LED application

UV light applications
Ultraviolet sterilizatio
Black lamp
Health UV lamp
nail dryer
beauty and health product
UV tester

Ultraviolet (optical definition in physics)
Ultraviolet is a general term for radiation with a wavelength of 100 to 400 nanometers in the electromagnetic spectrum and cannot cause people's vision.
In 1801, a German physicist discovered that on the purple end of the sunlight spectrum, a section of the photographic film containing silver bromide could be light-sensitized, thereby discovering the presence of ultraviolet rays.
Ultraviolet rays can be used for sterilization, however, too much ultraviolet rays can cause skin cancer when entering the body.

Ultraviolet rays are rays of sunlight with a wavelength of 100 to 400 nanometers (nm), and can be divided into UVA (ultraviolet A, wavelength 320 to 400 nanometers, long wave), UVB (wavelength 280 to 320 nanometers, medium wave), UVC (wavelength 100 to 280 nm, short wave) 3 kinds.
Among them, UVA is the most carcinogenic, and the sunburn and sunburn effects are 1000 times that of UVB. UVC is generally blocked by the ozone layer. IR (Infrared) is infrared, which can cause sunburn, microvessel dilation, dermatitis, and promote the carcinogenicity of ultraviolet rays. Ultraviolet radiation will produce a lot of free radicals in the skin, leading to peroxidation of cell membranes, causing melanocytes to produce more melanin, which is distributed upward to the cuticle of the epidermis, causing black spots. Ultraviolet rays can be said to be the biggest culprit causing skin wrinkles, aging, sagging and dark spots.
When ultraviolet rays are irradiated to the human body, it can promote the body's synthesis of vitamin D to prevent rickets. It is the reason that children are often exposed to the sun. Ultraviolet rays also have a sterilizing effect, and the wards in the hospital use ultraviolet rays to disinfect. However, excessively strong ultraviolet rays will harm the human body, so attention should be paid to protection.

Physical source
Ultraviolet rays are generated when the outer electrons of atoms are excited. The main ultraviolet light source in nature is the sun. When the sunlight passes through the atmosphere, ultraviolet rays with a wavelength shorter than 290 nm are absorbed by ozone in the atmosphere.
Artificial ultraviolet light sources have arcs of various gases (such as low-pressure mercury arcs and high-pressure mercury arcs). Ultraviolet rays have a chemical effect to make photographic film sensitive and have a strong fluorescent effect. Fluorescent lamps, various fluorescent lamps, and black light lamps used to lure and kill insects All use ultraviolet rays to excite fluorescent substances to emit light. Ultraviolet rays can also be anti-counterfeiting. Ultraviolet rays also have a physiological role, which can sterilize, disinfect, treat skin diseases and cartilage diseases. Ultraviolet particles are strong and can make various metals produce photoelectric effect.


Physiological effect
When ultraviolet rays illuminate the human body or organism, physiological changes occur. Different wavelengths of ultraviolet light have different physiological effects. According to the biological effects of ultraviolet rays, ultraviolet rays are divided into different wave bands in medical treatment:
The dark spot ultraviolet (curve A) is in the 320-400 nm band;
Erythema ultraviolet rays or health rays (curve B) in the 280-320 nanometer band;
The sterilized ultraviolet (curve C) is in the 200-280 nm band;
Ozone-causing ultraviolet (curve D) is in the 180-200 nm band.

Ultraviolet-induced black spots: Ultraviolet rays with a wavelength of 320 to 400 nanometers are also called long-wave ultraviolet rays. The biological effect of ultraviolet rays in this band is weak, but it irradiates the human body and makes the skin black, and the skin has obvious pigmentation. This is the dark spot effect of ultraviolet rays. Ultraviolet rays in this band can strongly stimulate the skin, accelerate skin metabolism, strengthen skin growth and thicken the skin. A wave of ultraviolet light is an important band for the treatment of skin diseases, such as psoriasis and vitiligo.



Category:
Ultraviolet rays can be divided into near ultraviolet rays UVA, far ultraviolet rays UVB and ultra-short ultraviolet rays UVC according to the wave.

Shortwave UVC
Short-wave ultraviolet rays are referred to as UVC for short, and are ultraviolet rays with a wavelength of 200 to 280 nm (nano). Short-wave ultraviolet rays are absorbed by the ozone layer when they pass through the stratosphere on the earth's surface, and cannot reach the earth's surface. Short-wave ultraviolet rays can have an important effect on the human body, therefore, enough attention should be paid to short-wave ultraviolet rays.

Medium wave UVB
Medium-wave ultraviolet rays are referred to as UVB for short, and are ultraviolet rays with a wavelength of 280 to 320 nm. UVB has a certain physiological effect on human skin. A large part of these ultraviolet rays are absorbed by the skin epidermis and cannot penetrate into the skin. However, due to its high level energy, it can produce strong light damage to the skin, the dermal blood vessels in the irradiated part expand, and the skin can appear redness, blisters and other symptoms. Long-term exposure to the skin can cause erythema, inflammation, and skin aging. In severe cases, it can cause skin cancer. Therefore, the mid-wave ultraviolet rays, also known as the sunburn (red) band of ultraviolet rays, are the ultraviolet bands that should be focused on prevention.

Long wave UVA
Referred to as UVA. It is ultraviolet light with a wavelength of 315 ~ 400nm. Long-wave UV penetrates clothing and human skin far more than medium-wave UV, and can reach the depth of the dermis, and can act on the melanin in the epidermis, causing skin melanin deposition, making the skin black, and protecting against UV rays Protects the skin. Therefore, long-wave UV is also called "tanning section". Although long-wave UV does not cause acute skin inflammation, it has a slow effect on the skin and can accumulate for a long time, which is one of the causes of skin aging and serious damage. [2]

1. UV curing technology
   UV curing technology is to use UV light (main wavelength 365nm, special occasions 254nm) to irradiate UV curing resins such as paints, adhesives or inks containing photo-reactive prepolymers, photo-reactive monomers, photo-initiators in seconds. Unit fast hardening and drying technology. The common thermal drying method and the superposition reaction method in the two-liquid mixing method usually require a few minutes to several hours to dry the resin.
2. UV surface sterilization devices are widely used in food, electronics, semiconductors, liquid crystal displays, plasma TVs, crystal vibrators, precision devices, chemicals, medicine, health care, biology, beverages, agriculture, etc. The UV light source illuminates the surface of food, materials, etc., which has a fast, efficient and pollution-free sterilization effect, thereby maintaining the high quality of the product.

Related Field:

• Chemistry
  Paint curing, pigment curing, photolithography. Instrument analysis: ore, medicine, food analysis.
• Industry
  Application in surface cleaning treatment
  Due to the development of high-power ultra-high-power low-pressure UV discharge tubes, and with the ultra-miniaturization of microelectronics and other products, in the manufacturing process of microelectronics, ultra-precision devices and other products, short-wavelength ultraviolet rays and ozone generated The practical application of dry optical surface treatment technology for ultra-precision cleaning of the surface of its products or improvement of the adhesion and adhesion of its surface is progressing rapidly. In the manufacture of semiconductor devices, liquid crystal display elements, optical products, etc. that need to be improved in yield, the dry optical surface treatment technology in which ultraviolet UV and O3 ozone are used in combination has become an indispensable technical means. As an alternative technology for Freon, the smooth surface cleaning technology will gradually replace the traditional wet technology.
• Biological field
  Promote plant growth and trap mosquitoes.
  The strongest ultraviolet absorption peak of deoxyribonucleic acid (DNA), ribonucleic acid (RNA) and nucleoprotein in bacteria is 254-257nm. After the bacteria absorb ultraviolet rays, it causes DNA strand breaks, causing the cross-linking of nucleic acids and proteins to rupture, killing the biological activity of nucleic acids and causing the death of bacteria. Fast and convenient, no secondary pollution due to no physical contact.

The bactericidal efficiency of ultraviolet rays on common bacteria and viruses (radiation intensity: 30000μW / cm2).

Types of bacteria	Killing objects	Second (s)
Bacteria	Bacillus anthracis	0.3
	Tetanus	0.3
	Shigella	1.5
	E.coli	0.4
	Staphylococcus	1.3
	Mycobacterium tuberculosis	0.4
virus	flu virus	0.3
	Poliovirus	0.8
	Hepatitis B virus	0.8
	Bacillus virus	0.2
Mold spores	Aspergillus niger	0.3-6.7
	Mucor	4.6
	Penicillium	0.9-3.0
Algae	Blue green algae	10-40
	Nematode eggs	3.4
	Chlorella	1.2
	Protozoa	4.0-6.7
Fish disease	White spot	2.7
	Infectious pancreatic necrosis	4
	Viral hemorrhage	1.6

 

• Medical field
  Ultraviolet sterilization, human health exposure, trapping and killing insects, oil fume oxidation, photocontact enzyme (titanium dioxide).
  Ultraviolet sterilization: Short-wave ultraviolet rays are extremely damaging to microorganisms. When ultraviolet rays in this band irradiate bacteria, the nucleoprotein and deoxyribonucleic acid (DNA) of the cells strongly absorb the energy in this band, and the chain between them Open and break, causing bacteria to die. For example, use ultraviolet mercury lamp or metal halide lamp to sterilize air and food.

Health care effect: the health care effect of ultraviolet rays on the human body. After irradiating the human body with the wavelength of 280-320 nanometers, the ultraviolet rays of the human body will produce many active substances in the skin, thereby playing the role of health care. Use ultraviolet radiation to regulate the function of advanced nerves, improve sleep, and lower blood pressure. Frequent exposure to ultraviolet radiation can enhance the phagocytosis of white blood cells and enhance human immune function.

Promote vitamin production: Sun exposure is a source of vitamin D. Another source is food. For example, ultraviolet rays in sunlight are important factors that promote the production of vitamin D by mushrooms. This function is available whether the mushroom is picked or not picked. Therefore, fresh mushrooms should be dried in the sun, and vitamin D supplementation is effective.

When ultraviolet rays strongly act on the skin, photodermatitis may occur, and erythema, itching, blisters, edema, eye pain, and tearing may appear on the skin; severe cases may also cause skin cancer. Ultraviolet rays act on the central nervous system and may cause headache, dizziness, and increased body temperature. Acting on the eye, it can cause conjunctivitis and keratitis, called photo-ophthalmia, and may also induce cataract. The ultraviolet rays generated during the welding process will cause the welder to suffer from electro-optic ophthalmia (which can be cured).

Related Part Numbers:

• BL-LS3535C0G1UVC
• BL-LS3528A0S1UV