Radial Common Electrode Division for Organic EL Display Voltage Drop
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Solution Overview
Problem
In organic electroluminescence (organic EL) display devices, the division of a common electrode into parallel areas leads to abnormal voltage drops at the center and periphery during image display, causing the shapes of the divided areas to be visually recognized, which affects image quality.
Innovation Solution
The common electrode is divided into radial areas, with each area being narrower at the center and wider at the periphery, and connected via a voltage switch circuit to a reference power supply or scanning circuit, allowing for efficient current distribution and minimizing voltage drops, while also functioning as scanning electrodes for touch detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the common electrode is divided into parallel areas, then the current distribution is simplified, but abnormal voltage drops occur at the center and periphery causing visible shapes that degrade image quality
Solution Approach 1:
The patent applies asymmetry by changing the common electrode division from parallel lines to radial lines extending from the center. This asymmetric radial configuration naturally addresses the voltage drop issue at center and periphery by providing shorter current paths from the center region where abnormal voltage drops occur, thereby eliminating visible electrode shapes while maintaining simplified current distribution
2Manufacturing precision
If the common electrode is divided into radial areas, then voltage drops are suppressed and image quality improves, but the device structure becomes more complex
Solution Approach 1:
The patent merges multiple functions into the radial division structure. The radial divisions serve both as current distribution paths for suppressing voltage drops and as scanning electrodes for touch detection. This consolidation achieves improved image quality without proportionally increasing device complexity, as the same structural elements perform multiple roles
3Measurement precision
If radial division is implemented, then touch detection precision is improved, but the manufacturing process becomes more difficult
Solution Approach 1:
The radial division structure serves universal purposes: it functions as both the common electrode for display operation and as the scanning electrode for touch detection. This multi-functionality allows touch detection precision to be improved without requiring separate dedicated scanning electrode structures, thereby avoiding excessive manufacturing complexity
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 suppresses voltage drops and prevents the shapes of the divided common electrodes from being visually recognized, resulting in high-quality images and precise touch position detection.
Implementation Method 1
A part of the plurality of driving lines and a part of the plurality of sensing lines are activated to perform rare scan, by which an approximate position at which the user has touched is detected
Implementation Method 2
When electrons are injected into the light-emitting layer from the cathode electrode and holes are injected into the light-emitting layer from the anode electrode, the electrons and the holes are recombined. Extra energy released by the recombination excites, and then deexcites, light-emitting molecules in the light-emitting layer. Thus, the light-emitting elements emit light.
Data Source
AI summary
Provided is a high image quality display device including a touch panel. A display device includes a substrate; a display region provided on the substrate, the display region including an array of a plurality of pixels each including at least one light-emitting element; a scanning line driving circuit; a video signal driving circuit; a common electrode commonly provided for the plurality of light-emitting elements, the common electrode being divided into a plurality of divided areas extending in a radial direction in the display region; and a voltage switch circuit connected with the plurality of divided areas of the common electrode, the voltage switch circuit selectively connecting each of the plurality of divided areas of the common electrode with a reference power supply circuit supplying a constant potential or a scanning circuit detecting a touch position in the display region.