Light Emitting Device Ring Gate Positioning

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Solution Overview

Problem

Conventional light emitting devices face issues with improper solder connections, reduced light output due to light absorption, and thermal resistance, primarily caused by the difficulty in aligning optical and color conversion members and the overflow of encapsulation resin.

Innovation Solution

The design incorporates a ring gate with centering projections to precisely position the optical member, prevent resin overflow, and includes a heat conducting plate with a sub-mount member to manage thermal stress, ensuring efficient light direction and heat dissipation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If the optical member is positioned to cover the LED chip, then light direction is improved, but alignment precision with LED chip and color conversion member deteriorates

Engineering Contradiction:
Improvelight directionVSAvoidalignment precision
Core Design Contradiction:
Illumination intensityVSManufacturing precision

Solution Approach 1:

The patent introduces a ring gate as an intermediary component between the optical member and the mounting substrate. This ring gate serves as a positioning structure that mediates the alignment between the optical member, LED chip, and color conversion member, enabling precise alignment while maintaining proper light direction coverage.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If encapsulation resin is injected into the recess to encapsulate the LED chip, then encapsulation is improved, but resin overflow to electrodes occurs causing poor solder connection

Engineering Contradiction:
ImproveencapsulationVSAvoidsolder connection quality
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent extracts the resin containment function from the recess structure and implements it through the ring gate. The ring gate acts as a barrier that extracts the overflow problem from the encapsulation process, allowing resin to be injected into the recess for proper encapsulation while preventing it from reaching the electrodes and compromising solder connections.

Inventive Principle:
Principle #2Taking out (Extraction)

3Power

If the mounting substrate is used to mount the light emitting device, then electrical connection is improved, but thermal resistance increases limiting input power

Engineering Contradiction:
Improveinput electric powerVSAvoidthermal resistance
Core Design Contradiction:
PowerVSTemperature

Solution Approach 1:

The patent introduces a heat conducting plate as an intermediary thermal management component between the LED chip and the mounting substrate. This heat conducting plate mediates the thermal path, providing improved heat dissipation while maintaining the electrical connection functions of the mounting substrate, thereby reducing thermal resistance and enabling higher input power.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 configuration enhances light output by preventing resin voids, improving solder connections, and reducing thermal resistance, allowing for higher input power and increased light flux.

Implementation Method 1

an optical member (an output-magnifying portion) 160 shaped like convex lens covering the LED chip

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 2

dome-shaped color conversion member (wavelength conversion member) 170 containing a phosphor

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 3

The phosphor is excited by a light emitted from LED chip and radiates a light of color different from the luminescent color of the LED

Methodology Applied
Scientific EffectPhotoluminescence: Photoluminescence

Implementation Method 4

a heat conducting plate with a sub-mount member to manage thermal stress, ensuring efficient light direction and heat dissipation

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP2197047B1Light emitting device
Publication Date: 2015.08.12 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD
  • EP2197047B1 patent drawingFigure 1
  • EP2197047B1 patent drawingFigure 2
  • EP2197047B1 patent drawingFigure 3

AI summary

The present invention provides a light emitting device, in which an encapsulation resin 50 is disposed at a space confined between an optical member 60 and a mounting substrate 20. This encapsulation resin is possibly made free from a void-generation therein. In this light emitting device, the optical member can be precisely positioned. An electrode disposed outside a color conversion member 70 is possibly free from an improper solder connection. A ring gate 27 is formed on the top surface of the mounting substrate 20 outside of the optical member 60, and acts to position the color conversion member 70. The ring gate 27 acts to prevent an overflowing liquid encapsulation resin from flowing to the electrode provided. The ring gate 27 is provided with a plurality of centering projections which are spaced circumferentially along its inner circumference to position the color conversion member 70.