Rainbow Effect

An artifact associated with visual display screens and rear-projection DLP front. Fortunately, only a few people may view these momentary flashes of color and even fewer people can be distracted by this "rainbow". For some individual, this rainbow usually occurs when the eyes of the viewer deviate sharply from the screen. The rainbow is a consequence of the use by the DLP of a color wheel that causes the three primary colors - red, green and blue - are projected consecutively rather than continuously. The latest DLP screens have incorporated advanced technology in color wheel, which minimizes this effect.

Like some people are sensitive to televisions and flourescent lights flickering (flicker fusion threshold), some people are sensitive to the rainbow effect. This problems is greatly reduced by inreasing the speed of the colour wheel and increasing the number of or colour segments, hence "7 segment, 5 speed" colour wheels.

It is most likely to be seen when bright objects are over layed on a dark background or one’s eyes pan across an image. Aside from the visual distraction, the rainbow effect can cause headaches and eye strain.

DLP consumer electronics manufacturers use a number of tactics to combat the rainbow effect including:

• Faster color wheel speeds
• More color segments
• Archimedian spiral sectors on color wheel