Light control using vertically aligned dichroic dye films for windshield antireflection in automotive displays

Abstract

A vertically aligned dichroic dye (VA-Dye) film, whose absorption axis is perpendicular to that of its substrates, was laminated on a display panel in which the absorption axis of the top polarizer was set to 0°. In the vertical viewing angle of the display panel, the absorption axes of the top polarizer and dichroic dye are at right angles to each other, and, so, the light emitted from the display panel can be blocked. In the horizontal viewing angle of the display panel, the absorption axes of the top polarizer and dichroic dye are parallel to each other so that the light emitted from the display panel can be transmitted. Based on these polarization optics, we achieved complete elimination of light emitted in the upward or downward direction of the display panel, while the light emitted to the left and right is transmitted. We also added a designed optical compensation film using a positive biaxial ( + B ) retarder to the VA-Dye film so that the light emitted in the upward and downward directions of the display panel could be blocked in a wide viewing angle range (not only in the vertical direction, but also in the diagonal direction). The display panel using the VA-Dye film with the + B retarder showed excellent optical performance, such as significantly lower transmittance over a wide viewing angle range in the upward direction and relatively higher transmittance compared to that of a reference panel without the VA-Dye film. In addition, the VA-Dye film can be manufactured with a lower thickness, easier fabrication, and lower cost when compared with other technologies.