Passive wireless probe, steaming oven and automatic cooking method

Abstract

The invention relates to a passive wireless probe, a steaming oven and an automatic cooking method. The passive wireless probe comprises the following components: a probe main body; the surface acoustic wave sensor is arranged in the probe main body, and the surface acoustic wave sensor comprises a piezoelectric substrate, an interdigital transducer arranged on the piezoelectric substrate and a pair of temperature measurement reflecting gratings which are arranged on the piezoelectric substrate and are positioned on two sides of the interdigital transducer; and the sensor antenna is connected to the interdigital transducer and is used for receiving a radio frequency signal and transmitting a feedback signal. According to the passive wireless probe, the antenna is adopted to transmit feedback signals, no metal wire is needed for connection, the potential safety hazard of wire aging existing in a traditional wired probe is avoided, the surface acoustic wave sensor is prepared through the high-temperature-resistant piezoelectric material, and the problem that a traditional wireless active food probe cannot resist high temperature is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of kitchen household appliances, and particularly to a passive wireless probe, a steam oven, and an automatic cooking method. Background Art

[0002] With the development of home appliance technology, more and more household appliances have entered people's homes. Among them, as a convenient and fast common household appliance, the steam oven is also increasingly favored by people. The steam oven can detect the temperature of the food during cooking through a snake dance probe and estimate whether the food is cooked according to the temperature.

[0003] At present, there are generally two types of food probes for steam ovens on the market. One is a wired temperature probe that provides the current and voltage required by the sensor through a wire connection, and then transmits the electrical signal that changes with temperature to the controller through the wire. Since the wired temperature probe needs to connect the temperature measuring element and the temperature measuring system through a metal wire and then transmit the signal, when the food is heated inside the oven, on the one hand, it is not easy to connect the metal wire; on the other hand, the insulating layer outside the wire is prone to aging in a high-temperature environment, and the insulating layer may fall off after long-term use, resulting in a decrease in the insulation level of the product and there are certain potential safety hazards; in addition, the wire passes through the sealed cavity, and the design of the connector is also more difficult. The other is a wireless active temperature probe that powers the sensor through a battery or an energy storage capacitor, and the electrical signal is transmitted to the controller through a wireless radio frequency signal (such as Bluetooth, WIFI, etc.). Although the wireless active probe can solve the wire connection problem, the battery, energy storage capacitor, temperature acquisition, and signal emission circuits inside the probe cannot withstand high temperatures. When the user operates improperly or during the baking process, if the probe is not in good contact with the food, a high temperature above 200°C will be generated, resulting in damage to the functional components of the probe. Summary of the Invention

[0004] Based on this, in view of the problems that the existing wired food probes currently need connection wires or the existing wireless probes are not resistant to high temperatures, it is necessary to provide a passive wireless probe, a steam oven, and an automatic cooking method.

[0005] On the one hand, the present application provides a passive wireless probe, including:

[0006] A passive wireless probe, including:

[0007] A probe body;

[0008] A surface acoustic wave sensor, the surface acoustic wave sensor is disposed in the probe body, the surface acoustic wave sensor includes a piezoelectric substrate, an interdigital transducer disposed on the piezoelectric substrate, and a pair of temperature measurement reflection gratings disposed on the piezoelectric substrate and on both sides of the interdigital transducer; and

[0009] A sensor antenna, which is connected to the interdigital transducer and is used for receiving radio frequency signals and transmitting feedback signals.

[0010] In one embodiment, the probe body includes an outer probe tube body, an inner probe tube body disposed inside the outer probe tube body, and an insulating layer disposed between the outer probe tube body and the inner probe tube body; the surface acoustic wave sensor further includes a pair of capacitive reflection gratings disposed on the piezoelectric substrate and respectively located on a side of the temperature measurement reflection grating away from the interdigital transducer, the capacitive reflection gratings are respectively electrically connected to the outer probe tube body and the inner probe tube body, and the frequency bandwidth range of the temperature measurement reflection grating is different from the frequency bandwidth range of the capacitive reflection grating.

[0011] In one embodiment, the surface acoustic wave sensor further includes a plurality of elastic contacts respectively electrically connected to the capacitive reflection gratings, and the elastic contacts are respectively clamped to the outer probe tube body and the inner probe tube body.

[0012] In one embodiment, the passive wireless probe further includes an antenna portion, the antenna portion is fixedly disposed at the rear end of the probe body, the antenna portion is provided with an antenna cavity, and the sensor antenna is disposed inside the antenna cavity.

[0013] In one embodiment, the surface acoustic wave sensor is disposed at the front end of the probe body, and a thermal conductive silicone grease is filled between the surface acoustic wave sensor and the probe body.

[0014] On the other hand, the present application provides a steam oven, including:

[0015] The passive wireless probe as described in any one of the above;

[0016] A cooking component, the cooking component has a cooking cavity, and the passive wireless probe is disposed inside the cooking cavity; and

[0017] A control component, the control component includes a control unit, a signal transmitting unit electrically connected to the control unit, a signal conditioning unit electrically connected to the control unit, a signal receiving unit electrically connected to the signal conditioning unit, a transceiver switch electrically connected to the signal transmitting unit and the signal receiving unit, and a control antenna electrically connected to the transceiver switch, and the control antenna can be communicatively connected to the sensor antenna of the passive wireless probe.

[0018] Further, the present application provides an automatic cooking method, including the steps of:

[0019] Put the food into the cooking cavity of the steam oven, and select the cooking recipe corresponding to the food for cooking;

[0020] Continuously detect the temperature change rate and humidity change rate of the food in the steam oven through a passive wireless probe;

[0021] Through the control component of the steam oven, change the cooking strategy according to the temperature change rate and humidity change rate of the food, so that the temperature change rate and humidity change rate of the food meet the cooking requirements of the cooking plan; and

[0022] Repeat the above steps until the temperature or humidity of the food reaches the maturity level required by the cooking plan.

[0023] In one embodiment, the step of continuously detecting the temperature change rate and humidity change rate of the food in the steam oven through a passive wireless probe includes the steps of:

[0024] Continuously transmit a temperature measurement radio frequency signal and a humidity measurement radio frequency signal from the control component of the steam oven to the sensor antenna of the passive wireless probe;

[0025] Through the sensor antenna, transmit the temperature measurement radio frequency signal and the humidity measurement radio frequency signal to the surface acoustic wave sensor of the passive wireless probe;

[0026] Through the surface acoustic wave sensor, convert the temperature measurement radio frequency signal and the humidity measurement radio frequency signal into a temperature feedback signal and a humidity feedback signal;

[0027] Through the sensor antenna, transmit the temperature feedback signal and the humidity feedback signal back to the control component; and

[0028] According to the temperature feedback signal and the humidity feedback signal, calculate the temperature change rate and humidity change rate of the food through the control component.

[0029] In one embodiment, the step of converting the temperature measurement radio frequency signal and the humidity measurement radio frequency signal into a temperature feedback signal and a humidity feedback signal through the surface acoustic wave sensor includes:

[0030] Through the interdigital transducer of the surface acoustic wave sensor, convert the temperature measurement radio frequency signal and the humidity measurement radio frequency signal into a temperature measurement surface acoustic wave and a humidity measurement surface acoustic wave propagating on the piezoelectric substrate of the surface acoustic wave sensor;

[0031] Through the temperature measurement reflection grating of the surface acoustic wave sensor, reflect the temperature measurement surface acoustic wave transmitted to the temperature measurement reflection grating, so that the reflected temperature measurement surface acoustic wave resonates with the temperature measurement surface acoustic wave signal that has not propagated to the temperature measurement reflection grating, forming a temperature measurement echo;

[0032] Through the capacitance reflection grating of the surface acoustic wave sensor, reflect the humidity measurement surface acoustic wave transmitted to the capacitance reflection grating, forming a humidity measurement echo; and

[0033] Through the interdigital transducer, the temperature measurement echo and the humidity measurement echo are converted into a temperature feedback signal and a humidity feedback signal.

[0034] In one embodiment, in the step of changing the cooking strategy according to the temperature change rate and the humidity change rate of the food by the control component of the steam oven, so that the temperature change rate and the humidity change rate of the food meet the cooking requirements of the cooking plan,

[0035] When the control component determines that the temperature change rate of the food is less than the minimum threshold of the temperature change rate required by the cooking plan, the control component cooks the food according to the first cooking strategy to increase the heating rate of the food; when the control component determines that the temperature change rate of the food is greater than the maximum threshold of the temperature change rate required by the cooking plan, the control component cooks the food according to the second cooking strategy to reduce the heating rate of the food; when the control component determines that the humidity change rate of the food is greater than the maximum threshold of the humidity change rate required by the cooking plan, the control component cooks the food according to the third cooking strategy to reduce the water loss rate of the food; when the control component determines that the humidity change rate of the food is less than the minimum threshold of the humidity change rate required by the cooking plan, the control component cooks the food according to the fourth cooking strategy to increase the water loss rate of the food.

[0036] In this application, by using an antenna to transmit the feedback signal, there is no need to use a metal wire connection, avoiding the safety hazard of wire aging existing in the traditional wired probe, and by preparing the surface acoustic wave sensor with a high-temperature resistant piezoelectric material, the problem of inability to withstand high temperatures existing in the traditional wireless active food probe is avoided.

[0037] The passive wireless probe of this application can not only detect the temperature of the food, but also detect the humidity of the food. By continuously transmitting the temperature measurement radio frequency signal and the humidity measurement radio frequency signal by the control component of the steam oven, a temperature feedback signal that changes continuously with temperature and a humidity feedback signal that changes with the moisture of the food can be obtained, and the temperature change situation and the humidity change situation of the food can be detected, more accurately reflecting the cooking situation of the food. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 is a schematic structural diagram of a passive wireless probe provided by an embodiment of this application;

[0039] Figure 2 shows a schematic structural diagram of the surface acoustic wave sensor of the passive wireless probe according to the above embodiment of this application;

[0040] Figure 3 As shown in Figure 1 is a partially enlarged schematic view of A of the passive wireless probe shown;

[0041] Figure 4Shows the relationship diagram of the frequency and amplitude of the temperature measurement echo of the surface acoustic wave sensor of the passive wireless probe according to the above embodiment of the present application;

[0042] Figure 5 Shows the relationship diagram of the time and amplitude of the temperature measurement echo and the test echo of the surface acoustic wave sensor of the passive wireless probe according to the above embodiment of the present application;

[0043] Figure 6 Shows the relationship diagram of the capacitance value and the amplitude of the test echo of the surface acoustic wave sensor of the passive wireless probe according to the above embodiment of the present application;

[0044] Figure 7 Shows the relationship diagram of the capacitance value and the phase of the test echo of the surface acoustic wave sensor of the passive wireless probe according to the above embodiment of the present application;

[0045] Figure 8 Schematic diagram of the control component of the steam oven provided by an embodiment of the present application;

[0046] Figure 9 Schematic diagram of the steps of the automatic cooking method provided by an embodiment of the present application;

[0047] Figure 10 Shows the schematic diagram of the steps of step S200 of the automatic cooking method according to the above embodiment of the present application;

[0048] Figure 11 Shows the schematic diagram of the steps of step S230 of the automatic cooking method according to the above embodiment of the present application;

[0049] Figure 12 Shows the schematic flow diagram of the automatic cooking method according to the above embodiment of the present application.

[0050] Reference numerals: 10, passive wireless probe; 11, probe body; 111, outer probe tube; 112, inner probe tube; 113, insulating layer; 12, surface acoustic wave sensor; 121, piezoelectric substrate; 122, interdigital transducer; 123, temperature measurement reflection grating; 124, capacitance reflection grating; 125, elastic contact; 13, sensor antenna; 14, antenna part; 141, antenna cavity; 15, thermal grease; 20, control component; 21, control unit; 22, signal transmitting unit; 23, signal conditioning unit; 24, signal receiving unit; 25, transceiver switch; 26, control antenna; 30, cooking component. Detailed Description

[0051] To make the above objects, features, and advantages of the present invention more apparent and understandable, the following describes the specific embodiments of the present invention in detail with reference to the accompanying drawings. Many specific details are set forth in the following description to facilitate a thorough understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the spirit of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0052] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. These are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0053] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, "a plurality" means at least two, such as two, three, etc., unless otherwise specifically and clearly defined.

[0054] In the present invention, unless otherwise clearly defined and limited, the terms "mounted", "connected", "coupled", "fixed", etc. should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal communication of two elements or the interaction relationship between two elements, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0055] In the present invention, unless otherwise clearly defined and limited, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over", and "on top of" the second feature may be that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "beneath", and "underneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.

[0056] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only implementation methods.

[0057] On the one hand, based on the problem that existing wired food probes require connecting wires or existing wireless probes are not resistant to high temperatures, the present application provides a passive wireless probe that realizes wireless passive temperature detection through radio frequency power supply and signal transmission.

[0058] For details, please refer to Figure 1 and Figure 2 The passive wireless probe 10 of the present application may include: a probe body 11, a surface acoustic wave sensor 12 and a sensor antenna 13, wherein the surface acoustic wave sensor 12 is arranged in the probe body 11, and the surface acoustic wave sensor 12 may include a piezoelectric substrate 121, an interdigital transducer 122 and a pair of temperature measuring reflective gratings 123. The piezoelectric substrate 121 may be made of a material having a piezoelectric effect such as quartz, lithium niobate, or barium titanate crystal, has the characteristics of high temperature resistance, and can convert electrical signals and mechanical waves into each other. The interdigital transducer 122 and the temperature measuring reflective grating 123 are both arranged on the piezoelectric substrate 121, and the temperature measuring reflective grating 123 is located on both sides of the interdigital transducer 122. The sensor antenna 13 is connected to the interdigital transducer 122 and can receive radio frequency signals and transmit feedback signals. The IDT 122 can convert the radio frequency signal received by the sensor antenna 13 into a surface acoustic wave signal propagating on the piezoelectric substrate 121, and can also convert the echo reflected back to the IDT 122 into a feedback signal. The temperature measuring reflective grating 123 can reflect the surface acoustic wave to form an echo.

[0059] It can be understood that this application uses an antenna to transmit feedback signals without the need for metal wire connections, thus avoiding the safety hazards of wire aging in traditional wired probes, and uses high-temperature resistant piezoelectric materials to prepare acoustic surface sensors, thus avoiding the problem of traditional wireless active food probes that cannot withstand high temperatures.

[0060] When the sensor antenna 13 receives the temperature measurement radio frequency signal sent by the control component 20 of the steam oven, the interdigital transducer 122 converts the temperature measurement radio frequency signal into a temperature measurement surface acoustic wave propagating on the piezoelectric substrate 121. When the temperature measurement surface acoustic wave propagates to the temperature measurement reflection grating 123, it is reflected back to the interdigital transducer 122 by the temperature measurement reflection grating 123. The temperature measurement surface acoustic wave reflected by the temperature measurement reflection grating 123 resonates with the temperature measurement surface acoustic wave that has not propagated to the temperature measurement reflection grating 123 to form a temperature measurement echo. The interdigital transducer 122 converts the temperature measurement echo into a temperature feedback signal and transmits it back to the control component 20 of the steam oven through the sensor antenna 13. Since the propagation speed or frequency of the surface acoustic wave changes with the physical properties of the piezoelectric substrate 121, and the physical properties of the piezoelectric substrate 121 are related to the ambient temperature, when the temperature of the food changes, the physical properties of the piezoelectric substrate 121 change, causing the transmission rate of the surface acoustic wave propagating on the piezoelectric substrate 121 to change, resulting in a change in the resonance frequency of the temperature measurement surface acoustic wave between the temperature measurement reflection grating 123 and the interdigital transducer 122, and a change in the position of the resonance point of the temperature measurement echo, that is, a change in the position of the maximum amplitude of the temperature feedback signal received by the control component 20. Thus, the control component 20 can calculate the temperature of the food based on the position of the maximum amplitude of the temperature feedback signal.

[0061] In addition, the existing food probes can only detect the temperature inside the food and cannot detect information such as the moisture inside the food. Just through the single dimension of temperature, the cooking situation of the food cannot be correctly reflected.

[0062] Therefore, as Figure 2 and Figure 3As shown, in some embodiments, the surface acoustic wave sensor 12 of the present application further includes a pair of capacitive reflection gratings 124. The capacitive reflection gratings 124 are disposed on the piezoelectric substrate 121, and the capacitive reflection gratings 124 are respectively located on one side of the temperature measurement reflection grating 123 away from the interdigital transducer 122. The probe body 11 may include an outer probe tube 111, an inner probe tube 112, and an insulating layer 113. The inner probe tube 112 is disposed inside the outer probe tube 111, and the insulating layer 113 is disposed between the outer probe tube 111 and the inner probe tube 112 to separate the outer probe tube 111 and the inner probe tube 112. The capacitive reflection gratings 124 are respectively electrically connected to the outer probe tube 111 and the inner probe tube 112, so that the outer probe tube 111 and the inner probe tube 112 serve as two poles of the capacitive reflection grating 124 respectively. The capacitive reflection grating 124 can also reflect surface acoustic waves to form echoes. By setting the frequency bandwidth range of the temperature measurement reflection grating 123 to be different from that of the capacitive reflection grating 124, the temperature measurement reflection grating 123 and the capacitive reflection grating 124 can reflect radio frequency signals with different frequency bandwidths. In this way, the passive wireless probe 10 of the present application can not only detect the temperature of food, but also detect the humidity of food, so as to more accurately reflect the cooking situation of food.

[0063] It can be understood that when the sensor antenna 13 receives the humidity measurement radio frequency signal sent by the control component 20 of the steam oven, the interdigital transducer 122 converts the humidity measurement radio frequency signal into a humidity measurement surface acoustic wave propagating on the piezoelectric substrate 121. Since the frequency bandwidth of the humidity measurement surface acoustic wave is not within the frequency bandwidth range of the temperature measurement reflection grating 123, the humidity measurement surface acoustic wave can pass through the temperature measurement reflection grating 123 and continue to propagate, and finally is reflected by the humidity measurement reflection grating to form a humidity measurement echo. The interdigital transducer 122 converts the humidity measurement echo into a humidity feedback signal and transmits it back to the control component 20 of the steam oven through the sensor antenna 13. Since the reflectivity of the capacitive reflection grating 124 is related to the capacitance value of the food, and the capacitance value of the food is related to the dielectric constant of the food, and the dielectric constant of the food changes with the change of moisture. When the moisture in the food changes, the reflectivity of the capacitive reflection grating 124 changes, so that the amplitude or phase of the humidity measurement echo changes, that is, the amplitude or phase of the humidity feedback signal received by the control component 20 also changes. Therefore, the control component 20 can calculate the humidity of the food according to the change of the amplitude or phase of the humidity feedback signal. As Figure 6 shown is a relationship diagram between the capacitance value of food and the amplitude of the humidity echo. As Figure 7 shown is a relationship diagram between the capacitance value of food and the phase of the humidity echo. It can be seen from the figure that as the capacitance value increases, the amplitude of the humidity feedback signal gradually increases, while the phase of the humidity feedback signal gradually decreases.

[0064] In this way, by continuously emitting temperature-measuring radio frequency signals and humidity-measuring radio frequency signals through the control component 20 of the steam oven, a temperature feedback signal that continuously changes with temperature and a humidity feedback signal that changes with the moisture content of the food can be obtained, and the temperature change and humidity change of the food can be detected, more accurately reflecting the cooking situation of the food.

[0065] In addition, as Figure 4 and Figure 5 shown, when the sensor antenna 13 simultaneously receives the temperature-measuring radio frequency signal and the humidity-measuring radio frequency signal, due to the resonance of the temperature echo, the amplitude of the temperature echo is much larger than that of the humidity-measuring temperature echo, and since the position of the temperature-measuring reflection grating 123 is closer to the interdigital transducer 122 than the position of the capacitance reflection grating 124, therefore, the control component 20 identifies the feedback signal with a later timing as the humidity feedback signal.

[0066] Optionally, in some embodiments, the frequency bandwidth range of the temperature-measuring reflection grating 123 is from 433.05 MHz to 434.79 MHz, and the frequency bandwidth range of the capacitance reflection grating 124 is from 902 MHz to 928 MHz.

[0067] Preferably, in some embodiments, the two temperature-measuring reflection gratings 123 of the present application are respectively symmetrically arranged on both sides of the interdigital transducer 122. With such an arrangement, by respectively and symmetrically arranging the temperature-measuring reflection grating 123 and the capacitance reflection grating 124, the resonance probability of the temperature-measuring surface acoustic wave can be increased, so as to more accurately obtain the position of the resonance point of the temperature-measuring echo.

[0068] Optionally, as Figure 3 shown, in some embodiments, the surface acoustic wave sensor 12 of the present application may further include a plurality of elastic contact pieces 125, the elastic contact pieces 125 are respectively electrically connected to the capacitance reflection grating 124, and the elastic contact pieces 125 are respectively clamped to the outer probe tube body 111 and the inner probe tube body 112. With such an arrangement, on the one hand, the capacitance reflection grating 124 and the probe tube body are connected and conducted through the elastic contact pieces 125, and on the other hand, the surface acoustic wave sensor 12 is fixed in the probe body 11 by using the elasticity of the elastic contact pieces urchin.

[0069] Preferably, the contact surface of the elastic contact piece 125 with the outer probe tube body 111 or the inner probe tube body 112 is a tubular long contact surface, which can effectively prevent water vapor from entering and also ensure the pulling strength.

[0070] Particularly, as Figure 1As shown, in some embodiments, the passive wireless probe 10 of the present application further includes an antenna portion 14, which is fixedly arranged at the rear end of the probe body 11. The antenna portion 14 is provided with an antenna cavity 141, and the sensor antenna 13 is arranged in the antenna cavity 141. With such an arrangement, the antenna portion 14 can be used as the holding position of the food probe and can also protect the sensor antenna 13 to avoid damaging the sensor antenna 13 during the use of the probe.

[0071] Optionally, as Figure 3 shown, in some embodiments, the surface acoustic wave sensor 12 of the present application is arranged at the front end of the probe body 11 to ensure that the acoustic wave sensor can contact the food, and a thermal conductive silicone grease 15 is filled between the surface acoustic wave sensor 12 and the probe body 11. Through the full heat conduction of the thermal conductive silicone grease 15, the surface acoustic wave sensor 12 can detect the temperature more accurately.

[0072] On the other hand, as Figure 8 shown, the present application also provides a steam oven, which may include any one of the passive wireless probes 10, a cooking component 30, and a control component 20 as described above. The cooking component 30 has a cooking cavity and can be used for cooking food. The passive wireless probe 10 is arranged in the cooking cavity to detect the temperature and humidity of the food in the cooking cavity. The control component 20 may include a control unit 21, a signal transmitting unit 22, a signal conditioning unit 23, a signal receiving unit 24, a transceiver switch 25, and a control antenna 26. The signal transmitting unit 22 is electrically connected to the control unit 21, the signal conditioning unit 23 is electrically connected to the control unit 21, the signal receiving unit 24 is electrically connected to the signal conditioning unit 23, the transceiver switch 25 is electrically connected to the signal transmitting unit 22 and the signal receiving unit 24, the control antenna 26 is electrically connected to the transceiver switch 25, and the control antenna 26 is communicatively connected to the sensor antenna 13 of the passive wireless probe 10.

[0073] It can be understood that the transceiver switch 25 is used to control the connection between the signal transmitting unit 22 and the signal receiving unit 24 and the control antenna 26. The signal transmitting unit 22 can receive the instruction of the control unit 21 and emit a radio frequency signal. The radio frequency signal is transmitted to the sensor antenna 13 of the passive wireless probe 10 through the control antenna 26, and is converted into a feedback signal through the passive wireless probe 10. The feedback signal is transmitted back to the control antenna 26 through the sensor antenna 13, received by the signal receiving unit 24, adjusted by the signal conditioning unit 23, and then transmitted to the control unit 21. The control unit 21 calculates the temperature or humidity information in the feedback signal. In this way, the steam oven of the present application can detect the temperature change and humidity change of the food and more accurately reflect the cooking situation of the food.

[0074] Furthermore, as Figure 9And Figure 12 As shown, the present application also provides an automatic cooking method, including the steps of:

[0075] S100. Put the food into the cooking cavity of the steam oven, and select the cooking program corresponding to the food for cooking;

[0076] S200. Continuously detect the temperature change rate and humidity change rate of the food in the steam oven through a passive wireless probe;

[0077] S300. Through the control component of the steam oven, change the cooking strategy according to the temperature change rate and humidity change rate of the food, so that the temperature change rate and humidity change rate of the food meet the cooking requirements of the cooking program; and

[0078] S400. Repeat the above steps until the temperature or humidity of the food reaches the maturity level required by the cooking program.

[0079] It can be understood that the dielectric constant of the food reflects the content of free water in the food and the ratio with bound water or protein. By repeating the above steps S200 and S300, according to the temperature and capacitance in the food detected by the probe, the heating rate and water loss rate of the food can be obtained. Combining with the requirements of the cooking program corresponding to the food, it is possible to make an intelligent judgment, automatically adjust the cooking strategy, cook the food, and make the food obtain the best flavor.

[0080] Furthermore, as Figure 10 shown, in some embodiments, the step S200 of continuously detecting the temperature change rate and humidity change rate of the food in the steam oven through a passive wireless probe includes the steps of:

[0081] S210. Continuously transmit temperature measurement radio frequency signals and humidity measurement radio frequency signals to the sensor antenna of the passive wireless probe through the control component of the steam oven;

[0082] S220. Transmit the temperature measurement radio frequency signal and humidity measurement radio frequency signal to the surface acoustic wave sensor of the passive wireless probe through the sensor antenna;

[0083] S230. Through the surface acoustic wave sensor, convert the temperature measurement radio frequency signal and humidity measurement radio frequency signal into a temperature feedback signal and a humidity feedback signal;

[0084] S240. Transmit the temperature feedback signal and humidity feedback signal back to the control component through the sensor antenna; and

[0085] S250. Calculate the temperature change rate and humidity change rate of the food through the control component according to the temperature feedback signal and humidity feedback signal.

[0086] In this way, through the above steps, by continuously transmitting to the surface acoustic wave sensor, temperature feedback signals that change with temperature and humidity feedback signals that change with food moisture are obtained, so that the temperature change and humidity change of the food can be detected, and the accurate cooking condition of the food can be obtained to control the component to adjust the food cooking strategy.

[0087] Further, as Figure 11 shown, in some embodiments, the step S230 of converting the temperature measurement radio frequency signal and the humidity measurement radio frequency signal into temperature feedback signals and humidity feedback signals through the surface acoustic wave sensor includes:

[0088] S231: Convert the temperature measurement radio frequency signal and the humidity measurement radio frequency signal into a temperature measurement surface acoustic wave and a humidity measurement surface acoustic wave propagating on the piezoelectric substrate of the surface acoustic wave sensor through the interdigital transducer of the surface acoustic wave sensor;

[0089] S232: Reflect the temperature measurement surface acoustic wave transmitted to the temperature measurement reflection grating through the temperature measurement reflection grating of the surface acoustic wave sensor, so that the reflected temperature measurement surface acoustic wave resonates with the temperature measurement surface acoustic wave signal that has not propagated to the temperature measurement reflection grating to form a temperature measurement echo;

[0090] S233: Reflect the humidity measurement surface acoustic wave transmitted to the capacitance reflection grating through the capacitance reflection grating of the surface acoustic wave sensor to form a humidity measurement echo; and

[0091] S234: Convert the temperature measurement echo and the humidity measurement echo into temperature feedback signals and humidity feedback signals through the interdigital transducer.

[0092] It can be understood that according to the above steps, the temperature measurement radio frequency signal is converted by the interdigital transducer into a temperature measurement surface acoustic wave propagating on the piezoelectric substrate, and then reflected by the temperature measurement reflection grating and resonates with the surface acoustic wave that has not propagated to the temperature measurement reflection grating to form a temperature measurement echo with a resonance point. Finally, it is converted by the interdigital transducer into a temperature feedback signal. The position of the resonance point of the temperature measurement echo, that is, the position of the maximum amplitude of the temperature feedback signal, reflects the temperature of the food. The humidity measurement radio frequency signal is converted by the interdigital transducer into a humidity measurement surface acoustic wave propagating on the piezoelectric substrate, and then reflected by the capacitance reflection grating to form a humidity measurement echo, and finally converted by the interdigital transducer into a humidity feedback signal. The amplitude or phase of the humidity measurement echo reflects the humidity of the food.

[0093] Further, as Figure 12 shown, in some embodiments, in the step of changing the cooking strategy according to the temperature change rate and humidity change rate of the food by the control component of the steam oven so that the temperature change rate and humidity change rate of the food meet the cooking requirements of the cooking plan,

[0094] When the control component determines that the temperature change rate of the food is less than the minimum threshold of the temperature change rate required by the cooking recipe, the control component cooks the food according to the first cooking strategy to increase the heating rate of the food; when the control component determines that the temperature change rate of the food is greater than the maximum threshold of the temperature change rate required by the cooking recipe, the control component cooks the food according to the second cooking strategy to decrease the heating rate of the food; when the control component determines that the humidity change rate of the food is greater than the maximum threshold of the humidity change rate required by the cooking recipe, the control component cooks the food according to the third cooking strategy to decrease the water loss rate of the food; when the control component determines that the humidity change rate of the food is less than the minimum threshold of the humidity change rate required by the cooking recipe, the control component cooks the food according to the fourth cooking strategy to increase the water loss rate of the food.

[0095] It can be understood that the first cooking strategy and the second cooking strategy are cooking strategies for adjusting the temperature change rate of the food. When the temperature change rate of the food is less than the minimum threshold of the temperature change rate required by the cooking recipe, the control component determines that the heating rate of the food is too slow. According to the first cooking strategy, the heating rate of the food can be increased by reducing the convection cycle and increasing the heating temperature, and the temperature change rate of the food can be adjusted within the range of the temperature change rate required by the cooking recipe; when the temperature change rate of the food is greater than the maximum threshold of the temperature change rate required by the cooking recipe, the control component determines that the heating rate of the food is too fast. According to the second cooking strategy, the cooling rate of the food can be increased by increasing the convection cycle and decreasing the heating temperature, and the temperature change rate of the food can be adjusted within the range of the temperature change rate required by the cooking recipe. The third cooking strategy and the fourth cooking strategy are cooking strategies for adjusting the humidity change rate of the food. When the humidity change rate of the food is greater than the maximum threshold of the humidity change rate required by the cooking recipe, the control component determines that the water loss rate of the food is too fast. According to the third cooking strategy, the water loss rate of the food can be decreased by reducing the air outlet and replenishing water, and the humidity change rate of the food can be adjusted within the range of the humidity change rate required by the cooking recipe; when the humidity change rate of the food is less than the minimum threshold of the humidity change rate required by the cooking recipe, the control component determines that the water loss rate of the food is too slow. According to the fourth cooking strategy, the water loss rate of the food can be increased by increasing the air outlet, and the humidity change rate of the food can be adjusted within the range of the humidity change rate required by the cooking recipe.

[0096] Exemplarily, for the cooking scheme of meat food, the temperature change rate is mainly considered. If the temperature change rate is too fast, the meat is likely to become tough. Therefore, when cooking, if the control component determines that the temperature change rate is too fast, cooking according to the second cooking strategy can caramelize the meat skin to lock in moisture and prevent the meat from becoming tough. For the cooking scheme of seafood and fish food, it is comprehensively judged based on the humidity change rate and the temperature change rate. If the humidity change rate and the temperature change rate of seafood and fish food are too fast, the meat is likely to become dry and hard. Therefore, when cooking, if the control component determines that the humidity change rate is too fast, cooking according to the third cooking strategy, and if the control component determines that the temperature change rate is too fast, cooking according to the second cooking strategy, to prevent the meat from becoming dry and hard. For starchy foods, the cooking scheme is comprehensively judged based on the temperature change rate and the humidity change rate. If the temperature change rate and the humidity change rate of starchy foods are too fast, starch gelatinization and retrogradation are likely to occur. Therefore, when cooking, if the control component determines that the temperature change rate is too fast, cooking according to the second cooking strategy, and if the control component determines that the humidity change rate is too fast, cooking according to the third cooking strategy, to prevent starch gelatinization and retrogradation.

[0097] Further, as Figure 12 shown, in some embodiments, in the step S400 of repeating the above steps until the temperature or humidity of the food reaches the maturity level required by the cooking scheme, the control component determines whether the food is mature according to the humidity of the food at the calibrated temperature. It can be understood that without the occurrence of material changes in the food (such as the non-loss of free water), the internal dielectric constant changes with the temperature change. For every 10°C increase in temperature, the node constant decreases by about 8% to 10%. When the temperature exceeds the calibrated temperature (such as 55°C), after protein denaturation or starch gelatinization, the dielectric constant increases again as the hydrogen bonds and intermolecular forces decrease. At this time, the dielectric constant reflects the change in food maturity. When the dielectric constant no longer changes or changes slowly, it represents that the food is mature. In this application, the humidity of the food is detected by detecting the capacitance of the food, and the change in the dielectric constant of the food can be judged by detecting the humidity of the food. Therefore, the automatic cooking method of this application can determine whether the food is mature according to the humidity of the food at the calibrated temperature, realizing automatic cooking.

[0098] Exemplarily, with 25°C as the reference, the dielectric constant of the food can be calculated according to the following formula:

[0099] ε’ corrected =ε’ measured ×[1 + 0.009×(T - 25)];

[0100] where, ε’ corrected is the actual dielectric constant, ε’ measured is the measured dielectric constant, and T is the measured temperature.

[0101] Each of the technical features described above for the embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0102] The above-described embodiments only express several implementation manners of the present invention. Their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several deformations and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention patent shall be subject to the appended claims.

Claims

1. A passive wireless probe, characterized in that, Comprising: A probe body; A surface acoustic wave sensor disposed within the probe body, the surface acoustic wave sensor including a piezoelectric substrate, interdigital transducers disposed on the piezoelectric substrate, and a pair of temperature measurement reflection gratings disposed on the piezoelectric substrate and on both sides of the interdigital transducers; And A sensor antenna connected to the interdigital transducers for receiving radio frequency signals and transmitting feedback signals.

2. The passive wireless probe according to claim 1, wherein The probe body includes an outer probe tube, an inner probe tube disposed within the outer probe tube, and an insulating layer disposed between the outer probe tube and the inner probe tube; the surface acoustic wave sensor further includes a pair of capacitance reflection gratings disposed on the piezoelectric substrate and on the side of the temperature measurement reflection gratings away from the interdigital transducers, the capacitance reflection gratings being electrically connected to the outer probe tube and the inner probe tube respectively, and the frequency bandwidth range of the temperature measurement reflection gratings being different from the frequency bandwidth range of the capacitance reflection gratings.

3. The passive wireless probe according to claim 2, wherein The surface acoustic wave sensor further includes a plurality of elastic contact pieces electrically connected to the capacitance reflection gratings respectively, the elastic contact pieces being snap-connected to the outer probe tube and the inner probe tube respectively.

4. The passive wireless probe according to claim 2, characterized in that The passive wireless probe further includes an antenna portion fixedly provided at the rear end of the probe body, the antenna portion having an antenna cavity, and the sensor antenna is disposed within the antenna cavity.

5. The passive wireless probe according to claim 1, characterized in that, The surface acoustic wave sensor is disposed at the front end of the probe body, and a thermal conductive silicone grease is filled between the surface acoustic wave sensor and the probe body.

6. A steam oven, characterized in that, Comprising: The passive wireless probe according to any one of claims 1 to 5; A cooking assembly having a cooking cavity, the passive wireless probe being disposed within the cooking cavity; And A control assembly including a control unit, a signal transmitting unit electrically connected to the control unit, a signal conditioning unit electrically connected to the control unit, a signal receiving unit electrically connected to the signal conditioning unit, a transceiver switch electrically connected to the signal transmitting unit and the signal receiving unit, and a control antenna electrically connected to the transceiver switch, the control antenna being communicatively connected to the sensor antenna of the passive wireless probe.

7. An automatic cooking method, characterized in that, Including the steps of: Placing food into the cooking cavity of a steam oven and selecting a cooking recipe corresponding to the food for cooking; Continuously detecting the temperature change rate and humidity change rate of the food in the steam oven through the passive wireless probe; Changing the cooking strategy according to the temperature change rate and humidity change rate of the food through the control assembly of the steam oven so that the temperature change rate and humidity change rate of the food meet the cooking requirements of the cooking recipe; And Repeating the above steps until the temperature or humidity of the food reaches the maturity level required by the cooking recipe.

8. The automatic cooking method according to claim 7, wherein The step of continuously detecting the temperature change rate and humidity change rate of the food in the steam oven through the passive wireless probe includes the steps of: Continuously transmitting a temperature measurement radio frequency signal and a humidity measurement radio frequency signal from the control assembly of the steam oven to the sensor antenna of the passive wireless probe; Transmitting the temperature measurement radio frequency signal and the humidity measurement radio frequency signal to the surface acoustic wave sensor of the passive wireless probe through the sensor antenna; Through the surface acoustic wave sensor, the temperature measurement radio frequency signal and the humidity measurement radio frequency signal are converted into a temperature feedback signal and a humidity feedback signal; Through the sensor antenna, the temperature feedback signal and the humidity feedback signal are transmitted and fed back to the control component; and According to the temperature feedback signal and the humidity feedback signal, the control component calculates the temperature change rate and the humidity change rate of the food.

9. The automatic cooking method according to claim 8, characterized in that, The step of converting the temperature measurement radio frequency signal and the humidity measurement radio frequency signal into a temperature feedback signal and a humidity feedback signal through the surface acoustic wave sensor includes: Through the interdigital transducer of the surface acoustic wave sensor, the temperature measurement radio frequency signal and the humidity measurement radio frequency signal are converted into a temperature measurement surface acoustic wave and a humidity measurement surface acoustic wave propagating on the piezoelectric substrate of the surface acoustic wave sensor; Through the temperature measurement reflection grating of the surface acoustic wave sensor, the temperature measurement surface acoustic wave transmitted to the temperature measurement reflection grating is reflected, so that the reflected temperature measurement surface acoustic wave resonates with the temperature measurement surface acoustic wave signal that has not propagated to the temperature measurement reflection grating, forming a temperature measurement echo; Through the capacitive reflection grating of the surface acoustic wave sensor, the humidity measurement surface acoustic wave transmitted to the capacitive reflection grating is reflected to form a humidity measurement echo; and Through the interdigital transducer, the temperature measurement echo and the humidity measurement echo are converted into a temperature feedback signal and a humidity feedback signal.

10. The automatic cooking method according to claim 7, characterized in that, In the step of changing the cooking strategy according to the temperature change rate and the humidity change rate of the food by the control component of the steam oven so that the temperature change rate and the humidity change rate of the food meet the cooking requirements of the cooking plan, When the control component determines that the temperature change rate of the food is less than the minimum threshold of the temperature change rate required by the cooking plan, the control component cooks the food according to the first cooking strategy to increase the heating rate of the food; when the control component determines that the temperature change rate of the food is greater than the maximum threshold of the temperature change rate required by the cooking plan, the control component cooks the food according to the second cooking strategy to reduce the heating rate of the food; when the control component determines that the humidity change rate of the food is greater than the maximum threshold of the humidity change rate required by the cooking plan, the control component cooks the food according to the third cooking strategy to reduce the water loss rate of the food; when the control component determines that the humidity change rate of the food is less than the minimum threshold of the humidity change rate required by the cooking plan, the control component cooks the food according to the fourth cooking strategy to increase the water loss rate of the food.

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