Optical Code Reader Compact Design Using Beam Splitter
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Solution Overview
Problem
Imager-based optical code readers face challenges in reading shiny labels due to direct reflection issues and outgoing illumination being reflected back onto the imager, leading to reduced image quality and difficulty in achieving a compact design.
Innovation Solution
The design incorporates a pivoting mechanism and acute-angle orientation of mirrors and printed circuit boards relative to the window, along with a three-bounce mirror configuration, to direct incoming light paths away from the imager and reduce back-reflection, allowing for a compact and efficient optical code reader configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the imager is positioned to read optical codes directly through the window, then the reading function is simple and direct, but light from shiny labels reflects directly back onto the imager causing uniform reflection that washes out the desired image
Solution Approach 1:
A beam splitter is introduced as an intermediary optical element between the window and the imager. The beam splitter directs incoming light at a 45-degree angle away from the imager while allowing the imager to capture reflected light from optical codes on shiny surfaces, thereby eliminating direct reflection interference
Solution Approach 2:
The optical path is made asymmetric by positioning the imager at a 45-degree angle relative to the window rather than directly behind it. This asymmetric arrangement ensures that light reflected from shiny labels at normal incidence does not enter the imager, while light from optical codes at angled incidence is successfully captured
2Volume of moving object
If the window is positioned close to the imager for compact design, then the device size is reduced, but outgoing illumination reflects off the rear and front sides of the window back onto the imager washing out the image
Solution Approach 1:
The beam splitter serves as a mediator that redirects the optical path at 45 degrees, preventing direct back-reflection from the window from entering the imager. This allows the window to be positioned close to the imager for compact design while eliminating the harmful back-reflection effect
Solution Approach 2:
The optical path is redirected into a different spatial dimension by using the beam splitter to change the light path angle. This dimensional change in the optical path allows compact physical arrangement while maintaining optical separation between the window and imager
3Area of stationary object
If the distance from imager to scanner nose is increased to achieve larger view size, then the view area is increased, but the device becomes less compact and more difficult to position
Solution Approach 1:
The optical path is folded using the beam splitter to redirect light at 45 degrees, effectively increasing the optical path length and view area without increasing the physical distance between the imager and scanner nose. This allows large view size in a compact device form factor
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 the ability to read optical codes from various angles and orientations while maintaining a compact form factor, reducing the impact of direct and back-reflected light on image quality and enabling a larger window read area.
Implementation Method 1
The design incorporates a pivoting mechanism and acute-angle orientation of mirrors and printed circuit boards relative to the window, along with a three-bounce mirror configuration, to direct incoming light paths away from the imager and reduce back-reflection
Data Source
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AI summary
A data reader (10, 100, 150, 300) including one or more imagers or imager assemblies (50, 126/128, 177/178, 350) that capture two-dimensional images of an object disposed in a view volume (5), the data reader having fold mirrors (60/62, 122/124, 172/174/176, 362/360) and other component arrangement that enable compact and efficient component configuration.