OLED Leakage Current Compensation via Temperature Sensing
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Solution Overview
Problem
Organic light emitting display apparatuses face deteriorated image quality due to leakage current variations caused by temperature changes, which are difficult to suppress and affect contrast ratio, color gamut, and white balance.
Innovation Solution
An organic light emitting display apparatus with a temperature-sensing controller that supplies compensation signals to sub-pixels to minimize leakage current through a common layer, maintaining image quality across varying temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a common layer is formed to cover the overall pixel area by a whole surface deposition method, then manufacturing convenience is improved, but leakage current between adjacent sub-pixels increases
Solution Approach 1:
An insulation layer is introduced as an intermediary between the common layer and adjacent sub-pixels to block leakage current. The insulation layer acts as a mediator that prevents harmful electrical current from spreading while maintaining the beneficial common layer structure for manufacturing convenience.
Solution Approach 2:
The common layer is segmented into separate regions corresponding to individual sub-pixels, with insulation layers positioned between them. This segmentation maintains the manufacturing advantages of a common layer while preventing leakage current by dividing the continuous conductive path into isolated sections.
2Reliability
If the common layer is made more conductive to improve OLED performance, then device performance is improved, but temperature-dependent leakage current increases
Solution Approach 1:
The insulation layer serves as a temperature-stable intermediary that blocks leakage current regardless of temperature changes. While the common layer's conductivity varies with temperature, the insulation layer maintains its blocking function, decoupling the performance optimization from the leakage current problem.
Solution Approach 2:
Different regions of the device are given different electrical properties: the common layer is made highly conductive in areas where it should conduct (within sub-pixels), while insulation layers are placed in areas where current blocking is needed (between sub-pixels). This local differentiation allows simultaneous optimization of performance and leakage prevention.
3Object-generated harmful factors
If insulation layers are added to block leakage current, then leakage current is reduced, but device complexity increases
Solution Approach 1:
The insulation layer is designed to perform multiple functions simultaneously: blocking leakage current between sub-pixels, maintaining electrical isolation, and serving as part of the overall device architecture. This multi-functionality justifies the added structural element by providing multiple benefits from a single component.
Solution Approach 2:
The insulation layer is merged with the common layer formation process, where both layers are deposited in sequence during the same manufacturing stage. This integration reduces process complexity despite adding a layer, as it eliminates the need for separate processing steps and aligns with existing manufacturing workflows.
4Manufacturing precision
If compensation signals are supplied to minimize leakage current, then image quality is maintained, but control circuit complexity increases
Solution Approach 1:
A feedback mechanism is implemented where the controller monitors temperature changes and automatically adjusts compensation signals to sub-pixels affected by leakage current. This feedback loop maintains image quality by dynamically counteracting temperature-induced leakage variations without requiring manual intervention or complex external control systems.
Solution Approach 2:
The controller changes electrical parameters (compensation signal voltage or current) based on temperature conditions to counteract leakage current effects. By adjusting these electrical parameters dynamically, the system maintains consistent image quality across different operating temperatures without adding mechanical or structural complexity.
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
The solution effectively compensates for leakage current variations, maintaining image quality and brightness across different temperatures, thereby improving contrast ratio and color accuracy.
Implementation Method 1
a sensor configured to sense a temperature and provide thermal information about a display apparatus to the controller
Implementation Method 2
a controller...supplied a first compensation signal to a plurality of sub-pixels based on the sensed temperature...and supplied a second compensation signal which is different from the first compensation signal
Data Source
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AI summary
An organic light emitting display apparatus comprises a thermal sensor configured to sense temperature and a controller including a first leakage current compensation unit configured to supply a first compensation signal to a plurality of sub-pixels based on the sensed temperature from the thermal sensor and a second leakage current compensation unit configured to supply a second compensation signal, which is different from the first compensation signal, wherein an amount of leakage current of the plurality of sub-pixels is compensated according to the sensed temperature, by the controller.