Chip-On-Glass(COG) LCD Display vs Chip-On-Board (COB) LCD Display

COG LCD Display Module vs COB LCD Display Module

Unlike typical LCD modules, COG displays are designed without a PCB. Instead, the LCD's driver/controller is directly bonded to the glass of the display. This allows COG displays to be smaller in size, more cost effective and a highly customizable display solution compared to typical LCD modules.


COG Displays

COG LCDs are composed of two pieces of polarized glass. On the non-polarized side of the glass, a special polymer is added to create grooves that run in the same direction as the polarizing film. Once this is done, a liquid crystal material is added to the grooved side of one of the polarized glasses. These grooves align the liquid crystal with the glass. The second piece of glass is placed on top with the grooved side in, aligned perpendicular to the first pieces of glass creating a row and column arrangement. The LCD driver/controller is then mounted directly to the LCD glass by bonding the gold bumps of the IC to the indium tin oxide (ITO) tracks on the glass.

COG Unique Features

  • 5x8 dot matrix characters or monochrome graphics with custom icons

  • Low power but high brightness

  • No bezel for profiles as thin as 2mm

  • Character COGs have 4 font tables

  • Particularly cost effective

Graphic COB LCD Displays
Graphic LCD modules come in STN and FSTN types that come in a wide variety of sizes measured in pixel width-by-height dimensions (i.e. 240x128 meaning 240 pixels wide by 128 pixels tall). Our standard LCD graphic displays are passive matrix modules.
They use a dot matrix pattern to display both text and simple bitmap images. They are capable of more complex images than that of a character display, but require much more information to do so since they need to be told what do to with each pixel in their matrix.

Character COB LCDs

Our character LCD modules are monochrome, passive matrix displays with pre-programmed font tables built-in. They come in standard sizes in either STN or FSTN types, from 1 line x 8 characters, to 4 lines x 40 characters.

Character displays display simple text from forms in their built-in font tables. Each display has at least one row with a number of “characters”. Each of these characters is a cell that can be filled with the user’s choice of form from the programmed font table; for example you might want row 1, cell 1 to contain a capital roman “A”.