Surveillance Device LED Beam Angle Optimization
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Solution Overview
Problem
Current infrared illuminators for surveillance devices face issues of light wastage due to wide beam angles, internal light reflection causing glare, and vulnerability when LEDs are exposed, leading to inefficiencies and increased costs.
Innovation Solution
The use of a combination of diffuser and Fresnel lens to spread and redirect narrow beams of light from LEDs, increasing the beam angle from 20 degrees to 120 degrees, reducing internal reflection, and enhancing lighting efficiency while maintaining structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If light emitting diodes with wide beam angle are used, then lighting coverage is improved, but light is lost internally and reflected into the lens causing flare
Solution Approach 1:
A reflective element is introduced as an intermediary component between the light emitting diode and the lens. This reflective element intercepts light that would otherwise be lost internally or reflected into the lens, and redirects it usefully, thereby eliminating flare while maintaining wide lighting coverage.
2Loss of energy
If light emitting diodes are disposed close to the exterior of the infrared illuminators, then light wastage is reduced, but additional costs are required
Solution Approach 1:
The reflective element is designed to utilize light that would naturally travel along the housing walls, turning what would be wasted light into useful illumination. This self-service approach redirects existing light paths without requiring additional light sources or complex external positioning, thereby reducing light wastage without incurring additional manufacturing costs.
3Reliability
If light emitting diodes are enclosed, then device security is improved, but light is lost internally and reflected into the lens
Solution Approach 1:
The reflective element acts as an intermediary that resolves the conflict between enclosure and light efficiency. It is positioned within the enclosed housing to maintain security, while simultaneously capturing and redirecting light that would otherwise be lost, thus preserving both device security and light efficiency.
4Loss of energy
If light emitting diodes are not enclosed, then light loss is reduced, but illuminators are vulnerable to tampering and environmental damage
Solution Approach 1:
The reflective element enables the use of enclosed housings by efficiently capturing and redirecting light within the enclosure. This makes enclosure practical and desirable, as it simultaneously provides both light efficiency and protection against tampering and environmental damage.
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 optimizes lighting efficiency by minimizing light loss and glare, providing comprehensive illumination while maintaining device security and reducing costs.
Implementation Method 1
The narrow beams of light emitted from the light emitting diodes pass through a diffuser disposed between the light emitting diodes and the Fresnel lens
Implementation Method 2
The beams of light then pass through a Fresnel lens disposed behind the diffuser and configured to further increase the beam angles of the beams of light and to direct each beam of light off of a center axis
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
A surveillance device (100) includes a circuit card assembly (104) disposed in a housing (102) and a plurality of light emitting diodes (108; 202) disposed on the circuit card assembly (104), each of the plurality of light emitting diodes (108; 202) configured to emit a narrow beam of light. The surveillance device (100) further includes a diffuser (114; 204) disposed in the housing (102), the diffuser (114; 204) configured to spread the narrow beam of light and a Fresnel lens (112; 206) disposed in the housing (102), the Fresnel lens (112; 206) configured to spread and redirect light emitted from the diffuser (114; 204).