Pyramid Phosphor Device with Asymmetric Reflection Layers

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Solution Overview

Problem

Conventional light source apparatuses using phosphor particles in resinous binders face issues with degradation under excitation light, leading to reduced luminance due to low thermal conductivity and temperature quenching, and existing inorganic binders do not have a suitable structure for efficient light emission.

Innovation Solution

A phosphor device comprising phosphor particles shaped like a pyramid or cone with inclined faces and reflection layers, where the second face has a reflection-preventing layer to allow efficient light emission, using a transparent inorganic binder like Al2O3 to enhance thermal conductivity and light output.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a resinous binder is used to disperse phosphor particles, then the phosphor device can be manufactured with ease, but the thermal conductivity is low causing temperature rise and luminance decrease

Engineering Contradiction:
Improveease of manufactureVSAvoidphosphor temperature
Core Design Contradiction:
Ease of manufactureVSTemperature

Solution Approach 1:

The patent changes the material parameter of the binder from resinous (low thermal conductivity) to inorganic transparent material (high thermal conductivity), thereby improving heat dissipation while maintaining manufacturability through sintering processes

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite structure combining inorganic transparent binder material with phosphor particles, achieving both high thermal conductivity for heat dissipation and optical transparency for light emission

Inventive Principle:
Principle #40Composite materials

2Illumination intensity

If high intensity excitation light is applied to the phosphor, then the luminance output is improved, but the resinous binder degrades and phosphor temperature rises

Engineering Contradiction:
Improveluminance outputVSAvoidbinder stability
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The patent changes the thermal and optical parameters of the binder material to inorganic transparent materials that can withstand high intensity excitation light without degradation, enabling sustained high luminance output

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the degradable resinous binder with a more stable inorganic binder material that does not degrade under high intensity excitation, ensuring long-term reliability

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Device complexity

If phosphor particles are arranged in a conventional structure, then the device complexity is reduced, but self-absorption occurs and light emission efficiency decreases

Engineering Contradiction:
Improvedevice complexityVSAvoidlight emission efficiency
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The patent employs asymmetric pyramid-shaped cavities with specific inclination angles (45-60 degrees) to control light propagation paths, preventing self-absorption while maintaining relatively simple device structure

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent introduces geometric dimensioning with pyramid-shaped cavities having specific inclination angles, using spatial arrangement to direct light output and prevent self-absorption without significantly increasing device complexity

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 phosphor device achieves high-efficiency light emission by reflecting and guiding light beams through the structure, preventing self-absorption and maintaining emission intensity, and can be integrated into illumination and projector apparatuses for improved performance.

Implementation Method 1

The first face and the inclined faces include reflection layers that reflect light beams emitted from phosphor particles with a wavelength in a visible-light region

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

The second face includes a reflection preventing layer that allows passage of the light beams emitted from the phosphor particles

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 3

phosphor particles, which emit a light beam having a wavelength different from that of excitation light coming from a light source and applied to the phosphor

Methodology Applied
Scientific EffectPhotoluminescence: Photoluminescence

Data Source

PatentEP2574982B1Phosphor device, illumination apparatus and projector apparatus
Publication Date: 2019.06.19 CASIO COMPUTER CO LTD
  • EP2574982B1 patent drawingFigure 1A~1B
  • EP2574982B1 patent drawingFigure 2
  • EP2574982B1 patent drawingFigure 3

AI summary

A phosphor device (1) containing phosphor particles (2) for emitting light beams, shaped like a pyramid or cone and including first and second faces (4-5,4-6) opposed to each other and having different areas. The first face and the inclined faces have reflection layers (5) configured to reflect light beams emitted from the phosphor particles. The second face, including a reflection preventing film (6), is an input face for excitation light and also an output face for the light beams.