STORIES

The safety of the water we use is ensured with optical materials

Nikon helps contribute to the alleviation of worldwide concerns with advanced optical materials.

4D Free-form SG (Silica Glass) can be designed flexibly and allows UV light to pass through. It is expected to be utilized in wide-ranging fields including sterilization UV-LEDs for water treatment.

A world water crisis that is becoming more severe

Water is indispensable for all our lives. However, 2,100 million people (approximately three out of ten people) have no access to safe water around the world currently. 159 million people among them drink unprocessed water taken directly from rivers or lakes.*1

Water treatment to render water drinkable generally utilizes chlorine for sterilization. However, with this method, there are risks that some bacteria might develop resistance to such purification chemicals.

Given the circumstances, UV light with an approximately 254nm wavelength (UV-C) is expected to be an effective sterilizing method, and UV-light emitting diodes (UV-LED) are attracting attention as the light source. 4D Free-form SG (Silica Glass), created employing a new method, is contributing to this advance.

  • *1 Reference: UNICEF and WHO joint inspection program report, “Progress on Drinking Water, Sanitation and Hygiene: 2017 Update and Sustainable Development Goal Baselines”

New silica glass that Nikon’s unique processing method produces

Optical materials that can transmit UV-C include silica glass and calcium fluoride. In particular, Nikon’s silica glass contains hardly any impurities, so it realizes superior transmittance. Because it has very few impurities, its melting point is high which provides an excellent advantage regarding heat and chemical resistance and can therefore be utilized in severe environments. Thus, it is an essential optical material for optical systems such as semiconductor lithography systems and FPD lithography systems.

The greatest feature of 4D Free-form SG (Silica Glass) is its free-form characteristics while taking advantage of these silica glass benefits. Nikon has developed a new method that can form a complex design in a single process, which significantly improved the flexibility of the optical design. To represent this, the 4D of the product name means that an extra “D” (optical design) is added to “3D” (three dimensional form).

Because of these characteristics, 4D Free-form SG (Silica Glass) is expected to be developed and applied in fields that require transmittance and heat-resistance performance, such as UV-LEDs for sterilizing water and air, and LEDs for vehicles.

A silica glass ingot is formed by depositing gasified materials in an ultrahigh-temperature furnace. The temperature at the center of an ingot reaches approximately 2,000˚C (approximately 3,600˚F).
A completed silica glass ingot. Projection lenses for semiconductor lithography systems, for example, are made from it by cutting and grinding.

Unique optical materials produced from an integrated manufacturing system

Extremely hard synthetic sapphire can be processed by micromachining and precision parts can also be manufactured. The image shows a gear of a wristwatch mechanism (diameter 3 x 3 mm/0.1 x 0.1 inch)

Nikon started researching optical glass manufacturing in 1918, the year after its establishment, and currently produces high-quality optical materials and FPD photomask substrates consistently, from melting materials to processing. What’s more, various kinds of precision equipment employing such optical materials are also manufactured. Nikon is a rare company that produces all of the materials, handles the entire processing operation and then applies them for use with precision equipment.

Nikon manufactures a range of optical materials other than silica glass. Synthetic sapphire optics is an example. Sapphire is hard, next to diamond, and difficult to process, but Nikon has developed a micromachining-processing method. Small, high-precision parts such as the gears of wristwatch mechanisms can be made. It is also suitable for areas requiring strength such as smart device protection glass, camera lenses exposed on the outside of a vehicle, the cover glass for an endoscope distal end section that is sterilized by heat and chemicals, or optical components for lasers that must tolerate extreme heat.

What’s more, Nikon supports a wide range of cutting-edge manufacturing techniques with various optical materials such as calcium fluoride that realizes an optical system with very few chromatic aberrations and is utilized in semiconductor systems, and the ceramic coating that protects carrying rollers.

Supporting epoch-making solutions with advanced materials

Glass Business Unit
Tomohisa Komiya

Developing 4D Free-form SG (Silica Glass) required extensive knowledge of wide-ranging fields including the optical and mechanical processing areas, as well as chemicals. Nikon is both an optical manufacturer and precision instrument manufacturer, so benefits from having skilled professionals in various fields. With their expertise, Nikon has practicalized extremely useful optical materials.

Currently, cameras are being installed on many vehicles. Image recording devices are becoming diversified and increasing in number, while the optical material characteristics demanded are highly diversified. We would like to fulfill the needs of society more rapidly and provide optimal solutions as fast as we possibly can.

Glass Business Unit
Yu Okuyama

Synthetic sapphire requires crystals to form slowly, taking considerable time, so temperature control was extremely difficult. Repeating the process by trial and error, I could not have been happier when it finally succeeded.

Utilizing the optical materials that we produce so painstakingly for Nikon products such as lenses and prisms, as well as many other products, is very satisfying and worthwhile for us.

The advanced materials we create often drastically improve equipment performance. We would like our optical materials to produce solutions that lead to greater innovations, thereby revitalizing industries throughout the world.