Planar Field Emission Light Source with ZnO Nanorods

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Solution Overview

Problem

Existing field emission light sources, such as those described in EP1709665 and EP1246263, face challenges in manufacturing complexity and cost, particularly in achieving uniformity and energy efficiency, and are not suitable for general-purpose lighting applications beyond short illumination cycles.

Innovation Solution

A two-dimensional planar manufacturing process for field emission light sources using nanostructured cathodes and anodes, with a spacer structure to control the distance between the cathode and anode, and the use of wavelength converting materials and reflective features to optimize light emission and energy efficiency, allowing for modular manufacturing and improved uniformity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a bulb-shaped three-dimensional field emission light source structure is used, then omnidirectional light emission is achieved, but manufacturing complexity and cost increase

Engineering Contradiction:
Improveomnidirectional light emissionVSAvoidmanufacturing complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The invention transitions from a three-dimensional bulb-shaped structure to a two-dimensional planar structure. The field emission cathode and anode are arranged in a planar configuration rather than a spherical geometry, simplifying manufacturing while maintaining light emission capabilities through modular assembly of multiple planar units

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Adaptability or versatility

If a bulb-shaped three-dimensional field emission light source structure is used, then omnidirectional light emission is achieved, but manufacturing uniformity deteriorates

Engineering Contradiction:
Improveomnidirectional light emissionVSAvoidlight uniformity
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The planar geometry provides a flat substrate that facilitates uniform deposition of functional layers and consistent electrical field distribution across the emission area, enabling better control over light uniformity compared to curved bulb surfaces

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The invention uses a modular planar design where the field emission device can be divided into separate functional layers (cathode, anode, spacer structures) that can be manufactured and assembled independently, allowing for better quality control and uniformity in each segment

Inventive Principle:
Principle #1Segmentation

3Illumination intensity

If traditional bulb structure manufacturing is used, then light emission is achieved, but manufacturing cost increases

Engineering Contradiction:
Improvelight emissionVSAvoidmanufacturing cost
Core Design Contradiction:
Illumination intensityVSEase of manufacture

Solution Approach 1:

The planar structure enables fabrication using standard semiconductor and thin-film deposition techniques on flat substrates, which are more cost-effective and scalable than glass bulb manufacturing processes, reducing overall production costs

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The planar field emission device can be integrated with other planar components and manufactured using universal thin-film deposition techniques applicable to multiple device types, enabling economies of scale and reduced manufacturing costs

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 solution enables cost-effective, efficient, and uniform light emission over a wide range, suitable for general-purpose lighting, with enhanced manufacturing efficiency and reduced complexity compared to traditional bulb structures.

Implementation Method 1

Field emission is a phenomenon which occurs when a very high electric field is applied to the surface of a conducting material. This field will give electrons enough energy such that the electrons are emitted (into vacuum) from the material.

Methodology Applied
Scientific EffectField emission: Electron Avalanche

Implementation Method 2

As the electrons strike the light emitting layer, typically comprising a light powder such as a phosphor material, the light powder will emit photons. This process is referred to as cathodoluminescence.

Methodology Applied
Scientific EffectCathodoluminescence: Cathodoluminescence

Data Source

PatentEP3511974B1Field emission light source
Publication Date: 2021.02.24 LIGHTLAB SWEDEN AB
  • EP3511974B1 patent drawingFigure 1~2a
  • EP3511974B1 patent drawingFigure 2b~3
  • EP3511974B1 patent drawingFigure 4a~4d

AI summary

The present invention relates to a field emission light source die configured to emit UV light and a method for forming such a field emission light source. The field emission light source comprises a field emission cathode (106) comprising a plurality of ZnO nanorods (104) formed on a wafer, an electrically conductive anode structure (108) comprising a wavelength converting material (118) arranged to cover at least a portion of the anode structure, and a circular or elliptical spacer structure (110) for forming an hermetically sealed and evacuated cavity (306) between the substrate of the field emission cathode and the anode structure.