Cascaded OLED Pixel Structures for Threshold Voltage Compensation
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Solution Overview
Problem
Existing organic light emitting display devices face non-uniformity in pixel luminance due to threshold voltage variations in driving transistors, limiting display effectiveness and requiring increased thin film transistors and capacitors, which reduces pixel size and display quality.
Innovation Solution
The implementation of organic light emitting display devices with multiple organic light emitting structures of different colors, cascaded and insulated, connected to a pixel circuit that includes specific switching transistors and a capacitor for voltage compensation, allowing each pixel unit to display multiple colors and compensate for threshold voltage non-uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the number of thin film transistors and capacitors is increased to compensate for threshold voltage non-uniformity, then the display uniformity is improved, but the pixel size is reduced
Solution Approach 1:
The pixel circuit is divided into multiple sub-circuits, each responsible for driving a specific organic light emitting structure. This segmentation allows independent compensation of threshold voltage for each sub-pixel, improving display uniformity without requiring a single large compensation circuit that would reduce overall pixel size.
Solution Approach 2:
Multiple organic light emitting structures are arranged in a cascaded configuration within the pixel, utilizing vertical stacking or layered arrangement. This dimensional approach allows multiple light emitting elements to share common control lines and reduces the horizontal space required, maintaining larger pixel area while achieving multi-color display and improved uniformity.
2Manufacturing precision
If multiple organic light emitting structures are added to display multiple colors, then the display effect is improved, but the pixel circuit complexity increases
Solution Approach 1:
The pixel circuit is designed with multi-functional components that can control multiple organic light emitting structures. The switching transistors and capacitors are configured to serve multiple purposes: controlling different sub-pixels, compensating for threshold voltage, and managing current distribution, thereby reducing the need for separate dedicated circuits for each function.
Solution Approach 2:
Multiple organic light emitting structures are cascaded and share common control lines, power supply lines, and compensation components. By merging these elements, the circuit complexity is reduced compared to having completely independent circuits for each light emitting structure, while still achieving multi-color display capability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enhances display effectiveness by enabling each pixel unit to display a wider range of colors, improving image quality while maintaining a manageable device thickness, and effectively compensating for threshold voltage non-uniformity and drift.
Implementation Method 1
a voltage is applied between an anode and a cathode by a pixel circuit, holes in the anode and electrons in the cathode are composite at an organic light emitting layer to produce excitons; the excitons are migrated under the effect of electric fields to deliver energy to luminescent molecules in the light emitting layer and excite electrons in the luminescent molecules to leap from a stationary state to a an excitation state, and the excitation state energy produces photons through radiated leaping
Data Source
AI summary
There are provided an organic light emitting display device, a driving method thereof and a display apparatus. The organic light emitting display device includes an underlay substrate, and organic light emitting pixel units arranged in a matrix on the underlay substrate; wherein the respective organic light emitting units comprise at least two organic light emitting structures which have different light emitting colors, are disposed in cascades and insulated from each other, and a pixel circuit connected corresponding to the organic light emitting structures and configured to drive the organic light emitting structures to emit light. Since the respective organic light emitting pixel units comprise at least two organic light emitting structures which have different light emitting colors, are disposed in cascades, and are insulated from each other, when displaying, each organic light emitting pixel unit can display, in different frame pictures, grey scale effects of at least two colors according to applied signals. The display effect can be raised because each organic light emitting pixel unit can display more colors.