JP2005195435A - Noncontact type temperature detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive and small-sized noncontact type temperature detector hardly influenced by an installation surrounding environment by storing a thermopile infrared sensor in a metal can case without any special difference from a conventional manufacturing technology process. <P>SOLUTION: This detector has a constitution capable of stable and accurate temperature measurement against a sudden temperature change of the sensor ambient temperature, by adopting a double structure wherein the TO-18 type thermopile infrared sensor formed by arranging a thermopile element and a thermistor is packaged and stored in the metal can case having the maximum sectional area of 155.4 square millimeter or less. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a non-contact temperature detector that performs temperature measurement in a non-contact manner for the purpose of temperature control.

  A thermopile is widely known as an infrared sensor that performs temperature detection without contact. A temperature detection sensor module using a thermopile generally includes components 18a and 18b constituting a circuit unit for amplifying a signal output from the thermopile infrared sensor 17 or performing output processing as shown in FIG. It is mounted on the external connection wiring board 19 and the signal processed output is taken out by the connector terminal 20.

  The infrared sensor module configured in this way is an optimum circuit configuration that assumes various installation environment conditions when mounted as a non-contact type temperature detector, for example, for various temperature measurement such as a cooker and an air conditioner. used. The thermopile infrared sensor 17 can obtain a signal output by the temperature difference generated between the hot junction and the cold junction of the thermopile element serving as the light receiving element portion, that is, the difference between the target object temperature and the infrared sensor self ambient temperature. In order to stabilize the detection accuracy of the object temperature, it is desirable that the self-temperature of the infrared sensor itself is as stable as possible. However, in actual use, in the environment surrounding the temperature detector, since a rapid temperature change of the ambient temperature is sufficiently assumed, the heat sink 21 may be used for the purpose of providing a sensor module that is not affected by the temperature change. In order to increase the heat capacity of the infrared sensor itself and intentionally delay the temperature follow-up, the heat sink 21 is used, for example, in contact with the case surface of the thermopile infrared sensor 17 as shown in FIG.

In the non-contact temperature detector, the thermopile infrared sensor 17 that receives infrared rays and generates a signal output is exposed on the surface, and protects the decorative relationship and dirt such as dust and water vapor components from the surrounding environment. For this purpose, a cover material (for example, polyethylene material) that transmits infrared light is provided and used on the front surface of the infrared sensor.
Japanese Patent Application No. 2003-287064

  The problem to be solved is that in the infrared sensor module in which the thermopile infrared sensor 17 shown in FIG. 7 is provided with a heat sink 21 so as not to be affected by a sudden temperature change in the surrounding environment, the heat sink 21 is separately provided. In addition to having to be prepared and equipped, it is necessary to provide a minimum volume space for the heat sink at the periphery of the thermopile infrared sensor 17, which limits the reduction in the volume size of the entire sensor module. .

  In the infrared sensor module, since the signal output processing circuit is mounted on the external wiring board, it is exposed to the actual installation environment. Even when a cover material is provided as an antifouling mechanism, the board surface is completely Therefore, there is a problem that the sensor module is inferior in environmental resistance performance due to poor moisture and dust resistance and external noise.

  In order to solve the above-described problems, the present invention provides a thermopile infrared in which a thermopile element for detecting infrared rays from a target object and a thermistor for detecting the ambient temperature of the thermopile element are casing together by a TO-18 type metal CAN case and a header. The sensor is hermetically sealed with a header having lead terminals for electrical connection with the thermopile infrared sensor and a metal CAN case having an infrared transmitting material having a maximum cross-sectional area of 155.54 square millimeters or less. An air insulation layer is formed between the thermopile infrared sensor and the outside air, so that it is not affected by sudden changes in the ambient temperature of the installation (a structure in which the thermopile element, which is the infrared sensor, is double hermetically sealed) It is a non-contact temperature detector There.

  In addition, the metal CAN case that houses the thermopile infrared sensor is subjected to an infrared reflection plating process (for example, chromium) in order to reduce infrared absorption for the purpose of reducing the temperature variation of the case itself due to a sudden temperature change of the installation ambient temperature. Plating) or the like.

  Further, the thickness of the metal CAN case itself may be configured to be, for example, a maximum wall thickness of 2.5 millimeters or less to increase the heat capacity of the case itself, and the metal CAN case itself may have a function as a heat sink.

  Conventionally, the processing circuit unit for sensor signal output has been provided on the external substrate. However, by using the structure shown in FIG. 1, the components of the signal output processing circuit are provided in the space of the casing housing the thermopile infrared sensor. Are mounted on a wiring board having a maximum plane area of 100.78 square millimeters or less, and are electrically connected to the TO-18 type thermopile infrared sensor to have a maximum sectional area of 155.54 square. It is possible to construct a single and small infrared sensor module by packaging in a casing of millimeter or less. Here, by externally sealing the signal output processing circuit section with a metal CAN case, it is possible to completely remove external factors such as the influence on the sensor signal output by external electromagnetic waves.

  Furthermore, depending on the application specifications of the non-contact type temperature sensor, it may be configured only with a metal CAN case having an outer infrared transmitting material without providing a double hermetic seal structure, and a wide distance between the thermopile element and the external air may be taken. Thus, it is possible to reduce the degree of influence on the temperature change of the surrounding environment.

  According to the non-contact type temperature detector of the present invention, a conventionally manufactured TO-18 type thermopile infrared sensor is packaged in a metal CAN case having a maximum cross-sectional area of 155.54 square millimeters or less, so The thermopile infrared is provided without an additional heat sink for stabilizing the cold junction part of the thermopile element by providing an air heat insulation layer that interrupts and avoids sudden temperature changes, that is, to stabilize the self ambient temperature of the infrared sensor. By providing the sensor signal output processing circuit part in the space part of the casing housing the sensor, the infrared sensor module can be configured, and the capacity size of the sensor module can be reduced. The thermopile infrared sensor has a structure in which a thermopile element that is an infrared light receiving portion and a thermistor that is a temperature sensing portion are in the same casing. Therefore, since the thermopile element and the thermistor are double packaged, the influence of the surrounding environment (abrupt Temperature change, contamination, moisture and dust resistance, external noise, etc.). Accordingly, it is possible to provide an excellent non-contact type temperature detector that can stabilize the temperature of the infrared sensor itself, accurately detect the temperature of the target object, and is not affected by external electromagnetic waves.

  Further, here, in the metal CAN case having the maximum cross-sectional area of 155.54 square millimeters or less, an infrared reflection plating process for reducing infrared absorption is performed, or the case itself has a maximum thickness of 2 to increase the heat capacity of the case. If a case having a structure of .5 mm or less is used, a heat insulating effect from the external atmosphere can be further expected.

  In addition, the package size mentioned in this example is an upper surface side sectional area of 113.49 to 117.82 square millimeters, a lower surface side sectional area of 150.81 to 155.54 square millimeters, and a side surface sectional area of 75.56 to 81. Since the flat type package type of .67 square millimeters is generally used and produced, it can be provided as a low-cost and small-sized infrared sensor module by conventional manufacturing technology, and an external connection board for fixing the sensor module. As a result, the temperature detector itself can be reduced in cost and reduced in size and weight.

  The structure shown in FIG. 1 and the circuit configuration shown in FIG. 3 are realized by a conventional manufacturing technique and assembly process as a non-contact temperature detector that is not affected by a sudden temperature change in the surrounding environment of the installation.

  First, a non-contact temperature detector according to the present invention will be described in detail with reference to FIG. In this embodiment, the thermopile infrared sensor and the sensor signal output processing circuit unit are cited as a small non-contact type temperature detector in which the same package is accommodated. In FIG. 1, a metal CAN case 8 having a maximum cross-sectional area of 155.54 square millimeters or less having a filter material that allows infrared rays to enter and transmit, a TO-18 type thermopile infrared sensor 10 in which a thermopile element 1 and a thermistor 2 are arranged, an operational amplifier IC 11, 12; board 6 on which circuit components 13a, 13b such as resistors and capacitors are mounted; lead terminals for taking out output signals from the thermopile infrared sensor 10 and supporting the board 6 for electrical connection and mechanical fixing The header 7 provided with 9 is a hermetic seal in order to prevent environmental changes and electromagnetic interference from outside.

  Here, the substrate 6 is a thin plate having a maximum plane area of 100.78 square millimeters or less on which internal wiring is formed (not shown in FIG. 1 because wiring is complicated). The thermopile infrared sensor 10 is arranged by wire-connecting a thermopile element 1 that receives infrared rays and a thermistor 2 that is a temperature reference element for infrared sensor self-temperature sensing, and the metal CAN case 4 having an infrared transmission window and the above-described thermopile infrared sensor 10. This is a general TO-18 type package type hermetically sealed by a header 3 having a lead terminal 5 in which a thermopile element and a thermistor are electrically connected. The metal CAN case 4 of the TO-18 type thermopile infrared sensor 10 and the outer metal CAN case 8 forming a flat type are used as an infrared filter with a silicon material or a polyethylene material.

  FIG. 2 is an external shape diagram of the non-contact temperature detector according to the present embodiment, and the package sizes when viewed from the upper surface A, the lower surface B, and the side surface C are respectively the upper surface A side sectional areas 113.49 to 117. .82 square millimeters, lower surface B side sectional area 150.81 to 155.54 square millimeters, and side C side sectional area 75.56 to 81.67 square millimeters.

  FIG. 3 is an example of an internal wiring circuit diagram of the non-contact type temperature detector according to the present embodiment, and shows a method of taking out the thermopile signal output and the thermistor signal output independently as amplified outputs. FIG. 4 shows a non-contact type temperature detector in which the target object is mounted on a device that measures the temperature in a non-contact manner using the non-contact type temperature detector according to this embodiment, and the installation ambient temperature is experimentally changed. The result of having plotted the measured temperature obtained from is shown. In addition, as a simultaneous evaluation, the measured temperature in the case of using the conventional heat sink-equipped non-contact temperature detector shown in FIG. 7 is similarly shown as a dotted line plot in FIG. Here, the experimental condition is that the target object temperature is fixed at 50 ° C., the ambient temperature of the installation is increased by a temperature gradient of + 2 ° C./min from the time when it is stabilized at 25 ° C., and the temperature is kept from the time when it reaches 40 ° C. When the ambient temperature changes rapidly, the measured temperature of the conventional type equipped with the heat sink shows a minimum measured value of 49.6 ° C. and a maximum measured value of 50.5 ° C. It can be seen that the detector has a minimum measured value of 49.8 ° C. and a maximum measured value of 50.3 ° C., and a highly accurate measured temperature equivalent to or higher than that of the conventional type can be obtained. From these experimental results, since the thermopile infrared sensor and the signal output amplifier circuit part are packaged in a single case, the non-contact temperature detector according to the present embodiment is actually installed such as a sudden temperature change and air convection. It was confirmed that there was an excellent effect on the influence of the surrounding environment.

  The operation of the non-contact temperature detector of this embodiment as a temperature measurement application is to receive infrared rays from a target object and generate an output according to a temperature difference from the infrared sensor self-temperature and the thermopile device 1. The output of the infrared sensor self-temperature sensing thermistor 2 disposed in the vicinity of the cold junction is detected through an amplifier circuit unit composed of operational amplifiers IC11 and 12, resistors R1 to R5 and capacitors C1 and C2. The detection signal output can be directly taken out from the lead terminal 9 which is electrically connected only by providing a simple external connection board equipped with a connector terminal for taking out the signal output of the minimum plane area size. Become.

  5 and 6 show another example of the internal wiring circuit diagram of the non-contact temperature detector according to the present embodiment. 5 shows a circuit configuration in which the thermistor signal output is taken out as a divided output from the operation reference potential determined by the Zener diode 14 or a three-terminal regulator. In FIG. 6, the operation reference potential of the thermopile signal output is shown as the second operational amplifier. 12 is a circuit structure in which a thermistor signal output amplified by 12 is used, gain adjustment is performed by a variable resistor 16 connected to one side input terminal of the first operational amplifier 11, and a thermopile signal output that does not depend on a change in ambient temperature of the installation is obtained. Here, the input resistor 15 related to the first operational amplifier 11 for amplifying the thermopile signal output shown in FIGS. 3 and 5 may be used as the variable resistor 16 whose gain can be adjusted as shown in FIG. As a signal output processing circuit unit that is optimal for each application, for example, a cooking appliance, an air conditioner, or the like equipped with a non-contact temperature detector in this way, operational amplifiers IC11 and 12, resistors R1 to R5, and variable resistor 16 It is also possible to easily select the wiring of the capacitors C1 and C2 on the internal substrate 6.

  In the non-contact type temperature detectors according to some embodiments configured as described above, the analog signal output processing circuit unit from the sensor is housed in the same package as the thermopile infrared sensor. A post-processing circuit for performing digital processing or arithmetic processing on the output can be constructed as a temperature measuring device that is reduced in size and weight by providing an external connection board having a minimum plane area size that can be mounted. These can be configured without being different from conventional manufacturing techniques and assembly processes.

It is a disassembled external view which shows the non-contact-type temperature detector of one Example of this invention. It is an external view of the non-contact type temperature detector of one Example of this invention. It is a circuit diagram of the non-contact type temperature detector of one Example of this invention. It is a verification experiment result of the temperature measurement of the non-contact-type temperature detector of one Example of this invention. It is a circuit diagram of the non-contact-type temperature detector of the other Example of this invention. It is a circuit diagram of the non-contact-type temperature detector of the other Example of this invention. It is an external view which shows the non-contact-type temperature detector using the conventional thermopile infrared sensor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Thermopile element 2 Thermistor 3 TO-18 type header 4 TO-18 type metal CAN case 5, 9 Lead terminal for external extraction 6 Internal wiring board 7 Header 8 Metal CAN case 10 TO-18 type package thermopile infrared sensor 11 First operational amplifier DESCRIPTION OF SYMBOLS 12 2nd operational amplifier 13a, 13b, 18a, 18b Electronic component for circuit composition 14 Zener diode 15 Input resistance which concerns on 1st operational amplifier 16 Variable resistance 17 Thermopile infrared sensor 19 External connection board 20 Connector terminal 21 Heat sink R1-R5 Resistance C1, C2 Capacitors A Direction indication on the upper surface side B Direction indication on the lower surface side C Direction indication on the side surface side

Claims (5)

  Infrared sensor module used for non-contact temperature measurement, etc. A header equipped with a thermopile element that detects infrared radiation of a target object as a sensor element and a temperature reference element that detects the ambient temperature near the cold junction of the thermopile element is an infrared sensor module. A thermopile infrared sensor disposed in the same casing by a metal CAN case having a transmission window is combined with a header having lead terminals that are electrically connected to the thermopile infrared sensor, and a metal CAN case having an infrared transmission material. A non-contact type temperature detector characterized by having a structure in which an air insulation layer is provided between the internal thermopile infrared sensor and the external atmosphere to stabilize the ambient temperature of the thermopile infrared sensor by accommodating and making a double structure.   The non-contact type temperature detector according to claim 1, wherein the metal CAN case accommodating the thermopile infrared sensor has a maximum cross-sectional area of 155.54 square millimeters or less.   The metal CAN case of the thermopile infrared sensor and the outer metal CAN case that accommodates the thermopile infrared sensor are both provided, or only the outer metal CAN case is provided and hermetically sealed. The non-contact type temperature detector according to claim 1 or 2.   The non-contact type temperature detector according to any one of claims 1 to 3, wherein the thermopile infrared sensor is housed in a casing of a TO-18 type package.   The non-contact temperature detector according to any one of claims 1 to 4, wherein the temperature reference element is a thermistor.

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