Ghosts are a lens reflection phenomenon conspicuous in dark areas that are diagonally opposite a strong light. Although coatings were applied to curb reflection, ghost and flare were difficult problems that existing technology had been unable to eliminate completely. The surfaces of standard coated lenses appear green or blue. This is due to the wavelength characteristics of the coating, which reflects various green and blue light wavelengths—or in other words, retains the wavelengths for those colors. The most difficult proposition is to prevent the reflection of light that enters the lens diagonally. Although existing coatings have been effective to a certain extent with light that comes in perpendicular to the lens, they have typically been very poor at coping with light with a large angle of incidence (that is, their angular characteristics were unsatisfactory). If you incline the lens as far as you can and look at it diagonally, you can see that it still reflects light like an ordinary sheet of glass. By comparing the samples here, you will probably be able to see clearly that the one with the Nano Crystal Coat applied to it does not look as if it consists of 14 sheets of glass. Although 14 sheets of glass amount to a total of 28 reflective surfaces, the reflection hardly changes at all—even when the lens is inclined.
It's plain to see, isn't it? With its transparent feel, the one with the Nano Crystal Coat is completely different.
People often say “Did you forget to put a lens inside?” There are three main properties required of a non reflective film. The first is to reduce the reflection within the lens of light with a perpendicular incidence; the second is the ability to curb reflection over a wide range of wavelengths; and the third (which is regarded as the hardest) is to effectively prevent reflection, even when the light has a large angle of incidence. The Nano Crystal Coat is a revolutionary coating that can offer improvement in all three areas-the perpendicular incidence characteristic, the wavelength characteristic, and the angular characteristic.
I'm interested in the moment at which this remarkable technology was conceived. What was the original impetus for its development?
A stepper consists of photolithographic equipment for reducing an original master circuit design diagram using lenses, and transcribing the design onto silicon wafer. This ultra high precision machinery has been dubbed “the most precise equipment ever,” and since developing the first domestically manufactured stepper in 1980, Nikon has been ahead of other companies in building original technology, of which the Nano Crystal Coat is one example. At the turn of the millennium, as semiconductors became ultra miniaturized and ultra detailed, the projection lens of the stepper was also required to be of extremely high resolution. As the number of lenses and the aperture were increased in order to improve the resolution, the barrel housing the lens grew to approximately 1 ton in weight and as much as 1 meter in height. With such large lenses, the angular incidence of light in the periphery of the lenses was extremely large, making it difficult to prevent reflection. Large hemispherical lenses resembling a fortune teller's crystal ball were also used; however, it was particularly difficult to form the coating, which was intended to increase the transmittance onto such rounded lenses, making it impossible to manufacture a coat with the desired capabilities using conventional methods; thus, success was virtually impossible.