Antiglare Layer Surface Roughness for Display Contrast
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Solution Overview
Problem
Conventional optical layered bodies for image display devices face challenges in achieving both antiglare properties and good black color reproducibility, particularly in high-definition panels, as they often result in whitening or deteriorated contrast due to surface roughness and internal scattering effects, while methods to control reflectance through light interference face difficulties in production and can produce interference colors.
Innovation Solution
A method for producing an optical layered body with a light-transmitting substrate and an antiglare layer having specific surface roughness parameters, including a mean spacing of profile irregularities (Sm) between 50 μm and 100 μm, a mean inclination angle (θa) of 0.1° to 1.0°, and a mean roughness (Rz) of 0.2 μm to 1.0 μm, which is formed using a composition containing a resin and fine particles with a refractive index difference of 0.2 or less, and optionally includes a low refractive index layer and an antistatic agent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a fine surface roughness is formed to respond to high definition panel resolution, then antiglare property is improved, but contrast deteriorates and whitening occurs
Solution Approach 1:
The invention changes the surface roughness parameters from conventional fine roughness to a specific range (Ra: 0.3-1.5 μm, Ry: 1.5-6.0 μm) that balances antiglare performance with contrast maintenance. This parameter optimization prevents excessive light scattering while maintaining resolution response, thereby resolving the contradiction between antiglare property and contrast.
Solution Approach 2:
The invention uses a composite antiglare layer comprising a resin matrix combined with specific inorganic particles (silica, alumina, or titania) having controlled size distribution (0.5-5 μm average diameter). This composite structure provides both the necessary surface roughness for antiglare effect and controlled light scattering properties that maintain contrast, preventing the whitening problem.
2Ease of manufacture
If scattering particles with refractive index difference are added to create internal scattering effect, then scintillation is prevented, but surface whitening increases and contrast deteriorates
Solution Approach 1:
The invention optimizes the particle size parameters (average diameter 0.5-5 μm, with specific distribution ratios) and surface roughness parameters (Ra: 0.3-1.5 μm, Ry: 1.5-6.0 μm) to achieve controlled internal scattering that prevents scintillation while maintaining adequate contrast. The controlled particle size prevents excessive whitening.
Solution Approach 2:
The invention creates local quality variation through a layered particle distribution where larger particles (1-5 μm) are concentrated in the lower portion for scintillation prevention, while smaller particles (0.5-2 μm) are in the upper portion for surface roughness control. This spatial distribution optimizes both scintillation prevention and contrast maintenance.
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 effectively controls optical properties to achieve antiglare performance, prevent scintillation, and ensure high gloss blackness and black color reproducibility, reducing diffuse reflection and maintaining adequate contrast, even in bright environments.
Implementation Method 1
an antiglare layer having a surface roughness is formed on the surface of a transparent substrate... can prevent the reduction in visibility due to reflection of external light or reflection of images by scattering external light through a surface roughness of the surface
Implementation Method 2
an optical layered body for antireflection is provided on the outermost surfaces thereof... inhibits the reflection of images or decreases a reflectance by virtue of scattering and interference of light
Data Source
AI summary
A method for producing an optical layered body which can attain properties such as an antiglare property, scintillation prevention and black color reproducibility such as gloss blackness simultaneously, and a production apparatus of the optical body are provided. The method includes forming an antiglare layer having a surface roughness on the light-transmitting substrate, wherein with respect to the surface roughness, when denoting a mean spacing of profile irregularities of the surface of the optical layered body by Sm, a mean inclination angle of profile irregularities by θa, and mean roughness of the surface roughness by Rz, Sm is 50 μm or more and less than 100 μm, θa is 0.1° or more and 1.0° or less, and Rz is more than 0.2 μm and 1.0 μm or less.