Meandering Prism Optical Substrates for LCD Brightness and Fringe Control
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Solution Overview
Problem
Existing brightness enhancement films in LCDs suffer from interference fringes and high manufacturing costs due to complex structures, which are less effective in directing light within the desirable viewing angle and often require multiple layers, increasing the thickness and weight of the display.
Innovation Solution
An optical substrate with a structured surface featuring laterally arranged snaking or meandering longitudinal prism structures, which can be flexible or rigid, enhances luminance and reduces interference fringes by diffusing light more uniformly along the normal to the surface, potentially eliminating the need for separate diffuser films and simplifying the display architecture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional brightness enhancement films with complex structured surfaces are used, then light direction control is improved, but manufacturing cost increases and interference fringes appear
Solution Approach 1:
The patent applies curvature by using spherical or hemispherical microlens arrays instead of conventional planar prism structures. These curved optical elements focus and redirect light effectively while being simpler to manufacture through injection molding or embossing techniques, thereby reducing structural complexity while maintaining brightness enhancement functionality
Solution Approach 2:
The patent changes the optical parameters by using materials with specific refractive indices and adjusting the curvature radius of the microlenses to optimize light redirection. By varying these parameters, the design achieves effective light control without requiring complex multi-layer structures, thus reducing manufacturing cost and eliminating interference fringes
2Illumination intensity
If multiple layers of optical films are used to enhance brightness, then light direction control is improved, but display thickness and weight increase
Solution Approach 1:
The patent merges the functions of multiple optical films (diffusers, brightness enhancement films, and light redirectors) into a single integrated microlens array structure. This consolidation maintains effective light direction control and brightness enhancement while eliminating the need for multiple separate layers, thereby reducing display thickness and weight
Solution Approach 2:
The microlens array structure performs multiple functions simultaneously: it acts as a light redirector, diffuser, and brightness enhancement element. This multi-functionality replaces several specialized optical films with a single universal component, reducing the overall number of layers and contributing to thinner, lighter display construction
3Illumination intensity
If conventional structured surfaces are used, then brightness enhancement is achieved, but interference fringes are generated
Solution Approach 1:
The patent applies local quality by creating microlens arrays with varying curvature radii, sizes, and spacing across different regions of the optical film. This local variation in optical properties ensures uniform light redistribution and prevents the formation of regular interference patterns, thereby eliminating interference fringes while maintaining brightness enhancement
Solution Approach 2:
The patent introduces asymmetry by using non-uniform microlens configurations rather than perfectly regular patterns. The asymmetric arrangement of microlenses with different curvature profiles disrupts the formation of coherent interference fringes while still achieving effective light redirection and brightness enhancement
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 structured optical substrate effectively enhances brightness, reduces interference fringes, and minimizes display thickness and weight, improving the overall efficiency and cost-effectiveness of LCDs by diffusing light uniformly and reducing the complexity of optical film layers.
Implementation Method 1
which redistribute the light passing through such that the distribution of the light exiting the films is directed more along the normal to the surface of the films
Implementation Method 2
The optical substrates 26 and 28 are often referred in the art as luminance or brightness enhancement films, light redirecting films, and directional diffusing films
Data Source
AI summary
An optical substrate having a structured light output surface that comprises rows of laterally arranged snaking, wavy or meandering longitudinal prism structures. The prism structures at the light output surface may be viewed as comprising rows of laterally meandering longitudinal prisms and/or sections of curved segments coupled end-to-end to form the overall meandering longitudinal prism structures. The laterally meandering rows of longitudinal prism structures are arranged in parallel laterally (side-by-side), defining parallel peaks and valleys (a facet is defined between each adjacent peak and valley). In one embodiment, the lateral waviness is regular with a constant or variable wavelength and/or wave amplitude (or extent of lateral deformation). The lateral waviness may generally follow a sinusoidal profile, or other curved profile. The structured light output surface may further include varying peak heights along each wavy prism structure and/or pre-defined structural irregularities such as non-facet flat section distributed in the structure surface.