LED Phosphor Encapsulation With Sacrificial Layer Flash Prevention

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Solution Overview

Problem

Existing methods for producing optoelectronic semiconductor devices, such as LEDs, face challenges in avoiding mold flash on the radiation exit side, which can lead to yield loss and require additional steps like wet blasting that risk damaging the device.

Innovation Solution

The method involves applying a sacrificial layer to the top side of the phosphor body or LED chip, followed by film-assisted molding to create a reflective encapsulation body. The sacrificial layer is then removed, either thermally or through wet blasting, to avoid or remove mold flash, thereby ensuring a clean radiation exit side.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If film assisted molding is used to produce reflective encapsulation body, then the encapsulation body can be formed around LED chip and phosphor body, but mold flash occurs on the radiation exit side

Engineering Contradiction:

Improveencapsulation body formationVSAvoidradiation exit side cleanliness

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

A sacrificial layer is applied to the phosphor body before the molding process. This preliminary action prepares the surface to prevent mold flash adhesion during subsequent molding operations.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The sacrificial layer acts as an intermediary between the mold and the phosphor body. It provides a temporary surface that prevents direct contact and adhesion of mold flash to the radiation exit side during the molding process.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Manufacturing precision

If wet blasting is used to remove mold flash, then mold flash can be removed from the device, but the device may be damaged

Engineering Contradiction:

Improvemold flash removalVSAvoiddevice integrity

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The sacrificial layer is a disposable temporary component that is removed after serving its purpose. It is designed to be easily removed through simple processes like picking or gentle cleaning, avoiding the need for aggressive wet blasting that could damage the device.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

Instead of using harmful aggressive removal methods like wet blasting that risk device damage, the patent converts the potential harm into a benefit by using a sacrificial layer that enables gentle, safe removal processes while still achieving complete mold flash elimination.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Manufacturing precision

If additional steps like wet blasting are added to remove mold flash, then mold flash can be removed, but production time and complexity increase

Engineering Contradiction:

Improvemold flash removalVSAvoidproduction efficiency

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The sacrificial layer is applied in advance before molding, so that mold flash removal can be achieved through simple subsequent steps rather than requiring complex post-processing operations. This preliminary preparation streamlines the overall production process.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The sacrificial layer extracts and isolates the mold flash removal function from the main production process. By separating this function into a dedicated temporary layer, the complex wet blasting step is replaced with simple removal operations that maintain productivity.

Inventive Principle:

Principle #2Taking out (Extraction)

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 approach allows for high yields in producing optoelectronic semiconductor devices by eliminating the need for additional steps like wet blasting, reducing the risk of damage to the device, and ensuring effective removal of mold flash.

Implementation Method 1

The sacrificial layer is then removed, either thermally or through wet blasting

Methodology Applied

Scientific EffectThermal decomposition: Pyrolysis

Implementation Method 2

The phosphor body is for partial or complete wavelength conversion of the light emitted by the light-emitting diode chip

Methodology Applied

Scientific EffectLuminescence: Luminescence

Data Source

PatentUS12266744B2Method for producing optoelectronic semiconductor devices and optoelectronic semiconductor device

Publication Date: 2025.04.01 OSRAM OPTO SEMICON GMBH & CO OHG

AI summary

In an embodiment a method includes providing a light-emitting diode chip and a phosphor body, applying a sacrificial layer to a top side of the phosphor body only, placing the phosphor body onto the light-emitting diode chip, molding an encapsulation body directly around the light-emitting diode chip and the phosphor body by a film assisted molding, wherein at least in places a top face of the sacrificial layer facing away from the phosphor body remains unsealed with a molding film, and removing the sacrificial layer so that the top side of the phosphor body is free of the sacrificial layer.