Mar 19 2007
Firstsight Vision now offers the new range of UV and IR LED illumination sources from CCS. UV and IR lighting provide powerful alternative illumination possibilities for applications where visible light illumination is inadequate. Experts from Firstsight Vision can ensure optimum results are obtained using these light sources, by recommending the appropriate optical systems and cameras for use with them. Most CCD cameras are not very sensitive in the near-ultraviolet region, so for UV applications, it is essential that a suitable camera is selected. UV filters may be required and it is important to take into account their effects on the overall imaging conditions.
The IR range is available in 32 models, offering different illumination geometries for different applications. These include high density ring lights, power-saving back lights and high intensity LED arrays. A choice of two different peak wavelengths of 850 nm and 940 nm can be selected according to the object to be inspected, since the images taken may be affected by the emission spectrum distribution of the infrared LED used and the spectral sensitivity characteristic of the CCD camera. The LED directional characteristic can be selected between 15˚ for direct light types and 30˚ for plane emission types as standard models.
The long wavelength of IR light compared to visible light generally results in less surface scattering and greater transmission. High transmission can make IR ideal for inspecting package fill levels or detecting the presence of foreign matter. Lower surface scattering means that IR light can provide clear inspection of surface details such as scratches, chips, holes, edges or characters on a wide variety of materials including paper, cloth, plastics and metals, even if they are covered with print or paint.
The UV LEDs are available in 31 different models and have a peak wavelength of 365 nm and a light spread of 20˚ for good intensity, range and uniformity. The range is characterized by a unique structure which protects against sparks caused by static electricity. This prevents illumination failure due to sparks caused by contact with a piece of metal, etc., resulting in significantly improved safety and reliability.
UV light is most commonly used to make materials such as inks or glues fluoresce for identification or bonding integrity inspection.
It also scatters off very small surface features such as scratches more readily than longer wavelengths.