1. Technical Field of the Invention
The present invention relates to a poly-azo compound, and a polarization film having said compound.
2. Description of the Related Art
Recently, there is a demand for further improvement in the degree of polarization of a polarization film. Further, displays mounted on automobiles such as car navigations and the like are used under environments for irradiation with day light and liquid crystal displays such as a liquid crystal projector, television for projection and the like are used under environments for irradiation with light of large quantity, therefore, there is required, for this application, a polarization film manifesting small decrease in the absorbance of the polarization film even under irradiation with light of large quantity under high temperature environments for a long period of time, namely, having excellent light resistance.
As the polarization film, there are known films containing a dye covering desired wavelength as a polarization element in a polarization film substrate such as a polyvinyl alcohol-based film oriented by streching, or a polyene-based film obtained by orientation to produce a polyene by de-hydrochloric acid of a polyvinyl chloride film or by dehydration of a polyvinyl alcohol film, and the like.
As the specific polarization element of a polarization film, there are known dyes containing a compound of the following formula (B) as an effective ingredient, however, the degree of polarization of a polarization film containing the dye is 98%, and light resistant is also insufficient (JP-A No. 5-295281, Example 63).

USPTO Backgrounds
USPTO Backgrounds