Microlens Array Diffuser Plate for Uniform Light Distribution
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Solution Overview
Problem
Existing diffuser plates with microlens arrays in a rectangular grid structure face challenges in achieving uniform light distribution due to interference and diffraction, leading to uneven intensity distribution, despite variations in microlens arrangement and shape.
Innovation Solution
A diffuser plate with a microlens array featuring irregularly varied grid intervals and curvature radii in both the X and Y directions, along with off-centered vertex positions, creating a three-dimensional surface structure that controls light phase overlap and reduces diffraction, ensuring uniform light distribution in two orthogonal directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If microlenses are arranged in a regular rectangular grid with identical shapes, then manufacturing is simple, but light distribution uniformity deteriorates due to interference and diffraction
Solution Approach 1:
The patent applies local quality by making each microlens have different surface shapes and different grid intervals from its neighbors. Specifically, microlenses are designed with varying curvature radii (Rx, Ry) and aperture sizes (Dx, Dy) based on their local position in the array, creating spatially varying optical properties that eliminate periodic interference patterns while maintaining manufacturability through systematic design rules.
Solution Approach 2:
The patent implements asymmetry by intentionally designing microlenses without rotational symmetry. The surface shapes are made asymmetric through different curvature radii in orthogonal directions (Rx ≠ Ry) and different aperture dimensions (Dx ≠ Dy), which breaks the periodic symmetry that causes diffraction and interference, thereby achieving uniform light distribution.
2Illumination intensity
If microlens shapes are varied to reduce interference, then light distribution uniformity improves, but manufacturing complexity increases
Solution Approach 1:
The patent applies parameter changes by systematically varying key microlens parameters (curvature radii Rx, Ry and aperture sizes Dx, Dy) across the array. These parameters are adjusted according to specific design rules that create the desired optical effect while maintaining a manageable level of complexity through structured variation rather than complete randomness.
3Manufacturing precision
If grid intervals are made uniform, then manufacturing precision is easier to control, but diffraction effects increase causing luminance unevenness
Solution Approach 1:
The patent applies local quality to grid intervals by making each microlens position have different spacing from its neighbors. The grid interval in the x-direction (Wx) and y-direction (Wy) are varied locally across the array, eliminating the periodic structure that causes diffraction while still allowing for controlled manufacturing through systematic design rules.
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 significantly reduces unevenness in luminance distribution and improves light uniformity in both directions, achieving a top hat diffusion property with a diffusion angle of less than or equal to 20°, effectively controlling anisotropy and intensity distribution.
Implementation Method 1
A type of diffuser plate utilizes light refraction resulting from the surface shape of the diffuser plate to diffuse incident light at a desired diffusion angle.
Implementation Method 2
as a result of interference of a wavefront of light from each of microlenses, a diffraction wave due to a periodic structure of a microlens array occurs, which causes unevenness in intensity distribution of diffused light
Implementation Method 3
as a result of interference of a wavefront of light from each of microlenses, a diffraction wave due to a periodic structure of a microlens array occurs
Data Source
AI summary
To reduce unevenness in a luminance distribution in two directions of microlenses disposed in a form of a rectangular grid to improve uniformity of light distribution. Provided is a diffuser plate of a microlens array type including a base material, and a microlens array composed of a plurality of microlenses disposed on an X-Y plane on at least one surface of the base material using a rectangular grid as a reference, in which grid intervals Wx in an X direction of the microlenses disposed in the X direction of the rectangular grid are different from each other, grid intervals Wy in a Y direction of the microlenses disposed in the Y direction of the rectangular grid are different from each other, and surface shapes of the plurality of microlenses are different from each other.