Aperture Stop Blocks Virtual Hot Spots in Object Sensors
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Solution Overview
Problem
Existing electro-optical readers face issues with energy wastage and performance degradation due to continuous flashing of bright light, hot spots caused by reflected infrared light, and glare that overload and saturate object sensors, compromising reading accuracy and user experience.
Innovation Solution
The implementation of an object sensing system with a uniquely configured optical element, such as an aperture stop, in the object detection path to block virtual hot spots and prevent glare from reaching the object sensor, combined with strategically placed IR LEDs and sensors to enhance object detection efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If continuous flashing of bright light from LEDs or laser is used for illumination, then reading capability is maintained, but energy is wasted and component lifetimes degrade
Solution Approach 1:
The patent implements periodic illumination by controlling the LED or laser to flash only during specific time windows when object detection is required, rather than continuous operation. The controller activates illumination briefly before and during object detection phases, significantly reducing energy consumption while maintaining reading capability through timely light availability.
2Reliability
If continuous flashing of bright light is used, then reading capability is maintained, but component lifetimes degrade
Solution Approach 1:
The patent reduces component lifetime degradation by implementing periodic illumination control, where the LED or laser operates only during necessary detection windows rather than continuously. This extends the operational lifespan of illumination components while preserving reading functionality through strategically timed activation.
3Difficulty of detecting and measuring
If infrared light is used for object sensing, then object detection is enabled, but reflected infrared light creates hot spots that degrade sensor performance
Solution Approach 1:
The patent extracts and eliminates the harmful reflected infrared light by introducing an optical element (such as a beam splitter or directional mirror) that directs the infrared illumination path away from the object sensor's field of view. This separates the infrared detection function from the reflected light interference, allowing object sensing while preventing hot spot formation on the sensor.
Solution Approach 2:
The patent introduces an intermediary optical element between the infrared light source and the object sensor that mediates the interaction by directing infrared light along a path that does not create hot spots on the sensor. This intermediary component enables infrared object detection while blocking the harmful reflected light from reaching the sensor directly.
4Loss of energy
If the scan engine is activated with low duty cycle to reduce energy consumption, then energy is saved, but reading performance becomes sluggish
Solution Approach 1:
The patent implements a feedback mechanism where the object sensor continuously monitors the detection field of view and provides feedback to the controller. When an object is detected, the controller activates the scan engine for reading. This feedback-driven activation ensures the scan engine operates only when needed, balancing energy consumption with reading speed by avoiding unnecessary scanning while maintaining rapid response to objects.
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 energy consumption, minimizes performance delays, and improves reading accuracy by eliminating hot spots and glare, leading to enhanced user experience and efficient target detection.
Implementation Method 1
the object light source includes a pair of infrared (IR) light emitting diodes (LEDs), and the object light sensor is an IR light sensor
Implementation Method 2
an object light sensor for detecting return object sensing light returned from the object along an object detection path through the window
Implementation Method 3
a reading light source for directing reading light through the window at a target for return therefrom during reading
Implementation Method 4
a reading light detector for detecting return reading light from the target along a reading path through the window over a reading field of view during reading
Implementation Method 5
The implementation of an object sensing system with a uniquely configured optical element, such as an aperture stop, in the object detection path to block virtual hot spots and prevent glare from reaching the object sensor
Data Source
AI summary
A workstation for electro-optically reading targets in a reading field of view includes an object sensing system that senses an object entering the workstation by directing object sensing light through a window at the object, and detecting return object sensing light returned from the object along an object detection path through the window over an object detection field of view of an object light sensor. A portion of the object sensing light incident on the window is reflected therefrom into the object detection field of view as a virtual hot spot that degrades object sensor performance. An optical element, e.g., an aperture stop, in the object detection path optically modifies the object detection field of view to prevent the virtual hot spot from being detected by the object light sensor.