Plastic Lens Mold Ejection Pin Positioning
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Solution Overview
Problem
In the manufacturing of plastic lenses for camera lens units, there is a challenge in reducing distortion and maintaining the quality of black coating on flange parts, especially when press-fitted into lens barrels, which can lead to ghosting and flare issues, particularly at high view angles.
Innovation Solution
A manufacturing method using a metal mold with a fixed and movable mold setup, where the flange part is formed with a black coating on the image side face, and an ejector pin is used to push out the plastic lens from the mold, preventing distortion and ensuring the quality of the black coating by separating the outer peripheral part and the black coating area, and positioning the ejector pin to avoid adverse effects on the lens face.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If black coating is applied to flange parts to prevent ghosting and flare, then optical quality is improved, but manufacturing complexity increases due to additional coating processes and quality control requirements
Solution Approach 1:
The flange part is divided into two distinct regions: a black coating part for light shielding and an outer peripheral part for ejection. This segmentation allows the black coating to be applied only where needed for optical quality while simplifying the manufacturing process by separating the functional zones.
Solution Approach 2:
The black coating is applied locally to specific portions of the flange part rather than the entire surface. This local quality approach maintains optical quality by providing light shielding only where necessary, while reducing manufacturing complexity by limiting the coating process to specific areas.
2Productivity
If ejector pin is used to push out plastic lens from mold, then productivity is improved, but distortion may occur on the lens face
Solution Approach 1:
The ejection function is extracted from the lens face area and assigned to the outer peripheral part of the flange. The ejector pin pushes against the outer peripheral part rather than the lens face, enabling efficient ejection while preventing distortion of the optical surface.
Solution Approach 2:
The outer peripheral part of the flange acts as an intermediary between the ejector pin and the lens. Instead of the ejector pin directly contacting the lens face, it contacts the outer peripheral part, which transmits the ejection force without causing distortion to the optical surface.
3Ease of manufacture
If ejector pin pushes outer peripheral part for ejection, then ease of manufacture is improved, but black coating quality may deteriorate due to unevenness or peeling
Solution Approach 1:
The flange is segmented into a black coating part and an outer peripheral part, with the ejector pin acting only on the outer peripheral part. This segmentation prevents the ejector pin from disturbing the black coating, maintaining coating quality while enabling easy ejection.
Solution Approach 2:
The ejection function is extracted from the black coating area and assigned to the outer peripheral part. This separation ensures that the black coating remains undisturbed during ejection, preventing unevenness or peeling while maintaining ease of manufacture.
Data Source
AI summary
A manufacturing method of a plastic lens formed by using a metal mold having a fixed mold and a movable mold. The plastic lens comprises a flange part surrounding a lens face, and an image side face of the flange part comprises a black coating part and an outer peripheral part. The manufacturing method may include a molding process in which the plastic lens is molded by using the fixed mold for molding an object side lens face and the movable mold for molding an image side lens face and the flange part, a mold opening process in which the metal mold is opened by moving the movable mold, and a pushing-out process in which the outer peripheral part is pushed out by an ejector pin disposed in the movable mold when the mold opening process is performed or, after the mold opening process has been performed.