Irregular Micro-Lens Array Sheet for Backlight Units
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Solution Overview
Problem
Liquid crystal display devices suffer from moiré patterns when using micro-lens array sheets with periodic micro-lens arrangements, which can reduce brightness and image quality, especially at increased viewing angles.
Innovation Solution
A micro-lens array sheet with irregularly arranged conic lenses, where the standard deviation in distances between adjacent micro-lens centers is 2% to 20% of the average pitch, and 50% or less of the basic array units are regular-triangle units, to minimize periodicity and maintain brightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If micro lenses are periodically arranged on the MLA sheet, then light condensing function is improved, but moiré patterns occur due to geometric interference
Solution Approach 1:
The patent applies asymmetry by changing the periodic arrangement of micro lenses to a non-periodic random arrangement. This eliminates the geometric interference that causes moiré patterns while preserving the light condensing function through statistical optical properties of the random distribution.
Solution Approach 2:
The patent changes the arrangement parameter from periodic to non-periodic random distribution. By controlling the density and spatial distribution statistics rather than fixed periodic positions, the patent maintains light condensing effectiveness while eliminating moiré pattern generation.
2Object-generated harmful factors
If micro lenses are irregularly arranged to reduce moiré patterns, then moiré patterns are reduced, but brightness may be remarkably reduced
Solution Approach 1:
The patent changes from periodic to non-periodic random arrangement while controlling density parameters to maintain brightness. The statistical properties of the random distribution preserve the overall light condensing power while eliminating the periodic interference patterns.
Solution Approach 2:
The patent maintains appropriate local density of micro lenses in the random arrangement to ensure sufficient light condensing at each region, preventing brightness reduction while achieving moiré pattern elimination through the overall non-periodic structure.
3Illumination intensity
If hemispheric micro-lens array sheets are used to improve brightness, then brightness is improved, but viewing angles decrease when increasing viewing angles
Solution Approach 1:
The patent uses conic lens surfaces with optimized curvature profiles to achieve both high brightness and wide viewing angles. The specific conic geometry allows light to be directed effectively while maintaining uniform optical properties across different viewing directions.
Solution Approach 2:
The patent optimizes the conic lens parameters (curvature, height, diameter) to balance brightness and viewing angle performance. By adjusting these geometric parameters, the patent achieves improved brightness without sacrificing viewing angle adaptability.
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 reduces moiré patterns while maintaining brightness and improving viewing angles, resulting in high-quality image display.
Implementation Method 1
The MLA sheet has a light condensing function as well as a light diffusing function
Implementation Method 2
a moiré pattern may occur due to geometric interference
Data Source
AI summary
The present invention relates to a microlens array sheet with enhanced optical performance, and a backlight unit having same, and more specifically, to a microlens array sheet and a backlight unit having same, the microlens array sheet comprising: a base portion; and a plurality of microlenses formed on one surface of the base portion, wherein the plurality of microlenses have an irregular array, and the standard deviation of the distance between the mid points of two microlenses adjacent to each other is, 2-20% of the average pitch(p) between microlenses adjacent from the mid point of a selected microlens after selecting one of the microlenses.