. J. Appl. Phys. 43, L649–L651 (2004).
[CrossRef]

T. Ishinabe, Y. Ohno, T. Miyashita, and T. Uchida, “High-precision measurement of polar anchoring strength and elastic constant ratio using hybrid alignment nematic cell,” Jpn. J. Appl. Phys. 47, 8892–8897 (2008).
[CrossRef]

Opt. Express

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Figures (4)

Fig. 1.
Fig. 1.

Director profile of LC molecules in a HAN cell.

Fig. 2.
Fig. 2.

χ1 versus θ1 with θ2 as a parameter with φ1=40°.

Fig. 3.
Fig. 3.

χ3 versus θ1 with θ2 as a parameter with φ1=40° and φ2=50°. The inserted figure denotes phase retardation versus incident angle with θ1=5° and changing θ2 from 81° to 90°.

Fig. 4.
Fig. 4.

Experimental scheme to measure phase retardations of HAN cells.

Tables (7)

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Table 1. LC Parameters Used in the Calculations

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Table 2. Phase Retardations of HAN Cells at Different Incident Angles

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Table 3. Measured Pretilt Angles of HAN Cells and Vertically Aligned Cells

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Table 4. Phase Retardations of HAN cells at Different Incident Angles

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Table 5. Measured Pretilt Angles of HAN Cells and Homogenously Aligned Cells

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Table 6. Phase Retardations and Calculated Pretilt Angles for TAF-Aligned HAN Cell

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Table 7. Measured Cell Gaps of HAN Cells

Equations (6)

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

Γ=2πΔdλ[(no2ne2)sinθcosθn2sinφ+nonen2sin2φn2no2sin2φ],
n2=no2cos2θ+ne2sin2θ,Γtotal(d,θ1,θ2,φ)=θ1θ22πdλ(θ2θ1)[(no2ne2)sinθcosθn2sinφ+nonen2sin2φn2no2sin2φ]dθ.
χ1(θ1,θ2,±φ1)=Γtotal(θ1,θ2,φ1)Γtotal(θ1,θ2,φ1),
χ2(θ1,θ2,±φ2)=Γtotal(θ1,θ2,φ2)Γtotal(θ1,θ2,φ2).
χ3(θ1,θ2,±φ1,±φ2)=Γtotal(θ1,θ2,φ1)Γtotal(θ1,θ2,φ1)Γtotal(θ1,θ2,φ2),
χ4(θ1,θ2,±φ1,±φ2)=Γtotal(θ1,θ2,φ2)Γtotal(θ1,θ2,φ1)Γtotal(θ1,θ2,φ2).

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