Display Device Luminance Correction Circuit Temperature Stress
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Solution Overview
Problem
Conventional display technologies fail to adequately correct display unevenness caused by environmental temperature stress, particularly in high-temperature environments like those encountered in vehicles, leading to inaccuracies in video signal correction and potential display issues such as burn-in and color drift.
Innovation Solution
A display device with a correction circuit that calculates and corrects input gradation values using an efficiency residual ratio, accounting for both current and temperature stress, to ensure accurate luminance adjustment and reduce display unevenness by independently calculating stress amounts due to current and environmental temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional video signal correction techniques are used, then display unevenness can be reduced under normal conditions, but correction precision deteriorates when operating in high temperature environments
Solution Approach 1:
The patent changes the correction parameters dynamically based on temperature conditions. The correction circuit includes a temperature stress calculator that determines temperature stress amounts, and an efficiency residual ratio calculator that updates the efficiency residual ratio according to both current stress and temperature stress. This allows the correction parameters to adapt to varying temperature environments, maintaining correction precision across different thermal conditions.
Solution Approach 2:
The patent implements a feedback mechanism where the efficiency residual ratio is continuously updated based on accumulated stress information. The efficiency residual ratio calculator uses feedback from the current stress calculator and temperature stress calculator to adjust the correction values in real-time, ensuring that the correction precision is maintained despite changing operational conditions including temperature variations.
2Device complexity
If video signal correction is applied without considering temperature stress, then the correction process remains simple, but display unevenness occurs under high temperature conditions
Solution Approach 1:
The patent segments the stress calculation into separate components: a current stress calculator that handles current-related stress and a temperature stress calculator that handles temperature-related stress. This segmentation allows each component to focus on specific aspects of stress, making the overall system more manageable while improving reliability. The separate calculation modules can independently process their respective stress types and contribute to the unified correction.
Solution Approach 2:
The correction circuit is designed with multi-functionality to handle both current stress and temperature stress within a single integrated system. The efficiency residual ratio calculator serves multiple purposes by incorporating both current stress and temperature stress into a unified correction approach, making the system universally applicable to various operating conditions without requiring separate correction mechanisms for each stress type.
3Manufacturing precision
If the efficiency residual ratio is updated using accumulated stress amounts from both current and temperature, then display unevenness is reduced, but the calculation process becomes more complex
Solution Approach 1:
The patent performs preliminary actions by pre-calculating and accumulating stress amounts before the final correction is applied. The current stress calculator and temperature stress calculator continuously accumulate stress data in advance, so that when the efficiency residual ratio needs to be updated, the necessary stress information is already ready. This preliminary accumulation reduces the computational burden during the actual correction process while maintaining high display uniformity.
Data Source
AI summary
A display device includes: a luminance converter which converts input gradation value into a corresponding target luminance value; a luminance correction calculator which calculates output gradation value from the target luminance value and calculates a corrected luminance value from the output gradation value, using an efficiency residual ratio which is an index representing the light-emitting element deterioration degree; a current stress calculator which converts current stress amount on the light-emitting element calculated from the corrected luminance value into current stress amount when reference current flows through the light-emitting element, and calculates the accumulated current stress amount; a temperature stress calculator which converts temperature stress amount on the light-emitting element under environmental temperature into temperature stress amount on the light-emitting element under reference temperature, and calculates the accumulated current stress amount; and an efficiency residual ratio calculator which updates the efficiency residual ratio, using the accumulated current and temperature stress amounts.