RELATED APPLICATIONS

This application claims priority to European Patent Application No. EP20159853.9 filed Feb. 27, 2020, which is incorporated herein by reference.

BACKGROUND

Field

Embodiments described herein relate to a display system, and more particularly to local active matrix displays and methods of operation.

Background Information

Display panels are utilized in a wide range of electronic devices. Common types of display panels include active matrix display panels where each pixel element, e.g. light emitting diode (LED), may be individually driven to display a data frame, and passive matrix display panels where rows and columns of pixel elements may be driven in a data frame. Frame rate can be tied to display artifacts and may be set at a specified level based on display application.

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 an array of pixel driver chips (also referred to as micro driver chips, or microcontroller chips) bonded to a substrate and integrate an array of micro LEDs (μLEDs) with the array of pixel driver chips, where each pixel driver chip is to switch and drive a corresponding plurality of the micro LEDs. Such micro LED displays can be arranged for either active matrix or passive matrix addressing.

In one implementation described in U.S. Publication No. 2019/0347985 a local passive matrix (LPM) display includes an arrangement of pixel driver chips and LEDs in which each pixel driver chip is coupled with an LPM group of LEDs arranged in display rows and columns. In operation global data signals are transmitted to the pixel driver chip, and each display row of LEDs in the LPM group is driven by the pixel driver chip one display row at a time.

SUMMARY

Local active matrix architectures including display panel stack-ups, circuits and methods of operation are described. In an embodiment, a local active matrix display panel includes an array of pixel driver chips, a thin film transistor layer over and in electrical contact with the array of pixel driver chips, and an array of light emitting diodes on the thin film transistor layer. Each pixel driver chip may be electrically connected to a corresponding matrix of LEDs and corresponding local pixel circuit matrix in the TFT layer. In operation, the pixel driver chips provide local matrix digital driving capability, while the TFT layer provides sample-and-hold and current source capability per sub-pixel. Such an arrangement may maximize emission duty cycle irrespective of LED matrix size and facilitate operation of the display panel at high multiplexing ratios.

