Induction Cooker Infrared Sensor Ambient Light Filtering
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Solution Overview
Problem
Conventional induction heating cookers face challenges in accurately sensing infrared sensor abnormalities, especially in high luminance environments where ambient light affects the sensor's output, leading to potential failures in detecting sensor issues before heating begins.
Innovation Solution
The induction heating cooker incorporates a visible light cutting filter on the printed circuit board to block ambient visible light while allowing infrared radiation to reach the infrared sensor, and a sensor failure sensing-purpose light emitting portion that emits visible light to detect sensor failures without increasing the visible light emission, ensuring accurate abnormality sensing without user visual recognition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a visible light cutting filter is provided around the infrared sensor to block ambient visible light, then the infrared sensor output is protected from ambient light interference, but the light from the light emitting portion cannot reach the infrared sensor for abnormality sensing
Solution Approach 1:
The patent divides the optical filtering function into two separate components: a visible light cutting filter to block ambient light, and a light emitting portion to provide test light for sensor abnormality detection. This segmentation allows each component to perform its specific function without interfering with the other, resolving the contradiction between protecting sensor accuracy and enabling reliability testing
Solution Approach 2:
The patent introduces a light emitting portion as an intermediary device that provides test light to the infrared sensor through the visible light cutting filter. This intermediary enables the sensor to be tested for abnormalities while the filter remains in place to block ambient light, thus maintaining both measurement precision and reliability detection capability
2Reliability
If the light emitting portion emits visible light for sensor failure sensing, then sensor abnormalities can be detected, but the visible light may be visually recognized by users causing discomfort
Solution Approach 1:
The patent applies local quality by making the light emitting portion invisible to human eyes while maintaining its functionality for sensor detection. The light emitted has specific characteristics (likely infrared or specific wavelength) that are detectable by the infrared sensor but not visible to users, thus providing local quality differentiation between sensor interaction and human perception
Solution Approach 2:
The patent utilizes color/wavelength changes by emitting light at a wavelength that is invisible to the human eye (such as infrared) but detectable by the infrared sensor. This wavelength selection resolves the contradiction by making the detection light imperceptible to users while maintaining its utility for sensor failure sensing
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 suppresses the impact of ambient light on the infrared sensor, allowing for accurate detection of sensor failures even in bright environments, reducing the need for increased light emission and maintaining user-friendly design by hiding the light from the sensor failure detection mechanism.
Implementation Method 1
a visible light cutting filter provided on a surface of the printed circuit board where the infrared sensor is held, so as to cover a field of view of the infrared sensor, the visible light cutting filter allowing transmission of the infrared radiation externally incident upon the infrared sensor and cutting off visible light externally incident upon the infrared sensor
Implementation Method 2
an infrared sensor that is provided below the top plate and that senses infrared radiation radiated from the heating-target object
Implementation Method 3
a sensor failure sensing-purpose light emitting portion that emits visible light for sensing a failure of the infrared sensor
Implementation Method 4
a heating coil that heats a heating-target object on a top plate
Implementation Method 5
an induction heating cooker which inductively heats a cooking vessel with a heating coil
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
The present invention provides an induction heating cooker, which is structured to cut off visible light being incident upon an infrared sensor, yet being capable of more accurately sensing any abnormality of the infrared sensor before heating is started. To this end, the induction heating cooker includes: a sensor failure sensing-purpose light emitting portion 7 that emits visible light for sensing any failure of an infrared sensor 5; a visible light cutting filter 6 provided on a surface of a printed circuit board 5 holding the infrared sensor 5 so as to cover the field of view of the infrared sensor 4; and a control unit 11 that limits the output of an inverter circuit 10 supplying a high-frequency current to a heating coil 3 when the output of the infrared sensor 5 is equal to or less than a threshold value in a situation where the sensor failure sensing-purpose light emitting portion 7 is lit up. The infrared sensor 5 receives the visible light from the sensor failure sensing-purpose light emitting portion 7 to irradiate inside the visible light cutting filter 6.