Display Device Brightness Control Using APL Reference Frames

Solution Overview

Problem

Existing display devices struggle with afterimages and excessive brightness reduction in dark-gradation images, leading to user discomfort.

Innovation Solution

A display device employing an improved brightness reduction algorithm that calculates Average Picture Level (APL) values to determine whether to apply brightness reduction, updating reference frames based on APL differences, and adjusting brightness accordingly to differentiate between still and moving images.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If brightness reduction algorithm is applied to prevent afterimages, then afterimages are reduced, but brightness is excessively reduced in dark-gradation moving images causing user discomfort

Engineering Contradiction:

ImproveafterimagesVSAvoidbrightness

Core Design Contradiction:

Object-affected harmful factorsVSIllumination intensity

Solution Approach 1:

The reference frame is dynamically updated based on APL value differences. When the APL difference between current and reference frames exceeds a threshold, the reference frame is updated to the current frame, allowing the system to adapt to changing image content and prevent excessive brightness reduction in moving images while maintaining afterimage prevention for still images

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes the APL threshold parameter to differentiate between still and moving images. By comparing APL values and updating the reference frame when thresholds are exceeded, the system adjusts its brightness reduction behavior based on image type, applying prevention for still images while avoiding excessive reduction in moving images

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If APL value comparison is used to determine still images, then still images are accurately identified, but dark-gradation moving images are misidentified as still images

Engineering Contradiction:

Improvestill image detection accuracyVSAvoidmoving image classification reliability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The reference frame is dynamically updated based on APL value differences. When the APL difference between current and reference frames exceeds a threshold, the reference frame is updated to the current frame, allowing the system to adapt to changing image content and prevent excessive brightness reduction in moving images while maintaining afterimage prevention for still images

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system uses feedback from APL value comparisons to continuously refine its classification. By comparing current frame APL with the reference frame and updating the reference when thresholds are exceeded, the system creates a feedback mechanism that improves classification reliability for both still and moving images across different gradation levels

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS20250316207A1Display device and method for operating same

Publication Date: 2025.10.09 LG ELECTRONICS INC

AI summary

A display device and a method of operating the same are disclosed. According to at least one of the various embodiments of the present disclosure, a display device includes a display outputting an input image; and a processor controlling the application of a brightness reduction algorithm to the input image, in which the processor, if calculating the difference in Average Picture Level (APL) values for determining whether to apply the brightness reduction algorithm, may determine whether to update the reference frame based on the difference between APL values of the current frame and the reference frame.