Multilayer Optical Film with Embedded Diffuser for Backlight Uniformity
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Solution Overview
Problem
Current backlight systems for display systems, such as LCDs, face challenges in achieving efficient and uniform spatial, angular, and spectral illumination, with existing optical films often increasing the thickness of the backlight unit and not adequately addressing moire interference.
Innovation Solution
A multilayer optical construction with embedded diffuser films, featuring structured layers with specific refractive indices and surface features, and embedded diffusers with varying optical haze, is used to efficiently spread and recycle light, minimizing thickness while reducing moire interference and enhancing uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional optical films are used to spread light and improve uniformity, then light uniformity is improved, but the thickness of the backlight unit increases
Solution Approach 1:
The patent combines multiple optical functions (light diffusion, reflection, and directional control) into a single integrated optical film structure. The film integrates a diffuser layer with structured reflective surfaces, merging what would traditionally require separate components into one thin element, thereby improving light uniformity without increasing overall thickness
Solution Approach 2:
The optical film uses composite material structures combining diffuse scattering materials with structured reflective surfaces. This composite approach allows the film to simultaneously perform multiple optical functions (diffusion and directional control) in a single thin layer, resolving the contradiction between uniformity improvement and thickness control
2Illumination intensity
If multiple optical films are stacked to achieve desired optical effects, then optical performance is improved, but device complexity increases
Solution Approach 1:
The patent merges multiple optical films into a single integrated film that performs diffusion, reflection, and angular control functions simultaneously. This consolidation reduces the number of separate optical components from multiple stacked films to one multi-functional film, thereby reducing device complexity while maintaining optical performance
Solution Approach 2:
The integrated optical film is designed to perform multiple functions: light diffusion through the diffuser layer, reflection through structured surfaces, and angular control through specific geometric features. This multi-functionality eliminates the need for separate specialized films, reducing overall system complexity
3Use of energy by moving object
If conventional optical films are used, then light transmission is achieved, but moire interference is not adequately reduced
Solution Approach 1:
The patent applies local quality variations through structured surfaces with specific geometric features (prisms, pyramids, or other shapes) that create localized light redirection patterns. These structured regions work together with the diffuser layer to break up regular interference patterns, reducing moire effects while maintaining overall light transmission
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 provides improved light uniformity and energy distribution across the display, increasing average effective transmission by up to 2% compared to conventional constructions, while maintaining a thin format and reducing visible moire interference.
Implementation Method 1
At least a first embedded optical diffuser is embedded within the optical construction between, and spaced apart from, the first and second structured major surfaces. The first embedded optical diffuser has an optical haze of greater than about 5% for at least one visible wavelength
Data Source
AI summary
An integral multilayer optical construction includes opposing first and second structured major surfaces having two-dimensional arrays of respective first and second structures. An optical diffuser is embedded within the optical construction between the first and second structured major surfaces. The optical diffuser has an optical haze of greater than about 5% for at least one visible wavelength in a visible wavelength range extending from about 420 nm to 680 nm. When the optical construction is disposed on a light source with one of the first and second structured major surfaces facing the light source, light emitted by the light source is transmitted by the optical construction with a cross-section of an angular luminous distribution of the transmitted light in at least one first plane that includes a normal to the optical construction, including first and second intensity peaks at respective first and second angles on opposite sides of the normal.