Editing Trinitron (section)

==Description==
===Basic concept===
The Trinitron design incorporates two unique features: the single-gun three-cathode picture tube, and the vertically aligned [[aperture grille]].

The single gun consists of a long-necked tube with a single electrode{{dubious|By definition and electronic gun consists of multiple electrodes|date=December 2017}} at its base, flaring out into a horizontally-aligned rectangular shape with three rectangular cathodes inside. Each cathode is fed the amplified signal from one of the decoded RGB signals.

The electrons from the cathodes are all aimed toward a single point at the back of the screen where they hit the aperture grille, a steel sheet{{dubious|It has already been ascertained that an array of fine wires is used, not a steel sheet|date=December 2017}} with vertical slots cut in it. Due to the slight separation of the cathodes at the back of the tube, the three beams approach the grille at slightly different angles. When they pass through the grille they retain this angle, hitting their individual colored phosphors that are deposited in vertical stripes on the inside of the faceplate. The main purpose of the grille is to ensure that each beam strikes only the phosphor stripes for its color, much as does a shadow mask. However, unlike a shadow mask, there are essentially no obstructions along each entire phosphor stripe. Larger CRTs have a few horizontal stabilizing wires part way between top and bottom.

===Advantages===
In comparison to early shadow mask designs, the Trinitron grille cuts off much less of the signal coming from the electron guns. RCA tubes built in the 1950s cut off about 85% of the electron beam, while the grille cuts off about 25%.{{citation needed|date=December 2017}} Improvements to the shadow mask designs continually narrowed this difference between the two designs, and by the late 1980s the difference in performance, at least theoretically, was eliminated.{{citation needed|date=December 2017}}

Another advantage of the aperture grille was that the distance between the wires remained constant vertically across the screen. In the shadow mask design, the size of the holes in the mask is defined by the required resolution of the phosphor dots on the screen, which was constant. However, the distance from the guns to the holes changed; for dots near the center of the screen, the distance was its shortest, at points in the corners it was at its maximum. To ensure that the guns were focused on the holes, a system known as dynamic convergence had to constantly adjust the focus point as the beam moved across the screen. In the Trinitron design, the problem was greatly simplified,{{how|date=December 2017}} requiring changes only for large screen sizes, and only on a line-by-line basis.

For this reason, Trinitron systems are easier to focus than shadow masks, and generally had a sharper image.{{citation needed|date=December 2017}} This was a major selling point of the Trinitron design for much of its history. In the 1990s, new computer-controlled real-time feedback focusing systems eliminated this advantage, as well as leading to the introduction of "true flat" designs.

===Disadvantages===
====Visible support or damping wires====
Even small changes in the alignment of the grille over the phosphors can cause the color purity to shift. Since the wires are thin, small bumps can cause the wires to shift alignment if they are not held in place. Monitors using Trinitron technology have one or more thin tungsten wires running horizontally across the grille to prevent this. Screens 15" and below have one wire located about two thirds of the way down the screen, while monitors greater than 15" have 2 wires at the one-third and two-thirds positions. These wires are less apparent or completely obscured on [[Standard-definition television|standard definition]] sets due to wider [[scan line]]s to match the lower resolution of the video being displayed. On computer monitors, where the scan lines are much closer together, the wires are often visible. This is a minor drawback of the Trinitron standard which is not shared by shadow mask CRTs. Aperture grilles are not as mechanically stable as shadow or slot masks; a tap can cause the image to briefly become distorted, even with damping/support wires.<ref name="stweb.peelschools.org"/> Some people may find the wires to be distracting.<ref>{{Cite web|url=https://books.google.com/books?id=4wEAAAAAMBAJ&q=aperture+grille+blocks&pg=PA64|title = Maximum PC|date = July 2003}}</ref>

====Anti-glare coating====
A polyurethane sheet coated to scatter reflections is affixed to the front of the screen, where it can be damaged.{{Citation needed|date=June 2020}}