Color Filter Substrate Pigment Alignment for LCD Transmittance
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Solution Overview
Problem
Conventional color filter substrates in liquid crystal displays using organic pigments suffer from low light transmittance and significant color shift due to irregular molecular alignment, leading to light leakage and interference between sub-pixels.
Innovation Solution
Incorporating photosensitive substituents in pigment molecules within the color filter substrate, which undergo photoisomerization, photolysis, or photodimerization reactions under ultraviolet light irradiation to align pigment molecules directionally, thereby improving transmittance and reducing color shift.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If organic pigment is used in color filter substrate, then color filtering function is achieved, but light transmittance is low and color shift occurs due to irregular molecular alignment
Solution Approach 1:
The patent changes the chemical structure parameter of the pigment molecules by introducing photosensitive substituent groups (azobenzene, styryl, or vinylene groups) that can undergo photoisomerization, photolysis, or photodimerization reactions under ultraviolet light irradiation. This structural modification enables the molecules to transition from irregular dispersion to directional alignment, resolving the contradiction between achieving color filtering function and maintaining high light transmittance with uniform molecular alignment
Solution Approach 2:
The patent replaces mechanical or physical mixing methods for pigment dispersion with a photochemical alignment mechanism. By using ultraviolet light irradiation to induce photoisomerization, photolysis, or photodimerization reactions in the photosensitive substituent groups, the pigment molecules self-align directionally without requiring mechanical alignment processes, thereby achieving both high light transmittance and uniform molecular alignment
2Reliability
If pigment molecules are dispersed irregularly, then color resist can be easily manufactured, but light leakage occurs between sub-pixels causing color shift
Solution Approach 1:
The patent enables the pigment molecules to self-align directionally through photochemical reactions. When ultraviolet light irradiates the color resist layer, the photosensitive substituent groups undergo photoisomerization, photolysis, or photodimerization reactions that automatically orient the molecules in a specific direction. This self-service alignment mechanism eliminates the need for complex external alignment equipment while ensuring color accuracy by preventing light leakage between sub-pixels
Solution Approach 2:
The patent incorporates photosensitive substituent groups into the pigment molecule structure in advance during the manufacturing process. This preliminary structural preparation enables the molecules to respond to ultraviolet light irradiation and achieve directional alignment automatically, ensuring color accuracy is maintained without requiring subsequent complex alignment operations
3Reliability
If color resist thickness is increased to reduce color shift, then color filtering performance improves, but module thickness increases
Solution Approach 1:
The patent changes the optical parameter of the pigment molecules by introducing photosensitive substituent groups that enable directional alignment under ultraviolet light. This structural parameter change allows the color resist to achieve superior color filtering performance with aligned molecules, enabling the use of thinner color resist layers and consequently reducing the overall module thickness while maintaining or improving color filtering 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
The directional alignment of pigment molecules enhances light transmittance, reduces power consumption, and minimizes color shift by ensuring coherent light emission, allowing for a thinner module with improved display performance.
Implementation Method 1
the photosensitive substituent carries out a photoisomerization reaction under a function of an ultraviolet light
Implementation Method 2
the photosensitive substituent carries out a photolysis reaction under a function of an ultraviolet light
Implementation Method 3
the photosensitive substituent carries out a photodimerization reaction under a function of an ultraviolet light
Data Source
AI summary
A color filter substrate is disclosed, including a substrate, a black matrix disposed on the substrate and multiple color resist blocks separated by the black matrix and disposed on the substrate. Each color resist block is filled with a color resist material, the color resist material includes pigment molecules, including at least one photosensitive substituent. A liquid crystal display device having the same is also disclosed. Utilizing an UV irradiation step in the CF process, the pigment molecules are aligned directionally, which can increase the transmittance of the color filter substrate, the utilization rate of the backlight, and decrease the power consumption. Under the same display brightness, the thickness of the color filter substrate can be decreased; the pigment molecules aligned directionally can make an emitting light to be along a same direction to reduce the light interference between adjacent sub-pixels having different colors to greatly decrease the color shift.