Bayonet Lens Mount with Screw-Driven Movable Portion
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Solution Overview
Problem
Interchangeable lenses in image pickup apparatuses are prone to rattling due to the flexure of spring members in bayonet type lens mounts, leading to potential image quality degradation, and contact failure occurs when lenses are mounted or dismounted without rotational engagement, resulting in self-cleaning issues.
Innovation Solution
A lens mount design featuring a fixed portion, a stationary mount portion, a movable mount portion with pawls, and arm portions that rotate to engage bayonet pawls, providing secure attachment and preventing rattling, while ensuring contact terminal alignment for self-cleaning during mounting and dismounting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If spring members are used to urge the interchangeable lens toward the image pickup apparatus body in a bayonet type lens mount, then the lens can be held in place, but the lens becomes rattled due to flexure of the spring members
Solution Approach 1:
The lens mount is divided into a stationary mount portion and a movable mount portion. The movable mount portion can move in the optical axis direction and rotate, allowing it to independently adjust to accommodate different lens sizes and weights while maintaining stable engagement with the lens bayonet pawls, thereby eliminating rattling without requiring excessive spring force that would cause flexure.
Solution Approach 2:
The movable mount portion is designed to be dynamically adjustable in both the optical axis direction (via screw engagement) and rotational position (via arm portions). This dynamic capability allows the system to adapt to varying lens characteristics while maintaining firm, rattling-free engagement, resolving the contradiction between holding force and stability.
2Ease of operation
If the interchangeable lens is mounted to and dismounted from the image pickup apparatus body by being linearly moved without rotation, then mounting is simplified, but contact terminal portions do not rub against one another resulting in contact failure
Solution Approach 1:
The mounting operation merges two actions: linear movement along the optical axis and rotational movement. As the movable mount portion rotates during engagement, it causes the contact terminal portions to rub against one another, performing a self-cleaning operation that ensures reliable electrical contact while maintaining simplified single-hand operation for the user.
Solution Approach 2:
The rotational engagement mechanism enables the contact terminals to automatically clean themselves through friction during the mounting process. This self-cleaning function is performed passively as part of the normal mounting operation, without requiring additional user action or maintenance intervention, thereby ensuring reliable electrical contact.
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
The design allows for easy mounting and dismounting of interchangeable lenses without rattling, enhances image quality by preventing lens movement, and ensures reliable electrical contact through self-cleaning of terminal portions.
Implementation Method 1
a first screw portion, a movable mount portion having pawls configured for engagement with the bayonet pawls of the interchangeable lens and having a second screw portion configured for threaded engagement with the first screw portion
Implementation Method 2
an elastic member for causing the conduction part to be in press-contact with the contact pins
Implementation Method 3
the interchangeable lens and the image pickup apparatus body are rotated relative to each other in a state that a mount face of the interchangeable lens abuts against amount face of the image pickup apparatus body, thereby engaging pawled portions of these mount faces with one another
Data Source
AI summary
An image pickup apparatus having a lens mount capable of easily mounting and dismounting an interchangeable lens to and from an image pickup apparatus body and capable of preventing the interchangeable lens mounted to the image pickup apparatus body from being rattled. In the lens mount, by rotating a movable mount portion about an optical axis from a state where bayonet pawls of the interchangeable lens and pawls of the movable mount portion do not overlap with one another as viewed in an optical axis direction, the movable mount portion moves toward a first fixed portion in the optical axis direction with the progress of engagement between a female screw portion of a stationary mount portion and a male screw portion of the movable mount portion, whereby the pawls and the bayonet pawls are brought in abutment with one another.