Metal Cam Focus Adjustment for Optical Sensors
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Solution Overview
Problem
Existing optoelectronic sensors face limitations in focus adjustment accuracy due to the use of plastic injection molded cams, which are cost-limited and have a short lifespan, restricting the adjustability and durability of optical elements like lenses.
Innovation Solution
A metal cam with a varying radius, manufactured through etching technology, is used in conjunction with a transmission element and ball bearings to achieve precise and durable focus adjustment, allowing for a smooth roll-off edge and increased adjustability without significant cost increases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a plastic injection molded cam is used for focus adjustment, then production costs are reduced, but the service life and durability are limited
Solution Approach 1:
The patent changes the material parameter from plastic to metal (specifically aluminum alloy), transforming the cam from a disposable plastic component to a durable metal component that can be anodized, thereby resolving the contradiction between production cost and service life
Solution Approach 2:
The patent uses a composite approach by combining metal (aluminum alloy) with an anodization coating, creating a composite structure that provides both the mechanical strength of metal and the surface properties of a protective coating, enhancing both durability and cost-effectiveness
2Measurement precision
If a cam disc with linear slope over full rotation is used, then adjustment accuracy per step is increased, but the component becomes the limiting factor for service life due to plastic material
Solution Approach 1:
The patent changes the material parameter from plastic to metal alloy, allowing the cam to maintain its precise linear slope geometry while achieving unlimited service life through the durability of metal and anodization coating
3Ease of operation
If an eccentric unit with eccentrically mounted ball bearing is used, then focus adjustment is achieved, but the adjustment range is limited to half a revolution
Solution Approach 1:
The patent segments the cam structure into a multi-sided polygonal shape with multiple focal positions, allowing the ball bearing to roll along different sides and achieve adjustment ranges beyond half a revolution, thereby increasing adaptability while maintaining ease of operation
Solution Approach 2:
The patent makes the cam geometry dynamic by creating a polygonal shape where different sides provide different focal positions, allowing the adjustment mechanism to adapt to various ranging requirements beyond the static half-revolution limitation
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 metal cam provides robust and long-lasting focus adjustment with high precision, enabling rapid and frequent focusing over numerous cycles, suitable for applications requiring sharp image capture, such as camera-based code readers.
Implementation Method 1
The adjustment device uses a cam disk and a transmission element that is in contact with its circumference. Since the cam disk has a radius that varies around its circumference, in particular increasing linearly, it generates a linear adjustment movement during a rotational movement
Implementation Method 2
The transmission element preferably incorporates a ball bearing. The ball bearing rolls on the etched edge, which is particularly smooth
Data Source
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AI summary
An adjustment device (20) for an optical element (12) of an optoelectronic sensor (10) is described, comprising a drive (32), a cam disk (22) rotatable by the drive (32), and a transmission element (26) that is in contact with a circumference of the cam disk (22) and connected to the optical element (12) in order to convert a rotational movement of the cam disk (22) into an adjustment movement of the optical element (12). The cam disk (22) is manufactured from metal using etching technology.