Display Device Brightness Correction Memory Read Rate

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Solution Overview

Problem

Existing display devices face challenges in correcting brightness irregularities due to variations in threshold voltage (Vth) and slope (µ) of TFTs, leading to inconsistencies in brightness across pixels, especially in high-resolution displays where the data rate for correction data exceeds the capabilities of standard memory read rates, causing inefficiencies and increased power consumption.

Innovation Solution

The solution involves dividing the display region into small regions of n unit pixels, storing average correction values and derived correction values in memory, and performing correction calculations only every m frames, reducing the frequency of memory read operations and using a double buffer system to alternate data reading from flash memory at lower frequencies, thereby reducing power consumption and radiation issues.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If correction data is read for every frame at high resolution, then brightness uniformity is improved, but power consumption increases and memory read rate requirements exceed standard capabilities

Engineering Contradiction:
Improvebrightness uniformityVSAvoidpower consumption
Core Design Contradiction:
Illumination intensityVSUse of energy by moving object

Solution Approach 1:

The patent applies periodic action by updating correction data only at specific intervals (every n frames) rather than every frame. The correction data is updated periodically based on a predetermined period, reducing the frequency of memory read operations while maintaining acceptable brightness uniformity through accumulated correction values that compensate for TFT variations over time.

Inventive Principle:
Principle #19Periodic action

2Illumination intensity

If correction data is read for every frame, then brightness inconsistency correction is improved, but memory read rate requirements exceed standard memory capabilities

Engineering Contradiction:
Improvebrightness inconsistency correctionVSAvoidmemory read rate
Core Design Contradiction:
Illumination intensityVSSpeed

Solution Approach 1:

The system reduces memory read rate requirements by implementing periodic updates of correction data every n frames instead of every frame. This periodic action lowers the data read frequency to match standard memory capabilities while maintaining correction effectiveness through accumulation of correction values over the periodic interval.

Inventive Principle:
Principle #19Periodic action

3Illumination intensity

If correction calculations are performed every frame, then brightness uniformity is improved, but processing time and computational load increase

Engineering Contradiction:
Improvebrightness uniformityVSAvoidprocessing time
Core Design Contradiction:
Illumination intensityVSLoss of time

Solution Approach 1:

The patent reduces processing time by performing correction calculations periodically every n frames rather than every frame. The periodic execution of correction calculations decreases computational load and processing time while maintaining brightness uniformity through the accumulation mechanism that continues to apply corrections based on previously calculated values.

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP2422339B1Display device
Publication Date: 2018.04.11 GLOBAL OLED TECHNOLOGY LLC
  • EP2422339B1 patent drawingFigure 1
  • EP2422339B1 patent drawingFigure 2
  • EP2422339B1 patent drawingFigure 3

AI summary

The rate of reading from a memory for storing display irregularity correction data is lowered. At the time of display, calculation is carried out in a correction calculation section 12 using an input signal and correction data in RAM 22, and brightness inconsistency correction is carried out. The way in which correction calculation is carried out in the correction calculation section 12 is changed for every frame.