Optical Laminate Louver Bias Angle Moire Suppression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Liquid crystal display apparatuses face issues with moire occurrence, insufficient viewing angle characteristics, and brightness degradation due to the use of louver films, which affect image quality and usability, especially in on-board applications.
Innovation Solution
An optical laminate is developed with a light-diffusing pressure-sensitive adhesive layer and a matte layer, where the pressure-sensitive adhesive has a refractive index of 1.47 to 1.60 and includes light-diffusible fine particles with a refractive index difference, combined with a louver layer having a bias angle between 2° and 6°, optimizing haze value and bias angle to suppress moire and enhance brightness and viewing angle characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a louver film is used to prevent display image reflection on windshields, then the reflection problem is solved, but image quality is significantly degraded by occurrence of moire and insufficient viewing angle characteristic
Solution Approach 1:
The patent applies composite materials by combining a louver layer with a light-diffusing layer containing specific resin materials (acrylic resin, styrene resin, or their copolymers) and light-diffusible fine particles. This composite structure achieves both the reflection prevention function of the louver layer and the moire suppression function of the light-diffusing layer, resolving the contradiction between preventing display image reflection and maintaining image quality.
Solution Approach 2:
The patent changes physical parameters by specifying the refractive index of the pressure-sensitive adhesive (1.30 to 1.70) and the refractive index difference between fine particles and adhesive (0.01 to 0.30), as well as optimizing the bias angle of the louver layer (2° to 6°) and haze value (20% to 60%). These parameter optimizations enable simultaneous achievement of reflection prevention and high image quality by controlling light diffusion and refraction characteristics.
2Object-affected harmful factors
If a louver film is used to prevent display image reflection, then the reflection problem is solved, but brightness and viewing angle characteristics are insufficient
Solution Approach 1:
The patent optimizes brightness by controlling the haze value of the light-diffusing layer within 20% to 60% and adjusting the refractive index of the pressure-sensitive adhesive (1.30 to 1.70). These parameter changes ensure sufficient light transmission and diffusion, achieving both reflection prevention and high brightness performance.
Solution Approach 2:
The composite structure of the louver layer and light-diffusing layer works synergistically to maintain brightness. The louver layer prevents reflection while the light-diffusing layer with optimized refractive index and haze value ensures adequate light transmission, resolving the contradiction between reflection prevention and brightness.
3Object-affected harmful factors
If a louver film is used to prevent display image reflection, then the reflection problem is solved, but viewing angle characteristic is insufficient
Solution Approach 1:
The patent improves viewing angle characteristics by optimizing the bias angle of the louver layer to 2° to 6° and controlling the haze value of the light-diffusing layer at 20% to 60%. These parameter changes enable light to be diffused uniformly across different viewing angles while maintaining the reflection prevention function of the louver structure.
Solution Approach 2:
The composite structure combines the directional light control of the louver layer with the uniform light diffusion of the light-diffusing layer. This combination achieves both reflection prevention and wide viewing angle characteristics by complementing the strengths of each layer.
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 optical laminate effectively suppresses moire occurrence and improves brightness and viewing angle characteristics, providing a balanced performance suitable for on-board applications by integrating a light-diffusing pressure-sensitive adhesive layer, matte layer, and louver layer, ensuring high symmetry and preventing display image reflection on windshields.
Implementation Method 1
the light-diffusing pressure-sensitive adhesive layer contains a pressure-sensitive adhesive and light-diffusible fine particles dispersed in the pressure-sensitive adhesive
Implementation Method 2
The pressure-sensitive adhesive has a refractive index of from 1.47 to 1.60, and the light-diffusible fine particles each have a refractive index lower than the refractive index of the pressure-sensitive adhesive
Implementation Method 3
the louver layer includes a louver film that has light-transmitting portions each having a trapezoidal section arrayed along the louver film plane, and light-absorbing portions each having a trapezoidal section arrayed between the light-transmitting portions, wherein a bias angle of the louver layer is 6 degrees
Data Source
Figure 1~2
AI summary
There is provided an optical laminate that can achieve a liquid crystal display apparatus in which the occurrence of moire is suppressed, and which is excellent in brightness and viewing angle characteristic. An optical laminate of the present invention includes in the stated order: a polarizer; a light-diffusing pressure-sensitive adhesive layer; a matte layer; and a louver layer. The louver layer has light-transmitting portions each having a trapezoidal section arrayed along a film plane, and light-absorbing portions each having a trapezoidal section arrayed between the light-transmitting portions. A haze value H of the light-diffusing pressure-sensitive adhesive layer and a bias angle B of the louver layer satisfy relationships represented by the following expressions (1) to (3) : 2≤B≤6 20≤H≤60 B×H≥40 where the bias angle means a tilt angle of each of the trapezoidal sections with respect to a normal direction.