Integrated Nest Structure for Plastic Optical Element Molding
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Solution Overview
Problem
Conventional nest structures for molding plastic optical elements, especially those with uneven thickness, often result in sink marks and air bubbles due to uneven temperature distribution and thermal contraction, affecting optical performance and productivity.
Innovation Solution
A plastic optical element with a support portion integrated into the same nest structure as the optical element body, featuring a concave laser beam incident portion and a ribbed design, which allows for uniform temperature distribution and reduced air inflow during molding, preventing sink marks and air bubbles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional nest structures with separate members for optical element body and support portion are used, then the optical element can be molded, but sink marks and air bubbles occur due to air flow into joint surfaces
Solution Approach 1:
The patent merges the optical element body and support portion into a single integral molded piece, eliminating the joint surface between separate members. This integration prevents air flow into joint surfaces during injection molding, thereby eliminating sink marks and air bubbles that would otherwise occur at the interface between connected members.
2Manufacturing precision
If injection pressure is increased to fill cavity and solve external defects, then sink marks are reduced, but inner distortion occurs especially at thin portions
Solution Approach 1:
The patent optimizes the injection molding parameters including injection pressure, cooling temperature, and cycle time to achieve uniform resin temperature distribution in the die. By carefully controlling these parameters, the patent fills the cavity completely without causing excessive pressure that would lead to internal distortion, while still preventing sink marks through proper pressure management.
3Productivity
If cooling speed varies due to uneven lens thickness, then molding is faster, but temperature distribution becomes non-uniform causing sink marks
Solution Approach 1:
The patent implements localized cooling channels and heating elements positioned strategically within the die to compensate for uneven thickness distribution. Thinner portions receive reduced cooling or localized heating, while thicker portions receive enhanced cooling, ensuring uniform temperature distribution across the entire optical element despite variations in thickness that enable faster molding.
4Ease of manufacture
If conventional nest structures are used for long unevenly shaped optical elements, then molding is possible, but sink marks increase due to air flow into joint surfaces
Solution Approach 1:
The patent employs a single integral nest structure that molds the entire long unevenly shaped optical element without joint surfaces. This eliminates air flow paths into joints that would cause sink marks, while the nest structure is designed with appropriate gating and venting systems to handle the long uneven geometry effectively.
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 enables continuous molding with reduced external defects, maintaining optical performance and improving mass productivity by eliminating sink marks and air bubbles, particularly at the gate side where air inflow is most significant.
Implementation Method 1
it is preferable that in cooing solidification process of molten resin in a cavity of a die
Implementation Method 2
in cooing solidification process of molten resin in a cavity of a die
Implementation Method 3
or thermal contraction varies in the die, resulting in external defects such as sink marks
Data Source
AI summary
A plastic optical element is provided, which includes an optical element body having a transfer surface which includes at least one laser beam incident portion of a concave shape, and a support portion connected with the optical element body, in which the support portion is disposed in a direction of a tangent line at an end of the transfer surface, and the optical element body and a part of the support portion are molded in the same nest structure.