Micro-faceted Foils for Tunable Daylight Lighting

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Solution Overview

Problem

Existing artificial skylight solutions have low optical efficiency, often below 50%, due to light-absorbing optical elements and lack of independent control over blue sky and white light intensity, and are typically bulky, making them impractical for integration into existing structures.

Innovation Solution

A lighting unit utilizing two foil micro-facetted designs with different colored LEDs (white and blue) to redistribute light, creating a uniform appearance by mixing and redistributing light over a redirection window, allowing independent control of beam shape and spectral distribution, resulting in improved optical efficiency and a more compact design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If light-absorbing optical elements are used to create artificial skylight, then the blue sky effect can be achieved, but the optical efficiency drops below 50%

Engineering Contradiction:

Improveblue sky effectVSAvoidoptical efficiency

Core Design Contradiction:

Illumination intensityVSLoss of energy

Solution Approach 1:

The patent converts the harmful light absorption into beneficial light redirection. Instead of absorbing light to create the blue sky effect, the invention uses micro-facetted foils to reflect and redirect light from LED sources, achieving the desired angular distribution while maintaining high optical efficiency above 50%

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent changes the optical parameters by using multiple LED colors (white and blue) with different beam angles, and employs micro-facetted foil structures with specific geometries to achieve the desired light distribution. This allows independent control of the blue sky effect and white light intensity without relying on light-absorbing materials

Inventive Principle:

Principle #35Parameter changes

2Ease of operation

If two separate LED systems with different optics are used to control blue sky and white light independently, then independent control is achieved, but the system becomes spotty and requires a thick diffuser

Engineering Contradiction:

Improveindependent control of blue sky and white lightVSAvoidsystem thickness

Core Design Contradiction:

Ease of operationVSLength of stationary object

Solution Approach 1:

The patent merges multiple LED types (white and blue) into a single integrated system with micro-facetted foils, eliminating the need for separate optical systems. This combination achieves independent control of blue sky and white light while maintaining a compact, uniform appearance without requiring thick diffusers

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The micro-facetted foils act as intermediaries that redistribute light from multiple LED sources uniformly across the exit aperture. This intermediary structure eliminates the spotty appearance that would result from using separate LED systems while maintaining independent control capabilities

Inventive Principle:

Principle #24Intermediary (Mediator)

3Illumination intensity

If a diffuser is placed at considerable distance from the LED array to achieve uniform appearance, then uniformity is improved, but the system becomes impractically thick and bulky

Engineering Contradiction:

Improveuniform appearanceVSAvoidsystem thickness

Core Design Contradiction:

Illumination intensityVSLength of stationary object

Solution Approach 1:

The patent transitions from using distance (one dimension) to achieve uniformity to using micro-facetted foil structures (adding spatial complexity in another dimension). The foils with intricate micro-geometries redistribute light uniformly across the exit aperture while maintaining a compact form factor, eliminating the need for thick diffusers

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 significantly enhances optical efficiency, allows for independent tuning of blue skylight and white light effects, and maintains a slim profile, providing a convincing daylight experience while being suitable for various indoor environments.

Implementation Method 1

two foils with micro-facetted structures to mix and redistribute the light at the exit window

Methodology Applied

Scientific EffectReflection: Reflection

Implementation Method 2

first redistribution optical elements... configured to redirect the first light source light... second redirection optical elements... configured to shape at least part of the received second light source light

Methodology Applied

Scientific EffectRefraction: Refraction

Data Source

PatentUS10072820B2Tunable daylight experience using micro faceted foils

Publication Date: 2018.09.11 SIGNIFY HOLDING BV

AI summary

The invention provides a lighting unit (1) for providing daylight experience for a human. The lighting unit (1) comprises: a first light source (10) and a second light source (20) configured to provide light source light (11,21) having different spectral distributions, a light transmissive first light redistribution window (100) configured downstream of the first light source (10) and a light transmissive second light redistribution window (200) configured downstream of the second light source (20), a light transmissive redirection window (300) configured downstream of the first light redistribution window (100) and the second light redistribution window (200), and optionally a diffuser window (400) configured downstream of the light transmissive redirection window (400).