JP2011141216A - Non-contact temperature sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a non-contact temperature sensor that facilitates correcting a temperature detection error even after assembly, and keeps a constant detection angle of visibility. <P>SOLUTION: The non-contact temperature sensor includes a temperature-sensitive element 20a for infrared detection and a temperature-sensitive element 20b for temperature compensation. It also includes a top plate 34 for shielding infrared and a casing 14 provided with a light guide 40 for leading infrared inside. The temperature-sensitive elements 20a and 20b are respectively mounted to a flexible printed circuit board 12 to keep the temperature-sensitive elements 20a for infrared detection arranged in an opening region of the light guide 40 of the casing, and the temperature-sensitive element 20b for temperature compensation arranged at the position hidden from a shielding surface 34a. A temperature adjustment member 18 that is integrated with an infrared shield 18b is located slidable between the flexible printed circuit board 12 and the top plate 34 of the casing 14. The infrared shield 18b shields a certain optional area within the opening region of the light guide 40, so that it is possible to adjust the sensitivity of the temperature-sensitive element 20a for infrared detection. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a non-contact temperature sensor that detects temperature by detecting infrared rays, and particularly relates to a non-contact temperature sensor that includes a temperature sensing element for detecting infrared rays and a temperature sensing element for temperature compensation.

  A temperature sensor that measures the temperature of the object to be measured with a contact method generally wears the contact part, the heat capacity of the thermal element itself that contacts the object to be measured causes measurement errors, and the object to be measured rotates. However, there is a problem that it is difficult to attach the temperature sensor in the case where the temperature sensor is installed, and the demand for a non-contact type temperature sensor that is easy to use is increasing.

  Conventionally, as a method of detecting temperature without contact, infrared rays emitted from the object to be measured are absorbed by an infrared absorber and converted into energy, and the temperature rise of the infrared absorber itself is detected by a temperature sensing element, which is converted into an electrical signal. A conversion method is used. In recent years, a non-contact temperature sensor has been proposed in which a temperature sensing element for infrared detection and a temperature sensing element for temperature compensation are combined to improve the accuracy of temperature measurement.

  As this type of non-contact temperature sensor, for example, as disclosed in Patent Document 1, an infrared detection temperature sensing element and a temperature compensation temperature sensing element are individually adhered and fixed to two resin films. Is stretched over a frame having a predetermined thermal conductivity and accommodated inside the housing, and of the two temperature sensing elements, the infrared sensing temperature sensing element is a light guide (infrared ray) provided on the housing. There is an infrared detector arranged in the opening area of the incident window, and the temperature compensation temperature sensing element is arranged at a position where infrared rays are shielded by the shielding surface (shielding portion) of the housing.

  In addition, as disclosed in Patent Document 2, the infrared detecting temperature sensing element and the temperature compensating thermosensitive element are attached to the resin film, the resin film is accommodated inside the housing, and of the two temperature sensing elements, The infrared sensing temperature sensing element is disposed in the opening region of the light guide provided in the housing, the temperature compensating temperature sensing element is disposed in a shielded space surrounded by the housing wall, and As a means for adjusting the amount of infrared light incident from the light guide unit, there is an infrared temperature sensor provided with a shielding unit for adjusting the opening area of the light guide unit. And the structure whose shield part is a variable projection part like a screw which protrudes inward from the inner wall surface of a light guide part is illustrated.

JP 7-260579 A JP 2003-156284 A

  However, the infrared detector disclosed in Patent Document 1 has a problem that an error occurs in temperature detection due to variations in the outer dimensions of the casing, and the yield during sensor manufacture is poor. Since this casing is mass-produced by casting a metal material, it can be manufactured inexpensively and efficiently, but some variation occurs in the external dimensions. The influence of this variation is not negligible even if it is a relatively small variation within the same lot.For example, if the opening area of the light guide part of the housing and the opening height dimension vary, the amount of incident infrared rays It fluctuates and a large error occurs in the detected temperature. In addition to variations in the outer dimensions of the casing, variations in the outer dimensions of the temperature sensitive element, the thickness of the resin film, the cross-sectional area of the conductor pattern, and the like cause errors in the detected temperature. And since this infrared detector is not provided with a means for correcting an error, a product with a large error has to be discarded as a defective product.

  On the other hand, the infrared temperature sensor of Patent Document 2 can correct the detected temperature error as described above by adjusting the amount of protrusion of a variable protrusion such as a screw. However, when the protrusion amount of the variable protrusion is adjusted, the opening area changes, so the detection viewing angle capable of receiving infrared light changes, and the infrared detectable range varies depending on the product. For example, when a measurement object at a specific position radiates infrared rays, it can be detected if a product with a small protrusion of the variable protrusion is used, but cannot be detected if a product with a large protrusion of the variable protrusion is used. Such an instability in product performance is undesirable.

  The present invention has been made in view of the above-described background art, and provides a non-contact temperature sensor that can easily correct a temperature detection error even after assembly and can also maintain a constant detection viewing angle. With the goal.

  The present invention is a non-contact temperature sensor provided with a temperature sensing element for detecting infrared rays and a temperature sensing element for temperature compensation, wherein a top plate portion forming a shielding surface for shielding infrared rays and a part of the top plate portion are opened. And the infrared detecting temperature sensing element and the temperature compensating temperature sensing element are mounted on a conductor pattern on the back side, and the top side is the top plate part. A flexible circuit board accommodated in the housing, an infrared shielding part, and a holding part for holding the infrared shielding part, the flexible printed circuit board, the top plate part, and the light guide part, A sensitivity adjusting member provided so that the position relative to the infrared sensing temperature sensing element can be adjusted, and the infrared sensing temperature sensing element is disposed in an opening region of the light guide portion of the housing. The temperature compensating temperature sensing element is: The infrared shielding portion of the sensitivity adjusting member is arranged at a position hidden behind the shielding surface, and shields an arbitrary constant area portion within the opening region of the light guide portion of the housing, and the infrared detecting temperature sensing element. It is a non-contact temperature sensor provided so that the sensitivity of the infrared sensing temperature sensing element can be adjusted by adjusting the position of the infrared sensing temperature sensor.

  The infrared shielding unit shields infrared rays across the opening region of the light guide unit in a direction perpendicular to the moving direction.

  Further, the surface of the infrared shielding part is subjected to a mirror surface treatment for infrared reflection or a surface treatment with a coating agent for electromagnetic wave reflection in the infrared region.

  The sensitivity adjustment member is provided with a movable adjustment knob operable from the outside of the housing. In addition, spacer means is disposed between the flexible printed circuit board and the top plate portion of the casing facing each other, and the spacer means includes the flexible printed circuit board, the top plate portion, and the light guide portion. A space in which the sensitivity adjusting member can slide is secured.

  The non-contact temperature sensor according to the present invention can easily correct the sensitivity by adjusting the sensitivity adjustment member in the operation confirmation test after assembling each member in the production process. Can be adjusted within a certain range. Further, since the sensitivity of temperature detection is corrected while keeping the contour shape and opening area of the opening of the light guide portion constant, the viewing angle of detection can be kept constant.

  Moreover, the effect of the sensitivity correction | amendment by an infrared shielding part can be further heightened by giving the infrared rays reflection process to the infrared shielding part of a sensitivity adjustment member, and preventing that a sensitivity adjustment member absorbs infrared rays.

  Further, the structure of the non-contact temperature sensor according to the present invention does not increase the outer shape because only a thin sensitivity adjusting member is added to the structure of the conventional non-contact temperature sensor. In addition, a structure in which the sensitivity adjustment member is provided with a movable adjustment knob and protrudes to the outside of the housing can be easily realized without complicating the structure of the housing.

  Furthermore, by providing a spacer between the flexible printed circuit board and the top plate portion, it is possible to easily ensure an appropriate space for the sensitivity adjusting member to slide smoothly.

It is a partial section perspective view showing the non-contact temperature sensor which is one embodiment of this invention. It is a perspective view which shows a sensitivity adjustment member. It is a longitudinal cross-sectional view of the longitudinal direction of this embodiment. It is a top view explaining operation | movement of the sensitivity adjustment member of this embodiment. It is a circuit block diagram which shows the structure of the temperature detection system which uses this embodiment. It is a graph showing the relationship between the position of the infrared shielding part of this embodiment, and detection temperature.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The non-contact temperature sensor 10 of this embodiment receives an infrared ray radiated from an object to be measured, and uses the infrared detection temperature sensing element 20a and the temperature compensation temperature sensing element 20b to convert the energy of the infrared signal into an electrical signal. It is a sensor module that converts to As shown in FIG. 1, the non-contact temperature sensor 10 includes a flexible printed circuit board 12, a housing 14 that houses the flexible printed circuit board 12, and lead wires that take out electrical signals from the flexible printed circuit board 12 to the outside of the housing 14. 16 and a slide type sensitivity adjusting member 18, and an infrared detection temperature sensing element 20 a and a temperature compensation temperature sensing element 20 b (not shown) are attached to the flexible printed circuit board 12.

  The flexible printed circuit board 12 is a resin film that functions as an infrared absorber that absorbs infrared rays emitted from the object to be measured. The outer shape of the resin film is substantially rectangular, and a conductor pattern for electric wiring (not shown) is formed on the surface. The thickness of the resin film is preferably a thin one having a small heat capacity in order to improve the thermal responsiveness to changes in the amount of absorbed infrared rays. Here, in consideration of the ease of handling in the assembly process, the thickness is about 20 μm. Is selected. The resin film is made of a heat-resistant material such as polyimide, which is suitable for soldering and mounting a surface-mounted infrared detecting temperature sensing element 20a and a temperature compensating temperature sensing element 20b described later. is there. Further, a polymer material in which carbon black or an inorganic pigment is dispersed may be used in order to improve infrared absorption ability.

  The infrared detecting temperature sensing element 20a and the temperature compensating temperature sensing element 20b are elements whose own circuit impedance changes according to the environmental temperature, and use a pair having the same characteristics. Here, an NTC thermistor having a negative temperature characteristic, which is a thermistor whose electric resistance value changes in accordance with a change in its own temperature, is used. Each of the temperature sensitive elements 20a and 20b is a surface mount type element having a short terminal length. When the temperature sensitive elements 20a and 20b are mounted on the flexible printed circuit board 12, the temperature sensitive parts of the temperature sensitive elements 20a and 20b and the flexible printed circuit are used. It is considered that the thermal coupling with the substrate 12 is close.

  The housing 14 includes a case portion 22 and a lid portion 24. As shown in FIG. 1, the case portion 22 includes a substantially rectangular bottom plate portion 26, a rear wall portion 30 erected upward from one short side of the bottom plate portion 26, and a pair of left and right long sides of the bottom plate portion 26. And a pair of side wall portions 32 erected upward. The bottom plate portion 26 is sufficiently long in length and substantially equal in width to the outer shape of the flexible printed circuit board 12. A horizontal upper end surface 30 a is formed on the upper portion of the rear wall portion 30. Horizontal upper end surfaces 32 a and 32 b having slight steps are also formed on the upper portions of the pair of side walls 32, and the height of the upper end surface 32 a on the side away from the rear wall portion 30 is the height of the rear wall portion 30. Is set lower than the upper end face 30a by the thickness of the flexible printed circuit board 12 and a spacer 44 described later. Further, the height of the upper end surface 32 b on the rear wall portion 30 side is set to the same height as the upper end surface 30 a of the rear wall portion 30.

  On the other hand, as shown in FIG. 1, the lid portion 24 includes a flat, substantially rectangular top plate portion 34, a front wall portion 36 erected downward from one short side of the top plate portion 34, and a top plate portion. 26, a side wall portion 38 erected downward from a pair of left and right long sides, and a light guide portion 40 erected upward from a central portion of the top plate portion 34. The top plate portion 34 is a shielding surface 34 a that shields infrared rays emitted from the object to be measured on the upper surface, and a movable adjustment knob 18 c of the sensitivity adjustment member 18 described later is provided near the root of the light guide portion 40. A protruding rectangular slide hole 34b is provided. The inner space surrounded by the top plate portion 34, the front wall portion 36, and the side wall portion 38 is wide enough to accommodate the entire case portion 22 from above. The light guide 40 is a cylindrical wall erected from the periphery of the opening 42 opened in the shape of a long hole near the center of the top plate 34. Further, the inner wall surface of the light guide 40 is provided with a coating that absorbs electromagnetic waves in the infrared region. Further, the shielding surface 34a, which is the outer surface of the top plate portion 34, may be subjected to a coating process for reflecting electromagnetic waves in the infrared region.

  In the lid portion 24, spacers 44 having a thickness substantially equal to the thickness of the sensitivity adjusting member 18 described later are attached to four positions on the inner surface of the top plate portion 14. The position where the spacer 44 is affixed is a position where the spacer part 44 comes into contact with the pair of left and right upper end surfaces 32 a of the case part 22 when the case part 22 is stored in the lid part 24.

  The sensitivity adjusting member 18 includes a holding portion 18a that is a U-shaped thin plate, a thin plate-like infrared shielding portion 18b provided between two tip portions of the holding portion 18a, and a holding portion that faces the infrared shielding portion 18b. An L-shaped movable adjustment knob 18c that extends from the center of 18a and bends upward in the middle. The surface of the infrared shielding part 18b is subjected to mirror treatment for infrared reflection or coating treatment for electromagnetic wave reflection in the infrared region.

  One end of the lead wire 16 is connected to the conductor pattern of the flexible printed circuit board 12 on which the temperature sensitive elements 20a and 20b are mounted by soldering or the like, and is drawn out of the housing 14. It has a sufficient length. Here, the number of lead wires 16 is three, the potential at one end of the infrared sensing temperature sensing element 20a, the potential at one end of the temperature compensation temperature sensing element 20, and the infrared sensing temperature sensing element 20a and the temperature compensation temperature sensing. The ground potential to which the other end of the element 20b is connected is output.

  Next, the internal structure of the non-contact temperature sensor 10 in the assembled state will be described with reference to FIGS. 1, 3, and 4. As shown in FIGS. 1 and 3, the flexible printed circuit board 12 has the two mounted temperature sensing elements 20 a and 20 b facing downward, and the lead wire 16 faces the rear wall 30 of the case portion 22. The end portions of the pair of long sides are sandwiched and stretched between the upper end surface 32 a of the case portion 22 and the spacer 44 attached to the top plate portion 34. Therefore, the inner portion of the flexible printed circuit board 12 (the portion not sandwiched between the casings 14) is disposed below the inner surface of the top plate 34 by the thickness of the spacer 44, as shown in FIG. A sensitivity adjusting member 18 is accommodated in the space of the gap.

  In addition, with the flexible printed circuit board 12 and the sensitivity adjustment member 18 housed in the housing 14, the infrared detecting thermal element 20 a is disposed at the center of the opening 42 through which the infrared light enters through the light guide 40. The temperature-compensating temperature sensing element 20b is disposed below the top plate portion 34 where infrared rays are shielded. Further, the movable adjustment knob 18 c of the sensitivity adjustment member 18 protrudes upward from the slide hole 34 b of the upper plate portion 34.

  Further, the case portion 22 and the lid portion 24 of the housing 14 are fixed to the inner surface of the upper plate portion 34 by the upper end surface 30a of the rear wall portion 30 and the upper end surface 32b of the side wall portion 32 with screws or the like (not shown). Is done. In addition, three through holes 30b are provided in the upper end surface 30a of the rear wall portion 30, and the lead wires 16 connected to the flexible printed circuit board 12 are drawn out to the outside of the housing 14 through the through holes 30b. It is.

  When the assembled non-contact temperature sensor 10 is viewed from above, the infrared shielding portion 18b of the sensitivity adjusting member 18 is exposed from the opening 42 in the light guide 40 as shown in FIG. And the position of the infrared shielding part 18b can be varied in the range of X1-X2 by sliding the variable adjustment knob 18c to the left and right within the slide hole 34b. When the sensitivity adjustment member 18 is slid, an appropriate space is secured between the flexible printed circuit board 12 and the top plate portion 34 due to the presence of the spacer 44, and therefore the sensitivity adjustment member 18 damages the flexible printed circuit board 12. It can move smoothly. The spacer 44 is effective when the holding portion 18a and the infrared shielding portion 18b of the sensitivity adjusting member 18 are thick, but the spacer 44 may not be provided if the thickness of each portion is thin and there is no problem with sliding. .

  Next, the temperature detection circuit 46 that is an operation circuit of the non-contact temperature sensor 10 will be described with reference to FIG. The non-contact temperature detection circuit 46 connects a series circuit of the infrared detection temperature sensing element 20a and the reference resistor 49 of the non-contact temperature sensor 10 to both ends of the DC power supply 48, and the voltage across the infrared detection temperature detection element 20a is applied to the voltage signal Va. Take out as. Similarly, the series circuit of the temperature compensation temperature sensing element 20b of the non-contact temperature sensor 10 and the reference resistor 50 is connected to both ends of the DC power supply 48, and the voltage across the temperature compensation temperature sensing element 20b is taken out as a voltage signal Vb. . The reference resistors 49 and 50 have the same resistance value, have a small temperature dependency, and use highly accurate resistors.

  The analog voltage signals Va and Vb are converted into digital voltage signals Va (d) and Vb (d) by the analog / digital converter 52 and sent to the microcomputer 54. The microcomputer 54 performs predetermined calculation processing using the characteristic table data indicating the relationship between the voltage signal and temperature stored in the storage device 56 and the voltage signals Va (d) and Vb (d). Temperature information of the object to be measured is obtained based on the difference between the two voltage signals.

  Next, actual operations of the non-contact temperature sensor 10 and the temperature detection system 46 will be described. When infrared light is not incident from the light guide 40, the temperature of the flexible printed circuit board 12 is uniform, so that the resistance values of the two temperature sensitive elements 20a and 20b are equal and the circuit is balanced, so the voltage signals Va and Vb are equal. Thus, the difference (Vb−Va) becomes zero.

  In addition, the resistance values of the two temperature sensitive elements 20a and 20b change equally even when the infrared rays are not incident on the non-contact temperature sensor 10 when the temperature of the usage environment or the surrounding atmosphere changes. However, since the resistance values of the two temperature sensitive elements 20a and 20b increase or decrease equally, the equilibrium state is maintained, the difference (Vb−Va) is maintained at zero, and temperature compensation is performed appropriately.

  On the other hand, when infrared light emitted from the object to be measured enters from the light guide 40 and is absorbed by the portion at the position of the opening 42 of the flexible printed circuit board 12, a thermal sensor for detecting infrared rays by the thermal energy of the portion. The temperature of 20a changes, and its own resistance value changes. Then, the above-described equilibrium state is broken and a difference (Vb−Va) between the two voltage signals is generated. The microcomputer converts the temperature based on the difference between the voltage signals Va (d) and Vb (d) and the voltage signal Vb (d) which is temperature compensation information, using the characteristic table data recorded in the storage device 56 in advance. Then, the surface temperature of the object to be measured is calculated.

  Next, sensitivity variation correction in the production process or the shipping test process of the non-contact temperature sensor 10 will be described. For example, a temperature detection result obtained by detecting a known temperature of an object to be measured having a constant emissivity, such as a black body furnace, using the non-contact temperature sensor 10 and processing the temperature detection circuit 46 is a predetermined standard. It is determined whether or not When the standard is not satisfied, the movable adjustment knob 18c is operated to change the position of the infrared shielding portion 18b, and the voltage signal Va that is the output of the infrared detecting temperature sensing element 20a is changed and adjusted.

  In this embodiment, as shown in FIG. 4, the position of the infrared shielding part 18b can be varied in the range of X1 to X2, and the part where the infrared shielding part 18b of the flexible printed circuit board 12 is located is infrared rays. Since it cannot be absorbed, the relationship between the position of the infrared shielding part 18b and the detected temperature is expressed as a graph in FIG. 6, for example. That is, when the position of the infrared shielding portion 18b is close to the infrared detecting temperature sensitive element 20a, the amount of heat transmitted from the flexible printed circuit board 12 to the infrared detecting temperature sensitive element 20a is suppressed, and the change in the resistance value is reduced. The sensitivity of the temperature sensing element 20a for detection can be equivalently lowered. Similarly, if the position of the infrared shielding part 18b is separated from the infrared detecting temperature sensitive element 20a, the sensitivity of the infrared detecting temperature sensitive element 20a can be increased equivalently. The sensitivity is adjusted by moving the position of the infrared shielding portion 18b little by little, stopping when the temperature detection result calculated by the temperature detection system 46 satisfies a predetermined standard, and applying an adhesive to the slide hole 34b portion, etc. Then, the infrared shielding part 18b is fixed. In this way, the sensitivity of each product of the non-contact temperature sensor 10 can be adjusted uniformly.

  As described above, the non-contact temperature sensor 10 adjusts the position of the infrared shielding part 18b of the sensitivity adjusting member 18 during the operation check test after assembling the members in the production process, thereby detecting the temperature detection sensitivity. Can be easily corrected, the influence of variations in the external dimensions of each member can be canceled, and the temperature detection accuracy of each product can be set uniformly. Furthermore, since this correction method does not change the contour shape and opening area of the opening 42 in the light guide 40, the detection viewing angle can be kept constant. Further, since the infrared shielding portion 18b is configured to shield infrared rays across the opening in the light guide portion in a direction substantially perpendicular to the moving direction, the voltage is changed when the position is changed in the range of X1 to X2. The signal Va changes gently, and the position adjustment of the infrared shielding part 18b is easy.

  Moreover, the effect of the sensitivity correction | amendment by the infrared shielding part 18b can be heightened by performing the surface treatment of infrared reflection on the infrared shielding part 18b of the sensitivity adjustment member 18.

  Further, the structure of the non-contact temperature sensor 10 is obtained by adding the thin sensitivity adjusting member 18 to the structure of the conventional non-contact temperature sensor, so that the outer shape does not increase so much. Further, the structure in which the sensitivity adjusting member 18 is provided with the movable adjustment knob 18c and protrudes from the slide hole 34b to the outside of the housing 14 can be easily realized without complicating the structure of the housing 14.

  Furthermore, by providing the spacer 44 between the flexible printed circuit board 12 and the top plate portion 34 of the lid portion 24, it is possible to easily ensure an appropriate space for the sensitivity adjusting member 18 to slide smoothly.

  In addition, the non-contact temperature sensor of this invention is not limited to the said embodiment, The shape of the opening part in a light guide part may be an oblong hole, a rectangle, a square, etc. whose both ends are semicircular. . Further, regarding the shape of the infrared shielding portion of the sensitivity adjusting member, if an arbitrary constant area portion of the opening is shielded and the change of the voltage signal Va when the position is changed is appropriate, the sensor It can be set freely according to the application and the form of the object to be measured. The spacer may be replaced by a spacer means such as a protrusion integrally formed on the inner surface of the lid portion or a protrusion provided on the surface of the flexible circuit board. Further, a circuit element such as a reference resistor connected to the two temperature sensitive elements to form a bridge circuit may be mounted on the flexible printed circuit board of the non-contact temperature sensor.

DESCRIPTION OF SYMBOLS 10 Non-contact temperature sensor 12 Flexible printed circuit board 14 Housing 16 Lead wire 18 Sensitivity adjustment member 18a Holding member 18b Infrared shielding part 18c Variable adjustment knob 20a Infrared detection temperature sensing element 20b Temperature compensation temperature sensing element 22 Case part 24 Lid Part 34 Top plate part 34a Shielding surface 40 Light guide part 42 Opening part 44 Spacer 46 Temperature detection system 49, 50 Reference resistance

Claims (5)

In a non-contact temperature sensor equipped with a temperature sensing element for infrared detection and a temperature sensing element for temperature compensation,
A casing provided with a top plate portion that forms a shielding surface that shields infrared rays, and a light guide portion that opens a part of the top plate portion and guides infrared rays therein;
A flexible circuit board that is mounted on the conductor pattern on the back side, the temperature sensing element for infrared detection and the temperature sensing element for temperature compensation are housed in the housing with the front side facing the top plate part, and
An infrared shielding part and a holding part for holding the infrared shielding part are provided, and the position relative to the infrared sensing temperature sensitive element can be adjusted between the flexible printed circuit board, the top plate part, and the light guide part. And a sensitivity adjustment member provided in the
The infrared sensing temperature sensing element is disposed in an opening region of the light guide portion of the casing, and the temperature compensation temperature sensing element is disposed in a position hidden behind the shielding surface,
The infrared shielding portion of the sensitivity adjusting member shields an arbitrary constant area portion within the opening region of the light guide portion of the housing and adjusts the position with respect to the temperature sensing element for infrared detection, thereby A non-contact temperature sensor provided so that the sensitivity of the temperature element can be adjusted.   The non-contact temperature sensor according to claim 1, wherein the infrared shielding unit shields infrared rays across the opening region of the light guide unit in a direction perpendicular to a moving direction.   The non-contact temperature sensor according to claim 1, wherein a surface treatment for reflecting electromagnetic waves in an infrared region is performed on a surface of the infrared shielding part.   The non-contact temperature sensor according to any one of claims 1 to 3, wherein the sensitivity adjustment member is provided with a movable adjustment knob operable from the outside of the housing. Spacer means is disposed between the flexible printed circuit board and the top plate part of the casing facing each other, and the spacer means is provided between the flexible printed circuit board, the top plate part, and the light guide part. The non-contact temperature sensor according to claim 1, wherein a space in which the sensitivity adjusting member can slide is secured.

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