Barcode Reader Transflective Mirror Parallax Elimination
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Solution Overview
Problem
Typical barcode readers face issues with parallax due to the misalignment of image sensors and illumination sources, requiring multiple illumination sources to direct light in different directions, which complicates alignment and calibration.
Innovation Solution
The use of a transflective mirror within the barcode reader housing allows the field-of-view of the image sensor and the illumination pattern to be directed coaxially along parallel central axes, eliminating parallax and the need for multiple illumination sources by switching between transmissive and reflective states to control light passage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the image sensor and illumination source are aligned with different lines of sight to direct fields-of-view out of a common window, then the fields-of-view can be directed out of the common window, but parallax occurs causing displacement in the apparent position of the illumination pattern
Solution Approach 1:
A beam splitter is introduced as an intermediary optical element between the illumination source and the common window. The beam splitter divides the illumination light into two separate paths: one path directs illumination along a first line of sight, and another path directs illumination along a second line of sight that is coaxial with the image sensor. This mediator enables the illumination source to provide illumination in multiple directions simultaneously without causing parallax, as the beam splitter precisely controls the light distribution to maintain proper alignment relationships.
2Adaptability or versatility
If multiple illumination sources are used to provide illumination in different directions, then illumination coverage is improved, but device complexity and alignment difficulty increase
Solution Approach 1:
A single illumination source is designed to perform multiple functions by directing illumination along different lines of sight through optical elements such as a beam splitter. The illumination source serves both to provide on-axis illumination (coaxial with the image sensor) and off-axis illumination (at an angle to the image sensor) simultaneously, eliminating the need for multiple separate illumination sources while maintaining comprehensive illumination coverage and reducing device complexity.
3Adaptability or versatility
If multiple illumination sources are used to direct light in different directions, then illumination coverage is improved, but alignment and calibration become more difficult
Solution Approach 1:
A beam splitter serves as a precision optical intermediary that simplifies alignment by providing fixed, pre-determined light paths. Instead of independently aligning multiple illumination sources, the beam splitter automatically divides the single illumination source's output into properly oriented beams, with the optical element's geometry determining the exact angles and directions. This eliminates complex multi-source alignment procedures and reduces calibration difficulty while maintaining the ability to provide illumination in multiple directions.
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 ensures zero parallax, simplifies alignment, eliminates the need for calibration, and allows for both on-axis and off-axis illumination from a single illumination source, enhancing the accuracy and usability of the barcode reader.
Implementation Method 1
the first transflective mirror is positioned in a path of the field-of-view of the imaging sensor. The field-of-view of the imaging sensor passes through the first transflective mirror and out the window with the first transflective mirror in a transmissive state and the illumination pattern from the illumination source is reflected off of the first transflective mirror and out the window with the first transflective mirror in a reflective state.
Implementation Method 2
a first transflective mirror positioned within the housing... with the first transflective mirror in a transmissive state and the illumination pattern from the illumination source is reflected off of the first transflective mirror and out the window with the first transflective mirror in a reflective state
Data Source
AI summary
Barcode readers with transflective mirrors are disclosed herein. An example barcode reader includes a housing and a window positioned within the housing, an imaging sensor and an illumination source positioned within the housing, and a transflective mirror positioned within the housing. The field-of-view of the imaging sensor is directed through the window along a first central axis of the field-of-view of the imaging sensor and the illumination pattern from the illumination source is directed through the window along a second central axis of the illumination pattern that is substantially parallel to the first central axis of the field-of-view of the imaging sensor.