What's the use of infrared rays?

Infrared ray is one of the many invisible rays in the sun, which was discovered by the British scientist Huxley in 1800. Also called infrared thermal radiation. He used a prism to decompose sunlight and placed thermometers at the positions of various ribbons, trying to measure the thermal effects of various colors of light. The thermometer located outside the red light has the fastest temperature rise. Therefore, it is concluded that there must be invisible light, that is, infrared light, besides red light in the solar spectrum. It can also be used as a transmission medium. In the solar spectrum, the wavelength of infrared light is greater than that of visible light, and the wavelength is 0.75 ~ 1000 micron ... The infrared light can be divided into three parts, namely the near infrared light with the wavelength of 0.75 ~ 1.50μ m; Mid-infrared, the wavelength is between 1.50 ~ 6.0μ m; Far infrared ray, wavelength is between 6.0 ~1000μ m.

The real infrared night vision instrument is photomultiplier tube imaging, which is completely different from the principle of telescope. It can't be used in the daytime, it is expensive and needs power to work.

[Edit this paragraph] Physical properties of infrared rays

In the spectrum, the wavelength from 0.76 to 400 microns is called infrared, which is invisible light. Everything above absolute zero (-273. 15℃) can produce infrared rays. Modern physics calls it thermal rays. Medical infrared rays can be divided into near infrared rays and far infrared rays.

Near-infrared or short-wave infrared, with wavelength of 0.76 ~ 1.5 micron, penetrating into human tissues, about 5 ~10 mm; Far infrared rays or long-wave infrared rays, the wavelength of which is 1.5 ~ 400 microns, are mostly absorbed by superficial skin, and the depth of penetration into tissues is less than 2mm.

[Edit this paragraph] Physical characteristics of infrared rays

1. Thermal effect

Everything is constantly radiating infrared rays. The higher the temperature of an object, the more infrared rays it radiates.

Application of thermal effect:

When the human body is sick, although there seems to be no change outside, due to the abnormal local skin temperature, if the camera is equipped with infrared sensitive film, the skin can be photographed and compared with the photos of normal people, the disease can be diagnosed. The photos taken by this camera are called thermograms.

The most obvious effect of infrared radiation on objects is to generate heat. Keep warm in winter because there are a lot of infrared rays shooting at people from the stove, which can make us feel warm.

According to the thermal effect of infrared, people have also developed an infrared night vision device. Infrared night vision devices can also find people in the dark. At night, people's body temperature is higher than the surrounding vegetation or buildings, so the infrared rays radiated by the human body are stronger than them. It can help people observe, search, aim and drive vehicles at night.

Objects absorb infrared rays while radiating them. After various objects absorb infrared rays, the temperature will rise. We can use the thermal effect of infrared rays to heat things. Infrared oven for home use, warm lamp for bathroom, that is, Yuba and so on.

Object heating

Infrared rays can be used to dry paint on the surface of cars, and also to dry crops such as rice.

Drying paint, rice.

In medicine, you can also use the thermal effect of infrared rays for physical therapy. Under infrared radiation, tissue temperature rises, blood flow accelerates, substance metabolism is enhanced, and the vitality and regeneration ability of tissue cells are improved. The wound will heal easily.

Medical physiotherapy

Another characteristic of infrared ray is its strong penetrating power.

2. Strong ability to penetrate clouds (longer wavelength, easy to diffract)

Because all objects are constantly radiating infrared rays, and the intensity of infrared rays radiated by different objects is different, sensitive infrared detectors are used to receive the infrared rays emitted by objects, and then the received signals are processed by electronic instruments, so that the shape and characteristics of the measured objects can be observed. This technology is called infrared remote sensing technology, which can survey geothermal energy, find water, monitor forest fires and estimate crop growth and harvest on satellites. There is also the weather forecast that we should pay attention to every day, which is also the infrared remote sensing technology.

infrared remote sensing

In the war, when the enemy plane flew into our position, the infrared telescope had received a lot of infrared radiation from its engine, which generated current in the photoelectric converter of the telescope, and then generated visible light from the current. So the plane in the dark shows its original shape in the mirror.

The TV remote control we use every day also uses infrared rays. There is an infrared light emitting diode on the front of the remote controller. Pressing different keys can emit different infrared rays to realize remote control of the TV.

Infrared remote control

[Edit this paragraph] The physiological and therapeutic effects of infrared rays.

Reflection and absorption of infrared rays by human body

After infrared rays irradiate the body surface, one part is reflected and the other part is absorbed by the skin. The degree of skin reflection to infrared rays is related to pigmentation. When irradiated with infrared rays with a wavelength of 0.9 micron, skin without pigmentation reflects about 60% of energy. Colored skin reflects about 40% energy. When irradiated by long-wave infrared rays (wavelength 1.5 microns or more), most of them are reflected and absorbed by superficial skin tissues, and the depth of penetration into the skin is only 0.05 ~ 2 mm, so they can only act on the superficial skin tissues. Short-wave infrared rays (wavelength within 1.5 micron) and red near-infrared rays penetrate the tissue deepest, and the penetration depth can reach 10 mm, which can directly act on subcutaneous tissues such as blood vessels, lymphatic vessels and nerve endings of the skin.

Infrared erythema

When infrared rays with sufficient intensity irradiate the skin, infrared erythema may appear, which will disappear soon after stopping irradiation. When the skin is irradiated by high-dose infrared rays for many times, it can produce brown marble-like pigmentation, which is related to the enhancement of melanin formation in the basal cell layer of blood vessel wall by heat.

Therapeutic effect of infrared ray

Infrared therapy is based on the warming effect. Under infrared radiation, tissue temperature rises, capillaries dilate, blood flow accelerates, substance metabolism increases, and tissue cell vitality and regeneration ability improve. When infrared ray is used to treat chronic inflammation, it can improve blood circulation, increase phagocytosis, eliminate swelling and promote inflammation dissipation. Infrared ray can reduce the excitability of nervous system, relieve pain, relieve the spasm of striated muscle and smooth muscle, and promote the recovery of nervous function. When treating chronic infectious wounds and chronic ulcers, it can improve tissue nutrition, eliminate granulation edema, promote granulation growth and accelerate wound healing. Infrared radiation can reduce the exudation of burn wounds. Infrared rays are also commonly used to treat sprain and contusion, promote the dissipation of tissue swelling and hematoma, reduce postoperative adhesion, promote scar softening and reduce scar contracture.

Influence of infrared rays on eyes

Because the eyeball contains more liquid, it absorbs infrared rays strongly, and direct irradiation of infrared rays with a certain intensity will cause cataracts. The occurrence of cataract is related to the action of short-wave infrared rays; Infrared rays with wavelength greater than 1.5 micron will not cause cataract.

The influence of light bath on the body

The action factors of light bath are infrared ray, visible light and hot air. Light bath can make a large area, even the whole body sweat, thus reducing the burden on the kidney, improving the blood circulation of the kidney, which is conducive to the recovery of renal function. Light bath can increase hemoglobin, red blood cells, neutrophils, lymphocytes and eosinophils, and the nucleus shifts slightly to the left; Enhance immunity. Local bathing can improve the blood supply and nutrition of nerves and muscles, so it can promote their functions to return to normal. Whole body light bath can obviously affect the metabolic process in the body and increase the burden of whole body thermal regulation; It also has certain effects on autonomic nervous system and cardiovascular system.

[Edit this paragraph] Equipment and processing method

Infrared light source

1, infrared radiator

The resistance wire is wound on the porcelain rod, and the resistance wire heats up after being electrified, so that the temperature of the carbon rod coated with the resistance wire is raised (generally not more than 500℃), and it mainly emits long-wave infrared rays.

There are two kinds of infrared radiators: field radiators and portable radiators. The power of on-site infrared radiator can reach more than 600 ~ 1000 watt.

In recent years, medical far-infrared radiators have been made in some areas of China, for example, far-infrared radiators made of high-silica elements.

2. Incandescent lamps

Incandescent light bulbs with different powers are widely used as infrared light sources in medical treatment. The temperature of the tungsten wire in the bulb can reach 2000 ~ 2500℃ after being electrified.

Incandescent lamps are used for phototherapy in the following forms:

Incandescent lamps on site: incandescent bulbs with power of 250 ~ 1000 W are used, and metal nets are installed between reflectors for protection. Incandescent lamps on site, usually called sun lamps.

Portable incandescent lamp: low-power incandescent bulbs (mostly below 200W) are installed in a small reflector, which is fixed on a small bracket.

3, light bath device

There are two kinds of local or whole body irradiation. According to the size of the light bath box, 6 ~ 30 40 ~ 60W bulbs are installed in the box. The light bath box is semicircular, and a small metal reflector can be added to the part where the light bulb is fixed in the box. A thermometer should be attached to the whole body light bath box to observe the temperature in the box and adjust it at any time.

Operation method of infrared therapy

1. The patient takes proper posture and exposes the irradiated area.

2, check whether the warm feeling of irradiation site is normal.

3. Move the lamp to the top or side of the irradiation site, and the distance is generally as follows:

When the power is above 500W, the lamp distance should be above 50 ~ 60 cm; Power 250 ~ 300 W, lamp distance 30 ~ 40cm；; The power is below 200W, and the lamp distance is about 20cm.

4, the application of local or whole body light bath, light bath box at both ends need to be covered with cloth. 3 ~ 5 minutes after electrifying, the patient should be asked whether the warm feeling is appropriate; The temperature in the light bath box should be kept at 40 ~ 50℃.

5. Each irradiation 15 ~ 30 minutes, 15 ~ 2 times a day, 15 ~ 20 times as a course of treatment.

6. At the end of the treatment, dry the sweat on the irradiated area, and the patient should rest indoors 10 ~ 15 minutes before going out.

【 Attached 】 Matters needing attention

(1) During the treatment, patients are not allowed to move their positions to prevent burns.

(2) If you feel overheated, flustered, dizzy and other reactions during irradiation, you should immediately notify the staff.

(3) When the irradiation site is close to the eyes or the light can reach the eyes, gauze should be used to cover the eyes.

(4) When the affected part has warm sensation disorder or irradiates fresh scar parts and skin graft parts, it should be applied in low dose, and the local reaction should be closely observed to avoid burns.

(5) Blood circulation disorder, obvious telangiectasia or blood vessels are generally not irradiated by infrared rays.

Selection of irradiation mode and irradiation dose

1, the choice of different irradiation methods

Infrared irradiation is mainly used for local treatment, and in some cases, such as children's whole body ultraviolet irradiation, it can also be combined with infrared irradiation for whole body irradiation. If the thermal effect is deep, incandescent lamp (i.e. solar lamp) is preferred for local irradiation. Local light bath can be used to treat chronic rheumatoid arthritis; The treatment of multiple peripheral neuritis can be treated by whole body light bath.

2. Radiation dose

The dose of infrared therapy is mainly determined according to the characteristics and location of the lesion, the age of the patient and the functional state of the body. When the patient is irradiated by infrared rays, he feels comfortable and warm, and his skin may appear reddish and even erythema. If marbled erythema appears, it is overheating. The skin temperature should not exceed 45℃, otherwise it may cause burns.

Main indications and contraindications

(1) indications

Rheumatoid arthritis, chronic bronchitis, pleurisy, chronic gastritis, chronic enteritis, radiculitis, neuritis, multiple peripheral neuritis, spastic paralysis, flaccid paralysis, peripheral nerve trauma, soft tissue trauma, chronic wound, frostbite, burn wound, bedsore, chronic lymphadenitis, chronic phlebitis, post-injection induration, postoperative adhesion, scar contracture, postpartum hypogalactia, nipple fissure, etc.

(2) Contraindications

There are bleeding tendency, high fever, active tuberculosis, severe arteriosclerosis, angiitis obliterans, etc.

[Attached] Prescription Example

(1) infrared radiation on both knees: the lamp distance is 40cm, 30 minutes, 1 time every day, 7 times. Indications: chronic rheumatoid arthritis

(2) The right chest (lower half) is irradiated with infrared rays at a distance of 50cm for 20 minutes, once a day 1 time, 8 times. Indications: right pleurisy sicca

(3) Solar light irradiates the lumbosacral region: the distance between the lights is 40cm, 20-30 minutes, 1 time every day, 6 times. Indications: lumbosacral radiculitis

(4) Full-body light bath: the temperature in the box is 40 ~ 45℃ for 20 ~ 30 minutes, daily 1 time, 8 times. Indications: Multiple peripheral neuritis

(5) Local light bath on the left calf: 20-30 minutes, daily 1 time, 8 times. Indications: left common peroneal nerve injury

Infrared pollution

In recent years, infrared rays have been widely used in military, artificial satellites, industry, health and scientific research, so infrared pollution problems have also arisen. Infrared ray is a kind of thermal radiation, which will cause high temperature damage to human body. Strong infrared rays can cause skin damage, similar to scalding, burning pain first, then burning. In several different situations, infrared rays can hurt the eyes. The infrared ray with the wavelength of 7500 ~ 13000 A has a high transmittance to the cornea, which can cause damage to the fundus retina. In particular, infrared rays of about 1 1000 angstrom can make anterior media (corneal lens, etc. ) eyes are not damaged and directly cause fundus retinal burns. Almost all infrared rays with the wavelength above 19000 A are absorbed by the cornea, which will cause corneal burns (opacity and white spots). Most of the energy of infrared ray with wavelength greater than 14000 angstrom is absorbed by cornea and intraocular fluid, but it cannot penetrate iris. Only infrared rays below 13000 angstrom can penetrate the iris, causing iris damage. Long-term exposure of human eyes to infrared rays may cause cataracts.

Infrared rays can be manufactured artificially, widely exist in nature, and are also produced during welding, which is harmful to the eyes of welders. Ordinary organisms radiate infrared rays, and the macro effect is heat.

As we know, the cause of heat is the irregular movement of particles that make up matter. This movement also radiates electromagnetic waves, most of which are infrared rays.

1, the sun is almost gone at night, but everything on the earth radiates infrared rays, some strong and some calm. Infrared photography takes pictures by receiving infrared rays emitted by various substances and then displaying them, rather than taking pictures by emitting infrared rays by itself.

2. Infrared perspective and night vision make use of the different properties of infrared respectively. Night vision in front of us is because people can't see infrared rays with naked eyes, but specially designed cameras and night vision devices accept infrared rays, so we think it is black, but cameras can shoot things, because infrared rays are everywhere, which is bright for infrared cameras and night vision devices.

Perspective is the use of infrared wavelengths longer than visible light, which can penetrate some fabrics (such as cotton and nylon) that visible light cannot penetrate, so through certain selective filtering, the images behind these fabrics can be obtained.

Application of infrared ray in life

High temperature sterilization, infrared night vision device, monitoring equipment, infrared port of mobile phone, hotel door card, remote control of car TV, infrared induction of sink, induction door in front of hotel.