Takahashi Laboratory
A factory at your fingertips - The light revolution

Smartphones can be used for almost everything. Fitness watches acquire health data. IT-equipped automobiles can drive themselves. Everyday objects are growing smarter and smaller, but what about the factories which manufacture products? Takahashi Laboratory, which focuses on advanced manufacturing using light, engages in research into extremely tiny factories which create devices so small they cannot be held. Let's learn more.

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• A gingko tree leaf, the University of Tokyo's symbol, created using evanescent light.
   It is a single manufactured piece, just 100nm thick, on a field measuring 100μmx100μm
  (created by Mr.Suzuki of the Takahashi Laboratory)

Vision is one of the most important senses because of the sheer amount of information it provides. Vision is made possible by light, which Professor Takahashi declares is a tool. The light that we normally see is either given off by objects, or reflected and scattered by objects, passing through space to reach us. In other words, the light we normally use is always propagated. Evanescent light, however, is the small amount of light that penetrates the material with the lower refractive index when light strikes materials with different refractive indices at a specific angle and undergoes total internal reflection, without losing any information. Takahashi Laboratory, focusing on the fact that this light is not propagated through space, and penetrates to a depth of only around 100nm, began researching techniques for applying evanescent light to stereolithography.

"Based on the fact that information is retained because the light is not propagated, and that the layer is extremely thin, our goal is to develop 3D printers with a printing layer thickness on the order of 100nm. Objects are made, not by scanning 'points', but by simultaneously printing 'areas', so this would make it possible to create special objects such as thin, flat panels with complex micro-functional structures," says Professor Takahashi.

If this technique were used in microprocessing the surfaces of photovoltaic panels, it could contribute to reducing the amount of light reflection and improving light collection rates. "Conventional devices have a single layer thickness of around 5μm. This is equivalent to fifty 100nm layers made using evanescent light. Evanescent light could be used for even higher precision manufacturing."

So far, the laboratory has succeeded at creating objects made up of ten layers, each several hundred nm thick. There are still challenges with lamination stability, but Professor Takahashi feels confident, saying "Evanescent light carries highly detailed information, so it was originally used for measurement. Because that energy is localized, it can, of course, also be used for processing. When the idea of stereolithography was first developed, it took an extremely long time just to harden resin using evanescent light. Honestly, at first I thought that we had reached the limits of what was possible, but my students worked hard, and we overcame that hurdle. We're now seeing all kinds of possibilities which at first we didn't even imagine. It's important to persevere in one's research (laughs)."

When we can see things which we have never been able to see before, and create things we have never been able to create before, cell-in-micro-factories will integrate these optical manufacturing technologies. These factories, smaller by far than anything that has come before, are Professor Takahashi's own original idea. The smallest factories which exist today are "desktop micro-factories," which consist of machine tools such as micro-lathes. Cell-in-micro-factories, measuring just several dozen millimeters wide by several millimeters deep, are to contain the most advanced optical technologies, performing everything from measurement, processing, and handling to conveyance and defect detection. The objects they manufacture will measure less than 1 millimeter. When asked where his creativity springs from, Professor Takahashi answers, "I come from Kansai, so I love comedy. Comedy consists of gaps, right? I think research works the same way. You need surprising gaps, where people think you're going to go one way, but then you come at them out of left field. I often send myself emails with ideas I think up in the morning, when I'm still kind of out of it."

Professor Takahashi continues, in Osaka dialect, "My research is application oriented, thinking about factories and manufacturing, but I also want to work with light. Light is a really fundamental energy. The reason why life arose on earth and why we have petroleum is the light provided by the sun long, long ago. We're all benefitting from that. There are a lot of aspects of light that science still needs to explore. What's interesting about our research is that we study light, but we also work on practical applications." Professor Takahashi talked enthusiastically about his research, but said lately there's been something that has worried him.

"In my lectures...my jokes always go over like lead balloons. There are just these dead silences."

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• Micro-miniaturization leads to ultra energy saving. The future of manufacturing, overturning the conventional factory concept.