Quantum Dot Color Filter for Electronic Paper
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Solution Overview
Problem
Current electronic paper technologies fail to achieve effective color display, particularly due to limitations in ink jet feeding precision for high-resolution ratios and the increased thickness caused by adding color filter units in electrowetting displays, and the lack of color capability in electrophoretic display modes.
Innovation Solution
An active substrate with a color filter layer composed of quantum dot materials emitting red, green, and blue light, combined with a conductive pixel electrode layer and a transparent protective layer, is used to enable color display in electronic paper devices, along with electrophoretic and electrowetting display devices, where the quantum dot material's high intensity and stability ensure efficient light emission and the conductive material enhances brightness, and the thin protective layer maintains the quantum dot material's integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a color filter unit is added above the oil drop layer to realize color display in electrowetting display mode, then color display capability is improved, but the thickness of the product increases significantly
Solution Approach 1:
The patent combines the color filter function directly into the pixel electrode layer by using quantum dot materials that emit different colors (red, green, blue) when excited by ultraviolet light. This integration eliminates the need for separate color filter units above the oil drop layer, thereby achieving color display while maintaining thin product thickness.
Solution Approach 2:
The patent replaces the traditional optical color filtering mechanism with a photoluminescent mechanism using quantum dot materials. Instead of using physical color filter layers that absorb certain wavelengths, the quantum dot layer converts ultraviolet excitation into visible colors through photoluminescence, achieving color display with reduced structural thickness.
2Manufacturing precision
If ink jet feeding precision is increased to achieve high-resolution ratio, then manufacturing complexity and cost increase
Solution Approach 1:
The quantum dot pixel electrode layer is designed to be excitable by ultraviolet light, which is naturally present in ambient environment. This eliminates the need for complex external excitation systems or precise ink jet feeding mechanisms, as the color emission is automatically activated by environmental ultraviolet radiation.
3Illumination intensity
If quantum dot material is used to form the color filter layer, then color display performance and brightness are improved, but the protective layer material selection becomes more restrictive due to temperature sensitivity
Solution Approach 1:
The patent specifies that the protective layer material must have a glass transition temperature greater than the curing temperature of the encapsulant material. This parameter constraint ensures that the protective layer remains stable during the encapsulation process while protecting the temperature-sensitive quantum dot materials, thus resolving the material selection restriction.
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 enables high-performance color display with improved brightness and reduced thickness in electronic paper devices, overcoming the limitations of existing technologies by utilizing quantum dot materials and a conductive pixel electrode layer to efficiently emit primary colors and maintain display quality.
Implementation Method 1
the material of the red sub-pixel unit is a quantum dot material that emits red light when excited by the ambient light; the material of the green sub-pixel unit is a quantum dot material that emits green light when excited by the ambient light; and the material of the blue sub-pixel unit is a quantum dot material that emits blue light when excited by the ambient light
Implementation Method 2
the material of the pixel electrode layer is a conductive material with a reflection coefficient greater than 90%
Data Source
AI summary
The present invention provides an active substrate and a display device for realizing color display of an electronic paper. The active substrate comprises a first substrate and a pixel electrode layer formed on the first substrate, and further comprises a color filter layer formed on the pixel electrode layer and a protective layer formed on the color filter layer, wherein the color filter layer comprises: a red sub-pixel unit, a green sub-pixel unit and a blue sub-pixel unit that are sequentially arranged; wherein the materials of the red sub-pixel unit, the green sub-pixel unit and the blue sub-pixel unit are quantum dot materials that emit red light, green light and blue light respectively when excited by the ambient light. The display device according to the present invention comprises an electrophoretic display device and an electrowetting display device.