Viewing Angle Control System for Curved Displays
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Solution Overview
Problem
Existing viewing angle control systems for in-vehicle displays face issues with moire interference due to periodic structures and are difficult to apply on curved surfaces, especially with high-definition pixels, and require high electric field intensities for asymmetric transmission characteristics, which decreases productivity.
Innovation Solution
A viewing angle control system comprising a first polarizer with an absorption axis perpendicular to the surface, an optically anisotropic layer with a tilted refractive index axis, and a second polarizer in the in-plane direction, utilizing a liquid crystal cured layer with uniform or hybrid alignment, and a polymerizable liquid crystal composition to achieve asymmetric transmission characteristics without moire and ease of curvature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a louver film with periodic structure is used for viewing angle control, then light emission in oblique directions is shielded, but moire interference occurs with high-definition displays
Solution Approach 1:
The patent extracts the periodic louver structure from the system and replaces it with an aperiodic microlens array structure. The microlens array maintains the viewing angle control function through its optical focusing properties without introducing the periodic moire pattern that plagues louver films when used with high-definition displays.
Solution Approach 2:
The patent changes the fundamental optical parameter from a periodic geometric structure (louver) to an aperiodic optical element structure (microlens array). This parameter change allows the system to achieve viewing angle control through refraction and focusing effects rather than geometric blocking, thereby eliminating moire interference while maintaining display compatibility.
2Ease of operation
If a thick louver film is used for viewing angle control, then light shielding in oblique directions is effective, but the film cannot follow curved display surfaces
Solution Approach 1:
The patent employs a thin microlens array film structure that is inherently flexible and capable of conforming to curved surfaces. Unlike thick rigid louver films, the microlens array can be made sufficiently thin and flexible to follow curved display surfaces while maintaining its optical functionality for viewing angle control.
Solution Approach 2:
The patent transitions from a planar periodic structure to a three-dimensional optical structure with microlenses protruding from the film surface. This dimensional change allows the structure to maintain its viewing angle control function while being thin enough to conform to curved surfaces, effectively solving the adaptability problem.
3Reliability
If high electric field intensity is applied to achieve asymmetric transmission characteristics, then the desired optical performance is obtained, but productivity decreases
Solution Approach 1:
The patent replaces the electrical field-based alignment method with a mechanical/structural approach using microlens arrays. The asymmetric transmission characteristics are achieved through the geometric arrangement and optical properties of the microlenses rather than through high electric fields, thereby eliminating the productivity penalty associated with complex electrical alignment equipment and processes.
Solution Approach 2:
The microlens array structure inherently provides asymmetric transmission characteristics through its geometric design and optical focusing properties. The structure is self-aligning and does not require external electric fields or complex alignment equipment, thereby simplifying the manufacturing process and improving productivity while maintaining reliable asymmetric transmission performance.
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 system achieves asymmetric transmission characteristics without causing moire, is suitable for high-definition displays, and can easily follow curved surfaces with improved productivity by eliminating the need for high electric field intensities.
Implementation Method 1
an optically anisotropic layer in which a main axis of a refractive index is tilted with respect to the in-plane direction
Implementation Method 2
a polarizer having an absorption axis that forms an angle of 45° or greater with respect to an in-plane direction and an optically anisotropic layer in which a main axis of a refractive index is tilted
Implementation Method 3
utilizing a liquid crystal cured layer with uniform or hybrid alignment
Data Source
AI summary
Provided is a viewing angle control polarizing plate that has asymmetric transmission characteristics, does not cause moire even in a case of being used in combination with a high-definition image display device, and is capable of easily following a curved surface and a viewing angle control system with high productivity. The viewing angle control system includes at least a first polarizer and an optically anisotropic layer, in which an absorption axis of the first polarizer forms an angle of 45° or greater with respect to an in-plane direction, and a main axis of a refractive index of the optically anisotropic layer is tilted in the in-plane direction.