Development of Low-Retardation TAC Film for Protection Films of LCD's Polarizer

Nakayama, H.; Fukakagawa, Nobutaka; Nishiura, Yousuke; Yasuda, Tomokazu; Ito, Tadashi; Mihayashi, Keiji

doi:10.2494/photopolymer.19.169

Cited by 27 publications

(25 citation statements)

References 2 publications

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“…The chemical structure of the TAC is shown in Fig. 5, which has bulky, rigid main chain and bulky acetyl groups that give large intermolecular free volume [27]. The PVA layer is sandwiched between two TAC films, where the TAC prevents swelling and shrinking of the PVA and prevents the evaporation of iodine or dyes in the PVA when temperature and humidity of the polarizer film are changed.…”

Section: Polarizer Filmmentioning

confidence: 99%

Structure and application of polarizer film for thin-film-transistor liquid crystal displays

Jin

2011

Displays

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Section: Polarizer Filmmentioning

confidence: 99%

Structure and application of polarizer film for thin-film-transistor liquid crystal displays

Jin

2011

Displays

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“…Their research group also proposed that addition of rod-like crystals having strong optical anisotropy is effective to control the birefringence (Tagaya et al 2003;Ohkita et al 2004;Koike et al 2006). Nakayama et al (2006) prepared a zerobirefringence film using CTA, in which not only inplane but also out-of-plane birefringence, i.e., retardation in the thickness direction, was controlled. Zhou et al (2010) reported that cyclic block copolymer films prepared by melt-extrusion show significantly low level of retardation both in-plane and out-ofplane.…”

Section: Introductionmentioning

confidence: 98%

Material design of retardation films with extraordinary wavelength dispersion of orientation birefringence: a review

et al. 2012

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Orientation birefringence and its wavelength dispersion for various types of cellulose esters are reviewed. Cellulose esters such as cellulose acetate propionate and cellulose acetate butyrate show positive orientation birefringence with extraordinary wavelength dispersion, which is determined mainly by the ester groups rather than the main chains. The acetyl group provides negative orientation birefringence with strong ordinary wavelength dispersion, whereas the propionyl and butyryl groups give positive orientation birefringence with weak wavelength dispersion. Although all groups show ordinary wavelength dispersion, the summation of their orientation birefringences gives extraordinary dispersion. Moreover, the wavelength dispersion is dependent on the stretching ratio due to the difference in the orientation relaxation of each group. On the contrary, cellulose triacetate (CTA) shows negative birefringence with ordinary wavelength dispersion because it has no positive contribution. However, doping a plasticizer having positive orientation birefringence changes the orientation birefringence of CTA from negative to positive, and the wavelength dispersion from ordinary to extraordinary. This is attributed to the cooperative orientation of plasticizer molecules to the stretching direction with CTA chains, known as nematic interaction upon a hot drawing process.

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“…As is well known, not only cellulose acetate but also poly(vinyl alcohol) (PVOH) that is produced via saponification of poly(vinyl acetate) (PVAc) are both very important as film base for acting as optical devices to control the polarization state of light wave. For instance, in liquid crystal display (LCD) panels, PVOH is generally used as a basic component, polarizer, and triacetyl cellulose (TAC) is applied as a protection film of the polarizer (Nakayama et al 2006). Birefringence of TAC films sometimes raises imperfect optical compensation on LCD, giving rise to a color shift of oblique incidence and/or a worse contrast of black/white level (Nakayama et al 2006).…”

Section: Introductionmentioning

confidence: 99%

“…For instance, in liquid crystal display (LCD) panels, PVOH is generally used as a basic component, polarizer, and triacetyl cellulose (TAC) is applied as a protection film of the polarizer (Nakayama et al 2006). Birefringence of TAC films sometimes raises imperfect optical compensation on LCD, giving rise to a color shift of oblique incidence and/or a worse contrast of black/white level (Nakayama et al 2006). Therefore, in the present study, there is an element of developing a way of controlling optical properties of these materials, especially for selection, regulation, or compensation of linearly polarized light.…”

Section: Introductionmentioning

confidence: 99%

Molecular orientation and optical anisotropy in drawn films of cellulose diacetate-graft-PLLA: comparative investigation with poly(vinyl acetate-co-vinyl alcohol)-graft-PLLA

2011

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Cellulose diacetate-graft-poly(L-lactide) (CDA-g-PLLA) and poly(vinyl acetate-co-vinyl alcohol)-graft-PLLA (P(VAc-co-VOH)-g-PLLA) were synthesized over a range of compositions, by ringopening copolymerization of L-lactide at the original hydroxyl positions of the respective trunk polymers, CDA (acetyl DS = 2.15) and P(VAc-co-VOH)-g-PLLA (VAc = 64.2 mol%). All the products of both graft copolymer series were non-crystallizable and their solution-cast films showed no domain segregation of the two components that constituted the trunk and side-chains. A comparative study on the molecular orientation and optical anisotropy induced by uniaxial stretching of film samples was undertaken for the two copolymer series with various side-chain lengths. Overall behaviour of the orientation was estimated from the statistical second (\cos 2 x[) and fourth (\cos 4 x[) moments obtained by a fluorescence polarization method using a rod-like probe of *2.5 nm. Upon stretching, any film of both series imparted a positive orientation function, i.e., f = (3 \cos 2 x[ -1)/2 [ 0, which increased with the extent of deformation. The degree of molecular orientation was higher in the CDA-graft series with a semi-rigid trunk, and, in both series, it declined monotonically with increasing content of the PLLA side-chain. With regard to the optical anisotropy, CDA-g-PLLA films always exhibited a positive birefringence (Dn [ 0) upon stretching, while drawn films of P(VAc-co-VOH)-g-PLLA displayed a negative one. This contrast in polarity reflects a difference in the intrinsic birefringence between the two trunk polymers. Of interest was the finding of a discontinuous change in Dn value with copolymer composition (PLLA content) for the respective graft series, when compared at a given stage of elongation of the films. Discussion took into consideration the locally different orientation manners of the attached PLLA chain segments.

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Development of Low-Retardation TAC Film for Protection Films of LCD's Polarizer

Cited by 27 publications

References 2 publications

Structure and application of polarizer film for thin-film-transistor liquid crystal displays

Structure and application of polarizer film for thin-film-transistor liquid crystal displays

Material design of retardation films with extraordinary wavelength dispersion of orientation birefringence: a review

Molecular orientation and optical anisotropy in drawn films of cellulose diacetate-graft-PLLA: comparative investigation with poly(vinyl acetate-co-vinyl alcohol)-graft-PLLA

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