Redundant OLED Pixel Circuit for Brightness and Defect Tolerance
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Solution Overview
Problem
Current display technologies face challenges in reducing power consumption and achieving high luminance emission, particularly in portable devices, where standard LEDs are inefficient in controlling light direction and assembly for smaller displays is not feasible.
Innovation Solution
A display design that includes a matrix of cells with up to three light emitting devices per cell, where only one device operates at a time, and a shared driving circuit reduces substrate area, allowing for higher pixel density and efficient light control using thin-film transistors and a redundancy scheme to handle defective devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If organic light emitting devices are used to achieve flexible and lightweight displays, then the display can be made thinner and more adaptable to curved surfaces, but the devices are susceptible to degradation from oxygen and moisture, requiring complex encapsulation structures
Solution Approach 1:
The encapsulation structure is divided into multiple discrete encapsulation units, each containing individual organic light emitting devices. This segmentation allows each device to be independently protected while maintaining the overall flexibility of the display structure.
Solution Approach 2:
The encapsulation units are arranged in a nested or layered configuration where multiple encapsulation layers protect the organic light emitting devices from different directions. This nested structure provides comprehensive protection against oxygen and moisture penetration while maintaining device flexibility.
2Area of stationary object
If multiple light emitting devices are arranged in a matrix to form display regions, then the display area and resolution are increased, but the complexity of the encapsulation structure increases to protect each device
Solution Approach 1:
The encapsulation units are designed as standardized, reusable modules that can be applied to each light emitting device in the matrix. This universal design allows the same encapsulation structure to protect multiple devices, reducing overall complexity despite the increased number of devices.
Solution Approach 2:
Adjacent encapsulation units share common boundary structures and support elements, merging protective functions across multiple devices. This combining approach reduces redundant encapsulation materials and simplifies the overall structure while maintaining protection for each individual device.
3Illumination intensity
If the display is divided into multiple display regions with different colors, then the color variety and visual quality are improved, but the manufacturing precision requirements increase for aligning the light emitting devices
Solution Approach 1:
Each encapsulation unit is specifically designed and optimized for its assigned color region (red, green, blue, or white). This local quality approach allows each device type to be independently manufactured and tested before assembly, reducing the alignment precision requirements during final assembly while maintaining overall color quality.
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 approach enables higher brightness levels with reduced power consumption, increased pixel density, and efficient light control, overcoming the limitations of standard LEDs in smaller displays by selectively operating multiple devices within each cell.
Implementation Method 1
Each light emitting device includes an organic light emitting device that emits light in response to application of a driving current
Data Source
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AI summary
An active matrix display where in one embodiment each cell comprises: a driving circuit for providing current to light emitting devices placed in the cell under the control of a data driver signal, a first light emitting device location connected to the driving circuit and a second light emitting device location connected in series to the first light emitting device location. A first thin-film transistor (TFT) is connected in parallel with the first light emitting device location and a second TFT is connected in parallel with the second light emitting device location, its gate node connected to the gate node of the first TFT. One terminal of a third TFT is connected to the gate nodes of the first and second TFTs and selectively connects a control signal to the first and second TFTs under the control of a scan driver signal. The control signal determines which of a first or second light emitting device placed in the cell emits light when the driving circuit provides current.