Liquid Crystal Panel Touch Retardation Alignment
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Solution Overview
Problem
Liquid crystal display devices with touch panels experience decreased bright-place visibility due to increased reflectance when a circularly polarizing plate is retrofitted with a touch panel, as the touch panel's refractive indices cause reflection at its interfaces, and existing solutions fail to adequately address the retardation of the touch panel's support, affecting antireflection performance and contrast ratio.
Innovation Solution
A liquid crystal panel structure that includes an antireflection film, a circularly polarizing plate with a linearly polarizing plate and an out-cell retarder, a touch panel with a support having specific retardation and axis alignment relative to in-cell and out-cell retarders, to suppress external light reflection and maintain good outdoor visibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a circularly polarizing plate is disposed on the liquid crystal panel to suppress reflection and improve bright-place visibility, then outdoor visibility is improved, but when a touch panel is retrofitted, the bright-place visibility decreases due to increased reflectance from the touch panel interfaces
Solution Approach 1:
The patent introduces a retardation compensation film as an intermediary layer between the circularly polarizing plate and the touch panel. This film compensates for the retardation effect caused by the touch panel's support, maintaining the optical path and reducing reflection. The compensation film acts as a mediator that offsets the harmful optical effects of the touch panel interface, preserving bright-place visibility while allowing the touch panel to function.
Solution Approach 2:
The patent changes the optical parameters of the system by introducing a compensation film with specific retardation properties. The film's retardation is designed to counterbalance the retardation introduced by the touch panel support, effectively changing the overall optical path difference. This parameter adjustment allows the system to maintain low reflectance and high visibility despite the presence of the touch panel.
2Adaptability or versatility
If a touch panel is retrofitted to an existing liquid crystal panel, then touch functionality is added, but the contrast ratio and antireflection performance deteriorate due to the touch panel's refractive index mismatch
Solution Approach 1:
The retardation compensation film serves as an intermediary optical element that mitigates the adverse effects of the touch panel's refractive index mismatch. By compensating for the retardation, the film helps maintain the liquid crystal panel's contrast ratio and antireflection properties, allowing touch functionality to be added without sacrificing display quality.
Solution Approach 2:
The patent creates a composite optical structure by combining the liquid crystal panel, circularly polarizing plate, touch panel, and retardation compensation film into an integrated system. This composite structure is designed to work together, where the compensation film's optical properties are specifically tailored to offset the touch panel's negative effects, achieving both touch functionality and maintained contrast ratio.
3Device complexity
If the touch panel's support retardation is not compensated, then the structure remains simple, but the antireflection performance and contrast ratio are affected
Solution Approach 1:
The patent introduces a retardation compensation film as a relatively simple intermediary component that addresses the complex optical interference caused by the touch panel's support. Rather than redesigning the entire touch panel or liquid crystal panel structure, the compensation film provides a straightforward solution that restores antireflection performance with minimal added complexity.
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 proposed structure effectively suppresses external light reflection and maintains high contrast ratios, ensuring good visibility both in bright and dark environments by optimizing the retardation and alignment of the touch panel's support and retarders within the liquid crystal panel.
Implementation Method 1
a circularly polarizing plate is disposed on a surface of a liquid crystal panel to suppress reflection of light therearound (external light)
Implementation Method 2
voltage is applied to the liquid crystal composition to change the alignment of liquid crystal molecules, whereby the amount of light transmitted through the liquid crystal panel is controlled
Implementation Method 3
an antireflection film suppresses the reflection from the panel surface
Implementation Method 4
A color filter substrate suppresses the reflection from the surface of a TFT substrate
Data Source
AI summary
The present invention relates to a liquid crystal panel including in the following order from a viewing surface side: an antireflection film; a circularly polarizing plate including a linearly polarizing plate and an out-cell retarder; a touch panel including a support and a detection electrode; a panel substrate; and an in-cell retarder, the support having a retardation slow axis that forms an angle of 40° to 50° with a slow axis of the in-cell retarder and with a slow axis of the out-cell retarder, the support having a retardation of 3 nm or smaller.