JP2007024596A - Electronic thermometer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To raise a temperature detection speed by reducing heat capacity of a thermistor and parts around the thermistor. <P>SOLUTION: The electronic thermometer comprises a case 2 made of resin, a thermistor 13 provided to the end 2e of a case 2 for detecting the temperature of a portion to be detected and a cap part 3 made of a metal mounted on the end 2e of the case 2 so as to cover the thermistor 13. A blast process is applied to the inner surface of the cap part 3. The length of the part where the cap part 3 at the end 2e of the case 2 fits is set to 3.5 to 5.0 mm and the end 2e of the case 2 and the cap part 3 are bonded with a bond. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electronic thermometer that measures the temperature of a measurement site using, for example, a thermistor. In particular, the present invention relates to an electronic thermometer capable of predicting an equilibrium temperature in about 30 to 40 seconds from the start of measurement.

In a conventional electronic thermometer, the temperature is detected by a thermistor built in an end portion of a main body case, and the thermistor is covered with a metal cap (see, for example, Patent Document 1).
JP 2004-335793 A JP 2001-066190 A

  Conventionally, the metal cap and the main body case are bonded together and the metal cap and the thermistor are bonded by fitting the metal cap into the tip of the main body case with an adhesive filled therein.

  Here, it goes without saying that the smaller the heat capacity of the thermistor, the faster the temperature detection speed. It becomes so good that it does not intervene (see, for example, Patent Document 2). This heat capacity depends on the amount of adhesive for bonding the metal cap to the thermistor and the main body case, the size of the joint, and so on. It becomes large and the responsiveness of the thermistor to heat deteriorates. That is, a smaller amount of adhesive is preferable for improving the thermal response (in order to increase the temperature detection speed). However, if the amount of adhesive is reduced, the bonding strength of the metal cap to the main body case will decrease.Therefore, it is better to use a thermistor with a small heat capacity or to maintain the bonding strength while reducing the heat capacity around the thermistor. It can be said that it is necessary.

  This invention is made in view of the said subject, The objective is reducing the amount of adhesives, maintaining the joining strength of a metal cap, a main body case, or a thermistor, and making the thermal capacity of a thermistor and its peripheral part small. It is to provide an electronic thermometer that can increase the temperature measurement speed. Another object is to provide an electronic thermometer that is convenient for the user.

  In order to solve the above-described problems and achieve the object, an electronic thermometer according to the present invention includes a case, a sensor provided at an end of the case, which detects the temperature of a measurement site, and covers the sensor. An electronic thermometer including a cap portion attached to an end portion of the case, the inner surface of the cap portion being subjected to blasting, and a length of a portion of the end portion of the case where the cap portion is fitted. The end of the case and the cap were bonded with an adhesive.

  Preferably, the sensor is a thermistor, and the thermistor is fixed by an adhesive filled in the inner surface of the cap portion.

  Preferably, the case is made of resin, and the cap portion is made of metal.

  As described above, according to the present invention, for example, the bonding strength can be maintained while reducing the amount of adhesive for fixing the metal cap to the case and reducing the heat capacity of the thermistor and its peripheral part.

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.
The embodiment described below is an example as means for realizing the present invention, and the present invention can be applied to a modified or modified embodiment described below without departing from the spirit of the present invention.

  1A and 1B are views showing the appearance of an electronic thermometer 100 according to the present embodiment. FIG. 1A is a plan view, FIG. 1B is a side view, and FIG. 1C is a rear view. FIG. 2 is a block diagram showing a configuration of the electronic thermometer 100 according to the embodiment of the present invention. Reference numeral 2 denotes a main body case in which an electronic circuit such as an arithmetic control unit 20 described later, a buzzer 31, a battery (power source unit) 40, and the like are stored. Reference numeral 3 denotes a stainless steel metal cap that houses a temperature measurement unit including a thermistor 13 (see FIG. 2) necessary for body temperature measurement, which is fixed with an adhesive. The main body case 2 and the metal cap 3 are fixed liquid-tightly via an adhesive. Thus, the metal cap 3 causes the thermistor 13 to transfer the body temperature (temperature) and protect the thermistor 13 from external impacts and the like. The main body case 2 is formed of a styrene resin (high impact polystyrene, ABS resin), a polyolefin resin (polypropylene, polyethylene), or the like containing approximately 1 to 2.5% by weight of the silver phosphate silver compound, and the display unit 30. The transparent window 30e that covers is preferably formed by two-color molding. The window 30e is made of transparent resin such as polystyrene and butadiene / styrene copolymer; styrene resin such as poly-2-methylpentene and polypropylene; acrylic resin such as polymethyl methacrylate; cellulose acetate and the like. Cellulose ester; formed from polyester such as polyethylene terephthalate. A power ON / OFF switch 4 is provided on the opposite side of the metal cap 3 of the main body case 2. In addition, a concave portion 2a is provided on the back surface of the main body case 2 so that the electronic thermometer after temperature measurement can be easily grasped and taken out easily. Reference numerals 2b and 2c are anti-slip portions that prevent the electronic thermometer from shifting during temperature measurement. Reference numeral 2d denotes a battery lid cover for replacing the battery. The broken line indicates the storage position of the battery (power supply unit) 40, and the center of gravity is positioned in front of the longitudinal direction in the state where the battery 40 is stored. 30a is a prediction mode display unit that displays a prediction mode, and 30b is a mute mode display unit that displays a so-called mute mode that does not generate a buzzer sound. The electronic thermometer 100 has a width of about 28 mm, a thickness of about 10 mm, and a weight of about 20 gw. The position of the center of gravity, the width, the weight, and the anti-slip portions 2b and 2c are stable when an electronic thermometer is attached to the temperature measuring portion.

  As shown in FIG. 2, the electronic thermometer of the present embodiment detects a temperature, measures the temperature as a digital value, calculates a predicted temperature from the measured temperature, and displays a display 30 and other functional blocks. Are provided with a calculation control unit 20 that controls the display, a display unit 30 that displays body temperature as a measurement result, and a buzzer 31.

  The temperature measurement unit (temperature measurement means) 10 includes a thermistor 13 and a capacitor 14 installed in a temperature sensing unit connected in parallel, and a CR oscillation circuit 11 for temperature measurement. A counter corresponding to the temperature of the thermistor 13 is provided. When the count amount of 16 changes, the temperature is output as a digital amount.

  The arithmetic control unit 20 includes an EEPROM 22a storing parameters necessary for body temperature measurement, a RAM 23 for storing measured temperatures in time series, a ROM 22 storing programs such as prediction formulas, and a display control unit for controlling the display unit 30. 30d, a counter 16 that counts the oscillation signal of the temperature measuring CR oscillation circuit 11, an arithmetic processing unit 21, a counter 16, an arithmetic processing unit 21, and a display control unit 30d that perform calculations under the conditions written in the EEPROM 22a according to the program of the ROM 22. And a control circuit 50 for controlling.

  FIG. 3: shows the flowchart of the body temperature measurement process sequence in the electronic thermometer 100 of embodiment which concerns on this invention. The following operation is triggered by, for example, turning on the power when the power ON / OFF switch 4 is pressed. The following steps are realized by the CPU (arithmetic processing unit) 21 executing a program stored in the ROM 22.

  In step S501, the electronic thermometer is initialized, and detection of the temperature value by the thermistor 13 is started. For example, the temperature value is detected using a sensor every 0.5 seconds. In step S502, for example, the time point at which the temperature value at which the increase from the previous actual measurement value (that is, the actual measurement value before 0.5 seconds) becomes a predetermined value (for example, 1 degree) or more is measured as the reference point (t = 0), and storage in the RAM 23 as specific timing and measured value data (time-series data) is started. In other words, by detecting a rapid temperature rise, it is considered that the measurement person wears a predetermined measurement site. In step S503, it is determined whether or not a decrease in measured temperature is observed during measurement. When the predetermined decrease is observed, the process proceeds to step S511, and when the predetermined temperature decrease is not observed, the process proceeds to step S504.

  In step S504, sequential prediction values are derived (for example, every 0.5 seconds) using the above-described prediction formula using the data stored in step S502. However, unlike the prior art, prediction calculations are performed in parallel based on prediction formulas corresponding to each of the plurality of groups shown in FIG. Note that computation may be performed in parallel for all the groups (here, 10 types of 1 to 8, 11 and 12), or an approximate group is set based on some actually measured values, and some of the surrounding groups are set. The calculation may be performed only for. In step S505, after a lapse of a predetermined time (for example, 25 seconds) from the reference point (t = 0), grouping determination is performed based on a change in each predicted value corresponding to the plurality of groups derived in step S504. Details of this group determination operation will be described later.

  In step S506, the calculation other than the group determined in step S505 is stopped, and the prediction calculation in the determined group is continuously derived for a predetermined time.

  In step S507, when a predetermined time (for example, 30 seconds) has elapsed from the reference point (t = 0), the prediction value at t = 25 to 30 derived as a result of step S506 satisfies a predetermined prediction establishment condition. Check whether or not. For example, it is a check as to whether or not it falls within a predetermined range (for example, 0.1 degree). If the prediction establishment condition is satisfied, the process proceeds to step S508. If the prediction establishment condition is not satisfied, the process proceeds to step S513. In step S508, the buzzer 31 that announces the prediction is sounded, and the process proceeds to step S509. In step S509, the derived predicted value is displayed on the display unit 30. In step S510, it is determined whether an instruction to end display of the temperature measurement result has been received. For example, it may be determined whether or not a power button (not shown) has been pressed, or the display may be automatically terminated when a predetermined time has elapsed from the predicted temperature display. In step S511, the measured data is corrected. Details of this correction processing will be described later. When the correction process is normally performed, the process returns to step S502. On the other hand, if the correction process does not end normally, the process proceeds to step S512. In step S512, a buzzer (not shown) reporting an error is sounded and the temperature detection is terminated. At this time, it is desirable that the buzzer sound is different from that in step S508. In step S513, for example, when a predetermined time (for example, 45 seconds) has elapsed from the start of measurement using a timer or the like, prediction is forcibly established, and the process proceeds to step S507. That is, the prediction value derived at that time is regarded as the final prediction value as it is. Through the above steps, the temperature measuring operation is completed.

[Metal cap joining structure]
FIG. 4 is a cross-sectional view (a) and an external view (b) showing a joint structure between the metal cap 3 and the main body case 2 in the electronic thermometer according to the embodiment of the present invention.

  As shown in FIG. 4 (a), in this embodiment, when the main body case 2 and the metal cap 3 are joined, the inner surface of the metal cap 3 is blasted to form an uneven shape (Rz (10-point average) (Roughness): 1.5 to 2.4 μm) Further, the length of the portion of the end 2e of the main body case 2 where the metal cap 3 is fitted is set to 3.5 to 5.0 mm.

  Here, the blast treatment refers to a treatment in which an abrasive is sprayed at a high speed on the processed surface (the inner surface of the metal cap) to clean, wear or harden the surface.

  Then, an adhesive is applied to the outer peripheral surface of the end portion 2e of the main body case 2 to adhere the metal cap 3, and an amount of the adhesive 13a (15 mg) capable of joining the thermistor 13 to the inner surface of the tip end portion of the metal cap 3. (The degree: about 0.01 J / ° C.) to fix the thermistor 13. As the adhesive 13a, a two-component epoxy adhesive is used. A part (0.5 to 1.0 mm) of the base portion of the metal cap 3 and the end portion 2e of the main body case 2 are strongly fitted (tightened fit).

  Further, the cross-sectional shape of the end 2e of the main body case 2 has a deletion portion 2f obtained by scraping the four portions of the annular outer surface portion into a flat shape as shown in FIG. 4B.

  The metal cap 3 is made of a material such as SUS, and has a thickness of about 0.2 mm, a total length of about 8 mm, and a weight of about 240 to 250 mg. The main body case 2 is made of a resin molded product such as ABS.

  With the above-described configuration, it is possible to achieve a joint strength of 10 kgf or more and a rotational strength (torque) of 1.5 kgm or more, which indicates a pulling strength (tensile strength) indicating difficulty in pulling the metal cap 3. At the same time, the heat capacity of the temperature sensitive part including the metal cap 3 is reduced to about 0.1 J / ° C.

[Modification]
As the shape of the end portion 2e of the main body case 2, in addition to the deleted portion 2f scraped into a flat shape as in the above embodiment, the groove portion 2g in the axial direction and the circumferential direction as shown in FIGS. You may comprise combining the deletion part 2f and the groove part 2h, as shown in the shape which formed 2h, or FIG.5 (c).

  When the metal cap 3 is inserted into the end 2 e of the main body case 2, the adhesive applied to the end 2 e is somewhat scraped off by the peripheral edge of the metal cap 3. When the length of the end 2e of the main body case 2 is smaller than the conventional 3.5 mm, the bonding strength is insufficient. On the other hand, when the length of the end 2e is set to 3.5 to 5.0 mm as in the present embodiment, sufficient bonding strength is obtained even if the adhesive is scraped off when the metal cap 3 is inserted. The amount of adhesive that remains is left.

  That is, a desired joint strength can be obtained without using a means such as a strong fitting by simply extending the length of the end 2e of the main body case 2 by about 1 to 1.5 mm as compared with the conventional case. Therefore, even if the amount of adhesive required for joining the metal cap 3 and the main body case 2 or the thermistor 13 can be reduced as compared with the prior art, the joining strength can be maintained. The temperature detection rate can be increased by reducing the temperature.

It is a figure which shows the external appearance of the electronic thermometer 100 of this embodiment, (a) is a top view, (b) is a side view, (c) is a rear view. It is a block diagram which shows the structure of the electronic thermometer of embodiment which concerns on this invention. The flowchart of the body temperature measurement process sequence in the electronic thermometer 100 of embodiment which concerns on this invention is shown. It is sectional drawing (a) and external view (b) which show the joining structure of the metal cap and main body case in the electronic thermometer of embodiment which concerns on this invention. It is an external view which shows the edge part structure of the main body case of the modification of this embodiment.

Explanation of symbols

2 Main body case 2a Recess 2b, 2c Non-slip part 2d Battery cover 2e End 2f Deletion part 2g, 2h Groove part 3 Metal cap 10 Temperature measurement part 11 Temperature measurement CR oscillation circuit 13 Thermistor 14 Capacitor 15 Resistance 16 Counter 20 Calculation control Unit 21 Arithmetic processing unit 22 ROM
22a EEPROM
23 RAM
24 power supply unit 25 switch unit 30 display unit 30a prediction mode display unit 30b mute mode display unit 30c LED
30d Display control unit 30e Window unit 31 Buzzer 40 Power supply unit 50 Control circuit

Claims (3)

Case and
A sensor that is provided at an end of the case and detects the temperature of the measurement site;
An electronic thermometer comprising a cap portion attached to an end portion of the case so as to cover the sensor,
Blasting the inner surface of the cap part,
The length of the part where the cap part fits at the end of the case is 3.5 to 5.0 mm,
An electronic thermometer, wherein an end of the case and the cap are bonded with an adhesive. The sensor is a thermistor;
The electronic thermometer according to claim 1, wherein the thermistor is fixed by an adhesive filled in an inner surface of the cap portion.   The electronic thermometer according to claim 1, wherein the case is made of resin, and the cap portion is made of metal.

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