Back-illuminated CCDs offer UV imaging

Designers wanting to image in the ultraviolet (UV) typically use either photodiode arrays or image-intensifier tubes. But photodiode arrays are noisier than CCDs, and their quantum efficiency is low. Image intensifiers, on the other hand, are expensive and have relatively poor resolution and contrast.

Sep 1st, 1996

Back-illuminated CCDs offer UV imaging

Designers wanting to image in the ultraviolet (UV) typically use either photodiode arrays or image-intensifier tubes. But photodiode arrays are noisier than CCDs, and their quantum efficiency is low. Image intensifiers, on the other hand, are expensive and have relatively poor resolution and contrast.

To meet the needs of spectroscopists, camera manufacturers have used down-converting coatings to allow front-illuminated CCDs to image in the UV range. According to George Williams, vice president and general manager of PixelVision (Beaverton, OR), the problem with such coatings is that they have to be replaced periodically and are neither stable nor efficient.

PixelVision has developed a 1100 ¥ 165-element back-illuminated CCD camera, the SV165, designed to replace front-illuminated CCD-based cameras in applications such as astronomy, UV microscopy, and Raman spectroscopy. The 16-bit/pixel resolution camera offers greater than 40% quantum efficiency over the entire UV and visible spectrum.

The SV165 has a CCD especially designed for PixelVision by Scientific Imaging Technologies (Beaverton, OR) and a two-stage Peltier device to cool the CCD sensor to 65 below ambient temperature. For ease of systems integration, the camera is supplied with a PCMCIA, ISA, or PCI interface card and PixelVision`s PixelView, a Microsoft Windows-based application package.

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