Tearing Down Waterproof Mobile Phone [Part 1]

Mar 17, 2008
Nikkei Electronics Teardown Squad
From left to right - main body, water proofing mechanism, first main board, second main board, camera module
From left to right - main body, water proofing mechanism, first main board, second main board, camera module
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The Nikkei Electronics Teardown Team will tackle mobile phones released in February 2008.

Our first target is the W61CA from KDDI Corp. Like the SO905iCS (Cyber-shot phone), the camera is one of the main features of the W61CA. The handset has an image sensor featuring an effective pixel count of 5.15 Mpixels, which is on par with that of the SO905iCS.

The W61CA is reportedly equipped with an image processing LSI dubbed "EXILIM engine for Mobile," which is prefixed with the brand name of Casio Computer Co Ltd's digital camera "EXILIM." The handset, however, is not equipped with an optical zoom function unlike the SO905iCS, and the capacity of its built-in memory is limited.

Instead, the W61CA has the one-segment reception capability and other functions, which are not offered by the SO905iCS. The biggest feature among them is the waterproof property, which allows the use in bathroom, etc (Note 1). In the breakdown operation, we took a closer look at the waterproofing mechanism and discovered structures carefully designed to maintain water tightness inside the chassis.

(Note 1) According to Casio Computer, which manufactures the handset, the waterproofing performance of the W61CA meets the IPX5 and IPX7 protection levels set by the Japanese Industrial Standards (JIS). The former level is set to meet the requirement where "the W61CA will not be adversely affected even if it is directly subjected to water jetting from any direction under the condition that approximately 12.5L/min of water is supplied for more than three minutes from a distance of about 3m by using a nozzle with an inner diameter of 6.3mm." The latter category is designated so that "the internal part of the main body remains dry and the W61CA should maintain its functionality as a phone even if it is immersed to a depth of 1m into a still-water tank containing tap water at room temperature and left quietly at the bottom for about 30 minutes."

The internal structures of the product, ie the water proofing mechanism, main boards and camera module, are introduced in this order in the following pages. The test was carried out with cooperation from Fomalhaut Techno Solutions (Koto Ward, Tokyo).