LCD Backlight Module BEF Haze Optimization
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Solution Overview
Problem
Conventional liquid crystal display (LCD) backlight modules fail to achieve uniform high luminance, which is a requirement for meeting the TCO standards for high-quality LCDs, necessitating an improvement in optical performance.
Innovation Solution
The proposed solution involves an optimized backlight module with a brightness enhancement film (BEF) and diffusers, where the BEF enhancement coefficient is between 0.1 and 0.5, and the haze of the diffusers is within specific ranges, along with the use of Dual Brightness Enhancement Film (DBEF) and polarizers to enhance optical performance and meet TCO standards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional backlight modules are used, then manufacturing is simpler, but luminance uniformity and optical performance fail to meet TCO standards
Solution Approach 1:
The patent applies parameter changes by precisely controlling the enhancement coefficient of the brightness enhancement film (BEF) within 0.1 to 0.5 and the haze of the bottom diffuser within 0 to 50%. By optimizing these parameters, the backlight module achieves uniform luminance distribution and meets TCO standards while maintaining a relatively simple optical film structure.
Solution Approach 2:
The patent employs composite materials by combining the brightness enhancement film (BEF) with diffusers (bottom diffuser and top diffuser) in a layered optical film structure. This composite structure integrates the light-enhancing property of BEF with the light-scattering property of diffusers to achieve both high luminance and uniform distribution.
2Illumination intensity
If higher luminance is achieved, then display quality improves, but luminance uniformity deteriorates
Solution Approach 1:
The patent introduces the brightness enhancement film (BEF) as an intermediary component between the light source and the display panel. The BEF, with its controlled enhancement coefficient (0.1 to 0.5), acts as a mediator that enhances luminance while the diffusers (with controlled haze values) ensure uniform distribution, thus resolving the contradiction between high luminance and uniformity.
Solution Approach 2:
The patent applies local quality by using diffusers with specific haze values (bottom diffuser: 0 to 50%, top diffuser: 0 to 40%) at different positions in the optical path. The bottom diffuser provides initial light scattering while the top diffuser further uniformizes the light distribution, ensuring that each region contributes appropriately to overall luminance uniformity.
3Reliability
If conventional optical films are used, then device complexity is lower, but optical performance and TCO standard compliance are insufficient
Solution Approach 1:
The patent ensures TCO standard compliance by precisely controlling the enhancement coefficient of the BEF within 0.1 to 0.5 and the haze of the bottom diffuser within 0 to 50%. These parameter specifications guarantee that the optical performance meets TCO requirements while avoiding overly complex structural designs.
Solution Approach 2:
The patent uses a moderate enhancement coefficient (0.1 to 0.5) rather than excessive enhancement, and combines it with diffusers that provide just enough light scattering to achieve uniformity. This partial action approach meets TCO standards without introducing unnecessary complexity into the optical film structure.
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 achieves high luminance uniformity and optical performance, meeting TCO standards with maximum luminance exceeding 246 cd/m2, luminance ratio within specified limits, and maintaining high contrast, thereby ensuring superior quality LCDs.
Implementation Method 1
the enhancement coefficient of the brightness enhancement film (BEF) is defined to be the ratio of BEF vertical output intensity to BEF 40-degree output intensity
Implementation Method 2
the enhancement coefficient of the brightness enhancement film (BEF) is defined to be the ratio of BEF vertical output intensity to BEF 40-degree output intensity
Implementation Method 3
the haze of the bottom diffuser is within the range of from 0 to 50%
Implementation Method 4
the single transmittance of the polarizer is more than 42%, the parallel transmittance more than 35%, the cross transmittance less than 0.08%
Data Source
AI summary
A liquid crystal display module with backlight module providing an enhancement coefficient of the brightness enhancement film (BEF) within the range of 0.1 to 0.5. The backlight module is disposed behind the display panel and comprises a bottom diffuser, a brightness enhancement film, and a top diffuser disposed on the brightness enhancement film. A set of polarizers is disposed above and below the liquid crystal display panel. The backlight module meets TCO standards and has improved optical performance.