LCD Display Pixel Term, Resolution & Aspect Ratio


Introduction: LCD Resolution

What is the Native Resolution of a LCD Display?

In order to understand the native resolution of a LCD display, it will be better to understand a little about the LCD display technology, especially TFT LCD manufacturing process. First, we need to understand what are pixels.

What Are Pixels?

Pixel, also called Picture Element, A pixel is the smallest unit of a digital image or graphic that can be displayed and represented on a digital display device. A pixel is the basic logical unit in digital graphics. Pixels are combined to form a complete image, video, text, or any visible thing on a computer display

LCD display doesn’t operate the same way as CRT displays , which fires electrons at a glass screen, a LCD display has individual pixels arranged in a rectangular grid. Each pixel has RGB(Red, Green, Blue) sub-pixel that can be turned on or off. When all of a pixel’s sub-pixels are turned off, it appears black. When all the sub-pixels are turned on 100%, it appears white. By adjusting the individual levels of red, green, and blue light, millions of color combinations are possible

Fig.1 LCD Pixel With RGB Sub-pixels

The pixels of the LCD screen were made by circuitry and electrodes of the backplane. Each sub-pixel contains a TFT (Thin Film Transistor) element.  These structures are formed by depositing various materials (metals and silicon) on to the glass substrate that will become one part of the complete display “stack,” and then making them through photolithography. For more information about TFT LCDs, please refer to “An Overview of The Thin Film Transistor And Its Use in Displays “.

The etched pixels by photolith process are the Native Resolution. Actually, all the flat panel displays, LCD, OLED, Plasma etc.) have native resolution which are different from CRT monitors

HD TV has 1280×720 = 921,600 pixels; Full HD has 1920x 1080=2,073,600 pixels; 8K TV has 7,680×4,320=33,177,600 pixels. he “K” in 8K stands for Kilo (1000), meaning a TV that has achieved a horizonal resolution of about 8,000 pixels.

 

What Is DPI / PPI?

Although we can define a LCD display with resolution, a Full HD resolution on screen size of a 15” monitor or a 27” monitor will show different. The screen “fineness” is very important for some application, like medical, or even our cell phone. If the display “fineness” is not enough, the display will look “pixelized” which is unable to show details.

Fig.2 Pixelized Bug Shown After Zoom In

How we can define the “Fineness” of a LCD display ?

A lot of times, we heard about what is the DPI of your monitor, actually it is not a exact correct saying. Please find the definition of DPI and PPI as below.

DPI stands for dots per inch and refers to the resolution of a printer. It describes the density of ink dots placed on a sheet of paper (or another photographic medium) by a printer to create a physical print.

PPI stands for number of pixels per inch. It is kind of pixel density. PPI describes the resolution of a digital image, not a print. PPI is used to resize images in preparation for printing

Now, we are clear about the confusion.

 

How do you read the display resolution of my LCD monitor or laptop?

It is easy to find on your laptop. Simply find display setting in your control panel. The highest resolution shown is your native resolution.

Fig.3 My Laptop Screen has Native Resolution of 1920 x 1200

 

But you see other lower resolution available, that is because video cards are doing the trick. A video card can display a lower LCD screen resolution than the LCD’s built-in native resolution. The video cards can combine the pixels and turn a higher resolution into lower resolution, or just use part of the full screen. But video cards can’t do the magic to exceed the native resolution.

What resolution is 1024×768? What is 1920×1080 resolution?

You might hear a lot of ways to describe a LCD screen properties. That depends on what characteristic or function you focus on.

  • Resolution:  1024×768, 1920×1080 etc. This is very straightforward but difficult to remember.
  • Abbreviation: QVGA, VGA, HD, FHD, 1080p, 1440p, 4K etc. It is very straight forward for different applications. For TV buyers, they can simply focus on 4K, 8K etc; for industrial engineers, they most likely focus on VGA, HD, WVGA etc.
  • Aspect Ratio:  You might hear 4:3 which is full screen, 16:9 is for widescreen; 21:9 is for ultrawide computer monitors and televisions, as well as cinematic widescreen projectors. Some ultrawide monitors are trying to replace dual monitor.

Fig.4 Ultrawide vs Dual Monitors

  • Special names by individual companies: Apple Macbook Pro Retina 6K display, Acer Nitro, ASUS Pro Art , ViewSonic Elite, ASUS TUF ,Samsung edge Infinity-O Display etc.

 

LCD Screen Resolution Chart

LCD Standard LCD Pixels LCD Term
SQCIF 128 x 96 Sub CIF
QCIF 176 x 144 Quarter CIF
CGA 320 x 200 Color Graphics Adapter
QVGA 320 x 240 Quarter VGA
CIF 352 x 288 Common Intermediate Format
WQVGA 400 x 240 Wide QVGA
EGA 640 x 350 Extended-Graphics-Adapter
VGA 640 x 480 Video Graphics Array
WVGA 800 x 480 Wide VGA
SVGA 800 x 600 Super VGA
XGA 1024 x 768 Extended Graphics Array
HD 1280 x720 HD, High Definition
XVGA 1280 x 960 Extended Video Graphics Array
SXGA 1280 x 1024 Super SGA
SXGA+ 1400 x 1050 Super eXtended VGA plus
SXGA-W 1600 x 1024
UXGA 1600 x 1200 Ultra XGA
WXGA 1366 x 768 Wide XGA
WSXGA 1680 x 1050
1080p 1920 x1080 Full HD
WUXGA 1920 x 1200 Widescreen Ultra XGA
QXGA 2048 x 1536 Quad Extended Graphics Array
WQXGA 2560 x 1600
QSXGA 2560 x 2048
2K 2,048x[unspecified]
4K 3,840×2,160 Ultra HD
8K 7,680×4,320 8K UHD