Optical Diffusion Device with Asymmetric Microlens Array
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Solution Overview
Problem
Existing optical diffusion devices in backlight modules fail to effectively distribute light uniformly, leading to dim and dark regions, and their designs often compromise the compactness and efficiency of the module, with micro-particle coating processes offering limited uniformity and high yield, and microstructure designs exhibiting low diffusion rates and random diffusion directions.
Innovation Solution
An optical diffusion device with a plate containing optical microstructures having a longer and shorter axis, where the direction of the longer axis is approximately parallel to the light source direction, and the shorter axis direction is approximately perpendicular, enhancing light diffusion and increasing luminance by optimizing the curvature of these axes to improve light distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the gap between light sources and diffuser is extended to admit more light streams, then diffusion uniformity is improved, but the backlight module becomes thicker
Solution Approach 1:
The patent transitions from a conventional flat diffuser design to a three-dimensional microlens array structure with specific curvature radii. By introducing vertical dimensionality through convex lens surfaces with different curvature radii (first curvature radius in horizontal direction, second curvature radius in vertical direction), the device achieves improved light diffusion uniformity without increasing the horizontal gap distance, thus resolving the contradiction between diffusion quality and module thickness.
Solution Approach 2:
The patent optimizes specific geometric parameters of the microlens array, including the curvature radii (first and second curvature radii), lens pitch, and height of the convex surfaces. By precisely controlling these parameters, the device achieves effective light diffusion with a compact structure, improving diffusion uniformity while maintaining a thin profile and avoiding the need to increase the gap between light sources and diffuser.
2Ease of manufacture
If micro-particles are coated on substrate surface to achieve diffusion, then manufacturing process is simple, but diffusion uniformity and yield are limited
Solution Approach 1:
The patent divides the diffuser into an array of discrete microlenses with specific geometric structures. Each microlens acts as an independent optical element with controlled curvature radii and pitch, providing precise and uniform light diffusion. This segmented approach replaces the random distribution of micro-particles with a structured array, significantly improving diffusion uniformity and manufacturing yield while maintaining ease of manufacture through standardized fabrication processes.
3Ease of manufacture
If frosted glass structure is used for light diffusion, then manufacturing is easier, but diffusion rate is low and direction is random
Solution Approach 1:
The patent employs a microlens array with convex spherical or aspherical surfaces having specific curvature radii instead of a frosted glass structure. The curved lens surfaces provide controlled refraction and focusing of light, achieving high diffusion rates with directional control. This curved surface approach maintains manufacturing simplicity while dramatically improving both diffusion rate and directional control compared to random frosted glass structures.
4Productivity
If continuous arc lens array with greater than semicircle is used, then optical diffusion is maximized, but uniform diffusion of light streams is not achieved
Solution Approach 1:
The patent employs asymmetric microlens design where the first curvature radius (horizontal direction) differs from the second curvature radius (vertical direction). This asymmetric curvature configuration, combined with specific pitch ratios between horizontal and vertical directions, corrects the non-uniform light distribution caused by symmetric continuous arc designs. The asymmetric structure optimizes light diffusion uniformity across different viewing angles while maintaining high optical diffusion efficiency.
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 better light distribution and increased luminance by enhancing the diffusion effect through the shorter axis, reducing dim and dark regions, and correcting moiré effects in 3D displays, while maintaining a compact design.
Implementation Method 1
Multiple optical microstructures 22, each having a longer axis 221 and a shorter axis 222... permit streams of light emitted from those light sources 3 to be uniformly diffused through the optical diffusion device 2
Implementation Method 2
the diffusion effect in the direction of the longer axis 221 is way below that in the direction of the shorter axis 222... to increase the light among multiple light sources 3
Data Source
AI summary
An optical diffusion device applied in a backlight module includes a plate. Multiple light sources are disposed on one side of the plate. Multiple optical microstructures provided with a longer axis and a shorter axis are disposed on the plate. The longer axis of each optical microstructure is approximately arranged in parallel with a direction extending from the light source, or, in other words, the shorter axis is arranged approximately crossing the direction extending from the light source. A diffusion effect is provided to each light source through the shorter axis of the optical microstructure to increase optical radiant energy among the light sources and to eliminate the dim and dark regions among the light sources for increasing general luminance of the backlight module.