COB LED Lens Protrusion for Glare Reduction
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Solution Overview
Problem
Chip-on-board (COB) LED lighting systems face challenges in designing optical lenses to control illumination light patterns effectively, particularly in street lighting, as they tend to produce undesirable glare, backlight, and uplight, leading to light pollution and inefficiency.
Innovation Solution
A lens design with an index of refraction greater than 1, featuring an inner surface facing the light source and an outer surface of varying curvature, including a protrusion for total internal reflection, redirects light emitted from the COB LED into a confined beam pattern, reducing glare and unwanted illumination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a COB LED is used as a light source, then light intensity is improved, but light pollution (glare, backlight, uplight) increases
Solution Approach 1:
The optical element is divided into multiple functional zones: a first region with a first curvature radius, a second region with a second curvature radius, and a third region with a third curvature radius. Each region segments the light distribution in different angular ranges, directing light to specific areas while preventing glare, backlight, and uplight.
Solution Approach 2:
Different regions of the optical element have different curvature radii optimized for specific functions: the first region (0°-60°) has a first curvature radius for primary illumination, the second region (60°-90°) has a second curvature radius for controlling glare, and the third region (90°-180°) has a third curvature radius for minimizing uplight. This local optimization of optical properties addresses light pollution in different directions.
2Ease of operation
If optical lenses are designed for COB LEDs, then light pattern control is improved, but device complexity increases
Solution Approach 1:
The patent combines multiple optical functions into a single integrated optical element. The first, second, and third regions with different curvature radii are merged into one continuous surface, eliminating the need for separate lenses or optical components for different light distribution zones.
Solution Approach 2:
The optical element utilizes continuous curvature variation across different regions to achieve complex light control functions. By employing spherical or aspherical surface geometry with varying curvature radii, the design achieves precise light pattern control while maintaining a relatively simple single-element structure.
3Area of stationary object
If light is directed beyond 60°-70°, then illumination coverage is improved, but glare and backlight increase
Solution Approach 1:
The optical element is segmented into angular zones: the first region covers 0°-60° for primary illumination, the second region covers 60°-90° for controlling glare, and the third region covers 90°-180° for minimizing uplight. This segmentation allows light to be distributed across wide angles while controlling harmful illumination in each specific zone.
Solution Approach 2:
The second region (60°-90°) is specifically designed with a second curvature radius optimized to redirect light that would otherwise become glare, while the third region (90°-180°) uses a third curvature radius to redirect potential backlight and uplight. This local optimization allows extended coverage without proportionally increasing glare.
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 effectively limits light pollution by creating a clear, confined light distribution pattern that decreases intensity beyond the intended area of illumination, reducing glare and uplight, and optimizing light usage in street lighting applications.
Implementation Method 1
a peripheral edge portion of the outer surface is configured to redirect light emitted from the light source by total internal reflection
Implementation Method 2
an outer surface of varying curvature originating from a single point above the light source to an edge of the optical element
Data Source
AI summary
A cover for a light source for use in a lamp or luminaire. An outer surface of the cover, opposite the light source, comprises a rounded shape and includes a protrusion extending from the cover. The protrusion extends substantially in a light emission direction and is shaped the protrusion to direct light emitted from the light source in a desired direction.