Light Emitting Module With Varying LED Chip Areas

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Solution Overview

Problem

Existing light emitting modules for liquid crystal display (LCD) backlight assemblies face inefficiencies due to varying light-electrical efficiencies of red, green, and blue LEDs, leading to insufficient light intensity and mismatched light emitting areas, which affect the overall light emitting efficiency and reproducibility of white light.

Innovation Solution

A light emitting module with point light sources featuring first, second, and third light emitting chips with different light emitting areas, where at least one chip has a larger area than the others, optimized to achieve a specific ratio of light intensities to enhance white light emission, with the blue light emitting chip typically having the largest area to ensure sufficient light intensity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If red, green and blue LEDs with the same light emitting area are used, then the device structure is simple, but the light intensity of at least one color is insufficient to emit white light

Engineering Contradiction:
Improvestructure simplicityVSAvoidlight intensity
Core Design Contradiction:
Device complexityVSIllumination intensity

Solution Approach 1:

The patent applies local quality by making the light emitting areas of red, green and blue LEDs different from each other. Specifically, the blue LED has a larger light emitting area than the red and green LEDs, compensating for the lower light-electrical efficiency of blue LEDs and ensuring sufficient blue light intensity for white light emission.

Inventive Principle:
Principle #3Local quality

2Illumination intensity

If the light emitting area of blue LED is increased to compensate for low light-electrical efficiency, then the light intensity of blue light is sufficient, but the light emitting area becomes larger than required

Engineering Contradiction:
Improveblue light intensityVSAvoidlight emitting efficiency
Core Design Contradiction:
Illumination intensityVSLoss of energy

Solution Approach 1:

The patent changes the parameter of light emitting area for each LED color differently. The blue LED is given a larger light emitting area to compensate for its lower light-electrical efficiency, while red and green LEDs have smaller light emitting areas matching their higher efficiency, optimizing overall light emitting efficiency.

Inventive Principle:
Principle #35Parameter changes

3Use of energy by moving object

If the wavelength of blue light is reduced to about 450 nm or lower, then the light-electrical efficiency is enhanced, but the light intensity of blue light becomes insufficient

Engineering Contradiction:
Improvelight-electrical efficiencyVSAvoidblue light intensity
Core Design Contradiction:
Use of energy by moving objectVSIllumination intensity

Solution Approach 1:

The patent addresses this contradiction by making the blue LED's light emitting area larger than those of red and green LEDs. This local differentiation compensates for the reduced light intensity caused by using shorter wavelength blue light (450 nm or lower), ensuring sufficient blue light contribution to white light emission.

Inventive Principle:
Principle #3Local quality

4Illumination intensity

If two green LEDs are used in R, G, G, B array to increase green light intensity, then the green light intensity is sufficient, but the device complexity increases

Engineering Contradiction:
Improvegreen light intensityVSAvoidarray complexity
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

Instead of adding more green LEDs, the patent uses local quality by giving the blue LED a larger light emitting area and red and green LEDs smaller light emitting areas. This approach achieves the required green light intensity through optimized area distribution rather than increasing the number of components.

Inventive Principle:
Principle #3Local quality

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 configuration increases the light intensity of the light emitting module, eliminates unused light emitting area, and enhances the light emitting efficiency by ensuring that at least one chip provides sufficient light intensity to produce white light, thereby improving the light reproducibility and efficiency of the backlight module.

Implementation Method 1

a first light emitting chip emitting first light, a second light emitting chip emitting second light, and a third light emitting chip emitting third light

Methodology Applied
Scientific EffectLight-emitting diode: Light Emitting Diode

Data Source

PatentEP1919262B1Light emitting module and display device having the same
Publication Date: 2012.04.11 SAMSUNG DISPLAY CO LTD
  • EP1919262B1 patent drawingFigure 1~2
  • EP1919262B1 patent drawingFigure 3~4
  • EP1919262B1 patent drawingFigure 5~6

AI summary

A light emitting module includes a plurality of point light sources and a substrate applying driving power. Each of the point light sources includes a first light emitting chip emitting first light, a second light emitting chip emitting second light, and a third light emitting chip emitting third,light, At least one restriction light emitting chip among the first, second and third light emitting chips has a larger light emitting area than that of a remainder of the light emitting chips, so that a light emitting intensity enough to display white light by mixing the first, second and third light is obtained.