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The manufacturing process flow of the LCD display screen in china

Process flow Description:

 

Front station:

 

The injection of ITO glass -- glass CLEANING and drying -- PR COAT -- PREBREAK -- DEVELOP MAIN CURE -- ETCHING -- STRIP CLEAN -- TOP COAT -- UV CURE -- curing -- MANICURE) - cleaning (CLEAN) - applied orientation agent (PI) PRINT - CURING (MAIN CURE), cleaning (CLEAN), silk screen printing (SEAL/SHORT PRINTING) - baking (CUPPING FURNACE), SPRAY packing material (SPACER SPRAY) - para pressing (ASSEMBLY) - CURING (SEAL MAIN CURING)

 

 

1.Etch of ITO pattern :(input of ITO glass into graph inspection is completed)

 

A.The input of ITO glass: According to the requirements of the product, appropriate ITO glass is selected and put into the transfer basket. Specifications and models of ITO glass are required to meet the requirements of the product. Remember that the ITO layer must be inserted into the basket upward.

 

B. Cleaning and drying of glass: Clean ITO glass with the cleaning agent and deionized water (DI water), wash impurities and oil stains on the ITO surface with physical or chemical methods, and then remove and dry the water to ensure the processing quality of the next process.

 

C.Photoresist coating: Evenly coat a layer of photoresist on the conductive surface of ITO glass. The glass coated with photoresist must be pretreated at a certain temperature: (as shown in the figure below)

 

D.Pre-drying: The glass coated with photoresist is baked for a period of time at a certain temperature to volatilize the solvent in the photoresist and increase its adhesion to the glass surface.

 

E.Exposure: Ultraviolet light (UV) is used to illuminate the surface of the photoresist through the pre-made electrode pattern mask, which causes the reaction of the photoresist layer. The photoresist is selectively exposed under an ultraviolet lamp by covering the photoresist on the glass coated with photoresist (as shown in the figure).

 

F.Development: the surface of the glass is treated with developer solution, the photoresist layer decomposed by light is removed, the photoresist layer of the unexposed part is retained, the photoresist of the part exposed by UV light is dissolved in the developer solution by chemical method, the developed glass has to undergo a certain temperature hardening film treatment.

 

G.Tough film: the glass will be processed by high temperature again, making the photoresist stronger.

 

H.Etching: With appropriate acid etching solution, the ITO film without photoresist covering is etched off. Thus, the required ITO electrode pattern is obtained.

 

Note: ITO glass is conductive glass (In2O3 and SnO2), which is easy to react with acid and used to etch off the excess ITO to obtain the corresponding wire electrode.

 

I.Film removal: the high concentration of alkali solution (NaOH solution) is used as the film removal solution to peel off the remaining photoresist on the glass, thus forming ITO graphics exactly consistent with the lithography mask on the ITO glass.

 

J.Cleaning and drying: Rinse remaining lye and remaining photoresist and other impurities with high purity water.

 

 

2. Special process :(TOP film coating until curing and cleaning)

 

General TN and the STN product does not require this step, the TOP film coating process is after the photolithography process making SiO2 coating, once again to the etching area and the etching area between the grooved bridge and the electrode covering, this can have the effect of the insulation layer, and can effectively eliminate the display state of the bottom electrode, also help to improve the perspective characteristics and so on, so most of the high-grade product requires TOP coating.

 

 

3.Orientation coating (until cleaning is complete)

 

This process involves coating an oriented layer on the etched ITO glass surface and treating the restricted layer in a specific way so that the liquid crystal molecules can be oriented (arranged) in a specific direction on the surface of the oriented layer. This step is unique to the production of liquid crystal displays.

 

A.Orientation coating agent:

 

Organic polymer oriented material is coated on the surface of the glass, that is, a uniform orientation layer is applied to the appropriate position of ITO glass by a selective coating method, and the orientation layer is cured at the same time. (Usually in the display area)

 

B.Curing:

 

The orientation layer is cured by high-temperature treatment.

 

C.Oriented friction:

 

Flannelette material is used to rub the surface of the oriented layer in a specific direction so that the liquid crystal molecules can be arranged along the friction direction of the oriented layer in the future. For example, TN type friction orientation: 45 degrees

 

D.Cleaning:

 

Contaminants such as flannelette thread will be left on the rubbed glass. Special cleaning steps are required to eliminate the contaminants.

 

 

4. Empty box production :(screen printing to curing)

 

In this process, two conductive glasses are stacked on top of each other, and sealed together and cured to make a glass box with a specific thickness of clearance. The technology of box - making is one of the key technologies in LCD manufacturing. (Spacing of LIQUID crystal boxes must be strictly controlled)

 

A.Silk-screen printing frame and silver spot:

 

the sealing material (frame sealant) is used to screen printing on the upper plate and the lower plate glass printing is a conductive adhesive.

 

B.Gasket spray:

 

Evenly distribute the supporting material over the lower glass. A certain size of the liner (usually a few microns) is evenly distributed over the surface of the glass. These materials are used to ensure that the spacing between the glasses is the thickness of the box.

 

C.Counterpressing:

 

press the upper and lower glass against each other on the counterpoint mark, and then glue the corresponding two pieces of glass face to face with sealing material.

 

D.Curing:

 

Curing the sealing material at high temperatures. When curing, the pressure is applied to the upper and lower glass to make the spacing of the liquid crystal boxes (thickness remains uniform).

 

 

Rear station:

 

SCRIBING -- BREAK OFF -- LC INJECTION -- END seal -- BREAK OFF -- sharpen -- VISUAL inspection -- ELECTRICAL test -- secondary cleaning special procedure (POLYGON) -- BACK PRINTING -- dry ink -- POLARIZER ASSEMBLY -- Thermal pressure -- Inspection appearance test (FQC) -- BIT PIN -- FINAL test -- PACKING -- IN STOCK.

 

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