Quantum Dot Film With Gradient Refractive Index Waveguide
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Solution Overview
Problem
The color gamut of Liquid Crystal Displays (LCDs) is reduced and color deviation occurs at wide viewing angles due to the varying optical paths of light through a quantum dot film when illuminated by LEDs at non-vertical angles, leading to suboptimal display performance.
Innovation Solution
A quantum dot film with an optical waveguide layer composed of laminated sublayers with decreasing refractive indices, positioned between the light guide plate and the quantum dot layer, corrects the incident light angle to ensure it enters the quantum dot layer more perpendicularly, enhancing the color gamut and reducing color deviation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If light is incident on the quantum dot film in a non-vertical direction after passing through the light guide plate, then the optical path of light in the quantum dot film becomes longer, but this causes color gamut reduction and color deviation at wide viewing angles
Solution Approach 1:
The optical waveguide layer is divided into multiple sublayers with different refractive indices (first sublayer with refractive index n1, second sublayer with refractive index n2, where n1 > n2). This segmentation allows different portions of incident light to be refracted at different angles, collectively redirecting oblique light rays toward vertical incidence on the quantum dot layer, thereby resolving the color deviation issue at wide viewing angles while maintaining broad color gamut coverage.
Solution Approach 2:
The patent changes the refractive index parameter across different sublayers of the optical waveguide layer. By creating a gradient refractive index structure (n1 > n2), the system transforms the optical path of incident light, causing oblique light to refract progressively toward the vertical direction as it passes through successive sublayers. This parameter change effectively corrects the incident angle without requiring mechanical adjustment, thereby improving viewing angle performance while preserving color accuracy.
2Manufacturing precision
If the optical waveguide layer uses a laminated structure with multiple sublayers, then the light incident angle correction becomes more effective, but the device complexity increases
Solution Approach 1:
The patent extracts the light incident angle correction function from the quantum dot film itself and places it in a separate optical waveguide layer. This functional extraction allows the quantum dot layer to focus solely on color emission while the optical waveguide layer handles light direction control. The optical waveguide layer is further divided into sublayers with different refractive indices, creating a modular structure that improves manufacturing precision for angle control while managing complexity through functional separation.
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 ensures that light passes through the quantum dot layer in a shorter optical path, thereby improving the color gamut and minimizing color deviation at wide viewing angles, resulting in enhanced display performance.
Implementation Method 1
said optical wave guide layer is a laminated structure made up of a plurality of sublayers, and starting from the sublayer close to said quantum dot film layer in the laminated structure, the refractive indices of sublayer becomes smaller layer by layer
Implementation Method 2
the quantum dots can emit light upon excitation with light emitted by the LED. Light emitted by quantum dots and the LED can form white light after mixing
Data Source
AI summary
The present disclosure provides a quantum dot film, a method for manufacturing the same and a backlight module. The quantum dot film comprises a quantum dot layer and an optical waveguide layer, the quantum dot layer covers the optical waveguide layer, the optical waveguide layer is a laminated structure made up of a plurality of sublayers, and starting from the sublayer close to the quantum dot layer in the laminated structure, the refractive indices of sublayers become larger layer by layer. The backlight module comprises the above-mentioned quantum dot film, and the quantum dot film is located between the optical waveguide layer and the prism film.