Optical Rotary Knob Position Sensing for Domestic Appliances
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Solution Overview
Problem
Existing household appliance control devices face challenges in achieving precise position detection of rotatable operating elements due to high costs and detection tolerance, limiting precise setting of operating conditions.
Innovation Solution
An optically operating transmitter/receiver device is integrated into the control device, utilizing a structured floor on the control element with distinct color and surface roughness segments for precise position detection, combined with a metallic surface and light-transmitting filling compound for enhanced precision and wear-free operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If magnetic or electromagnetic sensors are used for position detection, then the operating device can detect the position of the operating element, but the cost increases and detection precision is limited due to detection tolerance
Solution Approach 1:
The patent replaces magnetic or electromagnetic sensors with an optical detection system. The evaluation device detects the rotary position of the operating element optically, eliminating the need for expensive magnetic or electromagnetic sensors while achieving higher detection precision without tolerance issues.
Solution Approach 2:
The patent uses color-coded identification elements (first color for cooking zone selection, second color for cooking level setting) that are detected by the optical evaluation device. This color-based encoding system enables precise position detection through optical means, avoiding the tolerance limitations of magnetic sensors.
2Measurement precision
If the operating element has a structured floor for optical detection, then position detection precision improves, but the manufacturing complexity increases
Solution Approach 1:
The patent applies color coatings or color-changing materials to specific regions of the operating element's bottom surface. These colored regions serve as identification elements that are easily detectable by the optical evaluation device, providing precise position detection while maintaining relatively simple manufacturing processes through conventional coloring techniques.
3Ease of repair
If the control element is made removable and reattachable for easy cleaning, then ease of maintenance improves, but the reliability of position detection may be affected
Solution Approach 1:
The patent designs the operating element to be removable and reattachable, allowing users to easily clean the control element itself. The optical detection system detects features on the bottom surface of the operating element, which remains intact during removal and reattachment, ensuring detection reliability is maintained while enabling easy cleaning of the visible surfaces.
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 enables cost-effective, precise, and reliable position detection of the control element, reducing detection tolerance and allowing for easy cleaning and maintenance, while maintaining a high-quality aesthetic appearance.
Implementation Method 1
an optically operating transmitter/receiver device with which the relative position of the operating element can be detected
Data Source
AI summary
The device has an operating element (10) rotatably arranged on an operating element retainer (9). The operating element adjusts operating conditions of a household appliance based on a relative position of the operating element to the retainer. An optically working transmitting/receiving device (15) is arranged on a structured base (17) of the operating element, and detects the relative position of the operating element. Structure regions i.e. cake-like circular segments, of the base are functionally associated to an operating condition. Plastic is filled in an opening (16) of a pedestal (12). An independent claim is also included for a household appliance.