JP2014089108A - Non-contact temperature sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a non-contact temperature sensor capable of preventing the increase in man-hour and cost at the manufacturing time, the reduction in productivity, and the deterioration in work environment and natural environment and also capable of suppressing a sensitivity error and a reduction in sensitivity.SOLUTION: A non-contact temperature sensor 100 includes: a guide cylinder 30 provided so as to define a visual field range of the temperature detection by an infrared ray detection heat-sensitive element 15 in a heat source 7A. The guide cylinder 30 includes: an opening P; and a body part 31 including sloped wall parts 31a to 31b to extend slope-wise against the perpendicular direction of a light receiving surface N toward the light receiving surface N arranged with the infrared ray detection heat-sensitive element 15 from the opening P, and further includes a light-shielding space W formed by the body part 31 around a light receiving range Q including the infrared ray detection heat-sensitive element 15.

Description

  The present invention relates to a non-contact temperature sensor that measures the temperature of a heat source (heating element) in a non-contact manner.

  In general, a non-contact temperature sensor for non-contact measurement of the temperature of a heat source detects a temperature rise of an infrared absorption film that absorbs infrared rays radiated from the heat source by a thermal sensor for infrared detection, and is based on the amount of heat of the emitted infrared rays. And measure the temperature of the heat source. The thermal element for infrared detection has a temperature characteristic in which the electrical characteristics change according to the amount of heat received, and not only by the amount of infrared heat absorbed by the infrared absorption film, but also by the amount of heat given to the infrared detection thermal element by the external environment. However, its electrical characteristics change. For this reason, such a non-contact temperature sensor usually detects the amount of heat flowing in and out between the external environment and the infrared detection thermal element in addition to the infrared detection thermal element, and the infrared detection thermal element. There is also provided a temperature compensating thermosensitive element for correcting the measurement result.

  As such a non-contact temperature sensor, for example, Patent Document 1 discloses a resin film (infrared ray) in which a thermal sensing element for infrared detection is fixed to the bottom side of a cylindrical holding body (for example, made of metal such as aluminum) having an opening. What is provided with an absorption film) is described. In this non-contact temperature sensor, an opening of a cylindrical holder provided in front of the infrared absorption film is disposed so as to face a heat source (such as a heat fixing roller of a copying machine) that is a temperature detection target. The

Japanese Patent No. 4415045

  Here, the cylindrical holder in the conventional non-contact temperature sensor is an infrared light guide radiated from the heat source, defines the direction of temperature detection, and the temperature detection field range (temperature detection field range in the heat source). ) To function as an infrared “guide tube”. Usually, infrared rays are radiated in all directions from each point on the surface of the heat source, and a part of them is incident on the inside from the opening of the guide tube. Of the infrared rays incident on the inside of the guide tube, the component that directly reaches the infrared absorption film and the component that is reflected by the inner wall of the guide tube and indirectly reaches the infrared absorption film are absorbed by the infrared absorption film. In addition, the sum of the energy of both components contributes to the temperature increase of the infrared absorption film, and can affect the sensitivity of the non-contact temperature sensor.

  Among these infrared components, the intensity (line bundle) of the infrared component reflected by the inner wall of the guide tube is affected by the reflection characteristics of the inner wall, and the reflection characteristics change depending on the surface state of the inner wall (variation). ) Furthermore, it also fluctuates due to the occurrence of rust or dirt on the inner wall. Therefore, the infrared component reflected by the inner wall of the guide tube can be a major factor in non-contact temperature sensor sensitivity variations and aging.

  In order to suppress sensitivity errors and fluctuations due to the infrared component reflected by the inner wall of the guide tube, various methods for absorbing and not reflecting the infrared light incident on the inner wall of the guide tube have been proposed. . For example, also in the above-mentioned Patent Document 1, an anodizing process or an alumite process in which a black body absorbing film (plastic, rubber, etc.) having a radiation rate of 0.94 or more is applied to the inner wall surface of a cylindrical holder that is a guide cylinder. A method of forming a black body absorbing film by the above is proposed (for example, refer to paragraph 0017 and paragraph 0018 of FIG. 3, FIG. 3 etc.).

  However, when black body processing is performed on the inner wall of the guide tube in this manner, a plurality of problems are inevitably caused. That is, firstly, the guide tube having the black body absorbing film formed on the inner wall by the black body treatment absorbs the infrared rays incident thereon and the temperature easily rises. The temperature of the inner wall rises, and the inner wall surface is blackbody treated, so the emissivity is high. Therefore, infrared radiation from the inner wall increases, and a part of the radiation is incident on an infrared absorbing film provided with a thermal element for detecting infrared rays to promote the temperature rise. Originally, the heat source should be only the object to be detected, but by applying black body processing, the inner wall of the guide cylinder acts as the second heat source, and the temperature of the object to be detected is also the temperature of the inner wall of the guide cylinder As a result, the sensitivity error of the non-contact temperature sensor is caused. In other words, even if infrared rays are once absorbed by the black body absorbing film, the thermal energy is emitted again by the black body radiation (secondary radiation), so that the effect of preventing infrared reflection on the inner wall of the guide tube may not make sense. There is.

  Second, the temperature change of the inner wall of the guide cylinder is affected by the heat capacity of the guide cylinder, and therefore a delay occurs compared to the temperature change of the detection target. For example, even if the temperature of the detection target suddenly rises, the inner wall of the guide tube receives the radiant heat and the temperature starts to rise. As a result, the secondary radiation radiated from the inner wall of the guide tube is also detected. It will begin to increase with a delay from the temperature rise. Conversely, even if the temperature of the object to be detected drops sharply and the amount of infrared rays received by the inner wall of the guide tube decreases sharply, the temperature of the inner wall of the guide tube decreases slowly. The emitted secondary radiation will also decrease slowly. That is, it is difficult to instantaneously detect the temperature change of the detection target, and a delay occurs in the temperature detection responsiveness.

  Third, as described above, when the temperature of the infrared absorbing film rises due to infrared radiation from the black body absorbing film, the heat is transferred to the entire non-contact temperature sensor, thereby increasing the ambient temperature. Further, since the heat due to the temperature rise of the guide tube itself is also conducted to the entire non-contact temperature sensor, the ambient temperature further rises. In this case, the temperature of the infrared absorption film and the ambient temperature are close to each other, and the difference between the two becomes small. As a result, the sensitivity of the non-contact temperature sensor is significantly lowered.

  Fourthly, in order to perform black body treatment such as coating treatment, anodizing treatment, anodizing treatment, etc. as described in Patent Document 1, any of these steps are required, The manufacturing cost will increase. In particular, when the non-contact temperature sensor is small, it is extremely difficult to paint the inner wall surface of the small guide cylinder. For example, in order to apply only a necessary part of the inner wall of the guide tube, each small part must be accurately masked. In addition, when the heat source becomes high temperature, the black body absorbing film is exposed to high temperature, so in order to improve its durability, for example, baking coating or the like requires high temperature and long drying time, and production As a result, the manufacturing cost is further increased. Furthermore, a coating treatment using an organic solvent is not preferable in terms of working environment and natural environment, and anodizing treatment and alumite treatment are not preferable in terms of the natural environment from the viewpoint of waste liquid treatment.

  Therefore, the present invention has been made in view of such circumstances, and detects the temperature of the detection object instantaneously while suppressing sensitivity errors and sensitivity reduction, and increases man-hours and costs during production, and productivity. It is an object of the present invention to provide a non-contact temperature sensor that can prevent the deterioration of the working environment and the natural environment.

  In order to solve the above-described problems, a non-contact temperature sensor according to the present invention is a non-contact temperature sensor that measures the temperature of a heat source in a non-contact manner, and an infrared detection thermosensitive element that detects the amount of infrared radiation emitted from the heat source. A temperature-compensating thermosensitive element that detects the amount of heat from the external environment, and a guide cylinder that is provided so as to demarcate the temperature detection field of view by the infrared-sensitive thermosensitive element in the heat source. A light receiving device including an opening and a body including an inclined wall portion that extends from the opening toward a light receiving surface on which the infrared detecting thermal element is disposed, and is inclined with respect to a vertical direction of the light receiving surface, and includes the infrared detecting thermal element A light-shielding space formed by the body portion is provided around the range.

  The non-contact temperature sensor configured in this way is arranged so that the opening of the guide cylinder faces the heat source, and the radiant infrared rays from the heat source enter the inside (internal space) of the guide cylinder from the opening of the guide cylinder. . Among the radiant infrared rays thus guided to the guide tube, the thermal energy of the infrared rays that reach the light receiving range including the infrared detecting thermal element is appropriately applied to the infrared absorbing means (infrared absorbing film or the like). Then, based on the temperature rise of the infrared absorbing means detected by the infrared detecting thermal element and the ambient temperature detected by the temperature compensating thermal element, the amount of radiation infrared radiation and the temperature of the heat source are measured.

  At this time, a part of the radiant infrared rays incident on the inner side from the opening of the guide cylinder directly reach the light receiving range including the infrared detecting thermal element, and the remaining part proceeds toward the inner wall of the guide cylinder body. Alternatively, it can be reflected by the inner wall of the body portion of the guide tube, but at least a part, preferably all, of the radiated infrared rays can be reflected by a body portion including an inclined wall portion that extends obliquely with respect to the vertical direction of the light receiving surface. The light is directed to a light-shielding space formed around the light receiving range including the infrared detecting thermal element, and is prevented from reaching the light receiving range including the infrared detecting thermal element. Therefore, even if the black body treatment is not applied to the inner wall of the guide tube as in the prior art, the sensitivity error of the non-contact temperature sensor due to the infrared component reflected by the inner wall of the guide tube, the decrease in sensitivity, and its secular variation are prevented. The

  In addition, as described above, at least a part, preferably all, of the radiated infrared rays from the heat source is received by the body including the inclined wall portion that is inclined with respect to the vertical direction of the light receiving surface and includes the infrared detecting thermal element. Directed to a light-shielding space formed around the area. In other words, since the radiant infrared rays from the heat source are reflected on the inner wall of the barrel portion of the guide tube and are indirectly prevented from reaching the infrared absorption film, the responsiveness to the temperature change of the heat source as the detection object is improved. Only the temperature change of the heat source that is the detection object can be instantaneously detected.

  In addition, since the black body treatment is not applied to the inner wall of the body of the guide tube, the non-contact temperature sensor detects the heat due to the temperature rise caused by infrared radiation from the black body absorbing film and the heat due to the temperature rise of the guide tube itself. Since it is not conducted to the whole and the difference between the temperature of the infrared absorption film and the ambient temperature is suppressed, the sensitivity of the non-contact temperature sensor can be prevented from being lowered.

  Further, since the black body treatment of the guide tube is unnecessary, it is possible to sufficiently prevent the increase in man-hours and costs during production, the decrease in productivity, and the deterioration of the work environment and the natural environment.

  The trunk portion preferably has a lid portion that extends from the opening side end portion of the inclined wall portion toward the inside of the guide tube. In this case, since the light shielding space formed by the body portion is secured in a wider range, the radiated infrared rays from the heat source are reflected by the inner wall of the body portion of the guide tube and indirectly to the light receiving range including the heat sensing element for detecting infrared rays. It can be further prevented from reaching.

When the guide tube is viewed in cross section, the angle between the inclined wall portion and the light receiving surface is δ, and the angle between the perpendicular to the light receiving surface and the straight line connecting the center of the light receiving range and the opening side end of the inclined wall portion is α. Then, it is preferable that δ and α satisfy the following relational expression (1).
0 ° <δ ≦ 45 ° + α / 2 Formula (1)
In this case, the radiated infrared rays from the heat source are reflected by the inner wall of the trunk portion of the guide tube and are prevented from reaching the center of the light receiving range including the infrared detecting thermal element, that is, the region where the infrared detecting thermal element exists.

When the guide tube is viewed in cross-section, the angle between the inclined wall portion and the light receiving surface is δ, and the angle between the perpendicular to the light receiving surface and the straight line connecting the peripheral edge of the light receiving range and the opening side end of the inclined wall portion is Assuming β, δ and β preferably satisfy the following relational expression (2).
0 ° <δ ≦ 45 ° + β / 2 Formula (2)
In this case, the radiant infrared rays from the heat source are reflected by the inner wall of the body portion of the guide tube and are prevented from indirectly reaching the entire region of the light receiving range including the infrared detecting thermal element. That is, the radiant infrared ray reflected by the inner wall of the body portion of the guide tube cannot reach any region of the light receiving range.

  The trunk portion preferably has a straight wall portion that hangs down from the light receiving surface side end portion of the inclined wall portion. In this case, since the expansion of the body portion is suppressed, the non-contact temperature sensor can be reduced in size.

  According to the non-contact temperature sensor of the present invention, the temperature of the detection object is instantaneously detected while suppressing the sensitivity error and the decrease in sensitivity, and the man-hour and cost at the time of manufacture, the decrease in productivity, and Deterioration of work environment and natural environment can be prevented.

It is a top view which shows the structure of the non-contact temperature sensor which concerns on 1st Embodiment of this invention. It is a model cutting part end view of the non-contact temperature sensor in alignment with the II line in FIG. 1, and is a figure which shows a non-contact temperature sensor with the heat source which is a detection target. It is a model cutting part end elevation for explaining a light guide path of a non-contact temperature sensor concerning a 1st embodiment of the present invention. It is a model cutting part end view for demonstrating the preferable inclination angle of the inclination wall part of the guide cylinder of the non-contact temperature sensor which concerns on 1st Embodiment of this invention. It is a model cutting part end view for demonstrating the more preferable inclination angle of the inclination wall part of the guide cylinder of the non-contact temperature sensor which concerns on 1st Embodiment of this invention. It is a top view which shows the structure of the non-contact temperature sensor which concerns on 2nd Embodiment of this invention. It is a model cutting part end view of the non-contact temperature sensor along the II-II line in FIG. It is a model cutting part end elevation for demonstrating the preferable inclination angle of the inclination wall part of the guide cylinder of the non-contact temperature sensor which concerns on 2nd Embodiment of this invention. It is a model cutting part end elevation for demonstrating the more preferable inclination angle of the inclination wall part of the guide cylinder of the non-contact temperature sensor which concerns on 2nd Embodiment of this invention. It is a top view which shows the structure of the non-contact temperature sensor which concerns on 3rd Embodiment of this invention. It is a model cutting part end view of the non-contact temperature sensor which follows the III-III line in FIG. It is a model cutting part end elevation for demonstrating the preferable inclination angle of the inclination wall part of the guide cylinder of the non-contact temperature sensor which concerns on 3rd Embodiment of this invention. It is a model cutting part end elevation for demonstrating the more preferable inclination angle of the inclination wall part of the guide cylinder of the non-contact temperature sensor which concerns on 3rd Embodiment of this invention. It is a model cutting part end view for demonstrating the preferable connection position of the inclination wall part and straight wall part of the guide cylinder of the non-contact temperature sensor which concerns on 3rd Embodiment of this invention. It is a top view which shows the structure of the non-contact temperature sensor which concerns on 4th Embodiment of this invention. It is a model cutting part end view of the non-contact temperature sensor in alignment with the IV-IV line in FIG. It is a model cutting part end view for demonstrating the preferable inclination angle of the inclination wall part of the guide cylinder of the non-contact temperature sensor which concerns on 4th Embodiment of this invention. It is a model cutting part end view for demonstrating the more preferable inclination angle of the inclination wall part of the guide cylinder of the non-contact temperature sensor which concerns on 4th Embodiment of this invention. It is a model cutting part end view for demonstrating the preferable connection position of the inclination wall part and straight wall part of the guide cylinder of the non-contact temperature sensor which concerns on 4th Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail. In the description, the same reference numerals are used for the same elements or elements having the same function, and redundant description is omitted. Further, the positional relationship such as up, down, left and right is based on the positional relationship shown in the drawings unless otherwise specified. Further, the dimensional ratios in the drawings are not limited to the illustrated ratios. Furthermore, the following embodiment is an illustration for explaining the present invention, and is not intended to limit the present invention only to the embodiment. Furthermore, the present invention can be variously modified without departing from the gist thereof.

(First embodiment)
First, with reference to FIG.1 and FIG.2, the structure of 1st Embodiment of this invention is demonstrated. FIG. 1 is a top view showing a configuration of a non-contact temperature sensor 100 according to the first embodiment of the present invention. FIG. 2 is a schematic end view of the non-contact temperature sensor 100 taken along line II in FIG. 1, and shows the non-contact temperature sensor 100 together with a heat source 7A that is a detection target.

  The non-contact temperature sensor 100 has a structure in which a support plate 13 provided with an infrared absorption film M that absorbs radiated infrared rays and generates heat is sandwiched between a base 11 of the sensor body 10 and a cover housing 12. A bottomed recess 21 is formed in the base 11. In addition, an infrared detection thermal element 15 for detecting the amount of heat of radiated infrared light is fixed to the lower surface (back surface) of the infrared absorbing film M in the bottomed recess 21 in the figure. Thus, the infrared detecting thermal element 15 is installed in the space between the back surface of the infrared absorbing film M and the bottom surface of the bottomed recess 21.

  Furthermore, the bottomed recess 21 has a region covered with the support plate 13 and shielded from light. A temperature-compensating thermosensitive element 16 for detecting the ambient temperature is fixed to the lower surface (rear surface) of the infrared absorbing film M in the region covered with the support plate 13 and shielded from light. As described above, the temperature compensating thermosensitive element 16 is also installed in the space between the infrared absorbing film M and the bottom surface of the bottomed recess 21, similarly to the infrared detecting thermosensitive element 15.

  The material of the infrared ray absorbing film M is not particularly limited as long as it absorbs the infrared ray emitted from the heat source 7A and generates heat, and a material having an absorption peak for light having a wavelength of 4 μm to 10 μm called far infrared ray is used. Desirably, examples thereof include polyester, polyimide, polyethylene, polycarbonate, PPS (polyphenylene sulfide) resin, fluorine resin, silicone resin, and the like. Further, the infrared detecting heat sensitive element 15 and the temperature compensating heat sensitive element 16 are not particularly limited as long as the electric characteristics change according to the amount of heat received, and thermistor, thermopile, metal thermometer having resistance temperature characteristics. A body etc. can be illustrated preferably. Furthermore, the material of the sensor body 10 is preferably a material having a high thermal conductivity and a small heat capacity, for example, aluminum.

  A guide tube 30 having a rectangular tube-shaped body portion 31 in which an opening P is formed is provided at a portion of the cover body 12 of the sensor body 10 that faces the bottomed recess 21, and faces the bottomed recess 21. The infrared absorption film M arranged at the position where the heat absorption is shown is exposed at the bottom of the guide tube 30 to the external environment Z where the heat source 7A exists. The bottom of the guide tube 30 is a light receiving surface N on which the infrared detecting heat-sensitive element 15 is disposed, and a region of the light receiving surface N where the infrared absorbing film M is exposed to the external environment Z is an infrared detecting element that absorbs radiated infrared rays. The light receiving range Q including the thermal element 15 is obtained. In the present embodiment, the size of the light receiving range Q is set smaller than the size of the opening P. Here, the size of the opening P defines the angular range of the radiated infrared rays incident on the light receiving range Q.

  The body portion 31 of the guide tube 30 is formed of a short-side inclined wall portions 31a and 31b and long-side inclined wall portions 31c and 31d extending from the opening P toward the light-receiving surface N while being inclined with respect to the vertical direction of the light-receiving surface N. It is comprised from four inclination wall parts 31a-31d. In other words, each inclined wall part 31a-31d has the inclination which inclines inside the guide cylinder 30 (internal space side), and the front-end | tip is the opening P of the guide cylinder 30 in which the radiation infrared rays from the external environment Z inject. It extends toward the front, that is, obliquely upward in the figure. The short-side inclined wall portions 31a and 31b have a substantially trapezoidal shape, and face each other in the longitudinal direction of the guide tube 30 when the non-contact temperature sensor 100 is viewed from above in the figure. The long-side inclined wall portions 31c and 31d have a substantially trapezoidal shape, and face each other in the short direction of the guide tube 30 when the non-contact temperature sensor 100 is viewed from above in the figure. The side edges of the short side inclined wall portions 31a and 31b and the long side inclined wall portions 31c and 31d are connected to each other to form one rectangular tube-shaped body portion 31. Moreover, each inclination wall part 31a-31d has the opening side edge part AD, and the light-receiving surface side edge part IL. Here, the inclination of each inclined wall part 31a-31d is bent and formed inside the guide cylinder 30 (internal space side) by a simple press work or the like. In addition, in this embodiment, although the trunk | drum 31 of the guide cylinder 30 is exhibiting the square cylinder shape, you may exhibit the cylindrical shape.

  The guide tube 30 has a light shielding space W on the inner side (inside space side) and around the light receiving range Q. The light shielding space W is a space (a region surrounded by a dotted line in the figure) formed by the body portion 31 of the guide tube 30, and specifically, is disposed at the inclined wall portions 31 a to 31 d and the bottom portion of the guide tube 30. It is a space surrounded by a virtual straight line connecting the support plate 13, the opening side end portions A to D of the inclined wall portions 31 a to 31 d and the support plate 13.

  Here, the operation of the light shielding space W will be described in detail. In the light shielding space W, components that have not reached the light receiving range Q among the radiant infrared rays incident from the opening P of the guide tube 30 gather. In other words, the components gathered in the light shielding space W do not affect the temperature detection of the non-contact temperature sensor 100. That is, the light-shielding space W in the present embodiment mainly includes components of the infrared rays radiated from the heat source 7A that are reflected by the body 31 of the guide tube 30 and indirectly reach the light-receiving surface N. It is a space to function so as not to reach.

  The heat source 7A is, for example, a heat fixing roller of a copying machine, and infrared components are radiated from the surface to the outside in all directions (all sky directions). The temperature detection visual field range Y in the heat source 7A is geometric from the light receiving range Q of the infrared absorption film M including the infrared detecting thermal element 15 and the tip position of the long side end that defines the opening range of the opening P of the guide tube 30. Defined scientifically. That is, as shown in FIG. 2, the edges Qa and Qb of the light receiving range Q of the infrared absorbing film M and the edges of the openings P far from the edges (openings of the short-side inclined wall portions 31a and 31b). The positions where imaginary lines (two-dot chain lines in the drawing, angle of view ω) respectively connecting the side ends A and B pass through the heat source 7A correspond to the edges Ya and Yb of the temperature detection visual field range Y. Thus, the guide tube 30 has a function of limiting the direction and angle of the radiant infrared detection.

  As described above, in the non-contact temperature sensor 100 according to the present embodiment, the radiant infrared rays from the heat source 7A, which is a detection target existing in the external environment Z, are emitted from the opening P of the guide tube 30 that functions as a light guide. The light enters the inside of the body portion 31 (the internal space of the guide tube 30). The radiant infrared rays that have reached the light receiving range Q of the infrared absorbing film M heat the infrared absorbing film M, the amount of heat detected by the infrared detecting thermal element 15, and the value and the temperature compensating thermal element 16 detected. Based on the value of the amount of heat, the temperature of the heat source 7A is measured.

  At this time, a part of the radiant infrared ray that has entered the opening P of the guide tube 30 directly reaches the light receiving range Q including the infrared detecting thermal element 15, and the remaining part is the trunk of the guide tube 30. 31 may proceed toward the inner wall of 31 or may be reflected by the inner wall of the trunk portion 31 of the guide tube 30, but at least a part, preferably all of the radiated infrared rays is inclined with respect to the vertical direction of the light receiving surface N. The body portion 31 including the inclined wall portions 31 a to 31 d extending in the direction is directed to the light shielding space W formed around the light receiving range Q including the infrared detecting thermal element 15, and includes the infrared detecting thermal element 15. Reaching the range Q is prevented. Therefore, the sensitivity error of the non-contact temperature sensor 100 caused by the infrared component reflected by the inner wall of the trunk portion 31 of the guide cylinder 30 without performing black body processing on the inner wall or the like of the trunk portion 31 of the guide cylinder 30 as in the prior art. It is possible to prevent a decrease in sensitivity and its aging.

  In addition, as described above, the non-contact temperature sensor 100 according to the present embodiment has an inclined wall portion in which at least a part, preferably all of the radiated infrared rays from the heat source 7A extend with an inclination with respect to the vertical direction of the light receiving surface N. The body part 31 including 31a to 31d is directed to the light shielding space W formed around the light receiving range Q including the infrared detecting thermal element 15. That is, since the radiant infrared rays from the heat source 7A are reflected by the inner wall of the body portion 31 of the guide tube 30 and indirectly reach the infrared absorption film M, the temperature change of the heat source 7A that is the detection target is suppressed. Responsiveness is improved, and only a temperature change of the heat source 7A, which is a detection target, can be detected instantaneously.

  Further, since the non-contact temperature sensor 100 according to the present embodiment does not perform black body processing on the inner wall or the like of the trunk portion 31 of the guide cylinder 30, heat or heat due to temperature rise caused by infrared radiation from the black body absorbing film Heat due to the temperature rise of the guide cylinder 30 itself is not conducted to the entire non-contact temperature sensor 100, and the difference between the temperature of the infrared absorption film M and the ambient temperature is suppressed, so that the non-contact temperature sensor 100 The decrease in sensitivity can be prevented.

  Furthermore, since the non-contact temperature sensor 100 according to the present embodiment does not require the black body treatment of the guide cylinder 30, the man-hour and cost at the time of manufacture, the productivity is lowered, and the working environment and the natural environment are reduced. Deterioration can be sufficiently prevented.

  Here, with reference to FIG. 3, the light guide path | route of the infrared rays from the heat source 7A with respect to the non-contact temperature sensor 100 which concerns on this embodiment is demonstrated in detail. FIG. 3 is a schematic end view of the cut portion for explaining the light guide path of the non-contact temperature sensor 100 according to the first embodiment of the present invention.

  As shown in FIG. 3, as an example of radiant infrared rays incident from the opening P, an infrared component 1000 that directly reaches the light receiving range Q and an infrared component 1001 that reaches the inner wall surface of the inclined wall portion 31 a of the guide tube 30. Then, since the infrared component 1000 directly reaches the light receiving range Q, the infrared component 1000 reaches the light receiving range Q without being affected by the state of the inner wall surface of the inclined wall portion 31a of the guide tube 30. On the other hand, the infrared component 1001 reaches the light shielding space W formed by the inclined wall portion 31a (body portion 31) of the guide tube 30 and is reflected by the inner wall surface of the inclined wall portion 31a of the guide tube 30. The reflected light is affected by the state of the inner wall surface of the inclined wall portion 31a of the guide tube 30. However, since the inclined wall portion 31a of the guide tube 30 is inclined with respect to the vertical direction of the light receiving surface N, the reflected light is directed into the light shielding space W and reaches the arrival point V around the light receiving range Q. To reach. Therefore, since it is not influenced by the inclined wall part 31a (body part 31) of the guide cylinder 30, the sensitivity error of the non-contact temperature sensor 100 can be prevented. If the inclined wall portion 31a of the guide tube 30 is regarded as a straight wall extending perpendicularly to the light receiving surface N, the opening side end A of the inclined wall portion 31a of the guide tube 30 is directed to the light receiving surface N. If the end portion extending vertically is the light receiving surface side end portion I ′, a virtual straight line AI ′ connecting the opening side end portion A of the inclined wall portion 31 a and the light receiving surface side end portion I ′ is formed in the body portion 31 of the guide tube 30. It will be equivalent. In this case, the infrared component 1001 is reflected on the surface of the virtual straight line AI ′ and reaches the arrival point V ′ located within the light receiving range Q. Therefore, the non-contact temperature sensor 100 is likely to cause a sensitivity error due to the influence of the body portion 31 of the guide tube 30.

  Next, with reference to FIG. 4, a preferable inclination angle of the angle δ formed by the inclined wall portions 31a to 31d of the guide tube 30 of the non-contact temperature sensor 100 according to the present embodiment and the light receiving surface N will be described in detail. FIG. 4 is a schematic cut-part end view for explaining preferred inclination angles of the inclined wall portions 31a to 31d of the guide tube 30 of the non-contact temperature sensor 100 according to the first embodiment of the present invention.

  As shown in FIG. 4, the inclined wall portion 31 a of the guide cylinder 30 has an inclination of an angle δ with respect to the light receiving surface N. Similarly, the inclined wall portion 31 b of the guide tube 30 has an angle δ with respect to the light receiving surface N. Here, if the inner walls of the inclined wall portions 31a and 31b of the guide tube 30 are reflection surfaces, the mirror image of the opening-side end portion A of the inclined wall portion 31a of the guide tube 30 has an extension line of the inclined wall portion 31b as an axis of symmetry. , A mirror image point A ′ at a line-symmetrical position. Similarly, when the inner walls of the inclined wall portions 31a and 31b of the guide tube 30 are reflection surfaces, the mirror image of the opening side end portion B of the inclined wall portion 31b of the guide tube 30 has an extension line of the inclined wall portion 31a as an axis of symmetry. , A mirror image point B ′ located in a line-symmetric position.

  By the way, among the radiant infrared rays from the heat source 7A, the range of the infrared component that directly reaches the center O of the light receiving range Q is the normal to the light receiving surface N and the opening O of the inclined wall portion 31a from the center O of the light receiving range Q. An angle 2α obtained by combining an angle α formed with a tentative straight line connecting the part A and an angle α formed between a perpendicular to the light receiving surface N and a virtual straight line connecting the center O of the light receiving range Q to the opening end B of the inclined wall portion 31b. It becomes the range.

  On the other hand, of the radiant infrared rays from the heat source 7A, the range of the infrared component reflected by the inclined wall portions 31a and 31b of the guide tube 30 and indirectly reaching the center O of the light receiving range Q is from the center O of the light receiving range Q. An angle θ1 formed by a virtual straight line connecting the opening side end B of the inclined wall portion 31b and a virtual straight line connecting the mirror image point A ′ from the center O of the light receiving range Q, and the opening of the inclined wall portion 31a from the center O of the light receiving range Q. The range is an angle θ2 formed by a virtual straight line connecting the side end A and a virtual straight line connecting the mirror image point B ′ from the center O of the light receiving range Q. For example, there are infrared components 2000 and 2001 that are reflected by the inner wall of the inclined wall portion 31a and reach the center O of the light receiving range Q.

In order to eliminate the infrared component reflected by the inclined wall portions 31a and 31b of the guide cylinder 30 and indirectly reaching the center O of the light receiving range Q, the angles θ1 and θ2 need to be 0 °. . These angles θ1 and θ2 change in conjunction with the inclination angle δ. When the inclination angle δ is reduced, the angles θ1 and θ2 are also reduced, and the inclination angle δ and the angle α are expressed by the following relational expression ( When 3) is satisfied, the angle θ1 and the angle θ2 are 0 °.
δ = 45 ° + α / 2 Formula (3)
That is, when the above relational expression (3) is satisfied, among infrared rays emitted from the heat source 7A, an infrared component that is reflected by the inclined wall portions 31a and 31b of the guide tube 30 and indirectly reaches the center O of the light receiving range Q is obtained. Disappear. At this time, a virtual straight line connecting the opening side end B of the inclined wall portion 31b and the mirror image point A ′ overlaps with a virtual straight line connecting the center O of the light receiving range Q to the opening side end B of the inclined wall portion 31b. A virtual straight line connecting the opening side end A of the inclined wall portion 31a and the mirror image point B ′ overlaps with a virtual straight line connecting the center O of Q to the opening side end A of the inclined wall portion 31a. In other words, an imaginary straight line connecting the opening side end B of the inclined wall portion 31b and the opening side end A of the inclined wall portion 31a and a imaginary straight line connecting the opening side end B of the inclined wall portion 31b and the mirror image point A ′. An inclined wall portion 31b overlaps a line segment (not shown) that bisects the angle formed, and an imaginary straight line connecting the opening-side end portion B of the inclined wall portion 31b and the opening-side end portion A of the inclined wall portion 31a and the inclined wall portion. The inclined wall portion 31a overlaps the line segment 101 that bisects the angle formed by the opening-side end A of 31a and the virtual straight line connecting the mirror image point B ′.

Further, when the inclination angle δ is further reduced, the range in which the infrared component reflected by the inclined wall portions 31a and 31b of the guide cylinder 30 cannot reach indirectly is centered on the center O of the light receiving range Q. Spread toward the outside of Q. Therefore, it is preferable that the inclination angle δ and the angle α satisfy the following relational expression (4).
δ ≦ 45 ° + α / 2 Formula (4)

As can be seen from the above description, in the non-contact temperature sensor 100 according to the present embodiment, when the following relational expression (1) is satisfied, the infrared component reflected by the inclined wall portions 31a and 31b of the guide tube 30 is: Indirectly reaching the center O of the light receiving range Q can be prevented.
0 ° <δ ≦ 45 ° + α / 2 Formula (1)
Accordingly, the infrared component that reaches the center O of the light receiving range Q is only the component that directly reaches the center O of the light receiving range Q among the radiated infrared rays from the heat source 7A. That is, the infrared component reflected by the inclined wall portions 31a and 31b of the guide tube 30 is indirectly in the center O that most affects the sensitivity of the non-contact temperature sensor 100 in the light receiving range Q constituted by the infrared absorption film M. Can't be reached. As a result, the influence of the body portion 31 of the guide tube 30 on the temperature detection of the non-contact temperature sensor 100 is suppressed, so that a sensitivity error of the non-contact temperature sensor 100 can be prevented.

  Subsequently, with reference to FIG. 5, a more preferable inclination angle of the angle δ formed by the inclined wall portions 31 a to 31 d of the guide tube 30 of the non-contact temperature sensor 100 according to the present embodiment and the light receiving surface N will be described in detail. . FIG. 5 is a schematic cut end face view for explaining more preferable inclination angles of the inclined wall portions 31a to 31d of the guide tube 30 of the non-contact temperature sensor 100 according to the first embodiment of the present invention.

  As shown in FIG. 5, the inclined wall portion 31 a of the guide cylinder 30 has an inclination of an angle δ with respect to the light receiving surface N. Similarly, the inclined wall portion 31 b of the guide tube 30 has an angle δ with respect to the light receiving surface N. Here, if the inner walls of the inclined wall portions 31a and 31b of the guide tube 30 are reflection surfaces, the mirror image of the opening-side end portion A of the inclined wall portion 31a of the guide tube 30 has an extension line of the inclined wall portion 31b as an axis of symmetry. , A mirror image point A ′ at a line-symmetrical position. Similarly, when the inner walls of the inclined wall portions 31a and 31b of the guide tube 30 are reflection surfaces, the mirror image of the opening side end portion B of the inclined wall portion 31b of the guide tube 30 has an extension line of the inclined wall portion 31a as an axis of symmetry. , A mirror image point B ′ located in a line-symmetric position.

  By the way, among the radiant infrared rays from the heat source 7A, the range of the infrared component that directly reaches the light receiving range Q is the perpendicular to the light receiving surface N and the edge Qa of the light receiving range Q to the opening side end A of the inclined wall portion 31a. And an angle β formed by combining an angle β formed with a virtual straight line connecting the vertical line with respect to the light receiving surface N and a virtual straight line connecting the edge Qb of the light receiving range Q with the opening end B of the inclined wall portion 31b. It becomes a range.

  On the other hand, of the radiant infrared rays from the heat source 7A, the range of the infrared component reflected by the inclined wall portions 31a and 31b of the guide tube 30 and indirectly reaching the light receiving range Q is the inclined wall from the edge Qb of the light receiving range Q. The angle θ3 formed by the virtual straight line connecting the opening side end B of the portion 31b and the virtual straight line connecting the mirror image point A ′ from the edge Qb of the light receiving range Q, and the opening of the inclined wall portion 31a from the edge Qa of the light receiving range Q The range is an angle θ4 formed by a virtual straight line connecting the side end A and a virtual straight line connecting the mirror image point B ′ from the edge Qa of the light receiving range Q.

In order to eliminate the infrared component that is reflected by the inclined wall portions 31a and 31b of the guide cylinder 30 and indirectly reaches the light receiving range Q, the angles θ3 and θ4 need to be 0 °. These angles θ3 and θ4 change in conjunction with the inclination angle δ. When the inclination angle δ is reduced, the angles θ3 and θ4 are also reduced, and the inclination angle δ and the angle β are expressed by the following relational expression ( When 5) is satisfied, the angle θ3 and the angle θ4 are 0 °.
δ = 45 ° + β / 2 Formula (5)
That is, when the relational expression (5) is satisfied, the infrared component reflected from the inclined wall portions 31a and 31b of the guide tube 30 and indirectly reaching the light receiving range Q is eliminated from the radiated infrared rays from the heat source 7A. At this time, a virtual straight line connecting the opening side end B of the inclined wall part 31b and the mirror image point A ′ overlaps with a virtual straight line connecting the edge Qb of the light receiving range Q to the opening side end B of the inclined wall part 31b. A virtual straight line connecting the opening side end A of the inclined wall portion 31a and the mirror image point B ′ overlaps with a virtual straight line connecting the edge Qa of the range Q to the opening side end A of the inclined wall portion 31a. In other words, an imaginary straight line connecting the opening side end B of the inclined wall portion 31b and the opening side end A of the inclined wall portion 31a and a imaginary straight line connecting the opening side end B of the inclined wall portion 31b and the mirror image point A ′. An inclined wall portion 31b overlaps a line segment (not shown) that bisects the angle formed, and an imaginary straight line connecting the opening-side end portion B of the inclined wall portion 31b and the opening-side end portion A of the inclined wall portion 31a and the inclined wall portion. The inclined wall 31a overlaps the line segment 111 that bisects the angle formed by the opening-side end A of 31a and the virtual straight line connecting the mirror image point B ′.

Further, when the inclination angle δ is further reduced, the infrared component reflected by the inclined wall portions 31a and 31b of the guide tube 30 can reach only outside the light receiving range Q. Therefore, it is preferable that the inclination angle δ and the angle β satisfy the following relational expression (6).
δ ≦ 45 ° + β / 2 Formula (6)

As can be seen from the above description, in the non-contact temperature sensor 100 according to the present embodiment, when the following relational expression (2) is satisfied, the infrared component reflected by the inclined wall portions 31a and 31b of the guide tube 30 is: Indirectly reaching the light receiving range Q can be prevented.
0 ° <δ ≦ 45 ° + β / 2 Formula (2)
Therefore, the infrared component that reaches the light receiving range Q is only the component that directly reaches the light receiving range Q among the radiated infrared rays from the heat source 7A. That is, the infrared component reflected by the inclined wall portions 31a and 31b of the guide cylinder 30 is in the entire light-receiving range Q constituted by the infrared absorption film M and affects the sensitivity of the non-contact temperature sensor 100. It is prevented from reaching indirectly. As a result, the temperature detection of the non-contact temperature sensor 100 is not affected by the body portion 31 of the guide tube 30, and a sensitivity error of the non-contact temperature sensor 100 can be prevented.

(Second Embodiment)
Next, the configuration of the second embodiment of the present invention will be described with reference to FIGS. FIG. 6 is a top view showing a configuration of a non-contact temperature sensor 200 according to the second embodiment of the present invention. FIG. 7 is a schematic end view of the non-contact temperature sensor 200 taken along line II-II in FIG. The non-contact temperature sensor 200 according to the second embodiment is different from the non-contact temperature sensor 100 according to the first embodiment in that the body 131 of the guide tube 130 includes lid portions 131e to 131h. Hereinafter, a description will be given focusing on differences from the first embodiment.

  Similarly to the non-contact temperature sensor 100 of the first embodiment, the non-contact temperature sensor 200 has a rectangular tube shape in which an opening P is formed at a portion facing the bottomed recess 21 in the cover housing 12 of the sensor body 10. A guide tube 130 having a body 131 is provided.

  The body 131 of the guide tube 130 has inclined wall portions 131a to 131d. However, in this embodiment, the trunk | drum 131 is further provided with the cover parts 131e-131h, and this point is different from 1st Embodiment.

  The cover parts 131e-131h are extended toward the inner side (internal space side) of the guide cylinder 130 from the opening side edge part AD of inclined wall part 131a-131d, respectively. In the present embodiment, the lid portions 131e to 131h extend in a direction parallel to the extending direction of the light receiving surface N. A light shielding space W is formed around the light receiving range Q on the inner side (inside the inner space) of the guide tube 130 by the body 131 composed of the inclined walls 131a to 131d and the lids 131e to 131h. . Specifically, the inclined wall portions 131a to 131d, the lid portions 131e to 131h, the support plate 13 disposed at the bottom of the guide tube 130, the opening side end portions E to H of the lid portions 131e to 131h, and the support plate. 13 is a space surrounded by a virtual straight line connecting 13.

  As described above, in the non-contact temperature sensor 200 according to the present embodiment, the body portion 131 has the lid portion 131e extending from the opening side end portions A to D of the inclined wall portions 131a to 131d toward the inside of the guide tube 130. ~ 131h. For this reason, since the light-shielding space W formed by the body 131 is secured in a wider range, the radiant infrared rays from the heat source 7A are reflected by the inner wall of the body 131 of the guide tube 130 and include the infrared detecting thermal element 15. Indirectly reaching the light receiving range Q can be further prevented.

  In addition, since the non-contact temperature sensor 200 according to the present embodiment includes the lid portions 131e to 131h, even when the tip of the guide tube 130 is in contact with the heat source 7A that is a detection target, Due to the buffering effect of the lid portions 131e to 131h, the heat source 7A that is the detection target can be prevented from being damaged.

  Next, a preferable inclination angle of the angle δ formed by the inclined wall portions 131a to 131d of the guide tube 130 of the non-contact temperature sensor 200 according to the present embodiment and the light receiving surface N will be described in detail with reference to FIG. FIG. 8 is an end view of a schematic cut portion for explaining preferred inclination angles of the inclined wall portions 131a to 131d of the guide tube 130 of the non-contact temperature sensor 200 according to the second embodiment of the present invention.

As in the first embodiment, the non-contact temperature sensor 200 according to the present embodiment satisfies the following relational expression (1), and the infrared component reflected by the inclined wall portions 131a and 131b of the guide tube 130 receives light. Indirect access to the center O of the range Q can be prevented.
0 ° <δ ≦ 45 ° + α / 2 Formula (1)
Accordingly, the infrared component that reaches the center O of the light receiving range Q is only the component that directly reaches the center O of the light receiving range Q among the radiated infrared rays from the heat source 7A. That is, the infrared component reflected by the inclined wall portions 131a and 131b of the guide tube 130 is indirectly in the center O that most affects the sensitivity of the non-contact temperature sensor 200 in the light receiving range Q formed by the infrared absorption film M. Can't be reached. As a result, the influence of the body 131 of the guide tube 130 on the temperature detection of the non-contact temperature sensor 200 is suppressed, so that a sensitivity error of the non-contact temperature sensor 200 can be prevented.

  Subsequently, with reference to FIG. 9, a more preferable inclination angle of the angle δ formed by the inclined wall portions 131 a to 131 d of the guide tube 130 of the non-contact temperature sensor 200 according to the present embodiment and the light receiving surface N will be described in detail. . FIG. 9 is a schematic cut-part end view for explaining more preferable inclination angles of the inclined wall portions 131a to 131d of the guide tube 130 of the non-contact temperature sensor 200 according to the second embodiment of the present invention.

As in the first embodiment, the non-contact temperature sensor 200 according to the present embodiment satisfies the following relational expression (2), and the infrared component reflected by the inclined wall portions 131a and 131b of the guide tube 130 receives light. It is possible to prevent the range Q from being reached indirectly.
0 ° <δ ≦ 45 ° + β / 2 Formula (2)
Therefore, the infrared component that reaches the light receiving range Q is only the component that directly reaches the light receiving range Q among the radiated infrared rays from the heat source 7A. That is, the infrared component reflected by the inclined wall portions 131a and 131b of the guide tube 130 with respect to the entire region that affects the sensitivity of the non-contact temperature sensor 200 in the light receiving range Q constituted by the infrared absorbing film M. It is prevented from reaching indirectly. As a result, the temperature of the non-contact temperature sensor 200 is not affected by the body 131 of the guide tube 130, and a sensitivity error of the non-contact temperature sensor 200 can be prevented.

(Third embodiment)
Next, the configuration of the third embodiment of the present invention will be described with reference to FIGS. 10 and 11. FIG. 10 is a top view showing a configuration of a non-contact temperature sensor 300 according to the third embodiment of the present invention. FIG. 11 is a schematic end view of the non-contact temperature sensor 300 taken along line III-III in FIG. The non-contact temperature sensor 300 according to the third embodiment is different from the non-contact temperature sensor 100 according to the first embodiment in that the body portion 231 of the guide tube 230 has straight wall portions 231i to 231l. Hereinafter, a description will be given focusing on differences from the first embodiment.

  Similarly to the non-contact temperature sensor 100 of the first embodiment, the non-contact temperature sensor 300 has a rectangular tube shape in which an opening P is formed at a portion facing the bottomed recess 21 in the cover housing 12 of the sensor body 10. A guide tube 230 having a body portion 231 is provided.

  The trunk portion 231 of the guide tube 230 has inclined wall portions 231a to 231d. However, in this embodiment, the trunk | drum 231 is further provided with the straight wall parts 231i-231l, and this point is different from 1st Embodiment.

  The straight wall portions 231i to 231l are suspended from the light receiving surface side end portions I to L of the inclined wall portions 231a to 231d toward the light receiving surface N, respectively. In the present embodiment, the straight wall portions 231 i to 231 l extend in a direction parallel to the vertical direction of the light receiving surface N. A light shielding space W is formed around the light receiving range Q on the inner side (inside the inner space) of the guide tube 230 by the trunk portion 231 constituted by the inclined wall portions 231a to 231d and the straight wall portions 231i to 231l. Yes. Specifically, the inclined wall portions 231a to 231d, the straight wall portions 231i to 231l, the support plate 13 disposed at the bottom of the guide tube 230, and the opening side end portions A to D of the inclined wall portions 231a to 231d, It is a space surrounded by a virtual straight line connecting the support plates 13. In the present embodiment, the straight wall portions 231i to 231l extend in a direction parallel to the vertical direction of the light receiving surface N, but the inclination angle δ with respect to the vertical direction of the light receiving surface N of the inclined wall portions 231a to 231d. May be inclined with respect to the vertical direction of the light receiving surface N.

  As described above, in the non-contact temperature sensor 300 according to the present embodiment, the body portion 231 is a straight wall portion depending from the light receiving surface side end portions I to L of the inclined wall portions 231a to 231d toward the light receiving surface N. 231i to 231l. For this reason, the breadth of the trunk | drum 231 is suppressed and the non-contact temperature sensor 300 can be reduced in size.

  Next, with reference to FIG. 12, a preferable inclination angle of the angle δ formed by the inclined wall portions 231a to 231d of the guide tube 230 of the non-contact temperature sensor 300 according to this embodiment and the light receiving surface N will be described in detail. FIG. 12 is a schematic cut portion end view for explaining preferred inclination angles of the inclined wall portions 231a to 231d of the guide tube 230 of the non-contact temperature sensor 300 according to the third embodiment of the present invention.

Similarly to the first embodiment, the non-contact temperature sensor 300 according to the present embodiment satisfies the following relational expression (1), and the infrared component reflected by the inclined wall portions 231a and 231b of the guide tube 230 receives light. Indirect access to the center O of the range Q can be prevented.
0 ° <δ ≦ 45 ° + α / 2 Formula (1)
Accordingly, the infrared component that reaches the center O of the light receiving range Q is only the component that directly reaches the center O of the light receiving range Q among the radiated infrared rays from the heat source 7A. That is, the infrared component reflected by the inclined wall portions 231a and 231b of the guide tube 230 is indirectly in the center O that most affects the sensitivity of the non-contact temperature sensor 300 in the light receiving range Q formed of the infrared absorption film M. Can't be reached. As a result, the influence of the body 231 of the guide tube 230 on the temperature detection of the non-contact temperature sensor 300 is suppressed, so that a sensitivity error of the non-contact temperature sensor 300 can be prevented.

  Next, with reference to FIG. 13, a more preferable inclination angle of the angle δ formed by the inclined wall portions 231a to 231d of the guide tube 230 of the non-contact temperature sensor 300 according to the present embodiment and the light receiving surface N will be described in detail. . FIG. 13 is a schematic cut-part end view for explaining more preferable inclination angles of the inclined wall portions 231a to 231d of the guide tube 230 of the non-contact temperature sensor 300 according to the third embodiment of the present invention.

Similarly to the first embodiment, the non-contact temperature sensor 300 according to the present embodiment satisfies the following relational expression (2), and the infrared component reflected by the inclined wall portions 231a and 231b of the guide tube 230 receives light. It is possible to prevent the range Q from being reached indirectly.
0 ° <δ ≦ 45 ° + β / 2 Formula (2)
Therefore, the infrared component that reaches the light receiving range Q is only the component that directly reaches the light receiving range Q among the radiated infrared rays from the heat source 7A. That is, the infrared component reflected by the inclined wall portions 231a and 231b of the guide tube 230 with respect to the entire region that affects the sensitivity of the non-contact temperature sensor 300 in the light receiving range Q constituted by the infrared absorbing film M. It is prevented from reaching indirectly. As a result, the influence of the body 231 of the guide tube 230 on the temperature detection of the non-contact temperature sensor 300 is eliminated, and a sensitivity error of the non-contact temperature sensor 300 can be prevented.

  Here, with reference to FIG. 14, the preferable connection position of the inclined wall parts 231a-231d and the straight wall parts 231i-231l of the guide cylinder 230 is demonstrated in detail. FIG. 14 is a schematic cut portion end surface for explaining a preferable connection position between the inclined wall portions 231a to 231d and the straight wall portions 231i to 231l of the guide tube 230 of the non-contact temperature sensor 300 according to the third embodiment of the present invention. FIG.

First, a position where the inclined wall portion 231a and the straight wall portion 231i of the guide tube 230 are connected is defined as a connection point S, and a point where the light receiving surface N of the straight wall portion 231i intersects is defined as a light receiving surface side end portion T. Is defined as a point R, and an angle between a virtual straight line connecting the point R and the opening-side end A of the inclined wall portion 231a and a perpendicular to the light receiving surface N is defined as an angle γ. At this time, the inclination angle δ at which the infrared component reflected by the inclined wall portion 231a of the guide tube 230 does not reach the inner side of the point R of the light receiving range Q is expressed by the following equation (7).
δ = 45 ° + γ / 2 Formula (7)
That is, the infrared component that reaches the point R is incident from the opening side end B of the inclined wall portion 231b and becomes the uppermost portion (opening side end A) of the inclined wall portion 231a. If it is assumed that the body 231 of the guide tube 230 is composed only of the inclined wall 231a as in the first embodiment, the infrared component reflected at a position lower than the top of the inclined wall 231a is All of them reach outside the point R of the light receiving range Q. That is, the light reaches the outside of the point R of the light receiving range Q as it is reflected at a lower position of the inclined wall 231a. However, when the trunk portion 231 of the guide tube 230 includes the inclined wall portion 231a and the straight wall portion 231i as in the present embodiment, the straight wall is larger than the arrival point of the infrared component reflected by the inclined wall portion 231a. The arrival point of the infrared component reflected by the part 231i is located inside. At this time, the arrival point that reaches the light receiving surface N of the infrared component 3000 incident from the opening side end B of the inclined wall portion 231b and reflected by the uppermost portion (upward in the drawing) of the straight wall portion 231i coincides with the point R. When the connection point S is set as described above, the infrared component 3000 is reflected by the straight wall portion 231i at an angle deeper than that of the infrared component 3000, that is, an infrared component (not shown) that enters the portion other than the uppermost portion of the straight wall portion 231i. Since the light is reflected at a position (lower in the figure) lower than the position of the straight wall portion 231i, the light-receiving surface N that is located outside the point R is reached.

  Next, if the straight wall portion 231i is a mirror surface, the mirror image of the opening-side end portion B of the inclined wall portion 231b becomes a mirror image point B ″ at a line-symmetric position with the extension line of the straight wall portion 231i as the symmetry axis. The mirror image of the opening-side end A of the inclined wall portion 231a is a mirror image point A ″ at a line-symmetric position with the extension line of the straight wall portion 231i as the axis of symmetry. In addition, when the perpendicular line dropped from the opening-side end B of the inclined wall portion 231b to the light receiving surface N and the light receiving surface N intersect with each other, the intersection X is a mirror surface, and when the straight wall portion 231i is a mirror surface, the mirror image of the intersection X is a straight wall With the extended line of the portion 231i as the axis of symmetry, the mirror image point X ′ is located in a line-symmetric position. Furthermore, when the perpendicular line dropped from the opening side end A of the inclined wall portion 231a to the light receiving surface N and the light receiving surface N intersect with each other, and the straight wall portion 231i is a mirror surface, the mirror image of the intersection U is a straight wall With the extended line of the portion 231i as an axis of symmetry, it becomes a mirror image point U ′ at a line-symmetric position.

The distance between the opening-side end B of the inclined wall 231b and the opening-side end A of the inclined wall 231a is d, the opening-side end B of the inclined wall 231b and the opening-side end A of the inclined wall 231a. Is the height of h, the distance between the point R and the intersection U is r, and the x-axis with the intersection U as the origin is the xy orthogonal coordinate system along the extending direction of the light receiving surface N. , Y), the locus of the infrared component 3000 reaching the point R in this coordinate system can be obtained from the following equations (8) and (9). That is, the triangle RST that connects the point R, the connection point S, and the light receiving surface side end T of the straight wall portion 231i, and the triangle RB ″ X ′ that connects the point R, the mirror image point B ″, and the mirror image point X ′ are similar. Therefore, the relationship of the following formula (8) is satisfied.
(R + x) / y = (r + 2x + d) / h Formula (8)
The equation (9) obtained by solving the equation (8) is a locus to reach the point R of the infrared component 3000.
y = h × (r + x) / (r + 2x + d) Equation (9)
Therefore, it can be derived from the equation (9) that the locus reaching the point R of the infrared component 3000 is a part of a right-angled hyperbola with x = − (r + d) / 2 and y = h / 2 asymptotic lines. . Here, when the point where the inclined wall portion 231a extended by the inclination angle δ of Expression (7) and the right-angled hyperbola expressed by Expression (9) intersect is a connection point S, the infrared component is reflected on the inclined wall portion 231a. Thus, both of the component that reaches the light receiving surface N and the component that is reflected by the straight wall portion 231i and reaches the light receiving surface N reach outside the point R.

  As described above, the point that is reflected by the inclined wall portion 231a or the straight wall portion 231i of the infrared component 3000 and reaches the innermost side of the light receiving surface N is the point R. Therefore, the body of the guide tube 230 depends on the position of this point R. The range of the infrared component reflected by the unit 231 and reaching the light receiving range Q can be determined. That is, the point R is set outside the region of the light receiving range Q, and the point where the right-angled hyperbola obtained from the set point R and the inclined wall portion 231a intersect is set as a connection point S between the inclined wall portion 231a and the straight wall portion 231i. Thus, the infrared component reflected by the inclined wall portion 231a of the guide tube 230 is prevented from indirectly reaching the light receiving range Q, and the spread of the body portion 231 of the guide tube 230 is suppressed, so that the non-contact temperature sensor 300 is prevented. Can be miniaturized.

  Next, the specifics of the inclined wall portions 231a to 231d and the straight wall portions 231i to 231l of the guide tube 230 when the infrared component reflected on the body portion 231 of the guide tube 230 does not indirectly reach the center O of the light receiving range Q. A detailed connection position will be described in more detail.

In order to eliminate the infrared component reflected by the barrel 231 of the guide tube 230 and indirectly reaching the center O of the light receiving range Q, the infrared component is reflected by the barrel 231 of the infrared component and reaches the innermost side of the light receiving surface N. It is obtained by matching the point R with the center O of the light receiving range Q. That is, since the distance r is d / 2, the locus of the right-angled hyperbola expressed by the equation (9) is the equation (10).
y = h × (x + d / 2) / (2x + 3d / 2) Formula (10)
Here, when the point where the inclined wall portion 231a extended by the inclination angle δ of the equation (1) and the right-angled hyperbola represented by the equation (10) intersect is a connecting point S, the inclined wall portion 231a and the straight wall portion of the infrared component. The light does not reach the center O of the light receiving range Q by being reflected by 231i. Accordingly, the infrared component reflected by the inclined wall portion 231a of the guide tube 230 is prevented from indirectly reaching the center O of the light receiving range Q, and the spread of the body portion 231 of the guide tube 230 is suppressed, thereby preventing contact. The size of the temperature sensor 300 can be reduced.

  Subsequently, the specific connection of the inclined wall portions 231a to 231d and the straight wall portions 231i to 231l of the guide tube 230 when the infrared component reflected on the body portion 231 of the guide tube 230 does not reach the light receiving range Q indirectly. The position will be described in more detail.

In order to eliminate the infrared component reflected by the body 231 of the guide tube 230 and indirectly reaching the light receiving range Q, a point R that is reflected by the body 231 of the infrared component and reaches the innermost side of the light receiving surface N is set. It is obtained by matching with the edges Qa and Qb of the light receiving range Q. That is, if the distance between the edge Qa of the light receiving range Q and the intersection U is Qk, the distance r is Qk, and therefore the locus of the right-angled hyperbola expressed by the equation (9) is the equation (11).
y = h × (x + Qk) / (2x + Qk + d) Equation (11)
Here, assuming that the width of the light receiving range Q is Qf, the distance Qk is (d−Qf) / 2, and therefore, the locus of the right-angled hyperbola represented by Expression (11) is Expression (12).
y = h × (x + (d−Qf) / 2) / (2x + (3d−Qf) / 2) Equation (12)
Here, when the point where the inclined wall portion 231a extended by the inclination angle δ of the equation (2) and the right-angled hyperbola expressed by the equation (12) intersect is defined as the connection point S, the infrared light component is reflected by the inclined wall portions 231a and 231i. Thus, the light receiving range Q is not indirectly reached. Therefore, the infrared component reflected by the inclined wall portion 231a of the guide tube 230 is prevented from reaching the light receiving range Q, and the spread of the body portion 231 of the guide tube 230 is suppressed, so that the non-contact temperature sensor 300 is reduced in size. Can be achieved.

(Fourth embodiment)
Next, the configuration of the fourth embodiment of the present invention will be described with reference to FIGS. FIG. 15 is a top view showing a configuration of a non-contact temperature sensor 400 according to the fourth embodiment of the present invention. FIG. 16 is a schematic end view of the non-contact temperature sensor 400 along the line IV-IV in FIG. The non-contact temperature sensor 400 according to the fourth embodiment is different from the non-contact temperature sensor 100 according to the first embodiment in that the body portion 331 of the guide tube 330 includes lid portions 331e to 331h and straight wall portions 331i to 331l. Is different. Hereinafter, a description will be given focusing on differences from the first embodiment.

  Similarly to the non-contact temperature sensor 100 of the first embodiment, the non-contact temperature sensor 400 has a rectangular tube shape in which an opening P is formed at a portion facing the bottomed recess 21 in the cover housing 12 of the sensor body 10. A guide tube 330 having a body portion 331 is provided.

  The body portion 331 of the guide tube 330 has inclined wall portions 331a to 331d. However, in this embodiment, the trunk | drum 331 is further provided with the cover parts 331e-331h and the straight wall parts 331i-331l, and this point is different from 1st Embodiment.

  The lid portions 331e to 331h extend from the opening side end portions A to D of the inclined wall portions 331a to 331d toward the inside (inside space side) of the guide tube 330, respectively. In the present embodiment, the lid portions 331e to 331h extend in a direction parallel to the extending direction of the light receiving surface N.

  The straight wall portions 331i to 331l hang down from the light receiving surface side end portions I to L of the inclined wall portions 331a to 331d toward the light receiving surface N, respectively. In the present embodiment, the straight wall portions 331 i to 331 l extend in a direction parallel to the vertical direction of the light receiving surface N.

  Light is shielded inside the guide tube 330 (on the inner space side) and around the light receiving range Q by the body portion 331 including the inclined wall portions 331a to 331d, the lid portions 331e to 331h, and the straight wall portions 331i to 331l. A space W is formed. Specifically, the inclined wall portions 331a to 331d, the lid portions 331e to 331h, the straight wall portions 331i to 331l, the support plate 13 disposed at the bottom of the guide tube 330, and the opening side of the lid portions 331e to 331h It is a space surrounded by a virtual straight line connecting the end portions E to H and the support plate 13. In the present embodiment, the straight wall portions 331i to 331l extend in a direction parallel to the vertical direction of the light receiving surface N, but the inclination angle δ with respect to the vertical direction of the light receiving surface N of the inclined wall portions 331a to 331d. May be inclined with respect to the vertical direction of the light receiving surface N.

  As described above, in the non-contact temperature sensor 400 according to the present embodiment, the body portion 331 has the lid portion 331e extending from the opening side end portions A to D of the inclined wall portions 331a to 331d toward the inside of the guide tube 330. ~ 331h. For this reason, since the light shielding space W formed by the trunk portion 331 is secured in a wider range, the radiant infrared rays from the heat source 7A are reflected by the inner wall of the trunk portion 331 of the guide tube 330 and include the infrared detecting thermal element 15. Indirectly reaching the light receiving range Q can be further prevented.

  Further, in the non-contact temperature sensor 400 according to the present embodiment, the body portion 331 is a straight wall portion 331i to 331l that hangs down from the light receiving surface side end portions I to L of the inclined wall portions 331a to 331d toward the light receiving surface N. have. For this reason, the breadth of the trunk | drum 331 is suppressed and the size reduction of the non-contact temperature sensor 400 can be achieved.

  Next, with reference to FIG. 17, a preferable inclination angle of the angle δ formed by the inclined wall portions 331a to 331d of the guide tube 330 of the non-contact temperature sensor 400 according to the present embodiment and the light receiving surface N will be described in detail. FIG. 17 is a schematic cut end face view for explaining preferred inclination angles of the inclined wall portions 331a to 331d of the guide tube 330 of the non-contact temperature sensor 400 according to the fourth embodiment of the present invention.

Similarly to the first embodiment, the non-contact temperature sensor 400 according to the present embodiment satisfies the following relational expression (1), and the infrared component reflected by the inclined wall portions 331a and 331b of the guide tube 330 receives light. Indirect access to the center O of the range Q can be prevented.
0 ° <δ ≦ 45 ° + α / 2 Formula (1)
Accordingly, the infrared component that reaches the center O of the light receiving range Q is only the component that directly reaches the center O of the light receiving range Q among the radiated infrared rays from the heat source 7A. That is, the infrared component reflected by the inclined wall portions 331a and 331b of the guide tube 330 is indirectly directed to the center O that most affects the sensitivity of the non-contact temperature sensor 400 in the light receiving range Q constituted by the infrared absorption film M. Can't be reached. As a result, the influence of the body 331 of the guide tube 330 on the temperature detection of the non-contact temperature sensor 400 is suppressed, so that a sensitivity error of the non-contact temperature sensor 400 can be prevented.

  Next, with reference to FIG. 18, a more preferable inclination angle of the angle δ formed by the inclined wall portions 331a to 331d of the guide tube 330 of the non-contact temperature sensor 400 according to the present embodiment and the light receiving surface N will be described in detail. . FIG. 18 is a schematic cut end face view for explaining more preferable inclination angles of the inclined wall portions 331a to 331d of the guide tube 330 of the non-contact temperature sensor 400 according to the fourth embodiment of the present invention.

Similarly to the first embodiment, the non-contact temperature sensor 400 according to the present embodiment satisfies the following relational expression (2), and the infrared component reflected by the inclined wall portions 331a and 331b of the guide tube 330 receives light. It is possible to prevent the range Q from being reached indirectly.
0 ° <δ ≦ 45 ° + β / 2 Formula (2)
Therefore, the infrared component that reaches the light receiving range Q is only the component that directly reaches the light receiving range Q among the radiated infrared rays from the heat source 7A. That is, the infrared component reflected by the inclined wall portions 331a and 331b of the guide tube 330 is all over the region that affects the sensitivity of the non-contact temperature sensor 400 in the light receiving range Q constituted by the infrared absorbing film M. It is prevented from reaching indirectly. As a result, the temperature detection of the non-contact temperature sensor 400 is not affected by the body 331 of the guide tube 330, and a sensitivity error of the non-contact temperature sensor 400 can be prevented.

  Here, with reference to FIG. 19, the preferable connection position of the inclined wall part 331a-331d and the straight wall part 331i-331l of the guide cylinder 330 is demonstrated in detail. FIG. 19 is a schematic cut portion end surface for explaining a preferable connection position between the inclined wall portions 331a to 331d and the straight wall portions 331i to 331l of the guide tube 330 of the non-contact temperature sensor 400 according to the fourth embodiment of the present invention. FIG.

First, a position where the inclined wall portion 331a and the straight wall portion 331i of the guide tube 330 are connected is a connection point S, a point where the light receiving surface N of the straight wall portion 331i intersects is a light receiving surface side end portion T, Is defined as a point R, and an angle between a virtual straight line connecting the point R and the opening side end A of the inclined wall portion 331a and a perpendicular to the light receiving surface N is defined as an angle γ. At this time, the inclination angle δ at which the infrared component reflected by the inclined wall portion 331a of the guide tube 330 does not reach the inside of the point R of the light receiving range Q is expressed by the following equation (7).
δ = 45 ° + γ / 2 Formula (7)
That is, the infrared component that reaches the point R is incident from the opening side end B of the inclined wall portion 331b and becomes the uppermost portion (opening side end A) of the inclined wall portion 331a. If it is assumed that the body portion 331 of the guide tube 330 is composed only of the inclined wall portion 331a as in the first embodiment, the infrared component reflected at a position lower than the uppermost portion of the inclined wall portion 331a is All of them reach outside the point R of the light receiving range Q. That is, the light reaches the outside of the point R of the light receiving range Q as it is reflected at a lower position of the inclined wall portion 331a. However, when the trunk portion 331 of the guide tube 330 is composed of the inclined wall portion 331a and the straight wall portion 331i as in this embodiment, the straight wall is larger than the arrival point of the infrared component reflected by the inclined wall portion 331a. The arrival point of the infrared component reflected by the part 331i is located inside. At this time, the arrival point that reaches the light receiving surface N of the infrared component 4000 that is incident from the opening-side end portion B of the inclined wall portion 331b and reflected by the uppermost portion (upward in the drawing) of the straight wall portion 331i coincides with the point R. When the connection point S is set as described above, an infrared component (not shown) incident at an angle deeper than the infrared component 4000, that is, an infrared component (not shown) that is incident on a portion other than the uppermost portion of the straight wall portion 331i is reflected by the straight wall portion 331i. Since the light is reflected at a position (lower in the figure) lower than the position of the straight wall portion 331i, the light receiving surface N that is located outside the point R is reached.

  Next, when the straight wall portion 331i is a mirror surface, the mirror image of the opening-side end portion F of the lid portion 331f is a mirror image point F ′ at a line-symmetric position with the extension line of the straight wall portion 331i as an axis of symmetry. The mirror image of the opening-side end portion E of the portion 331e is a mirror image point E ′ at a line-symmetric position with the extension line of the straight wall portion 331i as the symmetry axis. Further, when the perpendicular line drawn from the opening-side end F of the lid 331f to the light receiving surface N and the point where the light receiving surface N intersects is an intersection Xf, and the straight wall 331i is a mirror surface, the mirror image of the intersection Xf is a straight wall portion. With the extended line of 331i as the axis of symmetry, this is the mirror image point Xf ′ at the line-symmetric position. Furthermore, when the perpendicular line dropped from the opening-side end E of the lid 331e to the light receiving surface N and the point where the light receiving surface N intersects are the intersection Ue, and the straight wall 331i is a mirror surface, the mirror image of the intersection Ue is a straight wall With the extended line of 331i as the axis of symmetry, it becomes a mirror image point Ue 'at a line-symmetric position.

The distance between the opening side end B of the inclined wall portion 331b and the opening side end A of the inclined wall portion 331a is d, and the height of the opening side end F of the lid portion 331f and the opening side end portion E of the lid portion 331e is high. The distance between the point R and the intersection Ue is r, and the x axis with the intersection Ue as the origin is an xy orthogonal coordinate system along the extending direction of the light receiving surface N, and the coordinates of the connection point S are (x, y ), The locus of the infrared component 4000 reaching the point R in this coordinate system can be obtained from the following equations (8) and (9). That is, the triangle RST connecting the point R, the connection point S, and the light receiving surface side end T of the straight wall portion 331i and the triangle RXf′F ′ connecting the point R, the mirror image point Xf ′, and the mirror image point F ′ are similar. Therefore, the relationship of the following formula (8) is satisfied.
(R + x) / y = (r + 2x + d) / h Formula (8)
The equation (9) obtained by solving the equation (8) is a locus to reach the point R of the infrared component 4000.
y = h × (r + x) / (r + 2x + d) Equation (9)
Therefore, it can be derived from the equation (9) that the locus of reaching the point R of the infrared component 4000 is a part of a right-angled hyperbola with x = − (r + d) / 2 and y = h / 2 asymptotic lines. . Here, when the point where the inclined wall portion 331a extended by the inclination angle δ of the equation (7) and the right-angled hyperbola expressed by the equation (9) intersect is defined as the connection point S, the infrared component is reflected on the inclined wall portion 331a. Thus, both the component that reaches the light receiving surface N and the component that reaches the light receiving surface N after being reflected by the straight wall portion 331i reach outside the point R.

  As described above, the point that is reflected by the inclined wall portion 331a or the straight wall portion 331i of the infrared component and reaches the innermost side of the light receiving surface N is the point R. Therefore, the trunk portion of the guide tube 330 is determined by the position of this point R. The range of the infrared component reflected by 331 and reaching the light receiving range Q can be determined. That is, the point R is set outside the region of the light receiving range Q, and the point where the right-angled hyperbola obtained from the set point R and the inclined wall portion 331a intersect is set as a connection point S between the inclined wall portion 331a and the straight wall portion 331i. Accordingly, the infrared component reflected by the inclined wall portion 331a of the guide tube 330 is prevented from indirectly reaching the light receiving range Q, and the spread of the body portion 331 of the guide tube 330 is suppressed, so that the non-contact temperature sensor 400 is prevented. Can be miniaturized.

  The preferred embodiments of the present invention have been described above. However, the present invention is not necessarily limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention.

For example, the position of the connection point S can be solved algebraically and the coordinates of the connection point S can be obtained as numerical values. In the fourth embodiment of the present invention, when the length of the lid portions 331f and 331e is c, the extension line of the inclined wall portion 331a having the inclination angle δ is expressed by the following equation (13).
y = −x × tan δ + c × tan δ + h Equation (13)
When the equations (13) and (9) are combined to obtain the coordinates (x, y) of the connection point S, the coordinates x and the coordinates y become the following equations (14) and (15), respectively.
x = c / 2-4 (d + Qk) / 4 + (h / 2) × cotδ + (1/2) × √ [{c + (d + Qk) / 2} ² + h × (2c + 3d−Qk) × cotδ + h ² cot ² δ] Formula (14)
y = h / 2 + h / 2 × (Qk−d) / [c / 2 + (d + r) / 4 + h / 2 × √ {{c + (d + Qk) / 2} ² + h × (2c + 3d−Qk) × cotδ + h ² cot ² δ ]] Formula (15)
In addition, the point that is reflected by either the inclined wall portion 331a or the straight wall portion 331i of the guide tube 330 in the infrared component and reaches the light receiving surface N is reflected by the uppermost portion of the straight wall portion 331i and on the light receiving surface N. When located outside the reaching point R, the following equation (16) may be added to the equations (14) and (15).
cot γ = h / (r + c) Formula (16)

  It can be used widely and effectively for non-contact measurement of the temperature of various other heat sources, including objects to be detected such as a heat fixing roller of a copying machine.

  7A ... Heat source, 10 ... Sensor body, 11 ... Base, 12 ... Cover housing, 13 ... Support plate, 15 ... Thermal sensing element for infrared detection, 16 ... Thermal sensing element for temperature compensation, 21 ... Bottomed recess, 30, 130, 230, 330 ... guide cylinder, 31, 131, 231, 331 ... trunk, 31a-31d, 131a-131d, 231a-231d, 331a-331d ... inclined wall, 100, 200, 300, 400 ... non-contact temperature sensor 101, 111 ... bisecting line segment, 131e-131h, 331e-331h ... lid, 231i-231l, 331i-331l ... straight wall, 1000, 1001, 2000, 2001, 3000, 4000 ... infrared component, A to D: Opening end of inclined wall, A ′, A ″, B ′, B ″, E ′, F ′, U ′, Ue ′, X ′, Xf ′ ... Mirror image point, AI ′ ... virtual straight line E to H: opening side end of lid, I to L: light receiving surface side end of inclined wall, I ′: virtual light receiving surface side end of inclined wall, M: infrared absorbing film, N: light receiving surface , O ... center of light receiving range, P ... aperture, Q ... light receiving range, Qa, Qb ... edge of light receiving range, Qf ... width of light receiving range, Qk ... distance between edge of light receiving range and intersection, R ... light receiving Arbitrary point on range Q, S ... connection point, T ... light receiving surface side end of straight wall, U, Ue, X, Xf ... intersection, V ... arrival point, V '... virtual arrival point, W ... light shielding Space, Y ... temperature detection field of view, Ya, Yb ... edge of temperature detection field of view, Z ... external environment, α, β, γ, θ1 to θ4 ... angle, δ ... inclination angle, c ... of the lid Length, d: distance between the opening side end portions of the inclined wall portion, h: height of the opening side end portion of the inclined wall portion, r: distance between the reaching point and the intersection, x, y: coordinates of the connection point

Claims (5)

  A non-contact temperature sensor that measures the temperature of the heat source in a non-contact manner, a thermal sensor for detecting infrared radiation that detects the amount of infrared radiation emitted from the heat source, and a thermal sensor for temperature compensation that detects the amount of heat from the external environment, A guide tube provided so as to demarcate a visual field range of temperature detection by the infrared detection thermal element in the heat source, and the guide cylinder has an opening, and the infrared detection thermal element from the opening. A body portion including an inclined wall portion extending obliquely with respect to a light receiving surface to be disposed with respect to a vertical direction of the light receiving surface, and around the light receiving range including the infrared detecting thermal element by the body portion A non-contact temperature sensor having a light-shielding space formed.   The non-contact temperature sensor according to claim 1, wherein the body portion includes a lid portion that extends from an opening-side end portion of the inclined wall portion toward the inside of the guide tube. When the guide tube is viewed in cross-section, an angle formed by the inclined wall portion and the light receiving surface is δ, a perpendicular to the light receiving surface, and a straight line connecting the center of the light receiving range and the opening side end portion of the inclined wall portion. The non-contact temperature sensor according to claim 1, wherein δ and α satisfy the following relational expression (1), where α is an angle formed by:
0 ° <δ ≦ 45 ° + α / 2 Formula (1) When the guide tube is viewed in cross-section, the angle formed by the inclined wall portion and the light receiving surface is δ, the perpendicular to the light receiving surface is connected to the peripheral edge of the light receiving range and the opening side end of the inclined wall portion. 3. The non-contact temperature sensor according to claim 1, wherein δ and β satisfy the following relational expression (2), where β is an angle formed with a straight line.
0 ° <δ ≦ 45 ° + β / 2 Formula (2)   5. The non-contact temperature sensor according to claim 3, wherein the body portion includes a straight wall portion that hangs down from a light receiving surface side end portion of the inclined wall portion.

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