The U.S. Patent and Trademark Office on Thursday published an Apple patent application for an OLED display that uses built-in detectors to dynamically adjust output at select areas of the screen, comUsing data from photodiodes, a controller can detect variations in emitted light under various conditions. For example, ambient light information can be collected by the photodiodes. If a display area is dim, denoting a darker environment, the controller can adjust output accordingly. Because the sensors are part of the display rather than adjacent to it, as is the case with the ambient light sensor in the iPhone and iPad, the data is much more accurate. The patent takes into account that, in many cases, a single light measurement isn't enough. For example, a single ambient light sensor would be insufficient to detect a situation in which part of a screen is shaded, while the rest of the display is being hit by direct sunlight. With photodiodes, the shaded zone can be driven with less power than the unshaded area. The patent notes that photodiodes can also gather information about individual OLEDs or pixel groupings, measuring their output against a reference signal or other OLEDs with known outputs. If an OLED is determined to be aged and is no longer reproducing colors or brightness in concert with surrounding diodes, the controller can drive that specific component at a different strength to compensate.
The inclusion of photodiodes can also be used to make the display more useful. For example, the system can take the place of current proximity sensors, creating space for additional components. In one embodiment, the patent application notes that photodiode-equipped screen may only shut off those OLEDs that are directly obscured by a user when the device is up to their ear, leaving the rest active.
