OLED Illumination Aperture Ratio via Vertical Signal Routing
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Solution Overview
Problem
Conventional OLED illumination devices face a reduction in aperture ratio due to the presence of metal signal lines, which also lead to higher impedance and increased power consumption when attempting to divide the emitting area into sub-emitting areas for local dimming.
Innovation Solution
The design incorporates a transparent substrate with first metal lines connected to sub-emitting areas and a peripheral area, where the first metal lines overlap with second metal lines in a vertical projection, and a greater number of first metal lines are connected to farther sub-emitting areas than to closer ones, balancing electrical currents and signals for uniform illumination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the emitting area is divided into more sub-emitting areas to achieve local dimming, then the control precision is improved, but the aperture ratio is reduced due to more signal lines occupying emitting areas
Solution Approach 1:
The patent transitions from a two-dimensional planar layout to a three-dimensional stacked architecture. Signal lines are routed through the thickness direction of the substrate, allowing them to connect to sub-emitting areas without occupying lateral emitting area. This vertical routing resolves the contradiction by adding a dimensional degree of freedom for signal distribution.
Solution Approach 2:
The patent implements nested signal line configurations where signal lines are embedded within multiple layers of the substrate structure. Inner signal lines are surrounded by outer signal lines, and both are integrated within the substrate thickness. This nesting allows dense signal routing without increasing the lateral footprint, maintaining high aperture ratio while supporting fine-grained local dimming control.
2Area of stationary object
If the width of metal signal line is reduced to decrease occupying area, then the aperture ratio is improved, but the impedance increases and power consumption increases
Solution Approach 1:
The patent changes the geometric parameters of signal lines by routing them in the thickness direction rather than laterally. This parameter change allows the signal lines to have sufficient cross-sectional area for low impedance while occupying minimal lateral space. The effective width is maintained through vertical extension, resolving the contradiction between aperture ratio and power consumption.
Solution Approach 2:
The patent moves signal line routing from the lateral plane to the vertical dimension. By extending signal lines through the substrate thickness, the effective conductive cross-section is increased without lateral expansion. This dimensional transition maintains low impedance characteristics while minimizing the lateral footprint of signal lines.
Data Source
AI summary
An illumination device includes a transparent substrate and multiple first metal lines. The transparent substrate includes an emitting area and a peripheral area and the emitting area includes multiple sub-emitting areas. The first metal lines are disposed on the transparent substrate, each first metal line has an end connected to a corresponding one of the sub-emitting areas and an opposite end connected to the peripheral area. Each sub-emitting area includes an insulating layer, a second metal line and an OLED layer. The second metal line is disposed between the transparent substrate and the OLED layer, the insulating layer is between the first metal lines and the second metal line, each first metal line is overlapped with the second metal line in vertical projection. One of the first metal lines, which is connected to a first one of the sub-emitting areas, passes through a second one of the sub-emitting areas.