Pixel Pitch and Resolution
These two terms can generate confusion because they seem to mean the same thing. However, one refers to the physical space between the picture elements (pixels) and the other refers to the display’s output clarity. Let’s look at how these terms apply to displays like LCDs and Plasma.
Pixel Pitch
Pixel pitch is the physical distance between the pixels (picture elements) in a display device. If it’s not given in the specifications, it’s the display’s Active Area divided by the number of pixels. Pixel pitch can affect viewability when viewing large displays up close because in some displays (plasma, more so than LCD) the pixels do not blend well and spaces between them can be discerned. It’s for this reason that giant LED displays look beautiful from a distance but get uncomfortable to view when you approach.
For instance, pixel pitch in a plasma display must be carefully managed, as larger pixels consume more current in this type of display (creating a need for larger power supplies and therefore more heating); and when building smaller plasma panels, pixels become size-limited due to the lower light output of the smaller elements.
LCDs can be made in all sizes with a much narrower pixel pitch, because the sub-pixels are much closer together, due to miniaturized circuit runs between the switching elements. CRTs can have extremely small pixel pitches because the phosphor dot arrangements are separated by only a few microns of space on the face of the CRT. Monochrome CRTs will always remain the king of high-resolution displays, because (with the right electronics) you can literally address each individual molecule of the screen phosphor.
Some large plasma displays can be uncomfortable to watch up close due to the large amount of space between the pixels; and when the viewer is close enough to be able to distinguish these individual pixels, the inherent qualities of the display begin to be lost – because you begin to distinguish the bright emitters and the dark spaces in between.
Definition and Resolution
The term “resolution” is a frequent cause of confusion. It is often used interchangeably to describe both the definition of the signal density (incorrectly, as in a “high-resolution video feed”) and a display device’s maximum capability; known as resolution. Adding to the confusion is that both are expressed in horizontal pixels × vertical pixels.
In LCDs, the panel’s resolution is known as “native resolution” because the panel electronics cannot perform any interpolation to resize (or more accurately, redefine) an image for display. It’s up to the electronics driving the display to perform this function. This means the processing quality of the display electronics can figure heavily in how any given signal looks on an LCD or plasma screen. Since all signals look best with minimal processing, the native resolution is the preferred display format.
Some displays (typically DLP), can operate with great success at higher resolutions because through new firmware, they are able to not only re-scale any incoming signal, but also offer the enhancement of precisely dithering the reflected light from the DLP mirror array allowing them to resolve a higher definition image.