A brightness-enhanced and low color shift optical film with micro-prism for LCD and OLED

Liquid crystal materials don't emit light, and its phase difference is connections with viewing angle. In general, the brightness of liquid crystal displays (LCD) is limited and the color shift apparently exists at large viewing angles. Furthermore, the same problem is also emerged in organic light emitting diode (OLED) displays. Microcavity resonance effect in OLED seriously affects the luminance and brings about "blue shift" as viewing angle increases. We propose an optical film with micro-prism to improve the viewing angle characteristics of LCD and OLED, which can increase the brightness and decrease the color shift. Excellent agreements supported by simulations and experiments are obtained. The proposed optical film is coated on a 75in. 8K (7680×4320) LCD to measure the optical parameters. When the viewing (polar) angle is between ±60° and a white pattern is displayed, the maximum color shift Δμ'v' can be decreased from 0.027 to 0.006 after the proposed optical film is introduced. Moreover, the brightness at large viewing angles is enhanced obviously, both theoretical and experimental results are proved that the luminance is about 5%~40% higher than previous when the viewing angle ranges from 30° to 60° correspondingly.