1. Field of the Invention
This invention relates generally to the removal of heat from electronic components, and more particularly, to the removal of heat from a first computing device housing member to a rotatably attached second computing device housing member.
2. Description of the Related Art
Higher levels of integration and improved processing technology produce increasingly complex integrated circuits. These new generations of integrated circuits often operate at higher frequencies and generate more heat than their predecessors. These thermal problems are compounded by increasing power (and therefore increasing heat generation) from microprocessors, increasing power from other components (e.g., graphics and memory), and by reductions in the form factor of computing devices (e.g., the move toward thinner and lighter notebook computers). Typically, heat sinks, fans, and heat pipes are employed to dissipate heat from integrated circuits and other electronic components. Increases in heat generation are often accompanied by simply increasing the quantity or size of these heat dissipation elements. The relatively small size of a portable computing device, however, complicates heat dissipation by limiting airflow, crowding heat generating components, and reducing the space available for heat dissipation devices.
A portable computing device typically includes two computer housing members that are rotatably coupled by a hinge. The first member, a computer base, usually has an input device such as a keyboard or a touchpad as well as a number of electronic components. Integrated circuits with the highest clock frequency are typically located in close proximity to each other within the computer base. Accordingly, there is a region in the base having a level of heat generation greater than that of the rest of the computing device.
Since the computer base size is generally kept to a minimum, and the computer base contains both the input device and numerous other electronic components, there may be inadequate space to dissipate enough heat to keep the electronic components within their acceptable range of operating temperatures. Heat dissipation through the bottom of the base is limited because the computer is usually operated on a relatively flat surface. Also, the input device (e.g. keyboard) can limit the heat flow through the top of the base. The traditional horizontal operating position adds to the difficulty of dissipating heat from the computer base when the lid of the notebook is closed, an operating position that arises when the computer is docked or a port replicator is used.
The second member, a computer display, is typically in a substantially vertical position during computer operation. The display contains an output device, such as a screen, and some additional computer circuitry. In most computing devices, the screen and the other circuitry in the display do not generate more heat than can be dissipated given the surface area available and the relatively vertical position of the display. Thus, additional heat from the base could be dissipated in the display if transferred from the base to the display.
The main difficulty in transferring heat between the base and the display is that many efficient heat conductors, such as heat pipes, are not sufficiently flexible to accommodate the repetitive motion expected between the hinged base and display of the computing device. Efforts have been made to otherwise connect a heat pipe from the base of a computing device to a heat pipe in the display. One such effort is discussed in U.S. Pat. No. 5,646,822,which is assigned to the present assignee. The mating of heat pipes described in the '822 patent requires a connector or a thermal hinge to be added between the base and display of the computing device. Connecting one heat pipe to another at a hinge is mechanically complex. Assembly and disassembly of the computing device (e.g. for servicing in the field) is further complicated by the pipe-to-pipe connection at the hinge.
The present invention is directed to overcoming, or at least reducing the effects of, one or more of the problems set forth above.