Illuminating Lens Total Reflection Radial Light Distribution
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Solution Overview
Problem
Conventional illuminating lenses for light emitting diodes (LEDs) in liquid-crystal display backlights have limitations in widening the range of light transmission directions, leading to uneven illuminance and the need for a large number of LEDs, which increases costs.
Innovation Solution
An illuminating lens design that utilizes total reflection to distribute light radially, featuring a light exit surface with a transmissive region and a total reflection region, allowing for a wider range of light transmission directions and stabilizing illuminance with a lower cost configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a conventional lens with only refraction is used, then the structure is simple, but the range of light transmission directions cannot be widened sufficiently
Solution Approach 1:
The light exit surface is segmented into multiple functional regions: a transmissive region for direct light transmission, a total reflection region for redirecting light at specific angles, and intermediate regions. This segmentation allows different portions of the lens to perform different optical functions, thereby widening the overall range of light transmission directions without significantly increasing structural complexity
Solution Approach 2:
Different regions of the light exit surface are assigned different optical properties: the transmissive region has high transmission, the total reflection region has high reflectivity, and intermediate regions have gradient properties. This local differentiation of optical quality enables the lens to control light distribution across a wider angular range while maintaining a relatively simple overall structure
2Illumination intensity
If the number of light emitting diodes is increased to achieve uniform brightness, then the illuminance uniformity is improved, but the cost increases
Solution Approach 1:
The patent extracts and utilizes total internal reflection phenomenon within the lens structure itself to redistribute light from fewer LEDs. By incorporating a total reflection region at the light exit surface, the lens can redirect light that would otherwise be lost or concentrated in specific directions, thereby achieving more uniform illuminance distribution across the backlight surface without increasing the number of LED sources
Solution Approach 2:
The patent changes the optical parameters of the lens by introducing regions with different refractive indices and surface geometries. The total reflection region is designed with specific curvature and refractive index characteristics that enable light redirection at controlled angles. This parameter modification allows a single LED (or fewer LEDs) to illuminate a larger area more uniformly, reducing the total number of LEDs required
3Manufacturing precision
If the difference in height between concave and convex portions is reduced, then the manufacturing precision is improved, but the range of light transmission directions is limited
Solution Approach 1:
The patent introduces intermediate regions between the transmissive region and the total reflection region. These intermediate regions act as optical mediators with gradient refractive indices and controlled surface geometries that smoothly transition light between the two extreme regions. This intermediary structure enables effective light redistribution across a wide angular range while maintaining manageable height differences that are feasible for manufacturing
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 lens effectively widens the range of light transmission directions, reducing the number of LEDs required and stabilizing illuminance on the surface, while maintaining a cost-effective design.
Implementation Method 1
the total reflection region totally reflects light that has been emitted from the starting point at a relatively large angle with respect to the optical axis and then reached the first light exit surface
Implementation Method 2
the transmissive region transmits light that has been emitted from the starting point at a relatively small angle with respect to the optical axis and then reached the first light exit surface
Data Source
AI summary
A light exit surface of an illuminating lens has a first light exit surface and a second light exit surface. The first light exit surface is recessed toward a point on the optical axis, and the second light exit surface extends outwardly from the periphery of the first light exit surface. The first light exit surface has a transmissive region and a total reflection region. When the position of a light source on the optical axis is defined as a starting point, the transmissive region transmits light that has been emitted from the starting point at a relatively small angle with respect to the optical axis, and the total reflection region totally reflects light that has been emitted from the starting point at a relatively large angle with respect to the optical axis. A bottom surface that surrounds a light entrance surface and faces oppositely to the light exit surface is provided with a projecting portion or a recessed portion for reflecting light that has been emitted from the light source, totally reflected repeatedly at the light exit surface, and then reached the bottom surface.