Optical Device Cam Mechanism Lens Actuation
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Solution Overview
Problem
Existing optical devices that perform zooming and focusing by moving a lens unit in the optical axis direction often result in complex configurations and durability issues with energization members, which can negatively impact optical performance.
Innovation Solution
An optical device design featuring a fixed tube with a straight groove, a cam ring with a cam groove, and an auxiliary cam follower that moves in conjunction with the cam follower but not the cam groove, allowing the lens unit to move along the optical axis without intersecting forces that could distort the optical axis, using a simple configuration without an energization member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If an energization member is used to move the lens unit in the optical axis direction, then the lens unit can be actuated, but the configuration becomes complicated and durability is reduced
Solution Approach 1:
The patent replaces the energization member (electromechanical actuator) with a purely mechanical cam mechanism. The cam ring rotates to drive the cam follower, which in turn moves the lens unit along the optical axis through the straight groove. This mechanical substitution eliminates the need for motors, solenoids, or other energization members, thereby simplifying the configuration while maintaining actuation capability.
Solution Approach 2:
The cam follower serves as an intermediary element that translates the rotational motion of the cam ring into linear motion of the lens unit. The cam follower engages with both the cam groove (for driving motion) and the straight groove (for guiding motion), acting as a mediator that converts rotational actuation into precise linear displacement without requiring direct mechanical coupling or energization members.
2Ease of operation
If an energization member is used to move the lens unit, then the lens unit can be actuated, but durability is reduced
Solution Approach 1:
By replacing the energization member with a passive cam mechanism, the patent eliminates components subject to electrical wear, magnetic field degradation, and complex mechanical failures. The cam and cam follower mechanism consists of simple geometric surfaces that wear uniformly and can be easily replaced, significantly improving durability and reliability.
3Productivity
If the lens unit moves in the optical axis direction, then zooming and focusing are achieved, but forces may incline the optical axis and degrade optical performance
Solution Approach 1:
The patent separates the driving function (cam groove) from the guiding function (straight groove) by using two distinct groove structures. The cam groove provides the driving force for lens unit movement, while the straight groove constrains the motion to precisely follow the optical axis direction. This segmentation of functions ensures that the lens unit moves accurately along the optical axis without inclination, maintaining optical performance.
Solution Approach 2:
The straight groove acts as a guiding intermediary that constrains the cam follower's motion to the optical axis direction. By engaging the cam follower with the straight groove, the mechanism ensures that the lens unit moves precisely along the optical axis, preventing any inclination or deviation that would degrade optical performance while still allowing the cam groove to provide the necessary driving forces.
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 design effectively suppresses the influence on optical performance during lens unit movement by dispersing forces that could incline the optical axis, maintaining the lens unit's posture and reducing complexity and durability concerns.
Implementation Method 1
a cam ring that has a cam groove extending in a second direction intersecting to the first direction; a cam follower that is engaged with the straight groove and the cam groove; When the fixed tube and the cam ring relatively rotate, the lens unit moves in the first direction
Implementation Method 2
an auxiliary cam follower that is engaged with the straight groove and that is not engaged with the cam groove. When the fixed tube and the cam ring relatively rotate, the lens unit moves in the first direction
Data Source
AI summary
An optical device includes a fixed tube that has a straight groove extending in a first direction parallel to an optical axis of the optical device, a cam ring that has a cam groove extending in a second direction intersecting to the first direction, a cam follower that is engaged with the straight groove and the cam groove, a lens unit that moves in conjunction with the cam follower in the first direction, and an auxiliary cam follower that is engaged with the straight groove and that is not engaged with the cam groove. When the fixed tube and the cam ring relatively rotate, the lens unit moves in the first direction. Further, the lens unit is fixed to the cam follower and the auxiliary cam follower.