Vision:

Vision is far more than just creating a spectacle lens. Lens materials are key components of the innovation process, achieving solutions that satisfy and anticipate needs and aspirations.

There is a great variety of lens materials available in the world today. However, sometimes quality leaves much to be desired. Disadvantages of cheap or low-quality materials may not be visible at first sight, but they will seriously affect visual quality, comfort and lens appearance.

Hoya always focuses on product development that meets the requirements of today's and the next generation of consumers, and pays attention to optical, cosmetic and physical lens performance.

The basic elements: monomers selection:

The decisive factors for the best optical performance are the monomers selected and the way they are processed. Before developing a new material group for plastic lenses we focus on basic elements: the monomers, their molecular structure and lens material formulation.

Hoya selects "high optical grade monomers from the chemical industry. Specific monomers and so-called 'cross-linkers" are used for developing new materials, meeting new challenges and aiming for better output. Mixing specific monomers yields new plastic materials, with unique characteristics: for example, as regards resistance, safety and, above all, optical and cosmetic performance.

Physical performance & temperature sensitivity:

Individual physical characteristic are critical factors for achieving high-quality end result referring temperature fluctuations. Cheap and wrongly selected materials are very temperature-sensitive. That means, they are only resistant up to a certain temperature. Above this temperature, surface accuracy & consistency can no longer be guaranteed and surface deformation may occur.
The problem primarily arises during finishing procedures, which take place immediately after production.

Process improvement:

The first finishing procedure is colouring the lens ....... applied temperature: 90-100 degrees Celsius during 10-30 minutes.
The next attack on the heat resistance tolerance limits comes with the addition of the hard layer, critical during the hard coat curing procedure. Again, the lens is exposed to a temperature of 120 degrees.
Last but not least, there is the vacuum coating evaporating procedure, providing the lenses with antireflection layers, when the spectacle lens must be once again be resistant to temperatures of up to 100 degrees.
If heat resistance is low and a certain temperature is exceeded, one can imagine the deformation of the lens surface, starting from the centre of the lens and visible as a "wavy' effect.

Special attention to this 'wavy' surface effect and its consequences in daily practice is of crucial importance when selecting the spectacle lens material, because it is difficult to detect with the naked eye.

Temperature fluctuations in daily life:

Have you ever visited a sauna right after skiing? An excellent opportunity to measure the temperature sensitivity and stability of lens material and the treatment it has undergone.
Another example is that of rapid readjustment of the frame in the frame warmer, where it becomes subject to excessively high temperatures.
Disregard for maximum tolerance and for stress differences between material and treatment greatly increase the chances of damaging the lens surface .
The result: visible hairline fractures in the AR coating layer, also known as craquelé. And what's more: complaints from your customers.

Chromatic aberration:

Another critical aspect is chromatic aberration, better known as 'colour dispersion'. Although not visible at first sight, chromatic aberration can, for instance, have a major negative effect on contrast vision and visual acuity, especially if the Abide value is low. According to Hoya, the Abbe value should be 36 at the very lowest. Unfortunately, not a few so-called "added-value" or "high-end" materials available in the world today have Abbe values below 36.

This factor is intensified by continuously changing visual orientation. It can be particularly disturbing in a change of the direction of the eye and, because of the different positions of the colour focal points, it can be caused by chromatic aberration.

Interference patterns:

Another prominent and visible shortcoming in critical quality plastic lenses occurs when manufacturers provide the lens with a hard layer and/or multi-layer antireflection coating, with indexes different from that of the lens substrate.

UV absorption & Transparency:

At present, a UV-absorbing plastic lens is popular and also more effective. This is a unique selling point, now that UV sensitivity is gaining in importance, in view of damage to the ozone layer and the increase of the average life expectancy.

Addition of UV-absorbing materials to the chemical composition of the lens gives it yellowish colour, whereas clear lenses are popular.

To neutralise the yellow hue, a blue colouring agent must also be added. This, however, results in considerable reduction of the light transmission value and hence of lens transparency, despite its high-quality multi-coat anti-reflection layer.

HOYA

Substrate Matching Process concept & process improvement:

To assure the highest possible quality HOYA employs remarkable and sophisticated combined technology: the Substrate Matching Process concept. One of its key technological experiences is the index-matching hard coating. That means, for substrate index 1.5, 1.6 or 1.7, with the same specifications for the hard layer index.
And, in order to complete this balanced process, based on the same philosophy, the multi-coat antireflection layer indexes are in perfect harmony with the basis substrate and hard layer index specifications.
If this highly balanced technology is not applied, or the requested index matching philosophy is misapplied--for example with relation to 1.5, 1,6 or 1.7 index plastics--the incorrectly applied hard coating liquid 'alternatives' result in so-called 'Newton rings', caused by interference patterns, negatively affecting the appearance of the lens.

The results of Hoya's efforts and know-how:

In recent years, guided by its aims, know-how and long-term technological experience, Hoya has developed a number of high-quality plastic materials and treatments, with a number of striking and practical characteristics, based on Hoya standards. Safety, reliability, durability, scratch resistance, elasticity, UV-protection and transparency are key element for reflecting Hoya's differentiating quality aspects and advantages.

These standards are based on:

• Tradition
• Know-how
• Technology
• Innovation
• They have the following advantages:
• Quality guarantees
• Top results
• Optimisation of vision quality
• Profit from the latest innovations