Understanding UVLED, UVV, UVA, UVB, UVC, Wavelengths, and Their Diverse Applications (A Must-Have Guide)

UV and Wavelength Concepts

Ultraviolet (UV) light refers to the portion of sunlight that is beyond visible light (violet in the spectrum), which is invisible to the naked eye.

UV light is the radiation within the electromagnetic spectrum with wavelengths ranging from 10 nm to 450 nm. It can be divided into four categories based on wavelength: UVV (395–450 nm), UVA (320–395 nm), UVB (280–320 nm), and UVC (200–280 nm).

In the UVLED market, UVA holds the largest market share, accounting for up to 90%. The primary application market is curing, including sectors like nails, dental care, ink printing, and more. Furthermore, UVA has been integrated into commercial lighting, making white clothing appear whiter.

As for UVB and UVC, they are primarily used in sterilization, disinfection, and medical phototherapy. UVB is mainly used for medical purposes, while UVC is used for sterilization.

UVV: This refers to UV light with wavelengths between 395 nm and 450 nm. It is visible to the human eye and is used for curing the deepest layers, contributing to the adhesion of certain formulas. UVV performs well with white and silver conductive pigments and is commonly used in the following curing processes:

• Silver conductive inks
  
  

• Titanium dioxide pigment coatings
  
  

• Adhesives and deep-fill compounds
  
  

Tips: Wavelength

Wavelength refers to the distance a wave travels during one complete vibration cycle. It is the distance between two points of the same phase along the wave's direction of propagation. The formula for wavelength (λ) is λ = uT, where u is the wave velocity and T is the period. Waves of the same frequency travel at different speeds in different media, resulting in varying wavelengths.

Relationship between Frequency and Wavelength
Frequency is the number of waves that pass through a specific location within a fixed time interval. Therefore, from the previous expression for wavelength, the relationship between wavelength and frequency can be obtained as:

                                                           λ = u / v

The unit of propagation speed in the formula is m/s (meters per second), the unit of frequency is Hertz (Hz), and the unit of wavelength is meters. For example, the broadcast frequency used by the first program of the Central People's Broadcasting Station is 639 kHz (kilohertz). The speed of electromagnetic waves in air is the speed of light 3 × 10⁸ m/s. Therefore, the wavelength of the radio waves used in this program can be calculated as:

                         λ = (3 × 10^8 m/s) / (639 × 10^3 Hz) = 469.48 m

 

UV LED Applications in Various Fields

 

1. Curing Applications

 The UVA wavelength range, typically 395 nm and 365 nm, is most commonly used in UV curing and UV inkjet printing. UV LED curing applications cover industries like display screens, electronics, medical devices, materials for construction, furniture, home appliances, automobiles, and more.

Tips: UVA

UVA: Ultraviolet light in the electromagnetic spectrum with wavelengths between 320 and 395 nm. It is the most harmless and common type of ultraviolet light because it has the lowest energy. It is called Black Light or near-ultraviolet light and is commonly used to make fluorescent materials emit ultraviolet light. It is also known as the photochemical line, representing the energy output that produces the maximum polymerization and curing efficiency when used in UV inks. This point is often used to measure whether the UV light source has decayed.

2. Medical Applications

• Skin Treatment: UVB is widely used in phototherapy for skin diseases such as vitiligo, psoriasis, and chronic photodermatitis. UVB light, typically around 310 nm, accelerates skin metabolism and promotes growth.
  
  

• Medical Devices: UV adhesives make the automation of medical device assembly more efficient. Advanced UV LED systems cure solvent-free adhesives in seconds, providing an effective and economical method for bonding in medical device assembly.
  
  

Tips: UVB

UVB (280-320 nm) is a typical destructive UV radiation with enough energy to damage biological tissue, potentially leading to skin cancer. The depletion of the ozone layer has highlighted the importance of reducing exposure time to UVB light.

3. Military Applications

UV radiation, especially in the UVC range, plays a significant role in military applications, such as UV communication, UV interference, and UV warning technologies.

• UV Communication: UV communication has many advantages over conventional methods, including low eavesdropping rate, high resistance to interference, and low detectability, making it a promising technology for secure and mobile communications.
  
  

• UV Interference: Development of UV-guided missiles has driven research into UV interference techniques, specifically for UV-based countermeasures.
  
  

• UV Warning Systems: UV radiation detectors are used to monitor missile exhaust and provide early warnings.
  
  

4. Sterilization and Disinfection

The UVC range (100-280 nm) is highly effective in killing microorganisms such as bacteria and viruses by damaging their DNA or RNA. UVC radiation has been widely used in sterilization applications, including water and air disinfection.
Common UVC products include portable disinfection devices, toothbrush sanitizers, air and water purifiers, food and surface sterilizers. The demand for these products will grow significantly due to increased safety and hygiene awareness.

Tips: UVC

UVC (100-280 nm) has the shortest wavelength and the highest energy. It is highly effective in surface hardening during UV printing processes. New techniques, such as using nitrogen to reduce ozone formation while printing, enhance the efficiency of polymerization and curing processes.

5. Oil Smoke Purification

UV LED-based photochemical oxidation systems are the latest advanced technology for oil smoke purification in the kitchen. These systems, equipped with UV lamps emitting 185 nm and 254 nm wavelengths, can break down grease and odors in kitchen air, offering advantages such as no secondary pollution, reduced fire risks, compact size, and low maintenance costs.

6. Plant Factory Applications

TiO2 photocatalysis can degrade root exudates and rice husk degradation products in substrate-based nutrient solutions. However, only 3% of sunlight is UV, and glass, a common covering material for facilities, filters out over 60% of UV light. This results in low efficiency for photocatalysis under these conditions. Thus, there is a need to develop artificial light systems for plant factories, using TiO2 photocatalysis for better commercial potential in indoor plant cultivation.

7. Gemstone Identification

UV LEDs are used to identify and distinguish between natural and synthetic gemstones based on their UV-visible absorption spectra. UV LEDs help differentiate between treated and untreated gemstones and allow gemologists to accurately assess the quality and type of a gemstone.

8. Waste Gas Treatment

The textile industry in China accounts for around 30% of the total industrial VOC emissions. UV LED-based photocatalytic oxidation of VOCs is a promising method for treating industrial waste gases, offering advantages like small size, high catalytic activity, chemical stability, low cost, and non-toxicity.

9. UV Resin Curing

UV curing resins, consisting of oligomers, crosslinking agents, diluents, photoinitiators, and other additives, can polymerize and harden instantly when exposed to UV light. UV LED curing systems significantly improve curing times, with speeds up to 10 times faster than traditional mercury UV lamps. These resins are used in a variety of applications, including coatings for flooring, plastics, electronics, printing, and optical fiber.

10. Banknote Recognition

UV technology is widely used for counterfeit detection in banknotes. It involves detecting the fluorescence or UV marks printed on currency notes, which are not visible under normal light. UV lights with specific wavelengths are used to ensure authenticity during note counting, ATM deposits, and cash handling processes.

Summary

In the past decade, UVLED technology has transitioned from laboratory research to industrialization, offering mercury-free, precise wavelengths, energy efficiency, and environmentally friendly features. It has gradually replaced traditional mercury lamps in various industries such as healthcare, industrial applications, and environmental protection. UVLED is reshaping modern technology and daily life by enhancing safety, efficiency, and the sustainable development of products ranging from curing materials to advanced communication systems.