Light Absorption Anisotropic Layer for Viewing Angle Control
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Solution Overview
Problem
Current viewing angle control systems using light absorption anisotropic layers struggle to provide high image visibility from desired directions while effectively blocking images from other directions, particularly in in-vehicle applications where visibility from driver or passenger seats is compromised, and glare from window glass is not adequately managed.
Innovation Solution
A light absorption anisotropic layer composed of a liquid crystal composition containing a liquid crystalline compound, a dichroic substance, and an alignment agent, with a dichroic substance content of 8.0% or more and a transmittance central axis angle between 5° and 80°, is used in conjunction with a polarizer and an alignment film to control viewing angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a light absorption anisotropic layer with absorption axis in thickness direction is used to control viewing angle, then peeping from unwanted directions is prevented, but image visibility from desired directions (driver or passenger seat) is compromised
Solution Approach 1:
The patent changes the angle parameter of the absorption axis from the conventional 0°-45° range to a specific 5°-80° range relative to the film surface normal. This parameter modification enables the layer to maintain high light absorption for unwanted directions while preserving sufficient image visibility for desired viewing angles, thereby resolving the contradiction between preventing peeping and maintaining image quality.
Solution Approach 2:
The patent creates different optical properties for different spatial directions by controlling the absorption axis orientation. The light absorption anisotropic layer exhibits direction-dependent light absorption characteristics, providing strong absorption for unwanted viewing angles while maintaining transparency for desired viewing angles, thus addressing the contradiction locally for different spatial directions.
2Object-affected harmful factors
If the light absorption anisotropic layer blocks light at angles other than the specific direction, then viewing angle control is improved, but the layer requires sufficient absorption which conflicts with maintaining image visibility
Solution Approach 1:
By precisely controlling the absorption axis angle parameter within 5°-80° and optimizing the dichroic substance content (8.0% or more), the patent achieves a balance where the layer blocks light at unwanted angles while maintaining sufficient image brightness from desired directions. This parameter optimization resolves the contradiction between light blocking capability and image illumination quality.
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 solution ensures high image visibility from desired directions while effectively blocking images from other directions, improving visibility and reducing glare, by optimizing the alignment and content of the dichroic substance within the light absorption anisotropic layer.
Implementation Method 1
a light absorption anisotropic layer which has an absorption axis in a thickness direction... a liquid crystal composition containing a liquid crystalline compound, a dichroic substance... an angle between an absorption axis and a normal line of a film surface is 0° to 45°
Implementation Method 2
a light absorption anisotropic layer formed of a liquid crystal composition containing a liquid crystalline compound, a dichroic substance, and an alignment agent
Data Source
AI summary
A light absorption anisotropic layer used in a viewing angle control system which has high image visibility from a desired direction and can sufficiently block images from other directions, an optical film, a viewing angle control system, and an image display device using the light absorption anisotropic layer. The light absorption anisotropic layer is formed of a liquid crystal composition containing a liquid crystalline compound, a dichroic substance, and an alignment agent, in which a content of the dichroic substance is 8.0% by mass or more with respect to a total solid content mass of the liquid crystal composition, and an angle θ between a transmittance central axis of the light absorption anisotropic layer and a normal direction of a surface of the light absorption anisotropic layer is 5° or more and less than 80°.