When you squeeze four times the pixels into the same space, signals can get crossed, colors become distorted and images get fuzzy. To solve this we had to elevate the pixels onto a different plane and separate them from the signals.
If you didnâ€™t catch what Apple means by that, they are referring to SHA (Super High Aperture) pixel designs. SHA is a method of increasing aperture ratio by applying approximately a 3 Âµm thick photo-definable acrylic resin layer to planarize the device and increase the vertical gap between the ITO pixel electrodes and signal lines. As we explained in our TFT LCD Process Roadmap Report, this reduces unwanted capacitive coupling and enables the electrode to be extended over the gate and data lines without causing cross talk or affecting image qualityâ€”thus increasing aperture area.