HK1018310B - Infrared thermometer - Google Patents

Description

Infrared thermometer

Field of the invention

The present invention relates to an infrared thermometer for measuring a temperature (body temperature) by detecting infrared rays emitted from a biological surface tissue such as an external auditory canal and a tympanic membrane of a human, and more particularly to an internal structure of a probe inserted into a measurement portion such as an external auditory canal.

Background of the invention

An infrared thermometer (thermometer) is generally provided with a probe that protrudes from a thermometer body and can be inserted into an external auditory canal of a person. The probe is provided with an infrared sensor and a waveguide for guiding infrared rays emitted from a biological surface tissue such as an external auditory canal and an eardrum to the infrared sensor.

Fig. 5 schematically shows an example of the internal structure of the probe of the infrared thermometer. In this infrared thermometer, a probe 100 is composed of a hollow cylindrical body having a conical shape, and an infrared sensor 104 is disposed inside a large-diameter end portion fixed to a thermometer body 102. One end of a cylindrical waveguide 106 is fixed to the detection surface of the infrared sensor 104, and the other end of the waveguide 106 is positioned near the small-diameter tip of the probe 100. A temperature sensor 108 for measuring the temperature of the infrared sensor 104 is attached to the infrared sensor 104. The infrared sensor 104 and the temperature sensor 108 are disposed in the main body 102, and connected to a temperature calculation section 110 that calculates the temperature of the measurement object based on the outputs of the sensors 104 and 108. When the thermometer is used to measure body temperature, the probe 100 is inserted into the external auditory canal 112. Thus, the infrared rays radiated from external auditory canal 112 and tympanic membrane 114 reach infrared sensor 104 through waveguide 106, and temperature calculation section 110 calculates the body temperature based on the outputs of infrared sensor 104 and temperature sensor 108.

In the infrared thermometer, if there is a temperature difference between the waveguide 106 and the infrared sensor 104, an error occurs in the measurement result of the infrared sensor 104 due to the temperature difference. To prevent this, the waveguide 106 is made of a metal having high thermal conductivity, and is generally mirror-finished on the inner surface and then gold-plated on the mirror surface. The waveguide 106 and the infrared sensor 104 are connected to each other by heating and melting an end of the waveguide 106 without interposing a heat insulating material therebetween.

However, when the probe 100 is inserted into the external auditory canal 112, a part of the outer surface of the probe 100 inevitably contacts the external auditory canal 112. At this time, since the temperature of the probe 100 is generally lower than the temperature of the external auditory meatus 112, the heat of the external auditory meatus 112 is conducted to the probe 100, and further the heat of the probe 100 is conducted to the waveguide 106, and the temperature of the waveguide 106 is partially raised. As a result, the infrared sensor 104 detects the temperature of the waveguide 106 at the portion where the temperature rises, and an error occurs in the measurement of the body temperature.

In order to solve this problem, japanese patent application laid-open No. 61-117422 discloses a thermometry method for preventing a temperature of a part of a waveguide from becoming higher than a temperature of an infrared sensor during measurement by warming up a probe to a fixed reference temperature before body temperature measurement. However, the external auditory canal and the tympanic membrane are heated by the preheated probe, and the correct body temperature cannot be measured. In addition, the probe is preheated, and thus power consumption is increased. Particularly in a portable thermometer using a battery, the life of the battery is significantly shortened.

In addition, japanese patent application No. 6-502099 (japanese patent application No. 4-504325) discloses an infrared thermometer including an infrared sensor, an ambient temperature sensor, and a waveguide temperature sensor, which uses a method of measuring the ambient temperature and the temperature of an object at multiple points during adjustment of the thermometer, and converting the temperature of the object using the outputs of the respective sensors at that time and an experimentally obtained temperature conversion equation (i.e., calibration conversion). However, the infrared thermometer requires a plurality of temperature sensors, which increases the manufacturing cost. Further, since it is necessary to measure a plurality of ambient temperatures at the time of adjustment, the time required for adjustment is long.

Summary of the invention

The purpose of the present invention is to provide an infrared thermometer capable of accurately measuring the temperature by preventing heat conducted from a probe insertion object (in particular, the external auditory meatus) to the probe from being conducted to a waveguide and an infrared sensor.

In order to achieve the object, an infrared thermometer according to the present invention is a thermometer in which an infrared sensor and a 1 st tube (waveguide) for introducing infrared rays into the infrared sensor are disposed in a probe at a distal end of a thermometer body, characterized in that: a heat conductive 2 nd tube is disposed between the probe and the 1 st tube, and is heat insulated from the 1 st tube and the infrared sensor.

With this infrared thermometer, heat conducted from the probe insertion object (e.g., external auditory canal) to the probe is conducted to the 2 nd tube disposed between the probe and the waveguide tube (1 st tube). Since the 2 nd tube is thermally conductive, heat conducted from the insertion object to the 2 nd tube is dispersed in the 2 nd tube. Therefore, heat conducted from the 2 nd pipe to the 1 st pipe (waveguide), waveguide, infrared sensor, and the like can be suppressed to a minimum. In addition, the waveguide and the infrared sensor can be maintained at the same temperature, and temperature measurement can be stably performed with high accuracy.

In another aspect of the invention, at least a portion of the probe and the 2 nd tube are brought into contact. In this configuration, heat conducted from the inserted object to the probe is quickly dispersed to the 2 nd tube.

In another aspect of the present invention, a heat radiating portion is provided in the 2 nd pipe. In this configuration, the heat conducted from the probe to the 2 nd tube is quickly dissipated, and the waveguide and the infrared sensor can limit the influence on the temperature of the 2 nd tube itself to a minimum, needless to say.

Brief description of the drawings

Fig. 1 is an external perspective view of an infrared thermometer.

FIG. 2 is a sectional view of a temperature detecting portion of the infrared thermometer of the present invention.

Fig. 3 is a schematic cross-sectional view showing another embodiment of the present invention.

Fig. 4 is a sectional view schematically showing another embodiment of the present invention.

FIG. 5 is a sectional view schematically showing the internal structure of the probe of the infrared thermometer in the conventional example.

Best mode for carrying out the invention

Preferred embodiments of the present invention will be described with reference to the accompanying drawings. Fig. 1 shows an appearance of the infrared thermometer, and a main body 12 of an infrared thermometer 10 is provided with a temperature detecting section 14 which protrudes from a box-shaped plane of the main body 12 to form a tip end portion of the main body 12, and a liquid crystal display section 16 which shows a temperature measured by the temperature detecting section 14. The main body 12 is described as being box-shaped, but the temperature detection portion 14 may be provided at the tip portion and may be bent into a cylindrical shape such as "dogleg" shape, a pistol (pistol) shape, or any other shape that can be easily held by a user.

Fig. 2 shows a cross section of the temperature detection section 14. The temperature detection section 14 is provided with a probe 20. The probe 20 has a hollow cylinder 26 formed integrally with a synthetic resin and having a size and shape (for example, a conical shape) suitable for insertion into the external auditory canal 22 of a human, and a flange portion 28 extending radially from a large-diameter proximal end portion of the cylinder portion 26, and is fixed to the thermometer body 12 by the flange portion 28.

A heat diffusion sleeve 30 is concentrically disposed inside the probe 20. The heat diffusion sleeve 30 includes a cylindrical heat dissipation portion 32 disposed on the proximal end side of the probe cylindrical portion 26, a cylindrical heat transfer portion (2 nd tube) 34 extending from one end of the heat dissipation portion 32 to the vicinity of the distal end portion of the probe, and a flange 36 extending radially outward from the proximal end of the heat dissipation portion 32. The heat diffusion sleeve 30 is made of a metal having a high thermal conductivity, such as copper, aluminum, or brass, which can rapidly diffuse and radiate heat transmitted from the probe 20. In addition, in order to reduce heat transfer from the probe 20, the outer peripheral surface of the heat diffusion sleeve 30 is separated from the inner peripheral surface of the probe 20, and an insulating space 38 is formed therebetween. However, the outer peripheral surface of the heat transfer portion 34 on the distal end side is in contact with the inner surface of the probe 20, and the heat of the probe 20 can be rapidly transferred to the heat transfer portion 34 and dispersed.

Inside the heat diffusion cover 30, a sensor cover 42 made of synthetic resin for fixing the infrared sensor 40 is provided. Further, it is desirable that the sensor cover 42 be formed of resin having as low thermal conductivity as possible. The sensor cover 42 includes a case 46 fixed to the thermometer body 12 together with the heat diffusion cover 30 by screws 44. A sensor housing chamber 48 is formed in the case 46, the infrared sensor 40 and an inner cylinder 50 attached to the outer periphery of the infrared sensor 40 are fitted thereto, and the infrared sensor 40 and the inner cylinder 50 are pressed against the heat diffusion cover 30 by an elastic rubber 52, whereby the infrared sensor 40 is fixed.

The heat diffusion cover 30 incorporates a waveguide 60 made of a metal cylinder extending from the detection surface 54 of the infrared sensor 40 to the distal end of the probe. Further, one end portion of the waveguide 60 near the infrared sensor is held and fixed by a cylindrical metal holder 62, and the metal holder 62 is fixed to the detection surface 54 of the infrared sensor 40 by welding or an adhesive, whereby the position of the waveguide 60 can be determined so as to be concentric with the probe 20 and the heat diffusion cover 30. Further, the waveguide 60 exits the heat diffusion sleeve 30, forming an insulating space 64 therebetween. Likewise, the metal seat 62 also moves away from the heat diffusion sleeve 30, forming an insulating space 66 therebetween.

A temperature sensor (thermistor) 68 is fixed to the infrared sensor 40 with an adhesive. The temperature sensor 68 is connected to the arithmetic section 70 so that the temperature information of the infrared sensor 40 detected by the temperature sensor 68 is output to the arithmetic section 70. Similarly, the infrared sensor 40 is also connected to the arithmetic section 70, so that the temperature information detected by the infrared sensor 40 is output to the arithmetic section 70. Further, as shown, a plurality of holes are preferably provided in the housing 46 through which the leads of the sensors 40, 60 are led.

When measuring body temperature with the thermometer 10, the operator holds the body 12 with one hand and inserts the probe 20 into the external auditory canal 22 of the patient or himself as shown in the figure. Then, the infrared rays emitted from the external auditory canal 22 and the tympanic membrane 24 are guided into the waveguide 60 and detected by the infrared sensor 40. Then, the infrared ray sensor 40 outputs a signal corresponding to the intensity of the infrared ray to the operation part 70. The arithmetic section 70 calculates the body temperature based on the outputs from the infrared sensor 40 and the temperature sensor 68, and displays the result on the display section 16.

At the time of body temperature detection, the probe 20 inserted into the external auditory meatus 22 inevitably contacts the external auditory meatus 22 as shown in the drawing. In addition, since the temperature of the probe 20 is generally lower than the body temperature, heat is transferred from the external auditory meatus to a probe portion (generally, a tip portion) contacting the external auditory meatus 22.

The heat is conducted to the heat transfer portion 34 of the heat diffusion sleeve 30 contacting the probe 20, and further to the heat dissipation portion 32. Here, since the heat dissipation portion 32 is made larger in volume than the heat transfer portion 34 and therefore its heat capacity is large, the heat of the heat transfer portion 34 quickly moves to the heat dissipation portion 32. However, since the heat diffusion cover 30 and the waveguide 60 are thermally insulated by the thermal insulation space 64, the heat of the heat diffusion cover 30 cannot be conducted to the waveguide. Further, since the metal holder 62 is externally attached to the waveguide portion near the infrared sensor and the metal holder 62 and the heat diffusion cover 30 are thermally insulated by the thermal insulation space 66, the heat of the heat dissipation portion 32 of the heat diffusion cover 30 cannot be conducted to the infrared sensor 40, the waveguide 60, and the like. Therefore, since the waveguide 60 and the infrared sensor 40 are kept at the same temperature, when the temperature of a part of the waveguide 60 rises, an error in measuring the body temperature is not caused by the influence of the temperature rising part.

In the above-described embodiment, the waveguide 60 is fixed to the infrared sensor 40 by the metal holder 62, but the end of the waveguide 60 may be welded to the infrared sensor 40 by heating, or a disk-shaped flange may be integrally provided at the end of the waveguide 60 and fixed to the infrared sensor 40 by the flange.

In the above embodiment, a part of the heat transfer portion 34 of the heat diffusion cover is brought into contact with the probe 20, but as shown in the schematic of fig. 3, the waveguide 60 may not be brought into contact with the probe 20 at all, or the entire outer periphery of the heat transfer portion 34 may be brought into contact with the probe 20.

In the above embodiment, the heat transfer portion 34 and the heat dissipation portion 32 are formed integrally, but as shown in fig. 4, they may be formed separately and combined to form the heat diffusion jacket 30.

As described above, according to the infrared thermometer of the present invention, since the thermally conductive 2 nd tube thermally insulated from the 1 st tube and the infrared sensor is disposed between the probe and the waveguide tube (1 st tube), the heat conducted from the probe insertion object to the probe is conducted to the 2 nd tube, and the heat conduction to the waveguide tube and the infrared sensor can be suppressed to the minimum. Therefore, the temperatures of the waveguide and the infrared sensor can be kept equal, and stable temperature measurement can be performed. Thus, the measurement accuracy is improved.

In addition, since the probe is brought into contact with at least a part of the 2 nd tube, heat conducted from the inserted object to the probe can be quickly conducted to the 2 nd tube.

Further, by providing the heat dispersing portion in the 2 nd tube, the heat conducted from the probe to the 2 nd tube can be rapidly dispersed, and the waveguide and the infrared sensor can suppress the influence on the temperature of the 2 nd tube itself to a minimum.

Claims (3)

1. An infrared thermometer comprising an infrared sensor and a waveguide for guiding infrared rays to the infrared sensor, the infrared thermometer being disposed in a probe at a distal end portion of a thermometer body, characterized in that:

a thermally conductive 2 nd tube is arranged between the probe and a 1 st tube, which is a waveguide, in a manner insulated from the 1 st tube and the infrared sensor.

2. The infrared thermometer of claim 1 wherein: the probe is in contact with at least a portion of the No. 2 tube.

3. An infrared thermometer according to claim 1 or claim 2 wherein; the 2 nd pipe has a heat radiating portion.