Introduction to Ultraviolet Light and Applications of UV LEDs

1.    Classification of Ultraviolet Rays

Ultraviolet refers to wavelengths ranging from 10nm To 400nm the light, Based on the biological effects of ultraviolet radiation, medical applications classify ultraviolet light into different wavelength bands: black-spot ultraviolet (curve A ) At 320 ~ 400  Nano Band; erythema purpura line or health ray (curve) B ) at 280 ~ 320 Nanowave band; sterilizing ultraviolet (curve C ) at  200 ~ 320  Nanowave band; ozone-depleting ultraviolet (curve) D ) at 180 ~ 200 Nanowave band.

2 · Characteristics of ultraviolet rays:

2.1 UVA Band characteristics;

UVA The band has strong penetrating power and can pass through most transparent glass and plastics. The long-wave ultraviolet rays contained in sunlight account for more than... 98% Can penetrate the ozone layer and cloud cover to reach the Earth's surface, UVA It can directly reach the dermis layer of the skin, damaging elastin fibers and collagen fibers, which causes our skin to tan—emitting only radiation that... 365nm Near-ultraviolet light centered on the center , It can be used in applications such as flaw detection, fluorescence inspection, chemical analysis, ore identification, stage decoration, and banknote verification.

2.2 UVB Band characteristics

UVB The band has moderate penetrating power; its shorter-wavelength portion is absorbed by transparent glass. Most of the medium-wave ultraviolet radiation contained in sunlight is absorbed by the ozone layer, leaving only a small fraction to pass through. 2% It can reach the Earth's surface and is particularly intense during summer and in the afternoon. UVB Ultraviolet radiation has an erythematous effect on the human body and can promote mineral metabolism and vitamin synthesis within the body. D It forms naturally, but prolonged or excessive exposure can cause the skin to tan and lead to redness, swelling, and peeling. Mid-wave UV radiation is often used for fluorescent protein detection and certain biological research applications.

2.3 UVC Band characteristics

UVC The band has the weakest penetrating power. It cannot penetrate most types of transparent glass and plastic. Short-wave ultraviolet radiation contained in sunlight is almost entirely absorbed by the ozone layer. Short-wave UV radiation is highly harmful to the human body; even brief exposure can cause sunburn, while prolonged or intense exposure can lead to skin cancer.

3. UV LED Application areas

In UVLED In market applications, UV-A Occupying the largest market share, as high as 90% Its primary application market is curing, covering areas such as nail art, dental treatments, and ink printing. In addition to this, UV-A Also, incorporating commercial lighting can make white clothing appear even whiter.

As for UV-B and UV-C It is primarily used for sterilization, disinfection, medical phototherapy, and other applications, among which... UV-B Primarily medical, UV-C It is for sterilization and disinfection.

3.1 Application areas in light-curing systems

UVA Typical applications of the band include UV curing and UV Inkjet printing, with a representative wavelength of 395nm、365nm， UV LED Light-curing applications are used in industries such as display screens, electronic healthcare, and instrumentation. UV Adhesive curing; industries including construction materials, furniture, home appliances, automobiles, and more. UV Coating curing; industries such as printing and packaging UV Ink curing.

Among them, ultraviolet LED The decorative panel industry has become a major hotspot, with its greatest advantage being the ability to produce eco-friendly panels that are completely free of formaldehyde and energy-efficient. 90% with advantages such as high output, resistance to coin scratches, and overall economic efficiency. This means... UV LED The established market is an application product market that covers all aspects and the entire lifecycle.

3.2  Application fields of light-curing resins

UV-curable resins are primarily composed of oligomers, crosslinking agents, diluents, photoinitiators, and other specific additives. They harden instantly upon exposure to ultraviolet light, triggering a crosslinking reaction in the polymer resin.

In UV LED Under the irradiation of a UV light-curing machine, the UV-curable resin requires virtually no curing time. 10 A second feels like such a long time, basically. 1.2 It can solidify in seconds, faster than traditional methods. UV Mercury lamp curing machines are much faster. .

3.3. Sterilization and Disinfection Field

UVC Ultraviolet rays in the UV-B band, due to their short wavelength and high energy, can rapidly damage microbial organisms. ( Pathogens such as bacteria, viruses, and spores ) In the cell DNA( Deoxyribonucleic acid ) or RNA( Ribonucleic acid ) Its molecular structure prevents cells from regenerating and deprives bacteria and viruses of their ability to self-replicate; therefore, UVC Bandgap products can be widely used for sterilization and disinfection of substances such as water and air.

Currently available deep ultraviolet application products on the market include: LED Deep-ultraviolet portable sterilizer, LED Deep-Ultraviolet Toothbrush Sterilizer, Deep-Ultraviolet LED Contact lens cleaning and sterilization devices, air-based sterilization, clean water-based sterilization, and sterilization of food and object surfaces.

3.4. Medical field

Skin treatment: UVB An important application of the band is in dermatological treatment—specifically, ultraviolet phototherapy.

Scientists have discovered that the wavelength is in... 310nm Ultraviolet radiation on the left and right sides has a strong hyperpigmenting effect on the skin, accelerating skin metabolism and enhancing skin vitality. As a result, it can effectively treat light-induced skin diseases such as vitiligo, pityriasis rosea, polymorphous light eruption, chronic actinic dermatitis, and photodermatitis prurigo. Consequently, in the medical field, ultraviolet phototherapy is currently seeing increasing applications.

Medical devices: UV Glue bonding makes the economic and automated assembly of medical devices easier.

3.5. Military field

Due to UVC The band belongs to the near-ultraviolet region, which is blind to sunlight; therefore, it also has important military applications, such as short-range ultraviolet secure communications, ultraviolet jamming, and ultraviolet warning technologies.

3.6. Plant factory field

According to Researcher Liu Wenke from the Institute of Agricultural Environment and Sustainable Development at the Chinese Academy of Agricultural Sciences, closed-loop soilless cultivation is prone to the accumulation of autotoxic substances. TiO2 Photocatalytic degradation of root exudates and rice husk degradation products in substrate-cultivated nutrient solutions—sunlight contains only 3% UV light and filtering out by covering materials such as glass 60% The above-mentioned methods cannot be applied within facilities. Seasonal vegetable cultivation during winter, characterized by low temperatures and limited sunlight, results in low efficiency and poor stability, making it unable to meet the demands of facility-based, factory-style vegetable production.

Develop artificial light suitable for soilless cultivation in facility horticulture, particularly well-suited for plant factories. TiO2 Photocatalytic systems are in urgent demand and have enormous commercial potential.

3.7. Gemstone identification field

The UV-Vis absorption spectra of different types of gemstones, as well as those of the same gemstone in different colors and of gemstones of the same color but with different coloration mechanisms, all differ from one another. Although some optimally treated gemstones may have colors identical to their corresponding natural counterparts, their absorption spectra differ due to variations in either the coloration mechanism or the coloring agents involved. UV LED It can help identify gemstones and distinguish certain natural gemstones from synthetic ones; it can also differentiate between certain natural gemstones and artificially treated gemstones using ultraviolet light.

3.8. Banknote Recognition

Ultraviolet identification technology primarily uses fluorescent or ultraviolet sensors to detect the fluorescent markings and anti-counterfeiting features on banknotes, as well as their matte surface reactions. This type of identification technology can detect most counterfeit banknotes—such as those that have been washed, bleached, or taped. It is the earliest-developed, most mature, and most widely used identification technology.