Prismatic Auto Mirror Cuts Headlight Glare (Sep, 1950)
This is one idea that certainly stuck around.
Prismatic Auto Mirror Cuts Headlight Glare
Glare in the rear-view mirror from the headlights of the car behind is cleverly avoided by the mirror above. Front and back surfaces of the mirror are not quite parallel; in section, the mirror is slightly wedge-shaped. For daytime, bright-reflection use, the mirror is set so that you See the bright image that bounces off its silvered rear surface in the conventional way. At night the mirror is tipped up a little so that you see the dimmer, front-surface reflection â€”the same weak reflection you can see in store windows and unsilvered glass. The mirror, mounted so that it snaps easily to either position, was developed by General Motors’ Guide Lamp division.