Lens Unit Cover Member Quadrangular Prism Shape
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Solution Overview
Problem
Conventional lens units for endoscopes require skilled artisans for precise manufacturing, leading to high costs and production inefficiencies due to the need for hand-polished cylindrical cover glasses with specific dimensions and chamfered corners, resulting in limited product numbers and inaccurate image formation if light beam displacement occurs.
Innovation Solution
A lens unit design featuring a cover member with polygonal prism side surfaces, such as quadrangular, hexagonal, or octagonal shapes, that can be easily manufactured by cutting or molding, eliminating the need for hand-polishing and allowing for precise contact with the holder, ensuring the light beam's effective area remains within the light receiving area, thus preventing displacement and improving image accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a cylindrical cover glass with precise dimensions and chamfered corners is manufactured by handwork of skilled artisans, then the manufacturing precision and image formation accuracy are improved, but the productivity and manufacturing cost are worsened
Solution Approach 1:
The patent changes the cross-sectional shape parameter of the cover glass from circular to quadrangular. This parameter change allows the cover glass to be manufactured by simple cutting or molding processes instead of requiring hand-polishing, thereby improving productivity while maintaining sufficient manufacturing precision for the application
Solution Approach 2:
The patent extracts the requirement for high-precision handwork by eliminating the need for chamfered corners and perfect circularity. The quadrangular shape with contact corners simplifies the manufacturing process by removing complex finishing operations, allowing mass production without skilled artisans
2Manufacturing precision
If the cover glass is manufactured with handwork to achieve complete roundness, then the manufacturing precision is improved, but the manufacturing cost increases
Solution Approach 1:
The patent changes the geometric parameter from circular cross-section to quadrangular cross-section. This simplifies manufacturing by allowing standard cutting or molding techniques to be used instead of expensive hand-polishing processes, reducing manufacturing cost while achieving the required optical performance
Solution Approach 2:
The quadrangular cover glass can be manufactured using inexpensive, automated processes such as cutting or molding. The simplified design allows for mass production with low-cost equipment, eliminating the need for expensive skilled labor and specialized tooling
3Stability of the object's composition
If a circular light receiving area is used with a cylindrical cover glass, then the shape symmetry is improved, but the risk of light beam displacement outside the light receiving area increases
Solution Approach 1:
The patent introduces asymmetry in the form of specific corner contacts between the quadrangular cover glass and the holder. This asymmetric contact configuration provides stable positioning that prevents rotation and displacement, ensuring the light beam remains aligned with the light receiving area while using a non-circular shape
Data Source
AI summary
The present invention provides a lens unit having a cover member which does not cause deviation in precision and capable of being manufactured efficiently at low cost. In a lens unit 10A, side surfaces of a cover member 14a continuing from a front end surface 29 to a rear end surface located at a lens side are formed in a regular quadrangular prism, at least two of corners of the regular quadrangular prism are in contact with an inner peripheral surface 27 of a housing space 17 of a holder 11a for housing the cover member 14a, a gap 34 is formed between each of the side surfaces of the cover member 14a and the inner peripheral surface 27 of the holder 11a, and an effective area of a light beam is located inside a light receiving area having a regular quadrangular shape surrounded by an outer peripheral edge of the front end surface 29 of the cover member 14a.