Double-pear-shaped Reflector for Uniform Facade Lighting

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Solution Overview

Problem

Existing facade lighting systems with point light sources face challenges in achieving uniform illumination and minimizing glare, especially when radiators are close to the facade and need to illuminate large sections, often resulting in uneven illumination and increased glare due to the rotational symmetry of light cones or linear wedges.

Innovation Solution

The use of double-pear-shaped or twin-shell-shaped reflectors with a convexly curved transition ridge, allowing for oblique, pyramid-like light distribution to evenly illuminate rectangular sections without tilting radiators, and featuring a constriction that decreases in depth to ensure efficient light capture and distribution without shadows, achieving high uniformity and low glare.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If spotlights are positioned close to the facade to illuminate large sections, then the lighting arrangement becomes compact and less disruptive, but uniformity of illumination deteriorates and glare increases

Engineering Contradiction:
Improvecompactness of lighting arrangementVSAvoiduniformity of facade illumination
Core Design Contradiction:
Volume of moving objectVSIllumination intensity

Solution Approach 1:

The patent applies asymmetry by using non-rotationally-symmetric reflector shapes (such as cylindrical sectors with different curvature radii in different directions, or freeform surfaces with varying slopes) to generate asymmetric light cones. This asymmetric reflector geometry redirects light rays to achieve uniform illumination distribution on the facade surface, transforming the naturally asymmetric illumination pattern from close-positioned spotlights into a uniform distribution without requiring large distances from the facade.

Inventive Principle:
Principle #4Asymmetry

2Volume of moving object

If spotlights are positioned close to the facade to illuminate large sections, then the lighting arrangement becomes compact and less disruptive, but glare increases

Engineering Contradiction:
Improvecompactness of lighting arrangementVSAvoidglare from spotlights
Core Design Contradiction:
Volume of moving objectVSObject-generated harmful factors

Solution Approach 1:

The asymmetric reflector design redirects light rays in controlled asymmetric patterns, directing the asymmetric light cones away from observer positions near the facade. The reflector geometry is specifically designed to channel light toward the facade surface while minimizing direct light exposure to observers, thereby reducing glare while maintaining compact positioning.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent employs local quality by designing reflectors with spatially varying properties - different curvature radii in different directional zones, or freeform surfaces with location-dependent slope angles. These localized variations in reflector geometry control the redirection of light rays from specific source regions to specific target regions on the facade, optimizing both uniformity and glare reduction in different spatial zones simultaneously.

Inventive Principle:
Principle #3Local quality

3Illumination intensity

If differently angled spotlights are used to achieve uniform illumination, then coverage is improved, but glare increases in many places

Engineering Contradiction:
Improveuniformity of facade illuminationVSAvoidglare from differently angled spotlights
Core Design Contradiction:
Illumination intensityVSObject-generated harmful factors

Solution Approach 1:

Instead of using multiple spotlights at different angles, the patent employs a single asymmetric reflector that inherently generates an asymmetric light cone. This single asymmetric light source replaces multiple asymmetric sources, achieving uniform illumination through the reflector's geometry while minimizing the number of light sources that could potentially cause glare from different directions.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent merges the functions of multiple differently angled spotlights into a single asymmetric reflector system. The asymmetric reflector integrates the light-redirection capabilities that would otherwise require multiple separate light sources, consolidating them into one unit that provides both uniform illumination and controlled glare reduction through its unified asymmetric geometry.

Inventive Principle:
Principle #5Merging (Combining)

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 solution provides high-intensity, uniform facade lighting with minimal glare, allowing for compact installation and efficient light usage, with light sources positioned above the illuminated area without obstructing the view, and achieving lighting efficiencies of over 80%.

Implementation Method 1

the reflector is designed as a whole to capture the light of a point light source radiating into a hemisphere in a substantially complete manner

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP3199869B1Illumination device
Publication Date: 2020.06.24 BARTENBACH HLDG
  • EP3199869B1 patent drawingFigure 1
  • EP3199869B1 patent drawingFigure 2
  • EP3199869B1 patent drawingFigure 3~4

AI summary

The present invention relates to a lighting device with at least one series of spotlights, a spotlight for such a lighting device for illuminating a surface area, and a reflector for such a spotlight, wherein the reflector, for substantially completely capturing the light of a point light source radiating into a hemisphere, is designed as a whole to be approximately hemispherical and is formed by at least two halves of the shell. According to the invention, the halves of the shell together form an approximately double-pear-shaped hemisphere, which has an approximately slit-like constriction formed by the transition region of the two halves of the shell, wherein the constriction extends over the reflector shell and has a depth that decreases from one side of the reflector to the opposite side of the reflector.