In December 2016 Patently Apple posted a report titled "Apple Filed another Update to their Video Headset back in August Describing Two Viewing Modes for iPhone." Apple noted in claim #1 of their continuation patent that "a display is configured to operate in one of a normal viewing mode and a close up viewing mode and wherein the display is configured to operate in the close up viewing mode when the cellular telephone is connected to a head-mounted device."Today a pair of technical patents regarding a possible future VR/AR headset focuses on dual scanning modes for the display was published by USPTO. One mode for high resolution and another for high refresh rates.
Apple's patent covers an electronic device may include a display such as a LED display. The electronic device may be a head-mounted device that provides a virtual reality or augmented reality environment to the user.
Displays may be provided with high resolution and may operate with high refresh rates. To reduce image artifacts in the display at high refresh rates, a display may be operable in both a normal scanning mode and a partial scanning mode.
In the normal scanning mode, every row of the display may be scanned in each frame.
In the partial scanning mode, only a subset of the rows of the display may be scanned in each frame. The display may have a higher refresh rate in the partial scanning mode than in the normal scanning mode.
By selectively disabling sections of the display during the partial scanning mode, display performance may be improved and power may be conserved. However, the display sections that are disabled during the partial scanning mode may experience less thin film transistor (TFT) stress than the display sections that are not disabled during the partial scanning mode.
Over time, this imbalance in TFT stress may cause visible artifacts in the display. To equalize the amount of permanent TFT stress in each section of the display, the scan driver of the sections that are disabled during the partial scanning mode may still scan the disabled rows during the partial scanning mode (even though the disabled rows do not display images).
Apple notes that scanning modes will be used in electronic devices such as a pair of eyeglasses (e.g., supporting frames), may form a housing having a helmet shape, or may have other configurations to help in mounting and securing the components of one or more displays on the head or near the eye of a user. The also mention a 'gaming device' which could explain the need for a high refresh rate mode.
Apple's patent FIG. 26 is a diagram showing a scanning scheme for performing a scan for the timing of incoming pixel data packets while using a scanning driver.
The good news is that the depth of this patent filing goes to show the depth of engineering Apple is putting into a future advanced headset. On the flip side, most of us earthlings really won't get what Apple is describing in-depth. Yet if you're an engineer, this could be an interesting read for you.