On Thursday the US Patent & Trademark Office published two patent applications from Apple relating to larger Apple Watch interfaces that appear smoother on curved edges and an anti-burn-in solution for OLED displays.
Pixel Array Antialiasing to Accommodate Curved Display Edges
Apple notes in this patent application that a display may have one or more curved edges. For example, the display may have curved edges associated with rounded corners in the housing. The display may have an array of pixels with jagged edges along the curved edges.
The display may include full-strength pixels and may have a band of antialiasing pixels having selectively reduced strengths relative to the full-strength pixels. The antialiasing pixels may be provided with a pattern of strengths that visually smooth content displayed along the curved edges.
The pixels may be organic light-emitting diode pixels, liquid crystal display pixels, or other display pixels. Organic light-emitting diode pixels may have drive transistors and associated organic light-emitting diodes. The strength of the antialiasing pixels may be selectively reduced by modifying drive transistor geometry, adding series resistances, or by forming opaque light blocking structures that selectively limit the amount of light emitted by the organic light-emitting diodes. Liquid crystal display pixels may include electrodes of different shapes and/or opaque layer openings of different sizes to form antialiasing pixels with reduced strengths.
According to Apple, “hardware-based antialiasing techniques may be used to smooth the appearance of images along the curved edges of display 14 in FIG. 3 below.
In particular, the strengths of pixels along the curved edges may be arranged in an antialiasing pattern that visually smooths content that is displayed on the display along the curved edge and reduces undesired jagged image artifacts.
Apple’s patent FIG. 1 is a perspective view of an illustrative electronic device (Apple Watch); FIG. 3 is a diagram of an illustrative curved edge of a pixel array in a display.
Apple’s patent application may, in the end, be coming to market in Apple Watch Series 4 if 9to5Mac’s posted photo on Thursday actually launches in September.
Hall had noted that “The biggest change is the all-new edge-to-edge display. Apple has been rumored to be working on ~15% bigger displays for both sizes of Apple Watch.” Hall added that it appears that “Apple has achieved this by dramatically reducing the bezel size around the watch display.”
Like all patents, Apple doesn’t restrict their invention to the Apple Watch, which is shown to be the preferred device in this invention. Apple notes that it could apply to any iDevice, a device embedded in eyeglasses, a head mounted display, a display in a vehicle and more.
Apple’s patent application 20180246363 titled “Pixel Array Antialiasing to Accommodate Curved Display Edges,” was filed back in Q2 2018. Parts of this invention dates back to at least 2016.
It should also be noted that Apple was granted a patent in April 2018 covering both round and curved display advancements for a future Apple Watch interface.
Considering that this is a patent application, the timing of such a product to market is unknown at this time.
Compression Techniques for Burn-In on OLED Displays
Apple notes in their patent filing that new compression challenges are arising as computing device capabilities are improved through hardware and software advancements. For example, organic light-emitting diode (OLED) displays–which are becoming a popular choice for computing device displays–can degrade in a non-uniform manner over their lifespans and lead to unwanted color/brightness artifacts.
To address this concern, burn-in statistics–which record historical usage information associated with a given OLED display–can be used to artificially adjust the operation of the OLED display to substantially restore visual uniformity throughout its operation.
It is also desirable to store the burn-in statistics in a more efficient manner.
Apple’s invention covers techniques for compressing high-resolution, multiple-channel images that store burn-in statistics for display devices. In particular, the techniques involve pre-processing the images (i.e., prior to compression) in a manner that can enhance resulting compression ratios when the images are compressed using lossless compressors.
After a plurality of pixels are quantized, the method involves performing a series of operations against each modified pixel of the plurality of modified pixels.
In particular, a first operation involves applying an invertible transformation to the at least two sub-pixel values for the modified pixel to produce an equal number of transformed sub-pixel values.
A second operation involves applying a predictive coding to at least one of the transformed sub-pixel values of the modified pixel, where applying the predictive coding involves establishing a differential value by subtracting a corresponding and previously-processed sub-pixel value from the at least one of the transformed sub-pixel values.
A third operation involves encoding the differential value into two corresponding bytes, and encoding each of the other transformed sub-pixel values (different from the at least one of the transformed sub-pixel values) into respective two corresponding bytes.
A fourth operation involves serially storing the corresponding bytes as a data stream into a buffer.
Finally, a fifth operation involves compressing the data stream in the buffer, where the outputs of the compressed data streams for each of the modified pixels are continuously joined together to produce a compressed image.
Apple’s patent FIG. 1 illustrates an overview / flowchart of a computing device that can be configured to perform various techniques as it relates to the current invention to safeguard against OLED display burn-in.
Apple makes reference in their filing that their invention relates to OLED displays for iPhones, iPads and Apple Watch.
Apple’s patent application 20180247589 was filed in August 2017 and published this week by the U.S. Patent and Trademark Office.
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