Asymmetric Prism Microstructures for Mini-LED Backlight Uniformity
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Solution Overview
Problem
Conventional mini-LED backlight modules suffer from uneven brightness and low light utilization due to multiple reflections in the surface light source, which is exacerbated by the isosceles right triangle cross-section of conventional prism sheets, leading to reduced light acquisition and efficiency.
Innovation Solution
A backlight module design featuring light mixing microstructures and concentrating microstructures, including lens and prism microstructures, are disposed on an optical film layer above the light emitting elements to uniformly mix light and reduce reflections, with the microstructures being bilaterally symmetric to the optical axis of the elements and having refractive indices optimized for improved light collection and emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a conventional prism sheet with isosceles right triangle cross-section is used, then the structure is simple and easy to manufacture, but light acquisition is poor and multiple reflections occur causing low brightness
Solution Approach 1:
The patent applies asymmetry by changing the prism sheet cross-section from an isosceles right triangle to an asymmetric triangle where the acute angles are different (first acute angle ≠ second acute angle). This asymmetric design optimizes light acquisition angles and reduces multiple reflections, thereby improving brightness and light utilization efficiency.
Solution Approach 2:
The patent applies parameter changes by modifying the geometric parameters of the prism sheet, specifically the acute angles of the triangular cross-section. By optimizing these angular parameters, the light mixing effect is improved while reducing harmful multiple reflections, thus enhancing overall light emission efficiency.
2Illumination intensity
If diffusion sheet and prism sheet are added above Mini-LEDs, then light mixing effect is improved, but light utilization rate decreases due to multiple reflections
Solution Approach 1:
The asymmetric prism design redirects light paths more efficiently, reducing the number of reflections needed for light mixing. This decreases energy loss from multiple reflections while still achieving uniform light distribution across the display surface.
Solution Approach 2:
By optimizing the angular parameters of the asymmetric prism, the patent achieves better light mixing uniformity with fewer reflections, thereby improving light utilization rate while maintaining uniformity.
3Loss of energy
If conventional edge light backlight module is used, then light utilization rate is high, but light-mixing distance is limited causing uneven brightness
Solution Approach 1:
The patent segments the backlight system into Mini-LED arrays with asymmetric prisms at specific positions, allowing localized light mixing optimization. This segmentation enables better control over light distribution while maintaining overall light utilization 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 design enhances light mixing uniformity and increases the proportion of light energy output, improving the light emitting efficiency of the surface light source by 20%-30% and reducing light absorption and reflection losses.
Implementation Method 1
lens microstructure and a prism microstructure having a light collecting effect on an upper surface of an optical film layer of a light emitting element of a surface light source
Implementation Method 2
the effect of multiple reflections inside the surface light source is reduced during concentrating process
Data Source
AI summary
A backlight module is provided. The backlight module includes a substrate; a plurality of light emitting elements disposed on the substrate; an optical film disposed on the plurality of light emitting elements; a plurality of light mixing microstructures disposed on the optical film, positions of the light mixing microstructures corresponding to positions of the plurality of light emitting elements; and a plurality of concentrating microstructures correspondingly disposed on the plurality of light mixing microstructures, wherein positions of the plurality of concentrating microstructures correspond to the positions of the plurality of light emitting elements. A liquid crystal display (LCD) device including the backlight module is also provided.