The weekly report summarizes progress of the Habithai multidisciplinary workshop group. The engineering team members are working on ultraviolet LED design. Ultraviolet LEDs above 365 nm have higher efficiency around 20% and stronger power output than lower wavelengths. These LEDs are beginning to be used in UV curing applications. The strong point of UV LEDs is cleaning bacteria in water and food, while the weak point is they can burn human skin if receiving too much high energy. Next week, the engineering students will design circuits after the product design team chooses a project concept.

1. [INC 281 MULTIDISCIPLINARY WORKSHOP WEEKLY REPORT] March 7, 2012
Name-Surname Pongsakorn Srirattanapiwat
Student ID. 53211839
Group Name Habithai
Engineering Team
U,Boon,Gang,O,Tob,Toss
Members
Product Design
Pete,ice
Team Members
Weekly Progress
Ultraviolet LEDs can be manufactured to emit light in the ultraviolet range, although
practical LED arrays are very limited below 365 nm. LED efficiency at 365 nm is about 5-8%,
whereas efficiency at 395 nm is closer to 20%, and power outputs at these longer UV
wavelengths are also better. Such LED arrays are beginning to be used for UV curing
applications, and are already successful in digital print applications and inert UV curing
environments. Power densities approaching 3,000 mW/cm2 (30 kW/m2) are now possible, and
this, coupled with recent developments by photo initiator and resin formulators, makes the
expansion of LED-cured UV materials likely.
Figure 1. Figure 2.
Engineering Analysis
Strong Point
- clean bacteria in the water, food
Week Point
- High energy some type when receive more might make skin of human burn.
Next Week Job
- At the moment , Id students thought many projects. I will try to tell them to choose only
one . After that, engineering students can do the job that is design circuit.
Department of Control System and Instrumentation Engineering
KING MONGKUT’s UNIVERSITY OF TECHNOLOGY THONBURI