Dual-Scan display

A dual-scan display, which is sometimes referred to as a passive matrix display, has a row of transistors running on the top of the screen (x-axes) as well as the left of the screen (y-axes). The amount of transistors are defined by the LCD manufacturer, for example, the manufacturer may define 800 transistors along the x-axes and 600 transistors along the y-axes. These transistors power the pixels that are powered in grids by the transistors. Unfortunately, if one of these transistors were to fail, you would receive a solid black line going vertical or horizontal.

When compared to an Active Matrix, most Passive Matrix is superior technology. With Passive matrix you are unable to see the screen unless you are directly in front of it. Generally however the display is going to be dimmer than a Passive Matrix.

New Passive Matrix screen technologies, such as CSTN (Color Super-Twisted Nematic), DSTN (Double Layer Super-Twist Nematic), and HPA (High-Performance Addressing displays) are improved versions of the Passive Matrix displays that improve upon previous versions by offering higher contrast / brightness rates found with earlier versions.

In conclusion, the Passive Matrix today, while better than previous versions, is still an affordable solution as an LCD display. However, it does not offer the quality that is found with Active Matrix.

• Additional help and information with LCD displays can be found on our LCD help page.

Also see: Video definitions