JPH0271124A - Optical thermometer - Google Patents

Abstract

PURPOSE:To make a structure simple and small and to easily perform disinfection by using a ball-shaped lens in an optical system. CONSTITUTION:When the leading end 12 of a probe 10 is inserted in a hole part, the infrared rays emitted from the hole part are condensed to the temp.- sensitive part of an infrared sensor 3 by a ball-shaped lens 5. For example, a thermopile is used as the sensor 3 and, as a temp. sensor for compensating the temp. of a cold contact necessary at that time, a thermometric resistor or diode is used. The signals taken out from both of the infrared sensor 3 and the temp. sensor 4 are sent to a processing part 20 and the temp. of an object is calculated from said signals. The temp. value of the object is sent to a display part 30 to be displayed on a liquid crystal display for example.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an optical thermometer using an infrared sensor, and particularly to its light collecting mechanism.

[Prior Art] Mercury thermometers are widely used as thermometers, but digital electronic thermometers are also becoming more popular recently.

Conventional electronic thermometers use a thermistor as a sensor and are often equipped with an arithmetic circuit for calculating temperature values and a digital display, but the time required to measure temperature is 2 to 3 minutes, which is worse than a mercury thermometer. To deal with this, a method has been developed that predicts the final value based on the course of temperature rise during the first minute or so, but with electronic thermometers that use a prediction method, the predicted value does not necessarily match the actual value. There is a problem.

The problem that temperature measurement takes time is also related to the temperature measurement site. The core body temperature of the head, chest, and abdominal cavity is maintained at a predetermined value by the body's regulatory function, but it is difficult to directly measure this, so the rectum, oral cavity, and axillary regions are generally measured. .

Axillary measurements are widely performed, but the armpit is usually in contact with the outside world, and the skin temperature in that area is slightly lower.
When you close your armpit with the thermometer in between, your skin temperature will begin to rise,
The temperature (flat area) will reach a certain level in about 5 minutes, so if you pull out the thermometer and look at it after that, you will be able to get an accurate reading of the axillary area, but if you pull it out earlier than that, the readings will inevitably be slightly lower. .

Another factor related to temperature measurement time is the heat capacity of the sensor section. In a mercury thermometer, the mercury reservoir is warmed by body heat through a glass wall, and the expansion of the mercury is read, so the heat capacity of the heated object is quite large.

Electronic thermometers also use body temperature to warm the metal part that comes into contact with the measurement site, and the thermistor changes its resistance depending on the temperature of the metal part, so the heat capacity of the heated object (metal part) is large.

All of these thermometers are of the contact type, but there are also non-contact types, and JP-A No. 58-88627 ``Non-Contact Oral Thermometer'' is an example. This uses a pyroelectric infrared sensor to collect infrared light emitted from the oral cavity, input it into the sensor, amplify the sensor output, calculate the body temperature based on the reference temperature signal, and display it. Display on the container.

Alternatively, a thermistor is used as the infrared sensor, and the configuration includes a condensing system, a thermistor, an amplifier, an arithmetic unit, a display mechanism, and a reference temperature detector.

In addition, a method for measuring body temperature by inserting it into the ear canal is disclosed in Japanese Patent Application Laid-Open No. 60-25427. Japanese Patent Publication No. 60-216232. JP 60133331, JP 61-117422. There is Japanese Patent Application Laid-Open No. 61-138130. However, the reality is that these have not yet been realized due to the following problems.

JP-A No. 60-25427 only uses an earplug-type body temperature sensor; for example, does it measure body temperature by contact heat transfer of a thermometer such as a thermistor, or does it use something like a Si sensor that detects infrared rays? It is unclear whether Therefore,
Since the measuring means is unknown, it is impossible to construct a thermometer in reality.

Japanese Patent Application Laid-Open No. 60-216232 discloses an earplug-type device that uses a thermistor as a temperature sensor to measure body temperature by contact heat transfer with the external auditory canal. However, since this method is a contact method, it can be easily assumed that the temperature measurement time required is longer than that of an oral electronic thermometer.

JP-A-60-133331 is basically the same as JP-A-60-216232 because it has a sealed ear and uses a thermistor and a transistor sensor as a temperature sensor.

Japanese Patent Application Laid-Open No. 61-117422 is of a type that is inserted into the ear, and uses a thermopile as an infrared detection sensor. The sensor part is kept at a constant temperature, and body temperature is measured using a reference method with a reference temperature source inside the device. Although it is technically an excellent method, it requires keeping the temperature of the sensor part constant,
Having a reference temperature source has the drawback of complicating the configuration and making it difficult to commercialize the product at low cost.

JP-A-61-138130 discloses a method in which infrared rays from the ear canal are guided to a pyroelectric sensor using an optical fiber, but an infrared optical fiber for measuring body temperature has not been developed.

The wavelength band of radiant energy emitted from body temperature is 8 to 13.
μm, and no fiber passes through it. Even if such a thermometer existed, since the fiber itself emits this wavelength, it would be a source of error, making it difficult to create an accurate thermometer using optical fiber, and even if it were possible, it would be extremely expensive.

The present inventor has already invented and filed an application for a "photothermometer" that measures body temperature by detecting infrared rays emitted from the ear canal or the inside of the oral cavity. In this "optical thermometer," infrared rays from the ear are focused onto an infrared sensor using an optical system such as a lens system or a mirror system. Electric signals (hereinafter referred to as signals) from the infrared sensor and the temperature measuring element for temperature compensation are converted into a body temperature value by a signal processing unit and displayed on a display. However, since the sensor and optical system are large, the probe containing them is also necessarily large and complex. An example of this optical thermometer is shown in FIG. As an example of the size, the diameter of the probe tip 12 is 8 mmφ, the diameter of the housing 11 is 20 mmφ,
The length is 100mm, and in addition to this, there is a processing section 20 and a display section 3.
0 is required.

[Problem to be solved by the invention]

Conventional contact-type thermometers have the problem of taking a long time to measure temperature, and the above-mentioned conventional non-contact thermometers that are sensitive to infrared rays have a complicated structure and are expensive. It is difficult to miniaturize because it uses a lens/mirror system.

Alternatively, there are problems such as difficulty in maintaining confidentiality and difficulty in disinfecting the probe.

The present invention solves these problems, is small in size, easy to handle,
The purpose is to provide a non-contact infrared light thermometer that is easy to disinfect.

[Means and effects for solving the problem] In the present invention,
By using a ball-shaped lens in the optical system, a light thermometer is realized that has a simple structure, is compact, and can be easily sterilized.

FIG. 1 schematically shows the present optical thermometer using a ball-shaped lens. In the present invention, a cylindrical container 11 includes a distal end portion 12 (having such dimensions and shape) that is inserted into a hole such as an ear canal or an oral cavity. In Figure 2, the temperature at the tip is measured by the temperature measuring element 4b.
However, in FIG. 1 of the present invention, since the infrared rays emitted from the tip 12 do not reach the thermomobile, such compensation is unnecessary.

When the tip 12 of the probe is inserted into the hole, the infrared rays emitted from the hole are focused by the ball-shaped lens 5 onto the temperature sensing part of the infrared sensor 3. For example, a thermopile is used as the sensor 3, and a temperature sensing resistor, a diode, or the like is used as the temperature sensor 4 for temperature compensation of the cold junction, which is necessary at that time.

Signals taken out from the infrared sensor 3 and temperature sensor 4 are sent to the processing section 20, and the temperature of the object is determined from the signals. The temperature value of the object is sent to the display section 30 and displayed on, for example, a liquid crystal display.

The interior of the signal processing carried out in the processing section 20 is the same as that of the processing section shown in FIG. 2, except for the sensor 4b.

It is so simple that no part corresponding to the arithmetic unit 23 is required.

That is, the infrared sensor 3 generates a voltage Vs=β(T
-T, ) is generated. Here, To is the temperature of the thermomobile itself, which is constantly monitored by the temperature sensor 4, and β is a constant that depends on the measurement temperature range, lens, shape, and solid angle, and is determined by calibrating with a fixed point blackbody furnace. As can be seen from the definition of β, this equation is an approximate equation when the measurement range is narrow. What is being done in the processing unit 20 is to calculate To obtained by the temperature sensor 4 and the output magnetism of the thermopile using the formula 1'
Since it is determined by = + 'l' o, there is β.

In FIG. 1, the processing section 20 is made into a custom LSI, and the display section 30, the battery (included in the processing section 20), and the probe l.
These processing section 20 and display section 30 are placed in
may be separate from the probe.

As a material for the ball-shaped lens 5, a material that transmits infrared rays having a wavelength of 8 to 13 μm well, such as Si, is used. In addition, glasses such as BaFz and CaFz may also be used. What is important is that the infrared rays emitted from the object to be measured are well transmitted. This ball-shaped lens is attached to the tip 12 of the probe, and has a waterproof structure to prevent liquids such as disinfectant alcohol from entering the probe. Therefore 1
After measuring body temperature using a single optical thermometer, the tip can be easily disinfected with alcohol or the like. In the photothermometer shown in FIG. 2, the inside of the probe tip 12 is disinfected (in contrast to the first
Since the optical thermometer shown in the figure can be easily sterilized, it is possible to measure the temperatures of multiple people one after another using two thermometers.

Furthermore, since the photothermometer shown in FIG. 1 uses a ball-shaped lens, the focal length of the lens is small, and the thermometer can be placed immediately behind the lens. Therefore, wasted space after the lens can be omitted, making the entire optical thermometer more compact, as well as eliminating unnecessary radiation from the side wall of the optical path inside the temperature needle, which is common with conventional mirror and lens systems. Deterioration in measurement accuracy can be essentially eliminated, and a structure advantageous for increasing accuracy can be achieved.

〔Example〕

In FIG. 1, a St ball lens with a diameter of 8 InIII is used. The probe, which has a built-in lens, sensor, processing section, and display section, has a diameter of 14 mm and a length of 150 mm.
It is cylindrical. The external shape is shown in Figure 3.

When the tip of the probe is inserted into the ear canal or oral cavity with the power switch 31 turned on and the hold switch 32 is pressed, in this example, the body temperature 2 seconds later is displayed on the liquid crystal display and held.

FIG. 4 shows an example in which the body temperatures of 10 healthy people and 10 people with fever were measured using the optical thermometer and mercury thermometer of the present invention. Since the tip of this optical thermometer is disinfected each time it takes a measurement, it can be handled in the same way as a conventional mercury thermometer even when multiple people use the device. There was also a good correlation with the mercury thermometer.

〔Effect of the invention〕

By using a ball-shaped lens, it is possible to construct a light thermometer that is smaller, easier to use, and easier to disinfect than conventional light body pseudometers. Using this thermometer, you can quickly and safely measure the body temperature of multiple people.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a light temperature 10 using a ball-shaped lens, Fig. 2 is a block diagram of a conventional light body fake meter, Fig. 3 is an external view of a light thermometer using a ball-shaped lens, and Fig. 4 The figure is a graph showing an example of body temperature measured using an optical thermometer using a ball-shaped lens and a mercury thermometer. In FIG. 1, 3 is an infrared sensor, 4 is a temperature sensor, 5 is a ball-shaped lens, 11 is a cylindrical container, and 12 is a probe tip.

Claims (1)

[Claims] 1. A light condensing section that focuses light emitted from the object to be measured onto a temperature sensing section; the temperature sensing section converts the light into an electrical signal, and the temperature of the object to be measured is determined from the electrical signal; In an optical thermometer comprising a calculation unit for calculating and a temperature display unit, the light condensing unit comprises a ball-shaped lens installed at the tip of a cylindrical container to maintain confidentiality,
An optical thermometer characterized in that the temperature sensing section comprises an infrared sensor. 2. The material of the ball lens is Si, BaF_2 or C
The optical thermometer according to claim 1, which is aF_2. 3. The optical thermometer according to claim 1, wherein the infrared sensor is a thermopile.