Dome Cover Thickness Gradient Suppresses Weldlines
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Solution Overview
Problem
Existing dome covers for pan tilt cameras face challenges in suppressing weldline generation and image distortion due to uneven resin flow during injection molding, which affects the thickness and optical properties, particularly at the boundary surface between the curved and skirt sections.
Innovation Solution
A dome cover design with a thickness that continuously decreases from the top section to the opening end section, matching the resin flow timing between the curved and skirt sections, and an injection molding die configuration that adjusts spacing to synchronize resin progress, ensuring consistent resin flow and reducing weldline formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thickness of the skirt section is uniformly made small to slow down resin flow timing, then weldline generation is suppressed, but a difference in thickness occurs at the boundary surface causing image deterioration
Solution Approach 1:
The patent applies local quality by making the skirt section thickness non-uniform: the thickness is smaller at the distal end and larger at the boundary surface with the curved section. This localized thickness variation allows the resin flow timing to be adjusted (suppressing weldlines) while maintaining thickness uniformity at the optical boundary surface, thus preventing image deterioration.
2Reliability
If temperature is changed in a portion of the mold to match resin progress timing, then weldline generation is suppressed, but the design and temperature management becomes complicated
Solution Approach 1:
The patent applies parameter changes by modifying the geometric parameter (thickness) of the skirt section instead of changing the temperature parameter. This approach achieves the same effect of matching resin progress timing and suppressing weldlines, but avoids the complexity of temperature control systems and mold design modifications.
3Ease of manufacture
If the thickness of the dome cover is uniform at the curved section and skirt section, then manufacturing is simpler, but image deterioration occurs due to the boundary surface
Solution Approach 1:
The patent applies local quality by creating a localized thickness variation at the skirt section, specifically making the thickness larger at the boundary surface with the curved section. This ensures thickness uniformity at the optical boundary to prevent image deterioration, while still maintaining relatively simple manufacturing processes.
Data Source
AI summary
The invention provides a dome cover, a camera device, an injection molding die, and an injection molding method in which generation of a weldline is suppressed and deterioration of an acquired image is suppressed. In one aspect of the invention, a dome cover is a dome cover that covers a camera. The dome cover includes a curved section having a curved shape and a skirt section having a cylinder shape and has a top section at the curved section and an opening end section at the skirt section. The thickness of the dome cover is largest at the top section and smallest at the opening end section, and continuously decreases from the top section toward the opening end section. The inner diameter and the outer diameter of the dome cover continuously increase from the top section toward the opening end section.