Resin Lens Reference Face Molding for Optical Axis Alignment
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Solution Overview
Problem
Conventional resin lenses for optical pickup devices face challenges in achieving high optical accuracy due to errors in manufacturing and molding processes, particularly related to the alignment and rotation of inserts in injection molds, which can lead to misalignment of the optical axis and interference with the mounting process.
Innovation Solution
The resin lens design incorporates a reference face formed on the flange section, molded by a combination of first and second molds, where the reference face is annular and positioned close to the inner periphery, allowing for accurate positioning and fixing, and the flange section is molded to include a linear portion to prevent cutting marks from interfering with mounting, while the optical functional face is formed by a rotatable insert to maintain optical axis alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a rotatable insert is used to form the optical functional section, then the optical axis alignment can be adjusted, but manufacturing errors and rotation errors cause misalignment between the reference face and optical functional face
Solution Approach 1:
The mold is divided into a first mold (stationary) that forms the reference face and a second mold (rotatable insert) that forms the optical functional section. This segmentation allows independent optimization of each component's positioning accuracy while maintaining the ability to adjust optical axis alignment through controlled rotation of the insert during the molding process.
2Ease of manufacture
If the gate section is cut at one position on the outer periphery, then the resin lens can be extracted from the molded product, but the cutting mark interferes with the mounting process
Solution Approach 1:
The gate section is positioned asymmetrically on the outer periphery of the resin lens, specifically designed so that the cutting mark falls on a non-critical area that does not interfere with mounting operations. The asymmetric placement allows the gate to be located at a position optimized for extraction while ensuring the cutting mark does not coincide with mounting reference faces or critical optical surfaces.
3Measurement precision
If the reference face is formed on the flange section, then the resin lens can be positioned and fixed accurately, but the angle between the reference face and optical functional face may be erroneous due to molding errors
Solution Approach 1:
The optical axis serves as an intermediary reference that connects the reference face and the optical functional face. By designing the system such that both faces are referenced to the optical axis, any angular errors are minimized because the optical axis provides a stable, consistent reference frame that eliminates cumulative positioning errors between the two faces.
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 enhances the optical accuracy of the resin lens by preventing errors in the angle between the reference face and the optical functional face, reducing misalignment, and avoiding interference from cutting marks, thus improving the overall quality of the optical device.
Implementation Method 1
a molded product, which is extracted from the injection mold, is obtained by filling the sprue, the runners, the gates, and the cavities with a resin and hardening the resin by cooling
Data Source
AI summary
A resin lens includes an optical functional section that has an optical function, and a flange section that is formed around the optical functional section. A reference face is used as reference during positioning and fixing, and is formed on one face of the flange section. The face on which the reference face is formed is molded by an insert that mainly forms the optical functional section and a holder that mainly forms the flange section, during molding. The reference face of the flange section and an optical functional face that is the face of the optical functional section facing the reference face are molded by the insert, and a face of the flange section that is closer to the outer periphery than the reference face of the flange section is molded by the holder.