LED Package Lead-Frame Structure for Thermal Stress Sealing

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

In light-emitting devices with multiple elements, thermal stress from heat generation can lead to detachment and a decrease in airtightness, particularly at bonding areas with low strength, such as between lead terminals and frame bodies.

Innovation Solution

The design incorporates a frame body with a smaller thickness to facilitate deformation and reduce thermal stress, combined with plate bodies of greater thickness to securely fix lead terminals, thereby maintaining airtightness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If lead terminals are bonded to through-holes of frame body, then electrical connection is achieved, but bonding strength is low and gaps are likely to be generated

Engineering Contradiction:
Improvebonding strengthVSAvoidbonding area
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The patent extends the bonding structure from a two-dimensional surface bond to a three-dimensional through-hole penetration. Lead terminals are inserted through holes that penetrate the frame body, creating bonding interfaces at both the front and rear surfaces. This dimensional transition increases the effective bonding area and creates mechanical interlocking, significantly enhancing bonding strength and preventing gap formation under thermal stress.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Strength

If frame body thickness is increased to strengthen bonding, then bonding strength improves, but thermal stress increases due to heat generation

Engineering Contradiction:
Improvebonding strengthVSAvoidthermal stress
Core Design Contradiction:
StrengthVSStress or pressure

Solution Approach 1:

The patent divides the bonding function into multiple segments: the lead terminal passes through the frame body and creates separate bonding interfaces at the front surface and rear surface. This segmentation allows the bonding strength to be distributed across multiple areas rather than concentrated in a single thick bonding layer, reducing thermal stress while maintaining overall bonding strength.

Inventive Principle:
Principle #1Segmentation

3Reliability

If plate bodies are added to fix lead terminals, then airtightness is improved, but device complexity increases

Engineering Contradiction:
ImproveairtightnessVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The plate bodies serve multiple functions simultaneously: they provide mechanical support for the lead terminals, create sealing surfaces for airtightness, and distribute thermal stress. By integrating these multiple functions into a single component, the patent improves airtightness without proportionally increasing device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 effectively reduces thermal stress and maintains airtightness in light-emitting devices, even with high heat generation from multiple light-emitting elements, while also reducing manufacturing costs.

Implementation Method 1

due to heat generated by the light-emitting elements and the like, thermal stress may be applied to each member

Methodology Applied
Scientific EffectThermal stress: Thermal Expansion

Data Source

PatentEP3246957B1Light-emitting device and package for a light-emitting device
Publication Date: 2025.02.19 NICHIA CORP
  • EP3246957B1 patent drawingFigure 1A~1B
  • EP3246957B1 patent drawingFigure 1C
  • EP3246957B1 patent drawingFigure 1D

AI summary

A light-emitting device includes a base body (12); light-emitting elements mounted on an upper surface (12A) of the base body (12); a frame body (14) bonded to the upper surface (12A) of the base body (12), the frame body (14) including inner lateral surfaces (14B), outer lateral surfaces (14A), and first through-holes that extend through the frame body (14) in a lateral direction; lead terminals (15) that extend through the first through-holes, and each of which is electrically connected to the light-emitting elements; a cover (80) bonded to the frame body (14); plate bodies (16) bonded to an outer lateral surface (14A) or inner lateral surface (14B) of the frame body (14), each of the plate bodies (16) having one or more second through-holes, wherein each of the lead terminals (15) extends through a respective through-hole; and fixing members (17), each of which is disposed in a second through-hole and fixes a respective one of the one or more lead terminals (15).