Resin Flow Changing Section for Display Device Molding

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Solution Overview

Problem

The existing resin molded article manufacturing method for display devices suffers from appearance defects due to resin rebound during the injection process, leading to uneven resin density and surface issues like whitening or pattern formation, which cannot be effectively reduced without altering molding conditions.

Innovation Solution

The method involves using a resin flow changing section to alter the resin flow path, reducing momentum and rebound by branching the resin flow, which is injected from a resin injection gate and directed towards a cavity formed by multiple dies, thereby minimizing uneven resin density and surface defects without changing the molding conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the resin is ejected directly from the resin ejection port into the cavity, then the molding process is simple and efficient, but the resin rebounds and causes appearance defects on the exterior surface

Engineering Contradiction:
Improvemolding efficiencyVSAvoidappearance quality
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

A resin flow changing section is introduced as an intermediary component between the resin injection gate and the cavity. This section modifies the resin flow path and reduces resin momentum before the resin reaches the exterior surface, thereby preventing rebound and appearance defects while maintaining efficient molding processes

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If the injection speed is reduced to prevent resin rebound, then appearance defects are reduced, but the molding cycle time increases and productivity decreases

Engineering Contradiction:
Improveappearance qualityVSAvoidmolding cycle efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The resin flow changing section acts as a mediator that reduces resin momentum without requiring changes to injection parameters. By providing an alternative flow path that reduces kinetic energy, the system achieves appearance quality improvement while maintaining high injection speeds and short cycle times

Inventive Principle:
Principle #24Intermediary (Mediator)

3Manufacturing precision

If the cavity space is enlarged to reduce resin rebound, then appearance defects are reduced, but the product dimensions increase and may not meet design requirements

Engineering Contradiction:
Improveappearance qualityVSAvoidproduct dimensions
Core Design Contradiction:
Manufacturing precisionVSShape

Solution Approach 1:

The resin flow changing section provides a solution that reduces appearance defects without modifying the cavity dimensions or product size. By controlling resin flow dynamics rather than physical space, the invention maintains precise product dimensions while improving surface quality

Inventive Principle:
Principle #24Intermediary (Mediator)

4Manufacturing precision

If a resin flow changing section is added to control resin flow, then appearance defects are reduced, but the die structure becomes more complex

Engineering Contradiction:
Improveappearance qualityVSAvoiddie structure complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The resin flow changing section is designed as a relatively simple intermediary component that can be integrated into the existing die structure. By focusing the complexity only in the flow modification section rather than the entire die system, the invention achieves appearance quality improvement with minimal increase in overall structural complexity

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 approach effectively reduces appearance defects such as whitening and pattern formation on the exterior surface of the resin molded article by controlling resin flow and momentum, maintaining optimal molding conditions while improving the quality of the resin molded article.

Implementation Method 1

the resin will have less momentum as compared to a case in which the ejected resin reaches the exterior surface directly, and therefore rebound of the resin can be reduced in the cavity

Methodology Applied
Scientific EffectMomentum reduction through collision: Impact Force

Data Source

PatentEP3950258A1Resin molded article manufacturing method and display device
Publication Date: 2022.02.09 FUNAI ELECTRIC CO LTD
  • EP3950258A1 patent drawingFigure 1
  • EP3950258A1 patent drawingFigure 2
  • EP3950258A1 patent drawingFigure 3

AI summary

A resin molded article manufacturing method comprises forming a cavity having a shape corresponding to a resin molded article by bringing a plurality of resin molding dies into contact with each other, and forming the resin molded article by injecting a resin directly from a resin ejection port into a resin injection gate and filling the cavity with the resin. The forming of the resin molded article includes filling the cavity with the resin while changing a flow of the resin that is headed from the resin injection gate directly toward the cavity by a resin flow changing section that is provided opposite the resin injection gate.