LED Chip Cavity Phosphor Application

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Solution Overview

Problem

Existing methods for producing luminescence diode chips with luminescence conversion materials face challenges such as inhomogeneous phosphor distribution, manufacturing tolerances, and high costs due to the need for precise dosing and handling of abrasive materials, leading to color locus fluctuations and increased production costs.

Innovation Solution

A method involving a base body with a layer sequence for multiple luminescence diode chips, where a cover layer with photostructurable material is applied, cavities are introduced, and luminescence conversion material is applied to fill these cavities, allowing for precise shaping and application of the material, which can be cured and stripped, enabling well-defined and efficient application of the conversion material.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If phosphor is mixed into potting compound for encapsulation, then the LED chip is protected and light emission is achieved, but inhomogeneous phosphor distribution occurs leading to color locus fluctuations

Engineering Contradiction:
Improvecolor locus stabilityVSAvoidphosphor distribution uniformity
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The invention separates the phosphor application from the potting compound encapsulation. Instead of mixing phosphor into the potting compound, the phosphor is applied directly to the LED chip surface in a controlled manner, while the potting compound serves only for encapsulation and protection. This segmentation eliminates the inhomogeneous distribution problem.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The phosphor is applied to the LED chip before the final encapsulation step. This preliminary action allows for precise dosing and homogeneous distribution of phosphor particles on the chip surface before the potting compound is applied, ensuring uniform color emission.

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If precise dosing accessories are used for casting compound, then manufacturing precision is improved, but acquisition costs and wear and tear increase

Engineering Contradiction:
Improvecasting compound dosing precisionVSAvoiddosing accessory complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention extracts the phosphor dosing function from the casting compound dosing process. By applying phosphor directly to the LED chip separately from the potting compound application, the need for complex integrated dosing systems is eliminated, reducing both accessory complexity and wear from handling abrasive materials.

Inventive Principle:
Principle #2Taking out (Extraction)

3Power

If phosphor particles are abrasive, then luminescence conversion is effective, but wear and tear of dosing accessories increases

Engineering Contradiction:
Improveluminescence conversion efficiencyVSAvoiddosing accessory durability
Core Design Contradiction:
PowerVSEase of manufacture

Solution Approach 1:

The phosphor is applied to the LED chip in a preliminary step before final encapsulation, allowing for controlled placement using methods that minimize wear on dosing accessories. The phosphor can be applied as a slurry or suspension that is then cured or fixed in place, reducing the abrasive impact on subsequent handling equipment.

Inventive Principle:
Principle #10Preliminary action

4Adaptability or versatility

If manufacturing tolerances vary for LED chip positioning, then production flexibility is maintained, but color locus fluctuations occur

Engineering Contradiction:
Improvemanufacturing tolerance flexibilityVSAvoidcolor locus consistency
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The invention applies phosphor directly to the local area of the LED chip where light emission occurs. This localized application ensures that the phosphor is positioned precisely where needed, compensating for variations in chip positioning during assembly and maintaining consistent color emission despite manufacturing tolerances.

Inventive Principle:
Principle #3Local quality

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 method allows for the production of luminescence diode chips with a well-defined luminescence conversion material distribution, reducing color locus fluctuations and manufacturing costs, while enabling precise control over the emission characteristics and structure of the luminescence diode chips.

Implementation Method 1

introducing the cavity into the cover layer (3) by photostructuring

Methodology Applied
Scientific EffectPhotopolymerisation: Photopolymerisation

Implementation Method 2

The phosphor can be excited by an electromagnetic primary radiation emitted by the LED chip and emits a secondary radiation, the primary radiation and the secondary radiation having different wavelength ranges

Methodology Applied
Scientific EffectPhotoluminescence: Photoluminescence

Data Source

PatentEP1917686B9Method for producing an LED chip and LED chip
Publication Date: 2018.10.24 OSRAM OPTO SEMICON GMBH & CO OHG
  • EP1917686B9 patent drawingFigure 1~4
  • EP1917686B9 patent drawingFigure 5~7
  • EP1917686B9 patent drawingFigure 8~10

AI summary

The invention relates to a method, according to which a base is provided, with a series of layers for an LED chip, suitable to emit electromagnetic radiation. A cover layer is applied to at least one main surface of the base. At least one cavity is introduced into the cover layer, the cavity being completely or partially filled with a luminescence conversion material. The luminescence conversion material uses at least one fluorescent substance. The invention also relates to a method, according to which the cover layer comprises photostructurable material and at least one fluorescent substance, so that it acts as luminescence conversion material and can be directly photostructured. Also disclosed are LED chips that can be produced using said method.