Inkjet Cholesteric Liquid Crystal Layers for Reflective Displays
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Solution Overview
Problem
The manufacturing process of reflective layers in LCD devices is complex and costly, particularly due to the use of Chemical Vapor Deposition (CVD) methods for forming cholesteric liquid crystal layers, which increases the production costs of these devices.
Innovation Solution
The use of an inkjet process to form cholesteric liquid crystal layers instead of CVD, combined with a reflective layer structure that includes wavelength conversion layers and a transmissive layer, reduces manufacturing costs and improves reflectance by employing cholesteric liquid crystal layers with impurities and a planarization layer, allowing for efficient light conversion and polarization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If Chemical Vapor Deposition (CVD) method is used to form cholesteric liquid crystal layers, then the reflectance and optical performance are improved, but the manufacturing cost and process complexity increase significantly
Solution Approach 1:
The patent replaces the Chemical Vapor Deposition (CVD) process with a solution-based coating method. Instead of using complex vapor phase chemical reactions, the cholesteric liquid crystal composition is applied as a solution that is then cured to form the reflective layer. This substitution of manufacturing approach significantly simplifies the process while maintaining the optical functionality of the cholesteric liquid crystal layer.
Solution Approach 2:
The patent changes the physical and chemical parameters of the cholesteric liquid crystal layer by incorporating specific impurities (such as nematic liquid crystals or chiral dopants) that enable the layer to achieve the desired reflectance properties through solution coating rather than requiring CVD processing. This parameter modification allows the material to self-organize into the necessary cholesteric structure during curing.
2Reliability
If CVD process is used for forming cholesteric liquid crystal layers, then the optical quality is enhanced, but the manufacturing cost increases
Solution Approach 1:
The patent employs a cost-effective solution-based coating method instead of expensive CVD equipment and materials. The cholesteric liquid crystal composition is formulated as a solution that can be applied using conventional coating techniques, eliminating the need for costly CVD infrastructure while producing optically functional layers suitable for display applications.
Solution Approach 2:
The cholesteric liquid crystal solution is designed to self-organize into the required cholesteric structure during the curing process, without requiring complex CVD processing steps. The impurities and additives in the solution facilitate spontaneous molecular arrangement, allowing the material to self-form the optical structure needed for reflectance functionality.
3Illumination intensity
If multiple layers with wavelength conversion materials are added to improve color purity and light efficiency, then the optical performance is enhanced, but the device structure becomes more complex
Solution Approach 1:
The patent combines multiple functional layers (wavelength conversion layers, cholesteric liquid crystal layers, and planarization layers) into an integrated structure where each layer performs multiple functions. The wavelength conversion layers not only convert light wavelengths but also contribute to the overall optical path management, while the cholesteric liquid crystal layers provide both reflection and structural organization, reducing the need for separate dedicated layers for each function.
Solution Approach 2:
The cholesteric liquid crystal layers serve multiple purposes: they act as reflective layers for specific wavelengths, provide structural organization for the liquid crystal molecules, and contribute to the planarization of the display structure. This multi-functionality reduces the total number of separate layers needed, simplifying the overall device architecture while maintaining enhanced optical performance.
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 enables the production of display devices with improved reflectance and reduced manufacturing costs by simplifying the manufacturing process and utilizing inkjet technology for cholesteric liquid crystal layer formation, enhancing light output efficiency and color purity.
Implementation Method 1
a first cholesteric liquid crystal layer disposed on a surface of the first wavelength conversion layer facing the first substrate, a second cholesteric liquid crystal layer disposed on a surface of the second wavelength conversion layer facing the first substrate
Implementation Method 2
a first wavelength conversion layer disposed on a surface of the second substrate facing the first substrate, and overlapping the first sub-pixel electrode, a second wavelength conversion layer disposed on the surface of the second substrate facing the first substrate, and overlapping the second sub-pixel electrode
Data Source
AI summary
A display device including a first substrate, a pixel unit disposed on the first substrate and including a first sub-pixel electrode, a second sub-pixel electrode and a third sub-pixel electrode, the first through third sub-pixel electrodes being adjacent to one another, a second substrate facing the first substrate, a first wavelength conversion layer disposed on a surface of the second substrate facing the first substrate, and overlapping the first sub-pixel electrode, a second wavelength conversion layer disposed on the surface of the second substrate facing the first substrate, and overlapping the second sub-pixel electrode, a transmissive layer disposed on the surface of the second substrate facing the first substrate, and overlapping the third sub-pixel electrode, a first cholesteric liquid crystal layer disposed on a surface of the first wavelength conversion layer facing the first substrate, a second cholesteric liquid crystal layer disposed on a surface of the second wavelength conversion layer facing the first substrate, and a planarization layer disposed on the surfaces of the first and second cholesteric liquid crystal layers facing the first substrate and on a surface of the transmissive layer facing the first substrate. Methods of manufacturing a display device capable of reducing the number of process steps in the manufacturing process are also disclosed.