Screw-In Lens Module Biasing Structure for Backlash Control
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Solution Overview
Problem
Screw-in lens modules experience backlash and inclination issues due to manufacturing tolerances and errors, leading to time-consuming adjustments of the imaging sensor to compensate for lens barrel inclinations during focus adjustments.
Innovation Solution
A lens module design featuring a lens barrel with a threaded portion, a lens holder with a threaded portion and a biasing member, where the biasing member is sandwiched between the lens barrel and holder to maintain alignment and reduce inclination by applying a constant biasing force orthogonal to the optical axis, thereby stabilizing the lens barrel and imaging sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a screw-in lens module is used to adjust focus by rotating the lens barrel, then the lens barrel can be moved along the optical axis direction, but backlash occurs between the threaded portions due to tolerances and manufacturing errors, causing the lens barrel to incline with respect to the lens holder and imaging sensor
Solution Approach 1:
A biasing member is introduced as an intermediary component between the lens barrel and lens holder. This biasing member applies a constant biasing force to the lens barrel, preventing backlash and inclination caused by manufacturing tolerances in the threaded portions, while still allowing focus adjustment through rotation
Solution Approach 2:
The biasing member pre-applies a biasing force to the lens barrel in the radial direction before focus adjustment begins. This preliminary action maintains the lens barrel's alignment with the lens holder throughout the focusing operation, eliminating the need for post-adjustment inclination corrections
2Reliability
If the lens barrel is biased toward the center of the optical axis by the reaction force of elastic deformation, then backlash is suppressed, but the position where the reaction force is generated changes when the lens barrel is rotated, causing changes in lens barrel inclination
Solution Approach 1:
The biasing member serves as a mediator that distributes the biasing force uniformly around the circumference of the lens barrel. This intermediary component ensures that the reaction force acts consistently at all positions, preventing inclination changes during rotation while maintaining backlash suppression
Solution Approach 2:
The biasing member transitions from a relaxed state to a compressed state as the lens barrel is screwed into the lens holder, maintaining constant contact and uniform force distribution. This phase transition ensures stable inclination throughout the focusing operation
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
Reduces changes in lens barrel inclination, simplifies focus adjustment, and enhances sealing against dust and water intrusion with a simple configuration, minimizing the need for additional components and adjustments.
Implementation Method 1
the biasing member biasing the lens barrel toward the lens holder by contacting the protruding part
Data Source
AI summary
Provided is a lens module with a lens barrel for holding a lens and having a threaded portion on an outer peripheral surface; a lens holder for holding the lens barrel to be movable along an optical axis direction of the lens, the lens holder having a threaded portion on an inner peripheral surface, the threaded portion of the lens barrel and the threaded portion of the lens holder being screwed together; and a biasing member arranged between the outer peripheral surface of the lens barrel and the inner peripheral surface of the lens holder, with a protruding part formed on a part of the inner peripheral surface of the lens holder, and with the biasing member biasing the lens barrel toward the lens holder by contacting the protruding part.