Konica Minolta, Inc.

Midori Kogure

Takatugu Suzuki

Rie Fujisawa

Kouji Tashiro

Rieko Ren

Norie Tanihara

Yukihito Nakazawa

Kenji Mishima

The retardation film has a slow axis with an angle of 10 to 80&#xb0; with respect to a longitudinal direction thereof and contains cellulose acylate having a degree of acyl substitution of 2.0 to 2.7 and a regulating agent. The retardation film has an in-plane retardation, measured at a wavelength of 550 nm, Ro550, of 115 to 260 nm. The retardation film has a &#x394;Ro is 3 to 30 nm, where &#x394;Ro is Ro550&#x2212;Ro450, where Ro450 is the in-plane retardation of the film measured at a wavelength of 450 nm. The retardation film without the regulating agent has an in plane retardation, measured at a wavelength of 550 nm, Rc550, and &#x394;Rc(Rc550&#x2212;Rc450) equal to or greater than 0, where Rc450 is the in-plane retardation measured a wavelength of 450 nm.

Retardation film, elongated circularly polarizing plate and organic EL display produced using said retardation film

A optical film includes a thermoplastic resin and a compound wherein: (1) the absorption spectrum of said compound in solution has at least two absorption maxima in the 200-350 nm wavelength range; (2) letting &#x3bb;max1 represent the wavelength of a first absorption maximum (one of the aforementioned absorption maxima) and letting &#x3bb;max2 represent the wavelength of a second absorption maximum (another of the aforementioned absorption maxima) at a shorter wavelength than the first absorption maximum, (&#x3bb;max1&#x2212;&#x3bb;max2) is at least 20 nm; (3) the aspect ratio of the molecules of the compound is at least 1.70; (4) each molecule of the compound has a non-aromatic hydrocarbon ring, a non-aromatic heterocycle, or an aromatic heterocycle; (5) the in-plane-retardation increase sensitivity of the compound is at least 0.1; 110 nm&#x2266;R(550)&#x2266;170 nm; 0.72&#x2266;R(450)/R(550)&#x2266;0.96; and 0.83&#x2266;R(550)/R(650)&#x2266;0.97.

Optical film, circularly polarizing plate, and image display device

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Kobe, Japan

Midori Kogure