Retardation plate and circularly polarizing plate

Abstract

Provided is a retardation plate formed by laminating at least two retardation plates, being a retardation plate 1 and a retardation plate 2, wherein at least one of the retardation plate 1 and the retardation plate 2 is formed from a polymer of a polymerizable liquid crystal composition, and the retardation Re(450), at a wavelength of 450 nm, and the retardation Re(550), at a wavelength of 550 nm, of the retardation plate 1 and the retardation plate 2 have a predetermined relationship. Also provided are a circularly polarizing plate formed by laminating a polarizing plate on the retardation plate, and a display element or a light-emitting element comprising the circularly polarizing plate. The present invention is useful because with the present invention, it is possible to provide: a retardation plate that imparts a retardation of 1 / 4 wavelength over a wide wavelength range; a circularly polarizing plate having an excellent antireflection ability over a wide wavelength range; and a display element or a light-emitting element having excellent visibility.

Description

technical field [0001] The present invention relates to a retardation plate that imparts a phase difference of 1 / 4 wavelength over a wide wavelength range, a circular polarizing plate that is excellent in antireflection performance over a wide wavelength range, and a display element or a light emitting element that is excellent in visibility. Background technique [0002] Conventionally, in the case of a 1 / 4 wavelength plate including a single retardation plate, the wavelength that imparts a phase difference of 1 / 4 wavelength is limited to a specific wavelength, so it is used as an antireflection film for suppressing surface reflection of a display or the like. However, in the case of use, sufficient antireflection performance cannot be obtained at wavelengths other than the vicinity of a specific wavelength that imparts a phase difference of 1 / 4 wavelength, and the display is colored blue, purple, red, etc., and poor visibility is a problem. [0003] To solve this problem, ...

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Problems solved by technology

[0004] However, for any of the retardation plates of Patent Documents 1 to 3, the width of the wavelength region for imparting a retardation of 1 / 4 wavelength is not sufficient, and when a polarizing plate is laminated on the retardation plate to make circularly polarized light In the case of a plate, the width of the wavelength region that imparts excellent antireflection performance is not enough, so the improvement of the visibility of a display including a retardation plate or a circular polarizing plate is not enough.

Specifically, there is a problem that when viewing a display or the like from an oblique direction, a small amount of reflected light that cannot be completely prevented is inevitably generated, and this small amount of reflected light is not achromatic but colored in blue, purple, red, etc. thus visible

[0005] Furthermore, in any of Patent Documents 1 to 3, since the stretched film with a film thickness of several tens of μm is laminated, the thickness of the laminated phase difference plate becomes 150 to 200 μm, and there is a phase difference in displays such as displays that are often required to be thinner. The thickness of the poor board is too thick

[0006] Moreover, in Patent Documents 1 to 3, all of the stretched films whose slow axis is fixed in the stretching direction are used, so the slow axis of the retardation plate and the transmission axis of the polarizing plate are laminated so that the slow axis of the retardation plate and the polarizing plate are laminated. In the process, there is also the problem that the single-chip method with poor production efficiency must be used.

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