Date:Feb 22, 2021


If you are researching alternative methods of UVC disinfection for your application, you have two options: LEDs and lights. One of the important factors to consider when comparing these options is intensity, which is the amount of light reaching a surface or area. UVC intensity is usually displayed in units of microwatts or milliwatts per square centimeter.


For various reasons, it may be difficult to compare UVC LEDs and mercury-based UVC lamps. Bulbs provide specifications and data based on similar fluorescent lamps, so you usually can't find the specifications you need in the UVC range, degradation and other key information. UVC LEDs are separate light sources and must be designed to meet specific requirements for applications. Unfortunately, this means that until you design and build a UVC LED module and test it next to the lamp, there is almost no comparable information. However, we can make some assumptions about the actual bulb output and use some calculations to understand how these two options compare. When making this comparison, the estimated power output, application requirements, and overall cost should be considered.


Estimated power output

There are various mercury lamps on the market. When searching for UVC lamps, you will usually see that the power is the only power rating displayed in the power rating. This can cause confusion because the wattage of the lamp is the input power. After eliminating the low efficiency of the lamp ballast and the loss due to heat, the actual output of the lamp at 254 nm is 10% to 30% of the input rating. A higher percentage usually applies to higher-quality, larger high-power lamps. For a 10-watt lamp, a good assumption is 1 watt or 1000 mW.


At this point, a direct comparison with a 60 mW UVC LED with an actual output of 265 nm is that you need 17 LEDs. But this is not complete, because we still need to consider the difference in wavelength output. The advantage of LED is that the chemical composition in the semiconductor material can be adjusted to obtain a specific light output, and when the 254 nm output of the lamp is within the sterilization range, the maximum efficiency for most sterilization is 265 nm. . For most microorganisms, the disinfection effect of 265 nm is better.


Application conditions

Application requirements provide a context for when and how UVC LEDs can be better than existing lamp systems. A typical 10W lamp is about 8 inches long, but the length of the light-emitting tube is only 5 inches. One of the advantages of LEDs is that they can be arranged to cover more specific areas. If the application is to disinfect the surface of an 8x11 inch flat area, the directional output of the LED can make better use of UVC power. If compared with the cylindrical output of the lamp in our example, the number of LEDs required may be reduced by 60%. This brings the number of LEDs required to five. In addition, these five LEDs can be arranged in a pattern to provide uniform distribution over the treatment area.


Another factor that affects direct comparison calculations is the way the dosage is used. Lamps usually require a warm-up time until they reach the full output power that needs to be considered when calculating the total dose. The life of the lamp is also greatly affected by the process of turning the lamp on and off. Certain lamp life limits are affected by more than four cycles per day. Even if treatment is not required, the lamp often runs continuously. When directly compared, these will affect the number of LEDs required, the ability to meet lifespan requirements, or overall intensity requirements.


Comprehensive cost

If only the intensity is compared, UVC LEDs may have replaced lamps in most disinfection applications. Although the price of UVC LEDs has dropped significantly in the past few years, it is still important to use the advantages of LED design to build the most efficient system. When designing a system, even if the cost is comparable in some cases, the overall product cost should be considered (rather than relying only on the cost of the bulb or the cost of the LED). Compared with the ballasts required to power the lamps, LED electronics can be smaller, simpler, cheaper and more reliable. By better controlling the UVC LED emission pattern, expensive reflective materials are not always required to take advantage of the lamp's emission UVC pattern.


In conclusion

Compared with lamps, UVC LEDs can provide the same intensity. In general, UVC LED has been able to replace most small and medium-sized applications, and it should be considered for large-scale applications, because the development of UVC LED technology may keep pace with the current product development life cycle. In applications where any type of pulse operation or product needs to be compact, UVC LEDs are the best solution. As products become larger and more powerful, the equivalent intensity calculation between the lamp and the LED or a better LED design solution requires a deeper understanding of all the variables required to upgrade to the new technology To understanding.

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