QD Sheet Layout Around UV LEDs for Backlight Color Uniformity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Backlights using ultraviolet LEDs and color conversion sheets, such as quantum dot sheets, face issues with color irregularities due to differences in light source emission direction, leading to uneven white color production.
Innovation Solution
A display device with a backlight configuration where ultraviolet light emitting diodes are arranged in a matrix with a color conversion sheet containing red, green, and blue quantum dots, with specific regions around the LEDs having varying concentrations of these quantum dots to optimize light conversion and reduce color irregularities, including a ring-shaped distribution with more quantum dots in certain areas to correct shifts in color emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a color conversion sheet with uniform quantum dot distribution is used, then the structure is simple and easy to manufacture, but color irregularities occur due to different light path lengths and conversion efficiencies
Solution Approach 1:
The patent applies local quality by creating a non-uniform quantum dot distribution pattern where different regions of the color conversion sheet have different quantum dot densities. Specifically, the quantum dots are distributed more densely in regions closer to the UV LED and less densely in regions farther away, compensating for the varying light path lengths and conversion efficiencies to achieve uniform white light output across the entire display area.
2Illumination intensity
If quantum dots with different conversion efficiencies are used, then the white color can be produced, but color irregularities occur due to differences in light path through the QD sheet
Solution Approach 1:
The patent applies parameter changes by systematically varying the spatial distribution parameters of quantum dots within the color conversion sheet. The quantum dot density is adjusted as a function of position relative to the UV LED, creating a gradient distribution that compensates for the varying optical path lengths. This parameter optimization ensures that regions with longer light paths have higher quantum dot density to maintain consistent conversion efficiency and color uniformity across the display.
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 effectively reduces color irregularities and achieves uniform white light emission by adjusting the distribution of quantum dots, ensuring consistent color output across different light paths and directions.
Implementation Method 1
ultraviolet light emitting diodes are arranged in a plane and in a matrix with a first spacing
Implementation Method 2
red quantum dots that emit red when exposed to ultraviolet light, green quantum dots that emit green when exposed to the ultraviolet light, and blue quantum dots that emit blue when exposed to the ultraviolet light
Data Source
AI summary
The purpose is to reduce a color shift around an ultraviolet LED in a backlight using the ultraviolet LED and a QD sheet, viewed in a plane. The structure is: A display device having a display panel and a backlight, the backlight including a light source in which ultraviolet LEDs are arranged in a plane and in a matrix with a first interval, and a QD sheet covering the light source; the QD sheet being dispersed with red quantum dots, green quantum dots, and blue quantum dots, emitting light in response to ultraviolet light, the QD sheet having a first region and a second region arranged in a ring shape to surround the ultraviolet LED in a plan view, more of the red quantum dots, the green quantum dots, or the blue quantum dots being dispersed in the second region than in the first region.