Wavelength Converter Absorbing 550-650nm for Display Color

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Solution Overview

Problem

Existing display devices, particularly liquid crystal display devices, face challenges in improving display quality due to the need for separate light sources and the use of non-emissive elements, which can result in reduced color reproduction and potential health risks from harmful excitation light emitting bodies like quantum dots containing Cd.

Innovation Solution

A display device incorporating a backlight with a light guide plate and a light absorbing sheet that includes excitation light emitting bodies and absorbers to absorb specific wavelengths, enhancing color reproduction by filtering out wavelengths between 550 nm to 650 nm, thereby improving display quality and safety by excluding harmful materials.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If quantum dots containing Cd are used as excitation light emitting bodies, then color reproduction is improved, but health risks and safety issues arise

Engineering Contradiction:
Improvecolor reproductionVSAvoidhealth risks from Cd
Core Design Contradiction:
Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

The patent extracts and removes the harmful Cd-containing quantum dots from the system while retaining the desired color conversion function through alternative materials that do not contain cadmium

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent converts the harmful effect of broad-spectrum excitation light into a beneficial selective wavelength conversion process, where the excitation light is used to activate safe alternative phosphors that convert specific wavelengths to achieve excellent color reproduction without Cd toxicity

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

2Illumination intensity

If a light absorbing sheet is added to filter specific wavelengths, then display quality is improved, but device complexity increases

Engineering Contradiction:
Improvedisplay qualityVSAvoidstructure complexity
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The patent merges the light absorbing function with the existing light guide plate or diffusion plate by integrating the light absorbing sheet into the optical path, thereby improving display quality without adding significant structural complexity

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The light absorbing sheet acts as an intermediary element between the light source and the display panel, selectively absorbing specific wavelengths (550-650 nm) to enhance color accuracy while maintaining a relatively simple overall structure

Inventive Principle:
Principle #24Intermediary (Mediator)

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 enhances display quality by improving color reproduction and safety by filtering out wavelengths that degrade display quality and eliminating harmful materials, resulting in a more efficient and safer display device.

Implementation Method 1

The light guide plate includes a plurality of excitation light emitting bodies to be excited by receiving the first light, and thereby emit a second light. The first light may be a blue light. The second light may include a red light and a green light.

Methodology Applied
Scientific EffectPhotoluminescence: Photoluminescence

Implementation Method 2

The absorbers receive the second light from the light guide plate and absorb a portion of the second light having a wavelength of about 550 nm to about 650 nm.

Methodology Applied
Scientific EffectSelective absorption: Absorption (EM radiation)

Data Source

PatentEP3260910B1Display device having wavelength converter
Publication Date: 2024.07.24 SAMSUNG DISPLAY CO LTD
  • EP3260910B1 patent drawingFigure 1
  • EP3260910B1 patent drawingFigure 2A
  • EP3260910B1 patent drawingFigure 2B

AI summary

A display device is disclosed, the display device includes a backlight and a display panel on the backlight. The backlight includes a light source to provide a first light, and an optical wavelength converter (OU) to receive the first light and emits a second light. The optical wavelength converter (OU) includes a light emitting part having a plurality of excitation light emitting bodies (LUB) to be excited by receiving the first light, and thereby emit the second light, and a light absorbing part (ASP) including a plurality of absorbers (ABS) provided on the light emitting part to receive the second light and absorb a portion of the second light having a wavelength of about 550 nm to about 650 nm.