Horticulture Lighting Device Using Red LED and Wavelength Converter

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Solution Overview

Problem

Existing horticulture lighting technologies, such as fluorescent lamps and phosphor converted LEDs, are inefficient and have drawbacks like high energy consumption, short lifespan, and limited availability of far-red LEDs, which hinder optimal plant growth and bio-rhythm stimulation.

Innovation Solution

A horticulture lighting device utilizing direct red LEDs with a wavelength converting member to efficiently produce far-red light, reducing Stokes loss and requiring fewer components, thereby enhancing efficiency and ease of assembly, while mimicking daylight to influence phytochrome responses in plants.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If phosphor converted LEDs are used to generate far-red light from blue light, then far-red light can be produced, but the efficiency is low due to large Stokes shift

Engineering Contradiction:

Improveefficiency of far-red light generationVSAvoidStokes loss

Core Design Contradiction:

Use of energy by moving objectVSLoss of energy

Solution Approach 1:

The patent changes the excitation wavelength parameter from blue light (450-480 nm) to red light (620-680 nm), which reduces the Stokes shift to 40-120 nm and increases conversion efficiency to 75-85%

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

Instead of converting blue light to far-red light (the conventional approach), the patent inverts the approach by converting red light to far-red light, which minimizes energy loss due to smaller Stokes shift

Inventive Principle:

Principle #13The other way round (Inversion)

2Use of energy by moving object

If direct far-red LEDs are used, then far-red light can be generated, but they are relatively inefficient and not widely available

Engineering Contradiction:

Improveavailability and efficiency of far-red light sourceVSAvoidefficiency and availability

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The patent uses red light as an intermediary to generate far-red light through wavelength conversion, avoiding the need for direct far-red LEDs while achieving high efficiency and wide availability

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent substitutes the mechanical/electrical system of direct far-red LED fabrication with an optical conversion system using red LEDs and wavelength converting members, which is more reliable and widely available

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Illumination intensity

If fluorescent lamps are used for plant illumination, then broad spectrum light can be provided, but they have limited efficiency, contain hazardous materials, and have short lifetime

Engineering Contradiction:

Improvespectral coverageVSAvoidenergy efficiency

Core Design Contradiction:

Illumination intensityVSUse of energy by moving object

Solution Approach 1:

The patent applies local quality by providing targeted red and far-red light wavelengths that match plant photopigment absorption spectra, rather than broad spectrum illumination, thereby improving energy efficiency while maintaining biological effectiveness

Inventive Principle:

Principle #3Local quality

4Adaptability or versatility

If multiple wavelength converting members are used to generate red and far-red light, then both spectral ranges can be covered, but the device complexity and assembly difficulty increase

Engineering Contradiction:

Improvespectral range coverageVSAvoidnumber of components

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent makes the red LED serve multiple functions: it provides direct red light for plant illumination and simultaneously acts as an excitation source for the wavelength converting member to generate far-red light, thereby reducing component count while maintaining spectral coverage

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 device provides a highly efficient combination of red and far-red light emission, improving plant growth and bio-rhythm stimulation by optimizing the red to far-red light ratio, reducing energy consumption, and extending the lifespan of the lighting system.

Implementation Method 1

a solid state light source arranged to emit direct red light

Methodology Applied

Scientific EffectElectroluminescence: Electroluminescence

Implementation Method 2

a wavelength converting member arranged to receive at least part of the direct red light emitted from the solid state light source and to convert the received direct red light to far-red light

Methodology Applied

Scientific EffectPhotoluminescence: Photoluminescence

Data Source

PatentUS10299441B2Horticulture lighting device and a method to stimulate plant growth and bio-rhythm of a plant

Publication Date: 2019.05.28 SIGNIFY HOLDING BV

AI summary

The present invention relates to a lighting device (100) to stimulate plant growth and bio-rhythm of a plant. The lighting device (100) comprising a solid state light source (102) arranged to emit direct red light having a wavelength of 600 to 680 nm, preferably 640 to 680 nm, and a wavelength converting member (106) arranged to receive at least part of said direct red light emitted from said solid state light source (102) and to convert said received direct red light to far-red light having a maximum emission wavelength of 700 to 760 nm, preferably 720 to 760 nm.