LED and LCD Panel Training

Training Manual of Panel(CCFL & LED)

CCFL Lamps Appearance

U-shapes lamps

straight lampsM-shapes lamps

Inverter Board

Power supply voltage board and inverter board is one PCB

Inverter board

TFT-LCD Imaging Principle1:Scan IC transmission signal

2:Driver IC transmission imaging control signal

3:When one sub-pixel cut-off, the sub-pixel cannot get light to show black.

4:If sub-pixel cut-off ,but light through the color filter and display color

5:After the synthesis of light effects, the display can produce color effects.

Color filterenlarge

TFT-LCD Imaging Principle

TFT-LCD Imaging Principle

CCFL backlight LCD TV

4unit CCFL small size LCD TV

Lots of CCFL big size LCD TV

CCFL is not produce display signals , only provide light source.

Inverter board is a DC to AC converter. It is low-voltage DC convert into high-

voltage AC, and supply to light up CCFL lamps.

CCFL Parameters

Parameter SymbolValues

UnitMin Type Max

Operating Voltage VBL 655 685 805 VRMS

Operating Current IBL 3.0 5.0 6.0 mARMS

Starting Voltage(at 0 C) Vs 1370 VRMS

Operating Frequency FBL 45 58 80 kHz

Power Consumption PBL 3.43 3.77 Watt

Inverter parameters(size:24)

Item symbol unitvalue

remarkMIN TYP. MAX

输入电压 input voltage Vin V 9 12 16

工作频率 operate frequency

foper kHz 40 50 80

调光电压 dimming voltage

Vdim V 0 5 Anode or cathode dimming

灯管电流 lamp current Ilamp mArms 3.0 7.5 8.0

工作电压Operating voltage

Vlamp Vrms 700 880 I lamp=7.5mA

启动电压Start-up voltage

Vopen Vrms 1250 Ta = 25 ºC

1650 Ta = 0 ºC

启动时间 start-up time Ts S 1 3

CCFL Operate Voltage Waveform

• CCFL lamp light, the voltage drop large, sine waveform change some distortion

CCFL operate voltage is 765V,normal CCFL operate voltage is 600V---800V,start voltage is as high as 1500V—1800V

Distortion sine waveform

765V

Block Inverter Diagram

Brightness adjustment

Input

CCFL and LED Dimming

Imaxinverter

fbVadj outout

Duty cycle regarding large dimming

fbVadj

inverter

out

Duty cycle regarding small dimming

Imax

LED dimming pricinple(PWM mode)

inverter

fbVadj out

Imax

inverter

fb Vadj out

Imax

Duty cycle regarding large dimming

Duty cycle regarding small dimming

CCFL dimming pricinple(Analog mode)

LED Chip Structure

LED Chip Structure

White LED structure

From phosphor layer From LED

Large area phosphor layer

High Brightness LED Structure

LED Advantages

•Low power consumption

• Extremely long lifetime

• Very low early failure rate

• Smallest

• Shockproof

• Does not produce UV radiation

Or intermediate frequency

interference

• Low power

• Light through the optical lens

transmitted out

• High color efficiency

•Low voltage

LED Bar of LED TV

•By a number of independent white LED light strip solder into the PCB (or aluminum plate) Installed in the frame on the screen (the side, both sides or multilateral)•Light of the length and the number of LED lamps according to the size of screen size varies•The LED light on the many uses of the series (some machines will be used in parallel or series-parallel hybrid) connected•A single light on one or more strings of LED•Require specialized multi-string LED constant current driver circuit to drive

LED TV Structure

LED vs CCFL• Brightness and the startup time

CCFL LED

LED vs CCFLLight remote control interference

CCFL Spectrum LED Spectrum

LED vs CCFL

CCFL ： need additional start-up high –voltage,stimulate mercury vapor.

LED ： The use of stable DC power supply, no additional start-up high-voltage

LED TV And LCD TV Differences

• LED TV and LCD TV's biggest difference is the different use of the backlight

• LCD TV uses CCFL (Cold Cathode Fluorescent Lamp) lamps, CCFL drawback is that lifetime

is short compared with LED and CCFL using raw materials containing mercury, mercury

pollution of the environment is a big injury

• LED TV: LED backlight that is used LED lamps. The disadvantage is higher the cost of LED

than CCFL , but lifetime is longer compared than the CCFL, and the mercury-free, less

environmental damage

CCFLLED

LED and CCFL Backlight Compare

• Environmental protection(Material does not contain mercury)

• Currently CCFL light efficiency of 60 to 100lm / w

• Currently LED light effect can be achieved about120lm / w

• Low power, Follow-up development can be achieved higher

• long lifetime(Up to 100,000 hours)

• support collor is very wide:excellent display color

• DC driver, Easy to dynamically adjust the brightness

• safety: CCFL high-voltage drivers, LED drivers only need low-voltage

• CCFL for the fragile glass products, LED chips for the semiconductor solid-state

LCD Panel Block Diagram

T-CON Board Introduction

Inverter Board Introduction

TFT-LCD Block Diagram

Power Converter(DC/DC Converter)

TimingController

VcomGamma

ReferenceVoltages

Source Drivers

Gat

e D

river

sTFT-LCD Panel

Data In(LVDS)

Backlightinverter Lamps

Power Infor

signal

Power Infor

Inverter

RSDS

Timing Controller

LVDSRx

ACC DCC

DataController

MemoryController

PLL

T-CON

RSDSRx

RSDSRx

SSCEEPROM

Memory(DDR)

LVDS Tx

FrontRSDSData

BackRSDSData

ACC : Accurate Color Capture DCC : Dynamic Capacitance Compensation

Control Signal&

Gate Signal

SSC : Spread Spectrum Clock

Input Signal DE Mode Only RGB 24bit Data Clock

LVDS Signal Input Data VESA JEIDA

RxIN0

RxOUT0 R0 R2RxOUT1 R1 R3RxOUT2 R2 R4RxOUT3 R3 R5RxOUT4 R4 R6RxOUT6 R5 R7RxOUT7 G0 G2

RxIN1

RxOUT8 G1 G3RxOUT9 G2 G4

RxOUT12 G3 G5RxOUT13 G4 G6RxOUT14 G5 G7RxOUT15 B0 B2RxOUT18 B1 B3

RxIN2

RxOUT19 B2 B4RxOUT20 B3 B5RxOUT21 B4 B6RxOUT22 B5 B7RxOUT24 HSYNC HSYNCRxOUT25 VSYNC VSYNCRxOUT26 DE DE

RxIN3

RxOUT27 R6 R0RxOUT5 R7 R1

RxOUT10 G6 G0RxOUT11 G7 G1RxOUT16 B6 B0RxOUT17 B7 B1RxOUT23

LVDS Signal Format

Resolution Aspect Ratio No. of Pixel Panel Size

HD15:9 1280 x 768 17”, 19”

16:9 1366 x 768 23”, 26”, 32”, 40”, 46”

FHD 16:9 1920 x 1080 40”, 46”, 5X”

Resolution of LCD TV

Signal Item Symbol Min Typ Max Unit

Clock

Frequency

Fclk 60 80 85 MHz

Hsync Fh 43 50 53 KHz

Vsync Fv 48 60 66 Hz

Horizontal timing

Display period

Thd - 1366

(1280)*- Clocks

Total Th 1368 1600 1800 Clocks

Vertical timing

Display period

Tvd - 768 - Lines

Total Tv 773 838 1200 Lines

Input Timing

Resolution : 1366 x 768

LVDS Format Option High : VESA, Low : JEIDA

No Signal No Signal

1 Vin(+5V) 11 GND

2 Vin(+5V) 12 Rclk-

3 Rx0- 13 Rclk+

4 Rx0+ 14 GND

5 GNN 15 Rx3-

6 Rx1- 16 Rx3+

7 Rx1+ 17 GND

8 GND 18 GND

9 Rx2- 19 LVDS Option

10 Rx2+ 20 N.C

Connector: DF14A-20P-1.25H(HIROSE) or Compatable

Model : 17”, 19”, 23” - HD

Input Pins Assignment

LVDS cable

No Signal No Signal

1 N.C(#1) 16 GND

2 N.C(#2) 17 Rx3-

3 N.C(#3) 18 Rx3+

4 GND 19 GND

5 Rx0- 20 N.C(#4)

6 Rx0+ 21 LVDS Option

7 GND 22 N.C(#5)

8 Rx1- 23 GND

9 Rx1+ 24 GND

10 GND 25 GND

11 Rx2- 26 Vdd(+5Vdc)

12 Rx2+ 27 Vdd(+5Vdc)

13 GND 28 Vdd(+5Vdc)

14 RxCLK- 29 Vdd(+5Vdc)

15 RxCLK+ 30 Vdd(+5Vdc)

Input Pins Assignment Connector: FI-E30S(JAE) or Compatible

Model : 23”, 26”, 32”, 40” - HD

LVDS Format Option High : VESA, Low : JEIDA

LVDS cable

Input Pin Assignment Connector: FI-E30S(JAE) or Compatable

Model : 40”, 46 - FHD

No Signal No Signal

1 Odd Rx0 - 16 Even Rx2 +

2 Odd Rx0 + 17 Even RxCLK -

3 Odd Rx1 - 18 Even RxCLK +

4 Odd Rx1 + 19 Even Rx3 -

5 Odd Rx2 - 20 Even Rx3 +

6 Odd Rx2 + 21 Ground

7 Odd RxCLK - 22 Ground

8 Odd RxCLK + 23 Ground

9 Odd Rx3 - 24 Ground

10 Odd Rx3 + 25 Ground

11 Even Rx0 - 26 5V Input

12 Even Rx0 + 27 5V Input

13 Even Rx1 - 28 5V Input

14 Even Rx1 + 29 5V Input

15 Even Rx2 - 30 5V Input

LVDS Cable

Connector : S14B-PH-SM3(JST) or Compatible

No Pin Name Pin Configuration

1 Vin Typ 24V

2 Vin Typ 24V

3 Vin Typ 24V

4 Vin Typ 24V

5 Vin Typ 24V

6 GND Ground

7 GND Ground

8 GND Ground

9 GND Ground

10 GND Ground

11 NC No Connection

12 B/L On/Off Inverter Enable

13 ADIM Analog Dimming 　

14 PDIM PWM Dimming

B/L On/Off 3.3V : On, 0V : Off

Analog Dimming 3.3V : Max, 0V : Min

PWM Dimming Duty 30% : Min, Duty 100% : Max

Input Pin Assignment(Inverter)

Inverter cable

19” 23” 26” 32” 40”

Lamp 6 U-Lamps 6 U-Lamps 8 U-Lamps 16 Lamps 20 Lamps

Input Voltage 24V 24V 24V 24V 24V

Output Current 4.5/~ /6.5 4.0/~ /7.0 4.5/5.5/6.5 4.0/5.5/7.0 4.0/5.5/7.0

PWM Dimming 30% 30% 30% 30% 30%

Analog Dimming O O O O O

PWM Frequency

170Hz 170Hz 170Hz 170Hz 170Hz

Lamp Frequency 60KHz 60KHz 60KHz 60KHz 60KHz

PowerConsumption

50W 70W 80W 110W 180W

Inverter Specifications

LED Backlight Driving Principle

Control Signal

It is panel ( part NO.:LC420WUE-SBA) power sequence

LCD Driving Circuit

It is panel ( part NO.:LC420WUE-SBA) power sequence

Power Sequence

TCL 26D20 LED drive circuit

26D20—MP3389 is step-up control for 12 strings LED driver

DC=24V to DC=12V converter

24Vconverter 38V DC-DC and Multi-channel constant current control output voltage

divider resistor

Adobe Acrobat Document

backlight ON/OFF control signal

PWM dimming signal

MP3389’s Circuit

Fromt mounting bracket

Panel serial NO.

After taking out open cell,we can see protection sheet

Take care braket

12

3

4

protection sheet

prim sheet(vertical)

prim sheet(horizontal)

Diffuser sheet

Cable

LED Panel Structure IntroductionFront LCD PANEL

Inverter board

T-con board

Open cell

Source board

Take care Tape Carrier Package

CCFL’S Socket

LED Panel Structure Introduction

LED lamp

Inverter board

Panel Serial NO.

T-CON board

LED poower supply socket

Front mounting bracket

Flexible printed cable

12

3

4

protection sheetprim sheet(vertical)

prim sheet(horizontal)

Diffuser sheet

LED panel

Open cell

After taking out open cell,we can see protection sheet

Backlight Structure Introduction

Power supply socket

Qty’s LED lamps:18 unit Qty’s LED lamps:18 unit

Two LED modules are parallel If Vinput=57V,Vone led=57/18=3.2v,so that one LED’s voltage is very low

For example:Part NO.: 4A-LCD32T-AUC panel,there are 36 LED lamp each LED unit

Two LED diodes,if one diode is defetive,the other diode can keep LED to light,two diodes is defetive,all LED cannot light

Solder on the PCB

LED Panel Module Introduction

The Others Introduction Front cabinet Panel

Power supply board

Main board

Stand base component

Rear cabinet

Front cabinet Panel

Power supply board

Main board

Rear cabinet

Open cellBacklight module

Common LCD TV structure

The other LCD TV structure

Gate TCP

Explain： 1 、 Gate PCB and Source PCB and FPC in the Board

（ FPC=Flexible Printed Cable ， PCB=Printed Circuit Board ）

2 、 TCP=Tape Carrier Package

Open Cell Structure

Source TCP

Source PCB+Gate PCB

Working Instruction of The Panel

CCFL bracket

Take care flexible printed cable

Reflector sheet

Assembly CCFL,take careCCFL not breaking

Take care :ccfl and socket connect

Assembly protection sheet\prim sheet(two\diffuser sheet

Assembly protection sheet\prim sheet(two\diffuser sheet

Finishing assemblying backliht module

Connect ground cable

Bring open cell to assembly

Put the open cell on the backlihgt module

Take care source gate board

Assembly bracket

Check here it is ok or not

Check panel it is ok or not

Tool’s moving opencell

LCD Trouble Shooting

Check power supply V=24V or 12V

CCFL is not light

Check power supply board

Check backlight on/off

Check main board Check backlihgt board

CCFL flash

Check backlight board

Check Vblihgt-dimming

or dimming

Check main board

N

N

N

Y

Y

Y

Y

（ 1）

（ 2）

N

Y

Check power supply V=24V

Check power supply board

N

N

Y

Check Vt-con?(power supplyof T-con board Vt-con)

Check Vt-con?(powersupply of T-con board Vt-con)

LCD Trouble Shooting

Check power supply V=24V or 12V

CCFL is light and then not light

Check power supply board

Check backlight on/offCheck main board

Check backlight board

check CCFL or connect to

CCFL cable or socket

checkCCFL or cable

N

NN

Y

Y

Y

ReplacePWM IC

N

NY

Y

CCFL is light to keep 2S,and then is

not light

Check CCFL socket Check CCFL’S socket or plug

Check transformer or feedback circuit

Check transformer’s voltage

Check OPV and OPC’s circuit

N

Check transformer’s feedback circuit

Check PWM’s OPV

and feedback circuit

Check MOS’S circuit

and feedback circuit

N

Y

Check transformer or capacitor

YY

Check OPC’s circuit

N

LCD Trouble Shooting

High Speed— megabits/second (Mbps) through gigabits/second (Gbps)

Low Power— x3.5mA current loop/output

Low Noise— low demands on power/ground— radiated electric fields tend to cancel

Low Cost— pure CMOS implementations

What is LVDS?

LVDS Timing

picture

HostSystemGraphic

Controller

T-conCMOS/TTL CMOS/TTL

Data(LVDS)

Clock(LVDS)

LVDS InterfaceData 4pair + Clock 1pair = 10 line

CMOS/TTL InterfaceData 24 line

Control 3 lineClock 1 line

CMOS/TTL InterfaceData 24 line

Control 3 lineClock 1 line

LCDModule

LVDS Tx LVDS Rx

▶ LVDS(Low Voltage Differential Signaling) - Interface between TV set and LCD module - 340mV swing - 7:1 Muxing - 100 ohm R-Termination - Reduce Data Bus Width

What is LVDS?

LVDS Signal Mapping

▶ RSDS( Reduced Swing Differential Signaling) - Interface between T-con and Source Drive IC - 200mV Swing - 2:1 Muxing - 100 ohm R-Termination - Reduce Data Bus Width

Driver

TFT - LCD

PANEL..

RowDriver

Timing Control

ColumnDriver

N

ColumnDriver

NColumnDriver

NSourceDriver

N

Driver

NSource

N

ONLY 24 Data Lines,RSDS (200mV) @ 80MHz

Row

. . . . . . . .

RGB Data(RSDS)Timing/Control

Clock(RSDS)

RSDSTx

TimingController

D0 D1 D0 D1 D0 D1 D0 D1 D0 D1

D2 D3 D2 D3 D2 D3 D2 D3 D2 D3

RSDS00

RSDS01

RSDSCLK

DIO

RSDS Signal Mapping

What is RSDS?

picture

TFT—Thin Film Transistor

LCD—Liquid Crystal Display

CCFL---Cold Cathode Fluorescent Lamp

LED-----Light Emitting DiodesHCFL -----Hot Cathode Fluorescent LampFMB ------Front mounting bracketFPC--------Flexible Printed Cable(It is the circuit that applies to printing circuit with LC driver IC and COG circuit interface.)TCP--------Tape Carrier Package BLU --------Back Light Unit CELL------- Cell( It is the panel of liquid crystal that fill into the micro meter gap formed by combining two glasses substrates.)Cell gap-----Cell Gap(It is the gap between ITO film on color filter substrate and TFT substrate.The size of the gap affects the transmittance of LCD display substrate and response time of liquid crystal.)CF-----------Color Filter (In order for LCD to generate colors,there is a pattern with Red,Green and Blue,which is one of the parts in the LC cell.Color filter is structured by 4 major components:Black Matrix to block light, pattern to display colors,transparent protection film made from protection pattern and transparent electrode film used for driver LC).CIE chromaticity diagram--------- CIE chromaticity diagram shows the graph of 2 dimensional color coordinate.On the XYZ color graph and X10Y10Z10 color graph,it uses x,y or x10y10 direct coordinate,and they are called CIE1931 color graph or CIE 1964 color graph.It is also known as xy or x10 y10 chromaticity diagram.

Appendix 

Appendix COF-------Chip On Film(It is a simplified termof chip on film,which is a method of connecting IC chip to the electrode terminal of flexible printed circuit board.The specialty of this IC package method can thinner the flexible printed circuit board,which is about one third of thickness of TCP.It also increases the reliability of the liquid crystal display module.The current connecting processes used are:conductivity film,conductivity paste and eutectic conjunction.)

COG-------Chip On Glass(It is a process of connecting electrode terminal of idisplay glass sub strate and I/O of Driving IC directly to each other.The Driving IC must have bumping,and the material used for liquid crystal substrate bumping is Au.The manufacturing process,which uses ACF as its connecting material,is more matred.)

COP--------Chip On Plastic(It is a simplified term of Chip On Plastic,which is a method of connecting IC chip to the electrode terminal of plastic substrate.It is used for setting the driver IC onto the liquid crystal panel of plastic substrate.

Contrast ratio-----The ratio between the maximum and minmum brightness when the LC is On/Off.The contrast changes with different viewing angles,and therefore,maximum contrast ratio is used for display.Generally,STN is 10:1 and TFT is 100:1 for display.

Data line------It is the perpendicular wiring used in TFT substrate to transfer display signals.Because it is connected with the Source electrode or Drain electrode on each pixel in TFT,it is also known as Source line or Drain line.The width of the line is often between few um to 10 um.

Appendix Driver IC-------It is the IC that drives the LCD.There two types of display matrix:Scanning electrode(column electrode)Driver and Signal electrode(row electrode)Driver.The package of driver changes from QFP to TCP.The Driver IC of poly-silicon LCD panel forms directly in the display screen.

Gray scale----- Gray scale is for tuning the display between maximum and minimum brightness.When digital signal is input to it,according to2,3,4,6 and 8 bit,there are 4,8,16,64 and 256 different gray levels.Analogue input can be used for infinity level tuning display.There are two ways of gray scale:LCD driving voltage tuning and frame rate control.

LCD Driver--------LCD Driver is for driving LC panel circuit or IC.In matrix terms,it can be differentiated into column electrode Driver and row electrode Driver.

Scanning line------It is the horizontal wiring line,which transfers signal to the gate electrode in TFT board,It is also known as gate line.It also has the function to select horizontal pixels.When the pixels are selected by the scanning line,the TFT is in a conductivity status,and signals can be written into each pixel from Data line.The signal delay in the scanning line causes great impact to the quality of the screen image,and therefore,low resisto scanning line should be used.