JP2008241617A - Infrared intensity detection device for cooker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an infrared intensity detection device for a cooker capable of reducing an error generated when detecting the infrared intensity by avoiding a temperature rise of an optical filter. <P>SOLUTION: Optical filters 41a, 41b passable by an infrared ray having a specific wavelength band among infrared rays radiated from a cooking container heated by a heating means, and infrared receiving means 42a, 42b for detecting the intensity of the infrared ray passing the optical filters 41a, 41b are provided in an aligned state at an interval in the infrared radiation direction. An optically-transmissible member T passable by an infrared ray in a transmissible wavelength domain including a specific wavelength band is positioned on the cooking container side, and is provided in the aligned state with the optical filters 41a, 41b at an interval in the infrared radiation direction. The optical filters 41a, 41b are constituted so as to be transmissible by the infrared ray having the specific wavelength band in a state where a base material is formed of a material having a transmissible wavelength domain which is the same as the transmissible wavelength domain of the optically-transmissible member T. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an optical filter that transmits infrared rays in a specific wavelength region among infrared rays radiated from a cooking container heated by a heating unit, and an infrared light receiving unit that detects the intensity of infrared rays transmitted through the optical filter; Is provided in a state in which the optical filter is arranged at intervals in the infrared radiation direction, and the optical filter has a surface other than the specific wavelength region on a surface of a base material made of a material that transmits infrared light in a transmissive wavelength region including the specific wavelength region. The present invention relates to an infrared intensity detecting device for a cooking device that includes a reflective film that reflects infrared rays in a wavelength range.

  The infrared intensity detection device for a heating cooker is adapted to detect the intensity of infrared radiation emitted from a cooking container such as a pan heated by heating means, and based on the detected infrared intensity, For example, in order to detect the temperature of the cooking container and adjust the heating amount of the heating means so as to maintain the temperature of the cooking container at a set temperature, or to avoid an excessive temperature rise of the cooking container Although the control for stopping the heating operation of the heating means can be performed, such an infrared intensity detection device for a heating cooker has conventionally been configured as follows.

  That is, the cover member serving as a light transmitting member that transmits infrared rays radiated from the cooking container is provided on the side closer to the cooking container than the optical filter and is close to the optical filter. It was designed to prevent foreign objects such as boiled juice that overflowed from falling on the optical filter. And the base material of the said light transmissive member and the said optical filter should just satisfy the characteristic which permeate | transmits the infrared rays of the required specific wavelength range, and the material of those both is not considered in particular (For example, see Patent Document 1).

  Incidentally, what is described in Patent Document 1 includes two optical filters that pass infrared rays in two different specific wavelength bands as the optical filter, and two optical filters that correspond to the two optical filters. Infrared light receiving means is provided, and as a configuration for detecting infrared intensities in two different wavelength ranges of infrared rays emitted from the cooking container, the temperature of the cooking container is determined based on the ratio of the two infrared intensities. It can be detected.

JP 2006-207961 A

  In the conventional configuration, the light transmission member is provided in a state of being close to the optical filter, and the material of the light transmission member and the base material of the optical filter is not particularly considered. Therefore, there is a possibility that the accuracy of detecting the intensity of infrared rays may be reduced. This will be described below.

First, the configuration of the optical filter will be described.
The optical filter is intended to transmit only infrared rays in a specific wavelength range, and reflects to reflect infrared rays in a part of the wavelength ranges of infrared rays that have passed through the light transmitting member on the surface of the base material. A film is provided so that infrared rays in the specific wavelength range can pass through. That is, the optical filter is configured such that the reflective film is formed by forming a dielectric thin film in a multilayer shape on the surface of the base material by vapor deposition, for example. Among them, when the wavelength region of infrared rays to be reflected by the reflective film is widened, the number of thin film layers to be formed increases, so that it takes much time to create and the cost increases. Therefore, as the base material of the optical filter, a base material made of a material having a property of transmitting infrared light in some wavelength regions but not transmitting infrared light in other partial wavelength regions is used. Thus, the base material itself may be formed in a state where the number of thin films to be formed when the reflective film is formed is reduced by blocking the transmission of infrared rays in some wavelength regions.

Various materials such as sapphire, silicon (Si), and germanium (Ge) are conceivable as materials that can be used as the light transmissive member and the base material of the optical filter. It has the property of blocking the passage of infrared rays in a part of the wavelength region rather than transmitting the wavelength of.
For example, FIG. 8 shows wavelength vs. transmittance characteristics indicating changes in infrared transmittance with respect to changes in wavelength for sapphire at line L1 and silicon (Si) at line L2. As can be seen from FIG. 8, sapphire transmits infrared light having a shorter wavelength than about 8 μm, but does not transmit infrared light having a longer wavelength than about 8 μm, and therefore has a property of narrowing the transmissive wavelength region. Yes. On the other hand, silicon has a property that the transmissible wavelength region is wider than that of sapphire, although the transmittance varies. Silicon also has a property that its infrared transmittance is smaller than that of sapphire. Incidentally, the infrared transmittance of sapphire is about 90%, and the infrared transmittance of silicon is about 50% to 60%.

  In the infrared intensity detection apparatus for a cooking device having the above-described conventional configuration, for example, it is conceivable to use sapphire as the base material of the optical filter and silicon as the light transmission member. In this case, the reflective film of the optical filter is a reflective film that reflects infrared rays in other wavelength ranges excluding the specific wavelength range within a wavelength range shorter than about 8 μm that sapphire allows to pass. A film will be formed.

  In this configuration, the light transmitting member made of silicon transmits infrared rays over a wide wavelength range, but in the optical filter in which the base material is made of sapphire, from about 8 μm of the infrared light that has passed through the light transmitting member. However, the infrared rays on the long wavelength side do not pass through the base material of the optical filter, but are absorbed by the base material and converted into thermal energy. If it does so, the temperature of an optical filter will rise because infrared rays are absorbed by a base material.

  The light transmitting member made of silicon transmits infrared rays over a wide wavelength range compared to sapphire, but the infrared transmittance is about 50% to 60%, so 50% of incident infrared rays. Although about 60% of infrared rays are transmitted, the infrared rays that are not transmitted are absorbed into the inside and converted into thermal energy, so that the temperature of the light transmitting member is also increased by absorbing the infrared rays. Become. Further, in the above-described conventional configuration, since the light transmission member is provided in the state of being close to the optical filter, the heat of the light transmission member may be transmitted to the optical filter and the temperature of the optical filter may be increased.

  In the above description, sapphire is used as the base material of the optical filter, and silicon is used as the light transmission member. However, the present invention is not limited to this configuration, and the material of the light transmission member and the optical filter base material is not limited thereto. If it is not appropriate, this may cause the temperature of the optical filter to increase. In addition, if the configuration is such that the light transmission member is provided close to the optical filter, the temperature of the optical filter may be increased by the heat of the light transmission member.

  As a result, in the conventional configuration, the temperature of the optical filter rises, and the infrared rays based on the heat are incident on the infrared light receiving means disposed near the optical filter. And there exists a possibility that a detection error may become large due to the increase in the infrared intensity detected by the infrared light receiving means.

  An object of the present invention is to provide an infrared intensity detection device for a cooking device that can suppress an increase in the temperature of an optical filter and reduce detection errors.

An infrared intensity detection device for a cooking device according to the present invention transmits an optical filter that transmits infrared rays in a specific wavelength region of infrared rays radiated from a cooking container heated by a heating means, and transmits the optical filter. Infrared light receiving means for detecting the intensity of the infrared is provided in a state of being arranged at intervals in the infrared radiation direction,
The optical filter includes a reflective film that reflects infrared light in a wavelength region other than the specific wavelength region on a surface of a base material made of a material that transmits infrared light in a transmissive wavelength region including the specific wavelength region. And
The first characteristic configuration is that a light transmitting member that transmits infrared light in a transmissive wavelength region including the specific wavelength region is positioned closer to the cooking container than the optical filter, and extends along the infrared radiation direction. And arranged in a state of being spaced apart from the optical filter,
The optical filter is in a state in which the substrate is formed of a material having a transmissive wavelength region that is the same as or wider than the transmissive wavelength region of the light transmissive member, and the light transmission is performed by the reflective film. It exists in the point comprised in the state which reflects the infrared rays of wavelength ranges other than the said specific wavelength range among the infrared rays which permeate | transmitted the member.

  According to the first characteristic configuration, after the infrared rays radiated from the cooking container pass through the light transmission member, the infrared rays are emitted toward the optical filter, but the specific wavelength region is excluded from the infrared rays transmitted through the light transmission member. Infrared rays in other wavelength regions are reflected by the reflective film in the optical filter, and only infrared rays in the specific wavelength region are transmitted through the optical filter and irradiated toward the infrared light receiving means.

  And since the base material of the optical filter is formed of a material having a transmissive wavelength region that is the same as or wider than the transmissive wavelength region of the light transmitting member, among the transmissive wavelength regions in the base material Thus, the infrared light in the wavelength region that does not pass through the light transmitting member is absorbed inside the light transmitting member before reaching the optical filter and is not irradiated toward the optical filter. Moreover, as for the infrared rays in the wavelength region that passes through the light transmitting member in the transmissive wavelength region in the base material, the infrared rays in other wavelength regions other than the specific wavelength region in the wavelength region are reflective films as described above. It will not reach the base material because it is reflected at. In other words, since the base material transmits only infrared light in a specific wavelength range, there is little risk of temperature increase due to absorption of infrared light by the base material, and the optical filter itself is suppressed from temperature increase due to absorption of infrared light. Is done.

  As described above, infrared rays in a wavelength region other than the transmissive wavelength region of the light transmitting member among infrared rays radiated from the cooking container are absorbed by the light transmitting member, and the temperature of the light transmitting member may increase. However, since the light transmission member is provided in a state spaced apart from the optical filter along the infrared radiation direction, even if the temperature of the light transmission member may increase, the heat may be transmitted to the optical filter. Few.

As a result, the optical filter suppresses the increase in temperature due to the absorption of infrared rays by the base material and reduces the possibility of heat being transmitted from the light transmitting member, so that the infrared rays based on the heat due to the temperature increase of the optical filter are near the optical filter. Therefore, it is possible to prevent the infrared light intensity detected by the infrared light receiving means from increasing.
In addition, it is possible to facilitate the manufacture of the optical filter by configuring the light transmitting member with a material that does not transmit infrared rays in a wavelength range as wide as possible among the wavelength ranges other than the specific wavelength range.

  Therefore, according to the 1st characteristic composition, it came to be able to provide the infrared intensity detection device for cooking-by-heating equipment which can control that the temperature of an optical filter rises, and can reduce detection error.

  According to a second characteristic configuration of the present invention, in addition to the first characteristic configuration, the base material of the optical filter has an infrared transmittance in a wavelength region corresponding to the transmissive wavelength region of the light transmitting member. It is in the point formed with the material larger than the infrared transmittance of.

  According to the second characteristic configuration, in the wavelength region corresponding to the transmissive wavelength region of the light transmitting member, in other words, in the wavelength region capable of transmitting the light transmitting member, the infrared transmittance of the base material in the optical filter Is larger than the infrared transmittance of the light transmitting member.

  In other words, the infrared transmittance of a substance is defined within a range of 0% to 100%, and in the case of a commonly used material, the infrared transmittance is a value smaller than 100% even in the transmissive wavelength region. Even in the transmissive wavelength region, a part of infrared rays is absorbed inside the substance by the amount of infrared transmittance smaller than 100%.

  That is, when infrared rays pass through the light transmitting member and when infrared rays pass through the base material of the optical filter, a part of the infrared rays are absorbed, but pass through the light transmitting member. Since the infrared transmittance of the base material of the optical filter is larger than the infrared transmittance of the light transmitting member in the wavelength range where the optical filter base material can absorb, the optical filter base material absorbs the infrared light transmitted through the transmittable wavelength range. As a result, the ratio of infrared rays to be reduced becomes small, and the temperature rise of the optical filter can be further suppressed.

  Therefore, according to the second characteristic configuration, the temperature increase of the optical filter can be more easily suppressed, and the infrared intensity can be accurately detected.

  In the third feature configuration of the present invention, in addition to the first feature configuration or the second feature configuration, the base material in the optical filter is made of the same material as the light transmitting member, and the thickness of the light transmitting member is Is configured to be larger than the thickness of the substrate in the optical filter.

  According to the third characteristic configuration, since the base material in the optical filter is made of the same material as the light transmitting member, the infrared light that has passed through the light transmitting member passes through the base material of the optical filter almost as it is. In general materials that transmit infrared light, the same material is more difficult to transmit infrared light as the thickness is larger, so it becomes easier to avoid the temperature rise of the optical filter more accurately. is there.

  As a specific example, FIG. 10 shows a wavelength-to-transmittance characteristic showing a change in infrared transmittance with respect to a change in wavelength of sapphire when the thickness is changed variously, and FIG. 11 shows various changes in thickness. The wavelength vs. transmittance characteristic showing the change of the infrared transmittance with respect to the change of the wavelength of the silicon in the case of being made is shown. As can be seen from FIG. 10, as the thickness of sapphire increases, the boundary between the region that transmits infrared light and the region that does not transmit light has a property of changing to the short wavelength side. In the predetermined wavelength region, the infrared transmittance decreases as the thickness increases. As described above, the same material that transmits infrared rays has a characteristic that the greater the thickness, the more difficult it is to transmit infrared rays. In addition to sapphire and silicon, other materials have similar properties.

  Therefore, since the light transmitting member and the optical filter base material made of the same material are configured such that the thickness of the light transmitting member is larger than the thickness of the optical filter, the infrared light transmitted through the light transmitting member. Is less absorbed by the base material of the optical filter, and the optical filter absorbs infrared rays, so that the temperature rise can be more easily avoided.

  Therefore, according to the third characteristic configuration, it becomes easy to avoid the temperature increase of the optical filter more accurately, and the infrared intensity can be accurately detected.

  In addition to any of the first to third feature configurations, the fourth feature configuration of the present invention is provided with a cylindrical guide member that guides infrared rays emitted from the cooking container to the infrared light receiving means. The light transmitting member, the optical filter, and the infrared light receiving means are assembled inside the guide member in a state where the light transmitting member, the optical filter, and the infrared light receiving unit are arranged at intervals along the infrared radiation direction.

  According to the fourth characteristic configuration, the light transmitting member, the optical filter, and the infrared light receiving means are assembled in the cylindrical guide member in a state of being arranged at intervals along the infrared radiation direction. When installing the infrared intensity detector in the heating cooker, it can be handled by installing the components as they are, so that the installation work can be performed as compared with the case where each member is installed separately in the heating cooker. Can be easily performed.

  Therefore, according to the 4th characteristic structure, when installing in a heating cooker, it came to be able to provide the infrared intensity detection apparatus for heating cookers which can perform installation work easily.

  In addition to the fourth feature configuration, the fifth feature configuration of the present invention includes a plurality of the infrared light receiving means arranged in a state intersecting with the infrared radiation direction, and among infrared rays transmitted through the light transmitting member. The optical filter is provided separately for each of the plurality of infrared light receiving means in the form of transmitting infrared rays having different wavelength ranges.

  According to the fifth characteristic configuration, a plurality of infrared rays having different wavelength ranges among the infrared rays that have passed through the light transmitting member are individually arranged through the plurality of optical filters and aligned in a direction intersecting with the infrared radiation direction. It is received by the infrared light receiving means. That is, it is possible to detect the intensities of infrared rays in a plurality of wavelength ranges among the infrared rays radiated from the cooking container, using the plurality of infrared light receiving means.

  And since the light transmission member, the plurality of optical filters, and the plurality of infrared light receiving means are assembled inside the cylindrical guide member, the intensity of the infrared rays in a plurality of wavelength ranges among the infrared rays radiated from the cooking container is increased. Although it is possible to detect, when installing an infrared intensity detection device for a heating cooker in a heating cooker, it is easier to install than in the case where each member is installed in a heating cooker. It can be carried out.

  Therefore, according to the fifth feature configuration, when it is possible to detect the intensity of infrared rays in a plurality of wavelength regions among the infrared rays emitted from the cooking container, It came to be able to provide the infrared intensity detection apparatus for heating cookers which can perform installation work easily.

Hereinafter, the case where the embodiment of the infrared intensity detection device for a heating cooker according to the present invention is applied to a stove as a heating cooker will be described based on the drawings.
As shown in FIG. 1, the stove has a flat top plate 1 having a circular heating opening 1 a, a virtues 2 on which a cooking container N such as a pan can be placed spaced above the opening 1 a, It comprises a burner 30 as a heating means for heating the cooking container N placed on the virtues 2, a combustion control unit 3 for controlling the operation of the burner 30, and the like.

  The burner 30 is a Bunsen combustion type internal flame type burner. The gas nozzle 31 ejects the fuel gas G supplied through the fuel supply passage 5, the fuel gas G is ejected from the gas nozzle 31, and the fuel gas G The mixing tube 32 to which the combustion air A is supplied by the suction action accompanying the ejection of the gas and the plurality of flame ports 33 for ejecting the air-fuel mixture to the inner peripheral portion are provided, and the air-fuel mixture is supplied from the mixing tube 32. An annular burner main body 34 and the like are provided, and the burner 30 is provided below the opening 1a.

  In the burner 30, the mixture of the fuel gas G and air A supplied from the mixing pipe 32 into the burner body 34 is ejected in a substantially horizontal direction from the flame port 33 toward the center of the burner body 34. The mixture of the fuel gas G and air A thus burned burns, and a flame F is formed upward through the opening 1a.

  The fuel supply path 5 is provided with a fuel supply intermittent valve 6 for intermittently supplying the fuel gas G to the gas nozzle 31, and a fuel supply amount adjusting valve 7 for adjusting the supply amount of the fuel gas G to the gas nozzle 31, Below the burner main body 34 of the burner 30, a juice receiving tray 8 is provided for receiving boiled food that has fallen through the opening 1a.

  Further, the stove has an infrared intensity detection device as an infrared intensity detection device that is located on the lower side of the top plate 1 and located in the center of the soup pan 8 and detects the intensity of infrared rays emitted from the cooking container N. The temperature detection part 50 as a temperature detection means which detects the temperature of the container N for cooking based on the intensity | strength of the infrared rays detected by the part 40 and the infrared intensity detection part 40 is provided.

The infrared intensity detection unit 40 is configured to detect the infrared intensity for each of two different specific wavelength ranges in the infrared rays emitted from the cooking container N, and the temperature detection unit 50 is connected to the infrared intensity detection unit 40. The temperature of the cooking container N is detected on the basis of the ratio of the infrared intensity for each of the two specific wavelength regions detected.
Furthermore, the infrared intensity detection unit 40 is configured to detect the infrared intensity in a wavelength region set within a range where the radiation intensity from the flame of the burner 30 is small in the infrared wavelength range.

  As shown in FIG. 2, the infrared intensity detector 40 passes through optical filters 41 a and 41 b that pass infrared rays in a specific wavelength region of infrared rays emitted from the cooking container N, and the optical filters 41 a and 41 b. Infrared light receiving elements 42a and 42b as infrared light receiving means for detecting the intensity of the infrared light are provided in a state of being arranged at intervals in the infrared radiation direction, and allow passage of infrared light in a transmissive wavelength region including a specific wavelength region. The window member 46 as the light transmissive member T is disposed on the cooking container N side with respect to the optical filters 41a and 41b and is arranged in a state of being aligned with the optical filters 41a and 41b with an interval in the infrared radiation direction. Yes.

  Further, a cylindrical guide member 47 for guiding the infrared rays radiated from the cooking container N to the infrared light receiving elements 42a and 42b is provided, and the guide members 47 are arranged at intervals along the infrared radiation direction. In the state, the window member 46, the optical filters 41a and 41b, and the infrared light receiving elements 42a and 42b are assembled. In addition, two infrared light receiving elements 42a and 42b are provided in a state of being arranged in a direction intersecting with the infrared radiation direction, and two infrared rays having different wavelength ranges among the infrared rays having passed through the window member 46 are passed. Optical filters 41a and 41b are provided separately for the two infrared light receiving elements 42a and 42b.

  In other words, as shown in FIG. 2, the opening is provided in a casing 43 that includes a light incident opening 44 and is configured by a light-shielding member so as to surround the periphery except for the opening 44. The two infrared detection elements 42a and 42b are arranged side by side on the pedestal 48 so that the infrared rays incident through 44 can be detected, and one optical filter is provided at a portion where the infrared rays are incident on the one infrared detection element 42a. 41a is provided, and the other optical filter 41b is provided in a portion where infrared rays are incident on the other infrared detection element 42b. In the casing 43, a signal processing unit 45 for processing output signals of the two infrared detection elements 42a and 42b is provided.

  An outer cylindrical member 47A formed in a hollow cylindrical shape with a light-shielding member is provided so as to surround the upper side of the opening 44 in the casing 43. The inside of the outer cylindrical member 47A and the opening in the casing 43 are provided. 44, and an inner cylinder member 47B is provided which forms two guide paths Q1 and Q2 for guiding the infrared rays toward the two infrared detection elements 42a and 42b separately. The outer cylinder member 47A and the inner cylinder member 47B constitute the guide member 47.

  A window member 46 is provided at the upper end portion of the outer cylindrical member 47A so as to cover the inside of the outer cylindrical member 47A. The window member 46 is configured to transmit infrared rays radiated from the cooking container N into the outer cylindrical member 47A. It also has a function to prevent and protect boiled juice and other things from falling on the optical filters 41a and 41b.

  The outer cylindrical member 47A introduces infrared rays radiated from the cooking container N and transmitted through the window member 46 into the casing 43, and is connected to the opening 44 of the casing 43 so that light does not enter from the lateral outer side. It becomes the composition which is done. And other than cooking container N, ie, the infrared rays radiated from Gotoku 2 and burner main body 34, are provided in a long shape along the vertical direction so that it is difficult to be introduced toward the inside of casing 43.

  The inner cylindrical member 47B has a pair of left and right light inlets 49 formed in the upper horizontal plane portion, and a first infrared ray guided through the outer cylindrical member 47A is guided to one infrared detecting element 42a. One guide path Q1 is formed, and is positioned in the first guide path Q1 so as to support the optical filter 41a in a state where it is housed. Further, a second guide path Q2 for guiding the infrared guided through the outer cylindrical member 47A toward the other infrared detecting element 42b is formed, and the second optical path Q2 is positioned on the second guide path Q2 so as to guide the other optical. The filter 41b is supported in a built-in state.

  The outer cylindrical member 47A and the inner cylindrical member 47B are made of a light-shielding member, and are configured to prevent the entry of infrared rays from the outside. In order to prevent the temperature from rising, the inner peripheral surface of the outer cylindrical member 47A and the upper horizontal surface portion where the light inlet 49 in the inner cylindrical member 47B is formed have a highly reflective surface so as to reflect infrared rays. It is comprised so that.

  The infrared intensity detection unit 40 is configured such that the outer cylinder member 47A, the inner cylinder member 47B, the window member 46, the optical filters 41a and 41b, and the infrared light receiving elements 42a and 42b are connected to the casing 43. When the infrared intensity detector 40 is installed on a stove, the articles are installed in a state of being assembled in a unit shape in advance.

  As shown in FIG. 1, the infrared intensity detection unit 40 is provided in a state of being vertically inserted through an opening formed in the soup pan 8, but the soup pan is difficult to transmit heat from the soup pan 8. On the other hand, it becomes the structure with which the heat insulating material D is mounted | worn. In addition, a temperature rise suppression means such as a cooling fan may be provided so that the infrared light receiving elements 42a and 42b do not rise in temperature.

  The optical filters 41a and 41b are configured to transmit infrared rays in a specific wavelength region in a state where the base material K is formed of a material having the same transmissive wavelength region as the transmissive wavelength region of the window member 46. Has been. Specifically, the base material K of the optical filters 41a and 41b is made of the same material as the window member 46, and as shown in FIG. 2, the thickness of the window member 46 is the base material K of the optical filters 41a and 41b. It is comprised so that it may become larger than the thickness of.

  In this embodiment, as one of the specific wavelength ranges detected by each of the infrared light receiving elements 42a and 42b, a wavelength range within the range of 8.0 μm to 12.0 μm is set as a detection target. In addition, silicon (Si) is used as the material of the base material K and the window member 46 of the optical filters 41a and 41b. The reason why silicon is used in this way is that if it is silicon, it transmits infrared rays in a wavelength range of 8.0 μm or more and 12.0 μm or less.

  When silicon is used as the base material K of the optical filters 41a and 41b, as shown in the wavelength-to-transmittance characteristics of FIG. 11, silicon has a lower infrared transmittance as the thickness increases in a predetermined wavelength region. It has the property of doing. Accordingly, when silicon is used as the material of the base material K and the window member 46 of the optical filters 41a and 41b, if the thickness of the light transmitting member T is made larger than the thickness of the base material K, the infrared light transmitted through the window member 46 is transmitted to the optical filter. There is little risk of being absorbed by the base material K of 41a and 41b, and it becomes easy to avoid the temperature rise due to the optical filters 41a and 41b absorbing infrared rays.

  Therefore, silicon is used as the material of the base material K and the window member 46 of the optical filters 41a and 41b, and the thickness of the window member 46 is set larger than the thickness of the base material K.

  Further, as shown in FIG. 7, the optical filters 41a and 41b are provided with a window member 46 on the surface of a base material K made of a material that transmits infrared rays in a specific wavelength range made of a material selected as described above. A reflection film h that reflects infrared rays other than the specific wavelength region out of the transmitted infrared rays is provided, and the infrared rays in the specific wavelength region are allowed to pass. The reflection film h is formed by, for example, forming a dielectric thin film in a multilayer shape by vapor deposition and reflecting infrared rays in a predetermined wavelength range. The optical filters 41a and 41b having such a configuration are configured to transmit only infrared rays in a specific wavelength region, for example, as illustrated in FIG.

  As one of the specific wavelength ranges detected by each of the infrared light receiving elements 42a and 42b, a wavelength range shorter than 8.0 μm, for example, a range of 2.0 μm to 2.4 μm, and 3 If the thickness is set in the range of 1 μm or more and 4.2 μm or less, sapphire can be used as the material of the base material K and the window member 46 of the optical filters 41a and 41b.

  In the case of using sapphire, as shown in the wavelength-to-transmittance characteristics of FIG. Since the thickness of the window member 46 is set to be larger than the thickness of the base material K as in the case of silicon, the infrared light transmitted through the window member 46 is transmitted to the optical filter 41a. , 41b is less likely to be absorbed by the base material K, and the optical filter 41a, 41b can easily avoid an increase in temperature by absorbing infrared rays.

In addition to silicon and sapphire, examples of materials that can be used as the base material K and the window member 46 of the optical filters 41a and 41b include germanium (Ge), CaF ₂ (calcium fluoride), and MgF ₂ (fluorine). Various materials such as magnesium halide), ZnSe (zinc selenide), Y ₂ O ₃ (yttrium oxide), and SiO ₂ (synthetic quartz) can be used.

Next, how to set the two wavelength ranges will be described.
FIG. 3 shows a spectral spectrum of the infrared radiation intensity when the temperature changes when a standard cooking container N painted black on a metal surface is heated in the range from room temperature (25 ° C.) to about 300 ° C. Data are shown. As is apparent from this figure, infrared rays are radiated in the wavelength range of 1.5 μm or more and several tens of μm or less at the temperature when the burner 30 is burning, for example, from room temperature to 300 ° C. For example, it has sufficient radiation intensity that can be detected by various infrared sensors within a range of 3.5 μm or more and 15 μm or less.

FIG. 4 shows the infrared radiation intensity spectrum distribution emitted from the flame formed by the actual burner 30. As is clear from this figure, the infrared wavelength range is 1.5 μm or more and 1.8 μm or less, 2.0 μm or more and 2.4 μm or less, 3.1 μm or more and 4.2 μm or less. In the range of 8.0 μm or more and 12.0 μm or less, there is little infrared radiation from the flame.
Therefore, if the two wavelength ranges are set within a range in which the infrared radiation from the flame of the burner 30 is small in the infrared wavelength range, the radiation from the cooking container N is less affected by the infrared radiation from the flame. It is possible to accurately detect the intensity of infrared rays.

  As the two infrared detecting elements 42a and 42b for detecting the infrared intensity in the wavelength range as described above, Ge or InGaAs is used as an infrared cell, PbS or PbSe is used as an infrared cell, and HgCdTe is used. Various things, such as what was used as an infrared cell, can be utilized. In addition to the above materials, a power raising element, a thermopile, or the like can be used.

Next, a process for obtaining the temperature of the cooking container N by the temperature detection unit 50 will be described. In the following description, the two wavelength regions are denoted by λ1 and λ2. Incidentally, the wavelength region λ2 is longer than the wavelength region λ1.
FIG. 5 shows the temperature of the object to be heated (cooking container N) obtained in advance by experiment and the output values (corresponding to the infrared intensity) for each of the two wavelength regions λ1 and λ2 in the infrared intensity detector 40. Show the relationship. Incidentally, the relationship shown in FIG. 4 is obtained by using a heated object having an emissivity (radiation rate) of 0.92.

  FIG. 6 shows an output ratio (the aforementioned ratio) between the temperature of the object to be heated (cooking container N) and the output value corresponding to the wavelength region λ1 and the output value corresponding to the wavelength region λ2 in the infrared intensity detection unit 40. (Corresponding to the infrared intensity ratio) (hereinafter may be referred to as a relationship between temperature and infrared intensity ratio). Incidentally, the relationship between the temperature and the infrared intensity ratio shown in FIG. 6 is obtained as follows.

That is, for each of a plurality of cooking containers having different emissivities, the temperature of the cooking container is varied to a plurality of temperatures, and the output ratio is obtained for each of the plurality of temperatures. Then, based on the data obtained for a plurality of cooking containers having different emissivities ε, an approximate expression of the relationship between the temperature and the output ratio is obtained, and the obtained approximate expression is expressed as a relationship between the temperature and the infrared intensity ratio. It is said.
Therefore, the relationship between the temperature-to-infrared intensity ratios of the respective cooking containers N having different emissivities ε can be made into one common temperature-to-infrared intensity ratio relationship. Further, the relationship of the temperature to infrared intensity ratio as shown in FIG. 6 obtained as described above is stored in the storage unit (not shown) of the temperature detection unit 50.

  Then, the temperature detection unit 50 obtains and stores an output ratio (corresponding to the infrared intensity ratio) between the output value corresponding to the wavelength region λ1 and the output value corresponding to the wavelength region λ2 in the infrared intensity detection unit 40. The temperature of the cooking container N is determined from the relationship between the temperature and the infrared intensity ratio. By taking such a ratio of output values, the temperature of the cooking container N can be accurately detected without depending on the emissivity of the cooking container N.

  Information on the temperature obtained by the temperature detection unit 50 is output to the combustion control unit 3, and the combustion control unit 3 performs the fuel supply intermittent valve 6, based on the temperature obtained by the temperature detection unit 50, By controlling the fuel supply amount adjusting valve 7 or the like, for example, the fuel supply amount adjusting valve 7 is controlled to adjust the combustion amount of the burner 30 so that the temperature of the cooking container N is maintained at a set temperature, or cooking. In order to avoid an excessive temperature rise of the container N, processing such as operating the fuel supply intermittent valve 6 to stop the heating operation of the burner 30 is performed.

[Another embodiment]
Next, another embodiment will be described.

  (1) In the said embodiment, the said base material in the said optical filter is comprised with the same material as the said light transmissive member, and the thickness of the said light transmissive member is larger than the thickness of the said base material of the said optical filter. However, the present invention is not limited to such a configuration, and the optical filter has a material having a transmissive wavelength region wider than the transmissive wavelength region of the light transmissive member. It may be formed by.

  When the base material of the optical filter is formed of a material having a transmissive wavelength region wider than the transmissive wavelength region of the light transmissive member in this manner, as shown in FIG. The material may be made of a material whose infrared transmittance in a wavelength region corresponding to the transmissive wavelength region of the light transmitting member is larger than the infrared transmittance of the light transmitting member. That is, the light transmitting member having the wavelength-to-transmittance characteristic indicated by the line L3 in FIG. 12 is configured by the base material having the wavelength-to-transmittance characteristic indicated by the line L4 in FIG.

  (2) In the above embodiment, the light transmitting member T is configured by the window member 46 that transmits infrared light as it is, but instead of such a configuration, as shown in FIG. The light transmitting member T may be configured by a condensing lens 60 that condenses infrared light emitted from the container and guides the infrared light toward the infrared light receiving elements.

(3) In the above embodiment, as the process for obtaining the temperature by the temperature detection means, the temperature of the cooking container is obtained based on the ratio of the infrared intensity for each of the two wavelength ranges. Instead, it may be configured as follows.
For example, by using a plurality of cooking containers having different emissivities, the temperature of the cooking container is changed to a plurality of temperatures, and the infrared intensity for each of the plurality of wavelength ranges is obtained for each of a plurality of temperatures. The infrared intensity for each of the plurality of wavelength ranges thus obtained is stored as map data in a state corresponding to each of the plurality of temperatures. Then, from the map data, an infrared intensity relationship that matches or is similar to the infrared intensity relationship for each of the plurality of wavelength ranges detected by the infrared intensity detection means, and the determined infrared intensity relationship The temperature corresponding to is obtained, and the obtained temperature is set as the temperature of the cooking container. Incidentally, in this case, the plurality of wavelength ranges may be two wavelength ranges as in the above embodiments, or may be three or more wavelength ranges.

  In addition, one wavelength range is set as the wavelength range, and the infrared intensity for the wavelength range is stored in map data in a state corresponding to a plurality of temperatures. It is good also as a structure which calculates | requires the temperature of the container for cooking from the detected value of infrared intensity.

  (4) In the above embodiment, the infrared intensity detection means includes two infrared detection elements 42a and 42b that individually detect the infrared rays that have passed through the two optical filters 41a and 41b, and radiates from the cooking container N. However, in place of such a configuration, two optical filters act alternately on one infrared detection element. Thus, the positions may be switched, and the infrared intensity in different wavelength ranges may be detected using the detection value of the infrared detection element in each of the switched states. Further, as a configuration comprising three or more infrared detection elements and optical filters arranged side by side, a configuration in which infrared rays in three or more different specific wavelength ranges are detected separately and the temperature of the cooking container is detected based on the detection information It is good.

(5) In the above embodiment, the heating means is constituted by an internal flame type burner that injects and burns the air-fuel mixture inward from the annular burner body, but the air-fuel mixture is directed upward and outward. You may comprise as a stove provided with the bunsen combustion type burner to eject.
That is, as shown in FIG. 14, the burner 30 is provided below the opening 1 a formed in the top plate 1 in a state having a flame port 33 for injecting the air-fuel mixture upward and burning it, An annular juice receiving tray 8 is provided on the outer peripheral portion of the burner 30, and an infrared intensity detection unit 40 having the same configuration as that of the first embodiment is provided via a heat insulating material D in a portion inclined upward and outside the juice receiving tray 8. It is good also as a structure to be made.

  (6) In the above embodiment, the infrared intensity detecting means is configured to detect the intensity of infrared rays emitted from the cooking container through the heating opening formed in the top plate. In addition to such a configuration, a light transmitting window is formed on the top plate at the side of the heating opening, and the infrared intensity detecting means is used for cooking through the light transmitting window. It is good also as a structure so that the intensity | strength of the infrared rays radiated | emitted from the container and permeate | transmitted the optical filter may be detected. Therefore, in this configuration, the light transmitting window formed on the top plate corresponds to the light transmitting member.

  (7) In the above embodiment, a gas combustion burner is used as the heating means. However, the heating means is not limited to a burner. For example, a heating lamp using a halogen lamp that emits red heat, an electric resistance wire is used. You may comprise by an electric heating part, such as a thing using the built-in sheathed heater or a thing using a magnetic field generating coil which performs electromagnetic induction heating (usually called "IH").

Schematic configuration diagram of the stove Longitudinal sectional view of infrared intensity detection means The figure which shows the spectrum data of the infrared radiation intensity radiated | emitted from the container for cooking Figure showing the infrared radiation intensity spectrum distribution emitted from the flame The figure which shows the relationship between the temperature of a to-be-heated material, and the output of an infrared intensity detection part The figure which shows the relationship between the temperature of to-be-heated material and the output ratio of an infrared intensity detection part Cross section of optical filter Diagram showing transmittance versus wavelength characteristics of sapphire and silicon The figure which shows the wavelength vs. transmittance characteristic of the optical filter Diagram showing transmittance characteristics of sapphire versus wavelength Diagram showing transmittance versus wavelength characteristics of silicon The figure which shows the wavelength versus the transmittance | permeability characteristic of another embodiment Vertical sectional view of infrared intensity detecting means of another embodiment Schematic configuration diagram of a stove according to another embodiment

Explanation of symbols

41a, 41b Optical filters 42a, 42b Infrared light receiving means 47 Guide member N Cooking container T Light transmitting member

Claims (5)

An optical filter that transmits infrared rays in a specific wavelength region out of infrared rays radiated from the cooking container heated by the heating means, and an infrared light receiving means that detects the intensity of the infrared rays that have passed through the optical filter are infrared radiation. It is provided in a state of being lined up at intervals in the direction,
The optical filter includes a reflective film that reflects infrared light in a wavelength region other than the specific wavelength region on a surface of a base material made of a material that transmits infrared light in a transmissive wavelength region including the specific wavelength region. An infrared intensity detection device for a cooking device,
A light transmissive member that transmits infrared light in a transmissive wavelength region including the specific wavelength region is positioned closer to the cooking container than the optical filter, and is spaced from the optical filter along the infrared radiation direction. Provided in a state of being lined up apart,
The optical filter is in a state in which the substrate is formed of a material having a transmissive wavelength region that is the same as or wider than the transmissive wavelength region of the light transmissive member, and the light transmission is performed by the reflective film. An infrared intensity detection device for a heating cooker configured to reflect infrared light in a wavelength region other than the specific wavelength region out of infrared light transmitted through a member.   The base material of the optical filter is formed of a material having an infrared transmittance greater than that of the light transmissive member in a wavelength region corresponding to the transmissive wavelength region of the light transmissive member. An infrared intensity detecting device for a cooking device as described.   The base material in the optical filter is made of the same material as the light transmissive member, and the thickness of the light transmissive member is larger than the thickness of the base material in the optical filter. Item 3. An infrared intensity detection device for a cooking device according to item 1 or 2.   A cylindrical guide member is provided for guiding the infrared radiation radiated from the cooking container to the infrared light receiving means, and the light is arranged inside the guide member at intervals along the infrared radiation direction. The infrared intensity detection device for a heating cooker according to any one of claims 1 to 3, wherein the transmission member, the optical filter, and the infrared light receiving means are assembled.   A plurality of infrared light receiving means are provided in a state in which the infrared light receiving means are arranged in a direction intersecting with the infrared radiation direction, and the infrared light receiving means is configured to transmit infrared rays having different wavelength ranges among infrared rays transmitted through the light transmitting member. The infrared intensity detecting device for a cooking device according to claim 4, wherein the optical filter is provided separately for each.

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