Konica Minolta, Inc.

Konica Minolta Opto, Inc.

Konical Minolta Advanced Layers, Inc.

Ayako Inagaki

Shigeki Oka

Takahiro Takagi

Yuki Kaneko

Takashi Sera

Kentaro Yano

Provided is an optical film which does not undergo the deterioration in front contrast or contrast fluctuations even when used in a VA-type liquid crystal display device having high front contrast or as a polarizing plate protection film. The optical film comprises a cellulose ester resin having high stretching adequacy and having an average acetyl group substitution degree of 2.0-2.6, has a phase difference (Ro) of 30-100 nm, a phase difference (Rth) of 70-400 nm and a film thickness of 15-50 &#x3bc;m, and is characterized by fulfilling a requirement represented by formula (I). Formula (I): 0.01&#x3c;S(bs)/S(T)&#x3c;0.30, in the formula, S(bs) represents the quantity of backscattered light at 590 nm and 25&#xb0;-85&#xb0; when the angle of incident light that enters the film is set at 0&#xb0;, the intensity of scattered light at 590 nm and 25&#xb0;-85&#xb0;; and S(T) represents the total quantity of incident light that enters the film.

Optical film, polarizing plate equipped with the optical film, process for manufacture of the polarizing plate, and liquid crystal display device

A vertical alignment mode liquid crystal display comprising: a liquid crystal cell; a first polarizer; a second polarizer; a first optical film arranged between the first polarizer and the liquid crystal cell; and a second optical film arranged between the liquid crystal cell and the second optical film, wherein the first and the second optical films each are a resin film having an optically biaxial property, the first and the second optical films meet: Formula (1) Ro&#x3e;Ro; Formula (2) Rth&#x3c;Rth; Formula (3) DSP&#x3c;DSP; and Formula (4) DSP&#x3c;DSP, wherein Roand Rorepresent in-plane retardation values of the first and the second optical films, respectively, Rthand Rthrepresent retardation values in the thickness direction of the first and the second optical films, respectively, and DSP, DSP, DSPand DSPrepresent wavelength dispersion properties of Ro, Ro; Rthand Rth, respectively.

Vertical alignment mode liquid crystal display

The purpose of the present invention is to provide: a retardation film which uses a low-substituted cellulose ester and has improved retardation after saponification and improved wet heat stability of internal haze; a polarizing plate which uses the retardation film; and a liquid crystal display device. An optical film of the present invention contains a cellulose ester and a compound represented by general formula (1), and is characterized in that the compound has an average degree of substitution within the range of 3.0-6.0 and contains a component having a degree of substitution of 4 or less in an amount of 30-80% by mass (inclusive). (In the formula, R-Reach represents a substituted or unsubstituted alkylcarbonyl group or a substituted or unsubstituted allylcarbonyl group, and R-Rmay be the same as or different from one another.) 

Retardation film, polarizing plate using same, and liquid crystal display device

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Tachikawa, Japan

Ayako Inagaki