Luminance Correcting Unit for Organic EL Display Burn-In Compensation
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Solution Overview
Problem
Display apparatuses using organic EL display elements suffer from a decrease in luminance over time due to the burn-in phenomenon, which complicates control and requires storing historical data on image luminance, operating time, and temperature conditions to compensate for this decrease.
Innovation Solution
A display apparatus with a luminance correcting unit that calculates a reference operating time and uses a reference curve to adjust gradation values for each display element, compensating for temporal luminance variations without needing to store historical data on image luminance, operating time, and temperature conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If historical data on image luminance, operating time, and temperature conditions is stored to compensate for luminance decrease, then luminance compensation accuracy is improved, but device complexity and control difficulty increase
Solution Approach 1:
The patent extracts only the essential parameter (accumulated operating time) from the complex set of historical data (image luminance, operating time, temperature conditions), eliminating the need to store and process multiple data types while maintaining compensation accuracy
Solution Approach 2:
The patent transforms the compensation approach by changing from storing raw historical data to storing a derived parameter (accumulated reference operating time), which simplifies the control system while preserving the necessary information for luminance compensation
2Reliability
If historical data is stored to compensate for luminance decrease, then luminance compensation is improved, but data storage requirements and control complexity increase
Solution Approach 1:
The patent extracts only the essential temporal information needed for compensation, discarding unnecessary data about image luminance and temperature conditions, thereby reducing storage requirements while maintaining reliability
Solution Approach 2:
The patent performs preliminary calculation of the accumulated reference operating time during device operation, preparing the compensation data in advance so that no complex data storage and processing is needed during actual display operations
Data Source
AI summary
A display apparatus includes: a display panel that includes display elements having a current-driven light-emitting portion, in which the display elements are arranged in a two-dimensional matrix in a first direction and a second direction, and that displays an image on the basis of a video signal; and a luminance correcting unit that corrects the luminance of the display elements when displaying an image on the display panel by correcting a gradation value of an input signal and outputting the corrected input signal as the video signal. The luminance correcting unit includes a reference operating time calculator, an accumulated reference operating time storage, a reference curve storage, a gradation correction value holder, and a video signal generator.