Variable Lead Focusing Unit for Rapid Precise Optical Adjustment
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Solution Overview
Problem
Existing optical devices, such as binoculars, face challenges in achieving both rapid and precise focusing from infinity to a close distance due to limitations in the helicoid mechanism, where either rapid focusing is easy but precise focusing is difficult, or vice versa.
Innovation Solution
A focusing unit with a screw body and nut body meshing via a cam follower, featuring a rotation restricting and releasing mechanism, allowing the nut body to move parallel to the optical axis for rapid focusing and enabling fine adjustments by allowing the nut body to rotate when the cam follower is released, thus allowing precise control over the optical member's movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a helicoid mechanism with long lead is used, then rapid focusing over entire range is achieved, but precise focusing becomes difficult
Solution Approach 1:
The invention applies dynamics by making the lead of the helicoid mechanism variable rather than fixed. The lead changing portion allows the lead to be long during most of the focusing range for rapid adjustment, and short near the infinity focus position for precise adjustment. This dynamic adjustment of the mechanism's characteristics resolves the contradiction between speed and precision.
Solution Approach 2:
The invention changes the parameter of lead length along the optical path. By having the lead vary from long to short as the optical member approaches the infinity focus position, the system achieves both rapid focusing over the entire range and precise focusing at critical positions. This parameter change resolves the technical contradiction.
2Measurement precision
If a helicoid mechanism with short lead is used, then precise focusing is achieved, but rapid focusing over entire range becomes difficult
Solution Approach 1:
The helicoid mechanism dynamically adjusts its lead length based on the focusing position. Rather than using a uniformly short lead, the mechanism transitions from long lead to short lead, combining the advantages of both approaches. This resolves the contradiction by applying short lead only where precision is needed while maintaining speed elsewhere.
Solution Approach 2:
The lead parameter is changed along the focusing trajectory. The lead is long for most of the range to enable rapid focusing, then becomes short near the infinity position to enable precise adjustment. This parameter variation resolves the contradiction between overall focusing speed and precision at specific positions.
3Measurement precision
If operation knob is turned many times for full range focusing, then precise focusing is achieved, but operational complexity and time increase
Solution Approach 1:
The varying lead mechanism dynamically adapts to the focusing stage. During coarse focusing, the long lead allows rapid coverage of the entire range with minimal rotations. Near the infinity position, the short lead automatically provides fine control. This dynamic adaptation reduces operational complexity while maintaining precision.
Solution Approach 2:
The lead parameter changes from long to short as focusing progresses, enabling the user to achieve both rapid full-range adjustment and precise infinity focus with a single continuous operation. This parameter change reduces the number of rotations needed compared to a uniformly short lead mechanism.
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
Enables rapid and precise focusing from infinity to a close distance, allowing users to adjust focus quickly and finely, enhancing the operational efficiency and usability of optical devices.
Implementation Method 1
a screw body put into rotation via the rotation of an operation member, a nut body meshing with the screw body
Implementation Method 2
a nut body meshing with the screw body and including a cam follower
Implementation Method 3
a cam follower, a cam follower restricting means including a rotation restricting portion for restricting the cam follower from rotating
Data Source
AI summary
A focusing mechanism allowing a user to adjust the focus from infinity to a close distance rapidly and precisely, and an optical device utilizing such a focusing mechanism. The focusing unit includes an optical member movable along an optical axis of an optical system, a screw body put into rotation via the rotation of an operation member, a nut body meshing with the screw body and including a cam follower, a cam follower restricting means including a rotation restricting portion for restricting the cam follower from rotating or revolving about a rotation or revolution axis of the operation member, and a rotation restriction releasing portion for releasing the restriction which prevents the rotation or revolution of the cam follower about the rotation or revolution axis of the operation member, and an optical member moving means for moving the optical member along the optical axis via the movement of the nut body along its rotation axis.