[Magic Mouse Teardown (1)] Struggling With Double-sided Tape
Nikkei Electronics Teardown Squad started to break down the Magic Mouse, a computer mouse that features a touch sensor and was released by Apple Inc at the end of October 2009.
First, we removed the bottom cover and batteries but could not find any screws. We thought that the parts were fitted into one another without using any screws and took off two black resin parts that were attached to the bottom surface and parallel to each other.
The resin parts are the "legs" of the mouse and made of a slippery material. Due to their softness, they were considerably deformed when being removed. At this point, we gave up the idea of reassembling the mouse.
Next, we began to peel off an aluminum-alloy bottom cover from the bottom frame made of resin. The bottom cover was attached by strong double-sided tape. We inserted a flat-blade screwdriver into the gap between the bottom cover and the bottom frame and separated them by sheer force.
Finally, we could see the mechanical structure of the Magic Mouse. It can be separated into (1) the resin bottom frame that serves as a battery case and is equipped with circuit boards and (2) the top frame embedded with a touch sensor, and they are connected with a hinge. We looked into a small gap between the two frames to find the hinge and removed it with the flat-blade screwdriver to separate the two frames.
After pulling out an electrode sheet (flexible substrate) for the touch sensor from the connector connecting circuit boards, the top and bottom frames were separated. The connector is a so-called "back-lock type." And it is unlocked when the plate positioned opposite to the slot is lifted.
Furthermore, the connector is fixed between the circuit board and the flexible substrate by double-sided tape. The plate of the lock mechanism is printed with "DDK," indicating that the connector is manufactured by DDK Ltd.
"When a flexible substrate using a front-lock connector is pulled upward, the connector is likely to be unlocked, detaching the flexible substrate," an engineer said. "Considering the structure of the Magic Mouse, it is possible that such a force is applied when it is being assembled. So, Apple probably employed the back-lock connector to prevent it."
Another engineer said that the terminal area of the flexible substrate is very small and it requires a considerable skill to infallibly connect it. It is more difficult to insert a flexible substrate with a back-lock connector than that with a front-lock connector.
"The Magic Mouse has a design that imposes a burden on workers," an engineer said. "There must be many high-quality workers at Apple's subcontract factories."
The upper part of the Magic Mouse is made by using double-sided tape to attach a black resin frame on a white resin cover that seems to be made of polycarbonate, and the electrode sheet for the touch sensor is positioned between them. We carefully inserted a tool into a gap between the frame and the cover and started to remove the frame.
Correction Notice: We guessed that the connector for the flexible substrate does not have a lock mechanism. However, with help from a reader, we found a lock mechanism and changed the article accordingly.