With the development of mobile computing, the demand for low weight and high rigidity notebook PCs has risen extremely high. At the Lenovo Japan Yamato Off ce, the location where ThinkPad computers are researched and developed (Yamato City, Kanagawa Prefecture), we are striving to stay in the lead in answering the demands of this era. In response we are pursuing the development of materials that achieve low weight and high rigidity and tougher case structures. In this issue we will introduce two of our masters of design working on the case design for ThinkPad.

(Interviewed September 10, 2010)

—What are the characteristics of CFRP (Carbon Fiber Reinforced Plastic), the material that has been used in ThinkPad cases since the first-generation ThinkPad 700/750 Series?

Mizoguchi: It is low weight and highly rigid. It has excellent impact absorption. By changing the types of carbon fibers or their combination,

a completely new material is born so they are highly flexible. Because it is difficult to manufacture them, however, the number of suppliers is limited and this results in high costs.

Ohtani: In the 1990s, we were using resins to make cases with a thickness of 1 to 2 mm because we still could not mold thin pieces of magnesium alloy. At that time, this resulted in very high costs and in order to achieve low weight and high strength as well as reliability, we had to accept the issue of cost and adopted CFRP.

Mizoguchi: Even so, the first few generations of CFRP had a variety of issues in the areas of mass production

and external appearance, etc. From that point onwards, we worked to make improvements by adjusting the blends of the fibers used and the length of the fibers (Figure 1). Also, at that time it was used as a molded material, but now we use it as a plate material with extremely high strength. From the ThinkPad Z Series onwards, we began using a hybrid material with a sandwich structure in which a foam material was pressed between carbon fiber sheets. This brought the specific gravity below 1.0 and we achieved a low enough weight that it would float in water.

Manager, Senior R&D Engineer Platform Mechanical Design, Subsystems, Notebook Development Lab. Lenovo Japan Ltd.

Tetsuya Ohtani

Achieving both low weight and strength: Continuing progress with CFRP

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The Masters of ThinkPad Development

Ohtani: The floating up of the carbon fibers in CFRP results in an uneven product surface. We have repeatedly made improvements in this area to the materials, manufacturing method and surface treatment.

— What was d i f f icu l t about developing these materials?

Ohtani: Instead of having the materials and making a product, the development of both of these occurs simultaneously. If both of these areas are not addressed at the same time, we will be slow to respond to changes in the market. Evaluating new materials and applying them to the product continues on a tight schedule right up until before the product enters mass production.

—What has been the key strength for Lenovo, which has been able to develop epoch making materials ahead of its time?

Ohtani: I would say that has to be

the material manufacturers that are our partners. Japanese carbon fiber manufacturers are some of the best on the planet. This offers us the significant advantage of being able to use new materials ahead of the rest of the world. I think Lenovo might be the only company, even amongst Japanese PC manufacturers, that is in close communication with partner companies and constantly incorporating new industry trends in its materials development.

A tough frame protecting internal parts, the “ThinkPad Roll Cage”

— Next, I would l ike to ask about the ThinkPad Roll Cage that is being used in the ThinkPad T Series and R Series. I have heard that this integrated frame made of magnesium alloy was a major breakthrough in terms of progress from previous frames.

Mizoguchi: I think it is a major innovation. The amount of flexing

that occurs when you pick up the case in one hand is completely different. If you pick up a computer in your hand and compare them, the difference with previous frames is obvious. In previous frames, magnesium was being used in some areas and was being reinforced here and there using stainless steel or aluminum plates.

The R Series is no longer for sale.

The case of the ThinkPad T410s achieves a specific gravity of 1.0 or less by using a sandwich structure in which a core of foam board is sandwiched by CFRP.

The struggle for low weight and high rigidity at the cutting edge of case design

Staff R&D Engineer Platform Mechanical Design, Subsystems, Notebook Development Lab. Lenovo Japan Ltd.

Fumitake Mizoguchi

Figure 1: The history of the progress of ThinkPad and CFRP

First Generation (1992 X -)ThinkPad 700/750 SeriesThermoset CFPR used. After satisfying the strict standards of NASA, the ThinkPad 750 was the first to go to space in the space shuttle.

Second Generation (1996 -) X

ThinkPad 560/570 SeriesChanged to the manufacturing technique used for ordinary plastics of injecting melted CFRP into metal molds.

Third Generation (1998 -) X

ThinkPad 600 SeriesThe amount of carbon contents increased while retaining manufacturability.

Fourth Generation (2000 -) X

ThinkPad T20/T30 SeriesThis generation achieved lower weight and higher strength than thin molded magnesium and was the ideal material for the A4 sized mobile ThinkPad T Series.

Fifth Generation (2005 -) X

ThinkPad Z60t SeriesFirst in the industry to use hybrid CFRP. This contributed to the development of a lighter A4 sized mobile than the ThinkPad T Series.

Sixth Generation (2008 -) X

ThinkPad X300/T400s SeriesHybrid CFRP improved. The need for design, weight and thin structure integrated at a high level.

Seventh Generation (2011 -) X

New ThinkPad T Series

CFRP supporting the progress of ThinkPad

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Our concept was to simplify this design into an integrated magnesium alloy frame. Actually, magnesium is not as strong as stainless steel or aluminum, but even if we use stronger metals, it is necessary to have seams and this results in reduced overall strength. By switching to an integrated frame, we can increase the overall rigidity even using magnesium.

Ohtani: Specifically, in the first generation ThinkPad Roll Cage, we have achieved a 30% reduction in the load applied to internal circuit boards by the frame.

—The ThinkPad Roll Cage first appeared in 2005. How has it developed since then?

Mizoguchi: The strength has improved a great deal. In the ThinkPad T400s, which featured an even thinner design, the system board that we have protected with the ThinkPad Role Cage is now also supported from beneath by a magnesium base cover. The ThinkPad Roll Cage itself is now stronger because we have integrated

it with the keyboard bezel, which was previously a separate part. These innovations have produced a reduction in the stress on major PC parts of 15%, even in thin notebook PCs (Figure 2).

Ohtani: This is also true for CFRP, but at Lenovo we are relentlessly working for progress in the areas of design and technology that support the reliability of ThinkPad.

—Could you tell us about the background behind developing this kind of frame?

Ohtani: In about 2003 or 2004 there was a sudden increase in problems of damage to the motherboards or hard disks of notebook PCs being used by our customers. Even though we are confident at Lenovo that our products have been tested over and over again before they are sent to market, it remained unclear to us what was causing this issue to occur repeatedly. We created a team to investigate and even went to the campus of an American university to observe how our notebook PCs were being used.

As a result, we came to understand that as the mobile use of PCs was expanding rapidly, PCs were being used in challenging ways that we had never expected. For instance, we saw a notebook PC that was still running being placed in a backpack and the user surprised us by getting on a bike and using the PC to listen to music. While you could say that this way of using our PCs exceeded our expectations, as a manufacturer, we have a responsibility to work towards reducing the problems that result from these new ways of using our product. We developed the ThinkPad Roll Cage as our solution to protecting the components inside the case from stress.

— Is the re a po in t o f v i ew characteristic of Lenovo that other companies do not have?

Ohtani: Well, Lenovo is often providing products for business use to companies. This allows us to get direct input through feedback from our customers. Our ability to design from the viewpoint of our customers is an important characteristic of Lenovo.

Mizoguchi : We have regular meetings that extend across the different sections in our company.We share information about what kinds of problems are coming up, offer opinions and search for solutions together. This all contributes to the products that we make. I think that might be a style which is fairly unique to Lenovo.

The inspiration for a breakthrough can be found in daily life

—How do you deal with it when you are stuck for ideas?

Mizoguchi: I try to forget work for a while and get refreshed. I like going for drives, so sometimes I go somewhere with my family. I also like diving and skiing, so I often enjoy sports.

—So as you begin to relax, you encounter new ideas?

Mizoguchi: Many times, something has caught my eye and I thought, “hey, I can use that.” For instance, one time I was on my way back from a drive and my headlights were foggy. I immediately consulted a dealer. He said that “there should not be any problem with this level of fog” and I asked why droplets of water were forming on the inside. Of course, headlights are sealed structures which allow the passage of air in order to respond to changes in air pressure, but use a material that does not allow the passage of water. At that point, I created an opportunity to speak with someone from the manufacturer of that material at

work. It occurred to me at that time that if we used that material for the sheet in notebook PC speakers, it would let air through, but would not allow water to pass through. This might eliminate the quick accumulation of foreign particles and dust. As a material, it is extremely fragile, and it does not appear that it can be used immediately, but I am working in cooperation with the materials manufacturer looking for a breakthrough.

Ohtani: Personally, I also often think about ease of use when I am touching the mobile phones and television remote controls around me. Ease-of-use is something that a lot of people do not think about. In fact, I think that the easier it is to use an object without thought, the more suitable it might be for humans. Even so, when you find a product that feels comfortable to use, it means that product was the result of an engineer thinking deeply until they thought their way through the design process. I am often asking myself when I touch the various products around me if they have sufficiently good ease of use or feel of use, what they are lacking and what I should focus on in the things that I am designing.

—Finally, could you offer us your principle for product design?

Mizoguchi: For me the key principle is “building trust”. By that, I mean the trust within the team and building trust with the members of other sections. Without that trust as a base, it is difficult to get my thoughts across. As a result of that trust, I think that we can achieve “products that are trusted by our customers.”

Ohtani: For me, the key word is “value”. Within Yamato Office, this is the value of my presence as an engineer. Within Lenovo, this is the value of the Yamato Office. And within the industry, this is the value of Lenovo. It is important for us to deeply recognize this and think about how we will communicate our value. Furthermore, we have to think about what kind of value we will provide our customers through Lenovo products. Isn't pursuing that the job of an engineer? In order to convince customers to select the product I have designed from amongst the many models and varieties of notebook PCs in the world, I face my work every day focused on providing value on a variety of levels.

A trustworthy product comes from the trust of those around you.

Fumitake Mizoguchi

The pursuit of value is the highest work of an engineer.

Tetsuya Ohtani

ThinkPad T400

Figure 2: Improvements to the ThinkPad Roll Cage

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In previous frames, mag-nesium was used in some areas and was being reinforced here and there using stainless steel or aluminum plates.

The ThinkPad Roll Cage is a frame made of mag-nesium alloy that boasts extremely low weight and high strength.

ThinkPad T400s

This figure displays in colors the stress applied throughout the PC when the PC is held in one hand in the logo area of the ThinkPad palm rest. The areas where a lot of stress is being applied are in red and in the ThinkPad T400s with the improved ThinkPad Roll Cage, there are less red areas. This is a reduction of 15% in the stress applied to major parts over the ThinkPad T400.

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