Chia S Lin

US Patent:

6535126, Mar 18, 2003

Filed:

Dec 15, 2000

Appl. No.:

09/738306

Inventors:

Chia Cheng Lin - Allison Park PA
Thomas G. Rukavina - Verona PA
Yu Jiao - Pittsburgh PA

Assignee:

PPG Industries Ohio, Inc. - Cleveland OH

International Classification:

G08B 1300

US Classification:

340550, 3405454, 359269, 359273

Abstract:

An electrochromic window assembly includes a security system for monitoring breakage of the electrochromic window assembly. Control circuitry is connected to the electrochromic window assembly for monitoring an electrical characteristic of one or more conductive coatings within the electrochromic window assembly, such as electrical resistance. Upon detecting a change in the electrical resistance, such as that caused by a break in one or more conductive coating, an alarm signal is generated and is sent to an alarm trigger circuit for activating an alarm. A method for monitoring penetration or breakage of an electrochromic window assembly is also provided, which method involves applying electrical activation to an electrochromic assembly and monitoring for a change in an electrical characteristic based on the applied electrical potential. Electrochromic window assemblies incorporating security alarm features in accordance with the present invention are particularly useful in automobile applications.