Ring Pointer Illumination Using Light Guide and Reflective Elements
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Solution Overview
Problem
Existing illuminated gauge systems face challenges in providing uniform illumination for pointers moving around the outer circumference of gauges, especially with expensive color LEDs and varying light intensity, which increases material and assembly costs.
Innovation Solution
A ring pointer assembly utilizing a light guide with a minimal number of LEDs, where light is transmitted through a guide with reflective surfaces to ensure consistent illumination across the pointer's movement, reducing the need for multiple LEDs and maintaining uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If multiple LEDs are placed about the circumference of the gauge to illuminate a pointer driven about the outer scale, then the pointer illumination is achieved, but the material cost increases due to expensive color LEDs (white and green)
Solution Approach 1:
A light guide is introduced as an intermediary component between the LEDs and the pointer. The light guide receives light from a minimal number of LEDs (two or more) and distributes it uniformly along its circumferential path where the pointer moves. This mediator allows few LEDs to illuminate the entire pointer trajectory effectively, reducing the total number of LEDs needed while maintaining consistent illumination intensity.
2Illumination intensity
If multiple LEDs are disposed about the outer circumference of the gauge to provide pointer illumination, then illumination coverage is improved, but the uniformity of illumination varies much more than desired
Solution Approach 1:
The light guide acts as a mediating structure that receives light from discrete LED sources and transforms it into a continuous, uniform illumination along the pointer's path. The light guide's geometry and optical properties ensure even light distribution, eliminating the non-uniformity that would result from direct LED-to-pointer illumination.
Solution Approach 2:
The light guide is designed with specific local optical properties (reflective surfaces, refractive indices, geometric configurations) that optimize light distribution at different locations along its path. This local optimization ensures that each segment of the light guide provides appropriate illumination intensity, achieving overall uniformity across the entire pointer trajectory.
3Illumination intensity
If a plurality of LEDs are placed about the circumference of the gauge, then pointer illumination is achieved, but the assembly cost increases
Solution Approach 1:
The light guide serves as a cost-reducing intermediary that allows the system to use fewer LEDs. Since LEDs (especially white and green colors) are expensive, reducing their quantity from multiple circumferential LEDs to just two or more strategically placed LEDs significantly lowers material and assembly costs while the light guide maintains the necessary illumination function.
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 solution achieves uniform illumination of the pointer with a reduced number of LEDs, minimizing material and assembly costs while allowing for independent movement of pointers around the gauge's perimeter, ensuring consistent light intensity and aesthetic appeal.
Implementation Method 1
at least two LEDs that transmit light through a light guide to a pointer assembly
Implementation Method 2
Light transmitted through the light guide from the LED is reflected by a plurality of reflective surfaces within the light guide transversely into the pointer
Data Source
AI summary
An illuminated pointer assembly for a gauge scale having an outer periphery includes a pointer that moves about a periphery of the gauge scale and is illuminated by a light guide. The light guide is disposed on a plane below the pointer and the gauge scale. The light guide includes at least two LEDs that are disposed adjacent first and second ends of the light guide. The light guide also includes a plurality of reflective elements. The plurality of reflective elements is disposed in sets that are orientated with regard to each of the LEDs. The reflective elements provide for the transmission and direction of light within the light guide into the guide body portion of the pointer.