Building a better laptop computer

GE Plastics recently completed a study of 15 commercially available notebooks seeking to identify leading edge design systems. Called Operation Fulcrum (61), the study evaluated laptop technology development in the areas of thermal management, EMI shielding, thin-wall impact and processing, as well as design for manufacturing and assembly. The objective was to benchmark and quantify the requirements in each of these areas in order to evaluate the possibility of using new designs and concepts in the manufacturing of laptops. The key findings were as follows:

Thermal management:

Thermal systems for all notebooks focused on cooling the CPU. The best designs combined passive devices (heat sinks, heat pipes and heat spreaders) with active fan cooling. Laptops with fans have cooler surface temperatures than those without. Best thermal design had CPUs close to the sides of the enclosure, ample air for air circulation and a direct exit for air exhaust.

Shielding:

The emissions of all notebooks were measured with and without shielding, indicating that the required shielding is typically much less than the 60 to 80 dB generally perceived by industry to be necessary. The size and shape of apertures have a great impact on the shielding effectiveness of the enclosure. Emissions could be further reduced by the shielding of connectors, wires, power cords and adapters.

Thinwall:

The average wall thickness for laptop computers has dropped from 2.0 to 1.5 mm. Results showed a measurable but moderate reduction in impact strength in driving down to 1.5 mm wall sections. The drop off in impact performance was less for unfilled PC/ABS than for glass-filled PC.