JP2004249115A - Infrared thermometer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an infrared thermometer which specifically indicates time until a temperature can be measured when the infrared thermometer that was placed under the temperature which can not be measured is placed under the temperature which can be measured. <P>SOLUTION: If a temperature Ta1 measured by a temperature detection element is outside of the range of measurable temperatures (YES at a step 92 or a step 93), a temperature Ta2 is measured again after a predetermined time (a step 95). Waiting time Tw until the temperature is inside of the range of measurable temperatures is calculated (steps 97, 98). The waiting time Tw is indicated on an indicator (a step 99). <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to an infrared thermometer that detects infrared radiation emitted from an object to measure the temperature of the object.

Conventional technology

  One application of an infrared thermometer is an infrared thermometer that measures the temperature (body temperature) of a human body, which generally measures temperature based on infrared rays radiated from a human ear canal, an eardrum, and the like.

  The infrared thermometer includes a probe that can be inserted into a human ear hole, and is provided on a thermometer main body (housing) such that the probe protrudes outside. A waveguide is provided in the probe for guiding infrared radiation radiated from the eardrum or the like (living tissue of a living body) to an infrared sensor disposed in the housing.

  One of the important problems with infrared thermometers is that when the probe is inserted into the ear canal, heat is conducted from the ear canal (human body) through the probe, waveguide, etc. to the infrared sensor, and the output of the infrared sensor becomes unstable. It is becoming. The adverse effect of the ambient heat transmitted from the housing to the infrared sensor cannot be ignored.

  One of the techniques for solving such problems is described in Japanese Patent Publication No. Hei 5-28617 (or US Pat. No. 4,895,164 or WO 90/02521). In the infrared thermometer disclosed in this document, most of the waveguide and the infrared sensor are embedded in a relatively large metal (a heat conductor such as aluminum or copper) heat conduction block (isothermal block means). The heat conduction block (infrared sensor section) is supported in the housing by spacer studs, and the space between the heat conduction block and the housing acts as a heat insulating air layer, reducing heat transfer from a heat source outside the housing to the heat conduction block. . It is stated that the heat conducting block keeps the waveguide and the infrared sensor isothermal at ambient temperature. Further, a low-emissivity barrier such as an aluminum tube is disposed around the outer end of the waveguide, and the barrier is covered with a low thermal conductive cover.

  One of the features of the infrared thermometer is that the measurement time is short (for example, 1 to 5 seconds). Since the heat conduction block in the above document is relatively large, it does not enter a thermal equilibrium state (isothermal state) in such a short time. As long as heat from the human body is transferred to the heat conduction block through the waveguide, the temperature of the infrared sensor also changes. Instability of the output of the infrared sensor is not sufficiently solved.

  A technique directed to solving such a problem is disclosed in International Publication WO 97/24588. In the infrared thermometer described in this document, a thermally conductive tubular body is provided between the probe and the waveguide while insulated from the probe and the waveguide, and heat from the probe is transmitted to the waveguide and the infrared sensor. Is preventing. Since the heat conductive tubular body is provided, the number of parts increases.

  Another problem with the infrared thermometer is that dust and the like enter the waveguide, thereby deteriorating the measurement accuracy.

  Conventionally, in order to solve this problem, silicon glass is bonded so as to cover the opening at the tip of the waveguide. However, silicon glass has problems that it is difficult to process and is expensive, and processing costs are high because an adhesive is used.

  There is also a method in which a resin film is covered on the distal end of the waveguide to close the opening, and the resin film is fixed to the waveguide by a ring member. This method has a problem that it takes time to assemble the resin film and the resin film is easily broken when the dirt is wiped off.

  An infrared thermometer has a temperature range (measurable temperature range) (eg, 10 ° C. to 40 ° C.) in which it can operate properly. An error will be displayed if you try to use the infrared thermometer outside of this temperature range. There is also a problem that it is inconvenient for the user to understand why the error is displayed and how much time is required before it can be used.

  SUMMARY OF THE INVENTION It is an object of the present invention to enable accurate temperature measurement by using a simple structure and minimizing the influence of heat transmitted from the outside (an object such as an ear hole) to a waveguide on an infrared sensor.

  Another object of the present invention is to provide a structure that minimizes the adverse effects of environmental temperature.

  It is a further object of the present invention to effectively prevent dust and the like from entering the waveguide of the infrared thermometer, and to realize this so as to facilitate assembly.

  Further, the present invention specifies the time until the measurement becomes possible when the infrared thermometer, which has been in an unmeasurable temperature environment, is placed in a measurable temperature environment.

  The present invention relates to an infrared thermometer having an infrared sensor disposed in a housing and a waveguide for guiding infrared radiation radiated from an object to the infrared sensor, wherein the infrared sensor is insulated from the waveguide, The infrared sensor and the waveguide are directly or indirectly held in the housing.

  Supporting the infrared sensor in a state insulated from the waveguide includes various modes. The waveguide has an outer end facing the object and an inner end facing the infrared incident surface (sensor surface) of the infrared sensor. One of the above aspects is to separate the inner end of the waveguide from the infrared incident surface of the infrared sensor (provide a gap). There is an air layer between the inner end of the waveguide and the infrared sensor. The air layer has a heat insulating effect.

  The waveguide and the infrared sensor can be held in the housing by a common or separate heat insulating member. A typical example of the heat insulating member (low heat conductive member) is a synthetic resin. The waveguide may be supported by a metal member (a heat conductive member).

  Another mode of supporting the infrared sensor insulated from the waveguide is to dispose the infrared sensor inside the inner end of the waveguide and to keep the infrared sensor away from the inner wall of the waveguide. Also in this case, an air heat insulating layer is provided between the waveguide and the infrared sensor.

  The infrared sensor and the waveguide can be held in the housing by a common or separate insulating member. A heat insulating material may be provided between the infrared sensor and the waveguide to support the infrared sensor.

  In still another embodiment, the infrared sensor can be supported on the inner end of the waveguide by a heat insulating (low thermal conductivity) connecting member. The infrared incident surface of the infrared sensor faces the inner end of the waveguide. The waveguide is supported on the housing by a heat insulating member or metal.

  A mode in which the inner end of the waveguide is in contact with the infrared incident surface of the infrared sensor is also included in a mode in which the infrared sensor is kept insulated from the waveguide. Preferably, a notch is formed at the inner end of the waveguide to reduce the contact area with the infrared sensor.

  As described above, according to the present invention, the infrared sensor is kept insulated from the waveguide (in a state of low thermal conductivity). Conduction of heat from the wave tube to the infrared sensor is suppressed. As a result, the infrared sensor is kept in a thermally stable state.

  The present invention is characterized in that the infrared sensor is insulated (thermally separated) from the waveguide, and does not isothermally heat the infrared sensor and the waveguide. That is, the present invention does not have any equivalent to the heat conduction block or the isothermal block means as in the conventional example. Further, there is no thermally conductive tubular body provided between the probe and the waveguide in a state insulated therefrom. The structure of the infrared thermometer is simplified.

  By holding the infrared sensor with a heat insulating member, the influence of heat conducted from the outside through the housing and other members can be minimized.

  In a preferred embodiment, a probe formed by a heat insulating member surrounding a portion of the waveguide projecting outward from the housing is attached to the housing, and at least a probe is provided between the outer end of the waveguide and the probe. Is provided with a gap. Even when the probe is in contact with the object, the waveguide is inside the probe and separated from the probe (there is an air insulation layer), so that the heat of the object is suppressed from being transmitted to the waveguide.

  The present invention also provides a cap for covering the waveguide of the infrared thermometer.

  This cap has an infrared-transmitting upper bottom portion that covers the outer end opening of the waveguide, and a peripheral wall portion that is continuous with the upper bottom portion and closely adheres to the periphery of the waveguide. Are integrally formed. In a preferred embodiment, the cap is made of a synthetic resin.

  Since the cap (waveguide cap) according to the present invention is formed by integrally forming the infrared-transmitting upper bottom portion and the peripheral wall portion, it is sufficient to simply cover the waveguide with the cap. ， Good assemblability. The cap prevents dust from entering the waveguide.

  In one embodiment, the waveguide cap has an outwardly or inwardly directed flange on its peripheral wall. This flange serves as a stopper for the waveguide cap. Preferably, the waveguide is provided with a portion that engages with the flange. The effect of retaining is further enhanced.

  The present invention further provides an infrared thermometer that can clearly indicate the time until the measurement becomes possible when the infrared thermometer that has been in a temperature environment where measurement is impossible is placed in a temperature environment where measurement is possible.

  This infrared thermometer has an infrared measuring means for measuring the temperature of an object based on the output of the infrared sensor, a temperature measuring means for measuring the internal temperature of the infrared thermometer, and an infrared thermometer for measuring the temperature of the object. Means for judging whether the temperature is within the measurable temperature range of the measuring means, and when the judging means judges that the measured temperature is not within the measurable temperature range, the temperature measured by the temperature measuring means is within the measurable temperature range. It is provided with a means for estimating the waiting time that will enter, and a means for notifying the waiting time estimated by the estimating means.

  In a preferred embodiment, the estimating means detects a temperature change at at least two different points in time and determines a waiting time based on the temperature change and a target temperature (reference) temperature within the measurable temperature range. presume.

  Since the waiting time is notified (displayed), the user can know how much time has elapsed before the infrared thermometer can be used.

  1 and 2 show the infrared thermometer as a whole in a considerably enlarged manner.

  The housing 10 of the infrared thermometer has a substantially cylindrical or flat cylindrical shape as a whole so that it can be easily held by hand, and its tip (a portion where an infrared sensor to be described later is arranged: the left side in FIG. 1) is slightly curved. It becomes thicker toward the front end (front end) and thinner toward the end (rear end) (right side in FIG. 2). The housing 10 is made of a synthetic resin (for example, ABS: acrylonitrile-butadiene-styrene resin).

  A printed wiring board 11 is arranged in the housing 10, and a temperature measuring circuit (including a microprocessor), a display control circuit, and other electronic circuits are assembled on the printed circuit board 11.

  A hole 13 is formed in the upper surface (or front surface) of the tip of the housing 10, and the switch operation button 12 faces the hole 13 from the inside. The button 12 has a curved surface protruding outward. A mounting piece 12a extends from the button 12, and an end of the mounting piece 12a is sandwiched and fixed between two protruding pieces 10a and 10b provided on the inner surface of the housing 10. The button 12 and the mounting piece 12a are integrally formed of resin (for example, ABS resin). The mounting piece 12a has elasticity.

  An operation projection 12b is provided on the inner surface of the button 12. When the button 12 is pressed from the outside toward the inside of the housing 10, the protrusion 12 b hits the actuator of the switch 14 provided on the substrate 11. When the button 12 is pressed once, the power of the above-mentioned temperature measuring circuit is turned on, and the body temperature measurement is started by the second pressing.

  A hole 15 is also formed in the upper surface (front surface) substantially at the center of the housing 10. At a position corresponding to the hole 15, a liquid crystal display (LCD) device 71 is arranged on the substrate 11. That is, the LCD device 71 is housed in the LCD case 72 together with the spacer 74 thereunder, and the case 72 is fixed to the substrate 11. The LCD device 71 is connected to a wiring pattern on the substrate 11 by a rubber connector 75. An LCD cover 73 made of a transparent resin is provided on the LCD case 72. The LCD device 71 displays the measured body temperature and other information. The user can see this information through the LCD cover 73 through the hole 15 in the housing 10.

  The lower surface (rear surface) of the terminal portion of the housing 10 is provided with an entrance for a battery, and a battery cover 16 is detachably attached thereto by screws.

  An infrared sensor 20, a waveguide (wave guide) 30, a probe 40, and a waveguide cap 50 are provided at the tip of the housing 10. In particular, waveguide 30, probe 40 and cap 50 are shown enlarged in FIG.

  The infrared sensor 20 includes a metal case 24, in which an infrared detecting element 21 is provided. A window is opened in the front of the case 24, and a silicon glass 25 that transmits infrared rays is provided so as to cover the window (see FIG. 18 for more details).

  The waveguide 30 has a cylindrical shape made of metal such as copper, and has both ends 30a and 30b open. The open end 30a far from the infrared sensor 20 is called an outer end (or tip), and the open end 30b near the infrared sensor 20 is called an inner end (or end).

  The probe 40 is made of synthetic resin, has a slightly curved conical shape, is cut at the tip, and has a mounting flange 43 formed at the base. A screw hole 45 is formed in the flange 43. At the tip of the probe 40, two steps 41 and 42 are formed on the inner surface. Near the base, a small annular projection 44 for fixing the probe cover 47 is formed.

  The infrared sensor 20 is held by a sensor holder 28. That is, the sensor holder 28 is a bottomed cylindrical member made of a synthetic resin (for example, ABS resin), and has a hole 28A on the bottom surface. The infrared sensor 20 is fitted exactly into the hole 28A. The substrate 17 is fixed to the holder 28. The lead 26 of the infrared sensor 20 is connected to the wiring pattern 18 on the substrate 17. Near the open end 28C of the sensor holder 28, a flange 28B is integrally formed on the outer peripheral surface thereof. If necessary, a temperature detecting element (see reference numeral 22 in FIG. 18) is provided in the infrared sensor 20, or a temperature sensor is provided near the infrared sensor 20.

  The waveguide 30 is held by two waveguide holders 31,32. The waveguide holders 31, 32 are also made of a synthetic resin (for example, ABS resin) and have a substantially cylindrical shape. The holes of the holders 31 and 32 have a constant diameter (except for the concave portions 31D and 32D), and the waveguide 30 fits exactly into the holes. The outer peripheral surfaces of the holders 31 and 32 have different outer diameters in three stages, the portions 31A and 32A having the smallest outer diameters being the longest, and the portions 31B and 32B having the largest outer diameters projecting in a flange shape. Recesses 31D and 32D are formed on the inner peripheral surfaces of the portions 31B and 32B.

  The waveguide 30 is fitted in the hole of the holder 31. At this time, the outer peripheral surface of the waveguide 30 and the inner peripheral surface of the hole of the holder 31 are fixed with an adhesive. Excess adhesive protrudes into the recess 31D. Thereafter, the waveguide 30 is inserted into the hole of the holder 32. The holders 31 and 32 are butted at the large diameter portions 31B and 32B.

  The waveguide holder 32 is placed in the sensor holder 28. The tip portion 28C of the sensor holder 28 contacts the step 32C formed by the large-diameter portion 32B. The sensor holder 28 enters a hole 10A formed at the tip of the housing 10, and its flange 28B contacts the outer peripheral surface of the hole 10A. The distal ends of the waveguide holder 31 and the waveguide 30 are placed in the probe 40, and the small-diameter portion 31 </ b> A of the holder 31 hits the step 42 on the inner surface of the probe 40. The flange 43 of the probe 40 is fixed to the housing 10 by a screw 46. As a result, the probe 40, the waveguide holders 31 and 32 (therefore, the waveguide 30), and the sensor holder 28 (therefore, the infrared sensor 20) are firmly fixed to the tip of the housing 10.

  Almost half of the infrared sensor 20 and the waveguide 30 are located inside the housing 10, and almost half of the probe 40 and the waveguide 30 project outside the housing 10.

  The outer end (tip) 30a of the waveguide 30 is located at substantially the same position as the tip of the probe 40 or slightly inside the tip of the probe 40. The vicinity of the outer end 30a of the waveguide 30 does not come into contact with the probe 40, and a gap (air layer) 33 exists between the vicinity of the tip of the waveguide 30 and the probe 40.

  Further, the inner end (end) 30b of the waveguide 30 faces the sensor surface of the infrared sensor 20 (infrared incident window, that is, silicon glass 25). The inner end 30b of the waveguide 30 is not in contact with the infrared sensor 20, and a gap (air layer) 34 exists between them. It goes without saying that the central axis of the waveguide 30 coincides with the central axis of the infrared sensor 20.

  When measuring the body temperature with this infrared thermometer, the tip of the probe 40 is inserted into the ear canal (external auditory canal). The probe 40 inevitably contacts the ear canal. Generally, since the body temperature is higher than the temperature of the probe 40, heat is transmitted to the probe 40.

  The probe 40, the waveguide holders 31, 32, and the sensor holder 28 are made of synthetic resin. Synthetic trees have extremely low thermal conductivity compared to metals (low heat conduction members), and may be referred to as heat insulation members (in this specification, low heat conduction members and heat insulation members are synonymous). There is a gap (air layer) 33 between the inner surface of the distal end of the probe 40 and the outer end 30a of the waveguide 30, and the air layer 33 also has a heat insulating effect. The wave tube 30 has a structure that is difficult to transmit. Heat is hardly transmitted from the tip of the probe 40 to the waveguide 30 through the holders 31 and 32, and heat is hardly transmitted to the infrared sensor 20 through the sensor holder 28.

  Even if the heat of the ear canal is slightly transmitted to the outer end 30a of the waveguide 30, there is a gap (air layer) 34 between the inner end 30b of the waveguide 30 and the infrared sensor 20, which is insulated. . Therefore, almost no heat is transmitted to the infrared sensor 20.

  In this way, when measuring the body temperature, heat of the human body is hardly transmitted to the infrared sensor 20, and the infrared sensor 20 is hardly affected by the heat from the object. Since the infrared sensor 20 is held by the sensor holder 28 made of synthetic resin (heat insulating member), it is hardly affected by the heat of the surrounding environment.

  Infrared light radiated from the ear canal (tympanic membrane) passes through the waveguide 30 and is guided to the infrared sensor 20, and a correct temperature measurement is performed. If necessary, the measured temperature is corrected based on the output of the temperature sensor (temperature detecting element). The final measured temperature is displayed on the LCD device 71.

  The sensor holders 31 and 32 may be made of metal such as aluminum. In this case, these parts 31 and 32 may be integrated without separating the sensor holder into two members indicated by reference numerals 31 and 32, and the concave portions 31D and 32D are not required. The heat transferred from the ear hole or the like to the waveguide 30 is absorbed by the metal sensor holder, so that heat is hardly transmitted to the infrared sensor 20.

  The probe cover 47 includes a ring 48 made of synthetic resin, and a bag or sheath 49 made of vinyl or another thin synthetic resin sheet attached to the ring 48. The probe cover 47 is for preventing infection of the disease, and is replaced with a new one for each user, that is, disposable. The probe cover 47 is attached to the probe 40 by fitting the ring 48 beyond the annular protrusion 44 provided at the base of the probe 40.

  A switch 60 for detecting that the probe cover 47 has been attached is provided. The switch 60 includes a movable shaft 61. The shaft 61 has two ends 61A and 61B. The end 61A is thin and slidably passes through a hole 45A (through the screw hole 45) formed in the flange 43 of the probe 40. The end 61B slidably passes through a hole formed in the substrate 17, and a contact 63 is attached to the tip. The shaft 61 is constantly urged outward by a spring 62, and an end 61A projects outward from a flange 43 at the base of the probe 40. The contact 63 is in contact with the wiring pattern 64 on the substrate 17 (the switch is on).

  When the probe cover 47 is put on the probe 40, the projecting end 61A of the shaft 60 is pushed by the ring 48 against the force of the spring 62. Thereby, the contact 63 is separated from the wiring pattern 64 (the switch is turned off), and it is detected that the probe cover 47 is attached. The detection of the attachment of the probe cover 47 may be used as the condition for starting the body temperature measurement, or the fact may be displayed by the indicator or the LCD device 71.

  The front cap 19 covers the probe 40, and is detachably attached to an annular protrusion of the flange 43 at the base of the probe 40. The front cap 19 is also made of synthetic resin, and is put on the probe 40 when the infrared thermometer is not used.

  Details of the waveguide cap (cover) 50 are shown in FIGS. The waveguide cap 50 is made of a synthetic resin made of an upper bottom portion 51 that transmits infrared rays, a peripheral wall portion 52 that is continuous from the periphery of the upper bottom portion 51, and a flange 53 that protrudes outward from a tip of the peripheral wall portion 52. , For example, integrally formed of polyethylene or polypropylene. The diameter of the peripheral wall portion 52 gradually increases toward the flange 53. The thickness of the upper bottom part 51 is preferably about 10 to 60 μm, and the thickness of the peripheral wall part 52 and the flange 53 is preferably about 200 to 400 μm.

  On the other hand, referring to FIG. 3, the outer end surface 30a of waveguide 30 has its outer peripheral surface slightly cut and its thickness reduced. The length of the thin portion is substantially equal to the depth of the cap 50. A cap 50 is placed on the thin portion of the outer end 30a of the waveguide 30. This prevents dust and the like from entering the waveguide 30 when the probe cover 47 is replaced.

  The inner diameter of the smallest diameter portion of the peripheral wall portion 52 of the cap 50 is preferably equal to or slightly smaller than the outer diameter of the outer end portion 30a of the waveguide 30. As a result, the cap 50 comes into close contact with the outer peripheral surface of the outer end portion 30a of the waveguide 30.

  The waveguide cap 50 is placed over the waveguide 30 before placing the waveguide 30 with the holder 31 into the probe 40. When the waveguide 30 is inserted into the probe 40, the flange 53 of the cap 50 hits the step 41 on the inner surface of the probe 40. This prevents the cap 50 from falling off.

  The cap 50 placed over the waveguide 30 contacts the probe 40 at its flange 53, but the heat transfer from the probe 40 to the waveguide 30 is small because the cap 50 is also made of synthetic resin.

  Instead of providing the step (retaining projection) 41 on the probe 40, the flange 53 of the cap 50 may be brought into contact with the inner surface of the probe 40 with an appropriate force, or an annular groove may be formed on the inner surface of the probe 40. The flange 53 of the cap 50 may be fitted into the annular groove. At the end of the peripheral wall 52 of the cap 50, an annular projection is provided on the inner peripheral surface so as to project inward, and an annular groove into which the annular projection fits is formed on the outer peripheral surface of the outer end 30a of the waveguide 30. You may. Of course, the flange 53 need not be provided, and the step (retaining projection) 41 need not be formed on the probe 40. The diameter of the peripheral wall portion 52 may be equal at all locations. The cross section of the peripheral wall portion 52 may be a polygon other than a circle, such as a hexagon or an octagon. In this case, the diameter of the circle inscribed in the peripheral wall of the polygonal cylinder is set to be substantially equal to or slightly smaller than the outer diameter of the outer end 30a of the waveguide 30.

  As described above, since the waveguide cap 50 is formed by integrally forming the infrared-transmitting upper bottom portion 51 and the peripheral wall portion 52, the cap 50 may be simply put on the waveguide, and the bonding or bonding of silicon glass or The assemblability is better than the conventional example of fixing the resin film by the ring member. In addition, if the cap 50 has sufficient strength, the cap 50 is not easily broken even when the work of wiping the dirt on the infrared-transmitting upper bottom portion is performed.

  FIG. 6 shows a modification. Here, the structure of each member is shown in a somewhat simplified manner, and the illustration of the waveguide cap, the probe cover, the front cap, and the like is omitted. The same components as those shown in FIGS. 1 to 5 are denoted by the same reference numerals, and redundant description will be avoided. This is true for all variants described below.

  The inner end 30b of the waveguide 30 is inserted and supported in a hole of a waveguide holder 36 made of synthetic resin. The infrared sensor 20 is also fitted and held in the hole of the holder 36. Further, the holder 36 is inserted and supported in a hole of a support block 35 made of metal such as aluminum. The support block 35 is attached to the housing 10 by screws 46A. The probe 40 is attached to the support block 35.

  The inner end 30b of the waveguide 30 is not in contact with the infrared sensor 20 (the insulating air layer 34 exists). Since the waveguide 30 and the infrared sensor 20 are held by a low-thermal-conductivity synthetic resin holder 36, they are supported in an insulated state from each other. The outer end 30a of the waveguide 30 is not in contact with the probe 40. There is an air space 37 between them. That is, it can be said that the air gap 37 and the holder 36 exist between the waveguide 30 and the probe 40 and are arranged in a heat-insulated state.

  In FIG. 7, a connecting member 38 having two cylindrical portions having different diameters is attached to a waveguide holder 36, and the infrared sensor 20 is held at a large diameter portion of the connecting member 38. The inner end 30b of the waveguide 30 is separated from the infrared sensor 20 (the air layer 34 exists), and the infrared sensor 20 is insulated from the waveguide 30.

  FIG. 8 is different from the structure shown in FIG. 6 in that the inner end 30 b of the waveguide 30 is in contact with the infrared sensor 20. Since the surface area of the end face of the inner end 30b of the waveguide 30 is small, heat conduction is not large even in such contact. Such a mode is also included in the concept that the infrared sensor 20 is insulated from the waveguide 30.

  FIG. 9 is different from the structure shown in FIG. 7 in that the inner end 30b of the waveguide 30 is in contact with the infrared sensor 20, but this embodiment is also based on the concept that the infrared sensor 20 is insulated from the waveguide 30. Shall be included.

  FIGS. 10a and 10b show the embodiment shown in FIGS. 8 and 9 in order to minimize the contact area between the inner end 30b of the waveguide 30 and the infrared sensor 20 (when the waveguide 30 contacts the infrared sensor 20). In order to increase the heat insulation effect as much as possible), a short cutout 30c or a triangular cutout 30d is formed at the inner end 30b. The shape of the notch may be any shape such as a semicircle.

  In the infrared thermometer shown in FIG. 11, the infrared sensor 20 is provided inside the inner end 30b of the waveguide 30 supported by the holder 36 at a distance from the inner surface of the waveguide 30 (by providing a gap or an air layer 34A). T) is located. The infrared sensor 20 is mounted on a substrate 17A fixed to a holder 36.

  In FIG. 12, the infrared sensor 20 is supported in the waveguide 30 via a heat insulating material 39 such as styrene foam. Also in this embodiment, the infrared sensor 20 is insulated from the waveguide 30.

  FIG. 13 shows a tapered waveguide 30A that becomes thinner toward the outer end 30a in the configuration of FIG. There is an air layer 34 between the inner end 30b of the waveguide 30A and the infrared sensor 20.

  14 to 17c show modifications of the waveguide cap.

  FIG. 14 shows an embodiment in which a cap (probe cap) 54 is placed not on the waveguide 30 but on the tip of the probe 40. The cap 54 also has an infrared-transmitting upper bottom portion and a peripheral wall portion extending from the upper bottom portion integrally formed of a synthetic resin.

  A waveguide cap 50A shown in FIG. 15 has a notch 53a formed in a flange 53. The area of the flange 53 that contacts the inner surface of the probe 40 is reduced, and the amount of heat transmitted from the probe 40 to the waveguide 30 via the flange 53 is reduced (heat conduction is deteriorated).

  In FIG. 16, instead of the flange 53, several projections 53b radially separated from each other are provided on the cap 50B.

  In the cap 50C shown in FIG. 17A, a large number of circular holes 52a are formed in the peripheral wall portion 52. In FIG. 17B, a number of slits 52b are formed in the peripheral wall portion 52. FIG. 17c shows a cap 50E having a mesh-shaped peripheral wall portion 52A. As described above, by providing holes and slits in the peripheral wall of the cap, or by forming the peripheral wall with a mesh, the contact area with air is increased, and the heat radiation effect is enhanced.

  Figures 18 and 20 show how much time has passed when an infrared thermometer placed in an environment outside the normal operating temperature range (measurable temperature range) was moved to an environment within the measurable temperature range. This is an embodiment relating to an infrared thermometer that can clearly indicate whether or not it is actually in a measurable state.

  The structure of the infrared thermometer may be any one of the above-described embodiments, or may have a conventional structure.

  The infrared thermometer of this embodiment has a temperature sensor. It is sufficient that the temperature sensor is disposed near the infrared sensor, but a temperature detecting element may be provided inside the infrared sensor as shown in FIG.

  In the infrared sensor 20 shown in FIG. 18, an infrared detecting element 21 is disposed at the center of the substrate 23, and a temperature detecting element 22 is disposed near the infrared detecting element 21. These elements 21 and 22 are covered by a metal case 24 attached to a substrate 23. A silicon glass 25 is provided in a window 24a on the front of the case 24.

  FIG. 19 shows an electric circuit of the infrared thermometer. The voltage output (reference voltage, signal voltage) corresponding to the infrared ray detected by the infrared ray detecting element (infrared ray sensor) 21 is amplified by the amplifier 85, converted to a digital signal by the A / D converter 84, and given to the CPU 80. Similarly, the output of the temperature detecting element (temperature sensor) 22 is also converted into a digital signal by the A / D converter 84 and input to the CPU 80. When the power switch 81 is turned on and the measurement start switch 82 is turned on, the CPU 80 basically performs a body temperature measurement process based on the output of the infrared detecting element 21 and outputs the temperature of the temperature detecting element 22 as necessary. The measured body temperature is corrected in accordance with, and the finally determined measured body temperature is displayed on the display 83. When the power switch 81 is turned on, the CPU 80 performs a process described below based on the output of the temperature detecting element 22 and displays the waiting time on the display 83.

  FIG. 20 shows the processing of the CPU 80 for estimating and displaying whether or not the body temperature measurement is possible when the power switch 81 is turned on, and how long the waiting time for the body temperature measurement is possible if the power switch 81 is not possible. I have.

  The upper limit temperature of the temperature range in which body temperature can be measured (measurable temperature range) is TH, and the lower limit temperature is TL (for example, TH = 40 ° C., TL = 10 ° C.).

  When the power switch 81 is turned on, the output of the temperature detecting element 22 at that time is taken in to determine the temperature Ta1 (step 91). If the measured temperature Ta1 is within the measurable temperature range (TL ≦ Ta1 ≦ TH) (NO in steps 92 and 93), since the body temperature can be measured, the display 83 indicates that measurement is possible. (Step 94), and waits for an input from the measurement start switch 82 before proceeding to the body temperature measurement process.

  If the measured temperature Ta1 is out of the measurable temperature range (YES in step 92 or 93), after a lapse of a predetermined time, the output of the temperature detecting element 22 is taken in again and the temperature Ta2 at that time is measured (step 95). .

  If the temperature environment of the infrared thermometer changes (for example, the thermometer is taken from a cold room where the infrared thermometer is stored to a warm room for measuring the temperature), the internal temperature of the thermometer, that is, temperature detection The output of element 22 is also changing. This amount of temperature change is calculated by ΔTa = | Ta1−Ta2 | / t1 (steps 95 and 96). Here, the time t1 is an elapsed time between the time when the temperature Ta1 is measured and the time when the temperature Ta2 is measured, and may be a fixed time fixed in advance, or the processing from Step 91 to Step 95. The elapsed time up to may be adopted.

  If the current temperature (Ta1 or Ta2) and the change amount ΔTa of the temperature are known, the time Tw required for the temperature to enter the measurable temperature range can be estimated. The function for this estimation is f (Ta1, ΔTa).

  This function f (Ta1, ΔTa) is represented by, for example, a first-order approximation. That is, assuming that the change in temperature has a linear relationship with the passage of time, the function f can be expressed in the simplest form.

  Assuming that the time from when the current temperature Ta1 is lower than the lower limit temperature TL and when the temperature rises and reaches the lower limit temperature TL is a waiting time Tw, Tw is given by the following equation.

  Tw = f (Ta1, ΔTa) = k (TL−Ta1) / ΔTa

  Here, k is a constant, and a value of 1.0 or more is generally used.

  Assuming that the time from when the current temperature Ta1 is higher than the upper limit temperature TH to when the temperature decreases and reaches the upper limit temperature TH is a waiting time Tw, Tw is given by the following equation.

  Tw = f (Ta1, ΔTa) = k (Ta1-TH) / ΔTa

  In the above equation, these intermediate temperatures TM (= (TL + TH) / 2) may be used instead of TL and TH.

  The waiting time Tw can be estimated using the reference voltage output of the infrared detecting element instead of the output of the temperature detecting element.

  When the waiting time Tw is calculated (step 98), the calculated time Tw is displayed on the display 83 (step 99).

  In this way, the user can know the approximate time until the infrared thermometer becomes usable.

It is a partially broken side view which shows the left half of the whole structure of an infrared thermometer. It is a partially broken side view which shows the right half of the whole structure of an infrared thermometer. FIG. 2 is an enlarged sectional view showing a probe, a waveguide, and a waveguide cap shown in FIG. 1. It is sectional drawing which expands and shows a waveguide cap. It is a top view which expands and shows a waveguide cap. FIG. 9 shows a modification and is an enlarged cross-sectional view of a part of an infrared thermometer. FIG. 9 shows a modification and is an enlarged cross-sectional view of a part of an infrared thermometer. FIG. 9 shows a modification and is an enlarged cross-sectional view of a part of an infrared thermometer. FIG. 9 shows a modification and is an enlarged cross-sectional view of a part of an infrared thermometer. 10a and 10b are perspective views showing a modification of the inner end of the waveguide. FIG. 13 is a partially enlarged cross-sectional view of an infrared thermometer, showing still another modification. FIG. 10 is a partially enlarged cross-sectional view of an infrared thermometer, showing still another modification. FIG. 10 is a partially enlarged cross-sectional view of an infrared thermometer, showing still another modification. It is sectional drawing which shows a probe cap. It is a perspective view showing a modification of a waveguide cap. It is a perspective view showing a modification of a waveguide cap. FIGS. 17A to 17C are perspective views showing modified examples of the waveguide cap. FIG. 9 is a cross-sectional view of an infrared sensor, showing another embodiment. FIG. 9 is a block diagram illustrating an electronic circuit of an infrared thermometer according to another embodiment. 14 is a flowchart showing a processing procedure by a CPU according to another embodiment.

Explanation of reference numerals

20 Infrared sensor
21 Infrared detector
22 Temperature detection element
30 Waveguide
30a Outer end of waveguide (tip)
30b Inner end of waveguide
30c, 30d notch
31, 32, 36 Waveguide holder
34 gap
50 Waveguide cap (cover)
51 Top bottom
52 Perimeter wall
53 Flange
80 CPU
82 Measurement start switch
83 Display

Claims (2)

Infrared measuring means for measuring the temperature of the object based on the output of the infrared sensor;
Temperature measuring means for measuring the temperature inside the infrared thermometer;
Means for determining whether the temperature measured by the temperature measuring means is within the measurable temperature range of the infrared measuring means,
Means for estimating a waiting time when the temperature measured by the temperature measuring means will fall within the measurable temperature range when the determining means determines that the measured temperature is not within the measurable temperature range;
Means for notifying the waiting time estimated by the estimating means.   The infrared thermometer according to claim 1, wherein the estimating means estimates the waiting time based on the temperature measured by the temperature measuring means at at least two different time points and the time between the two time points. .

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