Display Device Current Control for Luminance Uniformity
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Solution Overview
Problem
Display devices face challenges in supplying appropriate current to pixels with varying light emission efficiencies, leading to inconsistent luminance and unnecessary power consumption due to process variations during manufacturing.
Innovation Solution
A display device and driving method that include a current sensor to generate sensing current values, a memory to store block target current values, and a scale factor generator to adjust grayscale values based on the difference between sensed and target current values, ensuring optimal current supply to pixels across different light emission efficiencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed current is supplied to all pixels, then the device complexity is reduced, but luminance uniformity deteriorates due to process variations in light emission efficiency
Solution Approach 1:
The patent divides pixels into multiple blocks and measures the light emission efficiency of each block separately. Different current values are then applied to different blocks based on their measured efficiencies, allowing each local region to receive optimized current rather than a uniform current across the entire display.
Solution Approach 2:
The patent dynamically adjusts the current supplied to each block based on measured light emission efficiency. The system measures efficiency during initialization and continuously monitors during operation, adjusting current values in real-time to compensate for variations and maintain luminance uniformity.
2Illumination intensity
If current is increased to compensate for low light emission efficiency, then luminance is improved, but power consumption increases
Solution Approach 1:
The patent changes the current parameter dynamically based on measured light emission efficiency. By adjusting current values to match actual pixel performance characteristics, the system achieves target luminance levels without applying excessive current, thereby optimizing power consumption while maintaining required brightness levels.
3Stability of the object's composition
If block target current values are measured and stored for multiple blocks, then luminance uniformity is improved, but device complexity increases
Solution Approach 1:
The patent segments the pixel array into multiple blocks and measures light emission efficiency for each block separately. This segmentation allows the system to manage complexity by handling smaller groups of pixels independently, storing separate current values for each block rather than attempting to manage all pixels uniformly.
Solution Approach 2:
The patent performs preliminary measurement of light emission efficiency for each block during initialization and stores the measured values as block target current values. This preliminary action allows the system to pre-calculate and store optimized current values, avoiding the need for complex real-time calculations during operation.
4Stability of the object's composition
If grayscale values are scaled using block target current values, then luminance consistency is improved, but processing complexity increases
Solution Approach 1:
The patent implements feedback by measuring the actual light emission efficiency of each block and using these measurements to scale grayscale values. The measured block target current values feed back into the grayscale scaling process, creating a closed-loop system that automatically compensates for variations in light emission efficiency.
Data Source
AI summary
A display device and a driving method thereof are disclosed, and the display device includes a first pixel connected to a first data line, a first scan line, and a first power source line, emitting light in a first period, and not emitting light in a second period following the first period; a second pixel connected to a second data line, the first scan line, and the first power source line, not emitting light in the first period, and emitting light in the second period; a current sensor sensing a current flowing through the first power source line in the first period to provide a first sensing current value, and sensing the current flowing through the first power source line in the second period to provide a second sensing current value; and a memory storing a first block target current value corresponding to the first sensing current value and a second block target current value corresponding to the second sensing current value.