Concave Taper Light Source for Brightness Efficiency

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Solution Overview

Problem

The existing light source apparatus for projection type image display systems suffers from reduced brightness efficiency due to phosphor light being emitted in all directions and non-conversion exciting light not being utilized effectively, leading to a decrease in overall light usage efficiency.

Innovation Solution

The apparatus incorporates a metal member with a concave taper shape coated with phosphor, where the exciting light is input at one end and output phosphor light is converged to a specific angle, allowing all phosphor light to be captured, and non-conversion exciting light is re-directed for further conversion, using inorganic binders to prevent temperature-related issues and coating phosphor on multiple surfaces for enhanced conversion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If phosphor is coated on a flat surface, then the structure is simple, but phosphor light is emitted in all directions and cannot be fully captured

Engineering Contradiction:
Improvebrightness efficiencyVSAvoidstructure complexity
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The patent applies a concave taper shape to the phosphor coating surface, which curves the flat surface into a concave geometry. This curvature causes phosphor light to be emitted toward a specific angle rather than in all directions, enabling full capture by the condenser lens while maintaining structural simplicity.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Loss of energy

If exciting light is not re-directed, then the system is simple, but non-conversion exciting light is wasted

Engineering Contradiction:
Improvelight usage efficiencyVSAvoidoptical path complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent implements continuous useful action by redirecting non-conversion exciting light back through the phosphor coating via a mirror. This creates a closed-loop optical path where exciting light that was not initially converted is given another opportunity to convert, ensuring continuous utilization of light energy without adding complex external systems.

Inventive Principle:
Principle #20Continuity of useful action

3Ease of manufacture

If organic binders are used for phosphor coating, then the coating process is simple, but temperature-related issues occur

Engineering Contradiction:
Improvecoating process simplicityVSAvoidtemperature stability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent transitions from organic binders to inorganic binders for phosphor coating. This material substitution creates a composite structure where inorganic binder particles are dispersed in the phosphor layer, providing high-temperature stability and reliability while maintaining ease of manufacture through established coating processes.

Inventive Principle:
Principle #40Composite materials

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

This design improves brightness efficiency by ensuring all phosphor light is utilized and non-conversion exciting light is converted, resulting in increased light source apparatus efficiency.

Implementation Method 1

phosphor light which has been emitted from the phosphor

Methodology Applied
Scientific EffectPhotoluminescence: Photoluminescence

Implementation Method 2

the curvature of the condenser lens is set so that incident parallel light is converged to one position on the disk

Methodology Applied
Scientific EffectLens focusing: Lens

Implementation Method 3

non-conversion exciting light enters the phosphor coated to another portion through the taper portion

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP2466375B1Light Source Apparatus
Publication Date: 2019.12.25 MAXELL LTD
  • EP2466375B1 patent drawingFigure 1A~1C
  • EP2466375B1 patent drawingFigure 2
  • EP2466375B1 patent drawingFigure 3A~3C

AI summary

A light source apparatus which emits light from phosphor (7) by exciting light (2) and in which an efficiency of brightness is improved is provided. The light source apparatus has a light source (1, 23, 34, 36) which emits exciting light (2); and a metal member (6) to which the exciting light (2) is input, wherein the metal member (6) has a concave portion in a portion to which the exciting light (2) is input, and phosphor (7) to generate phosphor light (8) from the exciting light (2) is coated in the concave portion. The concave portion may have a taper shape. The phosphor (7) may be coated on at least two surfaces of the concave portion. The phosphor (7) may be coated on an area which is equal to or less than the half of a depth of the concave portion. A glass member (9) having a taper shape may be formed at an opening portion of the concave portion.