Optical Information Reader Lens Retainer Positioning
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Solution Overview
Problem
Optical information readers face issues with one-sided blur affecting resolution and misalignment of irradiation ranges between visible and invisible light, leading to suboptimal focus adjustment and reading performance, especially when switching between different light modes.
Innovation Solution
The optical information reader incorporates a lens retainer with a reference surface parallel to the optical axis, allowing slidable contact with a guide surface on the holder, which minimizes the influence of one-sided blur by maintaining the imaging lens's position relative to the area sensor, and arranges visible and invisible light illuminants in line along the short-side direction of the light-receiving surface to align their irradiation ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the relative positions of the area sensor and imaging lens are adjusted by changing the amount of threadable engagement of the lens barrel, then the focus position can be determined, but one-sided blur causes rotation about the optical axis leading to resolution variation and inaccurate focus adjustment
Solution Approach 1:
The patent introduces a lens retainer as an intermediary component between the lens barrel and the holder. This lens retainer includes a reference surface that is brought into surface contact with a guide surface on the holder, serving as a mediator to establish and maintain the correct relative position between the imaging lens and area sensor without relying on threadable engagement alone.
Solution Approach 2:
The patent replaces the threadable engagement mechanism (screw threads) with a surface contact mechanism (reference surface on guide surface). This substitution eliminates the rotation about the optical axis that occurs with threaded adjustments, providing more stable and accurate positioning of the imaging lens relative to the area sensor.
2Reliability
If visible light and invisible light illuminants are used separately, then reading performance can be improved for different code types, but misalignment of irradiation ranges occurs leading to reading failures
Solution Approach 1:
The patent merges the visible light illuminant and invisible light illuminant into a single integrated illumination system. Both illuminants are arranged in line along the short-side direction of the light-receiving surface, ensuring that their irradiation ranges are properly aligned and overlap correctly on the target surface, thereby eliminating reading failures caused by misalignment.
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 enhances focus adjustment accuracy and reading performance by stabilizing the imaging lens's position and ensuring proper alignment of light ranges, reducing the impact of one-sided blur and misalignment, thereby improving resolution and reading reliability.
Implementation Method 1
an imaging lens 25 for transmitting light from the information code C to the area sensor 23 and forming an image on the sensor
Implementation Method 2
an illuminant 21 capable of emitting illumination light Lf
Implementation Method 3
the holder is provided with a guide surface with which the reference surface is brought into surface contact and against which the reference surface is brought into slidable contact
Data Source
AI summary
An optical information reader includes an imaging lens and a lens retainer retaining the imaging lens and assembled, in this state, into the holder. The lens retainer includes a flange bottom surface and end faces as a reference surface that is parallel to an optical axis of the imaging lens. The holder includes a top surface and edge faces as a guide surface. The guide surface is brought into surface contact with the flange bottom surface and the end faces when the lens retainer is assembled into the holder, and is brought into slidable contact with the flange bottom surface and the end faces when the lens retainer is moved along the optical axis. Thus, influence of one-sided blur is minimized in terms of variation in resolution which is measured when obtaining an optimal focus position by changing relative positions of the area sensor and the imaging lens.