I'm a bit shy of mentioning it here and giving the virus writers ideas, but indeed you can trash an LCD with video signals. A half-field-rate flashing black-white pattern would do it. Physics: LCDs invert every other field of video data; black areas get big AC signals, white areas get little AC signals. The video interface chips in the LCD panel do resampling, gamma correction, and convert the "DC" video levels to AC levels that alternate every field. The big AC signals align the LC molecules perpendicular to the display, while little signals let them relax to a horizontal position, so they can repolarize the light moving from the back polarizer to the front polarizer, making a path for the light. Thus, white = lowAC = relaxed molecules = polarization change = light. The problem comes if the drive signal has a DC component. That will electromigrate the LCD crystals perpendicularly, towards the face or the back of the display, and cause them to plate out. The screen turns black, and stays that way. This could be caused by feeding a field-synchronized video signal that was black in even fields (making a positive voltage, say) and white in odd fields (making no voltage). A few minutes of this will leave a pattern permanently ghosted into the display. This might be something for video driver writers to be cognisant of. Keith -- Keith Lofstrom keithl@xxxxxxxx Voice (503)-520-1993 KLIC --- Keith Lofstrom Integrated Circuits --- "Your Ideas in Silicon" Design Contracting in Bipolar and CMOS - Analog, Digital, and Scan ICs
