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The one-billion-dollar lens

It all started with a simple lens for overhead projectors. Today, microreplication has grown into a billion-dollar business. The broad-range product family covers light-guiding films and abrasives as well as fastening systems.

What does "microreplication" actually mean?

How it all started - a kind of evolution

3M researchers "play tricks" on the laws of nature

Small cause - big effect: a new technology forms the base for many useful products

What does "microreplication" actually mean?

Mircroreplication means that:
an existing 3D micro structure can be repeated continuously a million times.
The structures are pyramids, cube corners, balls or edges that are invisible to the naked eye since they are in the millimetre, micrometre and even nanometre (a millionth of a millimetre) range.
It was only by and by that 3M researchers discovered the enormous new product potential provided by the development of microstructured surfaces.

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How it all started - a kind of evolution It all started when researchers wanted to launch a low-cost, lightweight overhead projector in the 1960s. Roger Appeldorn, today known as the father of microreplication technology, discovered that the Fresnel lens (pronounced "frenell"), which had been used to focusing lights for decades, was useful for that purpose. In contrast to a thick glass lens, the Fresnel lens is a flat plastic lens which uses thousands of small grooves to achieve the same light-bending effect as traditional lenses. If equip a surface with tiny, V-formed grooves, as they are used in the Fresnel lens, not in circular but linear form and in two or three directions instead of only one, you receive thousands and even millions of uniform edges, pyramids or cube corners with certain optical or mechanical properties depending on the material. 3M's Traffic Controls Division, one of whose key products are reflective sheeting used in road traffic signs, soon identified interesting applications for the new technology. Research efforts along with optics research on cube corners started in the early '70s and soon formed the foundation for a very successful product: Scotchlite™ Diamond Grade - a reflective plastic sheeting - is substantially brighter than conventional reflective materials. Motorists can see signs equipped with this sheeting at great distances day and night and can thus react more quickly - a major advantage with regard to traffic safety.

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3M researchers "play tricks" on the laws of nature An indisputable 'star' among microreplication products is 3M ™ Brightness Enhancement Film. The product which, along with 3M ™ Optical Lighting Film and 3M ™ Lighted Guidance Tubes, belongs to the family of light guiding films, is something of a physical "miracle". If you place the sheeting before a diffused source of light, it seems brighter than without this filter when looked at it vertically. However, optics teaches that a light source always loses brightness when a filter is placed in front of it since the filter "swallows" part of the light energy. Sophisticated caculations with hyper-modern computers showed that the sheeting's microstructure lets only those light beams pass that come in vertically, yet reflects those that come in at an angle to and fro till they also hit the sheeting vertically. This enforces the effect of the vertical beams. For the observer, the light seems brighter when viewed vertically. When viewed from the side, nothing can be seen.

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Small cause - big effect: a new technology forms the basis of many useful products Today, nearly all laptop computers use microreplication technology. The film's light-enhancing effect results in energy savings of approx. 20 to 30%. This means that the operational time of these devices is increased from three hours to four hours at the same battery performance. This removes the need for a more expensive and bigger and - particulary undesired for laptops - heavier battery. An unbeatable efficiency argument for laptop manufacturers and users. Enormous energy savings through focused light guidance can be achieved in many areas. Light guiding films can pump artificial light or even daylight everywhere where light is at a premium, for example from the rooftop to the interior of a building or from the entrance of a tunnel into the tunnel itself. Researchers estimate that daylighting panels which redirect natural light into buildings could help to save up to 30% of energy. This technology is also useful in farming, e.g. to provide sufficient light in greenhouses. Another application is the innovative and rather succsseful 3M™ Precise Mousing Surface mouse pad. It enables accurate and effective PC mouse control. Microreplication has not reinvented the wheel but for that the abrasive. Our Structured Abrasives feature an engineered surface of microscopic oxide grains resembling pyramids embedded into flexible fabric substrates. These new abrasives are particularly well-suited for high-performance sanding jobs. They achieve finest finish on ultra-hard, high-alloy materials such as stainless steel, chromium, nickel and titanium. They also enable superior sanding results on surgical instruments, artificial joints, jet blades, golf clubs and other high-quality materials.

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