Good Evening All , Today in this blog post , i am going to unravel the answer to one baffling question , i have been asked many times by our stuents, our clients and many companies to whom CHIPTRONIKS provides consultancy .

Can LCD Screen be repaired if its not physically broken ? And we gave the answer “yes” . Finally after 1 year of research , CHIPTRONIKS now possess the technology of repairng LCD screens of Laptops/mobiles/LCD television , and we are soon going to lauch a full fledged 10,000 clean room fro repairing lcd screens.

Now let us understand how it works : I will give some glimpse of this , and if any body wants to start LCD screen repairing business, CHIPTRONIKS can offer consultancy in this :

Let us understand first :

Main Components of LCD screen :

•TFT/LCD Glass Substrate
• Polarizer Film
• Gate PCB
• Gate IC Driver
• Source PCB
• Source Driver IC
• Interface Connector (Flex
Cable)
• Backlit Inverter
• CCF Lamp
• Diffuser,Lens Sheet,
• Light guide,Reflector Sheet

Machines Required for LCD Screen Repairing:

1. Bonding Machine
2. Laminator
3.De-Laminator
4.Line Tester
5. LCD Panel Tester
6. Ionising Bar & Blow off Gun
7. Aging Test Chamber
8. Zero Clean Laminate Box
9. Clean Air Booths- Triple Boot
10. IC Driver Rework System
11.Test Tables
12. Color Analyzer
13. Polarizer Film Surface Detector

Concepts to Understand:

1. What is LCd Panel ?
2. What are major LCD Panel defects ?
3. What is cleanroom ?
4. What is an IC driver and its types  ?
5. What is Polarizer film ?
6. Optical measurement of a LCD Panel ?
7. What is ACF ?
8. How to use ACF ?
9. How to test LCD panels ?

What can be repaired? 

LCD Panel repair :
– Polarizer film replacement
– TAB,COG,COF bonding
– Backlight and LED repair
PCB repair
– Gate PCB repair
– Source PCB repair
LCD Display Repair

Main Points :

(a) Polarizer Film Replacement

The replacement of LCD Panel process consist of below stages;
– Disassembly of LCD Panel
– Detaching glass substrate from the panel and metal frame
– Removal of polarizer film (delaminating)
– Cleaning (using special chemicals) of glass substrate to the reapplication of the
new polarizing film
– Replacing polarizer film (laminating)
– Color Analyzer for optical test
• Removal and replacement of polarizing film need to be conducted
under stringent antistatic conditions (clean room environment).
• Panels placed in antistatic plastic bags.

(b)TAB,COF and COG Bonding

• The most common IC mounting methods are TAB,COF and COG.
• IC drivers provide the required current voltage needed to turn power
switching elements on and off.
• Horizontal or Vertical Lines on the screen are common failures caused by
failing driver IC’s and poor bonding to the conductive traces on the glass
substrate.

(C) Bonding Process

The purpose of the bonding is to replace the defect IC driver from
the PCB and the LCD glass substrate.
• IC driver will be demounted from the LCD glass and the PCB.
• Connectors will be cleaned and examined under the microscope.
• LCD Panel will be checked by the ITO tester to find out if there is
an IC driver defect or an ITO line defect.
• If there is an IC driver defect, the IC driver bonding process starts
and new IC driver will be bonded on the LCD glass and PCB
connectors.

(D) BLU

The most common BLU related defects are;
– Diffuser sheet
– CCFL Lamp and LED
– Reflector sheet
– Light guide