Segmented Cathode Active Matrix EL Display for High Resolution
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Solution Overview
Problem
Current active-matrix electroluminescent (EL) displays face limitations in achieving high resolution without increasing the number of active matrix drive circuits, leading to reduced manufacturing yields and higher costs, as well as power consumption issues in providing multi-view and stereoscopic displays.
Innovation Solution
The implementation of an active-matrix EL display with a larger number of individually-addressable light-emitting elements than active-matrix circuits, utilizing a two-dimensional array of first electrodes and a one-dimensional array of second electrodes with power supply circuits and a controller to manage current flow and voltage distribution, allowing for higher resolution and reduced power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the number of active matrix circuits is increased to achieve higher resolution, then the display resolution is improved, but the manufacturing complexity and cost increase, and manufacturing yields decrease
Solution Approach 1:
The cathode is segmented into multiple independently addressable segments along the vertical direction, while the anode maintains a simple two-dimensional array structure. This segmentation allows multiple light-emitting elements sharing the same anode to be controlled through different cathode segments, effectively increasing the number of addressable pixels without proportionally increasing the number of drive circuits.
Solution Approach 2:
The invention introduces an additional addressing dimension by segmenting the cathode into multiple vertically arranged segments. This allows the display to address pixels not only through the horizontal and vertical positions of the anode islands but also through the vertical position of the cathode segments, thereby multiplying the effective resolution without adding proportional circuit complexity.
2Manufacturing precision
If passive matrix displays are made large or high resolution, then the display size and resolution are improved, but power losses increase significantly due to capacitance
Solution Approach 1:
The invention employs active matrix drive circuits that dynamically control the current to each light-emitting element through transistor switching. This dynamic control allows for precise current management and reduces the continuous power loss associated with passive matrix displays, especially in large or high-resolution configurations where capacitance effects are significant.
3Manufacturing precision
If the number of transistors is increased to achieve higher resolution active matrix displays, then the display resolution is improved, but the likelihood of defects increases and manufacturing yields decrease
Solution Approach 1:
By segmenting the cathode into multiple independently controllable segments, the invention reduces the number of transistors required per pixel compared to a fully active matrix implementation. Each cathode segment can be controlled by shared drive circuits, reducing the overall transistor count while maintaining high effective resolution through the additional addressing dimension.
4Adaptability or versatility
If optical lenses are added to direct light into different viewing angles, then multi-view and stereoscopic capabilities are enabled, but the device complexity and manufacturing cost increase
Solution Approach 1:
The cathode is segmented into multiple vertically arranged segments that can be independently controlled to direct light into different viewing angles. By activating specific cathode segments, the display can present different images to different vertical viewing zones, enabling multi-view and stereoscopic capabilities without requiring complex optical lenses or barriers.
Solution Approach 2:
The invention replaces the mechanical/optical approach of using lenses or barriers to achieve multi-view capability with an electrical control approach. By selectively activating different cathode segments through electronic control, the display directs light into different viewing angles without requiring physical optical elements, thereby reducing device complexity and manufacturing cost.
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 the perceived resolution of the display by integrating light from multiple active areas, reducing power consumption, and enabling efficient operation in high-resolution and multi-view applications without the need for additional drive circuits, thus improving manufacturing yields and reducing costs.
Implementation Method 1
An electroluminescent light-emitting layer is formed between and in electrical contact with the first electrode and each of the second electrodes, the light-emitting layer emitting light in response to a current between the first electrode and each respective second electrode
Data Source
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AI summary
An active-matrix electroluminescent display including a display substrate (4); a first electrode (6) disposed over the display substrate; two second electrodes (14, 16) disposed over the first electrode; an electroluminescent light-emitting layer formed between and in electrical contact with the first and second electrodes, so that first and second active areas are defined where the first electrode and each respective second electrode overlap, the light-emitting layer emitting light from each active area in response to current between the first and each respective second electrode; a drive circuit including a drive transistor electrically connected to the first electrode for controlling the flow of current through the electroluminescent light-emitting layer; two power supply circuits connected to respective second electrodes for selectively providing respective voltages to the respective second electrodes; and a controller for sequentially or simultaneously causing the power supply circuits to provide the voltages to the respective second electrodes.