JP2008298627A - Infrared sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an infrared sensor capable of stably measuring the temperature of an object to be heated, by detecting abnormal output of the infrared sensor due to stains of the window material of the infrared sensor. <P>SOLUTION: The infrared sensor 100 is provided with a housing 2, having an infrared optical path to which an infrared-transmitting window material 6 is attached, infrared-light receiving elements 10 in a prescribed number, arranged in the housing 2 in such a manner that a light-receiving surface faces the infrared-transmitting window material 6 and having a received infrared wavelength region which is different from each other, and an infrared light source 12, disposed in the housing 2 in such a manner that an infrared irradiating surface faces the infrared-transmitting window material. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an infrared sensor that measures the temperature of a substance in a non-contact manner using infrared rays, and a heating device including the sensor.

  As an application example of this sensor, an infrared sensor that is attached to a heating cooker such as an induction heating cooker or a gas stove used especially for cooking, and detects the temperature of a heated object such as a pan in a non-contact manner. There is.

  Conventionally, for the purpose of preventing an unexpected accident such as a fire, a temperature sensor is attached to a heating device such as a stove to monitor the temperature of an object to be heated such as a pan.

  Patent Document 1 describes that the temperature of an object to be heated is measured by attaching an infrared detection element below the burner of the stove and detecting the infrared ray emitted from the object to be heated by the infrared detection element in a non-contact manner. Has been. In the above stove, when using the stove, in order to prevent the light receiving part of the infrared detecting element from being contaminated due to oil spilling, hot water spilling, falling dust, etc. during cooking, the detection sensitivity is reduced or changed. A window material is attached above the detection element. It also describes that an infrared detection element is attached obliquely below the burner so that the window material is not affected by oil spillage or the like as much as possible. However, there is no description regarding a method for cleaning a window material once soiled. Therefore, when the window material becomes dirty, the detected temperature becomes inaccurate.

  As a method for removing dirt from an infrared detection element, a method of attaching an infrared condensing lens having a photocatalyst to an opening of an infrared sensor is disclosed (Patent Document 2). In this method, light is applied to the photocatalyst from the light emitter, and the dirt adhering to the lens is decomposed and removed by a photolysis reaction. However, there is no specific description of the photocatalyst and the type of light irradiated on the photocatalyst.

  Patent Document 3 discloses a photocatalytic titanium oxide capable of transmitting infrared rays to the surface of the imaging lens base material in order to prevent reflection and refraction of infrared rays due to water droplets condensed on the surface of the imaging lens of the pyroelectric infrared detection device. The formation of a surface layer containing particles is disclosed. By irradiating the surface layer with ultraviolet rays, the hydrophilicity of the lens surface is increased, thereby making water droplets into a uniform adsorbed water layer. However, there is no description of decomposing lens dirt with a photocatalyst. Therefore, this document has no direct technical relationship with the present invention.

  Patent Document 4 discloses an infrared transmissive window material capable of automatically decomposing and removing attached dirt, an infrared sensor unit using the same, and a heating apparatus incorporating the infrared unit. This infrared sensor unit is equipped with an infrared transmissive window material and an ultraviolet light emitting diode in the housing, and the window material can be automatically decomposed by irradiating the window material with ultraviolet light from the ultraviolet light emitting diode. Are listed.

  However, the infrared sensor unit has a drawback that it takes a certain time to decompose the dirt. That is, it is difficult to measure the exact temperature until the dirt generated during cooking, such as boiling, is decomposed. In particular, when the solid food material covers the window material, the temperature cannot be measured, which is a fatal situation. As a countermeasure against this, Patent Document 5 proposes a method for preventing contamination by attaching dirt to the infrared detection means and preventing temperature measurement from being performed. There is a problem.

Furthermore, basically, from the viewpoint of safety, there is a need for a means for informing the cook of the dirt on the window material by voice or the like and automatically turning off the flame.
JP 2002-340339 A (Claims) Japanese Patent No. 3202562 (Claims) JP-A-9-229767 (Claims) JP 2006-266827 A (Claims) JP 2006-214653 A (Claims)

  The present invention has been made in view of the above circumstances, and an object of the present invention is to detect an abnormal output of the infrared sensor due to dirt on the window material in advance and to stably measure the temperature of the object to be heated, and the infrared sensor It is an object of the present invention to provide a heating device having a function of automatically extinguishing a flame by letting a cook or the like know that the soil has been soiled.

  The present invention is described below.

  [1] A housing having an infrared light path with an infrared transmission window member attached thereto, a predetermined number of infrared light receiving elements having different light reception infrared wavelength regions provided in the housing with a light receiving surface facing the infrared transmission window member, and an infrared ray An infrared sensor having an infrared light source provided in a housing with an irradiation surface facing the infrared transmission window member.

  [2] The infrared sensor according to [1], wherein a heat insulating sleeve is provided around the infrared light source.

  [3] The infrared sensor according to [1], wherein the infrared light source irradiates an upper portion of the infrared light receiving element of the infrared transmitting window material.

  [4] A housing having an infrared light path, an infrared transmission window member attached to the infrared light path at a predetermined angle, and a predetermined number of each other provided in the housing with the light receiving surface facing the infrared transmission window member An infrared sensor comprising: an infrared light receiving element having a different light receiving infrared wavelength region; an infrared light source attached to a housing opposite to the infrared light receiving element with respect to the infrared transmitting window material while directing an infrared irradiation surface to the infrared transmitting window material.

  [5] Any one of [1] to [4], wherein the heating means for heating the object to be heated, the means for controlling the heating amount of the heating means, and the intensity of infrared rays emitted from the object to be heated are detected. The infrared sensor described above, an on / off control of the infrared light source, and an arithmetic control means and a display means for detecting the presence or absence of dirt on the infrared transmitting window material from the output of the infrared light receiving element at the on time and at the off time, And a heating device that controls the amount of heating based on the intensity of infrared rays detected by the infrared sensor and controls the display means.

  In the infrared sensor of the present invention, since infrared rays are irradiated on the infrared transmission window material and the dirt of the infrared transmission window material is constantly observed, it is possible to reliably and immediately detect that the dirt has adhered to the window material. As a result, the element output of this infrared sensor becomes highly reliable over a long period of time.

  Furthermore, abnormalities in the output of the infrared sensor due to dirt on the window material can be detected, so the heating device incorporating this infrared sensor immediately informs the cook that the dirt has been made and automatically extinguishes the flame. Since the function can be provided, safety is improved.

  Hereinafter, the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a side sectional view showing an example of the infrared sensor of the present invention. In FIG. 1, 100 is an infrared sensor, and 2 is a cylindrical housing having a hollow inside. The bottom of the housing 2 is closed by a bottom wall 4. The upper part of the housing 2 is closed by an infrared transmitting window material 6. By the bottom wall 4 and the infrared transmitting window material 6, the hollow portion 8 of the housing 2 constitutes an infrared optical path isolated from the outside.

  A sensor mounting substrate 9 is erected on the bottom wall 4.

  A predetermined number (two in this figure) of infrared detecting elements 10 are mounted on the sensor mounting substrate 9 with the infrared light receiving surface thereof facing the infrared transmitting window material 6, and the optical axis of the infrared detecting element 10 is , Parallel to the optical axis X of the infrared light path. Any one of optical filters (not shown) that selectively transmit infrared rays in the range of 1.5 to 1.8, 2 to 2.4, 3.1 to 4.2, and 8 to 17 μm is provided in the infrared light receiving element 10. Is installed. The number of infrared light receiving elements is preferably 2 or more.

  An infrared light source 12 is mounted on the sensor mounting substrate 9, and an infrared optical axis 14 irradiated by the infrared light source 12 is inclined at a predetermined angle θ with respect to an optical axis X of an infrared optical path formed by the hollow portion 8. ing. θ is preferably 70 ° or less, more preferably 50 ° or less, and particularly preferably 30 to 5 °. As a result, the optical axis 14 of the infrared light source 12 irradiates the upper portion 16 of the infrared light receiving element 10 of the infrared transmitting window material 6.

  The infrared light source 12 is composed of a hot wire heater, a planar heater on which Pt, Ru or the like is printed, or a coil wire material such as nichrome, and preferably has no infrared wavelength dependency. The energization pattern to the infrared light source 12 is pulse energization, specifically, 1 to 10 Hz is sufficient.

  Reference numeral 18 denotes a cylindrical heat insulating sleeve formed so as to cover the periphery of the infrared light source 12, and the upper part thereof is open. The heat insulating sleeve 18 prevents heat from the infrared light source 12 from being transmitted to the infrared light receiving element 10 to heat the infrared light receiving element 10. Reference numeral 20 denotes a lead wire of the infrared light receiving element 10 through which a detection signal corresponding to the amount of infrared light incident on the infrared light receiving element 10 is taken out.

  A lead wire 22 supplies power to the infrared light source 12, and power is supplied to the infrared light source 12 via the lead wire 22 to emit infrared light.

  The infrared transmitting window material 6 is a flat plate formed of a material that can transmit infrared rays. Examples of the material include silicon, germanium, sapphire, quartz, zinc selenide, zinc sulfide, sodium chloride, potassium chloride, potassium bromide, calcium fluoride, magnesium oxide, and the like. Selected. There is no restriction | limiting in particular also in the dimension of the infrared transmission window material 6, According to a use, it selects suitably.

  Next, the operation of the infrared sensor 100 will be described.

  Infrared rays radiated from a heated object (not shown) whose temperature is to be measured enter the hollow portion 8 through the infrared transmitting window material 6 of the infrared sensor 100, and then each infrared light receiving element. 10 detects the amount of infrared rays corresponding to the temperature of the object to be heated.

  The surface 24 of the infrared transmitting window material 6 is contaminated by the dirt 26 as time passes.

  On the other hand, infrared rays are emitted toward the surface 24 from the infrared light source 12 surrounded by the heat insulating sleeve 18. The irradiated infrared rays are reflected by the dirt 26 attached to the window material surface 24. The reflected infrared light is detected by the infrared light receiving element 10 and a detection signal corresponding to the amount of infrared light is transmitted to the outside through the lead wire 20. By observing this detection signal, the dirty state of the window can be determined. When the window material surface 24 is free of dirt 26, the light from the infrared light source is emitted to the outside. Accordingly, the output when the light source is ON is almost unchanged when there is no dirt, but when it is dirty, an output larger than usual is displayed.

  The temperature of the infrared light source 12 is preferably 50 to 1000 ° C.

  The infrared light source 12 is pulse energization control. However, any power such as direct current, alternating current, triangular wave, and pulse wave can be supplied as the power. In order to prevent overheating of the infrared light source 12, a pulse wave is preferable. Moreover, in order to distinguish and measure the temperature measurement of the heated object to be described later and the measurement of the amount of infrared rays based on dirt, it is preferable to use a pulse wave.

  FIG. 2 is a side sectional view showing another example of the infrared sensor of the present invention. In this example, the infrared light source 12 is provided with its optical axis aligned with the optical axis of the hollow portion 8. Furthermore, although the upper side of the heat insulating sleeve 18 is inclined and cut out, the other components are the same as those in FIG.

  In this example, the upper side of the heat insulating sleeve 18 is formed such that the wall a of the heat insulating sleeve 18 close to the infrared light receiving element 10 is lower than the wall b of the heat insulating sleeve 18 far from the infrared light receiving element 10. For this reason, the infrared rays emitted from the infrared light source 12 easily reach the upper portion 16 of the infrared light receiving element 10. Other reference numerals are the same as those in FIG.

  FIG. 3 is a side sectional view showing still another example of the infrared sensor of the present invention. In this example, the infrared transmissive window member 6 is mounted in the housing 2 at an included angle α of 90 ° C. or less with respect to the optical axis X of the infrared light path. α is preferably 80 ° to 10 °, more preferably 60 ° to 30 °. Further, the infrared light source 12 is attached to the wall 2 a of the housing 2 opposite to the infrared light receiving element 10 with respect to the infrared transmitting window material 6. Other reference numerals are the same as those in FIG. In the case of FIG. 3, when the infrared transmission window material 6 is not soiled, the infrared light emitted from the infrared light source passes through the infrared transmission window material 6 and enters the hollow portion 8, and the infrared light irregularly reflected by the inner wall enters the infrared light receiving element. Therefore, the output increases. When there is dirt, the infrared light is reflected by the dirt and does not enter the hollow portion 8, and therefore does not enter the infrared light receiving element. As a result, the output of the infrared light receiving element remains unchanged.

In this case, this example is an example in which an infrared light source is disposed horizontally with respect to the housing and an infrared transmission window material or lens is inclined in consideration of assemblability and outfitting. In this case, since the infrared light receiving element receives infrared energy from the infrared light source from the reflected light of the inner wall of the housing, it is desirable that the surface roughness of the inner wall is as good as possible. Note that this is not the case when there is no limit to the assemblability and the outfitting. For example, an infrared light source is disposed on the upper part so as to face the infrared light receiving element, and a mechanism that can be moved by an arm or the like is provided. You may make it move to the target position.
(Heating device)
FIG. 4 shows a stove 120 which is an example of the superheater of the present invention.

  In FIG. 4, 42 is a top plate, and a heating port 44 is formed. Around the heating port 44, a virtue 46 is disposed. A burner 48 is provided below the heating port 44 and includes an annular casing portion 50, a mixing tube 52 connected to the annular casing portion 50, and a gas nozzle 54 connected to the mixing tube 52. The gas supplied from the gas pipe 56 is discharged as a flame 59 from a flame port 58 formed in the annular casing portion 50 after air is mixed in the mixing pipe 52 through the nozzle 54. These constitute an example of the heating means.

  The heated object 60 is heated by the flame 59, and infrared rays corresponding to the temperature of the heated object 60 are emitted from the heated object 60. The emitted infrared rays reach the infrared sensor 100 through an infrared transmission hole 64 formed in the center of a juice receiving tray 62 disposed below the annular casing portion 50.

  This sensor 100 has the structure described in FIGS. Hereinafter, the infrared sensor shown in FIG. 1 will be described as an example. Infrared rays pass through the infrared transmitting window member 6 of the infrared sensor 100 shown in FIG. 1 and enter the hollow portion 8 constituting the infrared optical path, and then the infrared detecting element 10 detects the amount of infrared rays corresponding to the temperature of the object to be heated. . The infrared sensor 100 includes a plurality of infrared detection elements 10 having different detection wavelengths, and simultaneously detects infrared rays having different wavelengths, thereby reducing measurement errors. This method (multicolor method) uses at least two infrared detection elements in different wavelength regions, cancels the emissivity by calculating their output ratio, and the emissivity is increased. This is a method for detecting an accurate temperature even if they are different.

  The output of the infrared detection element 10 is sent to the arithmetic control means 65 for signal processing. For example, when the output of the infrared detecting element 10 indicates an overheated state of the object 60 to be heated or that the object 60 to be heated does not exist, a signal is sent to the adjusting valve 66 which is a heating amount control means, and the adjusting valve 66 Is closed, and the supply of the mixed gas supplied to the stove 120 is stopped. That is, they constitute an example of a heating amount control means of the heating means.

  In FIG. 1, when the infrared transmission window material 6 is not contaminated by the dirt 26, the infrared rays emitted from the infrared light source 12 are transmitted through the infrared transmission window material 6 and emitted to the outside of the infrared sensor 100. Infrared light emitted from the infrared light source 12 is hardly detected.

  The surface 24 of the infrared transmitting window 6 may be contaminated with the contents in the heated object 60 overflowing during cooking.

  In this case, the infrared rays irradiated from the infrared light source 12 are reflected by the dirt 26. The infrared light enters the infrared light receiving element 10 through the infrared transmitting window material 6. When the infrared light receiving element 10 sends a detection signal corresponding to the amount of incident infrared rays to the calculation control means 65 and the calculation control means 65 determines that there is dirt, for example, a signal is sent to the adjustment valve 66 and the adjustment valve 66 is closed. It is done. Further, a display means 68 such as an alarm is activated to notify the user that the infrared transmission window material 6 is dirty. When the user cleans the window material, the infrared sensor 100 returns to the initial state. Further, the arithmetic control means 65 has a function of performing on / off control of the infrared light source, detecting the output of the infrared light receiving element at the on time and at the off time, and comparing these outputs. It is to detect.

  Infrared light emitted from the infrared light source is a pulse signal and is detected by the light receiving element superimposed on the infrared light that is constantly emitted from the object to be heated. The degree of dirt is detected by reading.

  In the above description, the stove has been described as an example. However, the present invention is not limited to this, and the infrared sensor unit can be incorporated in various heating devices in the same manner. Furthermore, in the above example, the infrared sensor shown in FIG. 1 is used, but the present invention is not limited to this, and the infrared sensor shown in FIGS.

  Moreover, you may give the infrared ray transmission window material the photocatalyst function shown by Unexamined-Japanese-Patent No. 2005-274559.

  Next, the present invention will be specifically described by way of examples, but the present invention is not limited thereto.

Example 1
The infrared sensor shown in FIG. 1 was manufactured. A silicon infrared transmitting window material having a diameter of 4 cm and a thickness of 2 mm was attached to an aluminum housing having a diameter of 5 cm and a height of 8 cm. Two infrared light receiving elements were attached to the sensor mounting substrate so that the light receiving surface was positioned 6 cm below the infrared transmitting window material. As the infrared light receiving element, a thermopile was used, and filters having infrared transmission regions of 3.7 to 4.0 μm and 9.2 to 9.7 μm were attached.

  Similarly to the light receiving element, an infrared light source (trade name: infrared pulse light source manufactured by CAL-SENSOR) was attached. At that time, the optical axis of the infrared light source was tilted by 20 ° with respect to the infrared light path. As a result, the optical axis of the infrared light source intersected with the infrared transmission window material directly above the infrared light receiving element. Furthermore, a stainless steel cylindrical heat insulating sleeve was attached around the infrared light source.

  The lead wires of the infrared light source and the infrared light receiving element penetrated the bottom wall and were taken out of the infrared sensor.

  Using the above sensor, the change in display temperature when tap water adhered to the window material as a soiling substance was examined. A continuous pulse having a pulse height of 0.9 V, a pulse width of 0.5 ms, and a pulse interval of 0.5 ms was supplied to an infrared light source. In synchronization with this pulse, a signal was extracted from the light receiving element.

  The result is shown in FIG. The temperature of the object to be measured (heat source) was constant at 180 ° C. Assuming that the standard of measurement accuracy is the display temperature ± 15 ° C., the infrared rays emitted from the object to be heated are cut off only when the dirt material occupies 40% of the window material, and the display temperature deviates from the tolerance range.

  Next, a heating device shown in FIG. 4 was manufactured by incorporating the infrared sensor. This heating device accurately displayed the temperature of the object to be heated, and when the infrared transmission window material of the sensor became dirty, an alarm sounded and warned of the contamination.

Example 2
The infrared sensor shown in FIG. 3 was manufactured in the same manner as in Example 1 except that the mounting position of the infrared light source was different.

  Similarly to Example 1, the output change rate of the infrared light receiving element when the amount of the soiling substance (water) was changed was measured. The change rate is expressed as a ratio of the output decrease when the infrared light source is energized in a state where there is no dirt to 1 and the output decrease amount when the dirt is attached to the state where there is no dirt. The result is shown in FIG. It was found that the output of the infrared light receiving element obtained when the infrared light source is turned on decreases as the amount of soiling substances increases. In order to satisfy the accuracy standard ± 15 ° C., for example, by setting the threshold value to 0.5, it was possible to reliably detect the degree of contamination.

It is side surface sectional drawing which shows an example of the infrared sensor of this invention. It is side surface sectional drawing which shows another example of the infrared sensor of this invention. It is side surface sectional drawing which shows another example of the infrared sensor of this invention. It is the schematic which shows an example of a structure of the heating apparatus of this invention. It is a graph which shows the relationship between the occupation rate of the stain | pollution | contamination adhering to the infrared rays transparent window material of the infrared sensor of this invention, and display temperature. It is a graph which shows the relationship between the occupation rate of the stain | pollution | contamination adhering to the infrared transmission window material of the infrared sensor of this invention, and an infrared rays light receiving element output change rate.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Infrared sensor 2 Housing 4 Bottom wall 6 Infrared transmission window material 8 Hollow part 9 Sensor mounting board 10 Infrared light receiving element 12 Infrared light source 14 Optical axis 16 Upper part 18 Insulating sleeve 20 Lead wire of infrared light receiving element 22 Lead wire of infrared light source 24 Window material surface 26 Dirt
a, b Wall 2a Housing Wall X Optical axis α, θ Angle 42 Top plate 44 Heating port 46 Gotoku 48 Burner 50 Annular casing part 52 Mixing tube 54 Gas nozzle 56 Gas piping 58 Flame port 59 Flame 60 Heated object 62 Juice tray 64 Infrared ray Permeation hole 65 Control unit 66 Adjustment valve 68 Display means

Claims (5)

A housing having an infrared light path having an infrared transmission window member attached thereto, a predetermined number of infrared light receiving elements having different light receiving infrared wavelength regions provided in the housing with the light receiving surface facing the infrared transmission window member, and an infrared irradiation surface. An infrared sensor having an infrared light source provided in the housing toward the infrared transmitting window material. The infrared sensor according to claim 1, wherein a heat insulating sleeve is provided around the infrared light source. The infrared sensor according to claim 1, wherein the infrared light source irradiates an upper portion of the infrared light receiving element of the infrared transmitting window material. A housing having an infrared optical path; an infrared transmitting window member attached to the infrared optical path at a predetermined angle; and a predetermined number of mutually receiving infrared wavelengths provided in the housing with a light receiving surface facing the infrared transmitting window member An infrared sensor comprising: an infrared light receiving element having a different area; and an infrared light source attached to a housing opposite to the infrared light receiving element with respect to the infrared transmitting window material while directing an infrared irradiation surface to the infrared transmitting window material. The infrared sensor according to any one of claims 1 to 4, wherein a heating means for heating an object to be heated, a means for controlling a heating amount of the heating means, and an intensity of infrared rays emitted from the object to be heated are detected. An infrared ray light source on / off control, and a calculation control means and a display means for detecting the presence or absence of dirt on the infrared transmission window material from the output of the infrared light receiving element at the on time and at the off time, respectively, A heating apparatus that controls the amount of heating and the display means based on the intensity of infrared rays detected by a sensor.

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