Liquid Crystal Display Polarizing Plate Corner Stress Relief
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Solution Overview
Problem
Conventional heteromorphic liquid crystal displays with polarizing plates are prone to cracking at peripheral portions when subjected to thermal shock due to compression residual stresses, which can lead to reduced yield and reliability.
Innovation Solution
The polarizing plates in the liquid crystal display are designed with specific shapes and orientations, where peripheral and corner portions are not fixed to the liquid crystal cell, allowing them to lie freely, thereby minimizing stress application during thermal shocks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polarizing plates are applied onto the main surface of the liquid crystal cell in a conventional heteromorphic liquid crystal display, then the liquid crystal display can be assembled and function, but the peripheral portions of the polarizing plates are likely to crack when thermal shock is applied
Solution Approach 1:
The patent extracts the problematic peripheral portions (corner portions and portions along tilted sides) from the bonding arrangement. These portions are deliberately left unbonded to the liquid crystal cell, allowing them to be removed from the stress system. This extraction prevents the transmission of thermal stress to these vulnerable areas, thereby preventing cracks while maintaining the functionality of the bonded regions.
Solution Approach 2:
The patent segments the bonding arrangement into two distinct zones: bonded regions (on sides extending perpendicular to the absorption axis or slow axis) and unbonded regions (corner portions and portions along tilted sides). This segmentation allows different parts of the polarizing plate to have different bonding states, with unbonded segments serving as stress relief zones that prevent crack propagation during thermal shock.
2Stability of the object's composition
If peripheral portions of polarizing plates are fixed onto the liquid crystal cell, then assembly is complete and structural integrity is maintained, but stress concentration occurs at corner and tilted side portions during thermal shock
Solution Approach 1:
The patent introduces unbonded peripheral portions as intermediary stress relief zones between the bonded regions and the external environment. These unbonded portions act as buffers that absorb and redistribute thermal stress, preventing stress concentration at corner and tilted side portions. The bonded central regions maintain structural integrity while the unbonded peripheral regions serve as stress mediators.
3Adaptability or versatility
If the liquid crystal display uses a planar non-rectangular shape for higher added value, then design flexibility and application versatility improve, but the polarizing plates become more susceptible to cracking
Solution Approach 1:
The patent applies local quality by differentiating the bonding characteristics across different regions of the polarizing plate. Corner portions and portions along tilted sides are left unbonded (different local property), while portions on sides extending perpendicular to the absorption axis or slow axis are bonded. This localized differentiation allows the display to achieve non-rectangular shapes with high design flexibility while maintaining reliability by protecting vulnerable regions from stress.
Data Source
AI summary
In a liquid crystal display, a liquid crystal cell and a polarizing plate respectively have a planar, non-rectangular shape. The polarizing plate has an axis that is either an absorption axis or a slow axis. The planar shape of the polarizing plate includes first and second sides respectively extending in a direction perpendicular to the axis and a direction tilted from the axis. The polarizing plate includes first and second peripheral portions respectively lying along the first and second sides, and includes a corner portion lying at a portion where the first and second peripheral portions overlap each other. The polarizing plate is applied by a bonding agent onto a main surface of the liquid crystal cell so that the corner portion is not coupled to the main surface. A contour portion extending in a direction tilted from the axis may not be coupled to the main surface.