LED Filament Manufacturing Viscosity Control
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Solution Overview
Problem
The existing manufacturing methods for LED filaments face issues with light distribution due to precipitation and agglomeration of fluorescent powders in the covering glue, leading to subpar performance in LED bulbs.
Innovation Solution
A manufacturing method involving a support, chip fixing, first baking, dispensing of covering glue with a viscosity of 5000 to 50000 mPa·S, and a second baking process to ensure uniform dispersion and curing of the glue, preventing precipitation and ensuring good light distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If fluorescent powder is mixed in covering glue, then the LED bulb can emit white light, but the fluorescent powder precipitates and agglomerates causing poor light distribution
Solution Approach 1:
The patent changes the viscosity parameter of the covering glue to a specific range (5000-50000 mPa·S) to optimize the dispersion and stability of fluorescent powder, preventing precipitation while maintaining good light distribution
Solution Approach 2:
The patent performs a first baking process before dispensing the covering glue to pre-cure the die-attach adhesive and stabilize the LED chips on the support, creating an optimal base for subsequent glue application and fluorescent powder dispersion
2Ease of manufacture
If the covering glue has low viscosity for good fluidity, then it is easy to dispense, but the fluorescent powder precipitates easily
Solution Approach 1:
The patent identifies and controls the viscosity parameter of the covering glue within a specific range (5000-50000 mPa·S) that balances both dispensing ease and fluorescent powder stability, preventing precipitation while maintaining manufacturability
3Device complexity
If the die-attach adhesive is not pre-cured before dispensing glue, then the process is simpler, but the LED chips are not firmly fixed causing defects
Solution Approach 1:
The patent implements a first baking process before glue dispensing to pre-cure the die-attach adhesive and firmly fix the LED chips on the support, ensuring reliability before subsequent manufacturing steps
Solution Approach 2:
The patent divides the manufacturing process into distinct sequential steps: first baking for die-attach adhesive curing, then glue dispensing, and finally second baking for covering glue curing, with each step serving a specific function to ensure overall product 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 results in high-yield LED filaments with stable and consistent light transmittance, meeting reliability and light flux requirements, while maintaining a simple and cost-effective process.
Implementation Method 1
fixing chips in which LED chips are fixed to the support with a die-attach adhesive
Implementation Method 2
performing a first baking in which the support fixed with the LED chips is placed in a baking device for baking
Implementation Method 3
performing a second baking in which the semi-finished product covered with the covering glue is placed into the baking device for baking, so as to obtain the LED filament after baking
Implementation Method 4
dispensing a glue in which a semi-finished product manufactured in S3 is covered with a covering glue with a viscosity of 5000 to 50000 mPa·S
Data Source
AI summary
A manufacturing method of an LED filament and a manufacturing method of a bulb are provided. The steps are as follows: step S1, preparing a support; step S2, fixing chips; step S3, performing a first baking and performing a lighting test after cooling; step S4, dispensing a glue in which a semi-finished product is covered with a covering glue, and a viscosity of the covering glue used is 5000 to 50000 mPa·S; and step S5, performing a second baking. According to the disclosure, the preparation of the LED filament is completed through support preparing, chip fixing, the first baking, dispensing and the second baking, and the covering glue selected during dispensing has good fluidity, and the fluorescent powders mixed in the covering glue can be uniformly dispersed, thus preventing precipitation or agglomeration and ensuring good light distribution.