Optical Unit Lens Frame Sliding Mechanism for Endoscope Miniaturization
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Solution Overview
Problem
Miniaturization of image pickup apparatuses, such as those used in cellular phones and endoscopes, is hindered by high viscosity resistance from grease or oil used to reduce friction in sliding lens frames, making it difficult to drive the moving lens frame with small-sized actuators.
Innovation Solution
The optical unit employs a moving lens frame that slides within a fixed barrel using spherical bodies and guide grooves, with strategically placed magnets generating magnetic forces orthogonal to the optical axis to cancel out attractive forces and create a consistent urging force, allowing the moving lens frame to move smoothly along the optical axis with a small driving force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If grease or oil is used to reduce friction in the sliding lens frame, then the frictional coefficient is reduced, but viscosity resistance increases making it difficult to drive with small actuators
Solution Approach 1:
The patent extracts and eliminates the grease/oil lubrication system from the sliding mechanism. Instead of using lubricants between the lens frame and barrel, it employs spherical bodies that roll along guide grooves, completely removing the source of viscosity resistance while maintaining low friction through rolling contact.
Solution Approach 2:
The patent replaces the traditional sliding friction mechanism with a rolling friction mechanism. By substituting direct surface contact with spherical bodies rolling in guide grooves, it transforms the mechanical interaction from high-friction sliding to low-friction rolling, eliminating the need for lubricants and reducing the force required to drive the lens frame.
2Ease of operation
If a guide shaft and sleeve configuration is used, then the moving lens frame can be driven, but the high frictional coefficient requires large driving force from the actuator
Solution Approach 1:
The patent introduces spherical bodies as the core element of the driving mechanism. These spheres roll within guide grooves to propel the lens frame, utilizing curved surface contact instead of flat sliding surfaces. This spheroidal approach dramatically reduces friction and the power required to move the lens frame compared to traditional guide shaft and sleeve configurations.
Solution Approach 2:
The patent transforms the static sliding contact into a dynamic rolling motion. The spherical bodies actively roll along the guide grooves rather than simply sliding, creating a dynamic mechanism that reduces friction through rolling contact. This dynamic approach allows the lens frame to be driven with minimal power from small actuators.
3Volume of moving object
If miniaturization is pursued, then the image pickup apparatus size is reduced, but the actuator becomes even smaller and cannot overcome viscosity resistance
Solution Approach 1:
The patent replaces the lubrication-based friction reduction system with a rolling friction system that is inherently more efficient. By using spherical bodies that roll in guide grooves, it eliminates viscosity resistance entirely, allowing miniaturized actuators to generate sufficient driving force to move the lens frame without being constrained by lubricant viscosity.
Solution Approach 2:
The patent fundamentally changes the friction parameter from sliding friction (high) to rolling friction (low). This parameter change in the friction mechanism allows the system to operate with minimal driving force, enabling the use of smaller actuators and overall miniaturization of the image pickup apparatus while maintaining smooth lens frame 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
This configuration enables the smooth operation of the moving lens frame without enlargement, effectively reducing the size of the image pickup apparatus and allowing for efficient zoom and focus functions even with small-sized actuators.
Implementation Method 1
an invention of an image pickup apparatus including an optical unit adopting ball sliding by rolling friction
Implementation Method 2
a plurality of magnets disposed so as to generate magnetic force in a direction orthogonal to the optical axis; and a plurality of magnetic members disposed at facing positions of the plurality of magnets, and configured to cancel attractive force in an opposite direction generated among the plurality of magnets by the magnetic force and generate urging force only in a constant direction of bringing the plurality of spherical bodies into contact with the guide grooves at the moving frame
Data Source
AI summary
An optical unit includes: a moving frame disposed so as to freely move back and forth inside a fixed barrel and configured to hold a moving lens; an actuator configured to drive the moving frame along an optical axis of the moving lens; a plurality of spherical bodies configured to make the moving frame slidable; a plurality of guide grooves configured to guide the plurality of spherical bodies; a plurality of magnets disposed so as to generate magnetic force in a direction orthogonal to the optical axis; and a magnetic member disposed at a facing position of the plurality of magnets, and configured to cancel attractive forces in opposing directions generated with the plurality of magnets by the magnetic force and generate urging force only in a direction of bringing the plurality of spherical bodies into contact with the guide grooves at the moving frame.