Single Prism Auto-Focus Mechanism for Compact Barcode Readers
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing imaging-based bar code readers lack a compact and high-speed auto-focus mechanism, leading to difficulties in capturing clear images of bar codes over varying distances, especially in handheld devices where manual focusing is impractical and commercially available auto-focus systems are large, slow, and power-intensive.
Innovation Solution
A compact auto-focus system using a single moving prism within the optical path of the imaging system, which adjusts the light path length to achieve focus by shifting the prism along a fixed path, allowing for precise control of the focal length and image clarity without increasing device size, utilizing a combination of laser ranging and passive focusing techniques to determine object distance and optimize image contrast.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If a bi-focal system with movable lens is used for auto-focus, then focusing capability is improved, but device size increases
Solution Approach 1:
The patent replaces the mechanical lens-movement system with an optical path modification approach. A fixed lens remains stationary while a movable prism adjusts the light path length to achieve focus, eliminating the need for mechanical lens displacement and reducing device complexity and size.
Solution Approach 2:
The movable prism acts as an intermediary element between the fixed lens and the sensor array. By inserting or removing the prism from the optical path, the system adjusts focus without moving the lens itself, enabling auto-focus functionality in a compact form factor.
2Extent of automation
If commercially available auto-focus systems are used, then focusing automation is improved, but power consumption increases
Solution Approach 1:
The patent replaces power-intensive motor-driven lens systems with a low-power mechanical prism adjustment mechanism. The prism can be moved using simple actuators or even manual adjustment, dramatically reducing power consumption compared to electromagnetic motor systems.
3Extent of automation
If commercially available auto-focus systems are used, then focusing automation is improved, but response speed decreases
Solution Approach 1:
The patent replaces slow motor-driven lens systems with a faster mechanical prism adjustment mechanism. The prism can be rapidly inserted or removed from the optical path, enabling high-speed focus adjustment that meets the requirements of high scan rate barcode reading applications.
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
Enables high-quality image capture of bar codes over a range of distances with reduced device size and power consumption, ensuring efficient and accurate barcode reading in both handheld and fixed installations.
Implementation Method 1
A single prism moves along a path of travel to control a path length of light passing through the lens to the pixel array
Implementation Method 2
an optical system having one or more focusing lenses fixed with respect to the pixel array to transmit an image of a target object toward said pixel array from a focusing lens which includes a curved exit surface facing the pixel array
Data Source
AI summary
The disclosed bar code reader includes an auto-focusing component for rapidly producing in focus images. An imaging system makes use of an aiming pattern that impinges upon the coded indicia of a target. The imaging system includes a light monitoring pixel array and a focusing lens that is fixed with respect to the pixel array for transmitting an image of the target object onto the pixel array. The imaging system also includes a moveable prism mounted for movement along a path of travel to transmit light passing through the focusing lens onto the pixel array. A drive motor moves the prism relative the lens to adjust a focus of an image of the object formed at the pixel array.