A HINT OF HIGH TECH

ZEISS VISION CARE – Aalen, Germany

The best perspective in every situation: ZEISS is driving the functionality and quality of glasses to new heights with its innovations. With its coating unit, Bühler is part of this unique development. How will the success story continue? 

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A hint of high tech

The best perspective in every situation: ZEISS is driving the functionality and quality of glasses to new heights with its innovations. With its coating unit, Bühler is part of this unique development. How will the success story continue? 

Victoria Beckham swears by them, and the Spanish athlete Ruth Beitia wore them in Rio 2016 for her Olympic high jump victory: glasses with lenses from ZEISS. If there is one global brand of optics that guarantees the best perspective, it has to be the German manufacturer ZEISS. As Rolex is to watches, Rolls Royce to cars, Apple to phones, and Chanel to perfumes, ZEISS is to lenses. 

Markus Haidl
Markus Haidl is convinced: the glasses success story is not yet over.

And with good reason. The company's history is filled with groundbreaking innovations to this day: as early as the 19th century, ZEISS developed the first physical models for the optical calculation of microscopes. In 1912, the company invented the Punktal spectacle lens, which was the first modern precision spectacle lens ever. The anti-glare coating followed in 1959. In 1986, ZEISS made progressive lenseswith horizontal symmetry easy to wear for the first time. ZEISS has been digitizing optics since 1992, starting with a video-based system for making individual measurements to ensure the lenses fit perfectly. In 2013, ZEISS launched DuraVision Platinum, the most scratch-resistant glass on the market so far. ZEISS also revolutionized customer-specific lens production, so that lenses now need only be processed on the one side – many eyewear manufacturers throughout the world have acquired a license for this technology. Every year, ZEISS invests 10% of its revenue in research and development – which is reflected in the pace of innovation in lenses and optical instruments.

ZEISS plays a huge roll in the successful track record of glasses. Every year, it sells 100 million spectacle lenses in more than 60 countries around the world. There are special designs and coatings for car drivers, people who work with computers and athletes – custom-made lenses optimized for the eyes, face, frame, and lifestyle all bear the ZEISS hallmark. Glasses have since evolved from being a medically prescribed visual aid to becoming an industrial mass-produced fashion staple, an everyday object that sits on your nose and does far more than simply correct vision.

Of course, this makes it easy to forget how important it is to have good vision. “Seeing is believing,” ZEISS researcher Markus Haidl puts it in a nutshell. Education, quality of life, and comfort are unthinkable without clear vision. Seeing is considered to be the most important sense humans have – we take in 80% of all information through our eyes. If your vision is impaired, it is difficult to learn, your working life is drastically shorter, and your quality of life suffers. As in other areas of basic human needs, when it comes to vision, there are still many people who do not have access to optical aids – an estimated 625 million people worldwide.

Blue reflex lens
The blue reflex color of the ZEISS lenses is a unique characteristic made with Bühler coating technology.

Customized mass production

The high-tech nature of glasses is often overlooked. At first glance, a plastic lens just appears to be a transparent piece of plastic. But the ZEISS lenses pack a real punch, in three different ways:

Individual optics: With the ZEISS i.Profiler, the optician can capture the eye's defects with extreme precision – 1,500 measuring points per eye. A special algorithm – known as the Coca-Cola formula of spectacle lens manufacturers – calculates the best possible correction for your vision. Using this as a basis together with your personal visual requirements, it feeds the relevant production parameters for the lens into the processing machine at one of the production sites in America, Europe, or Asia. The result is a truly tailor-made, personalized lens, as unique as a fingerprint. The effect is impressive: "The vision performance in low light conditions and at night is significantly improved. As a result, motorists are safer on the road. Colors appear much more intense – all visual impressions appear sharper and with more contrast," explains ZEISS researcher Haidl.

Production and logistics: ZEISS manufactures up to 15,000 of this type of custom product every day alone in its prescription production facility in Aalen, Germany, and the shaping process is carried out individually for each lens, rather than in batches. Production and logistics run as smoothly as the internal workings of a Swiss watch. Starting from a blank, the glass is shaped completely automatically in around 90 seconds by a five-axis CNC (Computer Numerical Control) processing machine and optically adjusted for its future wearer. The production process from calculating the individual lens to shaping, polishing, tinting, and coating includes more than 30 individual stages in total.

Functionality: "This is where the magic happens, because this is where we differ so much from other manufacturers," explains Haidl. Basic functions such as anti-glare or scratch resistance have long been part of the standard repertoire of glass manufacturers; but now there is a trend toward glasses that are developed for the highest level of comfort and safety in every conceivable situation.

For motorists, for example: The ZEISS developers have created special spectacle lenses that filter out part of the high-energy blue light of modern LED headlights. This part of the light makes the modern lights very bright – good for the driver – but it is irritating for others, for example, for drivers in oncoming traffic. The reduction provided by the ZEISS DriveSafe coating reduces the glare, making it more pleasant to drive at night or in poor visibility conditions. For screen use, for example: the high-resolution retina screens on tablets and smartphones send light waves that signal to our brains that it is day. This affects the distribution of the sleep hormone melatonin. ZEISS lenses can also mitigate the effects of these particular wavelengths. Contact lenses, for example: With EnergizeMe, ZEISS has developed lenses specifically for contact lens wearers. Contact lens wearers also wear glasses for several hours a day to rest their eyes. Given the intensive use of digital devices – which emit a high proportion of blue light – and the particular viewing habits of contact lens wearers, ZEISS offers this target group a product that is optimized for their special vision requirements and digital lifestyle.

Coatings are crucial

This brings us to the subject of coatings: "We use coatings to give the lenses their special functions," Haidl explains. This means that the coating is a crucial process stage in producing the lenses – and also one of Bühler's areas of application.

After an immersion bath for a scratch-resistant coating, the polished spectacle lenses are put in a vacuum chamber, where the layers for the other functions are vapor-deposited. Up to nine individual layers made from six different materials are applied in individual steps. Metal oxides are evaporated in a high vacuum and deposited on the surface of the lens, which is ionized and therefore attracts the oxide molecules with the opposite charge. To also achieve extremely hard and resilient layers, the coating packages are then additionally compressed using ionizing radiation. By the end of the process, all the layers together are only 400 nanometers thick. This is a hint of hightech: this is the distance that grass grows in 15 seconds.

Kark Mati and Markus Haidl working together
Bühler coating specialist Karl Matl and ZEISS researcher Markus Haidl work together to perfect the coating process.

"Compared to these dimensions, in which we have to produce things precisely and reliably, everything else is fairly trivial," says Bühler coating specialist Karl Matl. In case of a potential error, the automated production means that the production process for an individual lens must be started again from scratch. The delivery of the affected customer orders would be delayed by having to produce the lens again, especially if things did not quite go to plan in the coating stage at the end of the process. With several thousand orders a day in Aalen, error-free production is a real challenge.

With the SYRUS coating systems, Bühler Leybold Optics has more or less mastered the art of coating to perfection. It's essential that the high-performance unit does not fail: it must reliably deliver the coating results 24 hours a day, and this is what makes the quality of the ZEISS lenses so unique. The blue reflex color of the ZEISS glasses requires coating thickness accuracy down to the nanometer – these are just a few atom layers on top of each other.

For over 10 years, ZEISS has been so satisfied that Bühler is one of their preferred suppliers and the SYRUS system is used in all of the spectacle lens manufacturer's production sites. "For us, Bühler is not just a supplier, but really a partner," Haidl explains. After all, it is not just the technologies and machines, but ultimately the people who ensure that the research and development work actually ends up on the lens in an efficient industrial process. "And for this, we consider Bühler a reliable partner that shows a great deal of initiative," says Haidl.

Trust on both sides also plays a crucial role here. "We need to ensure that the results we achieve with prototypes can be reliably reproduced in mass production," says Matl. This requires close coordination between ZEISS and Bühler, especially in particular situations. For the transfer of a newly developed, functional coating such as ZEISS DriveSafe, it is also necessary to develop new technologies and coating standards – parts of the innovation process that must be mastered together.

After more than 170 years of ZEISS and over 100 years of precision lenses, one might ask: Is the glasses success story slowly coming to an end? Have developments of the transparent piece of plastic been exhausted?

This question makes ZEISS researcher Haidl and Bühler expert Matl smile. It all comes down to the fact that vision itself is not fully understood. Current brain research allows us to gain deeper and deeper insights into how we humans form a subjective and emotional picture based on a physically objective input of light waves. "The better we understand what's going on in the brain, the better we can construct glasses," explains ZEISS researcher Haidl. At the ZEISS Vision Science Lab in Tübingen, researchers are working on these fundamental questions in close interdisciplinary cooperation with universities and nonuniversity research institutions.

There is also still potential for further optimization in production. "Together, we are working toward being able to control and adapt the coating process more effectively," says Haidl. If that works, it would be possible to work more precisely and eliminate the source of errors more easily. Bühler is currently developing an even more accurate measurement of the nanometer-thin layers in order to achieve greater accuracy for the layer thickness cut-off.

And also in terms of functionality, more riddles need to be deciphered; preventing lenses from fogging up is right at the very top of the list. If antifog glasses were to be launched on the market, it would not just be appreciated by winter sports athletes and chefs. All the renowned eyewear manufacturers are working on it – and it would not be a coincidence if ZEISS, with the close cooperation of Bühler, were to be the first to set a new standard.