Quantum Dot Display Device Light Focusing Layer

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Solution Overview

Problem

Display devices face challenges in minimizing energy loss and achieving high photo-efficiency and color purity due to light absorption by color filters, leading to deteriorated luminance and color reproducibility, especially when scaling up production.

Innovation Solution

A display device design incorporating a quantum dot-based color filter layer that converts light, combined with a light-focusing layer and an optical filter to optimize light path and reduce absorption, utilizing specific materials like silver, aluminum, and indium tin oxide for electrodes, and including a light-focusing layer with convex lenses or micro-prisms to enhance light recycling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a color filter is used to produce display colors, then the display device can be produced on a larger scale, but light is absorbed by the color filter causing energy loss and deteriorated luminance and color purity

Engineering Contradiction:
Improveproduction scaleVSAvoidenergy loss
Core Design Contradiction:
ProductivityVSLoss of energy

Solution Approach 1:

The patent introduces a light-focusing layer as an intermediary component between the light source and color filter. This layer focuses emitted light onto the color filter, increasing the proportion of light that effectively passes through while reducing absorption losses. The light-focusing layer acts as a mediator that optimizes the interaction between light and the color filter, thereby reducing energy loss while maintaining large-scale production capabilities

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent modifies the optical parameters of the system by introducing a light-focusing layer with specific refractive index properties and optical path designs. This changes how light propagates through the display device, increasing the effective transmittance through the color filter and reducing the energy loss associated with light absorption, while preserving the scalability benefits of using color filters

Inventive Principle:
Principle #35Parameter changes

2Productivity

If a color filter is used to produce display colors, then the display device can be produced on a larger scale, but color purity is deteriorated since the final emitted light may have a wide full width at half maximum

Engineering Contradiction:
Improveproduction scaleVSAvoidcolor purity
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The light-focusing layer serves as an optical intermediary that concentrates light onto the color filter in a controlled manner. This focused illumination improves the efficiency of color separation and reduces the mixing of adjacent color wavelengths, thereby narrowing the FWHM and improving color purity while maintaining the manufacturing scalability of color filter-based displays

Inventive Principle:
Principle #24Intermediary (Mediator)

3Manufacturing precision

If pixels individually emitting light are used, then high color purity and excellent image quality can be achieved, but each pixel may be formed with different materials making it difficult to produce on a large scale

Engineering Contradiction:
Improvecolor purityVSAvoidproduction scale
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent merges the advantages of both approaches by combining a light source layer (which can be uniformly manufactured) with a color filter layer. The light-focusing layer enhances this hybrid approach by ensuring efficient light transfer, achieving color purity comparable to individual pixel emission while maintaining the manufacturing scalability of uniform layer structures

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The light-focusing layer provides a universal solution that works across the entire display panel regardless of the specific pixel configuration. It enables the color filter-based display to achieve performance levels previously only attainable with complex individual pixel structures, making the simpler, more scalable color filter approach universally effective across the display

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

The solution minimizes energy loss, improves photo-efficiency, and maintains high color purity and reproducibility even at wide viewing angles, while allowing for larger-scale production by effectively recycling light and reducing unwanted absorption.

Implementation Method 1

The color filter layer may further include a quantum dot configured to convert the first light into a second light, and a second quantum dot configured to convert the first light into a third light different from the second light

Methodology Applied
Scientific EffectPhotoluminescence: Photoluminescence

Implementation Method 2

a light-focusing layer configured to focus the first light emitted from the organic light emitting layer into the color filter layer

Methodology Applied
Scientific EffectOptical focusing: Focusing

Implementation Method 3

The color filter layer may further include a light scattering material

Methodology Applied
Scientific EffectLight scattering: Scattering

Data Source

PatentEP3648171B1Display device
Publication Date: 2022.10.12 SAMSUNG ELECTRONICS CO LTD
  • EP3648171B1 patent drawingFigure 1
  • EP3648171B1 patent drawingFigure 2
  • EP3648171B1 patent drawingFigure 3

AI summary

A display device including a light source including a first electrode (112) having a light reflectance for a first light of greater than or equal to about 60 %; an organic light emitting layer (120a) disposed on the first electrode and emitting the first light; and a second electrode (114) disposed on the organic light emitting layer and having a light transmittance in a visible wavelength region of greater than or equal to about 70 %, wherein the light source has a first absorption peak in a wavelength region of about 650 nanometers (nm) to about 750 nm or a second absorption peak in a wavelength region of about 550 nm to about 600 nm at a viewing angle of about 55 degrees to about 85 degrees, and a color filter layer (130r, 130g, 130b) disposed above the light source and including a quantum dot configured to convert the first light into a second light.