LED Warning Light Trough Reflector and Lens Design
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Solution Overview
Problem
Existing warning light systems for emergency vehicles face challenges in achieving a 360° visual warning pattern with sufficient intensity and aesthetic appeal, as high-output LED lamps produce limited luminous flux with a wide viewing angle, requiring efficient redirection of light to meet federal and state standards while maintaining a low-profile design.
Innovation Solution
The optical system employs a combination of LUXEON Rebel LED lamps, a trough reflector with parabolic surfaces, and a lens to redirect light into a vertically collimated wide-angle beam, expanding the illuminated surface area while minimizing the height of the warning light, ensuring maximum intensity and angular spread within a horizontal plane.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If high-output LED lamps are used to produce light, then light output per unit energy is improved, but the total luminous flux is insufficient and viewing angle is too wide
Solution Approach 1:
Multiple LED lamps are combined in an array configuration to accumulate their individual luminous flux outputs. The patent describes arranging multiple LED lamps in a linear array where each lamp contributes to the total light output, achieving sufficient illumination intensity for warning applications while maintaining the energy efficiency of individual LED lamps.
Solution Approach 2:
Optical elements including reflectors and lenses are introduced as intermediaries to redirect and focus the wide-angle light from LED lamps into a more directional beam. The reflector redirects light that would otherwise escape at wide angles, and the lens focuses the accumulated light from multiple LEDs into a concentrated beam pattern suitable for warning applications.
2Illumination intensity
If multiple LED lamps are accumulated in a compact array, then total luminous flux is improved, but device height increases
Solution Approach 1:
The optical elements are designed to manipulate light in the angular dimension rather than requiring increased physical height. The reflector and lens redirect light rays at different angles to achieve beam concentration and directionality, allowing the system to achieve sufficient luminous flux without proportionally increasing the vertical dimension of the device.
3Measurement precision
If light is redirected into a directed beam, then illumination accuracy is improved, but light scattering losses increase
Solution Approach 1:
The reflector is designed to capture and redirect light that would otherwise be scattered uselessly at wide angles. By positioning the reflector to intercept these scattered rays and redirecting them into the beam path, the system converts what would be energy losses into useful illumination, simultaneously improving beam directionality and reducing overall light scattering losses.
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
This configuration enhances the angular spread and intensity of the warning illumination pattern, meeting aesthetic and functional requirements by efficiently redirecting light from multiple LED lamps into a low-profile, aerodynamically pleasing design that complies with standards for emergency vehicle warning lights.
Implementation Method 1
a reflector with a pair of reflecting surfaces laterally spaced from and parallel to the linear array of LED lamps. The reflecting surfaces have a lower portion defined by intersecting circular parabolic surfaces
Implementation Method 2
A lens extends the length of and is positioned axially above the linear array of LED lamps and between the reflecting surfaces. The lens includes a central region intersected by the optical axes of the LED lamps
Data Source
AI summary
An optical system for an LED array includes a trough reflector in combination with an elongated lens. The reflector and lens include distinct regions dedicated to particular zones of light emanating from the LED array. The reflector includes lower, upper and end portions, each configured to redirect a particular zone of wide angle light from the LED array into a pre-determined warning light pattern. The lens includes central, side and end regions, each configured to redirect a particular zone of narrow angle light from the LED array into the pre-determined warning light pattern. The shape of the trough reflector and lens, as well as the relationship between the lens and reflector, are selected to provide an optical system with expanded illuminated surface area and a low profile.