Question: Where is the headquarters of the company that unveiled a 2-in-1 convertible tablet at the 2013 IFA in Berlin, Germany?

Context articles: Samsung Galaxy Note (original)
Sony Xperia Tablet S
Lenovo
ThinkPad Helix
Lenovo Yoga 2 Pro
2-in-1 PC
Sony Xperia Z3 Tablet Compact
2013 IFA Shield
ThinkPad Twist
ThinkPad Yoga

The Samsung Galaxy Note is an Android smartphone produced by Samsung Electronics.
 Unveiled at IFA Berlin 2011, it was first released in Germany in late October 2011, with other countries following afterwards.
 The Galaxy Note was distinguished by unusually large form factor—later referred to using the term "phablet"—which straddled the size of the average smartphone at the time, and that of a small tablet: it features a 5.3-inch display, and is bundled with a stylus branded as the "S Pen", which can be used to navigate the device's user interface, and write or draw in supported apps.
The Xperia Tablet S is a touchscreen Android tablet designed by Sony.
 It was announced at Internationale Funkausstellung Berlin (IFA) 2012, and debuted in the US on September 7, 2012.
 The tablet directly succeeded the Sony Tablet S, with a thinner and lighter design, a faster processor, and an improved camera.
 It is the first Sony tablet to be marketed with the Xperia branding.
Lenovo Group Ltd. or Lenovo PC International or shortened as Lenovo ( ; formerly stylized as lenovo) is a Chinese multinational technology company with headquarters in Beijing, China and Morrisville, North Carolina.
 It designs, develops, manufactures and sells personal computers, tablet computers, smartphones, workstations, servers, electronic storage devices, IT management software, and smart televisions.
 Since 2013, Lenovo is the world's largest personal computer vendor by unit sales.
 It markets the ThinkPad line of notebook computers, IdeaPad and Yoga lines of notebook laptops, and the IdeaCentre and ThinkCentre lines of desktops.
Lenovo ThinkPad Helix refers to two generations of 2-in-1 convertible tablets that can be used as both a conventional ultrabook and a tablet computer.
 The first-generation Helix was announced at the 2013 International CES and was released on 21 May 2013.
 A second-generation Helix came out in 2014.
The Lenovo IdeaPad Yoga 2 Pro is an Ultrabook-class convertible device that can be used as both a tablet and laptop computer.
 Lenovo unveiled the Yoga 2 Pro at the 2013 IFA in Berlin, Germany.
 It went on sale in the United States in October 2013.
 It comes in two colors, silver gray and clementine orange, and is designed for flexibility—allowing the user to use it in a variety of situations.
 Because of the durable hinge that allows the screen to swivel 360 degrees, the Yoga 2 Pro is able to fully utilize windows 8 and its emphasis on touchscreen integration.
 The Yoga 2 Pro is the first laptop to earn a Green Mark certification from TUV that recognizes Lenovo for environmentally friendly manufacturing processes, and low energy consumption.
A 2-in-1 PC, also known as a 2-in-1 tablet, 2-in-1 laptop, 2-in-1 detachable, laplet, or simply 2-in-1, is a portable computer that shares characteristics of both tablets and laptops. Before the emergence of "2-in-1s," the terms "convertible" and "hybrid" were already in use by technology journalists.
 The term "convertible" typically referred to 2-in-1 PCs that featured some type of keyboard concealment mechanism that allowed the keyboard to be slid or rotated behind the back of the chassis, while the term "hybrid" typically referred to devices that featured a hot-pluggable complimentary keyboard.
The Sony Xperia Z3 Tablet Compact is a waterproof & dustproof compact Android tablet manufactured and designed by Sony.
 It was unveiled during a press conference at IFA 2014 on September 3, 2014 along with the Xperia Z3 and Xperia Z3 Compact.
 It is the manufacture's first 8.0 inch (203.2 mm) tablet.
 The tablet was the winner of the Reddot Award 2015 for the product design.
The 2013 IFA Shield is the 117th edition of the IFA Shield.
 The tournament this season is being held from 4 March 2013 in West Bengal.
 This year also, the Indian Football Association announced that two foreign clubs would participate in the tournament, Costa Rican Primera División club Deportivo Saprissa and Bangladesh Premier League club Muktijoddha Sangsad.
 However on 4 March 2013 it was announced that Muktijoddha Sangsad would not participate in this tournament and instead current I-League club ONGC would take their place.
The ThinkPad Twist is a 2-in-1 convertible tablet, that can function as a laptop and tablet released in 2012.
 The Twist is designed for business users and runs Microsoft's Windows 8 operating system.
The ThinkPad Yoga is a 2-in-1 convertible tablet from Lenovo unveiled in September at the 2013 IFA in Berlin, Germany.