FOG bonding and COG bonding are two different methods used in the manufacturing of displays, particularly LCDs (Liquid Crystal Displays). While both methods involve bonding a flexible printed circuit (FPC) onto a glass substrate, there are some key differences between FOG bonding and COG bonding.
Definition:
FOG Bonding (Film On Glass): FOG bonding refers to the process of mechanically fixing and conductively bonding an FPC onto a glass substrate [1].
COG Bonding (Chip On Glass): COG bonding involves directly bonding the driver IC (Integrated Circuit) onto the glass substrate of the display [1].
Bonding Method:
FOG Bonding: In FOG bonding, the FPC is mechanically fixed and conductively bonded to the glass substrate using an adhesive, such as anisotropic conductive film (ACF) .
COG Bonding: In COG bonding, the driver IC is directly bonded onto the glass substrate using a thermal crimping process with ACF .
Purpose:
FOG Bonding: FOG bonding is primarily used to bond the FPC onto the glass substrate, providing the necessary electrical connections for driving the display .
COG Bonding: COG bonding is used to directly bond the driver IC onto the glass substrate, eliminating the need for a separate PCB (Printed Circuit Board) .
Advantages and Disadvantages:
FOG Bonding:
Advantages: FOG bonding allows for a narrow frame display, as the driver bonding can be done on the FPC, reducing the overall frame size . It also provides flexibility in design and allows for easier mass production .
Disadvantages: FOG bonding may require additional components and assembly steps compared to COG bonding .
COG Bonding:
Advantages: COG bonding reduces the size and weight of the display module, as the driver IC is directly bonded onto the glass substrate . It also simplifies the manufacturing process by eliminating the need for a separate PCB .
Disadvantages: COG bonding may limit design flexibility, as the driver IC is directly bonded onto the glass substrate . It may also require more precise alignment during the bonding process .
