A pixel
M Common
A B
A pixel
B pixel
B pixel
Horizontal Cross talk of STN LCDs
A
SEG
L Line
A B
Common
Pixel Waveform
B L
CMO S
Epson SED1565 Block Diagram
Vss
VDD V1 V2 V3 V4
Segment Driver
Common Driver
STN LCD Driver Block
STN Common Driver
STN Segment Driver
EI/O
Shift Register
EO/I
EI/O
Shift Register
EO/I
Dcl
Dcl
k
k
D0~D8
Data Latch
LCD 靜態驅動 法
Vsig
Vc
ON Vsig Vc Vs Vc - Vs
Vs LC Cell
OFF
ON
II. STN LCD Driver introduction
Mobile Phone Market Forecast
Mobile Phone 600
Msets
500
400
300
200
100
0 2000 2001 2002 2003
STN Mono STN Color LTPS Color
STN PDA Market Forecast
PDA
12000
Ksets
10000
8000
6000
4000
2000
0 2000 2001 2002 2003
STN Mono STN Color
STN LCD Driver Introduction
Epson Voltage Reference Block
Vdd
Vout (from charge pump)
Vdd V1
V2 To Segment&
V3
Common
V4
V5
Epson OSC Block
V= VTn + VTp
Power for OSC
VI. TFT LCD Block Diagram
CAP1+ CAP1CAP2+ CAP2CAP3+ COUT
Power Supply Circuit
SEG0~SEG131
SEG Drivers
Display data latch circuit
Display data RAM 132x65
COM0~COM63
COM Drivers
Com Output Status select circuit
WFP2373 258 Gate Driver
1024x768 260K LCD panel
TFT LCD Market Forecast
45 40 35 30 25 20 15 10 5 0
2000
2001
I. 液晶 驅動 原 理 介紹
液晶 驅動 原 理
Field OFF
Field ON
Twist Nematic (TN)
Field OFF
Field ON
TN & STN V-T Transfer Curve
STN
T
DV2
TN
V
DV1
PS: TN more suitable for more gray levels STN for black & white
VEE Vss
Output Stage
To STN Common
LP V1~V4
Data Latch Output Stage
To STN segme
STN LCD Driving waveform
Column 1 Column 2
Common Signal
Line1 Line2 Line3 Column 1 Column 2
Line address circuit Display Timing generation circuit
Page address circuit I/O buffer
Column address circuit
OSC
Bus holder
Command decoder
Status
MPU interface
F
0
-F D -D
F+D D -D
-(F+D)
IAPT
F+D F
D Common
2D 0 Segement
F+D
LCD pixel
D -D
0 F+D
F-D
-(F+D)
Color on STN LCD - FRC
Frame rate control
=
4/4
=
3/4
=
2/4
=
1/4
=
0/4
Time
Color on STN LCD - PWM
SR
2
1:2
2.23
4
1:3
1.73
8
1:4
1.45
16
1:5
1.29
32
1:7
1.2
64
1:9
1.15
100
1:11
1.11
128
1:12
1.09
200
1:15
1.08
240
1:16
1.06
400
1:17
1.06
1.3
1.2
1.1
1.
0
100
200
STN LCD Driving Method
APT
Pulse Width Modulation
Segment Common
Pixel
Vertical Cross talk of STN LCDs
M Common
A B
A pixel
B A
B pixel
Reduce Vertical Crosstalk of STN LCDs
M Common
A B
液晶顯示器驅動IC原理和介紹
主講人 : 黃雲朋
Content
I. 液晶 驅動 原 理 介紹 II. STN LCD Driver Introduction III. STN Case Study VI. TFT LCD Driver Introduction V. TFT Driver IC Consideration
F+D
+D -D F-D +D -D F+D
+D -D
Segment Signal
Limitation on STN LCD Resolution
ON =
2
2
(F+D) + (N-1)D
N
OFF =
2
2
(F-D) + (N-1)D
N
ON SR =
OFF
F =N
D
SR =
N +1 N -1
N
Bias
Source Driver
Source Driver
from Notebook
LVDS
from Desktop PC
Or
LCD Controller (Panel Link
Or ADC)
LCD Control ASIC
Reference generator
WFP2373 Gate Driver
258