Abstract: An electronic device includes a substrate, an upper conductive layer, and a lower conductive layer. The substrate has a plurality of inner vias and has an upper surface and a lower surface. The upper conductive layer includes an upper ground trace and an upper signal pad disposed on the upper surface. The upper ground trace is electrically connected to the ground vias and has an upper hollow portion exposing a part of the upper surface. The upper signal pad is disposed on the part of the upper surface exposed by the upper hollow portion and electrically connected to the signal via. The lower conductive layer includes a lower ground trace and a lower signal pad disposed on the lower surface. The lower conductive trace is electrically connected to the ground vias and has a lower hollow portion exposing a part of the lower surface. The lower signal pad is disposed on the part of the lower surface exposed by the lower hollow portion and electrically connected to the signal via.

Abstract: The laptop includes a host, a screen and a heat dissipation structure. The screen is pivotally connected to the host and includes a clamp member. The heat dissipation structure is connected to the host adjacent to where the screen is pivotally connected and covers a back of the host. The heat dissipation structure includes a back case body and a hatch cover. The back case body defines a heat dissipation opening. One side of the hatch cover is pivotally connected to the back case body. The hatch cover is set to match the heat dissipation opening. When the screen is closed with respect to the host, the clamp member urges the hatch cover to close the heat dissipation opening; when the screen is open with respect to the host, the clamp member is released from the hatch cover, and the hatch cover rotates to expose the heat dissipation opening.

Abstract: The laptop includes a host, a screen and a heat dissipation structure. The screen is pivotally connected to the host and includes a clamp member. The heat dissipation structure is connected to the host adjacent to where the screen is pivotally connected and covers a back of the host. The heat dissipation structure includes a back case body and a hatch cover. The back case body defines a heat dissipation opening. One side of the hatch cover is pivotally connected to the back case body. The hatch cover is set to match the heat dissipation opening. When the screen is closed with respect to the host, the clamp member urges the hatch cover to close the heat dissipation opening; when the screen is open with respect to the host, the clamp member is released from the hatch cover, and the hatch cover rotates to expose the heat dissipation opening.