Display Device Variable Sensing Periods for Flicker Reduction

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Solution Overview

Problem

Conventional electroluminescent display devices experience compensation cycle delay and image defects when frame frequency varies, leading to visible flicker and luminance fluctuations due to compensation delay and external compensation scheme inefficiencies.

Innovation Solution

A display device with a timing controller and sensing circuit that adjusts the length of the vertical blank period and increases the number of sensing periods proportionally, ensuring consistent compensation command signal intervals and minimizing cognitive errors through multi-sensing during variable frame frequencies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If frame frequency is varied depending on input image to improve adaptability, then adaptability is improved, but compensation cycle delay and image defects occur due to fixed sensing periods

Engineering Contradiction:

Improveframe frequency adaptabilityVSAvoidcompensation accuracy

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies dynamics by making the number of sensing periods variable rather than fixed. The timing controller dynamically adjusts the number of sensing periods based on the detected frame frequency, ensuring that compensation sensing adapts to different frame rates. This resolves the contradiction by allowing the system to maintain reliable compensation accuracy while adapting to varying frame frequencies.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of sensing period count based on frame frequency. When frame frequency changes, the timing controller modifies the number of sensing periods accordingly. This parameter adjustment ensures that compensation sensing remains synchronized with the variable frame rate, maintaining both adaptability and compensation reliability.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If number of sensing periods is increased to improve compensation accuracy, then compensation accuracy is improved, but vertical blank period time is extended

Engineering Contradiction:

Improvecompensation accuracyVSAvoidvertical blank period duration

Core Design Contradiction:

ReliabilityVSDuration of action of moving object

Solution Approach 1:

The patent uses dynamics by making the number of sensing periods variable. Instead of always using the maximum number of sensing periods, the system adjusts the count based on the actual frame frequency detected. This allows the vertical blank period to be extended only when necessary for accurate compensation at lower frame rates, while maintaining shorter periods at higher frame rates.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of sensing period count dynamically. The timing controller detects frame frequency and adjusts the number of sensing periods accordingly, optimizing the balance between compensation accuracy and vertical blank period duration. This parameter adjustment ensures accurate compensation without unnecessarily extending the vertical blank period.

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If fixed sensing periods are used to simplify control, then device complexity is reduced, but compensation cycle delay occurs when frame frequency changes abruptly

Engineering Contradiction:

Improvecontrol simplicityVSAvoidcompensation cycle delay

Core Design Contradiction:

Device complexityVSLoss of time

Solution Approach 1:

The patent applies feedback by having the timing controller detect the actual frame frequency and use this information to adjust the number of sensing periods. This feedback mechanism ensures that the sensing periods are optimized for the current frame rate, preventing compensation cycle delay while maintaining relatively simple control logic through automatic adaptation.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent makes the sensing period configuration dynamic rather than static. The timing controller adjusts the number of sensing periods based on detected frame frequency, allowing the system to adapt to abrupt frame rate changes without fixed, potentially mismatched sensing periods. This dynamic adjustment reduces compensation cycle delay while keeping control manageable.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS11875725B2Display device and method of driving the same

Publication Date: 2024.01.16 LG DISPLAY CO LTD

AI summary

A display device including a display panel according to an embodiment of the present application includes a plurality of pixels, a timing controller configured to receive a compensation command signal in a vertical blank period in which no image data are written in the pixels, and a sensing circuit configured to sense driving properties of the pixels in at least one sensing period corresponding to the compensation command signal, wherein a length of the vertical blank period is different from each other in a first frame and a second frame, and a number of sensing periods having a predetermined length varies depending on the length of the vertical blank period.