LCD Protective Film Roughness for Scratch Prevention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Liquid crystal display devices face challenges in achieving both improved brightness and satisfactory display performance, particularly due to light leaks and display unevenness caused by scratches and surface interactions between the backlight unit and the liquid crystal panel.
Innovation Solution
The configuration of the liquid crystal display device includes a liquid crystal panel with a polarizing plate and a backlight unit, where the outermost surface of the panel facing the backlight unit is a protective film, and the outermost surface of the backlight unit facing the panel is a diffusion member, with specific surface roughness and hardness conditions to prevent scratches and maintain display quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a diffusion member is positioned closest to the liquid crystal panel side in the backlight unit, then brightness on the display surface is improved, but light leaks and display unevenness occur due to scratches and surface interactions
Solution Approach 1:
The invention applies different surface roughness characteristics to different components: the protective film is made rougher (Ra1 > Ra2) to prevent scratches, while the diffusion member maintains a smoother surface for optimal light diffusion. This localized differentiation of surface properties resolves the contradiction between brightness improvement and display performance reliability.
Solution Approach 2:
The invention introduces a protective film with specific surface roughness characteristics as a cushioning layer between the diffusion member and the liquid crystal panel. This protective film prevents direct contact and potential scratches before they can occur, thereby maintaining display performance while allowing the diffusion member to remain in the optimal position for brightness enhancement.
2Reliability
If the protective film surface is made rougher to prevent scratches, then display performance is maintained, but light diffusion efficiency may be reduced
Solution Approach 1:
The invention carefully balances surface roughness by making the protective film slightly rougher than the diffusion member (Ra1 > Ra2) but not excessively so. This localized quality differentiation ensures scratch prevention while maintaining adequate light diffusion efficiency through the diffusion member's smoother surface.
Solution Approach 2:
The invention optimizes the surface roughness parameters of both the protective film and diffusion member within specific ranges. By controlling Ra1 and Ra2 to maintain a specific relationship (Ra1 > Ra2) rather than using extreme values, the invention achieves both scratch resistance and acceptable light diffusion performance through parameter optimization.
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
This configuration enhances brightness and suppresses light leaks and display unevenness, such as Newton rings, by ensuring the protective film surface is rougher than the diffusion member surface, preventing scratches and maintaining optimal display performance.
Implementation Method 1
a member (a diffusion member) having light diffusibility which is called a diffusion plate, a diffusion sheet
Implementation Method 2
an arithmetic mean roughness measured on an outermost surface of the liquid crystal panel on the backlight unit side is set as Ra1... an arithmetic mean roughness measured on an outermost surface of the backlight unit on the liquid crystal panel side is set as Ra2
Data Source
AI summary
A liquid crystal display device has a liquid crystal panel including a liquid crystal cell and a polarizing plate; and a backlight unit including a light source. An outermost surface of the liquid crystal panel on the backlight unit side is a surface of a protective film included in the polarizing plate, an outermost surface of the backlight unit on the liquid crystal panel side is a surface of a diffusion member, and where an arithmetic mean roughness measured on an outermost surface of the liquid crystal panel on the backlight unit side is Ra1, a pencil hardness is P1, an arithmetic mean roughness measured on an outermost surface of the backlight unit on the liquid crystal panel side is Ra2, and a pencil hardness is P2, Expression 1: 33 nm<Ra1<135 nm, Expression 2: Ra2<15 nm, and Expression 3: P1<P2 are satisfied.