[MacBook Air Teardown] No Frame Supports Keyboard From Beneath [Part 9]

Aug 14, 2008
Atsushi Ooshima

Secret of the slimness

When viewed edge-on, the thickest part of the body is about 12.5mm thick. This part is sunken because of the keyboard, leaving smaller than expected space inside. The bottom plate is about 0.8mm thick. Because the mesh-like rib, to which the keyboard is attached, is as thick as 2.0mm, the space below the keyboard part is only 5.0-7.8mm high. Please see the figures to know how the parts are placed in this small space.

In normal notebook PCs, a frame is used to support a keyboard from beneath. However, in the MacBook Air, the keyboard is hung from the aluminum rib (cross section: 2.2mm (W) × 2.0mm (H)), omitting a frame below the keyboard. This is one of the main characteristics of the notebook's structure, contributing to its slimness.

The membrane switch part of the keyboard, combined with a light guide plate that illuminates the keys, is 1.0mm thick. The membrane switch part is so flabby that it bows by its own weight. Therefore, that part is attached to the mesh-like rib with about 50 screws so as not to be deformed by keying pressure.

Also, the adoption of a Li-polymer secondary battery, which can be designed thin and in the shapes other than a cylindrical shape, is essential to realize the slim body.

NOTE: This article is a translation of an article published in the summer 2008 issue of Nikkei Board Guide. The numbers and part names in the text were estimated by the staff of the magazine.