Compensation Layer for LCD Polarization Alignment
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Solution Overview
Problem
Liquid Crystal Display (LCD) panels experience light leakage and uneven display due to twist and deformation of glass substrates, which alter the polarization state of light, leading to incomplete absorption in the dark state.
Innovation Solution
A compensation layer is introduced between the upper substrate and the liquid crystal layer, made of materials like cyclic olefin polymers or polycarbonates, to convert the polarization direction of light exiting the upper substrate to match the original polarization direction before incident on the lower substrate, ensuring complete absorption and preventing light leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If glass substrates are used in LCD panels, then structural support and protection are provided, but twist and deformation of the substrates alter the polarization state of light, causing light leakage and uneven display in the dark state
Solution Approach 1:
The patent introduces a compensation layer as an intermediary component between the upper substrate and the liquid crystal layer. This compensation layer specifically addresses the harmful effect of substrate deformation by providing optical compensation that counteracts the altered polarization state, thereby eliminating light leakage and improving display uniformity without requiring changes to the glass substrate itself
Solution Approach 2:
The patent employs a compensation layer with specific optical parameters (retardation value and optical axis orientation) that are designed to counteract the deformation-induced changes in the liquid crystal layer. By carefully selecting and controlling these parameters, the system compensates for substrate deformation effects and maintains proper polarization state for uniform dark state display
2Illumination intensity
If the absorbing axes of the lower and upper polarizers are orthogonal to achieve high contrast ratio, then light absorption in the dark state is maximized, but any deviation in polarization direction due to substrate deformation prevents complete absorption and causes light leakage
Solution Approach 1:
The compensation layer serves as a mediator between the polarizers and the deformed liquid crystal layer, restoring the correct polarization direction of light before it reaches the upper polarizer. This ensures that the orthogonal absorbing axes configuration works effectively even when substrate deformation occurs, maintaining both high contrast ratio and uniform dark state
Solution Approach 2:
The compensation layer performs preliminary correction of the polarization state by counteracting the deformation effects before the light reaches the upper polarizer. This preliminary anti-action prevents the polarization direction deviation that would otherwise cause light leakage, ensuring complete absorption and uniform dark state display
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 compensation layer effectively inhibits light leakage and achieves uniform display by aligning the polarization direction of light exiting the upper substrate with the original polarization direction, maintaining high contrast ratio and minimizing light leakage caused by glass substrate deformation.
Implementation Method 1
an optical phase compensation member is disposed for canceling birefringence of the polarizing plate supporting base material
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
A display panel and a display device are disclosed. The display panel comprises a lower substrate (1), an upper substrate (2) and a liquid crystal layer (3) disposed between the upper substrate (2) and the lower substrate (1), a lower polarizer (4) is disposed at a light incident side of the lower substrate (1), an upper polarizer (5) is disposed at a light exiting side of the upper substrate (2). The display panel further comprises a compensation layer (6) disposed between the upper substrate (2) and the liquid crystal layer (3) and configured to compensate for a residual birefringence of the substrates (1, 2) so that, in the dark display state, the polarization direction of light exiting the upper substrate (2) remains the same as the polarization direction of light before incident on the lower substrate (1).