Providing noncontact thermometers and carbon dioxide measuring sensors using infrared sensors.SSC 日本語

Noncontact thermometer series

Q. What is infrared?

It is an invisible part of light that is outside the red light. Everything on earth has a temperature and infrared is irradiated from the object if there is a temperature. A person has about 37℃ in temperature and irradiates weak infrared and the sun irradiates strong light and infrared having a temperature of about 6,000℃.

Q. What is far infrared?

When infrared is classified, it is classified into near, middle and far infrared, and they are determined by infrared wavelength (near infrared: 0.7 - 1.4μm, middle infrared: 1.4 - 3μm, far infrared: 3 - 1,000μm).

Q. How is infrared used?

1. Application as a heating method (energy)
It is desired that middle infrared shall be used for heating water, far infrared for rotation spectrum of water molecules, and near infrared for vibration spectrum (Ex.: Chestnut heating, sweet potato heating).

2. Application as infrared measurement technology (information reception)
Technology to capture the infrared irradiated from an object and measure the temperature and temperature distribution on the object.
Technology to irradiate infrared on an object and measure characteristics such as absorption, transmission, reflection and so forth of the infrared.

3. Application as infrared telecommunication technology (information transmission and reception)
Communication using remote controller for electric products and data reading from CDs.

4. Application as infrared laser technology (energy)
Medical laser knives, industrial cutters YAG (1.06μm), CO2 (10.6μm)

Noncontact thermometer series

Q. Difference from the conventional (contact) thermometers and noncontact thermometers

To measure temperatures in the conventional method, the thermometer needs to come in contact with the object. There are two points to be noted when measuring temperatures this way:

1. Bringing the thermometer into contact with the object to be measured
2. Letting the thermometer reach the same temperature as the object to be measured

With this method,

It takes time.
It took about 3 minutes of time with the conventional glass thermometer to measure our body temperatures.
The current electronic thermometers predict the rise in body temperatures with computers and indicate the temperatures earlier in about 1 minute.

It has to be in contact with the object.
It is impossible to measure the temperature if the object to be measured is so small and bringing the thermometer into contact with it may change its temperature, or if the object to be measured is intrinsically dangerous and cannot be contacted (such as electric facility that may cause electric shock), and temperature-indicating tapes (types that would change color depending on the temperature) were used instead. It also caused a problem in terms of sanitation when contact-type thermometers were used in management of heating temperatures and freezing and storage temperatures in fields where food products are handled and so forth.

Noncontact thermometers deliver features as follows;

It does not take time to measure.
Since the infrared irradiated from the object to be measured is received by the sensor, measurement is completed only in the period that takes for the sensor to stabilize (1 - 2 seconds).

There is no need to bring the thermometer into contact with the object. Measurement can be taken regardless of the distance between the object to be measured and the thermometer.
There is a known infrared focusing property (distance coefficient), and measurement can be taken regardless of the distance (temperature indication does not change even if the thermometer is brought closer to or farther from the object) as long as the thermometer stays in the range.

Q. What do we need to be careful about when using noncontact thermometers?

1. Consideration of emissivity
Emissivity changes depending on the material and the surface conditions of the object to be measured, and thus the thermometers are equipped with functions to set up the emissivity.
Although the rough values are shown in literature and so forth, emissivity can be obtained by actually taking measurements with contact-type thermometers or measurement may be taken by affixing a black body tape to set the emissivity to the specified value.

2. Consideration of the size of the object to be measured and the position of the thermometer
This thermometer is equipped with lens and holder to collect infrared from the measurement subject and let it reach the sensor. There are various characteristics to its design depending on the application. Distance coefficient is defined as the indicator of the performance of such functions.
Distance coefficient = Distance between thermometer and object to be measured/diameter of the area of the object to be measured