Chip-On-Glass – is one of the high-tech mounting methods that
uses Gold Bump or Flip Chip IC’s, and implemented in most compact
applications. Chip-On-Glass integrated circuits were first introduced
by Epson. In flip-chip mounting, the IC chip is not packaged but is
mounted directly onto the PCB as a bare chip. Because there is no
package, the mounted footprint of the IC can be minimized, along with
size of the PCB. This technology reduces a mounting area and is better
suited to handling high-speed or high-frequency signals.
Very space economical. Chip-On-Glass LCD modules can be as thin
as 2 mm.
Cost effective over COB, especially in graphic LCD modules, because
much less IC's are required.
More reliable than TAB because of the weakness in the bond area
COG can only be used at a certain resolution level where the lines
are not too fine. At very fine pitches COG becomes difficult to
test, and TAB is the preferred approach.
It may be more cost-effective to use TAB or COB, if a designer has
to integrate a keypad or indicator around the display.
The active area is not centered within the outline but offset, because
of the area where the circuits are.
Since the Chip-On-Glass integrated circuit has been invented by
Epson, COG technology became very popular due to the demand for
more compact applications. In the near future we will see this IC
mounting method finding its applications in many other equipment
than cellular phones, PDA's, computer network servers, satellite