|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
COG & TAB
COG (chip-on-glass) and TAB (tape automatic bonding) LCD displays take less space, use less electrical current, and have higher reliability. Most COG and and TAB LCD units are custom made. COG and TAB are commonly applied for computer, telephone and guidance screens. Their versatility has proven to be a valuable asset in creating high-accuracy alignment levels for multi-chip modules (MCM), compound devices, and LCD displays. Standard MCM applications such as automotive electronics and computers as well as COG applications for watches, telephones and other read-out displays have been largely perfected with current flip chip technology.
CHIP-ON-GLASS (COG)
Chip-on-glass is one of the high-tech mounting methods that uses Gold Bump or Flip Chip ICs and implemented in most compact applications. COG 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 the required size of the PCB. This technology reduces a mounting area and is better suited to handling high-speed or high-frequency signals. Currently, there are 12 standard COG LCD modules available with the regular mass production delivery time.
COG ADVANTAGES
* Very space-economical; COG LCD modules can be as thin as 2 mm.
* COG is more cost-effective over COB especially in graphic LCD modules because far fewer ICs are required.
* COG is more reliable than TAB because of the weakness in the TAB bond area.
COG DISADVANTAGES
* 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 would then be 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 of a COG is not centered within the outline but, instead, offset because of the area where the circuits are located.
* Since the chip-on-glass integrated circuit was invented by Epson, COG technology became very popular due to the demand for more compact applications. In the near future this IC mounting method will begin to be applied in many other types of equipment other than cellular phones, PDAs, computer network servers, satellite receivers, etc.
TAPE AUTOMATED BONDING (TAB)
Tape Automated Bonding (TAB) LCD driver or controller electronics are encapsulated in a thin, hard bubble package in which the drive leads extend from the bubble package on a thin plastic substrate. The adhesive along the edges is used to attach the TAB to the LCD glass and/or PCB.
TAB IC mounting method uses the same type of integrated circuits as COG technology - Gold Bumped Flip Chips. After this type IC chip has been produced, a gold bump is placed on the IC chip and then sealed onto the polymide board. This procedure is called Inner Lead Bonding (ILB) and is how the TCP IC is produced. TAB LCD modules are always custom made.
TAB ADVANTAGES
* TAB offers compactness as IC and its interfacing circuitry can be bent behind the LCD glass panel.
* TAB is sometimes more cost-effective than COG if a designer has to integrate a keypad or indicator around the display.
* Unlike COG, the active area for TAB is centered.
* Interfacing at very fine pitches can be provided by TAB.
TAB DISADVANTAGES
* The bonding area is weak and less reliable than COG.
* TAB is more expensive than COG. Even though TAB LCD modules use the same type of IC as COG, tape automated bonding requires a package.
The list of available items in this category can be seen on the GEI LCD COG & TAB page.
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
CSTN
CSTN (color super twist nematic) is a type of display technology used in older handheld and palm-sized computers. This technology is also common in liquid crystal displays (LCDs). Another name for CSTN is single-layer super twist nematic. Consumer electronics, telecom products, and industrial equipment applications keep the CSTN LCD module segment steady as TFT dominates large-sized display applications.
The list of available items in this category can be seen on the GEI LCD CSTN page.
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
TFT
TFT (Thin Film Transistor-Liquid Crystal Display) is a variant of Liquid Crystal Display (LCD) which uses Thin-Film Transistor (TFT) technology to improve image quality. TFT LCDs are one type of active matrix LCD, though this is usually synonymous with them. They are used in both flat panel displays and projectors.
In computing, TFT monitors are rapidly displacing competing CRT technology and are commonly available in sizes from 12 to 30 inches. As of 2006, they have also made inroads on the television market.
The list of available items in this category can be seen on the GEI LCD TFT page.
|
