Organic EL Display Temperature Compensation Circuit
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Solution Overview
Problem
Existing organic EL display devices face challenges in accurately compensating for variations in drive transistor characteristics due to temperature changes across the display panel, leading to luminance unevenness, and current monitoring methods become complex when temperature detection circuits are provided for each pixel circuit.
Innovation Solution
A display device configuration with temperature detection circuits arranged at intersections of data and scanning signal lines, where a temperature measurement circuit estimates temperature distribution and corrects current monitoring results to compensate for variations in pixel circuit characteristics, reducing the complexity of the display device configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temperature detection circuits are provided for each pixel circuit to accurately measure temperature, then temperature measurement precision is improved, but device complexity increases significantly
Solution Approach 1:
The display panel is divided into multiple temperature zones with temperature detection circuits arranged at regular intervals (e.g., every N rows or columns) rather than at every pixel circuit. This segmentation approach captures temperature distribution characteristics while reducing the total number of detection circuits, thus lowering device complexity while maintaining adequate measurement precision for compensation purposes.
Solution Approach 2:
The patent utilizes the existing pixel circuit structure and drive transistors to serve dual purposes: both driving the display and functioning as temperature detection circuits. By repurposing existing components rather than adding dedicated temperature sensors, the system achieves temperature measurement without significantly increasing device complexity.
2Measurement precision
If multiple temperature detection circuits are arranged across the display panel to capture temperature distribution, then temperature distribution detection accuracy is improved, but the configuration becomes complicated
Solution Approach 1:
Temperature detection circuits are strategically positioned at specific locations (intersections of signal lines, regular intervals) rather than uniformly distributed across all pixel circuits. This local quality approach places detection resources where they are most needed to capture temperature gradients, achieving accurate temperature distribution detection with minimal configuration complexity.
Solution Approach 2:
The temperature detection circuits are designed to perform multiple functions: they serve as both temperature sensors and display pixel circuits. This multi-functionality eliminates the need for separate dedicated temperature sensor circuits, thereby achieving temperature distribution detection without increasing configuration complexity.
3Measurement precision
If current monitoring is performed for each pixel circuit to compensate for drive transistor variations, then compensation accuracy is improved, but the system becomes more complex and harder to maintain
Solution Approach 1:
The patent combines current monitoring functionality with the existing drive transistor and pixel circuit structure. The drive transistor serves dual purposes: driving the display element and enabling current monitoring for compensation. By merging these functions rather than implementing separate monitoring circuits for each pixel, the system achieves compensation accuracy without excessive complexity.
Solution Approach 2:
The system implements feedback compensation where measured current values and temperature data are used to adjust and correct drive signals in real-time. This feedback mechanism compensates for drive transistor variations and temperature effects, improving compensation accuracy while using a unified control approach rather than complex individual circuit adjustments for each pixel.
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 allows for accurate compensation of drive transistor variations across the display panel, maintaining image quality while simplifying the device configuration by using fewer temperature detection circuits, effectively addressing temperature-related issues in current monitoring.
Implementation Method 1
a temperature measurement circuit to measure a current flowing through the temperature detecting transistor in each of the temperature detection circuits
Implementation Method 2
An organic EL display device is known as a thin, high-quality, and low-power display device
Data Source
AI summary
The present application discloses a current-driven display device that can perform accurate external compensation in consideration of a temperature distribution in a display panel while preventing the configuration from being complicated. A display portion of an organic EL display device is provided with a plurality of temperature detection circuits in addition to pixel circuits arranged in a matrix. A data-side drive circuit measures a current flowing through a transistor in each temperature detection circuit. A display control circuit obtains a temperature from the measured value based on a temperature characteristic of the transistor, estimates a temperature of each pixel circuit from the temperature, corrects a current value measured at the time of characteristic detection for a drive transistor of each pixel circuit considering the estimated temperature, and updates correction data for compensating for variations in the threshold voltage and gain of the drive transistor based on the corrected current value.