Light Guide Plate Microlens Array Uniformity
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Solution Overview
Problem
Conventional light guide plates for plane light source units face inefficiencies in light uniformity and manufacturing due to limitations in pattern processing and the need for additional diffuser components, which affect light emission and production costs.
Innovation Solution
A light guide plate with segmented optical patterns of varying size and density, where microlenses have equal heights, improving light uniformity and efficiency by adjusting the arrangement of microlens arrays on the surface, eliminating the need for a diffuser plate and simplifying manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If white dot patterns are used on the light guide plate, then light scattering and transmission are achieved, but light loss occurs and fill factor is limited
Solution Approach 1:
The patent changes the geometric parameters of the optical patterns from printed white dot patterns to raised microlens structures with specific height (sag) values. By controlling the sag parameter of the microlenses, the system achieves improved light uniformity while maintaining higher light efficiency compared to traditional white dot patterns.
Solution Approach 2:
The patent divides the light guide plate surface into multiple unit pattern regions with different optical pattern densities and sag values. Each region is optimized locally to control light scattering and transmission characteristics, achieving overall light uniformity while minimizing light loss through strategic placement of microlens structures.
2Illumination intensity
If a diffuser plate or diffuser sheet is stacked on the light guide plate to hide white dot patterns, then light uniformity is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent merges the light scattering function and the light guiding function into a single integrated light guide plate structure. The microlens patterns are directly formed on the light guide plate surface, eliminating the need for separate diffuser plates or sheets, thereby reducing structural complexity while maintaining light uniformity.
Solution Approach 2:
The light guide plate with microlens patterns serves multiple functions simultaneously: it guides light from the LED source, scatters light to achieve uniform distribution, and eliminates the need for additional diffuser components. This multi-functional design simplifies the overall device structure and reduces manufacturing complexity.
3Manufacturing precision
If laser machining is used to manufacture the light guide plate pattern, then processing is achieved, but pattern processing time is long and fine patterns are limited
Solution Approach 1:
The patent replaces the mechanical laser machining process with a molding process to manufacture the light guide plate patterns. The microlens patterns are formed by injecting molten material into a mold with the desired pattern geometry, enabling faster production and the ability to create fine patterns that would be difficult to achieve through laser machining.
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
Enhances light uniformity and efficiency while reducing manufacturing complexity and costs by optimizing microlens array patterns on the light guide plate, allowing for improved light emission without additional diffuser components.
Implementation Method 1
Light emitted from a light source 20 is propagated while being totally reflected through a light guide plate 30
Implementation Method 2
A critical angle for total reflection is determined by refractive indexes of a medium and an air layer, based on Snell's law
Data Source
AI summary
A light guide plate and a plane light source unit are provided. The light guide plate for a plane light source unit includes a plurality of unit pattern regions each having a plurality of optical patterns on surfaces thereof, wherein one or more unit pattern regions have different sag values (height:lens size) of the optical patterns constituting the unit pattern regions. Unit pattern regions are implemented with segmented optical patterns, which are equal in height, from the outside of the light guide plate to the central part thereof, by adjusting the density and size of microlenses, thereby improving the light uniformity and light efficiency and improving the efficiency of manufacturing processes.