Facade Lighting Device Asymmetrical Free-Form Lens Uniform Illumination
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Solution Overview
Problem
Existing facade lighting systems with LED spotlights face challenges in achieving uniform illumination while minimizing glare, often resulting in unevenly lit areas and increased glare due to the use of rotationally symmetrical light cones and tilted spotlights.
Innovation Solution
The use of free-form lenses with asymmetrical light intensity distribution to illuminate rectangular sections of the facade, allowing multiple spotlights to complement each other and align parallelly, reducing the need for tilting and minimizing glare through longitudinal fade-out and pear-shaped isoluxes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If rotationally symmetrical light cones are used with tilted spotlights to illuminate the facade, then the illumination coverage is improved, but the uniformity of illumination deteriorates and glare increases
Solution Approach 1:
The patent applies asymmetry by using free-form lenses with asymmetrical light intensity distribution instead of rotationally symmetrical light cones. Each spotlight illuminates a rectangular section of the facade with non-uniform intensity distribution, where the intensity varies along the vertical direction to achieve uniform overall illumination when multiple spotlights are combined. This asymmetrical design allows the light intensity to be optimized for the specific rectangular illumination pattern required.
Solution Approach 2:
The patent implements local quality by creating different light intensity distributions in different regions of the illumination pattern. The free-form lens produces a light intensity distribution where the intensity varies locally along the vertical direction, with higher intensity at certain heights and lower intensity at others. This local variation in intensity distribution across the rectangular section allows each spotlight to contribute uniformly to the overall facade illumination when combined with adjacent spotlights.
2Illumination intensity
If tilted spotlights are used to achieve uniform illumination, then the illumination uniformity is improved, but glare from multiple observation points increases
Solution Approach 1:
The free-form lens creates an asymmetrical light intensity distribution that is optimized to reduce glare. The intensity distribution is designed such that the light is directed more strongly towards the facade surface and less strongly towards observation points at ground level. This asymmetrical distribution pattern, combined with parallel alignment of spotlights, minimizes the amount of light reaching observation points while maintaining uniform facade illumination.
Solution Approach 2:
The patent transitions from the conventional approach of using tilted spotlights (modifying orientation in one dimension) to using parallel spotlights with asymmetrical intensity distribution (modifying intensity distribution across another dimension). This dimensional shift allows glare control to be achieved through the intensity distribution pattern rather than through physical tilting, thereby reducing glare from multiple observation points while maintaining illumination uniformity.
3Illumination intensity
If multiple rows of facade spotlights aligned at different angles are arranged, then the uniformity of illumination is improved, but the device complexity increases
Solution Approach 1:
The patent simplifies the device complexity by using asymmetrical free-form lenses in parallel-aligned spotlights instead of arranging multiple rows of spotlights at different angles. The asymmetrical intensity distribution of each spotlight is designed to create uniform overall illumination when spotlights are arranged in a single row, eliminating the need for complex multi-row arrangements with different alignment angles.
Solution Approach 2:
The patent changes the parameter of light intensity distribution from the conventional uniform or symmetrical pattern to an optimized asymmetrical pattern. This parameter change in the light intensity distribution allows a single row of parallel spotlights to achieve the same uniform illumination effect that would otherwise require multiple rows of spotlights at different angles, thereby reducing device complexity.
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 approach achieves highly uniform facade lighting with a low glare effect, ensuring consistent illuminance over the facade section and minimizing glare from various observation points.
Implementation Method 1
each facade spotlight (6) has a free-form lens (8) with an asymmetry such that each facade spotlight (6) illuminates an approximately rectangular section (12) of the facade (2, 3)
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A building facade is illuminated externally by an array of light emitting diode spotlights groups (6) that stand clear of the building line and are arranged as pinpoints. Each group of LEDs is positioned under a lens unit throwing an asymmetric rectangular beam of light onto the building facade. The combined illumination results in a uniform appearance that does not dazzle the onlooker.