Borescope

The heart of a borescope design is the relay lens system. Borescope lens are available in several types:

-Achromatic - mostly used medium to large diameter borescopes. Features good color correction, but is limitted in diameter - nearly 5mm

-Gradient Index - it implies a relatively new technology in which the index of refraction profile from center to edge of the relay is precisely controlled during manufacture instead of grinding, polishing, coating and cementing individual lens elements to form a relay. Used in small to medium diameter scopes, providing very high image quality using a simpler design

-Fused Quartz - fused quartz relays find application in very small diameter medical endoscopes or industrial borescopes. Flexibility is limted

-Rod Lens - the rod lens relays were invented by H. Hopkins and provide brighter images for a given diameter. Rod lens provide wide field or view combined with very good color correction and image quality.

Gradient Lens Corporation is one of the leading brands for producing borescope lens. They have teamed up with Hawkeye in the production of Precision Borescopes. Their lens offer superb image quality and a broad range of features and applications.

In the design of the first borescopes featured a series of lens pairs that form and reform images, each image the subject for the next relay set. The spacing between series is proportional to the diameter of the lenses, so this color-corrected design works quite well for larger diameter borescopes. They had poor image quality because of the fact that too many lenses had to be positioned too close together.

Hopkins was the one to improve that when he patented a new design in 1966. He combined conventional lenses with short, optical-glass rods to give higher brightness, accentuated color, higher contrast, and sharper images when compared to the achromatic doublet relay of the same diameter.

The latest technology is applied in the endoGRINS� gradient index lenses, by Gradient Lens Corporation in partnership with Hawkey. This technology is utilized in the Hawkeye Precision Borescope. EndoGRINS lenses are longer optical glass rods treated in an ion exchange process. This results in large cost savings, because it is totally different than the expensive micro-lenses which had to be ground, polished, coated.

Lenox Instrument is a U.S. manufacturer that has been producing borescopes since 1920. The interesting about them is that they are the only company that has an in-house lens production facility so they produce their own borescopes lenses. This allows them to achieve greater control and maintain the highest quality optics to make sure the customer gets the brightest, clearest, true-color images.

Upper Endoscopy | Borescope Lens | Camera Lens | Gradient Lens | Optical Lens | Rod Lens |