Traffic Signal Optic for Uniform LED Light Distribution
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Solution Overview
Problem
Conventional LED traffic signals lack uniform light intensity, leading to a visually displeasing appearance due to discernible LEDs and potential shadows, especially when LEDs burn out or are not matched in intensity and color.
Innovation Solution
The use of an optic with light pipes that redirect light rays emitted by LEDs to provide a uniform distribution, reducing the number of LEDs required while maintaining a consistent light appearance, and incorporating a housing and cover with a seal to prevent environmental contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If multiple LEDs are used in an array to replicate incandescent lamp light output, then the light appearance is improved, but the uniformity of light surface is worsened
Solution Approach 1:
An optic element (lens or diffuser) is introduced as an intermediary between the LEDs and the external environment. This optic redistributes the light from multiple LEDs uniformly across the signal face, hiding the individual LED positions and creating a uniform appearance similar to traditional incandescent lamps.
Solution Approach 2:
Multiple LEDs are combined within a single housing and optically integrated through a common optic element. The optic merges the light output from individual LEDs into a unified, uniform light surface, presenting them as a single homogeneous light source rather than discrete points.
2Ease of manufacture
If fewer LEDs are used to reduce cost, then the manufacturing cost is reduced, but the uniformity of light surface is worsened
Solution Approach 1:
The optic element serves as a light redistributing mediator that allows fewer LEDs to achieve uniform illumination. By optically redistributing light from a smaller number of LEDs across the entire signal face, the system maintains uniform appearance while reducing component count and manufacturing cost.
3Device complexity
If LEDs are not closely matched in intensity and color, then the manufacturing complexity is reduced, but the uniformity of light surface is worsened
Solution Approach 1:
The optic element acts as a neutralizing intermediary that equalizes the output from LEDs with varying intensity and color characteristics. Through light redistribution and scattering, the optic masks the differences between individual LEDs, producing a uniform overall appearance without requiring precise LED matching during 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 solution achieves a uniform light distribution, reducing the visibility of individual LEDs and potential shadows, enhancing the aesthetic appeal and reliability of LED traffic signals while minimizing maintenance costs.
Implementation Method 1
An optic resides adjacent to the at least one LED and re-directs light rays emitted by the LED to provide a uniform distribution of light through the cover
Data Source
AI summary
A LED signal (2) having has an element that facilitates providing a uniform distribution of light is illustrated. The LED signal (2) includes a housing (4) and a cover (6) operatively attached the housing (4). At least one LED (12) resides on at least one circuit board (14), which is affixed to the housing (4) opposite the cover (6). An optic (18) resides adjacent to the at least one LED (12) and redirects light rays emitted by the LED (12) to provide a uniform distribution of light through the cover (6).