Positive and Negative Mode LCD Display


An Overview of Positive and Negative Mode LCD Displays

LCD (Liquid Crystal Displays) have two options or display modes. Positive mode (dark characters on a light colored background) and negative mode (lighter colored characters on a darker background). Please see Fig.1. Yellow green STN (Super Twisted Nematic) display, the background of yellow green is lighter than dark blue characters. It is positive mode. Fig. 2 is blue STN display, its background of blue is darker than the white characters. It is negative mode.

 

Fig. 1 Yellow Green STN LCD (Positive Mode)

 

 

Fig. 2 Blue STN LCD (Negative Mode)

Positive Mode LCDs

Positive mode displays have the advantage of their lighter background and no backlights are needed. They normally use transflective or reflective polarizers and have lower power consumption. They can be seen with ambient light.

Negative Mode LCDs

Negative mode displays need backlit in order to be seen. They normally use transmissive polarizers. They have better contrast and wider viewing angles in the indoor dim environment. The readability is much better than positive displays. But under bright ambient light or even under direct sunlight, the displays will be easily washed out. In order to be seen under the bright surrounding light, the backlight brightness has to be increased to over 800 nits. The sunlight readable displays consume much power.

 

Which is better, Positive or Negative LCDs?

That depends your application.

You can choose Positive LCDs if you are looking for:

  • Low cost;
  • Low power consumption with battery as main power resources;
  • Used in outdoor or bright ambient light.

You can choose Negative LCDs if you are looking for:

  • Used indoor or low light environment;
  • Sharp or catching images or contrast with better viewing angles;
  • Night vision with green or black background, such as aviation panels, bedside alarm clock etc.

 

Of course, we can always use LED backlight in the LCD module with fewer LED chips and turn off LED backlight when not use to save power. When can also add transflective polarizer to some negative LCDs to make it sunlight readable but the contrast will be compromised.

Positive and negative mode concept is not only limited to monochrome LCD display (LCD panels, character LCDs, graphic LCDs etc.), it also uses for color displays, or even other display technologies.  We will categorize the displays as below,

 

Positive Displays:

  • Positive TN LCDs
  • HTN LCDs
  • Yellow Green STN LCDs
  • Gray STN LCDs
  • Positive FSTN LCDs

Negative Displays:

  • Negative TN LCDs
  • Blue STN LCDs
  • Negative FSTN (Film Compensated STN) LCDs
  • VTN (Vertical Alignment or VA) LCDs
  • FFSTN (Double Film FSTN) LCDs
  • TFT (Thin Film Transistor) LCDs
  • IPS ( In-Plane-Switching) LCDs
  • AFFS ( Advanced Fringe Field Switching) LCDs
  • OLED Displays including PMOLED (Passive Matrix Organic Light Emitting Diode) and AMOLED (Active Matrix Organic Light Emitting Diode)

Orient Display offers all the products mentioned above:

  • LCD glass panels with the number of digits from 1 to 8 and 7 segment LCD display, 14 segment LCD display, 16 segment LCD displays

 

  • Character LCD modules (Alphanumeric LCD display modules) with character sets: 8×1 LCD display, 8×2 LCD display, 16×1 LCD display, 16×2 LCD display, 16×4 LCD display, 20×2 LCD display, 20×4 LCD display, 24×2 LCD display, 40×2 LCD display, 40×4 LCD display. COB (Chip on Board) bonded, 4 or 8 bits parallel, SPI, I2C interface

 

  • Graphic LCD modules with dot matrix sets 122×32, graphic LCD display, 128×64 graphic LCD display, 192×48 graphic LCD display,192×64 graphic LCD display,240×64 graphic LCD display,240×128 graphic LCD display,240×160 graphic LCD display with different color LED backlights, with COB and COG (Chip on Glass) assembling technologies

 

  • Monochrome and Color Graphic OLED modules with dot matrix sets 128×32 graphic OLED display,128×64 graphic OLED display, 128×96 graphic OLED display, 160×128 graphic OLED display, 128×128 graphic OLED display, 256×65 graphic OLED display

 

  • Full Color TN and IPS displays with panel sizes: 1.3”IPS display, 1.44” TN display, 1.5” IPS display, 1.77”TN and IPS displays, 2.0” TN and IPS displays, 2.2” IPS display, 2.35” IPS display, 2.4” TN and IPS displays, 2.8” TN and IPS displays, 3.5” TN and IPS displays, 4.3” TN display, 5.0” TN and IPS display, 7.0” TN and IPS display, 10.1” IPS display with medium and high brightness (sunlight readable), with parallel, SPI, RGB, LVDS, MIPI interfaces.