Single-Motor Zoom Lens for Barcode Readers
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Solution Overview
Problem
Conventional imaging-based bar code readers require multiple motors for zoom lens systems, increasing complexity and cost, while failing to effectively extend the working range and field of view due to the need for separate motors for focal length adjustment and focusing.
Innovation Solution
A simplified zoom lens assembly that uses a single motor to move a movable lens group along a path parallel to the optical axis, allowing for simultaneous adjustment of focal length and focusing, with a stationary lens group and a movable lens group that maintains image plane alignment with the sensor array.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional zoom lens system is used with separate motors for focal length adjustment and focusing, then the working range and field of view can be extended, but the device complexity and cost increase
Solution Approach 1:
The patent combines the focal length adjustment mechanism and focusing mechanism into a single integrated system. The movable lens group is driven by a single motor that moves the lens group along a path parallel to the optical axis, simultaneously achieving both focal length variation and focusing functions that would traditionally require separate motors.
Solution Approach 2:
The single motor-driven movable lens group performs multiple functions: it adjusts focal length to extend working range and simultaneously focuses the image on the sensor array. This multi-functional design eliminates the need for dedicated separate mechanisms for each function, reducing overall system complexity.
2Device complexity
If a single motor is used to move the movable lens group, then device complexity is reduced, but the ability to independently adjust focal length and focus may be compromised
Solution Approach 1:
The patent employs a dynamic lens group configuration where the movable lens group can be positioned at different locations along a path parallel to the optical axis. By varying the position of the movable lens group along this path, the system dynamically adjusts both focal length and focus simultaneously through a single motor's motion control.
Solution Approach 2:
The system changes optical parameters (focal length and focus position) by moving the movable lens group along a predetermined path. The motor controls the position parameter of the lens group, and this single parameter change results in simultaneous adjustments of multiple optical functions, maintaining operational flexibility despite using a single motor.
3Productivity
If the movable lens group is moved along a path parallel to the optical axis, then simultaneous focusing and focal length variation is achieved, but the image plane alignment may be affected
Solution Approach 1:
The lens system is segmented into stationary and movable lens groups. The movable lens group is specifically designed to move along a path parallel to the optical axis, separating the focusing function from the focal length adjustment function in terms of mechanical motion. This segmentation allows precise control of image plane alignment while achieving simultaneous focusing.
Solution Approach 2:
The movable lens group acts as an intermediary element that mediates between the object and the sensor array. By moving this intermediate lens group along a controlled path, the system achieves simultaneous focusing and focal length variation while maintaining proper image plane alignment through the lens group's specific motion trajectory.
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 solution reduces complexity and cost by using a single motor, enabling variable focal length and field of view while maintaining image quality across the working range, allowing for effective decoding of bar codes at various distances without the need for additional motors.
Implementation Method 1
Light reflected from the target bar code is focused through a system of one or more lens of the imaging system onto the sensor array
Implementation Method 2
a zoom lens assembly projecting light from the field of view onto the sensor array
Data Source
AI summary
A variable focus imaging lens assembly for an imaging-based bar code reader for imaging a target bar code within a field of view of the imaging system, the imaging lens assembly comprising a simplified zoom lens assembly or system that provides for both focusing and adjustment of focal length of the imaging lens assembly with movement of a single group of movable lenses using one motor. The zoom lens assembly includes a stationary lens group comprising a plurality of stationary lenses and a movable lens group comprising a plurality of movable lenses movable with respect to a sensor array of the imaging system. The movable lens group is driven by a motor along a path of travel parallel to an optic axis of the imaging lens assembly, at least one lens of the plurality of stationary lenses being intermediate a pair of lenses of the plurality of movable lenses.