Organic EL Display Temperature Compensation via Dual-Element Sub-Pixels
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Solution Overview
Problem
The existing organic EL display devices face a reduction in display quality due to temperature changes, primarily because the pixel portions for temperature detection have a smaller light emission area than those for image display, leading to variations in luminance and potential degradation in display quality.
Innovation Solution
The organic EL display device incorporates sub-pixels with both a first organic EL element for image display and a second organic EL element for temperature detection, utilizing a temperature information detector to measure current-voltage characteristics of the second organic EL element and correct the driving signal of the first organic EL element based on the detected temperature information, ensuring uniform temperature dependencies across all sub-pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If pixel portions for temperature detection are added to the display device, then temperature detection capability is improved, but the light emission area of those pixel portions is reduced leading to luminance variations
Solution Approach 1:
The patent extracts the temperature detection function from dedicated pixel portions and implements it using the existing organic EL elements that are already part of the display structure. By measuring current-voltage characteristics of the organic EL elements, temperature information is obtained without requiring separate sensor pixels, thus avoiding the luminance variation problem while maintaining temperature detection capability
Solution Approach 2:
The organic EL elements serve dual functions: they act as both display elements for image output and as temperature sensors for thermal detection. By utilizing the inherent temperature-dependent electrical characteristics of the organic EL materials, the same structure performs both display and sensing functions, eliminating the need for separate sensor regions
2Device complexity
If temperature detection is implemented using existing pixel structures, then device complexity is reduced, but measurement precision of temperature information may be insufficient
Solution Approach 1:
The patent implements a feedback mechanism where temperature information is continuously obtained by measuring the current-voltage characteristics of the organic EL elements, and this temperature information is used to correct the driving signals. The correction unit adjusts the driving signals based on detected temperature variations, creating a closed-loop system that maintains display quality across different temperature conditions
Solution Approach 2:
The patent utilizes the temperature-dependent electrical parameters (current-voltage characteristics) of the organic EL elements as the basis for temperature detection. By monitoring changes in these electrical parameters with temperature, accurate temperature information can be extracted without additional hardware, and the driving signals are adjusted based on these parameter changes to compensate for temperature effects
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 effectively suppresses the reduction in display quality caused by temperature changes, maintaining high display quality by ensuring accurate temperature compensation and uniform luminance across the display device.
Implementation Method 1
a storage unit configured to store data regarding temperature dependency of current-voltage characteristics of the second organic EL element included in each of the sub-pixels, and a detection unit configured to detect, on the basis of the stored data, temperature information of the second organic EL element
Data Source
AI summary
An organic EL display device includes a plurality of sub-pixels each including a first organic EL element and a second organic EL element, a temperature information detector configured to measure current-voltage characteristics of the second organic EL element included in each of the sub-pixels, and to detect, on the basis of a result of the measurement, temperature information of the second organic EL element included in each of the sub-pixels, and a correction unit configured to correct a driving signal of the first organic EL element included in each of the sub-pixels on the basis of the temperature information of the second organic EL element included in the same sub-pixel as the sub-pixel including the relevant first organic EL element.