UV Light

UV Knowledge
Sentry has mature experiences to provide UV measurement solutions for users with ultraviolet and visible light curing systems. All series of products are designed with a staff of technical specialists available to support our customer’s needs. With high performance, exceptional quality and low cost as primary design considerations, Sentry UV meters are the best values available in the UV measurement industry. Our designs also have proven reliability currently in service around the world.

Sentry UV meters are composed of a number of precision optical elements. The incident radiation passes through an aperture that limits the active area of the system. A diffuser is placed after the aperture and is used to improve the angular response and spatial uniformity of the instrument. An UV filter is employed according to the type UV meter to select the spectral region of the incident optical radiation that strikes the detector.

Introduction of UV
UVA (wavelengths range from 320 to 400 nm) They are only slightly affected by ozone levels. UVA radiation is easily able to reach the earth's surface and can contribute to tanning, skin aging, eye damage, and immune suppression.
UVB (wavelengths ranges from 280 to 320 nm)They are strongly affected by ozone levels. Decreases in stratospheric ozone mean that more UVB radiation can reach the earth's surface, causing sunburns, snow blindness, immune suppression, and a variety of skin problems including skin cancer and premature aging.
UVC (wavelengths range from 100 to 280 nm) They are very strongly affected by ozone levels, so that the levels of UVC radiation reaching the earth's surface are relatively small.

UV Applications
All range of UV radiation can be damaging for human skin. They are also served as special tools of light sources for the industry applications. Many manufacturers establish utilization of UV curing in their manufacturing or laboratory processes.  With the countless possible uses of UV light and curing, the applications are listed below which may be similar to uses you may require in your business: 
  • UV coatings are already widely used for car components, household equipment, various consumer goods and floor coverings.
  • Radiometry and Laboratory measurements
  • UV-curing and printing industry
  • Industrial process monitoring
  • Clinical studies & phototherapy
  • Semiconductor fabrication
  • Environment monitoring
Calibration and Accuracy
An ideal meter would have a well-defined responsivity within a specific spectral region and zero responsivity outside of this region. For example, an ideal UVA meter should have a constant responsivity from 315 to 400 nm and no response outside of this region. To fully understand the accuracy of a UV meter, we must know the optical properties of its components, its spectral responsivity and the relative spectral distribution of the source. The signal i from such a radiometer is the photosensitive area of the meter, A, multiplied by the integral of the product of the instrument responsivity, S(l), and the irradiance distribution of the source, E(λ)

Most UV meters are calibrated at a specific wavelength, and only a nominal wavelength band is specified. In addition, the spectral distribution of the source being measured is often unknown. In practice, most UVA meters still show responsivity outside of this region and might show different responsivity vs. wavelength from other products. Different manufacturers calibrate instruments with measurements of monochrome radiation at a fixed wavelength near 365 nm. Therefore they may show slightly different responsivity for wavelength other than the calibration wavelength.