Patent ID: 8920963

Claim:
A portable device for use with a communication peer, the portable device comprising: an electronic component that performs predetermined wireless communication with the communication peer; a battery that powers the electronic component; and a case that accommodates the electronic component and the battery, wherein the case includes: a case body including a battery compartment that accommodates the battery, wherein the battery compartment includes an opening formed in one side of the case body; a battery lid that covers the opening of the battery compartment; and an elastic waterproof seal formed integrally with the battery lid and surrounding the opening of the battery compartment, wherein the battery lid is coupled to the case body in a direction perpendicular to a radial direction of the waterproof seal; a rim formed around the opening of the battery compartment pushes the waterproof seal and elastically deforms the waterproof seal in an inward radial direction when the battery lid is coupled to the case body; and the waterproof seal produces an elastic repulsive force when elastically deformed in the inward radial direction, and the elastic repulsive force pushes against an inner wall of the battery compartment in an outward radial direction to keep the battery lid in a state coupled to the case body and to seal a gap between the battery lid and the case body in a liquid-tight state, wherein the waterproof seal includes a flexible groove that extends entirely along the waterproof seal and opens in a direction perpendicular to the radial direction.