Display Pixel Compensation Using Moving Average Grouping

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Solution Overview

Problem

Active matrix display devices face challenges in maintaining consistent pixel performance due to variations in transistor characteristics over time and manufacturing differences, leading to inconsistent current output and convergence issues across the panel, especially when temperature and ambient light change rapidly.

Innovation Solution

A method is introduced to divide pixels into groups, using moving averages and initial values to set converged parameters for each group, allowing for faster convergence through dynamic gear shifting and Least Mean Square adaptation, enabling quicker compensation for transistor changes and ambient conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If individual pixel compensation is performed for each pixel in the display device, then pixel uniformity and accuracy are improved, but the compensation time and processing complexity increase significantly

Engineering Contradiction:
Improvepixel output accuracyVSAvoidcompensation time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent divides the display panel pixels into multiple groups (e.g., first group and second group) and performs compensation processing on each group separately rather than individually on all pixels. This segmentation reduces the computational burden and time required while maintaining pixel output accuracy through group-level convergence determination.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent performs compensation processing on only a portion of the pixels (one group) at a time, using the converged parameters from the first group to initialize the second group. This partial action approach reduces overall compensation time while still achieving uniform pixel output across the entire display panel.

Inventive Principle:
Principle #16Partial or excessive action

2Stability of the object's composition

If compensation processing is performed on all pixels simultaneously, then pixel uniformity is achieved, but the processing time becomes excessively long and may exceed convergence time

Engineering Contradiction:
Improvepixel uniformityVSAvoidcompensation speed
Core Design Contradiction:
Stability of the object's compositionVSProductivity

Solution Approach 1:

The patent performs preliminary compensation processing on the first group of pixels to determine converged parameters before using these parameters as initial values for the second group. This preliminary action on a subset of pixels accelerates the overall compensation process while maintaining pixel uniformity across the entire display.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses the converged parameters from the first pixel group as an intermediary to initialize the compensation process for the second pixel group. This intermediary approach transfers the compensation knowledge from the first group to the second group, reducing processing time while maintaining uniformity.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Illumination intensity

If high voltages are applied to transistor gates to control pixel output, then pixel brightness and color control are achieved, but transistor threshold voltage changes over time due to heat and aging

Engineering Contradiction:
Improvepixel brightnessVSAvoidtransistor characteristic stability
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The patent implements a feedback mechanism where pixel output currents are measured and used to determine convergence parameters that compensate for transistor threshold voltage changes. This feedback loop continuously adjusts compensation values to maintain reliable pixel output despite transistor aging and thermal effects.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent changes the compensation parameters (A and B values) based on measured pixel output currents and transistor performance degradation. By dynamically adjusting these parameters, the system compensates for transistor threshold voltage shifts while maintaining consistent pixel brightness and color output.

Inventive Principle:
Principle #35Parameter changes

4Manufacturing precision

If manufacturing variations are compensated for individually, then pixel consistency is improved, but the complexity and cost of the compensation system increase

Engineering Contradiction:
Improvepixel consistencyVSAvoidcompensation system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent merges the compensation processing for multiple pixels into group-level operations, where converged parameters are determined for groups rather than individual pixels. This merging reduces system complexity while maintaining pixel consistency through the use of moving averages and group convergence determination.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP4191572A1Display apparatus and driving method thereof
Publication Date: 2023.06.07 SAMSUNG DISPLAY CO LTD
  • EP4191572A1 patent drawingFigure 1
  • EP4191572A1 patent drawingFigure 2
  • EP4191572A1 patent drawingFigure 3A

AI summary

A method of compensating for change in pixel and a display device incorporating such method are presented. The method includes dividing pixels into groups including a previous group L-1, a current group L and a next group L+1; determining a first converged value Aconverged[L] and a second converged value Bconverged[L] for each pixel in the current group L starting with a first initial value Ao[L] and a second initial value Bo[L]; for each pixel in the current group L, determining a first moving average Amean[L] and a second moving average Bmean[L] as follows: AmeanL=AmeanL−1K−1+ALK, BmeanL=BmeanL−1K−1+BLK, wherein Amean[L-1] is a first moving average of a pixel in the corresponding column in the previous group L-1, Bmean[L-1] is a second moving average of a pixel in the corresponding column in the previous group L-1, and K is a moving average window; and for the next group L+1, setting a first initial value A0[L+1] and a second initial value B0[L+1] of each pixel to Amean[L] and Bmean[L].