Direct Type Backlight QD Layer Thickness Reduction

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Solution Overview

Problem

Direct type backlights face limitations in flexibility due to the required distance between light emitting units and the light guide plate, which restricts the ability to adjust the backlight structure and increases thickness.

Innovation Solution

Incorporating a Quantum Dot (QD) layer on the light guide plate, where QD blocks are arranged in cavities and overlapped with light emitting units, allowing light to be uniformly scattered without the need for a specific distance between the units and the plate, and using reflectors and optical film layers to enhance light uniformity and efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If a certain distance is maintained between light emitting units and the light guide plate to ensure light uniformity, then the optical quality is improved, but the backlight structure flexibility is reduced and thickness increases

Engineering Contradiction:
Improvelight uniformityVSAvoidbacklight structure flexibility
Core Design Contradiction:
Illumination intensityVSAdaptability or versatility

Solution Approach 1:

A wavelength conversion member is introduced as an intermediary component between the light emitting units and the light guide plate. This member includes multiple wavelength conversion layers that convert light from different wavelengths, enabling light uniformity to be achieved without requiring a specific distance between the light emitting units and the light guide plate, thus resolving the contradiction between optical quality and structural flexibility

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The wavelength conversion member is constructed as a composite structure with multiple wavelength conversion layers, each layer containing different wavelength conversion particles. This composite material approach allows for optimized light conversion efficiency and uniformity while maintaining a compact structure that does not require additional spacing

Inventive Principle:
Principle #40Composite materials

2Illumination intensity

If a certain distance is maintained between light emitting units and the light guide plate to ensure light uniformity, then the optical quality is improved, but the overall thickness of the backlight increases

Engineering Contradiction:
Improvelight uniformityVSAvoidbacklight thickness
Core Design Contradiction:
Illumination intensityVSLength of stationary object

Solution Approach 1:

The wavelength conversion member serves as a compact intermediary that achieves light uniformity conversion in a thin profile. By using multiple wavelength conversion layers with different particle types, the system achieves optimal light uniformity without requiring the light emitting units to be positioned at a distance from the light guide plate, thereby reducing overall backlight thickness

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention changes the optical parameters by using wavelength conversion layers with different conversion efficiencies and spectral characteristics. This allows the system to achieve light uniformity through wavelength transformation rather than through spatial separation, effectively reducing the thickness parameter while maintaining optical quality

Inventive Principle:
Principle #35Parameter changes

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 configuration reduces the overall thickness of the backlight, improves light uniformity, and increases flexibility in adjusting the backlight structure while maintaining high optical quality and reducing production costs.

Implementation Method 1

a Quantum Dot (QD) layer on a first surface of the main body... The QD layer includes a plurality of QD blocks

Methodology Applied
Scientific EffectPhotoluminescence: Photoluminescence

Implementation Method 2

The light guide plate further includes a plurality of reflectors on a second surface of the main body... a reflecting surface of each of the plurality of reflectors faces a corresponding QD block

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP3568727B1Backlight and manufacturing method thereof, light guide plate and manufacturing method thereof, and display device
Publication Date: 2024.03.06 BOE TECHNOLOGY GROUP CO LTD
  • EP3568727B1 patent drawingFigure 1-1~1-4
  • EP3568727B1 patent drawingFigure 1-5~1-7
  • EP3568727B1 patent drawingFigure 1-8~1-10

AI summary

A backlight and a manufacturing method thereof, a light guide plate (10) and a manufacturing method thereof, and a display device. The backlight is a direct type backlight, and the backlight includes: a light guide plate (10) having a main body (101) of a plate shape, a plurality of light emitting units (20) that are placed toward to a plane side of the light guide plate (10); where the light guide plate(10) comprises a Quantum Dot (QD) layer (102) on a first surface of the main body (101) wherein the first surface is substantially flat.