UVC and LED things to consider

During some research on portable UVC-LED germicidal lamp, it was interesting to know if it is possible to increase the power of existing germicidal lamp with 8 pcs UVC beads from 2.40w to 3.60w? Since Covid-19 needs a high dose of UVC.

Here is some technical information about the UVC-LED beads below:

Voltage difference between regular lighting-purpose beads and germicidal UVC-LED beads

Type Standard Voltage In Theory Practical Voltage In Production

UVC Beads 6-6.5V 6-9V

1. The characteristics of UVC beads

1) The voltage standard of UVC beads in theory shall be among on 6.0-6.5V and the working efficiency is very low with about only 3% for germicidal function while other 97% for producing heat so that the working temperature could be pretty high. The standard is so strict that even big brand UVC beads suppliers all over the world only has 10% finished beads can fully meet even for. The loss and cost are too high to accept which finally make actual standard with existing technology relax to 6-9V. Even though, only about 40% is truly acceptable.

2) The rated current of UVC-LED beads is 60mA, which designed based on 6V, the standard voltage in theory. However, when some of the beads which voltage probably reaching 9V, the limit current for safely long-term using would have to reduce to 40mA only, otherwise the exceeding power causes severe overheating and finally make the life span of the UVC bead decline rapidly. After fully evaluating and tests, we found it is available to make the whole circuit working steadily on 2.7w with existing 8 beads. Considering safety, life span and quality of item, we can not increase power to 3.6w with limited rated current 60mA.

2. The fact and explanation for percent of pass in UVC bead production & chip packaging and market flowing

1) The UVC chips

i. Even with standard with 6-9V, only about 40% finished chips can truly reach the standard, others will be poor products and not acceptable for QC department.

ii. The remaining 60% chips which unable to pass the voltage standard will be acquired by some people or merchants and finally sold to those UVC chip packaging enterprises that do not have enough budget or source to purchase qualified beads from market.

iii. The price of those unqualified UVC chips are pretty cheap, while the standardization and consistency of products, or life span are unwarranted.

2) The chip packaging

i. When the chip packaging factories get the UVC chips, the effective percent of pass for packaging is only about 80% and still have 20% unqualified products. Therefore, you can see the real qualified beads and chips are definitely rare with almost 32% success rate from beads production to chip packaging, which explaining that why the price of qualified bead is extremely high. We only use qualified UVC beads made by big brand suppliers for our germicidal lamp and can not accept the unqualified material.

ii. However, the 20% unqualified chips will be still delivered to downstream just as unqualified beads, and finally sold on the market for germicidal products unfortunately.

3. The total power

Most chip suppliers are offering is 275nm due to technical and commercial consideration. In terms of UVC LED radiation power alone with other factors, 12W (wich is the UVC radiation of T8-36W) is like needing 1143pcs 10.5mW (type PB2D-1CLA-TC) LED.

Conclusion :

1.you need a lot of LED chips to have same effect as T8. Technically you will have a lot of issues in developping. There is also the QC to use only the best chips.

2.a lot of bad UVC chips will fload the market