Apple illustrates a micro-LED Display for a Future Foldable Device in a Patent for Embedded Pixel Driver Chips
Yesterday Patently Apple discovered a patent application published in Europe with references back to its original U.S. filing that we didn't cover titled "Display with Embedded Pixel Driver Chips." Apple's embodiments relate to high resolution display panels and the technicalities of replacing TFT substrates in a display with a matrix of micro-LEDs on the microcontroller substrate.
Two out of the five inventors were previously with LuxVue, a micro-LED company that Apple acquired in May 2014. One of the inventors is the former Vice President of LuxVu Sandy (Hsin-Hua) Hu who is now listed on Linkedin as working at Apple with the title: micro-LED, MEMS, III-V & Silicon integration pioneer.
In general, Apple notes that conventional organic light emitting diode (OLED) or liquid crystal display (LCD) technologies feature a thin film transistor (TFT) substrate. More recently, it has been proposed to replace the TFT substrate with a matrix of microcontrollers bonded to the substrate and build a micro light emitting diode (LEDs) display by integrating a matrix of micro LEDs on the microcontroller substrate, in which each microcontroller is to switch and drive one or more micro LEDs.
Apple's invention covers a display integration scheme in which pixel driver chips are embedded face up in a display substrate. A front side redistribution layer (RDL) is formed over the pixel driver chips and insulator layer forming the display substrate, and the LEDs are placed on the front side RDL layer. This integration scheme may allow for significant freedom in designing and locating the pixel driver chips, which can be virtually any size. Conductive pillars can be formed through the insulating layer for connecting to chips that can be placed on a back side of the display substrate (e.g., power management IC, timing controller, processor, memory, etc.).
Covering this patent is to ensure that we have it on record to go along with the other three patents that we covered in 2019 regarding micro-LED displays (01, 02 & 03). More importantly, it's the first patent with a reference to micro-LED displays being used in connection with a foldable smartphone or other device.
Apple notes that patent FIG. 54, as illustrated below, is an isometric view illustration of a foldable display panel (#100) in accordance with an embodiment. FIG. 53 is a side view illustration of a curved or flexible display; and FIG. 55 is a top view illustration of a plurality of display panel tiles (#100) arranged side-by-side. In such a configuration, the tiles may be used together to form a larger screen or display area.
It should be noted that the illustration of a folding device is not part of a design patent but rather a utility patent which means it's only a generic figure illustrating a folding device which of course could end up being larger, wider, used as foldable iPhone, iPad or future foldable notebook.
Apple's patent application that was published in Europe on Friday showed a history back to U.S. patent application 20190096864 published in late May, 2019.
Unless you're a display engineer or the like, Apple's patent is highly technical and a difficult read. For engineers wishing to dive further into the heart of the patent covering "Display with Embedded Pixel Driver Chips," click here.
Considering that this is a patent application, the timing of such a product to market is unknown at this time.
Beyond Sandy Hu which we highlighted at the top of our report, the other inventors listed on the patent are as follows:
Edzer Huitema: Senior Manager Hardware Engineering at Apple. Previously worked a Polyera Corporation where he worked on flexible electronics and wearable devices.
Xia Li: Display Engineering Technologist. Previously worked at MC10 Inc. where he worked on digital tattoos, disposable biometrics using flexible, stretchable sensing patches.
Tore Nauta: Sr. Manager Hardware Engineer; previously worked at LuxVu
Vaibhav Patel: Engineering Manager. Previously worked at Qualcomm