Lens Barrel Back End Outer Diameter Reduction
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Solution Overview
Problem
The existing lens barrel designs face challenges in reducing the outer diameter of the back end section when a member moving in the optical axis direction is disposed at the back end, leading to potential interference with camera body components and reduced degree of freedom in arrangement.
Innovation Solution
The design incorporates a fixed cylinder, a guide cylinder, and a rotary cylinder with a helicoid power transmission mechanism that allows the guide cylinder and lens holding frames to move in the optical axis direction without requiring a cam mechanism on the outer circumference, thereby reducing the outer diameter of the back end section.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a restriction roller is attached to the outer circumferential surface of the second transmission cylinder to move the second transmission cylinder in the optical axis direction, then the lens holding frame can be moved in the optical axis direction, but the outer diameter of the back end section of the lens barrel is increased
Solution Approach 1:
The patent relocates the power transmission mechanism from the radial dimension (outer circumferential surface) to the axial dimension (front end section). The cam groove is formed on the front end section of the first transmission cylinder rather than on its outer circumferential surface, and the restriction roller is attached to the front end section of the second transmission cylinder rather than its outer circumferential surface. This dimensional relocation allows the lens holding frame to move in the optical axis direction while preventing increase in the outer diameter of the back end section.
2Power
If the first transmission cylinder and second transmission cylinder are arranged with the cam groove on the outer circumferential side, then the power transmission function is achieved, but the degree of freedom in arrangement of camera body components is reduced
Solution Approach 1:
The patent changes the spatial arrangement of the power transmission components from a radial configuration (cam groove on outer circumferential surface) to an axial configuration (cam groove on front end section). This repositioning in the axial dimension eliminates the protrusion at the back end section, thereby restoring the degree of freedom in arranging camera body components and allowing more flexible component layout.
3Ease of operation
If the intermediate rotary cylinder and first transmission cylinder rotate together with the focus ring, then the focusing function is achieved, but the outer diameter of the back end section increases due to the cam groove location
Solution Approach 1:
The patent relocates the cam groove from the outer circumferential surface to the front end section of the first transmission cylinder, and attaches the restriction roller to the front end section of the second transmission cylinder. This allows the intermediate rotary cylinder and first transmission cylinder to continue rotating together with the focus ring for focusing operation, while simultaneously reducing the outer diameter of the back end section by eliminating the radial protrusion.
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 configuration effectively minimizes the outer diameter of the lens barrel's back end section, preventing interference with camera body components and enhancing the degree of freedom in component arrangement while maintaining optical performance.
Implementation Method 1
a first power transmission mechanism 26 is provided between the front end section of the guide cylinder 17 and the rotary cylinder 18, the first power transmission mechanism 26 converting a rotary motion of the rotary cylinder 18 into a linear motion of the guide cylinder 17 in the optical axis direction
Data Source
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AI summary
To provide a lens barrel that is to be attached to a camera body and can reduce an outer diameter of a back end section of the lens barrel even when a member moving in an optical axis direction is disposed on the back end section of the lens barrel. A lens barrel 1 includes a fixed cylinder 3, a lens holding frame 14 that is disposed on an inner circumferential side of the fixed cylinder 3 and can move in an optical axis direction relative to the fixed cylinder 3, a guide cylinder 17 that is disposed on an outer circumferential side of the fixed cylinder 3 and can move, together with the lens holding frame 14, in the optical axis direction relative to the fixed cylinder 3, and a rotary cylinder 18 that is disposed on the outer circumferential side of the fixed cylinder 3 and can rotate relative to the fixed cylinder 3. A front end section of the guide cylinder 17 and the rotary cylinder 18 are disposed further on a front side than a connection part 41 that connects the lens holding frame 14 and the guide cylinder 17. A power transmission mechanism 26 is disposed between the front end section of the guide cylinder 17 and the rotary cylinder 18. The power transmission mechanism 26 converts a rotary motion of the rotary cylinder 18 into a linear motion of the guide cylinder 17 to cause the guide cylinder 17 and the lens holding frame 14 to move in the optical axis direction.