Code Reader Light Window Layout for High-Speed Image Decoding
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Solution Overview
Problem
Existing code readers struggle to capture clear images of codes on moving workpieces at high speeds due to reduced exposure time, leading to insufficient brightness for decoding processing.
Innovation Solution
A code reader design with a Scheimpflug optical system and an illumination section positioned adjacent to the light receiving window, ensuring bright illumination and efficient image capture, utilizing a housing with a light receiving window that intersects the focal plane and includes features like near and far illumination sections and a heat dissipation system to maintain image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the moving speed of the workpiece is increased, then productivity is improved, but the exposure time is shortened resulting in insufficient image brightness
Solution Approach 1:
The patent applies a Scheimpflug optical system where the image plane is inclined relative to the optical axis, creating a tilted focal plane that extends in the conveyance direction. This dimensional arrangement allows the depth of field to cover a longer distance along the workpiece conveyance path, enabling sufficient light accumulation even at high speeds.
Solution Approach 2:
The patent changes the geometric parameters of the optical system by inclining the image plane at a specific angle (e.g., 45 degrees) relative to the optical axis. This parameter change transforms the focal plane orientation to match the conveyance direction, allowing the imaging unit to capture bright images of high-speed moving workpieces.
2Illumination intensity
If the exposure time is extended to improve image brightness, then illumination intensity is improved, but the moving speed of the workpiece must be reduced
Solution Approach 1:
By tilting the image plane to extend along the conveyance direction, the system creates a depth of field that spans a longer physical distance. This allows the imaging unit to capture sufficient light information from high-speed moving workpieces without requiring extended exposure time, thus maintaining productivity.
3Device complexity
If the illumination section is positioned far from the light receiving window, then device complexity is reduced, but the visual field range becomes insufficiently illuminated
Solution Approach 1:
The illumination section is positioned adjacent to the light receiving window, merging the illumination function with the imaging function in close proximity. This arrangement ensures that the illumination optical axis and the imaging optical axis are close to each other, providing uniform and sufficient illumination across the entire visual field range.
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
The design enables high-speed decoding by capturing images with sufficient brightness, reducing heat generation, and preventing stray light interference, thus enhancing decoding efficiency.
Implementation Method 1
an imaging unit that includes a Scheimpflug optical system including a lens for condensing reflected light from a code attached to a workpiece and an image sensor having a light receiving surface inclined with respect to an optical axis of the lens
Implementation Method 2
an imaging unit that includes a Scheimpflug optical system including a lens for condensing reflected light from a code attached to a workpiece and an image sensor having a light receiving surface inclined with respect to an optical axis of the lens, and that generates and outputs an image based on an amount of light received by the light receiving surface
Implementation Method 3
an illumination section that irradiates a workpiece with illumination light
Implementation Method 4
a housing that stores the illumination section, the imaging unit, and the control unit, and has a light receiving window for transmitting the reflected light to an inside
Data Source
AI summary
A code reader includes an illumination section, an imaging unit having a Scheimpflug optical system, a control unit that executes decoding processing on the code attached to a workpiece based on an image output from the imaging unit, and a housing that stores the illumination section, the imaging unit, and the control unit and has a light receiving window. The light receiving window is provided on the first side surface of the housing, and has a short side extending in a lateral direction and a long side, longer than the short side, extending in a longitudinal direction. A plane formed by the light receiving window intersects a plane formed by the focal plane of the Scheimpflug optical system. The illumination section is disposed adjacent to the light receiving window in the lateral direction of the light receiving window.