Green Filter Light Leakage Reduction via Spectral Control
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Solution Overview
Problem
Current color filters in display products, such as LCDs, suffer from light leakage in the red light region due to material characteristics, affecting chromaticity coordinates and display quality, which cannot meet market demands for high resolution and contrast.
Innovation Solution
A display module is designed with a green filter layer where the ratio of light energy between 660 nm and 780 nm wavelengths to the total energy between 380 nm and 780 nm is controlled by adjusting the spectrum of the light source, using materials like red fluorescent powders, red light emitting diodes, or OLEDs to reduce the transmittance intensity in the red light region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional color filters are used, then the display can show colors, but light leakage occurs in the red light region affecting chromaticity coordinates and display quality
Solution Approach 1:
The patent applies parameter changes by optimizing the spectral power distribution parameters of the light source. Specifically, it controls the ratio of red light energy (660-780nm) to total visible light energy (380-780nm) to be less than 2%, and adjusts the peak wavelength and full width at half maximum of the green light spectrum to achieve minimal light leakage through the green filter layer while maintaining display quality
Solution Approach 2:
The patent uses composite materials by combining specific fluorescent powders (yellow, orange, red) with a blue light emitting diode. This composite light source system produces a controlled spectrum that minimizes red light content, thereby reducing light leakage when passing through the green filter layer while still providing full-color display capability
2Illumination intensity
If the green filter layer transmits more light, then the display brightness increases, but light leakage in the red region increases affecting chromaticity accuracy
Solution Approach 1:
The patent changes the spectral parameters of the light source to have a lower red light component (less than 2% energy ratio in 660-780nm range). This allows the green filter layer to transmit more light for higher brightness while the reduced red light content prevents excessive light leakage, thereby maintaining accurate chromaticity coordinates
Solution Approach 2:
The patent introduces the controlled spectral distribution as an intermediary between the light source and the green filter layer. By mediating the spectral content (specifically reducing red light wavelengths), it enables the filter to transmit sufficient light for brightness while blocking excessive red light that would cause chromaticity errors
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 approach significantly reduces light leakage, improving display quality by minimizing the displacement in chromaticity coordinates of white dots and enhancing the overall color display effect.
Implementation Method 1
a green filter layer... disposed on the first substrate or the second substrate. A spectrum between 380 nm and 780 nm of wavelength of the light source passing through the green filter layer corresponds to a first energy. A spectrum between 660 nm and 780 nm of wavelength of the light source passing through the green filter layer corresponds to a second energy
Implementation Method 2
A spectrum between 380 nm and 780 nm of wavelength of the light source passing through the green filter layer corresponds to a first energy. A spectrum between 660 nm and 780 nm of wavelength of the light source passing through the green filter layer corresponds to a second energy. A ratio of the second energy to the first energy is less than 2%
Data Source
AI summary
A display module having a light source includes a display unit. The display unit includes a first substrate, a second substrate opposite to the first substrate, a display medium and a green filter layer. The display medium is disposed between the first substrate and the second substrate. The green filter layer is disposed on the first substrate or the second substrate. When the wavelength of the light is between 380 nm and 780 nm, the spectrum of the light source passing through the green filter layer corresponds to a first energy. When the wavelength of the light is between interval of 660 and 780 nm, the spectrum of the light source passing through the green filter layer corresponds to a second energy. The ratio of the second energy to the first energy is less than 2%.