Achromatic dye-based polarization element, and polarization plate
AssigneesNippon Kayaku Kabushiki Kaisha, Polatechno Co., Ltd.
InventorNoriaki Mochizuki
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Abstract
A single body, which is a base material that contains a dichromatic dye formed from an azo compound, that exhibits transmissivity of equal to or greater than 35% and a polarization degree adjusted to equal to or greater than 99% and is characterized in that a* and b* values, which are acquired for a polarization element or a polarization plate using JIS⋅Z⋅8729, have an a* and b* absolute value that is: less than 1 at the time of a single-body transmittance measurement; less than 2 when two sheets of the base material are arranged parallel to the absorbing axis direction and the a* and b* values are measured; and less than 2 when two sheets of the base material are arranged orthogonal to the absorbing axis direction and the a* and b* values are measured.
Claims14
A polarization element comprising a stretched base material containing a dichroic dye that is an azo compound, wherein the polarization element is characterized in that:
- a* value and b* value of a hue calculated in accordance with JIS-Z-8729 are such that the absolute values of the a* value and the b* value when the single transmittance is measured are no more than 1, the absolute values of the a* value and the b* value measured with two of the base materials being arranged in parallel with respect to an absorption axis direction are no more than 2, and absolute values of the a* value and the b* value measured with two of the base materials being arranged orthogonally with respect to an absorption axis direction are no more than 2;
- the single transmittance is 35% or above, a polarization degree is 99% or above, and
- wherein said polarization element comprises a plurality of azo compounds, and wherein the plurality of azo compounds comprises an azo compound represented by formula (1) or a salt thereof, and an azo compound represented by formula (2) or a salt thereof:
- (wherein A1 represents a phenyl group or naphthyl group having a substituent group;
- R1 and R2 each independently represent a hydrogen atom, a lower alkyl group, a lower alkoxy group, a sulfo group, or a lower alkoxy group having a sulfo group;
- and X1 represents a phenylamino group optionally having a substituent group);
- (wherein A2 represents a phenyl group or naphthyl group having a substituent group;
- R3 represents a hydrogen atom, a lower alkyl group, a lower alkoxy group, a sulfo group, or a lower alkoxy group having a sulfo group;
- and X2 represents a phenylamino group optionally having a substituent group).
Dependencies are inferred from the claim text.