Temperature sensing device

Abstract

The invention discloses a temperature sensing device. The temperature sensing device comprises a thermopile sensing assembly with a metal mesh sleeve so as to prevent microwaves from entering a thermopile sensor to affect temperature measurement. The device comprises more than one thermopile sensing assembly, an environment temperature sensor, a signal processing dedicated chip and an infrared lens providing a narrow field angle. When the double thermopile sensing assembly is used, one unit is an active unit which has a narrow field angle and is used for sensing the temperature of an object to be measured, and the other unit is a dummy unit which is used for compensating the packaging shell effect caused by sharp rise of the environment temperature during heating so as to provide accurate temperature measurement. The invention also provides a visible light source to irradiate the sensing range of the thermopile sensor, so that a user can place the object to be heated conveniently, and the field angle of the light source is the same as the field angle of the thermopile sensor.

Description

Technical Field

[0001] The invention relates to a temperature sensing device, in particular to a temperature sensing device with a non-contact temperature sensor, a thermopile sensor, an anti-microwave interference, and a narrow field of view thermal sensor. Background Art

[0002] Smart appliances such as microwave ovens require a non-contact temperature sensor to monitor the surface temperature of food to control the microwave's heating power and duration.

[0003] Traditionally, single-point thermopile sensors are used for non-contact temperature measurement, but their field of view is very large (e.g., 70-110 degrees). In the application of heating food in a microwave oven, the distance between the thermopile sensor and the food on the turntable is about 25 cm, so what is measured is the sum of the temperature of the object to be measured and the ambient temperature, so the surface temperature of the object to be measured cannot be truly measured. Therefore, when using a single thermopile sensor to measure the surface temperature of food to be heated in a microwave oven, the field of view of the thermopile sensor should be small (e.g., 5-15 degrees), so that the surface temperature of the food to be measured can be accurately measured, rather than the average temperature of the food and the ambient temperature.

[0004] In the case of microwave ovens, during microwave heating, part of the penetrating microwaves will be absorbed by the thermopile sensor, causing measurement errors. There is a practical need to accurately measure the temperature of the object being measured without stopping microwave heating.

[0005] In addition, the field of view of the thermopile sensor is small. If a visible light source can be used to display the sensing temperature area of ​​the thermopile sensor, it will be convenient for users to place the object to be heated and the temperature of the object to be heated can be measured more accurately.

[0006] On the other hand, the disadvantage of the thermopile sensor of the prior art is that the "thermal shock" effect occurs due to the rapid increase in the air temperature inside the microwave oven. The thermal shock effect is caused by the package shell effect. Generally, the input of the thermopile sensor can be divided into two parts, one of which is the external input from the external radiation of the object to be measured, and the other is the thermal radiation from the package shell of the thermopile sensor. When the temperature of the lid is unbalanced with the cold end of the thermopile sensor, the thermal shock effect occurs due to the disturbance of the air temperature inside the microwave oven. The thermal shock effect will affect the accuracy of the measured temperature.

[0007] Therefore, how to design a temperature sensor device that can provide a narrow field of view, resist microwave interference, and accurately measure temperature is an important topic studied by the inventors. On the other hand, using a visible light source with the same field of view can facilitate the placement of the object to be heated, thereby providing another practical function. Summary of the invention

[0008] One of the purposes of the present invention is to provide a temperature sensing device. Compared with the prior art, the present invention adopts a metal sleeve plus a metal grid design on the packaging of the thermopile sensor component to block the entry of microwaves, thereby improving the accuracy of the thermopile sensor.

[0009] In some embodiments, in order to overcome the measurement error caused by the thermal shock effect of the packaging shell caused by the sudden rise in internal temperature during microwave heating, the thermopile sensor of the present invention adopts a dual thermopile sensor component design, in which one thermopile sensor component (for example, an active thermopile sensor element) measures the infrared thermal radiation of the object to be measured, and the other thermopile sensor component (for example, a dummy unit thermopile sensor component) is used to measure the thermal radiation of the packaging shell as compensation for thermal shock, so as to achieve the purpose of accurate temperature measurement.

[0010] In addition, in view of the narrow field of view required for microwave oven temperature measurement, the infrared lens used in the present invention can provide a narrow field of view of, for example, 5-15 degrees. A metal sleeve can be added outside the metal packaging shell to block heat radiation outside the field of view, and a metal mesh is provided on the window of the metal sleeve to isolate the entry of microwaves, so as to meet the demand for accurate temperature measurement during microwave heating.

[0011] In some embodiments, the infrared lens may be a spherical lens or a silicon Fresnel lens to provide a narrow field of view for the thermopile sensor.

[0012] In some embodiments, the field of view of the infrared lens is less than or equal to 15 degrees and greater than or equal to 5 degrees.

[0013] In some embodiments, the infrared lens may include an anti-reflective coating to increase the penetration of infrared thermal radiation.

[0014] In some embodiments, the signal processing dedicated chip also includes a low noise amplifier, a multiplexer, an analog-to-digital converter (ADC), a non-volatile memory, and a communication interface.

[0015] In some embodiments, the analog-to-digital converter is a high-resolution sigma-delta analog-to-digital converter.

[0016] In order to facilitate users to examine the food placed on the turntable, the present invention adds a visual design, and adds a visible light source with a similar narrow field of view next to the thermopile sensor. The light source can be a light emitting diode (LED) or a laser light source with a beam expander.

[0017] In summary, in order to solve the interference of microwaves on thermopile sensors during microwave heating, the present invention adds a metal sleeve with a metal grid to the outside of the packaging shell of the thermopile sensor. In addition, in order to overcome the problem of thermal shock effect caused by internal air temperature disturbance, the present invention provides a temperature sensing device with a dual thermopile sensor assembly. The active thermopile sensor element is used to sense the temperature data of the heated object (such as food) in the microwave oven. The dummy unit thermopile sensor assembly is used to sense the thermal radiation of the packaging shell in the metal packaging shell, and the thermal radiation of the packaging shell is caused by the air temperature disturbance inside the microwave oven, such as the rapid increase of the air temperature inside the microwave oven. The dedicated signal processing chip obtains the accurate temperature of the object by compensating for the thermal shock effect through temperature data and thermal radiation of the packaging shell.

[0018] Therefore, compared with the prior art, the present invention compensates for the thermal shock effect caused by the air temperature disturbance inside the microwave oven, achieving the purpose of accurate temperature measurement. At the same time, it adopts an optical design with a narrow field of view, which can accurately measure the surface temperature of an object without being affected by the background ambient temperature. The added visual design allows users to more easily understand the position of the food to be heated measured by the thermopile sensor.

[0019] In order to further understand the technology, means and effects adopted by the present invention to achieve the predetermined purpose, please refer to the following detailed description and drawings of the present invention. It is believed that the characteristics and features of the present invention can be understood in depth and in detail. However, the drawings are only provided for reference and explanation and are not intended to limit the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is an exploded view of the temperature sensing device of the present invention;

[0021] Figure 2 is an exploded view of the thermopile sensor assembly of the present invention;

[0022] Figure 3 is an exploded view of a first embodiment of a thermopile sensor of the present invention;

[0023] Figure 4 is an exploded view of a second embodiment of a thermopile sensor of the present invention;

[0024] Figure 5 It is a block diagram of a dedicated chip for signal processing of a thermopile sensor of the present invention;

[0025] Figure 6 is an exploded view of a first embodiment of a temperature sensing device including a visible light source according to the present invention;

[0026] Figure 7 is an exploded view of a second embodiment of a temperature sensing device including a visible light source according to the present invention;

[0027] Description of reference numerals:

[0028] 100, 100a, 100b: temperature sensing device;

[0029] 101: Thermopile sensor assembly;

[0030] 102: substrate;

[0031] 103: signal connector terminal;

[0032] 104, 105: visible light source;

[0033] 106: beam expander;

[0034] 110, 110a, 110b: thermopile sensor;

[0035] 111: Metal sleeve;

[0036] 112: window;

[0037] 113: Metal grid;

[0038] 201: Metal base;

[0039] 202a: thermopile sensor element (active thermopile sensor element);

[0040] 202b: thermopile sensor element (dummy unit thermopile sensor element);

[0041] 203: ambient temperature sensor;

[0042] 204: dedicated chip for signal processing;

[0043] 205: metal packaging shell;

[0044] 206: window;

[0045] 207: Infrared lens;

[0046] 208: conductor post;

[0047] 209: signal pin;

[0048] 301: a first multiplexer;

[0049] 302: Low noise amplifier;

[0050] 303: second multiplexer;

[0051] 305: buffer amplifier;

[0052] 306: analog-to-digital converter;

[0053] 307: filter;

[0054] 308: register;

[0055] 309: state machine;

[0056] 310: communication interface;

[0057] 311: non-volatile memory;

[0058] 312: interface signal;

[0059] DX: Irradiated area. DETAILED DESCRIPTION

[0060] The following describes the implementation of the present invention through specific embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific examples, and the details in the present invention specification can also be modified and changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0061] The technical content and detailed description of the present invention are described as follows with reference to the accompanying drawings.

[0062] Figure 1 1 is an exploded view of the temperature sensing device of the present invention. The temperature sensing device 100 comprises a thermopile sensor assembly 101 having a metal sleeve, a substrate 102 and a signal connector terminal 103. The metal sleeve of the thermopile sensor assembly 101 has a metal grid on it to block microwaves from entering the metal sleeve, and the metal sleeve is connected to the microwave oven ground wire through the signal connector terminal 103.

[0063] Figure 2 1 is an exploded view of the thermopile sensor assembly 101 of the present invention. The thermopile sensor assembly 101 is composed of a thermopile sensor 110 and a metal sleeve 111. The metal sleeve 111 has a window 112, and a metal grid 113 is provided on the window 112 to block the entry of microwaves and allow infrared radiation of the object to be measured to pass through. The metal grid 113 can also be placed inside the window 112.

[0064] Figure 31 is an exploded view of the first embodiment of the thermopile sensor 110a of the present invention. In the first embodiment, the thermopile sensor 110a adopts a metal package shell 205. The thermopile sensor 110a has a metal base 201. The metal base 201 is used to fix the components and has a plurality of wire posts 208 and a plurality of signal pins 209 for providing signal leads. The thermopile sensor element 202a, the ambient temperature sensor 203 and the signal processing dedicated chip 204 are fixed on the metal base 201. The ambient temperature sensor 203 can be composed of a thermistor. A metal package shell 205 is provided on the metal base 201. A window 206 is provided on the metal package shell 205. An infrared lens 207 can be fixed on the window 206. The infrared lens 207 can be a spherical lens or a silicon Fresnel lens. The infrared lens 207 can be an external type (outside the metal package shell 205) or a built-in type (inside the metal package shell 205).

[0065] Figure 4 2 is an exploded view of the second embodiment of the thermopile sensor 110b of the present invention. The thermopile sensor 110b also uses a metal package shell 205. The thermopile sensor 110b has a metal base 201. The metal base 201 is used to fix the components and has a plurality of wire posts 208 and a plurality of signal pins 209 for providing signal leads. The thermopile sensor element 202a, the thermopile sensor element 202b, the ambient temperature sensor 203 and the signal processing dedicated chip 204 are fixed on the metal base 201. The ambient temperature sensor 203 can be composed of a thermistor. A metal package shell 205 is provided on the metal base 201. A window 206 is provided on the metal package shell 205. An infrared lens 207 can be fixed on the window. The infrared lens 207 can be a spherical lens or a silicon Fresnel lens. The infrared lens 207 can be an external type (outside the metal package shell 205) or a built-in type (inside the metal package shell 205). In addition, the thermopile sensor element 202a is an active thermopile sensor element, which is used to sense the infrared thermal radiation of the external object to be measured. The thermopile sensor element 202b is a dummy unit thermopile sensor element, which is used to sense the thermal radiation of the metal package 205 as a compensation for thermal shock, so as to solve the error of the package effect caused by the rapid rise of the ambient temperature in the oven when the microwave oven is heated.

[0066] Thermopile sensor 110a (eg Figure 3 The temperature measured is calculated as follows.

[0067] T_mea=T_th+ΔT_tp+ΔT_cap

[0068] Wherein, T_mea is the temperature measured by the thermopile sensor 110 a , T_th is the temperature measured by the ambient temperature sensor 203 , ΔT_tp is the temperature difference measured by the thermopile sensor element 202 a , and ΔT_cap is the temperature difference of the metal packaging shell 205 .

[0069] In the thermopile sensor 110b (eg, Figure 4 When

[0070] T_mea=T_th+ΔT(=Tp_active–k*TP_dummy)

[0071] The output of the active thermopile sensor element 202a minus a constant k multiplied by the output of the dummy thermopile sensor element 202b is converted into a temperature difference ΔT, and then added with the temperature measured by the ambient temperature sensor 203 to obtain the temperature T_mea of ​​the object to be measured after correcting the package effect.

[0072] In some embodiments, the dummy unit thermopile sensor element 202b is fixed to the outer edge of the metal base 201, and the metal sleeve 111 (such as Figure 1 Under the limitation of the above (as shown in FIG. 1 ), the dummy unit thermopile sensor element 202b can only receive the infrared thermal radiation of the metal package 205. The infrared thermal radiation received by the active thermopile sensor element 202a includes the infrared thermal radiation of the external object to be measured and the infrared thermal radiation of the metal package 205.

[0073] Therefore, in order to solve the problem of thermal shock effect caused by the air temperature disturbance inside the microwave oven, the present invention provides a temperature sensing device 101 having a thermopile sensor assembly 101. The active thermopile sensor element 202a is used to sense the temperature data of the heated object (such as food) in the microwave oven. The dummy unit thermopile sensor element 202b is used to sense the thermal radiation of the package shell in the metal package shell 205, and the thermal radiation of the package shell is caused by the air temperature disturbance inside the microwave oven, such as the rapid increase of the air temperature inside the microwave oven. The dedicated integrated circuit chip 204 obtains the accurate temperature of the object by compensating the thermal shock effect through the temperature data and the thermal radiation of the package cap.

[0074] Figure 52 is a block diagram of a dedicated signal processing chip 204 of a thermopile sensor of the present invention. The dedicated signal processing chip 204 of the temperature sensing device of the present invention receives inputs of thermopile sensing elements 202a and 202b and inputs of an ambient temperature sensor 203. In some embodiments, the dedicated signal processing chip 204 includes a low noise amplifier 302, a first multiplexer 301, a second multiplexer 303, an analog-to-digital converter (ADC) 306, a non-volatile memory 311, and a communication interface 310. In addition, the analog-to-digital converter 306 may be a high-resolution sigma-delta analog-to-digital converter.

[0075] In some embodiments, thermopile signals from active thermopile sensing element 202a and dummy cell thermopile sensing element 202b pass through first multiplexer 301 to low noise amplifier 302 and then are selected by second multiplexer 303 before being fed to analog-to-digital converter 306, which is non-limiting.

[0076] In some embodiments, the signal processing dedicated chip 204 also receives input from the ambient temperature sensor 203. The ambient temperature signal is buffered by the buffer amplifier 305 and then selected by the second multiplexer 303 before being fed to the analog-to-digital converter 306, which is non-limiting.

[0077] In some embodiments, the digital signal converted by the analog-to-digital converter 306 is filtered by the filter 307 and then stored in the register 308 , which is non-limiting.

[0078] In some embodiments, the communication interface 310 is used to read or write the register 308 and control the operation of the signal processing dedicated chip 204, such as selecting sensor signals, starting the analog-to-digital converter 306, and reading / storing calibration parameters in the non-volatile memory 311, etc., but this is not limiting.

[0079] In some embodiments, the communication interface 310 may include I 2 C interface, however non-restrictive.

[0080] In some embodiments, the signal processing dedicated chip 204 may also include a state machine 309 (e.g., a microcontroller), which is triggered by the communication interface 310 to select a sensor channel, trigger the operation of the analog-to-digital converter 306, and store the digital signal converted by the analog-to-digital converter 306 in a register 308 or a non-volatile memory 311, which is non-limiting.

[0081] In some embodiments, the communication interface 310 may communicate with an external microcontroller (not shown) via an interface signal 312 , which is not limiting.

[0082] Please refer to Figure 3 or Figure 4 In some embodiments, the infrared lens 207 may be a spherical lens or a silicon Fresnel lens and may include an anti-reflection coating to increase the infrared transmission coefficient and increase the transmittance of infrared thermal radiation input to the ASIC chip 204, however, this is not limiting.

[0083] Figure 6 1 is a diagram of a first embodiment of a temperature sensing device 100a of the present invention including a visible light source 104. The visible light source 104 of the temperature sensing device 100a allows the user to place the object to be heated within the field of view of the thermopile sensor assembly 101. The thermopile sensor assembly 101 is designed with a narrow field of view, and its field of view is 5-15 degrees. The visible light source 104 can be, for example, an LED light source, and its field of view is the same as that of the thermopile sensor assembly 101. The area illuminated by the visible light source 104 is the sensing area of ​​the thermopile sensor assembly 101 after DX is offset. In practice, DX is less than or equal to 1 cm.

[0084] Figure 7 FIG. 1 is an exploded view of a second embodiment of a temperature sensing device 100 b of the present invention including a visible light source 105 . The visible light source 105 may be a visible light laser module having a laser diode. In some embodiments, the visible light source 105 may be equipped with a beam expander 106 to adjust the laser light source diffusion angle to be the same as the field of view of the thermopile sensor assembly 101 .

[0085] In summary, the temperature sensing device of the present invention can resist the interference of microwaves and can also measure the temperature of the object to be heated during the heating process. At the same time, in order to solve the problem of thermal shock effect caused by the air temperature disturbance inside the microwave oven, the present invention also provides a temperature sensing device with a dual thermopile sensor assembly. The active thermopile sensor element is used to sense the temperature data of the heated object (such as food) in the microwave oven. The dummy unit thermopile sensor assembly is used to sense the thermal radiation of the packaging shell in the metal packaging shell, and the thermal radiation of the packaging shell is caused by the air temperature disturbance inside the microwave oven, such as the rapid increase of the air temperature inside the microwave oven. The dedicated signal processing chip obtains the accurate temperature of the object by compensating the thermal shock effect through the temperature data and the thermal radiation of the packaging shell.

[0086] It is worth mentioning that in some embodiments, in order to locate the central temperature of an object, the thermopile sensor must be used in a narrow field of view (e.g., 5-15 degrees) to accurately measure the temperature of the object to be measured, rather than measuring the sum of the object to be measured and the background temperature. Therefore, the present invention also provides a visible light source to display the sensing area of ​​the thermopile sensor. The visible light source can be an LED or a visible light laser, and its irradiation angle is the same as the field of view of the thermopile sensor.

[0087] Therefore, compared with the prior art, the present invention compensates for the thermal shock effect caused by the air temperature disturbance inside the microwave oven, achieving the purpose of accurate temperature measurement. At the same time, it adopts an optical design with a narrow field of view, which can accurately measure the surface temperature of an object without being affected by the background ambient temperature. The added visual design makes it easier for users to understand the position of the dual thermopile sensor measuring the food to be heated.

[0088] The above description is only a detailed description and drawings of the preferred specific embodiments of the present invention, but the features of the present invention are not limited thereto, and the present invention is not limited thereto. The entire scope of the present invention shall be subject to the following patent application scope. All embodiments that conform to the spirit of the patent application scope of the present invention and similar variations thereof shall be included in the scope of the present invention. Any changes or modifications that can be easily thought of by anyone familiar with the art within the field of the present invention shall be covered by the following patent scope of this case.

Claims

1. A temperature sensing device, characterized in that: include: a substrate; a thermopile sensor assembly, disposed on the substrate, comprising a metal sleeve, a metal grid and a thermopile sensor, wherein the metal grid is disposed in a window of the metal sleeve, and the thermopile sensor is located in the metal sleeve; as well as a signal connector terminal, disposed on the substrate, Wherein, the thermopile sensor comprises: A metal base; A metal packaging shell, covering the metal base; One or more thermopile sensor components are disposed on the metal base and encapsulated by the metal encapsulation shell; An ambient temperature sensor, disposed on the metal base; an infrared lens disposed at a window of the metal package to provide infrared radiation to the thermopile sensor assembly; and A dedicated chip for signal processing is arranged on the metal base.

2. The temperature sensing device according to claim 1, characterized in that: The infrared lens is a spherical lens or a silicon Fresnel lens.

3. The temperature sensing device according to claim 1, characterized in that: The viewing angle of the infrared lens is greater than or equal to 5 degrees and less than or equal to 15 degrees.

4. The temperature sensing device according to claim 1, characterized in that: The infrared lens has an anti-reflection coating to increase the transmittance of the infrared radiation.

5. The temperature sensing device according to claim 1, characterized in that: The thermopile sensor includes two thermopile sensor components, one of which is an active thermopile sensor element for sensing the infrared thermal radiation of an external object to be measured, and the other of which is a dummy unit thermopile sensor component for sensing the infrared thermal radiation of the metal packaging shell.

6. The temperature sensing device according to claim 1, characterized in that: The signal processing dedicated chip also includes a low noise amplifier, a multiplexer, an analog-to-digital converter, a non-volatile memory and a communication interface.

7. The temperature sensing device according to claim 6, characterized in that: The analog-to-digital converter is a delta-sigma analog-to-digital converter.

8. A temperature sensing device, characterized in that: include: a substrate; a thermopile sensor assembly, disposed on the substrate, comprising a metal sleeve, a metal grid and a thermopile sensor, wherein the metal grid is disposed in a window of the metal sleeve, and the thermopile sensor is located in the metal sleeve; as well as a visible light source, disposed on the substrate; as well as a signal connector terminal, disposed on the substrate, Wherein, the thermopile sensor comprises: A metal base; A metal packaging shell, covering the metal base; One or more thermopile sensor components are disposed on the metal base and are metal packaged; An ambient temperature sensor, disposed on the metal base; an infrared lens disposed at a window of the metal package to provide infrared radiation to the thermopile sensor assembly; and A dedicated chip for signal processing is arranged on the metal base.

9. The temperature sensing device according to claim 8, characterized in that: The visible light source is a light emitting diode or a laser diode.

10. The temperature sensing device according to claim 8, characterized in that: The field of view angle of the visible light source is the same as the field of view angle of the thermopile sensor.

11. The temperature sensing device according to claim 9, characterized in that: The laser diode also includes a beam expander.

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