Training Manual of Panel (CCFL & LED)
CCFL Lamps Appearance U-shapes lamps
straight lamps
M-shapes lamps
Inverter Board Power supply voltage board and inverter board is one PCB
Inverter board
TFT-LCD Imaging Principle 1: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 filter enlarge
TFT-LCD Imaging Principle
TFT-LCD Imaging Principle
CCFL backlight 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.
4unit CCFL small size LCD TV
Lots of CCFL big size LCD TV
CCFL Parameters Parameter
Values
Symbol
Unit
Min
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
58
80
kHz
Power Consumption
PBL
3.43
3.77
Watt
45
Inverter parameters(size:24) Item
symbol
value
unit
MIN
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
灯管电流lamp current
Ilamp
mArms
3.0
工作电压 Operating voltage
Vlamp
Vrms
启动电压 Start-up voltage
Vopen
Vrms
启动时间start-up time
Ts
S
5
7.5
8.0
700
880
remark
Anode or cathode dimming
I lamp=7.5mA
1250
Ta = 25 ºC
1650
Ta = 0 ºC
1
3
CCFL Operate Voltage Waveform •
765V
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
Block Inverter Diagram
Input
Brightness adjustment
CCFL and LED Dimming CCFL dimming pricinple(Analog mode)
LED dimming pricinple(PWM mode) Vadj
Vadj
out
fb
inverter
fb
Imax Imax
inverter
Duty Duty
Vadj
cycle regarding large dimming
cycle regarding large dimming
fb
Vadj
out inverter
Duty
out
cycle regarding small dimming
fb
out inverter
Imax
Duty
cycle regarding small dimming
Imax
LED Chip Structure
LED Chip Structure
White LED structure
Large area phosphor layer From LED
From 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 seriesparallel 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
600.00 500.00 500.00 400.00
CCFL
400.00
LED
300.00
300.00
200.00
200.00
100.00
100.00 0.00 1 1723435146858561027 1198 1369 1540 1711 1882 2053
0.00 1 38 75112149186223260297334371408445482519556
LED vs CCFL Light 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 highvoltage
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
LED CCFL
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 In for Inverter
Data In (LVDS)
Backlight inverter
Timing Controller
Lamps
RSD S
Gamma Reference Voltages
Power In for signal
Power Converter (DC/DC Converter)
Gate Drivers
Source Drivers
TFT-LCD Panel
Vcom
Timing Controller SSC : Spread Spectrum Clock EEPROM Input Signal DE Mode Only RGB 24bit Data Clock
L V D S
SSC
Data Controller
LVDS Rx
ACC
T x PLL
ACC : Accurate Color Capture DCC : Dynamic Capacitance Compensation
DCC
RSDS Rx
Front RSDS Data
RSDS Rx
Back RSDS Data
T-CON
Memory Controller
Memory (DDR)
Control Signal & Gate Signal
LVDS Signal Format LVDS Signal
RxIN0
RxIN1
RxIN2
RxIN3
Input Data RxOUT0 RxOUT1 RxOUT2 RxOUT3 RxOUT4 RxOUT6 RxOUT7 RxOUT8 RxOUT9 RxOUT12 RxOUT13 RxOUT14 RxOUT15 RxOUT18 RxOUT19 RxOUT20 RxOUT21 RxOUT22 RxOUT24 RxOUT25 RxOUT26 RxOUT27 RxOUT5 RxOUT10 RxOUT11 RxOUT16 RxOUT17 RxOUT23
VESA R0 R1 R2 R3 R4 R5 G0 G1 G2 G3 G4 G5 B0 B1 B2 B3 B4 B5 HSYNC VSYNC DE R6 R7 G6 G7 B6 B7
JEIDA R2 R3 R4 R5 R6 R7 G2 G3 G4 G5 G6 G7 B2 B3 B4 B5 B6 B7 HSYNC VSYNC DE R0 R1 G0 G1 B0 B1
Resolution of LCD TV Resolution
Aspect Ratio
No. of Pixel
Panel Size
15:9
1280 x 768
17”, 19”
16:9
1366 x 768
23”, 26”, 32”, 40”, 46”
16:9
1920 x 1080
40”, 46”, 5X”
HD
FHD
Input Timing Resolution : 1366 x 768 Signal
Item
Symbol
Min
Typ
Max
Unit
Fclk
60
80
85
MHz
Fh
43
50
53
KHz
Fv
48
60
66
Hz
Display period
Thd
-
1366 (1280)*
-
Clocks
Total
Th
1368
1600
1800
Clocks
Display period
Tvd
-
768
-
Lines
Total
Tv
773
838
1200
Lines
Clock Hsync
Frequency
Vsync
Horizontal timing
Vertical timing
Input Pins Assignment Connector: DF14A-20P-1.25H(HIROSE) or Compatable Model : 17”, 19”, 23” - HD 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
LVDS cable
LVDS Format Option High : VESA, Low : JEIDA
Input Pins Assignment 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)
Connector: FI-E30S(JAE) or Compatible Model : 23”, 26”, 32”, 40” - HD
LVDS cable
LVDS Format Option High : VESA, Low : JEIDA
Input Pin Assignment 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
Connector: FI-E30S(JAE) or Compatable Model : 40”, 46 - FHD
LVDS Cable
Input Pin Assignment(Inverter) 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
Inverter cable
B/L On/Off 3.3V : On, 0V : Off Analog Dimming 3.3V : Max, 0V : Min PWM Dimming Duty 30% : Min, Duty 100% : Max
Inverter Specifications 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
Power Consumption
50W
70W
80W
110W
180W
LED Backlight Driving Principle Control Signal
LCD Driving Circuit
It is panel ( part NO.:LC420WUE-SBA) power sequence
Power Sequence
It is panel ( part NO.:LC420WUE-SBA) power sequence
TCL 26D20 LED drive circuit DC=24V to DC=12V converter
24Vconverter 38V DC-DC and Multi-channel constant current control output
voltage divider resistor
backlight ON/OFF control signal
PWM dimmi ng signal
26D20—MP3389 is step-up control for 12 strings LED driver
MP3389’s Circuit
LED Panel Structure Introduction Open cell
Front LCD PANEL
Take care braket Panel serial NO. Source board
1 Inverter board
T-con boar d
2
prim sheet(vertical) prim sheet(horizontal)
3 Take care Tape Carrier Package
protection sheet
4
Diffuser sheet
CCFL’S Socket Fromt mounting bracket
After taking out open cell,we can see protection sheet
Cable
LED Panel Structure Introduction LED panel
Front mounting bracket
After taking out open cell,we can see protection sheet
protection sheet
1
Panel Serial NO.
prim sheet(vertical)
2
prim sheet(horizontal)
3
Diffuser sheet
4
LED poower supply socket
Open cell Inverter board
T-CON board
LED lamp Flexible printed cable
Backlight Structure Introduction
LED Panel Module 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
The Others Introduction Front cabinet
Panel
Power supply board
Main board
Front cabinet
Panel
Power supply board
Main board
Open cell The other LCD TV structure Stand base component
Rear cabinet
Common LCD TV structure
Backlight module
Rear cabinet
Open Cell Structure
Source PCB+Gate PCB Source TCP
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
Working Instruction of The Panel Reflector sheet
Assembly protection sheet\prim sheet(two \diffuser sheet
Connect ground cable
Assembly bracket
Bring open cell to assembly
CCFL bracket
Assembly protection sheet\prim sheet (two\diffuser sheet
Check here it is ok or not Put the open cell on the backlihgt module
Assembly CCFL ,take careCCFL not breaking Take care source gate board Take care :ccfl and socket connect
Check panel it is ok or not
Finishing assemblying backliht module Take care flexible printed cable
Tool’s moving opencell
LCD Trouble Shooting （2）
CCFL is not light
Check power N supply board
Check power supply V=24V or 12V Y
N Check backlight on/off
Y N
Check Vt-con?(power supplyof T-con board Vt-con) Y
Check main board Check backlihgt board
CCFL flash
Check power supply V=24V
N
Check power supply board
Y Check Vblihgt-dimming or dimming
N
Y Check Vtcon?(powersupply of T-con board Vt-con)
N
（1）
Y Check backlight board
Check main board
LCD Trouble Shooting CCFL is light and then not light
Check power supply board
N
Check power supply V=24V or 12V
Y
Check main board
N
Y Check backlight on/off
check CCFL or connect to CCFL cable or socket Y Check backlight board
N checkCCFL or cable
LCD Trouble Shooting CCFL is light to keep 2S,and then is not light N Check transformer’s feedback circuit
N Check CCFL’S socket or plug
Check CCFL socket Check OPC’s circuit
Y
Check PWM’s OPV and feedback circuit
Y
N
Y Check transformer or feedback circuit
Check transformer’s voltage
N
N
Y Y Check OPV and OPC’s circuit
Replace PWM IC
Check transformer or capacitor
Check MOS’S circuit and feedback circuit
What is LVDS?
picture
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(Low Voltage Differential Signaling) - Interface between TV set and LCD module - 340mV swing - 7:1 Muxing - 100 ohm R-Termination - Reduce Data Bus Width
LCD Module
Data(LVDS)
Host System Graphic Controller
CMOS/TTL
CMOS/TTL
T-con Clock(LVDS)
LVDS Tx
LVDS Rx
CMOS/TTL Interface Data 24 line Control 3 line Clock 1 line
CMOS/TTL Interface LVDS Interface Data 4pair + Clock 1pair = 10 line
Data 24 line Control 3 line Clock 1 line
LVDS Signal Mapping
What is RSDS? ▶ 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
ONLY 24 Data Lines, RSDS (200mV) @ 80MHz
RGB Data(RSDS) Timing Controller
RSDS Tx
Timing/ Control
N Source Column Driver
........
Clock(RSDS)
RSDS Signal Mapping
Timing Control
Row Driver
. .
RSDSCLK
NN Source Column Driver Driver
- LCD TFT PANEL
Row Driver
DIO RSDS00
D0 D1
D0 D1
D0 D1
D0 D1
D0 D1
RSDS01
D2 D3
D2 D3
D2 D3
D2 D3
D2 D3
picture
Appendix TFT—Thin Film Transistor LCD—Liquid Crystal Display CCFL---Cold Cathode Fluorescent Lamp
LED-----Light Emitting Diodes HCFL -----Hot Cathode Fluorescent Lamp FMB ------Front mounting bracket FPC--------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 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.
