OLED Circuit Board Wiring Overlap Reduces Frame Region
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional active matrix organic electroluminescent (AM OLED) display devices have a limited opening ratio due to the formation of silicon-based TFTs with low light transmittance, leading to high power consumption and short product lifetime, and top emission OLEDs face voltage non-uniformity and high driving voltage due to high electric resistance in the second electrode made of materials like indium tin oxide.
Innovation Solution
A light-emitting circuit board design where the wiring connecting the second electrode to the external terminal overlaps with the driver circuit, reducing the frame region and allowing for uniform voltage application across the second electrode by forming off-pixel contacts at multiple positions, thereby reducing the frame region and enhancing display quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If silicon-based TFTs with low light transmittance are formed in each pixel, then active matrix driving is achieved with high luminance and long lifetime, but the opening ratio is limited and power consumption increases
Solution Approach 1:
The patent moves the driver circuit from the plane of the pixel array to a separate dimension by forming it on the back surface of the substrate. This allows the front surface to be fully dedicated to pixel regions, maximizing the opening ratio while maintaining AM driving capability through the relocated driver circuit that connects to pixel electrodes via through-substrate conductors.
Solution Approach 2:
The patent segments the display device into functionally separate regions: the front surface contains only pixel regions for light emission, while the back surface contains the driver circuit. This segmentation allows each region to be optimized independently - the front for light output and the back for driving functions - resolving the conflict between opening ratio and driver circuit requirements.
2Illumination intensity
If the second electrode is made of light-transmitting material like indium tin oxide for top emission OLEDs, then light can be emitted from the top, but voltage non-uniformity occurs due to high electric resistance
Solution Approach 1:
The patent introduces a low-resistance metal layer as an intermediary between the high-resistance transparent second electrode and the driver circuit. This metal layer acts as a voltage distribution network that compensates for the high resistance of the transparent electrode material, ensuring uniform voltage application across the electrode while maintaining light transmission properties.
3Reliability
If the wiring connecting the second electrode to the external terminal is formed separately from the driver circuit, then electrical connection is achieved, but the frame region increases reducing the display area
Solution Approach 1:
The patent merges the wiring function with the driver circuit by integrating both functions into a single structure on the back surface. The driver circuit traces simultaneously serve as both the driving circuitry and the connection wiring to external terminals, eliminating the need for separate wiring and minimizing the frame region while ensuring reliable electrical connections.
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 increases the opening ratio, reduces power consumption, and ensures uniform image display with high luminance by minimizing the frame region and addressing voltage non-uniformity issues in top emission OLEDs.
Implementation Method 1
The holes and the electrons, injected from the first electrode 10 and the second electrode 11, respectively, recombine in the light-emitting organic layer 12, and thereby the light-emitting organic layer 12 emits light.
Data Source
AI summary
The present invention provides a light-emitting circuit board and a light-emitting display device, which can reduce a frame region (a space between a side of the board and a pixel region) on a board. The light-emitting circuit board of the present invention is a light-emitting circuit board comprising: on a board, a plurality of pixels each including a first electrode, a light-emitting layer, and a second electrode, stacked in this order; a driver circuit; and an external terminal, wherein the driver circuit is connected to the external terminal; the second electrode of the pixel and the external terminal are connected to each other by a wiring through an off-pixel contact; and the wiring is disposed to overlap with at least part of the driver circuit.