Artificial Window Lighting Device with Directional Blue Reflectance

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing artificial skylights are not suitable for use as artificial windows on walls, as they create an unnatural blue sky effect when applied to vertical surfaces, failing to replicate the authentic appearance of a real window.

Innovation Solution

A lighting device in the form of an artificial window, featuring an enclosure with perpendicular axes and partitioning elements that create sub-spaces with specific reflective properties. The device emits light with a high blue reflectance in an upward direction and low blue reflectance in a downward direction, mimicking a bright blue sky above and a more natural appearance below.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If artificial skylights are used to provide a blue sky effect, then the appearance of a bright blue sky is achieved, but the effect becomes unnatural when applied to vertical walls

Engineering Contradiction:
Improveblue sky effectVSAvoidunnatural appearance
Core Design Contradiction:
Illumination intensityVSObject-generated harmful factors

Solution Approach 1:

The patent applies different reflective properties to different parts of the lighting device. The first reflective inner surface is designed with high blue reflectance (>20%) to create a blue sky effect for upward viewing, while the second reflective inner surface has low blue reflectance (<20%) to provide a natural appearance for downward viewing. This local differentiation of optical properties resolves the contradiction between achieving a blue sky effect and avoiding unnatural appearance.

Inventive Principle:
Principle #3Local quality

2Illumination intensity

If a non-directional light source is used inside a cavity, then a blue sky effect is created through scattered light, but the direct light creates a well-delimited beam that does not match real window appearance

Engineering Contradiction:
Improveblue sky effectVSAvoidlight beam distribution
Core Design Contradiction:
Illumination intensityVSShape

Solution Approach 1:

The patent divides the enclosure into multiple sub-spaces separated by partitioning elements, with each sub-space containing its own light source. Each sub-space has first and second reflective inner surfaces with different blue reflectance properties. This segmentation allows independent control of light paths and reflective properties in different regions, enabling the device to simultaneously provide blue sky effect and natural appearance without the well-delimited beam problem of non-directional sources.

Inventive Principle:
Principle #1Segmentation

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 lighting device effectively creates a realistic and authentic impression of a real window by simulating a bright blue sky above and a more natural, earth-like appearance below, overcoming the unnatural effects of previous technologies.

Implementation Method 1

the first reflective inner surface has a first blue reflectance and the second reflective inner surface has a second blue reflectance, wherein the first blue reflectance is more than 20 % and the second blue reflectance is less than 20 %

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

Each sub-space further comprises a light source arranged to emit light towards the front surface with a light output. The light output comprises light beams in a blue wavelength range of 400-490 nm and in a non-blue wavelength range of 490-700 nm.

Methodology Applied
Scientific EffectLight Emitting Diode: Light Emitting Diode

Data Source

PatentEP4211393B1Lighting device
Publication Date: 2025.04.16 SIGNIFY HOLDING BV
  • EP4211393B1 patent drawingFigure 1
  • EP4211393B1 patent drawingFigure 2a~2b
  • EP4211393B1 patent drawingFigure 2c

AI summary

A lighting device, comprising an enclosure (120) comprising a plurality of partitioning elements (130a-f) to form within the enclosure a plurality of sub-spaces (140a-e) each comprising first and second reflective inner surfaces (170, 180), wherein each sub-space further comprises a light source (110) arranged to emit light with a light output, the light output comprising light beams in a blue wavelength range of 400-490 nm and in a non-blue wavelength range of 490-700 nm, a first part of the light output being incident on the first reflective inner surface of the sub-space and a second part of the light output being incident on the second reflective inner surface of the sub-space, wherein, for light within the blue wavelength range, the first reflective inner surface has a first blue reflectance (310) of &gt; 20 %, and the second reflective inner surface has a second blue reflectance (320) of &lt; 20 %.