Transmittance Adjusting Layer for White LED Backlight Color Shift
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Solution Overview
Problem
Conventional backlight modules for liquid crystal displays face issues with color expression, color saturation, and power consumption, particularly with white LEDs, which result in color shift and increased production costs due to limited availability and reduced light transmittance.
Innovation Solution
A display device comprising a backlight module with white LEDs and a transmittance adjusting layer, along with a color filter layer, where the transmittance adjusting layer balances light intensity across different wavelength ranges to prevent color shift and enhance light transmittance without affecting brightness, using a CIE standard illuminant C test to optimize the optical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If white LEDs are used as backlight source, then power consumption is reduced and volume is decreased, but color expression and color saturation deteriorate
Solution Approach 1:
The patent applies local quality by introducing a transmittance adjusting layer with wavelength-dependent transmittance characteristics. This layer selectively adjusts the transmittance of different wavelength components (blue, green, red) to compensate for the spectral deficiencies of white LEDs, thereby improving color expression in specific regions of the spectrum while maintaining the overall energy efficiency benefits of LED backlighting.
Solution Approach 2:
The patent employs parameter changes by modifying the transmittance parameters of the backlight system through the transmittance adjusting layer. By controlling the transmittance values at different wavelengths (Tb, Tg, Tr) to satisfy specific mathematical relationships, the system compensates for the inherent spectral imbalances of white LEDs and achieves improved color saturation and expression without sacrificing power efficiency.
2Stability of the object's composition
If color filter is added to adjust color, then color shift is reduced, but light transmittance and brightness deteriorate
Solution Approach 1:
Instead of using traditional color filters that broadly absorb light, the patent changes the approach by using a transmittance adjusting layer with precisely controlled wavelength-dependent transmittance parameters. This allows selective adjustment of blue, green, and red light components while maintaining higher overall light transmittance and brightness compared to conventional color filter solutions.
Solution Approach 2:
The patent employs composite material structures by combining the transmittance adjusting layer with the liquid crystal display panel and backlight system. This composite structure enables sophisticated control over light transmission characteristics, achieving both color stability and high light transmittance through the synergistic interaction of multiple functional layers with different optical properties.
3Illumination intensity
If transmittance adjusting layer is used to balance light intensity, then color expression is improved, but device complexity increases
Solution Approach 1:
The transmittance adjusting layer serves multiple functions simultaneously: it acts as a spectral balancing element to improve color expression, a light transmission control element to maintain brightness, and a color stability element to prevent color shift. This multi-functionality reduces the need for separate components and simplifies the overall device structure despite the added functional capability.
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 achieves better color expression and maintains or enhances light transmittance, preventing white color shift and reducing production costs by effectively utilizing white LEDs, while ensuring each color output does not suffer from significant color shift and maintaining brightness.
Implementation Method 1
The transmittance adjusting layer has an average transmittance at wavelength being shorter than 495 nm smaller than that at wavelength greater than 570 nm
Implementation Method 2
The display panel includes a color filter layer for filtering the light of the backlight source
Implementation Method 3
The backlight source includes a plurality of white LEDs
Implementation Method 4
white light emitting diodes (LEDs) as the light source
Data Source
AI summary
A high color expression display device and a method for adjusting the displayed color are provided. The display device includes a backlight source, a transmittance adjusting layer, and a display panel for receiving light from the backlight source. The display panel has a color filter disposed above the backlight source. A CIE standard illuminant C test result of the color filter falls into a predetermined scope. In a transmittance spectrum of the transmittance adjusting layer, an average transmittance at wavelength shorter than 495 nm is smaller than that at wavelength greater than 570 nm.