Modified Pigment Black Matrix for High Resistivity LCDs
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Solution Overview
Problem
Current black matrix materials in liquid crystal displays face challenges in achieving a balance between high resistivity and optical density, with chromium-based films being expensive and environmentally restrictive, and carbon black pigments failing to provide the desired electrical properties.
Innovation Solution
A curable coating composition containing a modified pigment with attached organic groups, such as -X-I or -X-NI, is used to form a black matrix, where X represents an arylene or heteroarylene group, and I represents a non-polymeric ionic or ionizable group, achieving high volume resistivity and optical density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If chromium-based films are used for black matrix, then light-shielding capability is improved, but cost increases and environmental restrictions apply
Solution Approach 1:
The patent replaces expensive chromium-based materials with organic pigment dispersions that can be applied as disposable coating layers. These organic-based black matrix layers achieve comparable light-shielding performance without the high cost and environmental restrictions associated with chromium vapor deposition processes
Solution Approach 2:
The patent changes the material composition parameters from inorganic chromium-based films to organic pigment-based dispersions. By adjusting pigment concentration, particle size, and dispersion medium composition, the patent achieves optimal light-shielding capability while maintaining low cost and environmental compatibility
2Illumination intensity
If chromium films are used for black matrix, then light-shielding capability is improved, but electrical design flexibility deteriorates due to low resistivity
Solution Approach 1:
The patent changes the electrical resistance parameter by using organic pigment-based materials instead of chromium films. The organic polymer matrix and pigment composition can be tuned to achieve high volume resistivity (≥10^12 ohm-cm), enabling flexible electrical design configurations in LCD devices while maintaining excellent light-shielding performance
3Reliability
If carbon black pigment is used to increase resistivity, then electrical properties are improved, but optical density deteriorates
Solution Approach 1:
The patent uses composite materials consisting of carbon black pigment particles dispersed in a polymer matrix. This composite structure allows the carbon black to provide high electrical resistivity while the polymer matrix and pigment morphology maintain high optical density. The synergistic combination of pigment and polymer achieves both electrical and optical performance requirements
Solution Approach 2:
The patent optimizes the local distribution and morphology of carbon black particles within the polymer matrix. By controlling particle size, dispersion uniformity, and aggregation state, the patent ensures that electrical resistivity is maximized at critical locations while maintaining overall high optical density across the black matrix layer
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 modified pigment-based black matrix exhibits resistivity of at least 10^12 ohm-cm and optical density of greater than 3 at 1 micron thickness, offering improved electrical properties and environmental sustainability.
Implementation Method 1
the modified pigment comprises a pigment having attached at least one organic group having the formula -X-I or -X-NI, wherein X, which is directly attached to the pigment, represents an arylene or heteroarylene group, an alkylene group, an aralkylene group, or an alkarylene group, I represents a non-polymeric group comprising at least one ionic group or at least one ionizable group
Data Source
AI summary
The present invention relates to a black matrix formed by applying a curable coating composition onto a substrate to form a curable coating, curing the curable coating imagewise to form a coating, and developing and drying the coating. The curable coating composition comprises a vehicle, a curable resin, and at least one modified pigment comprising a pigment having attached at least one organic group having the formula -X-I or -X-NI, wherein X, which is directly attached to the pigment, represents an arylene or heteroarylene group, an alkylene group, an aralkylene group, or an alkarylene group, I represents a non-polymeric group comprising at least one ionic group or at least one ionizable group, and NI represents a non-polymeric group comprising at least one nonionic group. The curable coating composition, curable coating, and cured coating are also described. Also disclosed is a method of controlling the resistivity of a coating.