Dual-Substrate OLED Voltage Drop Mitigation
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Solution Overview
Problem
As organic light emitting display devices increase in size, the drop in driving voltage supplied to each pixel becomes more significant due to line resistance, leading to non-uniform luminance across the display.
Innovation Solution
The implementation of an organic light emitting display device design that includes a first substrate with intersecting data and gate lines, parallel driving power lines, and a cathode electrode layer connected in common, along with upper and lower driving power supply members and cathode connection parts, which simultaneously supply driving voltage to both sides of the driving power lines to minimize voltage drop.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the display device is enlarged in size, then the display area is increased, but the driving voltage drop becomes more significant
Solution Approach 1:
The display device is divided into a first substrate and a second substrate that are coupled together. The first substrate contains the pixel circuits and driving power lines, while the second substrate contains the common electrode layer. This segmentation allows the driving power lines to be shorter on the first substrate, reducing voltage drop, while the common electrode on the second substrate provides a low-resistance return path.
Solution Approach 2:
The invention transitions from a single-substrate structure to a dual-substrate three-dimensional structure. By stacking the first and second substrates and coupling them through side surfaces, the patent creates a vertical dimension that shortens the horizontal current path length, thereby reducing voltage drop across the display area.
2Area of stationary object
If the driving power line length is increased to cover larger display areas, then the display coverage is improved, but the line resistance increases
Solution Approach 1:
The display is segmented into two substrates with distinct functional layers. The first substrate handles pixel-level driving circuits and power lines, while the second substrate provides a common electrode. This segmentation reduces the length of high-current paths on the first substrate, minimizing voltage drop and improving voltage stability across large display areas.
Solution Approach 2:
The second substrate acts as an intermediary that carries the common electrode layer. This intermediary structure provides a low-resistance return path for current, effectively reducing the overall resistance of the power delivery system and improving voltage stability without requiring longer power lines on the first substrate.
3Device complexity
If a single substrate structure is used, then the device complexity is reduced, but the voltage uniformity across pixels deteriorates
Solution Approach 1:
The device is segmented into two substrates with specialized functions. The first substrate is optimized for pixel circuits and driving power lines, while the second substrate is optimized for the common electrode. This functional segmentation enables better voltage uniformity across pixels by reducing power line length and resistance, justifying the increased device complexity.
Solution Approach 2:
By moving to a dual-substrate three-dimensional structure, the patent achieves better voltage uniformity across pixels. The vertical stacking and side-surface coupling create shorter current paths and reduce the impact of line resistance, improving voltage uniformity despite the increased structural complexity compared to a single substrate.
Data Source
AI summary
An organic light emitting display device is discussed. The organic light emitting display device includes a first substrate including an active area that includes a plurality of pixels, and including upper, lower, left, and right inactive areas. The first substrate includes a plurality of data lines and a plurality of gate lines; a plurality of driving power lines; a cathode electrode layer; a plurality of driving power pads; a plurality of cathode connection parts provided in each of the left and right inactive areas; a first common driving power line; a second common driving power line; and a plurality of cathode power pads. Each of the first and second common driving power lines includes a plurality of divided common division lines. The plurality of driving power lines are grouped into a plurality of driving power line groups to be connected to a corresponding common division line.