Automated LED Coating Apparatus for Uniform Phosphor Film

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Solution Overview

Problem

High-power LED coating with phosphor requires thin film thickness for optimal performance, but conventional methods face issues with unevenness due to poor wettability of silicone binders, leading to sedimentation and instability in coating weight, especially when using low-viscosity slurries with organic solvents, which complicates automation and increases production costs.

Innovation Solution

An automated coating method and apparatus that measures coating weight in a controlled environment, allowing for precise application and correction of coating amounts, using a pulsed application technique and adjacent coating and measurement chambers to minimize air flow interference, enabling efficient and accurate application of low-viscosity slurries with organic solvents.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If low-viscosity slurry with organic solvent is used to achieve thin film coating, then coating thickness is reduced and productivity is improved, but coating uniformity deteriorates due to sedimentation and poor wettability

Engineering Contradiction:
Improvecoating speedVSAvoidcoating uniformity
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies pulsed coating where the coating head moves periodically between coating and non-coating positions, creating intermittent application cycles. This periodic action allows the slurry to be applied in controlled bursts rather than continuous flow, preventing excessive buildup and improving uniformity while maintaining high productivity through rapid positioning

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent incorporates weight measurement feedback to monitor the actual coating amount in real-time. The system measures the weight of the LED component before and after coating, calculates the actual coating amount, and uses this information to adjust subsequent coating parameters. This closed-loop feedback control ensures consistent coating uniformity even when using low-viscosity slurries that are prone to sedimentation

Inventive Principle:
Principle #23Feedback

2Productivity

If automated coating system is implemented to improve productivity, then production efficiency is increased, but system complexity and cost increase

Engineering Contradiction:
Improveproduction efficiencyVSAvoidsystem complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The system performs self-measurement and self-correction through automated weight measurement and feedback control. The coating head itself is equipped with weight measurement functionality, allowing it to autonomously determine the coating amount and adjust subsequent operations without external intervention. This self-service capability reduces the need for complex external monitoring and control systems

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent combines multiple functions into the coating head assembly: coating application, weight measurement, and control functions are integrated into a single unit. This merging of functions eliminates the need for separate measurement devices and control systems, reducing overall system complexity while maintaining automated productivity

Inventive Principle:
Principle #5Merging (Combining)

3Manufacturing precision

If pulsed coating method is used to improve coating uniformity, then coating quality is enhanced, but coating time increases

Engineering Contradiction:
Improvecoating uniformityVSAvoidcoating cycle time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The pulsed coating system maintains continuous useful action by rapidly alternating between coating and positioning phases. The non-coating portions of the pulse cycle are used for repositioning the coating head or allowing slurry recovery, ensuring that time is not wasted but productively utilized. This continuous cycle approach minimizes idle time while maintaining the benefits of pulsed application

Inventive Principle:
Principle #20Continuity of useful action

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 ensures high-quality, thin coatings with improved uniformity and productivity by automating weight measurement and correction, reducing defects, and lowering production costs while maintaining hygiene and safety.

Implementation Method 1

measuring the weight of the object to be coated after the coating material has been applied

Methodology Applied
Scientific EffectWeight measurement:

Implementation Method 2

application by atomizing, and spraying

Methodology Applied
Scientific EffectSpray atomization:

Implementation Method 3

a low-viscosity coating material containing a volatile component such as a solvent

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentEP2805777B1Coating method and device
Publication Date: 2022.02.02 MTEK SMART
  • EP2805777B1 patent drawingFigure 1~2
  • EP2805777B1 patent drawingFigure 3~4
  • EP2805777B1 patent drawingFigure 5~6

AI summary

[PROBLEM TO BE SOLVED] To provide a method and apparatus for applying a coating material that reacts at ordinary temperatures and increases in viscosity with lapse of time or a coating material that is difficult to handle, such as an unstable slurry in which sedimentation occurs at high rate, to a high-value-added object to be coated. [SOLUTION] Before at least applying coating material to an object to be coated, the coating amount is automatically measured using a highly-accurate measuring device set in an atmosphere that does not substantially affect the measurement to control the coating amount during production. Therefore, high-quality products can be mass-produced with a low production cost.