Luminance Degradation Correction Using Dual Reference Pixels
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Solution Overview
Problem
Existing display devices face challenges in accurately detecting luminance degradation of effective pixels due to environmental conditions, as current methods are influenced by temperature and brightness, and require large, expensive luminance measuring devices or sensors with varying characteristics.
Innovation Solution
The implementation of a dual reference pixel system, where one pixel is driven to emit light at a predetermined luminance for degradation measurement and another at an initial state, allows for detection of luminance degradation without environmental influence, using a single luminance sensor to compare and correct luminance levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a luminance measuring device is used to detect the amount of luminance degradation of reference pixels, then measurement accuracy is improved, but device size and cost increase significantly
Solution Approach 1:
The patent creates a virtual copy of the reference pixel by driving a display pixel to emit light at a predetermined luminance level and using a luminance sensor to detect it. This virtual reference pixel allows degradation measurement without requiring physical reference pixels or complex measuring devices, resolving the contradiction between measurement accuracy and device complexity
Solution Approach 2:
The patent introduces a luminance sensor as an intermediary component that measures the actual luminance output of display pixels. This intermediary enables indirect measurement of luminance degradation through electrical signals rather than direct optical measurement, reducing device complexity while maintaining measurement capability
2Device complexity
If a luminance sensor with photodiode is used to detect luminance degradation, then device size is reduced, but detection accuracy deteriorates due to temperature characteristics and varying diode characteristics
Solution Approach 1:
The patent implements a feedback mechanism where the luminance sensor continuously monitors the actual luminance output and this information is fed back to the drive circuit. The drive circuit adjusts the drive signal to compensate for sensor variations and environmental factors, maintaining measurement accuracy despite using a simple photodiode-based sensor
Solution Approach 2:
The system uses itself to calibrate and validate the luminance sensor by driving pixels to known luminance levels and using the sensor readings to establish reference values. This self-calibration process compensates for sensor characteristics and environmental variations without requiring external calibration equipment
3Measurement precision
If reference pixels are driven continuously to monitor degradation, then degradation detection accuracy is improved, but power consumption increases
Solution Approach 1:
The patent implements periodic monitoring where the luminance sensor measures pixel luminance at specific intervals rather than continuously. The drive circuit activates reference pixels periodically to establish baseline luminance levels, then uses these periodic measurements to detect degradation trends, significantly reducing power consumption while maintaining detection accuracy
Solution Approach 2:
The patent performs preliminary calibration by driving pixels to predetermined luminance levels before normal operation to establish reference degradation curves. This preliminary action creates a baseline that enables passive degradation monitoring during normal display operation without requiring continuous active reference pixels
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 enables accurate detection and correction of luminance degradation in effective pixels, independent of environmental conditions, improving image quality and reducing the need for costly measurement devices.
Implementation Method 1
organic electroluminescence (EL) elements that utilize a phenomenon of emitting light when an electric field is applied to an organic thin film
Implementation Method 2
a luminance sensor including a photodiode or the like is generally used to detect the amount of luminance degradation of the reference pixels
Data Source
AI summary
A display device includes a first reference pixel section configured to be driven to emit light at a predetermined luminance, a second reference pixel section configured to be driven to emit light when an amount of luminance degradation is to be detected, and a correcting unit configured to correct luminance degradation of effective pixels that contribute to display on the basis of a detection result of luminances of the first reference pixel section and the second reference pixel section.