The fact that light is an electromagnetic wave that is visible to the eye is one basic principle that liquid crystal displays are based. Light sources emit the light waves in numerous directions or axis as represented by the series of arrows originating from the source shown above. Adding to that, each wave can be broken down to its orthogonal components meaning that each vector has a vertical and horizontal component to it. If a wave with a completely aligned vertical axis was examined its horizontal component would be zero. The reverse is also true regarding a wave aligned on the horizontal axis. Its vertical component is zero. Polarization relates to the orientation of the light waves and a polarizing filter allows only waves aligned on the specific axis to pass. The diagram above shows the result of two polarizing filters oriented 90 degrees out of phase. The first filter passes only the light waves that have a vertical orientation. The second filter will block the remaining light since that vertical waves have no horizontal component.