JPH02307024A - Far infrared sensor - Google Patents

Abstract

PURPOSE:To allow quantitative measurement with far IR rays of a specific wavelength by constituting the sensor of a case having a far IR filter, a thermally expanding member and a pressure-sensitive element. CONSTITUTION:The heat absorber of the thermally expanding member 6 absorbs the far IR rays of the specific wavelength if a certain far IR ray transmits the far IR filter and a transparent plate 3. Liquid paraffin to serve as an expanding liquid is then expanded by the absorbed heat. The thermally expanding member 6 is then sealed into an elastic film 5 the upper aperture of which is closed by the transparent plate 3. Since the side faces of the elastic film 5 are enclosed by a case body 2, the pressure in the expanding part of the member 6 is fully applied downward and is transmitted through the elastic film 5 to conductive rubber 8 of the pressure-sensitive element 7. The elastic film 5, therefore, applies the pressure to the rubber 8 and the resistance value of the rubber 8 changes. The change in the resistance value is detected between electrode plates 9 and 10. The rubber 8 is constituted as a part of a bridge circuit, etc., assembled to the outside via lead wires 11, 12, by which the above- mentioned change is detected as a change in voltage.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a far-infrared sensor that detects the intensity of far-infrared rays.

[Conventional technology 1] In recent years, far infrared rays have become widely used in fields such as cooking, medicine, and housing. There are two types of thermal infrared sensors: thermal infrared sensors whose temperature changes, and quantum far infrared sensors that directly detect far infrared rays as photons.Thermal infrared sensors include thermocouples, bolometers, and Golays. As the latter type of infrared sensor, photovoltage sensors using PbS, P, bSe, etc. are known, and these are configured as semiconductor infrared sensors.

[Problem that the invention seeks to solve]

However, among the conventional far-infrared sensors mentioned above, although the former thermal type far-infrared sensors have flat wavelength characteristics, they are not suitable for measuring far-infrared rays of a specific wavelength, and are not suitable for use with radiation thermometers, etc. Limited to applications.

On the other hand, the latter quantum far-infrared sensor has the advantage of being able to measure the presence or absence of far-infrared rays in a specific wavelength band that matches the sensor characteristics, so it can be used in a variety of ways. Widely used as sensors, infrared switches, etc.

However, with conventional technology, although it is possible to detect the presence or absence of far infrared rays with a specific wavelength, it is difficult to quantitatively determine the amount of far infrared rays with a specific wavelength, the strength of the effect, etc. There is a problem. For this reason, for example, the temperature distribution of cooking machines, etc.

It was not possible to quantitatively measure the heat distribution, the effect of infrared rays, etc., and it was not possible to analyze far infrared rays to judge whether the product was baked or whether it was upgraded.

The present invention has been made in view of the above-mentioned prior art, and an object of the present invention is to provide a far-infrared sensor that can quantitatively measure far-infrared rays of a specific wavelength, and thus can be easily applied to cooking machines and the like.

[・Means to solve the problem]

In order to solve the above-mentioned problems, the configuration adopted by the present invention includes a case having a far-infrared filter that transmits far-infrared rays, and a case that is filled in the case and absorbs the far-infrared rays that have passed through the far-infrared filter. The device is composed of a thermal expansion member that expands as a result of the expansion, and a pressure sensing element that is provided in the case and detects the pressure caused by the expansion of the thermal expansion member and derives it as a change in the amount of electricity.

[Effect]

With the above configuration, the amount of far infrared rays and the strength of effect 1 can be quantitatively measured by converting the amount of expansion of the thermal expansion member into the amount of electricity of the pressure sensitive element and detecting the far infrared rays.

【Example〕

FIG. 1 shows a first embodiment of the present invention. In the figure, 1 is a case of this embodiment, and the case 1 is made of a non-expandable material, such as a ceramic material, and has a bottom portion 2A and a flange portion 2B. It is composed of a case body 2 having a cylindrical bottom shape and a transparent plate 3 which is mainly made of transparent glass material and covers the opening side of the case body 2.

4 is a material with high transmittance of far infrared rays for a specific wavelength;
For example, a far-infrared filter 4 made of Ge, an alloy of Ge and Cu, etc. is shown, and the far-infrared filter 4 is embedded in the transparent plate 3 so as to close the opening of the case body 2.

Reference numeral 5 denotes an elastic membrane made of an elastic material and formed into a bottomed cylindrical shape consisting of a bottom portion 5A and a flange portion 5B. An internal space 5C is defined by being crimped around the entire circumference and closed by the transparent plate 3.

Reference numeral 6 denotes a thermal expansion member filled in the internal space 5C of the elastic membrane 5, and the thermal expansion member 6 is made of a polymer compound with good heat absorption rate as a heat absorber and a wax such as liquid paraffin as an expansion liquid. It consists of a mixture of Here, as the heat absorber, various polymer compound materials are applied depending on the absorption wavelength of far infrared rays, and for example, melamine resin is used as a material that absorbs far infrared rays of 6 to 100 lum, 4
Polypropylene is used as a material that absorbs far infrared rays of μm. The expansion liquid is configured to thermally expand according to the amount of heat absorbed by the heat absorber.

Reference numeral 7 denotes a pressure sensing element located within the bottom 2A of the case body 2 and sandwiched between the bottom 5A of the elastic membrane 5, and the pressure sensing element 7 is moved by the applied pressure (load). A conductive rubber 8 whose electrical resistance characteristics or voltage characteristics change, and the top of the conductive rubber 8.

An electrode plate 9 provided on the lower surface to sandwich the conductive rubber 8
．． 10, and a lead wire 11 connected to the electrode plate 9.10.
．． It consists of 12. The conductive rubber 8 receives a load due to the expansion of the thermal expansion member, and generates an output corresponding to the load.

In the figure, reference numeral 13 denotes a heat insulating material that covers the outer periphery of the case body 2, and the heat insulating material 13 is made of, for example, foamed resin.

The present embodiment is configured as described above, and its operation will be described next.

Now, a certain far infrared ray is filtered through a far infrared filter 4. When transmitted through the transparent plate 3, the heat absorber of the thermal expansion member 6 absorbs the far infrared rays of a specific wavelength, and the liquid paraffin serving as the expansion liquid expands due to the absorbed heat. Thermal expansion member 6 is enclosed within elastic membrane 5 whose upper opening is closed by transparent plate 3, and
Since the side surface of the elastic membrane 6 is surrounded by the case body 2, all the pressure of the expanded portion of the thermal expansion member 6 is applied downward and is transmitted to the conductive rubber 8 of the pressure sensitive element 7 through the elastic membrane 5. Therefore, the elastic membrane 5 applies pressure to the conductive rubber 8, the resistance value of the conductive rubber 8 changes, and the change in resistance value is detected between the electrode plates 9 and 10.

Therefore, by configuring the conductive rubber 8 as a part of a bridge circuit (not shown) or the like built externally via the lead wires 1.1.12, it is possible to detect the voltage change.

As described above, in this embodiment, by incorporating the thermal expansion member 6 and the pressure-sensitive element 7 into the case body 2 and configuring it as a far-infrared sensor, far-infrared rays of a specific wavelength can be detected. Since the expansion coefficient of the thermal expansion member 6 depends on the strength of far infrared rays, far infrared rays can be quantitatively measured by using a material that thermally expands only for far infrared rays of a specific wavelength for the thermal expansion member 6. be able to.

For example, when measuring the temperature distribution, calorific value distribution, and far-infrared effect 1 strength of a cooking machine, etc., the far-infrared sensor of this embodiment is suitable because it can measure the intensity of far-infrared rays at a specific wavelength. It is.

Moreover, by changing the material of the far-infrared filter 4 to a material that transmits the specific wavelength of the far-infrared rays to be detected, and by adjusting the polymer compound of the thermal expansion member 6 to match the absorption wavelength of the far-infrared rays to be detected, It is possible to detect far-infrared rays in a narrow wavelength range. For example, if nylon is used instead of melamine as the heat absorber of the thermally expandable member 6, it can absorb wavelengths in a narrow range of 6 to 8 μm, which makes it possible to detect far-infrared rays at more specific wavelengths than with melamine. I can do it. Further, if a polymer compound capable of absorbing far infrared rays in a wide range is used as the heat absorber of the thermal expansion member 6, far infrared rays of arbitrary wavelengths can also be detected.

Next, a second embodiment of the present invention will be described based on FIG. 2. Note that the same components as in the first embodiment shown in FIG.

Reference numeral 21 denotes a pressure sensitive element of this embodiment which replaces the pressure sensitive element 7 according to the first embodiment, and the pressure sensitive element 21 is made of a piezoelectric ceramic 2.
2, electrode plates 23 and 24 arranged to sandwich the top and bottom of the piezoelectric ceramic 22, and the electrode plate 23 and the elastic membrane 5.
A dish-shaped plate spring 25 provided between the bottom 5A of the ! and the lead connected to the electrode plate 23, 24! 126.27
It is composed of.

When the thermal expansion member 6 thermally expands, the pressure sensitive element 21 of this embodiment transmits the pressure to the leaf spring 25.
By transmitting the load change No. 5 to the piezoelectric ceramic 22, the voltage output characteristic of the piezoelectric ceramic 22 changes due to the piezoresistive effect.

Next, to explain the operation of the second embodiment, when far infrared rays pass through the far infrared filter 4, all the pressure of the expanding part of the thermal expansion member 6 that absorbs the far infrared rays and expands is applied downward, and the elastic Leaf spring 25 of pressure sensitive element 21 through membrane 5
and is transmitted to the piezoelectric ceramic 22. As a result, piezoresistance is generated in the piezoelectric ceramic 22, and the electrode plate 23.2
A change in resistance is detected between 4 and outputted as a signal such as resistance or voltage to the outside from lead wires 26 and 27.

Note that the pressure-sensitive element of the present invention may be a semiconductor piezoelectric element, a pressure-sensitive conductive rubber, or the like instead of the conductive rubber or piezoelectric ceramic shown in the embodiments.

〔Effect of the invention〕

As described in detail above, according to the present invention, there is provided a thermal expansion member that expands by absorbing far infrared rays in a case having a far infrared filter, and a piezoelectric material that changes the amount of electricity when subjected to the expansion pressure of the thermal expansion member. By providing an element, the intensity of far infrared rays can be measured quantitatively, and various far infrared rays can be measured by selecting a far infrared filter and a thermal expansion member, so it is possible to measure the specific wavelength that you want to measure. When measuring far-infrared rays, you need to select an infrared filter or thermal expansion member that matches this wavelength (the amount of far-infrared rays that was impossible with conventional technology).

Effect 1 Strength etc. can be understood quantitatively.

[Brief explanation of the drawing]

1 and 2 relate to embodiments of the present invention, FIG. 1 is a longitudinal cross-sectional view of a far-infrared sensor according to the first embodiment, and FIG. 2 is a longitudinal cross-section of a far-infrared sensor according to the second embodiment. Show the diagram. l...Case, 2...Case body, 3...Transparent plate, 4...Far infrared filter, 5...Elastic membrane, 6...
- Thermal expansion member, 7, 21... Pressure sensitive element, 8... Conductive rubber, 13... Heat insulating material, 22... Piezoelectric ceramic. Patent Applicant Japan Electronics Co., Ltd. Agent Patent Attorney Kazuhiko Hirose Figure 1

Claims (1)

[Claims] a case having a far-infrared filter that transmits far-infrared rays; a thermal expansion member that is filled in the case and expands by absorbing the far-infrared rays that have passed through the far-infrared filter;
A far-infrared sensor comprising a pressure sensitive element provided in the case and configured to detect pressure due to expansion of the thermal expansion member and derive it as a change in electrical quantity.