Semiconductor UV Light Emitting Device with Light Intensity Difference Reducing Layer

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Solution Overview

Problem

Semiconductor light emitting devices, such as LEDs, suffer from non-uniform brightness and color issues due to their small size, shape, and the use of wavelength converting materials, leading to inadequate light intensity and color uniformity, which hinders their adoption in display devices.

Innovation Solution

A semiconductor light emitting device is designed with a light intensity difference reducing layer between the ultraviolet semiconductor light emitting element and the wavelength converting material layer, using a transparent resin material to homogenize light and improve color rendering properties by incorporating phosphors that emit red, blue, and green light, ensuring uniform light emission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If multiple small-sized LEDs are arrayed on a substrate, then the light intensity can be increased, but non-uniform brightness occurs due to gaps between LEDs

Engineering Contradiction:
Improvelight intensityVSAvoidbrightness uniformity
Core Design Contradiction:
PowerVSIllumination intensity

Solution Approach 1:

The patent merges multiple small LED light sources into a unified illumination system by introducing a light-guiding plate that integrates and redistributes light from multiple LEDs across the entire display surface, eliminating gaps and achieving uniform brightness while maintaining high light intensity

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces a light-guiding plate as an intermediary component between the LEDs and the display surface. This mediator redistributes the light from multiple discrete LED sources to create uniform illumination across the entire display area, solving the non-uniform brightness problem

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If an LED chip is sealed with transparent resin, then the LED can be protected and used in various applications, but the small size of the LED chip limits its ability to provide complete line or surface light source

Engineering Contradiction:
ImproveLED protectionVSAvoidlight source coverage area
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The patent transitions from point-source LED chips to a planar light-guiding plate structure, utilizing the two-dimensional surface area to distribute light uniformly across the entire display region, thereby achieving complete surface light source coverage while maintaining protected LED chips

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 achieves improved light uniformity and color balance, resulting in a multicolor light emitting device with enhanced color rendering properties, suitable for various display applications requiring reduced size, weight, thickness, and power consumption, while maintaining high brightness for visibility in sunlight.

Implementation Method 1

a wavelength converting material layer, and a light intensity difference reducing layer provided between the ultraviolet semiconductor light emitting element and the wavelength converting material layer, wherein the wavelength converting material layer containing a wavelength converting material comprising at least one of three types of phosphors which, upon absorption of ultraviolet light emitted from the ultraviolet semiconductor light emitting element, emit red light, blue light, and green light, respectively

Methodology Applied
Scientific EffectPhotoluminescence: Photoluminescence

Implementation Method 2

a light intensity difference reducing layer provided between the ultraviolet semiconductor light emitting element and the wavelength converting material layer

Methodology Applied
Scientific EffectLight scattering: Scattering

Data Source

PatentEP4016650A1Semiconductor light emitting device and display device comprising the semiconductor light emitting device
Publication Date: 2022.06.22 SEOUL SEMICONDUCTOR
  • EP4016650A1 patent drawingFigure 1~3
  • EP4016650A1 patent drawingFigure 4A~5
  • EP4016650A1 patent drawingFigure 6

AI summary

The disclosure describes a semiconductor light emitting device (10) comprising a substrate (20); a plurality of semiconductor ultraviolet light emitting elements (30) provided on the substrate (20), wherein the semiconductor UV light emitting elements (30) are InGaN-based, GaN-based, or AIGaN-based diodes having peak wavelengths in a wavelength range of not less than 360nm and not more than 440nm; a continuous wavelength converting material layer (50); and a discontinuous layer of a light intensity difference reducing layer (40) covering any desired one or at least two of the semiconductor light emitting elements (30), wherein: the wavelength converting material layer (50) covers the discontinuous layer of the light intensity difference reducing layer (40), and the wavelength converting material layer (50) contains a wavelength converting material comprising at least three types of phosphors which, upon absorption of the light emitted from the semiconductor light emitting element, emit red light, blue light, and green light, respectively. Also disclosed are a backlight and a display device comprising the semiconductor light emitting device. The semiconductor light emitting device has improved uniformity of emitted light and reduced non-uniformity of brightness and chromaticity of emitted light. The disclosed semiconductor light emitting device is particularly suitable for use in various display devices, for example, in display devices in equipment where a reduction in size, a reduction in weight, a reduction in thickness, electric power saving, high brightness, and excellent color rendering properties are particularly required, for example, cellular phones, personal digital assistants, electronic dictionaries, digital cameras, computers, liquid crystal televisions (TVs), and peripheral devices of these devices.