A Monochromatic Black and White Supertwisted Nematic Liquid Crystal Display with a Single Cell and a Birefringent Film

Hirakata, Jun–ichi; Komura, Shinichi; Nagae, Yoshiharu; Kaneko, Eiji; Kinugawa, K.; Kando, Yasuhiko; Kawakami, Hideaki

doi:10.1143/jjap.30.682

Cited by 3 publications

(1 citation statement)

References 8 publications

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“…The compensator is one of the essential optical elements for improving the performance of STN-LCDs. Birefringent films such as polycarbonate (PC) sheets are often applied to STN-LCDs [1][2][3][4]. For reflective LCDs with a single polarizer, more than two combined PC sheets are generally applied [3,4], although the thickness and the complexity of the configuration increase in that case.…”

Section: Introductionmentioning

confidence: 99%

27.2: Twisted‐Nematic Compensator for Reflective Color NB‐STN‐LCDs with a Single Polarizer

Masaki

Uesaka

Kumagi

et al. 2001

Symp Digest of Tech Papers

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The performance of a reflective color NB-STN-LCD with a single polarizer in combination with a twisted-nematic compensator is discussed. In contrast to combined uniaxial retarder sheets, it is possible to create a display with a high contrast ratio using only a single sheet, which is one of the advantages of the twisted-nematic compensator. For optimizing the performance of the display, the dispersion of the birefringence was found to be essential as well as the twist angle and the retardation of the compensator.

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Section: Introductionmentioning

confidence: 99%

27.2: Twisted‐Nematic Compensator for Reflective Color NB‐STN‐LCDs with a Single Polarizer

Masaki

Uesaka

Kumagi

et al. 2001

Symp Digest of Tech Papers

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Polarization Analysis of a Black and White Supertwisted Nematic Liquid Crystal Display with Two Laminated Birefringent Films of Different Optical Axes

Hirakata¹,

Nagae²,

Kando

1993

Jpn. J. Appl. Phys.

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Film supertwisted nematic liquid crystal displays (F-STN-LCDs) with a single birefringent plastic film can be used for monochromatic black-and-white (B/W) LCDs, but their contrast ratio is inferior to that of Double layered (D-)STN-LCDs. By measuring the wavelength dependence of the ellipticity and azimuth in STN-LCDs, the F-STN cell conditions which increase the contrast ratio are obtained. The incident linearly polarized light needs to pass through the STN-LCDs without changing the state of its polarized light in all wavelength regions. Accordingly an optical compensating layer which has the same wavelength dependence for the ellipticity and azimuth as the driving STN cell, must be positioned between the polarizer and the driving STN cell. By laminating two birefringent films with different optical axes, the optical activity caused by the liquid crystal's twist structure is canceled, and the contrast ratio of the F-STN-LCDs increases from 10:1 to 20:1.

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Wavelength Characteristics of Birefringent Film Refractive Index Anisotropy for a Black and White Film Supertwisted Nematic Liquid Crystal Display with a High Contrast Ratio

Hirakata¹,

Nagae²,

Kikuchi

et al. 1995

Jpn. J. Appl. Phys.

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Film supertwisted nematic liquid crystal displays (F-STN-LCDs) with a single birefringent plastic film can be used for monochromatic black and white (B/W) LCDs, but their contrast ratio is inferior to that of double-layered (D-) STN-LCDs. We optimized the wavelength characteristics of the birefringent film refractive index anisotropy (Δn) through calculations and experiments to increase the contrast ratio of F-STN-LCDs. It was found that the wavelength characteristics of the Δn should be large at shorter wavelength regions and small at longer wavelengths. Moreover, the main axis in exit elliptical polarized light of the film must be crossed perpendicular to that of the STN-LC cell in all wavelength regions to obtain a high contrast ratio of the B/W F-STN-LCD.

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A Monochromatic Black and White Supertwisted Nematic Liquid Crystal Display with a Single Cell and a Birefringent Film

Cited by 3 publications

References 8 publications

27.2: Twisted‐Nematic Compensator for Reflective Color NB‐STN‐LCDs with a Single Polarizer

27.2: Twisted‐Nematic Compensator for Reflective Color NB‐STN‐LCDs with a Single Polarizer

Polarization Analysis of a Black and White Supertwisted Nematic Liquid Crystal Display with Two Laminated Birefringent Films of Different Optical Axes

Wavelength Characteristics of Birefringent Film Refractive Index Anisotropy for a Black and White Film Supertwisted Nematic Liquid Crystal Display with a High Contrast Ratio

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