Quantum Dot Backlight Layout for Fine Local Dimming
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Solution Overview
Problem
Liquid crystal display devices face challenges in achieving high contrast and fine local dimming due to issues like 'chip visibility' and reduced front luminance when using multiple diffusion sheets, which hinder accurate local dimming and image quality.
Innovation Solution
A backlight design incorporating quantum dots and short-wavelength LEDs, arranged in specific configurations to enhance light distribution and conversion, reducing the need for additional diffusion sheets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If multiple diffusion sheets with large diffusion effects are used to prevent chip visibility, then chip visibility is reduced, but fine local dimming cannot be performed and front luminance is reduced
Solution Approach 1:
The patent divides the backlight system into multiple independent LED units, each with its own color conversion layer. This segmentation allows each LED unit to be controlled independently for fine local dimming while the overall arrangement prevents chip visibility through distributed light emission patterns.
Solution Approach 2:
The patent applies different properties to different parts of the system: LED units are arranged with specific spacing and emission patterns in some regions to prevent chip visibility, while color conversion layers are positioned close to individual LEDs in other regions to enable fine local dimming control without requiring multiple diffusion sheets.
2Object-affected harmful factors
If multiple diffusion sheets with large diffusion effects are used to prevent chip visibility, then chip visibility is reduced, but front luminance is reduced
Solution Approach 1:
The patent extracts the diffusion function from separate diffusion sheets and integrates it into the color conversion layers positioned close to each LED. This eliminates the need for multiple thick diffusion sheets that reduce front luminance while still achieving chip visibility prevention through the distributed LED arrangement.
3Measurement precision
If pixel size is reduced to achieve high definition, then resolution is improved, but image contrast is reduced
Solution Approach 1:
The patent implements dynamic local dimming control where each LED unit can be independently adjusted in brightness. This dynamic control allows the system to maintain high resolution with small pixels while compensating for contrast loss by selectively dimming or brightening specific LED units based on image content requirements.
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 proposed backlight design effectively addresses 'chip visibility' and maintains high front luminance while enabling fine local dimming, enhancing image contrast and quality without relying on excessive diffusion sheets.
Implementation Method 1
first red quantum dots that receive blue light and emit red light, and first green quantum dots that receive blue light and emit green light are dispersed in the color conversion sheet
Implementation Method 2
a light source in which blue LEDs are planarly arranged in a matrix
Data Source
AI summary
A backlight includes a light source in which blue LEDs are planarly arranged in a matrix with a first interval, and a color conversion sheet disposed covering the light source. First red quantum dots that receive blue light and emit red light, and first green quantum dots that receive blue light and emit green light are dispersed in the color conversion sheet. An RG quantum dot layer, in which second red quantum dots that receive blue light and emit red light and second green quantum dots that receive blue light and emit green light are dispersed, is disposed around each of the blue LEDs in planar view.