Display Panel Brightness Uniformity Control

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Solution Overview

Problem

Conventional display panels face challenges in achieving uniform backlight brightness due to variations in light emitting devices, leading to inadequate brightness control and quality issues, particularly under different ambient light conditions, which results in time and cost inefficiencies during production and potential image degradation.

Innovation Solution

A display panel with a two-dimensional array of light-emitting panel elements, equipped with uniformly arranged pixel brightness sensors and incident light sensors, which determine and adjust brightness differences to compensate for inhomogeneities, ensuring uniform brightness and luminance across the panel.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If equivalent light emitting devices are used in production, then manufacturing process is simplified, but brightness uniformity deteriorates due to component tolerances

Engineering Contradiction:
Improvemanufacturing process simplicityVSAvoidbrightness uniformity
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The invention divides the uniformity correction task into individual pixel-level operations. Each pixel is equipped with its own luminance sensor that independently measures and corrects its brightness, rather than relying on uniformity of all light emitting devices. This segmentation allows each pixel to be adjusted individually, achieving uniformity despite variations in equivalent devices.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention implements feedback control at the pixel level. Luminance sensors in each pixel continuously measure the actual light output and feed this information back to the control circuit, which then adjusts the drive signal to maintain uniform brightness. This closed-loop feedback system compensates for variations in equivalent light emitting devices during operation.

Inventive Principle:
Principle #23Feedback

2Manufacturing precision

If brightness testing and calibration is performed on every light emitting device, then brightness uniformity is improved, but production time and cost increase

Engineering Contradiction:
Improvebrightness uniformityVSAvoidproduction efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The invention performs brightness uniformity correction as a preliminary action during the display panel manufacturing process, before the product is shipped to customers. By integrating luminance sensors and implementing automatic correction during production, the need for time-consuming manual testing and calibration of each light emitting device is eliminated, improving production efficiency while maintaining uniformity.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention enables the display panel to perform its own brightness uniformity correction automatically during production. Each pixel's luminance sensor independently measures and corrects its own brightness without requiring external testing equipment or manual calibration, thereby streamlining the manufacturing process and improving productivity.

Inventive Principle:
Principle #25Self-service

3Adaptability or versatility

If luminance sensors are placed on the display panel to detect ambient light effects, then perceived brightness control is improved, but device complexity increases

Engineering Contradiction:
Improveambient light adaptationVSAvoidsensor integration complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The invention makes the luminance sensors serve multiple functions: they measure both the backlight luminance for uniformity correction and the ambient light effects on perceived brightness. This multi-functionality allows the same sensor infrastructure to address both backlight uniformity and ambient light adaptation, reducing overall system complexity despite the added adaptability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The invention merges the backlight uniformity correction function and the ambient light compensation function into a single integrated system. Both functions utilize the same luminance sensor data and are controlled by the same control circuit, combining what could be separate systems into one unified solution, thereby managing device complexity while achieving both adaptability goals.

Inventive Principle:
Principle #5Merging (Combining)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This solution enables dynamic brightness control, achieving 100% brightness uniformity and improved performance under all environmental conditions, reducing the need for manual calibration and enhancing the quality and reliability of display panels.

Implementation Method 1

a first subset of pixel brightness sensors uniformly arranged in both dimensions of the panel at panel elements of the panel, for sensing brightness of the light emitted from the panel elements

Methodology Applied
Scientific EffectPhotoelectric Effect: Photoelectric Effect

Implementation Method 2

a second subset of incident light sensors uniformly arranged in both dimensions of the panel at panel elements of the panel, for sensing luminance of ambient light incident on the panel elements

Methodology Applied
Scientific EffectPhotoelectric Effect: Photoelectric Effect

Implementation Method 3

a plurality of panel elements arranged in a two dimensional array and being capable of emitting light

Methodology Applied
Scientific EffectLight Emitting Diode: Light Emitting Diode

Data Source

PatentEP2028640B1Auto adjusting backlight and pixel brightness on display panels
Publication Date: 2013.04.24 VESTEL ELEKTRONIK SANAYI & TICARET ANONIM SIRKETI
  • EP2028640B1 patent drawingFigure 1
  • EP2028640B1 patent drawingFigure 2
  • EP2028640B1 patent drawingFigure 3

AI summary

A display panel (1) is disclosed, comprising a plurality of panel elements (2) arranged in a two dimensional array and being capable of emitting light. A first subset of pixel brightness sensors (8) are uniformly arranged in both dimensions of the panel at panel elements of the panel, for sensing brightness of the light emitted from the panel elements at which they are arranged. A brightness determining means (25), connected to the pixel brightness sensors, determines brightness differences of the panel elements at which the pixel brightness sensors (8) are arranged, and compensation means (26) adjust the brightness of panel elements (2) of the display panel (1) based on the determined brightness differences, in order to compensate brightness inhomogeneities among the panel elements (2). Additionally or alternatively, incident light sensors (9) uniformly arranged at panel elements (2) of the panel (1), sense illuminance of ambient light incident on the panel elements (2).