IR Proximity Sensor Zone Definition for POS Workstations
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Solution Overview
Problem
Existing point-of-transaction workstations face issues with false triggering of electro-optical reading due to the inability to distinguish between infrared light reflected from products and individuals, leading to incorrect detection of targets outside or inside the selected zone, especially with varying platform lengths and sensitive proximity systems.
Innovation Solution
The implementation of an adjustable infrared (IR) emission and detection field system with inclined axes and a controller-activated illumination system that only illuminates and captures images of targets within a well-defined selected zone, using IR LEDs and a field stop or wedge prism to ensure accurate detection and reduce false triggering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the proximity system uses high sensitivity to detect products in the far field, then detection capability is improved, but false triggering by individuals or items outside the selected zone increases
Solution Approach 1:
The detection space is segmented into a selected zone and regions outside it using optical field definition. The IR emitter and sensor are configured with specific emission and detection fields that intersect only within the selected zone, creating spatial segmentation that allows high sensitivity detection without false triggering from outside areas.
Solution Approach 2:
The patent introduces an intermediary spatial boundary defined by the intersection of IR emission and detection fields. This intermediary zone acts as a gatekeeper, allowing only light from within the selected zone to trigger detection, while blocking or excluding light from outside sources even when sensitivity is high.
2Reliability
If the IR emitter output power is reduced to avoid false triggering, then false triggering is reduced, but detection sensitivity in the far field deteriorates
Solution Approach 1:
The patent applies local quality by concentrating the IR emission and detection energy specifically within the selected zone rather than uniformly in all directions. The optical fields are configured to create a localized detection region, allowing high emitter power to be used without causing false triggering outside the zone, as the energy is spatially concentrated where needed.
3Adaptability or versatility
If the workstation uses a long triggering volume to accommodate long platforms, then adaptability to different platform lengths is improved, but false triggering by items or persons outside the selected zone increases
Solution Approach 1:
The patent implements dynamic adaptability through the adjustable field stop or wedge prism that can modify the IR detection field geometry. This dynamic adjustment capability allows the system to accommodate different platform lengths while maintaining a well-defined selected zone, as the field configuration can be changed without expanding the false triggering vulnerability.
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 effectively reduces false triggering by ensuring that only targets within the selected zone are illuminated and read, accommodating both long and short platforms, and maintaining sensitivity for detecting products at various distances without reducing IR emitter output power.
Implementation Method 1
The proximity system has an infrared (IR) emitter for emitting IR light into an IR emission field
Implementation Method 2
an IR sensor for sensing return IR light within an IR detection field that intersects the IR emission field in the selected zone
Implementation Method 3
an energizable illumination system supported by the housing and operative for illuminating the field of view with illumination light over an illumination field
Implementation Method 4
a solid-state imager supported by the housing and having an array of image sensors looking at a field of view that extends through the window to a target to be imaged
Data Source
AI summary
Products associated with targets to be read by image capture are processed in a workstation having a window, a solid-state imager looking at a field of view extending through the window to a target to be imaged, and an illumination system for illuminating the field of view. A proximity system detects a product associated with the target in a selected zone outside the window. The proximity system has an infrared (IR) emitter for emitting IR light into an IR emission field, and an IR sensor for sensing return IR light within an IR detection field that intersects the IR emission field in the selected zone. A controller energizes the illumination system in response to the detection of the product in the selected zone, and processes return illumination light captured in the field of view by the imager.