Overview of LCM process

The LCM manufacturing process is to choose the appropriate processing method according to different design requirements, for liquid crystal display (LCD) with the drive circuit, causes it to have certain display function of liquid crystal display module (LCM). According to the driving circuit part of the processing method and Realization of screen and a driving part is connected to the LCM, the manufacturing process can be divided into the following categories:

The SMT process, COB process, HS process, assembly process, TAB process, COG process.

In the process, the SMT and COB technology is used for the LCM driver circuit processing, they can be said to be the whole LCM process before processing; and HS processing and assembly process is the second part of the overall LCM process, these two kinds of technology is based on the screen and driving circuit some of the different ways of connection, the screen is connected with the drive to different processing, to produce LCM products. TAB and COG technology is a new processing technology in recent years, after processing can be any one of these two kinds of technology in the process of manufacturing LCM products.

1 Introduction to the process

(1) SMT process:
SMT is Surface Mounted Technology English abbreviation, Chinese translation for surface mount technology.
SMT is the process of liquid crystal display driver circuit board (PCB board) is one of the manufacturing process, it is used to mount equipment will mount components (resistors, capacitors, chip) attached to the printed PCB board solder pads on the corresponding position, and the return device and a processing method of components on the PCB board welding the.
The process includes printing, placement, reflow, cleaning and detecting five processes. SMT process due to mount components (especially chip size (size) package), effect of chip pin clearance number and equipment precision machining, which is suitable for large area of the PCB board, and because of the solder joint is exposed, vulnerable to damage, but easy to repair.

(2) COB process:
COB is Chip On Board English shorthand, it is another way of processing LCM drive circuit board.
This is the process of the bare chip with adhesive directly attached to the PCB board on the specified position, the chip power through welding machine with aluminum
Electrical and mechanical connection between the. The process includes adhesive, curing, welding, testing, sealing glue, curing process and test seven.
The COB process uses a small bare chip, high precision machining equipment, the line number PCB plate more, thinner, smaller gap area, sealing protection chip welding with black adhesive, solder joint and the welding line is not affected by external damage, the reliability is high, but the damage can not be repaired, can only be scrapped.

(3) HS process:
HS is a Heat Seal English abbreviation, Chinese translation for hot pressing process. It is with zebra paper through hot pressing equipment in a certain period of time, temperature and pressure. Pressure, heating, and connect the screen and PCB plate electrode, so as to screen and drive a processing circuit part in mechanical and electrical connection to the. The process includes screen, check, hot pressing, hot plate test four processes.

(4) the assembly process:
The assembly process is through the conductive strip (zebra) or metal pins to connect the screen and PCB plate electrode, so as to realize the screen and PCB in the mechanical and electrical connection of a processing method for the conductive connection assembly, the process including shell, screen, put put put, conductive rubber strip PCB plate, screw, seven legs and detection process. For the selection of metal pins to achieve assembly by welding connection, because in the process of LCM, the metal pins have been fixed on the LCD screen on the outside, so the process including plaque, welding, scissors, cleaning and detection of the five processes. The assembly process using conductive rubber strip is connected with the PCB plate, the screen electrode on the back, when the LCD screen electrode of COM or SEG with one or at the same time the screen is generally positive when using hot, hot pressing or side, the other side is connected to the screen and the PCB board with conductive connection of course, these special circumstances can also use special conductive materials to achieve the connection, but the cost is higher.

(5) the TAB and COG technology:
TAB is Tape Automated Bonding English shorthand, it is soft with a drive circuit through the ACF (anisotropic conductive film bonding), a realization of the screen and driving circuit board connected with the processing method and hot pressing at a certain temperature, pressure and time. It mainly includes the ACF preloading, on examination, main pressure and detection of four processes.

COG is Chip On Glass English abbreviation, is a processing method of LCD and IC circuit directly connected together, it is designed in the LCD concentration leads to very small area on LCD dedicated LSI-IC chip bonding in the meantime, with the pressure of each endpoint in accordance with the requirements of wire welded together, and then cast a drops of sealing in the above can be dropped, and the input end of the IC is also designed in the LCD lead glass, and the input end as pressure welding to the chip, the chip LCD, this has already formed a complete LCD module, as long as the hot pressing its and PCB together can be a. The process mainly includes on screen, ACF, chip, chip alignment check, pressure welding, sealing glue, detection of seven processes.

2 the process characteristics

(1) SMT and COB technology:
Compared with the SMT and COB process, SMT process due to mount components (especially chip size (size) package), effect of chip pin clearance number and equipment precision machining, which is suitable for large area of PCB board, and because of the solder joint is exposed, vulnerable to damage, but easy to repair. COB technology is the core of small nude