Why does UV LED emit blue or violet light?
Many people are very curious, isn't ultraviolet light invisible light? How can the UVLED curing light still see purple light or blue light when it is operating? Is there a problem with the device? Here we will talk to you about visible light and invisible light. The visible light that ordinary people's eyes can perceive has a wavelength between 780 and 400 nm. If it exceeds the range, it is invisible light. In general, invisible light will not cause people's visual response, that is, invisible.
So it stands to reason that the uvled curing lamp emits ultraviolet light, which should be invisible light, so why can we see visible purple light or blue light when using uvled lamps?
The main reason is that ultraviolet light is actually light in the ultraviolet spectral range emitted by the excitation and recombination of electrons and holes in UVLEDs. While emitting ultraviolet light, there is also visible light in the adjacent band, so in addition to ultraviolet light, visible violet light and blue light can also be seen. , so the UVLED curing lamp can see violet or blue light.
Moreover, the light emitted can remind people that they are under the irradiation of ultraviolet light. If there is no special need, do not stay for a long time, because the ultraviolet light emitted by UVLED belongs to the UVA band, which is 320~420nm, because its wavelength is longer. , can penetrate the skin surface and cause harm to the human body.
Ultraviolet light is invisible light, and ultraviolet light can see violet light because a photoinitiator (or photosensitizer) is added to a specially formulated resin. After absorbing high-intensity ultraviolet light in an ultraviolet (UV) light curing device, active free radicals are generated. or ionic groups, thereby initiating polymerization, cross-linking and grafting reactions.
Converts resins (UV coatings, inks, adhesives, etc.) from liquid to solid in seconds (varies). (This change process is called "UV curing"). The physical properties of UV light radiation are similar to visible light, and they are linear, but their penetrating power is far less than that of visible light. Good inner layer curing.
