UV is an electromagnetic wave of 100 to 380nm wavelength, longer than that of X-rays but shorter than that of visible rays.
UV is classified into three categories shown below according to its wavelength:
When UV is used to cure the resin, the following units are used to measure the amount of UV radiation:
– Irradiation intensity (mW/cm2)
Irradiation intensity per unit area
– UV exposure (mJ/ cm2)
Irradiation energy per unit area and total quantity of photons to reach the surface. Product of irradiation intensity and time.
– Relationship between UV exposure and irradiation intensity
E=I x T
E=UV exposure (mJ/cm2)
I =Intensity (mW/cm2)
T=Irradiation time (s)
Since UV exposure required for curing depends on the material, the required irradiation time can be obtained by using the above formula if you know the UV irradiation intensity.