Reflective Display Structure Using Quantum Dots for Brighter Color Images
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Solution Overview
Problem
Traditional reflective display devices face challenges in achieving sufficient brightness when displaying color images due to the significant reduction of light transmission through color resist layers, resulting in low reflectivity.
Innovation Solution
Incorporation of quantum dots between the optical layer and electrophoretic display module, with a color filter layer having openings and specific fill rates, to enhance light transmission and reflection, thereby improving brightness and reflectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a color resist layer is disposed above the electrophoretic display module to enable color image display, then the display device can show color images, but the light transmission is significantly reduced resulting in low reflectivity and insufficient brightness
Solution Approach 1:
The patent introduces a quantum dot layer as an intermediary between the color filter layer and the electrophoretic display module. The quantum dots convert incident light into specific wavelengths that match the color resist absorption characteristics, enabling efficient color generation while maintaining high light transmission. This mediator layer resolves the contradiction by decoupling the color generation function from the light blocking function of traditional color filters.
Solution Approach 2:
The patent changes the optical parameters of the display structure by replacing conventional color filters with a quantum dot-based color conversion system. The quantum dots have size-tunable emission wavelengths and high photoluminescence quantum yield, fundamentally changing how color is generated in the display device. This parameter change enables simultaneous achievement of color display capability and high brightness.
2Adaptability or versatility
If a color resist layer is used to achieve color display, then color images can be displayed, but the reflectivity decreases from about 24% to only about 10%
Solution Approach 1:
The quantum dot layer serves as an optical intermediary that converts broad-spectrum incident light into narrow-band emission at specific wavelengths. This conversion process occurs before light reaches the color resist layer, allowing the color resist to selectively transmit only the required color wavelengths while reflecting or absorbing others, thereby dramatically improving overall reflectivity while maintaining color display function.
Solution Approach 2:
The patent creates a composite optical structure combining quantum dots with the electrophoretic display module and color filter layer. This composite system leverages the high quantum yield of quantum dots, the reflective properties of the electrophoretic module, and the wavelength-selective properties of the color filter to achieve both color display and high reflectivity simultaneously.
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 configuration increases light transmission by 30% to 50% and reflectivity by 1.2 to 2 times, overcoming the brightness limitations of traditional reflective display devices.
Implementation Method 1
When first light passes through the optical layer and transmits to the quantum dot, the quantum dot emits second light
Implementation Method 2
the electrophoretic display module is configured to reflect the second light to irradiate outwards from the color filter layer
Data Source
AI summary
A reflective display device includes an electrophoretic display (EPD) module, an optical layer, a color filter layer, and at least one quantum dot (QD). The optical layer is located above the electrophoretic display module. The color filter layer is located on the optical layer. The quantum dot is located between the optical layer and the electrophoretic display module. When first light passes through the optical layer and transmits to the quantum dot, the quantum dot emits second light, and the electrophoretic display module is configured to reflect the second light to irradiate outwards from the color filter layer.