How to produce the Liquid Crystal Display(LCD) (3)- Backlight to Inspection

Step 10: Assemble BL

Before working:

• Check the FOG, whether it as broken, has rift .
• Check the polarize has prick and rough
• Whether the Ionizing air blower is working normally

Check whether it is well assembled and has broken corner.

Operation procedure

• Under the Ionizing air blower, pick the BL with thumb and index finger of the left hand ,take glass with index finger and middle finger, use right hand to peer protective film .
• Peer BL from the side with ear, glass from the side of ITO, which must be operated in the effective distance of Ionizing air blower
• After peering, check under strong light , whether there are some abnormal, if yes, wipe with cotton buds by right hand .
• Assemble after checking The positon between eyes and assemble must be 20-30cm
• Assemble according to the alignment of glass ITO
• Assemble criterion: according to the BL ,assemble in the middle After assemble, press the four corner of LCD to make sure there is no float
• Well assembled the OLB and BL without rift

Operation procedure:

• Under the Ionizing air blower, pick the BL with thumb and index finger of the left hand ,take glass with index finger and middle finger, use right hand to peer protective film.
• Peer BL from the side with ear, glass from the side of ITO, which must be operated in the effective distance of Ionizing air blower
• After peering, check under strong light , whether there are some abnormal, if yes, wipe with cotton buds by right hand .
• Assemble after checking The positon between eyes and assemble must be 20-30cm
• Assemble according to the alignment of glass ITO
• Assemble criterion: according to the BL ,assemble in the middle After assemble, press the four corner of LCD to make sure there is no float
• Well assembled the OLB and BL without rift

Attention :

• Peer the protective film from the side of ear of BL The direction of Ionizing air blower and peer the protective film should be at the same plane to avoid the dust
• Make sure the effectiveness of Ionizing air blower, working in the distance of 20cm of Ionizing air blower, avoid missing peering the protective film
• When peering the film, the speed should be controlled over 3 s, to avoid the static electricity, avoid touching the display area of LCD
• Clean the dust and dirt, using cotton swab to dip alcohol and clean .
• It is the same with BL

Processing Method : If there is something abnormal, pls inform technical, monitor and so on .

Step 11: Backlight assemble

Step 12: Easy tear stick attach

• Check before operation
• Incoming Quality Control (IQC)
• If there is broken corner of lcd

Description:

• To make sure that the tft version is the same with the tft to be manufactured.
• Folded the easy tear stick in half, take one tft with hand.
• Press the product between the fingers of your left hand. tore a easy tear stick Right hand, with paste parts sticking alignment LCD aligned with the above, with the thumb press the right edge of the LCD can make easy tear stick in hand to tear up the protective film
• Put attached tft in blister boxes tidily

Note:

• TFT needs to be put into next procedure separately if various tft are being manufactured.
• To check if the easy stear stick are being attached slantly.
• To check if the protect film could be teared up easily.
• To check if there is levels off after operation

Step 13: Backlight welding

Check before operation: the temperature is between 320 and 350C for the soldering iron

Description:

• To check if the instruments are put in right order.
• To check if the tft are distinguished with number.
• To check if the tfts are broken.
• Taking anti-static measures and make sure the antistatic figure cot and bracelet and ready before operation.
• To check the temperature of the electric soldering iron before the operation, usually between 320 to 350 degree centigrade.
• With electric soldering iron in your right hand and tin wire in your left hand, put the tin wire in the bonding pad well then heating soldering iron to weld, soldering iron fall down to the solder joint.
• The welding have to be rechecked by operator to see if there are defects in welding such as cold solder missing solder or short solder.
• The tft could only be sent to next operation after they are welded perfectly.

Note:

• Be cautious when using iron soldering iron case you are burned.
• To prevent the iron from being oxide, pls cover the iron Nozzles with tin when it is not in use.
• Handle the tft with care when you take it.
• As there might be dross in your finger when you are solidering tin( lead might be part of it), wash your hands before duty close in case it might be harmful to your health.
• In case the hot solder paste splashes and hurt other people around, it is nor allowed to shake or bump the solidering iron to clear aging tin. The correct method should be using the Wet sponge to clear the iron Nozzles.
• Mesa of solder has to be cleared two hours a time. The clean method is : the first step is to put the mesa of tin slag in a special bag, then put the tin slag and other dirt to special bag with the clean cloth dipped in alcohol cleaning should be self-checking and to make sure it is okay.
• Tin slag in the iron frame should be cleaned once a week.

Temperature bias:

• To check if there is oxid in the bond pad.
• To check if there is off position with pin soldered.

Step 14: Check/Test the Display again

Description:

• To make sure if the rotating disk are put in number
• To make sure if staff are put in order, engineer should confirm for special spec.
• To check if there are defects such as burned tft, Leakage liquid crystal ,dirty or foreign matter.
• Clean the working table, choose different demo board for different tft type.
• Put the orthobaric FOG into the demo board, Align the PCB pin with FPC pin, press the mound layer And pree the button of Start and pictures separatly.
• Electrical line defects (such as horizontal, vertical, horizontal and vertical defect etc.) light-leaking, cilia, foreign matter.
• Line defacte(Bright point/black spots)
• If RGB pixel is complete
• Electrical line defects (such as horizontal, vertical, horizontal and vertical defect etc.)
• Spot or line defect, Bubbles, scratches and foreign matter
• Image uniformity
• Checking the image in person is to make color contrast and to check if there is jamming signal.

Note:

• Please notice the mistake order and inform the other department to improve.
• Inform PE personnel immediately when there is test tool malfunction
• Complete process card correctly, flow in sequence
• Make the first confirm according to ROM table, work order, samples, check product VOP, and telecommunications
• Inform the monitor technological personnel when ther are defect or overweight
• In order to prevent the defect from other defect, it should be placed separately and should not be throw away.
• The test table should be ready for test.
• To make sure that the electric-free appliance are ready and in good working condition when operating, the appliance should face toward the area where human and product contact.

After working: to check if there is burn, LCD leakage, collapse angle, or dirty foreign matter defect.

Step 15: High temperature tape attach

Operating steps:

• Place the product to be tested horizontally on workbench.
• Take a piece of high temperature tape with Nipper to attch fully on the Solder joint parts.
• Completely cover the Solder joint parts.
• Put the attched product on the plastic tray orderly.

Attentions:

• Checking previous process items,any defective product, it will be noticed and corrected.
• Any break on ITO,we will distinguish from it.
• Don’t cover FPC’s bonding pad localization hole.
• Checking whether it covers bonding pad completely.
• Edge of high temperature tape can’t exceed FPC’s edge,edge up and other undesirable effects.
• Attached item can’t pile up.

Stpe 16: Appearance checking

Checking whether there is any appearance badness of the overall product.( Checking previous process items,any defective product, it will be noticed and corrected)

Operating steps:

• Picking up both side of the product in hand and checking the apperance of the item according to quality spec requirments in positive visua.
• Picking up the defective product in previous process.non-defective product need to place orderly on plastic tray.

Attention:

1. Bubbles on polarizer,white dot,concave and convex dot,scratches,glue on the polarizer,Askew phenomenon.
2. Assembly skew, don’t reach the designated position.
3. High temperature solder, offset, false welding phenomenon.
4. Checking whether there is missing label and askew phenomenon.
5. Checking whether the whole product’s model,label,spec and code are agreed.