LED Lens Slanted Surface for Backlight Color Spot Elimination

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Solution Overview

Problem

Existing LCD display devices using side emission type LEDs suffer from color spots due to light emitted directly upward, which reduces light efficiency and requires a light guide plate that can absorb or reflect light, increasing power consumption and reducing reliability.

Innovation Solution

The use of an LED with a lens portion having a slanted upper surface at an angle of 55 to 85 degrees, which reflects light traveling directly upward, eliminating the need for a light guide plate and enhancing light mixing, thereby preventing color spots and improving efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a light guide plate is used to reflect or absorb light in related art LCD modules, then color spots are prevented, but light efficiency is reduced and power consumption increases

Engineering Contradiction:
Improvecolor spot preventionVSAvoidlight efficiency
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent removes the light guide plate from the backlight assembly by designing an LED lens with a specific slanted upper surface that directly reflects upward light sideways, eliminating the need for the separate light guide plate component and its associated light loss

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The LED lens structure performs multiple functions itself: it refracts light through its side surface and reflects upward light sideways through its slanted upper surface, making the LED assembly self-sufficient without requiring additional light guide plates or reflectors

Inventive Principle:
Principle #25Self-service

2Reliability

If a light guide plate is used to mix light in related art LCD modules, then color spots are prevented, but device complexity increases

Engineering Contradiction:
Improvecolor spot preventionVSAvoidbacklight assembly structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the light refraction function and light reflection function into a single integrated LED lens structure, merging multiple optical functions that were previously performed by separate components (LED, light guide plate, reflectors) into one unified element

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The LED lens with slanted upper surface performs multiple functions simultaneously: it refracts light through its side surface to control emission angle and reflects upward light sideways through its slanted upper surface, making it a multi-functional component that replaces several separate parts

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

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 effectively prevents color spots and increases light efficiency by ensuring that light is distributed within a wider angle range, reducing power consumption and enhancing the reliability of the backlight assembly.

Implementation Method 1

a lens portion covering the emitting portion, contacting the emitting portion, refracting light emitted from the emitting portion

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 2

the slanted upper surface has a reversed cone shape... reflects light traveling directly upward

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP1737051B1Backlight assembly including light emitting diode and display device including the same
Publication Date: 2018.01.17 LG DISPLAY CO LTD
  • EP1737051B1 patent drawingFigure 1
  • EP1737051B1 patent drawingFigure 2
  • EP1737051B1 patent drawingFigure 3

AI summary

A light emitting diode is provided which includes an emitting portion (104) on a base portion (102) and a lens portion (106) covering the emitting portion and having a slanted upper surface (106a). The slanted upper surface has a reversed cone shape and has a slanted angle (θ) of about 55 to 85 degrees with respect to a center axis of the emitting portion.