Electromagnetic Interference Shields for Electronic Devices

Abstract

An EMI shield for personal computers, cellular telephones, and other electronic devices is constructed from thermoformable polymeric material which is then metallized on all surfaces by vacuum metallization techniques to provide an inexpensive, lightweight, yet effective EMI shield.

Description

CROSS-REFERENCES TO RELATED APPLICATIONS [0001] This application is a continuation of application Ser. No. 10 / 659,838, filed Sep. 10, 2003, which is a continuation of application Ser. No. 09 / 732,235, filed Dec. 7, 2000, now U.S. Pat. No. 6,624,353, which is a continuation of application Ser. No. 08 / 958,595, filed Oct. 29, 1997, now U.S. Pat. No. 6,570,085, which is a division of application Ser. No. 08 / 463,297, filed Jun. 5, 1995, now U.S. Pat. No. 5,811,050, which is a continuation-in-part of application Ser. No. 08 / 254,250, filed Jun. 6, 1994, now abandoned, the complete disclosures of which are incorporated herein by reference in their entirety for all purposes.BACKGROUND OF THE INVENTION [0002] This invention pertains to shielding apparatus for containing high frequency electromagnetic radiation within a personal computer, cellular telephone, or other electronic instrument. [0003] Electromagnetic compatibility (EMC) is a broad term used to describe electromagnetic interference (...

AI Technical Summary

Benefits of technology

This patent is about a method for making an EMI shield for electronic devices. The shield is made by thermoforming a polymer sheet and then metallizing it using vacuum metallizing techniques. The resulting shield is lightweight, flexible, and can be easily replaced if damaged. The method allows for the shield to be shaped and metallized to effectively dissipate EMI. The patent also mentions that different polymers can be used for the shield, such as ABS, polystyrenes, and cellulose polymers, and that fillers like carbon black and metal fibers can enhance the shield's ability to absorb EMI. The metallized shield can be coated with additional materials like conductive tape or gaskets, and can be secured using conductive adhesive, laser welding, or heat sealing. The resulting shield is easy to manufacture, lightweight, and resistant to corrosive atmospheric conditions.

Problems solved by technology

Conventional thin-film vacuum metallizing is not adequate to dissipate EMI.

Existing equipment for metallizing thermoformed shapes for ornamental reflective appearance purposes is not suitable for application of relatively thick thin film as is required to provide suitable surface impedance to allow effective EMI dissipation.

Images