JPH08178754A - Clinical thermometer - Google Patents

Abstract

PURPOSE: To obtain a clinical thermometer for measuring the temperature of an object accurately in a short time. CONSTITUTION: A temperature measuring instrument can be built in a case as small as a clinical thermometer by employing a liquid crystal chopper 4 as a modulation means for incident infrared rays at the time of measuring the absolute temperature using a pyroelectric infrared detector 3. When the infrared detector 3 is arranged on the body 1 side, a hollow temperature measuring section 2 having low thermal capacity can be realized. Temperature of ear can also be measured when an opening 1a is provided at the tip of the temperature measuring section.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermometer used for measuring a human body temperature.

[0002]

2. Description of the Related Art Conventionally, a glass tube type thermometer using mercury has been used to measure the body temperature of a human body, but in recent years, an electronic thermometer using a thermistor has been commercialized. This electronic thermometer is rapidly becoming popular because it has the advantages that it does not cause toxicity to the human body when it is damaged and that the body temperature is displayed digitally.

[0003]

By the way, according to the electronic thermometer, since the temperature measuring portion has a structure in which the thermistor is sealed with resin and has a large heat capacity, even if the temperature measuring portion is brought into contact with the temperature measuring portion of the object to be measured. However, it takes a certain amount of time for the temperature measuring unit to reach the same temperature as that of the object to be measured, so that there remains a problem that the time required for temperature measurement is long.

Further, in measuring the temperature of the human body, a temperature measuring method such as measuring the temperature of the eardrum of the ear is adopted as one of the methods for obtaining an accurate measured value of temperature in a hospital or the like. Since an electronic thermometer cannot cope with this, realization of such a simple thermometer capable of measuring the temperature of the eardrum is also desired.

The present invention has been made in view of such circumstances, and an object thereof is to provide a thermometer capable of accurately measuring the temperature of an object to be measured in a short time.

[0006]

In order to achieve the above object, a thermometer according to the present invention is a hollow molded article having an opening 1a at its tip, as shown in FIGS. A main body 1, a hollow member that projects outward from the tip of the main body 1, the inside of which faces the inside of the main body 1 through the opening 1a, and the inside of the main body 1 that faces the opening 1a. And the pyroelectric infrared detector 3 arranged in parallel, and this infrared detector 3
And a liquid crystal chopper 4 arranged between the aperture 1a and the aperture 1a to modulate infrared rays incident on the detector 3, and an arithmetic circuit 1 for obtaining a temperature detection value based on an output signal of the pyroelectric infrared detector 3.
3 and a display section 7 for displaying the detected temperature value.

In the present invention, as shown in FIG. 3, an opening 102b may be provided at the tip of the temperature measuring unit 102.

[0008]

First, the pyroelectric infrared detector can relatively detect changes in the amount of incident infrared light, but a chopper is required to measure the absolute amount of infrared light that is constantly incident, such as temperature measurement. Is. Therefore, in the present invention, as a chopper that modulates the incident infrared rays to the pyroelectric infrared detector, by using a liquid crystal chopper that is extremely small and lightweight as compared with a mechanical chopper, the temperature using the pyroelectric infrared detector is increased. This makes it possible to incorporate the measuring means in a case as small as a thermometer.

Further, in the present invention, the pyroelectric infrared detector 3 is used.
Is placed inside the main body 1, and the temperature measuring unit 2 has a hollow structure to reduce its heat capacity. Therefore, when the temperature measuring unit 2 is brought into contact with the object to be measured, the temperature measuring unit 2 is immediately covered. The temperature becomes the same as that of the object to be measured, and infrared radiation emitted from the inner surface 2a of the temperature measuring unit 2 is detected by the pyroelectric infrared detector 3 through the liquid crystal chopper 4.

As shown in FIG. 3, if an opening 102b is provided at the tip of the temperature measuring unit 102, infrared rays from the eardrum of the ear are directly detected by the pyroelectric infrared detector 3 in the main body 1. This also allows the temperature of the eardrum to be measured.

[0011]

1 is a structural diagram of an embodiment of the present invention, and FIG. 2 is a circuit configuration diagram of the embodiment. The body 1 of the clinical thermometer is a hollow molded article such as plastic and has an opening 1a at its tip, and a temperature measuring unit 2 is attached to its tip. The temperature measuring unit 2 is made of stainless steel or the like into a thin cap shape, and a blackened film such as gold black or platinum black is formed on its inner surface 2a by vacuum deposition or the like.

A pyroelectric infrared detector 3 is provided inside the main body 1.
Is arranged to face the opening 1a, and a lens 5 and a liquid crystal chopper 4 are sequentially arranged between the pyroelectric infrared detector 3 and the opening 1a. The liquid crystal chopper 4 is a modulation element of the type that modulates in the infrared region by utilizing the electro-optical effect of the ferroelectric liquid crystal, and is opened and closed by the drive circuit 8 at a modulation frequency of several tens Hz.

The output signal of the pyroelectric infrared detector 3 is the substrate 6
It is guided to the temperature detection circuit mounted on. As shown in the block diagram of FIG. 2, the temperature detection circuit has a band pass (for example, 1 to 20) that amplifies the output signal of the pyroelectric infrared detector 3.
Hz) type operational amplifier 10 and full-wave rectifier circuit 11 for synchronously rectifying the amplified signal at the modulation frequency of the liquid crystal chopper 3.
And a direct current circuit (DC) 12 and an arithmetic circuit 13.

The arithmetic circuit 13 compares the change in the output signal of the pyroelectric infrared detector 3, that is, the change in the output signal of the direct current conversion circuit 12 with a reference value (30 ° C.) described later and converts it into a temperature detection value. The conversion value is displayed on the display unit 7.
Is displayed in.

In the above structure, the pyroelectric infrared detector 3 has a temperature control means 9 using a Peltier element or the like.
(See FIG. 2), the temperature is held at a constant temperature (for example, 30 ° C.), and the held temperature is used as a reference value for temperature conversion in the arithmetic circuit 13.

That is, in the embodiment of the present invention, the pyroelectric infrared detector 3 is kept at the reference temperature of 30 ° C., and in this state, the absolute value is changed from the change of the output signal when the infrared rays are incident on the detector 3. It is configured to determine the temperature.

In addition to the above structure, the main body 1 has
A battery (not shown) for supplying power to each functional unit is built in, and each functional unit is turned on / off by a switch (not shown).

Next, the operation of the embodiment of the present invention will be described together with the temperature detection operation. First, the temperature adjustment means 9, the liquid crystal chopper 4, the temperature detection circuit, etc. of the pyroelectric infrared detector 3 are operated by turning on the switch.

When the temperature measuring unit 2 of the thermometer is brought into contact with the temperature measuring portion of the object to be measured, since the temperature measuring unit 2 has a small heat capacity, the temperature of the object to be measured immediately becomes the temperature of the object to be measured. An amount of infrared rays corresponding to the temperature radiates from the temperature measuring section 2, the infrared rays enter the main body 1 through the opening 1a, pass through the lens 5 and the liquid crystal chopper 4, and enter the pyroelectric infrared detector 3. As a result, the output signal of the pyroelectric infrared detector 3 changes according to the amount of incident infrared rays, and the degree of the signal change is converted into temperature by the arithmetic circuit 13 and displayed on the display unit 7.

FIG. 3 is a structural diagram of another embodiment of the present invention. What should be noted in this example is that an opening 102b is provided at the tip of the temperature measuring unit 102 as shown in FIG. 3 (A), and thus the tip of the temperature measuring unit 102 is opened. By inserting the temperature measuring unit 102 into the ear canal of the ear as shown in FIG. 3 (B), the eardrum directly faces the visual field of the pyroelectric infrared detector 3, and the emitted infrared rays are emitted from the eardrum. It can be directly detected by the pyroelectric infrared detector 3 through the opening 102b. However, in this example, the infrared radiation emitted from the inner surface of the temperature measuring unit 102 is the pyroelectric infrared detector 3
When incident on, the temperature detection value of the eardrum is affected, so the temperature measuring unit 102 is made of plastic or the like in order to reduce the effect as much as possible.

Although the liquid crystal chopper 4 and the lens 5 are separate components in the above embodiments of the present invention, when the opposite cell made of silicon is used as the liquid crystal chopper 3, the lens 5 is attached to the cell. It may be integrally formed.

Further, in the above embodiments, the pyroelectric infrared detector 3 is maintained at a constant temperature, and the held temperature is used as the reference value for temperature conversion. However, the present invention is not limited to this. For example, a temperature compensating temperature sensor may be provided and the detected temperature may be used as a reference value.

Furthermore, the thermometer of the present invention can be used not only for measuring the body temperature of the human body but also for measuring the body temperature of other animals.

[0024]

As described above, according to the present invention,
Since a liquid crystal chopper is used as a means for modulating the incident infrared rays for using the pyroelectric infrared detector for measuring the absolute temperature, it becomes possible to incorporate these temperature measuring devices in a small case such as a thermometer, Moreover, since the infrared detector is arranged on the main body side and the temperature measuring unit is hollow and has a structure with a small heat capacity, it is possible to realize a thermometer with a shorter temperature measuring time than the conventional electronic thermometer. .

If the thermometer of the present invention is provided with an opening at the tip of the temperature measuring portion, it can be used as a thermometer for the eardrum of the ear, and in this case, the body temperature can be measured more accurately and in a short time. Further, since it becomes possible to measure the temperature of the eardrum in this way, when measuring the body temperature of a person who has difficulty contacting the temperature measuring unit with the armpit or mouth such as a bedridden patient, the thermometer of the present invention is used. If used, the body temperature can be measured from the temperature of the eardrum just by inserting the temperature measuring unit into the ear, and the effect that the temperature measurement is very simple can be achieved.

[Brief description of drawings]

FIG. 1 is a structural diagram of an embodiment of the present invention.

FIG. 2 is a circuit configuration diagram of the embodiment.

FIG. 3 is a structural diagram of another embodiment of the present invention.

[Explanation of symbols]

 1 Main Body 1a Opening 2,102 Temperature Measuring Part 102b Opening 3 Pyroelectric Infrared Detector 4 Liquid Crystal Chopper 5 Lens 6 Substrate 7 Display 8 Drive Circuit 9 Temperature Control Means 10 Operational Amplifier 11 Full Wave Rectifier 12 DC Directing 13 Operation circuit

Claims (1)

[Claims] 1. A temperature-measuring unit, the interior of which is a hollow-molded product having an opening at its tip and a hollow member projecting outward from the tip of the body so that the inside faces the inside of the body through the opening. A pyroelectric infrared detector disposed inside the main body so as to face the opening, and a liquid crystal disposed between the infrared detector and the opening to modulate infrared rays incident on the detector. A thermometer comprising a chopper, a calculation means for obtaining a temperature detection value based on the output signal of the infrared detector, and a display section for displaying the temperature detection value.