Light Emitting Device Black Matrix Contrast Ratio

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Solution Overview

Problem

Outdoor electronic display devices using LEDs face challenges in achieving high contrast ratios due to light interference between different light emitting chips, which affects their brightness and visibility from a distance.

Innovation Solution

A light emitting device is designed with a support substrate featuring pads and a black matrix layer made of conductive carbon black material, covered by a transmissive resin layer, to reduce light interference and enhance contrast by absorbing external light and minimizing reflective indices around the light emitting chips.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a conventional LED structure without black matrix layer is used, then the device complexity is low, but the contrast ratio is poor due to light interference between chips

Engineering Contradiction:
Improvecontrast ratioVSAvoidstructure complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent divides the substrate into distinct functional zones: pads for electrical connection, black matrix regions for light absorption, and transparent resin regions for light transmission. This segmentation allows each region to perform its specific function optimally, preventing light interference between adjacent chips while maintaining clear boundaries for manufacturing

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The black matrix layer acts as an intermediary element between adjacent light emitting chips. It absorbs stray light and prevents optical crosstalk between chips, thereby improving contrast ratio without requiring changes to the LED chip structures themselves

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If light emitting chips are arranged closely to increase display density, then the productivity is improved, but light interference between chips increases reducing visibility

Engineering Contradiction:
Improvedisplay densityVSAvoidlight interference
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent extracts the light absorption function from the chip structure itself and places it in the black matrix layer on the substrate. This allows chips to be positioned closer together for higher density while the black matrix selectively removes harmful stray light without affecting the forward light emission from each chip

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The substrate is given different local properties: black matrix regions with high light absorption for areas between chips, and transparent resin regions with high light transmission for areas above chips. This local differentiation allows close chip spacing while maintaining visibility by treating different spatial zones with appropriate optical properties

Inventive Principle:
Principle #3Local quality

3Manufacturing precision

If a black matrix layer is added around light emitting chips to reduce light interference, then the contrast ratio is improved, but the manufacturing complexity increases

Engineering Contradiction:
Improvecontrast ratioVSAvoidmanufacturing process
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent combines the black matrix layer formation with the existing substrate manufacturing process. The black matrix is integrated into the substrate structure itself rather than being added as a separate post-processing step, allowing it to be manufactured simultaneously with the substrate and pad structures using standard PCB or flexible substrate fabrication techniques

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

The solution improves the contrast ratio and reliability of the light emitting device, providing higher visibility and reduced light interference, especially in outdoor electronic display devices.

Implementation Method 1

A light emitting device is designed with a support substrate featuring pads and a black matrix layer made of conductive carbon black material, covered by a transmissive resin layer, to reduce light interference and enhance contrast by absorbing external light

Methodology Applied
Scientific EffectLight absorption: Absorption (EM radiation)

Implementation Method 2

a transmissive resin layer provided on the support substrate to cover the pads, the black matrix layer, and the light emitting chips

Methodology Applied
Scientific EffectLight transmission: Refraction

Data Source

PatentEP3349258B1Light emitting device
Publication Date: 2021.01.06 SUZHOU LEKIN SEMICON CO LTD
  • EP3349258B1 patent drawingFigure 1
  • EP3349258B1 patent drawingFigure 2
  • EP3349258B1 patent drawingFigure 3~4

AI summary

A light emitting element disclosed in an embodiment comprises: a support substrate having a plurality of pads and a black matrix layer outside the plurality of pads; a plurality of light emitting chips, at least one of which is disposed on at least one of the plurality of pads; and a light-transmitting resin layer which is disposed on the support substrate and covers the pads, the black matrix layer, and the light emitting chips.