Display Device Pixel Compensation Using Dummy Reference Signals
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Solution Overview
Problem
Existing display devices face deviations in channel specifications during pixel compensation due to manufacturing process variations, leading to inaccurate compensation and defects like vertical lines on the screen.
Innovation Solution
A display device with a data driver including buffer amplifiers and a sensor that applies a first and second sensing voltage during different periods, generating compensation data based on the difference between the sensing signals received, using a global amplifier to reduce channel deviations by applying the same sensing voltage across all pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If buffer amplifiers are used to supply sensing voltage to each data line, then pixel compensation can be performed, but channel deviation occurs due to manufacturing process variations
Solution Approach 1:
A dummy pixel is introduced as an intermediary element that receives the same sensing voltage through a dummy buffer amplifier. This dummy pixel serves as a reference to measure and compensate for the channel deviations caused by manufacturing variations in the actual buffer amplifiers, enabling accurate pixel compensation despite channel inconsistencies
Solution Approach 2:
The patent changes the measurement approach by introducing a dummy pixel with identical structure to the actual pixels. By measuring the sensing signal from the dummy pixel and comparing it with the actual pixel signals, the system can calculate compensation values that correct for channel deviations. This parameter change transforms the problem from direct measurement to comparative measurement
2Productivity
If multiple buffer amplifiers are connected to data lines, then sensing can be performed for each pixel, but deviation between channels occurs during sensing
Solution Approach 1:
The patent segments the sensing process into two independent parts: measurement of actual pixel sensing signals and measurement of dummy pixel sensing signals. By separating these measurements and using the dummy pixel as a reference, the system can compensate for manufacturing variations while maintaining the ability to sense all pixels through multiple buffer amplifiers
Solution Approach 2:
A dummy pixel is created as a copy of the actual pixels with identical structure and connection to buffer amplifiers. This copy is used specifically for measuring channel characteristics. By copying the pixel structure, the dummy pixel experiences the same manufacturing variations as actual pixels, allowing the system to measure and compensate for channel deviations
3Reliability
If buffer amplifiers with different gains are used due to process deviation, then pixel compensation can be attempted, but vertical line defects occur on the screen
Solution Approach 1:
The patent implements feedback by measuring the sensing signal from the dummy pixel and using this information to calculate compensation values. These compensation values are then fed back to correct the sensing signals from actual pixels. This feedback loop continuously adjusts the compensation based on measured channel deviations, preventing vertical line defects
Solution Approach 2:
The patent converts the harmful effect of manufacturing process deviations into a beneficial measurement opportunity. By intentionally creating a dummy pixel that experiences the same deviations, the system can measure the deviation magnitude and use it to correct actual pixel compensation. The harm of variation becomes the basis for accurate compensation
Data Source
AI summary
A display device includes a display panel including a plurality of pixels connected to data lines and sensing lines, a data driver including a plurality of buffer amplifiers which supplies a first sensing voltage to the data lines during a first sensing period and a sensor which receives a first sensing signal from the pixels through the sensing lines during the first sensing period, and a global amplifier which supplies a second sensing voltage to the data lines during a second sensing period different from the first sensing period. The sensor receives a second sensing signal corresponding to the second sensing voltage from the pixels through the sensing lines during the second sensing period, and generates compensation data based on a difference value between the first sensing signal and the second sensing signal.