Dome Camera Edge Part Astigmatism Elimination
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Solution Overview
Problem
Conventional dome cameras suffer from astigmatism due to differing focal powers in the meridian and sagittal directions caused by conical and spherical surface combinations, limiting their imaging quality and application.
Innovation Solution
A dome camera design featuring a spherical surface part with an edge part having revolving surfaces where the focal power in both the meridian and sagittal directions is made substantially equal by using conical and annular surfaces connected tangentially, ensuring that light beams can be focused on the same point, thereby eliminating astigmatism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conical surface and spherical surface are connected to form the dome cover, then the de-molding performance is ensured and processing is simplified, but astigmatism occurs due to different focal powers in meridian and sagittal directions
Solution Approach 1:
The patent applies local quality by differentiating the surface geometry between the central area and edge area of the dome cover. The central area maintains a spherical surface for optimal optical properties, while the edge area uses a conical surface with specifically designed focal power to match the spherical surface. This local differentiation allows each region to serve its specific function while maintaining overall imaging quality.
Solution Approach 2:
The patent changes the geometric parameters of the conical surface in the edge area, specifically designing its focal power in both meridian and sagittal directions to be equal to that of the spherical surface. By adjusting the conical surface's curvature and orientation parameters, the patent eliminates astigmatism while preserving the benefits of the conical geometry for de-molding and processing.
2Volume of moving object
If the dome cover is made with a super-hemispherical shape to utilize internal space, then space utilization is improved, but astigmatism and imaging blur are generated due to inherent optical defects
Solution Approach 1:
The patent applies local quality by dividing the dome cover into a central spherical area and an edge conical area. The central spherical area provides the necessary internal space utilization, while the edge conical area with matched focal power compensates for optical defects. This local differentiation allows the dome to maintain its space-efficient super-hemispherical shape while eliminating astigmatism in the imaging path.
3Manufacturing precision
If the focal power in meridian and sagittal directions is made equal in the edge part, then astigmatism is eliminated and imaging quality is improved, but the structural complexity increases
Solution Approach 1:
The patent uses composite geometric surfaces by combining a spherical surface in the central area with a conical surface in the edge area. Both surfaces are made from the same material but have different geometric configurations. The conical surface is specifically designed with focal power matching the spherical surface, creating a composite structure that eliminates astigmatism while maintaining manufacturing feasibility through a single-m material construction.
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 design eliminates astigmatism, providing clear imaging by ensuring equal focal power in both directions, enhancing the imaging quality and expanding the application scope of dome cameras.
Implementation Method 1
After light beams pass through the dome cover, light beams in the meridian direction and the sagittal direction thereof cannot be focused on the same point
Data Source
Figure 1~2
Figure 3
AI summary
Disclosed is a dome camera, including a spherical surface part (A) positioned in the centre and an edge part (B) connected thereto, wherein an internal surface (3) and an external surface (4) of the edge part (B) are revolving surfaces, and a revolution axis thereof is parallel to that of the spherical surface part (A); the internal surface (3) is in a direction away from the spherical surface part (A) from a joint with the spherical surface part (A), with a monotonically increasing revolution radius; and focal power in both a meridian direction and a sagittal direction of the edge part (B) is the same as that of the spherical surface part (A). Since the dome cover is arranged such that the focal power in the meridian direction and the sagittal direction of the edge part (B) of the dome camera is the same as that of the spherical surface part (A), after light beams pass through the dome cover, light beams in the meridian direction and the sagittal direction of the dome cover can be focused on the same point, thereby eliminating astigmatism induced by the fact that the meridian direction and the sagittal direction cannot be focused on the same point in the conventional art, and providing favorable conditions for obtaining clear imaging.