Nitto-denko Corporation

Mitsubishi Chemical Corporation

Hiroshi Sumimura

Nao Murakami

Takashi Shimizu

Hiroyuki Hayashi

Shingo Namiki

Hisatoshi Uehara

Yuuichi Hirami

Takeharu Kitagawa

Kentarou Takeda

Hironori Yaginuma

Tadashi Kojima

An object of the present invention is to provide a retardation film excellent in various properties such as optical properties, heat resistance, mechanical properties, and reliability. The present invention relates to a retardation film containing a thermoplastic resin and composed of a single layer, in which the retardation film has a value of wavelength dispersion that is a ratio of retardations at a wavelength of 450 nm and at a wavelength of 550 nm being 0.75 or more and 0.92 or less; a birefringence at a wavelength of 550 nm and the wavelength dispersion satisfy a relationship of &#x394;n&#x2265;0.0140&#xd7;(R450/R550)&#x2212;0.0082; and a photoelastic coefficient is 25&#xd7;10Paor less.

Retardation film, circularly-polarizing plate, and image-displaying device

The retardation film of the present invention contains a resin having positive refractive index anisotropy and containing at least one bonding group of a carbonate bond and an ester bond and one or more structural units selected from the group consisting of a structural unit represented by the general formula (1) and a structural unit represented by the general formula (2), in which the value of wavelength dispersion (R450/R550) as a ratio of retardation R450 at a wavelength of 450 nm to retardation R550 at a wavelength of 550 nm is more than 0.5 and less than 1.0: (in formula (1) and formula (2), definitions of Rto Rare the same as in the description).

The retardation film of the present invention contains a thermoplastic resin and is constituted of a single layer. A value of wavelength dispersion (R450/R550) that is a ratio of a retardation R450 at a wavelength of 450 nm and a retardation R550 at a wavelength of 550 nm is 0.70 or more and 0.85 or less; and a photoelastic coefficient is 14&#xd7;10Paor less.

There is provided a thin polarizing plate with a retardation layer excellent in reworkability. A polarizing plate with a retardation layer according to the present invention includes: a polarizing plate including a polarizer and a protective layer on at least one side of the polarizer; a retardation layer; a first adhesive layer configured to bond the polarizing plate and the retardation layer; and a second adhesive layer arranged as an outermost layer on an opposite side of the retardation layer to the polarizing plate. An average linear expansion coefficient of the second adhesive layer when an ambient temperature is changed from &#x2212;150&#xb0; C. to 20&#xb0; C. is 38.0(&#xd7;10/&#xb0; C.) or more, and is larger than an average linear expansion coefficient of the first adhesive layer when an ambient temperature is changed from &#x2212;150&#xb0; C. to 20&#xb0; C.

Polarizing plate with a retardation layer and image display apparatus

There is provided a circularly polarizing plate capable of realizing a bendable display apparatus in which an excellent reflection hue is obtained and a color change due to bending is suppressed. A circularly polarizing plate according to the present invention is used in a bendable display apparatus. The circularly polarizing plate includes: a polarizer; and a retardation film arranged on one side of the polarizer. In-plane retardations of the retardation film satisfy a relationship of Re(450)&#x3c;Re(550)&#x3c;Re(650), and a slow axis direction of the retardation film is adjusted so as to form an angle of from 20&#xb0; to 70&#xb0; with respect to a bending direction of the display apparatus.

Growing community of inventors

Osaka, Japan

Hiroshi Sumimura