Display Panel Asymmetric Pretilt Alignment Color Shift
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Solution Overview
Problem
Conventional liquid crystal display panels experience color shift due to differences in refractive indexes and phase retardations when viewed from different angles, affecting display quality and aperture ratio.
Innovation Solution
A display panel design with a liquid crystal layer comprising liquid crystal molecules aligned at an acute angle between two alignment films, along with compensation films to equalize phase retardations, maintaining a pretilt angle and twist angle sum of zero to minimize color shift without affecting aperture ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If liquid crystal molecules are aligned perpendicular to substrates with conventional alignment films, then the liquid crystal layer provides sufficient phase retardation, but color shift occurs under various viewing angles
Solution Approach 1:
The patent applies asymmetry by configuring the alignment films to create different pretilt angles at the first and second substrates. Specifically, the first alignment film forms a first pretilt angle while the second alignment film forms a second pretilt angle, where the sum of these angles equals zero. This asymmetric configuration compensates for phase retardation differences caused by viewing angle variations, thereby reducing color shift without requiring additional compensation films that would reduce aperture ratio.
Solution Approach 2:
The patent changes the pretilt angle parameters of the liquid crystal molecules at each substrate interface. By adjusting the pretilt angles to specific ranges (first pretilt angle between 0-5 degrees, second pretilt angle between -5-0 degrees) and ensuring their sum equals zero, the patent optimizes the liquid crystal alignment to compensate for viewing angle effects on phase retardation, improving color stability across different viewing angles.
2Reliability
If compensation films are added to correct phase retardation differences, then color shift is reduced, but aperture ratio decreases
Solution Approach 1:
The patent extracts the color compensation function from separate compensation films and integrates it into the alignment films themselves. By configuring the alignment films to provide specific pretilt angles whose sum equals zero, the patent achieves phase retardation compensation directly through the liquid crystal alignment, eliminating the need for additional compensation films and thereby maintaining high aperture ratio while improving color stability.
3Adaptability or versatility
If liquid crystal molecules are aligned at large angles to substrates, then viewing angle is improved, but light transmittance decreases
Solution Approach 1:
The patent optimizes the pretilt angle parameters to small values (first pretilt angle between 0-5 degrees, second pretilt angle between -5-0 degrees) rather than large angles. This parameter optimization achieves sufficient viewing angle performance while minimizing the impact on light transmittance, as smaller pretilt angles maintain better optical alignment with the incident light direction.
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 effectively compensates for phase retardation differences, improving color stability and viewing angles while maintaining high light transmittance and aperture ratio, reducing chromatic aberration and enhancing display quality.
Implementation Method 1
The liquid crystal layer comprises a column of liquid crystal molecules arranged along the third direction, and the column of liquid crystal molecules comprises a first liquid crystal molecule closest to the first alignment film and a second liquid crystal molecule closest to the second alignment film
Implementation Method 2
On a plane defined by the first direction and the second direction, an orthographic projection of a long axis of the first liquid crystal molecule is arranged at an acute angle to an orthographic projection of a long axis of the second liquid crystal molecule
Data Source
AI summary
A display panel, a display device, and a method for manufacturing a display panel are provided. The display panel includes first and second substrates, first and second alignment films and a liquid crystal layer extending along a first direction and a second direction and sequentially along a third direction perpendicular to the first direction and the second direction. The liquid crystal layer includes a column of liquid crystal molecules along the third direction, and includes a first liquid crystal molecule closest to the first alignment film and a second liquid crystal molecule closest to the second alignment film. The first liquid crystal molecule and the second liquid crystal molecule have different tilting tendencies with respect to the plane defined by the first direction and the second direction, and form a twist angle.