Toshiba has introduced a new “VACF” display option on its Tecra M3 series of business notebooks.
The VACF (Viewing Angle Control Filter) feature may be turned on or off as needed. When enabled, it limits display readability, allowing the screen to be viewed only by someone sitting directly in front of the computer. Anyone sitting to either side sees a brightly lit checkerboard pattern, making the true screen contents indecipherable.
The point of VACF is, of course, security. It will be interesting to read reviews to find out whether VACF has any negative impact, e.g. on screen sharpness or battery life.
More about the Tecra M3 with VACF may be found in this Toshiba news release.
FWIW, the VACF feature would not be needed on my Tecra M4 laptop - the polycarbonate display on this system does a plenty good enough job of restricting viewing angles on its own.