Focal Plane Shutter Intermediate Plate Chevron Edges
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Solution Overview
Problem
Miniaturization of focal plane shutters for cameras leads to increased frictional resistance between shutter blades and plate members, causing unstable exposure times and uneven exposure during high-speed photography, especially when the space interval between blade chambers is reduced.
Innovation Solution
The focal plane shutter design includes an intermediate plate with oblong exposure openings and chevron-shaped contour forming edges, reducing the contact area between blades and plate members, allowing for stable operation even with smaller space intervals between blade chambers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the space interval between blade chambers is reduced to achieve miniaturization, then the camera size is reduced, but the frictional resistance between shutter blades and plate members increases causing unstable exposure times
Solution Approach 1:
The patent extracts and removes portions of the intermediate plate to create through-holes or open spaces. This reduces the contact area between the shutter blades and the intermediate plate, thereby decreasing frictional resistance and allowing stable exposure times even when the blade chambers are positioned closer together for miniaturization.
Solution Approach 2:
The intermediate plate is designed with a porous or perforated structure containing through-holes. This porous configuration reduces the effective contact area between blades and plate while maintaining structural integrity, enabling reduced frictional resistance in compact camera designs.
2Volume of moving object
If the space interval between blade chambers is reduced for miniaturization, then camera size decreases, but uneven exposure occurs during high-speed photography
Solution Approach 1:
By removing portions of the intermediate plate to create through-holes, the patent reduces frictional resistance that would otherwise cause uneven exposure during high-speed photography. This allows the shutter blades to move smoothly and uniformly even in compact configurations.
3Strength
If the contact area between blades and plate members is increased, then structural stability improves, but frictional resistance increases causing operational instability
Solution Approach 1:
The patent removes portions of the intermediate plate to create through-holes, thereby reducing the contact area between shutter blades and plate members. This decreases frictional resistance and improves operational stability while maintaining sufficient structural strength through strategic placement of remaining plate material.
Data Source
AI summary
A first blade includes two arms and four blades, and is arranged between a shutter base plate and an intermediate plate. A second blade includes two arms and four blades, and is arranged between the intermediate plate and an auxiliary base plate. During an exposure operation, the four blades of the first blade are brought into an overlap state from a development state and the four blades of the second blade are brought into the development state from the overlap state. Since a contour forming edge of the intermediate plate above the opening portion is formed in the shape of an arc, the four blades of the second blade are able to start an operation appropriately from the overlap state.