摘要：

Dye-based polarizing filim.wherein, X represents a naphthyl group having 1 to 3 sulfo groups, Y represents a phenyl group having 1 to 2 sulfo groups, or a naphthyl group having 1 to 3 sulfo groups, X and Y optionally being substituted with at least one group selected from the group consisting of alkyl groups and alkoxy groups each having 1 to 6 carbon atoms, R1, R2 and R4 represent each independently a hydrogen atom, alkyl group or alkoxy group each having 1 to 6 carbon atoms, R3 represents an amino group or hydroxyl group, and Q1 and Q2 represent each independently a hydrogen atom, alkali metal, organic amine or ammonium. A polarizing film having uniformly low orthogonal transmittance in the wavelength range from 550 to 700 nm inclusive, and having excellent light resistance includes a dichroic dye containing a polyazo compound of the formula (I) and an azo compound of the formula (II): ...- Philadelphia, PA, US- (USPTO) - - The Patent Description & Claims data below is from USPTO Patent Application 20070275186, Dye-based polarizing filim.TECHNICAL FIELD [0001]The present invention relates to a dye-based polarizing film containing a polyazo compound. BACKGROUND TECHNOLOGY [0002]In-car displays such as car navigations and the like are used under environments irradiated with day light, and liquid crystal displays such as liquid crystal projectors, projection televisions and the like are used under environments irradiated with large light quantity, therefore, there are required polarizing films having excellent degree of polarization as in conventional films and, further, having excellent light resistance which shows little decrease in absorbance of a polarizing film even if irradiated for a long time with large light quantity under an environment of high temperature. [0003]The polarizing film is produced, for example, by allowing a polarizing film substrate of a stretched oriented polyvinyl alcohol-based film to contain iodine or dye as a polarization element. Such an iodine-based polarizing film is inferior in durability against heat, thus, has a problem of deterioration of light resistance under high temperature conditions. [0004]While, a dye-based polarizing film using a dye as a polarizer has more excellent durability against heat as compared with the iodine-based polarizing film, thus, used more and more recently. [0005]Specifically, Example 1 in Patent Document 1 discloses a polarizing film having a polarizing film substrate containing a compound of the formula (I-1) as a dye, and exemplifies that its .lamda.max (wavelength at which, when a polarizing film is irradiated with light, the transmittance of the light which is transmitted toward the orientation direction of the polarizing film is minimum. Applicable also in the following descriptions) gives 610 nm. Example 1 in Patent Document 2 discloses a polarizing film containing a compound of the formula (II-1) as a dye, and exemplifies that its .lamda.max gives 616 nm. [0006][Patent Document 1] Japanese Patent Application Laid-Open (JP-A) No. 2005-171231 Example 1 [0007][Patent Document 2] JP-A No. 6-122831 Example 1 DISCLOSURE OF THE INVENTION [0008]When two polarizing films are superimposed so that orientation directions thereof cross at right angle (cross position) and there is leakage of a light of specific wavelength in a visible wavelength range, if the polarizing films are installed on a liquid crystal display, then, display of liquid crystal shows discoloration by leakage of a light of specific wavelength in dark condition (shifting from neutral color (neutral gray)). To prevent such a phenomenon, transmittance in cross position (orthogonal transmittance) in the visible range, particularly, in the wavelength range from 550 nm to 700 nm should be uniformly lowered, in two polarizing films. [0009]Investigations by the present inventors have clarified that the orthogonal transmittance of a polarizing film having a polarizing film substrate containing only a compound (I-1) as a dichroic dye does not uniformly lower at from 550 to 700 nm, particularly at 700 nm

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