Reflective Display Panel LC Alignment and Spacer Shape for Dark State
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Solution Overview
Problem
Reflective display panels suffer from light leakage in the dark state due to poor liquid crystal molecule arrangement caused by spacers and residual phase retardation, leading to suboptimal dark state performance.
Innovation Solution
The display panel design includes spacers with specific geometric properties, such as a top surface width to bottom surface width ratio greater than or equal to 0.91 and an included angle between the sidewall and bottom surface greater than 75 degrees, along with liquid crystal molecules aligned at an inclined angle greater than 9 degrees to the substrate surface, reducing residual phase retardation and poor alignment areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If spacers are provided on the reflective surfaces of display pixels, then the display panel can maintain structural integrity and cell gap, but the placement of the spacers causes poor arrangement of the liquid crystal molecules around it, resulting in light leakage in a dark state
Solution Approach 1:
The patent changes the geometric parameters of the spacer, specifically setting the ratio of the top surface width to the bottom surface width to be greater than or equal to 0.91, and the included angle between the sidewall surface and the bottom surface to be greater than 75 degrees. These parameter changes reduce the poor alignment area of liquid crystal molecules around the spacer, thereby reducing light leakage while maintaining structural integrity.
2Reliability
If the residual phase retardation of the liquid crystal layer is present, then the liquid crystal layer can maintain its optical properties, but it causes light leakage in the dark state
Solution Approach 1:
The patent changes the inclination angle parameter of the liquid crystal molecules, specifying that the inclined angle between the molecular long axis and the substrate surface should be greater than 9 degrees. This parameter change reduces the residual phase retardation while maintaining the optical properties of the liquid crystal layer, thereby reducing light leakage in the dark state.
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 design effectively reduces light leakage in the dark state by minimizing residual phase retardation and poor alignment areas, enhancing the display panel's dark state performance.
Implementation Method 1
an inclined angle between a molecular long axis of each of the liquid crystal molecules and a substrate surface of the first substrate is greater than 9 degrees
Implementation Method 2
the residual phase retardation of the liquid crystal layer can easily cause light leakage in the dark state
Data Source
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AI summary
A display panel (10) including a first substrate (SUB1), a second substrate (SUB2), a first alignment layer (AL1), a second alignment layer (AL2), a liquid crystal layer (LCL), a first electrode layer (EL1) and a second electrode layer (EL2) is provided. The first alignment layer (AL1) and the second alignment layer (AL2) are respectively disposed on the first substrate (SUB1) and the second substrate (SUB2). The first electrode layer (EL1) and the second electrode layer (EL2) are used to drive a plurality of liquid crystal molecules (LCM) of the liquid crystal layer (LCL). While the first electrode layer (EL1) and the second electrode layer (EL2) are deactivated, a molecular long axis (MLA) of each liquid crystal molecule (LCM) against a substrate surface (SUBIs) of the first substrate (SUB1) at an inclined angle (0) is greater than 9 degrees. An orthographic projection of the molecular long axis (MLA) on the first substrate (SUB1) or the second substrate (SUB2) is parallel to an alignment direction (AD1, AD2) of the first alignment layer (AL1) or the second alignment layer (AL2).