Optical Lens Microstructures for Thin Backlight Uniformity
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Solution Overview
Problem
Conventional direct type backlight modules face challenges in achieving lightness, thinness, and uniform illumination due to limitations in light-mixing distance and manufacturing complexity of secondary lenses, particularly with refracting and reflecting type lenses.
Innovation Solution
An optical lens design featuring a main body with a recessed light-incident surface, a reflecting surface, and a light-emitting surface with microstructures having different normal line directions, allowing for adjustable light propagation paths and controlled light-emitting angles, which simplifies manufacturing and enhances illumination uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the light-mixing distance of the secondary lens is decreased to achieve lightness and thinness, then the thickness of the backlight module is reduced, but the illumination uniformity deteriorates
Solution Approach 1:
The secondary lens is divided into multiple independent lenses, each with a specific light-emitting angle. By arranging multiple lenses with different light-emitting angles (e.g., 60°, 90°, 120°) in different regions, the patent achieves both thinness (by eliminating the need for long light-mixing distance) and uniform illumination (by combining light from multiple angles)
Solution Approach 2:
Different regions of the backlight module use lenses with different light-emitting angles tailored to local requirements. The patent applies lenses with varying light-emitting angles in different areas to optimize both thickness and illumination uniformity locally, rather than using a single lens type throughout
2Illumination intensity
If the number of light-emitting diodes is increased to improve illumination uniformity, then the illumination uniformity is improved, but the device complexity and manufacturing cost increase
Solution Approach 1:
The patent uses optical lenses that perform multiple functions: they control light direction, mix light from different LEDs, and achieve uniform illumination. This multi-functionality allows fewer LEDs to be used while still achieving good illumination uniformity, as the lenses compensate for the reduced number of light sources
3Adaptability or versatility
If the light-incident surface and light-emitting surface of the reflecting type lens are designed as complicated curved surfaces to increase light-emitting angle, then the light-emitting angle is increased, but the manufacturing precision deteriorates and cost increases
Solution Approach 1:
Instead of using a single complex reflecting lens, the patent segments the light control function into multiple simpler lenses with different light-emitting angles. This segmentation replaces complicated curved surfaces with multiple simpler optical elements that are easier to manufacture with high precision
Solution Approach 2:
The patent inverts the conventional approach by using refracting lenses instead of reflecting lenses. This inversion allows achieving large light-emitting angles without requiring complicated curved surfaces, as the refracting lenses can be manufactured with simpler geometries while maintaining or improving precision
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 optical lens design reduces the number of lenses needed, decreases overall thickness, and improves illumination uniformity while simplifying the manufacturing process by using microstructures with different slopes and curvatures to control light paths.
Implementation Method 1
The reflecting surface is recessed into the top portion of the main body and opposite to the light-incident surface. After entering the main body of the optical lens from the light-incident surface, the light beam provided by the light source is reflected by the reflecting surface
Implementation Method 2
The light-emitting surface connects the top portion and the bottom portion, in which the light-emitting surface has plural microstructures. Each of the microstructures has a normal line, and directions of the normal lines are different from each other
Data Source
AI summary
An optical lens, a backlight module and a display device are provided. The optical lens includes a main body, a light-incident surface, a reflecting surface and a light-emitting surface. The main body has a top portion and a bottom portion. The light-incident surface is recessed into the bottom portion of the main body. The reflecting surface is recessed into the top portion of the main body and opposite to the light-incident surface. The light-emitting surface connects the top portion and the bottom portion, in which the light-emitting surface has plural microstructures. Each of the microstructures has a normal line, and directions of the normal lines are different from each other.