LED Switch Optic Assembly for Uniform Touch Indicator Illumination
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Solution Overview
Problem
Conventional LED indicators suffer from irregular illumination patterns due to their narrow light beam, leading to bright spots and dark areas, which can make the indicator less discernible and appear deactivated when it is not.
Innovation Solution
The development of an optic assembly for LEDs that includes a primary lens with a tapered section and a secondary lens with a central cavity, along with a conductive layer configuration on the printed circuit board, to ensure even illumination of indicia on a panel cover, enhancing the aesthetic and user interface experience.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a conventional LED with narrow light beam is used, then the LED structure is simple, but the illumination is irregular with bright spots and dark areas
Solution Approach 1:
The optic assembly is divided into two separate lenses: a primary lens positioned close to the LED and a secondary lens positioned farther away. The primary lens has a specific curvature designed to work with the LED's narrow beam, while the secondary lens provides additional diffusion. This segmentation allows each lens to be optimized for its specific function, achieving uniform illumination without requiring a single complex optical element.
Solution Approach 2:
The primary lens is positioned within or adjacent to the LED package structure, with the secondary lens surrounding or enclosing the primary lens arrangement. This nested configuration allows the optic assembly to be compact while maintaining the functional separation of the two lenses, achieving uniform illumination without excessive complexity or size.
2Area of stationary object
If the LED light beam is narrowed, then the LED structure is simpler, but the illumination area is reduced and becomes irregular
Solution Approach 1:
The illumination area expansion is achieved through two sequential lens elements rather than a single complex lens. The primary lens begins the diffusion process close to the LED, and the secondary lens further expands and evens out the light distribution. This segmented approach achieves wide uniform illumination without requiring an overly complex single-element optical system.
Solution Approach 2:
The optic assembly utilizes the spatial dimension by positioning lenses at different distances from the LED and from each other. The primary lens is close to the LED while the secondary lens is farther away, creating a multi-dimensional optical path that expands the illumination area uniformly without increasing lateral complexity of the assembly.
3Illumination intensity
If a single lens is used, then the device complexity is lower, but the illumination uniformity is poor with bright and dark spots
Solution Approach 1:
The single lens is replaced by two lenses with different curvatures and positions. The primary lens has a curvature optimized for close proximity to the LED, while the secondary lens has a different curvature optimized for diffusion at a greater distance. This segmentation of the optical function into two simpler elements achieves superior illumination uniformity compared to a single complex lens.
Solution Approach 2:
Each lens is designed with specific local optical properties: the primary lens has a curvature tailored for its position near the LED, and the secondary lens has a different curvature tailored for its position farther away. This local optimization of each lens's quality allows the combined system to achieve uniform illumination without requiring any single lens to be overly complex.
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 optic assembly provides uniform illumination over a wider area, ensuring the indicator is consistently visible and functional, while maintaining capacitive touch input functionality.
Implementation Method 1
The optic assembly provides uniform illumination over a wider area
Implementation Method 2
ensuring the indicator is consistently visible
Data Source
AI summary
An optic assembly for a light emitting diode mounted to a printed circuit board has a primary lens defined by a primary lens anterior surface and an opposed primary lens rear taper with a tip facing the light emitting diode. A secondary lens with a secondary lens anterior surface and an opposed secondary lens posterior surface faces the printed circuit board. The secondary lens defines a central cavity with the primary lens being disposed therein.