Variable Mobility Correction for OLED Driving Circuits
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing driving methods for organic electroluminescence light emitting sections in organic EL display apparatuses face challenges in optimizing the mobility correction process, leading to inadequate luminance control, with high current flow during white display and excessive or insufficient current during black display, resulting in deteriorated display quality.
Innovation Solution
A driving method that includes a driving circuit with a driving transistor, an image signal writing transistor, and a capacitor section, where a correction voltage based on the image signal is applied to optimize the mobility correction process, reducing the influence of the image signal on the mobility correction and allowing for precise luminance control by varying the potential difference between nodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional 5Tr/1C driving circuit is used with fixed mobility correction voltage, then the circuit structure remains simple, but the luminance control becomes inadequate due to image signal influence on mobility correction
Solution Approach 1:
The patent applies dynamics by making the mobility correction voltage variable rather than fixed. The correction voltage is dynamically adjusted based on the image signal voltage level, allowing the driving circuit to adapt to different display conditions (white/black/gray levels) and compensate for mobility variations effectively, thereby improving luminance control precision without requiring a fundamentally more complex circuit architecture.
Solution Approach 2:
The patent changes the parameter of correction voltage from a constant value to a variable value that depends on the image signal. By modifying the correction voltage parameter according to the image signal level (applying different voltages for white, black, and gray displays), the system achieves better mobility correction and luminance control while maintaining the existing 5Tr/1C circuit structure.
2Manufacturing precision
If the mobility correction voltage is increased to compensate for mobility variations, then the luminance uniformity improves, but the current flow during white display becomes excessive
Solution Approach 1:
The patent applies local quality by providing different correction voltages for different image signal conditions rather than using a single high correction voltage for all cases. The correction voltage is locally optimized based on the specific display requirement (white, black, or gray), ensuring adequate mobility correction only when needed while avoiding excessive current flow during white display where high correction is not necessary.
Solution Approach 2:
The patent changes the correction voltage parameter dynamically based on the image signal level. Instead of maintaining a constantly high correction voltage that causes excessive current, the system adjusts the correction voltage parameter to match the actual mobility variation needs, thereby achieving luminance uniformity without unnecessary power consumption during white display.
3Power
If the correction voltage is adjusted to reduce current during white display, then the power consumption decreases, but the luminance control precision deteriorates during black display
Solution Approach 1:
The patent applies dynamics by making the correction voltage adaptive to different display conditions. The system dynamically switches between different correction voltage levels based on whether white, black, or gray is being displayed, ensuring that power consumption is optimized during white display while maintaining adequate correction precision during black display through appropriate voltage selection.
Solution Approach 2:
The patent changes the correction voltage parameter based on the image signal level. By adjusting the correction voltage parameter to be lower during white display (reducing power consumption) and appropriately higher during black display (maintaining precision), the system resolves the contradiction between power efficiency and control precision across different display conditions.
4Manufacturing precision
If a fixed correction voltage is applied, then the driving circuit operation remains simple, but the dispersion of luminance due to mobility variations cannot be effectively reduced
Solution Approach 1:
The patent changes the correction voltage parameter from fixed to variable based on the image signal. This parameter change enables effective reduction of luminance dispersion caused by mobility variations, as the correction voltage is appropriately adjusted for different display conditions (white, black, gray), while the implementation leverages existing circuit components to maintain operational simplicity.
Solution Approach 2:
The patent applies dynamics by making the correction voltage adaptive rather than static. The dynamic adjustment of correction voltage based on image signal levels effectively compensates for mobility variations and reduces luminance dispersion, while the control mechanism utilizes existing circuit elements to avoid significantly complicating the driving circuit operation.
Data Source
AI summary
A driving method for an organic EL light emitting section is provided which achieves optimization of a mobility correction process for a transistor of a driving circuit in response to luminance. The light emitting section may include a driving circuit with a driving transistor, an image signal writing transistor and a capacitor section having a pair of electrodes (corresponding to a first node ND1 and a second node ND2). A variable correction voltage which relies upon an image signal voltage is applied to the first node ND1 and a voltage which is higher than a potential of the second node ND2 in a threshold voltage cancellation process is applied to the drain electrode of the driving transistor, between the threshold voltage cancellation process and a writing process, to raise the potential of the second node ND2 in response to a characteristic of the driving transistor.