Water exposure is among major reasons that may cause significant malfunction of devices, such as electronic devices, which include electronic, mechanical, or chemical components. Therefore, verification of significant water exposure (or water immersion) is important to manufacturers of the devices. For example, for purposes such as warranty claim assessment, trouble-shooting for repairs, and product development, a manufacturer of electronic devices typically needs to verify whether a malfunctioning device has been immersed in water. FIGS. 1A-B illustrate an example conventional arrangement for verifying water immersion of a device 100 such as a cellular phone.
As illustrated in FIGS. 1A-B, device 100 includes a compartment 105 with a cover 108 for housing a removable module 110 such as a battery. For verifying water immersion, device 100 may include a detector 102 disposed at a bottom of compartment 105. To determine whether device 100 has previously been immersed in water, an inspector 170, such as a representative of the manufacture of device 100, may open cover 108 and remove removable module 110 to see whether detector 102 has changed color.
Detector 102 may be commercially available from suppliers such as 3M Company (www.3m.com) of St. Paul, Minn. and Schreiner Label Tech, Inc. of Southfield, Mich., and NovaVision Inc. (www.novavisioninc.com) of Bowling Green, Ohio and typically has a configuration as illustrated in FIG. 1B.
FIG. 1B illustrates a cross-sectional view of detector 102, with dimensions of detector 102 exaggerated for clear illustration. As shown in FIG. 1B, detector 102 includes an adhesive layer 132 for securing detector 102 at the bottom of compartment 105. Over adhesive layer 132, detector 102 includes a dye layer 112 that may dissolve after receiving a certain amount of water. Over dye layer 112, detector 102 includes a paper layer 122 for bearing dye layer 112 as well as allowing dissolved dye layer 112 to diffuse (or permeate) through paper layer 122 to show an indication (such as a red spot) that is visible to inspector 170 after detector 102 has been significantly exposed to (or immersed in) water. Over paper layer 122, detector 102 includes a transparent cover layer 142 for limiting exposure of paper layer 122 to humidity, thereby further avoiding false positives.
Nevertheless, the above-described conventional arrangement for verifying water immersion with detector 102 has disadvantages. The disadvantages may pertain to limited application, tampering of detection 102, and complicated inspection process, described as follows.
Firstly, application of the conventional arrangement is limited to devices that are designed to be easily opened. However, subject to requirements such as industrial standards, design considerations, or manufacturing considerations, some devices cannot be opened without being dismantled or damaged. Therefore, water immersion of some devices cannot be verified using the conventional arrangement.
Secondly, since detector 102 is readily visible and accessible with easy removal of removable module 110, detector 102 may be easily tampered. For example, detector 102 may be replaced with a new detector after device 100 has been immersed in water. As a result, it may become difficult for the manufacturer of device 100 to verify or prove water immersion of device 100.
Thirdly, the process of water immersion verification may be complicated. When the representative of the manufacturer is to inspect detector 120, the representative must remove cover 108 and removable module 110 before inspection. The representative may also need to make sure that cover 108 and removable module 110 are replaced back to device 100 after the inspection. Accordingly, the inspection process is complicated, and the inspection process may be further complicated when the representative handles multiple devices.