Lens Driving Device Rack-Lead Angle Alignment
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Solution Overview
Problem
Existing lens driving devices face issues with lens frame leaning and image tremors due to inaccuracies in the leaning of the abutting face and the lead angles of the rack teeth and feed screw, which can lead to overload and prevent smooth movement along the optical axis.
Innovation Solution
A lens driving device with a rack member that has rack teeth leaning at an angle coinciding with the lead angle of the lead screw, supported by a spring member to generate a reaction force that crosses the face connecting the guide shafts, preventing the lens frame from rotating and ensuring stable movement along the optical axis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the rack teeth and abutting face are made to lean at an angle to generate reaction force, then the lens frame can move smoothly without trembling, but the accuracy of leaning is difficult to ensure and causes overload on the feed screw
Solution Approach 1:
The patent changes the parameter of the leaning angle to substantially coincide with the lead angle of the lead screw. This parameter alignment ensures that the reaction force generated by the meshing lead screw and rack teeth acts in a direction that crosses the face connecting the guide shafts, preventing lens frame rotation while avoiding overload on the lead screw.
Solution Approach 2:
The patent introduces asymmetric leaning of the rack teeth and abutting face at angles that coincide with the lead angle. This asymmetric configuration generates a reaction force with a horizontal component that creates a moment to counteract gravitational moment, preventing the lens frame from leaning or rotating during movement along the optical axis.
2Ease of operation
If the lead screw rotates to move the lens frame, then focusing or zooming is achieved, but the lens frame leans due to lead angles of the rack teeth and feed screw
Solution Approach 1:
The patent introduces asymmetric leaning of the rack teeth and abutting face at angles that coincide with the lead angle. This asymmetric configuration generates a reaction force with a horizontal component that creates a moment to counteract gravitational moment, preventing the lens frame from leaning or rotating during movement along the optical axis.
Solution Approach 2:
The patent uses the horizontal component of the reaction force generated by the leaning rack teeth as a counteracting force against the gravitational moment. This reaction force moment acts to prevent the lens frame from leaning, effectively balancing the destabilizing gravitational effect during lead screw rotation.
3Reliability
If the abutting face leans at an angle to prevent trembling, then image stability is improved, but power consumption increases due to overload
Solution Approach 1:
The patent changes the parameter of the leaning angle to substantially coincide with the lead angle of the lead screw. This parameter alignment ensures that the reaction force generated by the meshing lead screw and rack teeth acts in a direction that crosses the face connecting the guide shafts, preventing lens frame rotation while avoiding overload.
Solution Approach 2:
The patent uses the horizontal component of the reaction force generated by the leaning rack teeth as a counteracting force against the gravitational moment. This reaction force moment acts to prevent the lens frame from leaning, effectively balancing the destabilizing gravitational effect during lead screw rotation.
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
The solution prevents lens frame leaning and image tremors by ensuring the reaction force moment is greater than the sum of moments due to gravity and lead angle, allowing smooth and stable movement along the optical axis, reducing power consumption and preventing image jumps.
Implementation Method 1
a spring member configured to press the rack teeth toward the lead screw to generate reaction force acting from the lead screw toward the rack teeth
Implementation Method 2
a lead screw configured to mesh with the rack teeth, which each leans at an angle substantially coinciding with a lead angle of the lead screw, to move the lens frame forward or backward along the optical axis at a time of rotating in a clockwise direction or an anticlockwise direction
Data Source
AI summary
A lens driving device includes a focus lens frame, first and second shafts, a rack member, a lead screw and a spring member. One or more lenses are attached to the focus lens frame. The first and second guide shafts are arranged parallel to an optical axis of one or more lenses, inserted into first and second holes of the focus lens frame and guide the focus lens frame. The rack member is supported by the focus lens frame in the vicinity of the first hole. The lead screw meshes with rack teeth formed on the rack member to move the focus lens frame along the optical axis. The spring member presses the rack teeth toward the lead screw to generate reaction force acting from the lead screw toward the rack teeth. A direction in which the reaction force acts crosses a face connecting the first and second guide shafts.