Rotatable Lens Array for Human Body Location Detection
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Solution Overview
Problem
Conventional pyroelectric infrared sensors installed on image forming apparatuses struggle to accurately detect the location and movement of a human body approaching or using the device, as they rely on temperature changes which are often too small and inconsistent, making it difficult to determine the direction of the human body and whether it is pausing or moving.
Innovation Solution
A human body sensing device equipped with a rotatable group of lenses around an infrared sensor, which generates alternating sensing zones and non-sensing zones, uses a rotary drive and rotation position sensor to recognize the location and movement of a human body based on infrared energy changes, allowing for more accurate detection by varying the sensing distance and rotation speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a pyroelectric infrared sensor is installed on the image forming apparatus, then the device can detect human bodies, but it cannot accurately identify the location and movement direction of the human body
Solution Approach 1:
The sensing system is segmented into multiple functional zones by introducing a rotatable shield plate with partition patterns. This divides the sensing area into distinct regions (first sensing zone, second sensing zone, third sensing zone) that can independently detect human body presence and movement direction, thereby improving location identification precision without requiring a completely new sensing technology.
Solution Approach 2:
The shield plate is made rotatable about the sensor axis, transforming a static sensing system into a dynamic one. By rotating the shield plate at different speeds and directions, the system can actively probe different spatial zones and determine movement direction based on temporal changes in sensor output, enabling accurate location and movement detection while maintaining relatively simple hardware.
2Adaptability or versatility
If the shield plate rotates at high speed, then the sensing coverage is improved, but the detection accuracy for movement direction decreases
Solution Approach 1:
The shield plate rotates periodically at multiple different speeds (first rotation speed for high-speed coverage, second rotation speed for accurate detection). This periodic action allows the system to alternately expand sensing coverage and maintain detection precision, with the control unit selecting appropriate rotation speeds based on the specific detection task requirements.
Solution Approach 2:
The rotation speed parameter of the shield plate is changed dynamically between at least two different values (first rotation speed and second rotation speed). By adjusting this key parameter, the system can adapt to different detection scenarios - using high speed for broad coverage and low speed for precise movement direction identification when needed.
3Measurement precision
If the shield plate rotates at low speed, then the movement direction detection accuracy is improved, but the sensing coverage and response speed decrease
Solution Approach 1:
The system employs periodic rotation of the shield plate at multiple speeds, using faster rotation cycles to maintain broad sensing coverage and rapid response, while incorporating slower rotation phases to ensure accurate movement direction detection. This periodic variation in action speed balances productivity and measurement precision.
Solution Approach 2:
The rotation speed parameter is dynamically adjusted based on detection needs. The control unit switches between first rotation speed (higher) for rapid response and broad coverage, and second rotation speed (lower) for precise movement direction detection, thereby optimizing the balance between productivity and measurement precision in different operational contexts.
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 enables the image forming apparatus to accurately identify the location and movement of a human body, effectively transitioning between sleep and normal operation modes, ensuring timely activation when a user approaches.
Implementation Method 1
an infrared sensor which detects a human body based on a change in infrared energy
Implementation Method 2
a pyroelectric infrared sensor with an energy-saving and low-cost configuration, capable of performing human body sensing
Data Source
AI summary
A human body sensing device comprises: an infrared sensor which detects a human body; a rotatable group of lenses having a plurality of lenses arranged around the sensor, the lenses being configured to: generate unit sensing zones defined by a sensing distance extending radially outwardly from the group and a small width extending in a rotation direction of the group; and form a plurality of alternating layers of a regional sensing zone including one or more than one of the unit sensing zones and a non-sensing zone not including any of the unit sensing zones, in a rotation direction of the group; a rotary drive which rotates the group; a rotation position sensor which detects a rotation position of the group; and a recognizer which recognizes the location and/or movement of a human body based on the output level indicated by the infrared sensor and the rotation position.