CRT Monitor (Philips 109B65 Monitor 19IN18V CRT 25MM 1920X1440 MNTR60HZ BLACK VGA PC MAC REA)
Graphical displays for early computers used vector monitors, a type of CRT similar to the oscilloscope but typically using magnetic, rather than electrostatic, deflection. Magnetic deflection allows the construction of much shorter tubes for a given viewable image size. Here, the beam traces straight lines between arbitrary points, repeatedly refreshing the display as quickly as possible. Vector monitors were also used by some late-1970s to mid-1980s arcade games such as Asteroids. Vector displays for computers did not noticeably suffer from the display artifacts of Aliasing and pixelation, but were limited in that they could display only a shape's outline (advanced vector systems could provide a limited amount of shading), and only a limited amount of crudely-drawn text (the number of shapes and/or textual characters drawn was severely limited, because the speed of refresh was roughly inversely proportional to how many vectors needed to be drawn). Some vector monitors are capable of displaying multiple colors, using either a typical tri-color CRT, or two phosphor layers (so-called "penetration color"). In these dual-layer tubes, by controlling the strength of the electron beam, electrons could be made to reach (and illuminate) either or both phosphor layers, typically producing a choice of green, orange, or red.
CRT monitor screen size