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Posted: May 28, 2000
Written by: Tuan "Solace" Nguyen
Aperture grille technology has the same intentions as shadow masks, to prevent pixel glow leakage. The technology is made up of thousands of thin vertical metal alloys wires that run horizontally across the screen. The phosphor screen itself runs in stripes along with the grille.
This has the same effect as shadow masks but because there is less resistive material, the resulting image has higher contrast and brightness and gives overall better color vibrancy than shadow masks. But because the actual RGB phosphor strips themselves do not have interruptions like shadow masks, the sharpness of the electron beam itself must define the top and bottom of each pixel. Some say this causes blurriness but currently at 0.22mm dot pitch, aperture grille has the sharpest visuals of the two technologies.
Another advantage aperture grilles have over shadow masks is that they only need to be curved horizontally instead of both planes. However, all this comes at a price. Each grille wire is stretched vertically very tightly to ensure that wire "shimmering" doesn't occur and that a sharp image is produced. But when the wires heat up from the beam, they expand and slack -- loosen a bit. This contracting and expanding causes a severe wave or vibration effect. To counter this, aperture grille displays employ damper wires that keep the grille wires from moving. There are two damper wires to every aperture grille display. And because of this, they are noticeable when a light color is being displayed. If you have a Trinitron based display, you probably have already noticed two faint lines running across your screen, dividing the screen into three.
While this can be an annoyance, it really depends on for what you're using your monitor. If you're an AutoCAD user, you may find the lines very distracting when doing precise drawings. However, if you're just into rapping people with your rail gun, then the lines should pose no problems at all. Some people actually like the lines saying that it gives them the "aperture class". I don't know if this is actually a good thing to boast about but, what can I say?
Your Best Pitch
You often hear companies refer to the sharpness of their monitors in "dot-pitch". This is the measurement of how close each pixel is to another -- the closer they are, the sharper the resulting image. When comparing dot-pitch, you must consider which technology the monitor is based on -- aperture grille or shadow mask. Each technology has its own way of defining dot-pitch.