How Apple Squeezes Four Times the Number of Pixels into its New iPad Retina Display

Apple’s new iPad offers multiple enhancements, the most prominent of which – and clearly the focus of Apple’s marketing campaign – is the 2048 × 1536, 264 ppi retina display. The display has four times as many pixels as the iPad 2 display. Apple promotes the new display at length on its iPad Features page, including a graphically interesting video under “Breakthrough technology. For a breakthrough display.” explaining, “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 from the signals.”

If you didn’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 µm 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 quality—thus increasing aperture area.

Figure 1                      Conventional to SHA Pixel Design Comparison

Source: DisplaySearch TFT LCD Process Roadmap Report

Note: Image refers to VA type SHA pixel

SHA technology was pioneered by Sharp and JSR many years ago. Initially adoption was slow due to added process complexity, increased costs and yield challenges. However, as super high resolution displays for mobile applications have increased the importance of high transmission and low power consumption, SHA has now become a critical technology for manufacturing high quality LCDs. Already more than 25% of LCDs adopt SHA technology and that is likely to continue to grow in the future.

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