Reflective OLED Bus for Power Distribution and Lifetime
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Solution Overview
Problem
Existing OLED devices face limitations in power and signal distribution due to the size and conductivity of conductive busses, which affect the lifetime and efficiency of the materials, as increasing bus size improves distribution but reduces lifetime, and increasing emissive area size decreases current density, thereby reducing distribution effectiveness.
Innovation Solution
The implementation of a reflective, electrically-conductive bus that covers only a portion of the light-emissive area, allowing for increased emissive area size while reducing driving current density and improving lifetime, with the bus positioned adjacent to a transparent insulator layer and comprising reflective surfaces to direct and reflect light efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the size of conductive busses is increased to improve power and signal distribution, then the distribution effectiveness is improved, but the aperture ratio (emissive area) is reduced
Solution Approach 1:
The patent moves the conductive busses from the traditional plane between emissive areas to the backplane of the display device. This spatial repositioning allows busses to carry current without occupying the aperture space, effectively adding a dimensional solution (z-axis placement) to resolve the area conflict.
Solution Approach 2:
The patent introduces a transparent conductive oxide layer as an intermediary between the backplane and the emissive areas. This intermediate layer facilitates current distribution to the emissive areas without requiring opaque busses to block light, thus maintaining both distribution effectiveness and aperture ratio.
2Illumination intensity
If the current density is increased to improve light emission intensity, then the brightness is improved, but the OLED material lifetime is reduced
Solution Approach 1:
The patent segments the current distribution function by separating the high-current backplane busses from the low-current emissive area interfaces. The transparent conductive oxide acts as an intermediate distribution network, allowing high current to be delivered efficiently while maintaining low current density at the OLED material interface, thus extending lifetime.
3Duration of action of stationary object
If the emissive area size is increased to reduce current density and improve lifetime, then the aperture ratio is improved, but the power and signal distribution effectiveness is reduced
Solution Approach 1:
The backplane busses are designed to serve multiple functions: they provide mechanical support for the display structure, serve as the primary current distribution network, and act as a shield against external interference. This multi-functionality allows for optimized current distribution across large emissive areas without compromising structural integrity or distribution effectiveness.
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 solution enhances power and signal distribution in OLED devices, increasing the relative size of the emissive area and improving OLED lifetime by reducing current density and ensuring effective light emission without compromising material longevity.
Implementation Method 1
one or more reflective, electrically-conductive bus formed in a layer adjacent to the transparent insulator layer opposite the transparent electrode, wherein the reflective, electrically-conductive bus comprises a reflective surface directed towards the light-emitting layer
Data Source
AI summary
An organic light-emitting diode (OLED) device, comprising: a first electrode and a second electrode having one or more organic layers formed there-between, at least one organic layer being light-emitting, the first and second electrodes defining one or more light-emissive areas, at least one of the electrodes being transparent; a transparent insulator layer formed adjacent to the transparent electrode opposite the one or more organic layer(s); and one or more reflective, electrically-conductive bus formed in a layer adjacent to the transparent insulator layer opposite the transparent electrode, wherein the reflective, electrically-conductive bus comprises a reflective surface directed towards the light-emitting layer and covers only a portion of the light-emissive areas.