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CONFIDENTIAL
TFT-LCD TV/MONITOR
Chassis Model
NK15N* LTM1575W
NK17N* LTM1775W
Training Manual
TFT-LCD TV/MONITOR CONTENTS
1. Introduction of TFT-LCD
2. Specifications
3. Alignment & Adjustments
4. Block Diagram
5. Troubleshooting
6. IC Specifications
7. Samsung LCD TV's sales points
8. General Informations of LCD
9. Schematic Diagrams
Visual Media Division Global CS Team
Quality Assurance Group
Samsung Electronics Co.,Ltd.
416, Maetan-3Dong, Paldal-Gu, Suwon City, Kyungki-Do, Korea.
Printed in Korea
Published by S.K.Yang / Manager of VD Division
May 2002
CONFIDENTIAL
2. Product Specifications
1 Specifications
Description
Item
LTM1575W LTM1775W
LCD Panel TFT-LCD panel, RGB vertical stripe, normaly TFT-LCD panel, RGB vertical stripe, normaly
white, 15-Inch viewable, 0.2895 mm pixel pitch white, 17-Inch viewable, 0.2895 mm pixel pitch
Scanning Frequency Horizontal : 30 kHz ~ 61 kHz (Automatic)
Vertical : 56 Hz ~ 75 Hz (Automatic)
Display Colors 16.2 Million colors
Maximum Resolution Horizontal : 1280 Pixels
Vertical : 768 Pixels
Input Video Signal Analog 0.7 Vp-p ± 5% positive at 75 , internally terminated
Input Sync Signal Type : Seperate H/V
Level : TTL level
Maximum Pixel Clock rate 80 MHz 80 MHz
Active Display
368.0 mm / 236.0 mm 370.560 mm / 222.336 mm
Horizontal/Vertical
AC power voltage & Frequency AC 90 ~ 264 Volts, 60 / 50 Hz ± 3 Hz
Power Consumption 50 W (Max) 53 W (Max)
Dimensions
Unit (W x D x H) 19.6 x 8.0 x 14.7 Inches (498 x 204.5 x 374 mm) 21.1 x 8.0 x 15.8 Inches (536 x 204.5 x 402 mm)
Carton (W x D x H) 22.5 x 17.4 x 10.6 Inches (571 x 441 x 269 mm) 24.0 x 18.3 x 10.6 Inches (609 x 465 x 269 mm)
Weight 3.95 Kg (8.7 Ibs) 4.8 Kg (10.6 Ibs)
Environmental Considerations Operating Temperature : 50 °F ~ 104 °F (10 °C ~ 40 °C)
Humidity : 10 % ~ 80 %
Storage Temperature : -4 °F ~ 113 °F (-20 °C ~ 45 °C)
Humidity : 5 % ~ 95 %
Tunning Frequency Synthesize
TV System System NTSC-M
Sound STEREO
Antena Input 75, Coaxial Cable
MAX Internal speaker Out : Right => 3W Right => 5W
Left => 3W Left => 5W
Sound Characteristic
BASS Control Range : -12 dB~ + 12 dB
TREBLE Control Range : -12 dB~ + 12 dB
Headphone Out: 5mW max (400m Vrms)
Output Frequency : RF => 80 Hz ~ 15 kHz
A/V => 80 Hz ~ 15 kHz
LTM1575W/LTM1775W
Product Specifications
CONFIDENTIAL
2 Pin Assignments
2-1 D-SUB 2-2 DVD, DTV
Pin Separate Y
RCA Green
1 Red GND
2 Green
3 Blue Pb (Cb)
4 GND RCA Blue
GND
5 GND (DDC Return)
6 GND-Red Pr (Cr)
7 GND-Green RCA Red
8 GND-Blue GND
9 No Connection
Audio L
10 GND-Sync./Self Test
RCA White
11 GND GND
12 DDC Data
13 H-Sync. Audio R
14 V-Sync. RCA Red
15 DDC Clock GND
2-3 S-Video 2-4 A/V
Pin Separate RCA Yellow CVBS
1 GND Audio L
2 Y RCA White
3 C GND
4 GND
Audio R
5 GND RCA Red
GND
LTM1575W/LTM1775W
Product Specifications
CONFIDENTIAL
3 Timing Chart
This section of the service manual describes the timing that the computer industry recognizes as standard
for computer-generated video signals.
3-1 LCD Panel Mode : 1 mode
µs
µs
µs
µs
µs
µs
µs
µs
LTM1575W/LTM1775W
Product Specifications
CONFIDENTIAL
3-2 Supported Modes (1)
µs µs µs µs µs
µs µs µs µs µs
µs µs µs µs µs
µs µs µs µs µs
µs µs µs µs µs
µs µs µs µs µs
µs µs µs µs µs
µs µs µs µs µs
LTM1575W/LTM1775W
Product Specifications
CONFIDENTIAL
3-2 Supported Modes (2)
µs µs µs µs µs
µs µs µs µs µs
µs µs µs µs µs
µs µs µs µs µs
µs µs µs µs µs
µs µs µs µs µs
µs µs µs µs µs
µs µs µs µs µs
LTM1575W/LTM1775W
Product Specifications
CONFIDENTIAL
3-2 Supported Modes (3)
µs µs
µs µs
µs µs
µs µs
µs µs
µs µs
µs µs
µs µs
2-6 LTM1575W/LTM1775W
Alignments and Adjustments
3. Factory Mode Adjustments
1 Entering Factory Mode
1. To enter "Service Mode" Press the remote -control keys in this sequence :
- If you do not have Factory remote - control
- If you have Factory remote - control
2 Factory Mode Tree
LTM1575W/LTM1775W
Alignments and Adjustments
LTM1575W/LTM1775W
The Block diagram of TFT-LCD Monitor Main Board
FRC
SDRAM IAMGE To Panel
Scaler L
CONTROL Ctr. Board
V
OSD D
S
To Panel
Inverter
To Func.Brd. Micom
ADC from
CVB S
EEP S-video
To LED & IR. ROM H-PHON E
Power
From From From From
From Power Adapter DVD DTV PC R/F Data Path
Analog To Digital Converting
255 T1 : 0
254 T2 : 2
253 ¡á ADC(Analog to Digital Converter)
. . It is a device to conver analog
t
ADC
. . signal to dig ital signal and applied
. T5 : 255 80MHz-120 H M z
2 .
1
.
0
T1 T2 T3 T4 T5 T6 T7 T8 T7 : 2
¡á FRC(Frame Rate Conversion):
¡á FRC(Frame Rate Controller)
:
It is a convertin part/m
g ethod that constantly
converts the various vertical frequenc (50-95Hz)
ies
of variousmodes inputtedin diversity.
75
60
FRC
56
60
Scaling concept: It converts the resolution signal inputted in various forms to WXGA 1280x768
¡á Image Scaler :
We hav an his ic
e tor We have an historic
missio of national
n Scaling A technique to change the inputted
mission of national
res rati
to on resolution to the other resolution.
restoration
( EX. 640x480 1024x768 )
¡æ
miss ion mi ssion
¡áFine adjustment
c:\program
files...\pc2.wmf
¡á FINE:
Adjustmen of the monitor's
t
distinction by adjusting the
positional difference between
video signal and video clock.
Adjustment of Coarse
c:\program
files...\pc2.wmf
¡á COARSE :
n jus ing
(Fi e ad tmentof a videoclockfor match videoclocksoccurred between
inputted eo bandand PLL
vid )
Block Diagrams
NIKE LCD-TV NTSC adjustment RESISTOR
-When video gain is 100%, it is 70 %IRE.
(TOCHIBA PATTERN)
2)MN82860 GAMMA : OFF
(1) iw dc 71 07 iw dc 71 00
GAMMA DATA(GAMMA OFF)
MN82860 SUB ADRESS GAMMA ON
Order MN82860 SLAVE ADRESS
3) Highlight adjustment (x:282 y:283 T:10,000K )
(1) Patte rn adjus tment : FULL WHITE PATTERN (VIDEO GAIN 140£¥)
-.Af ter it is inputted at chassis to panel with RGB Full Gain, it c an be
adjusted to the coordinates where you wish by us ing CA110.
(2)Adjustment address an d adjustment
iw dc 3e ?? -->RED GAIN
(X value adjustment)
iw dc 3f ?? -->GREEN(Y value adjustment)
GAIN
iw dc 40 FF-->BLUE GAINvalue adjustme nt) -->FIX
(Y
-. The ratio of input/o utput is outputted 1:1 at MN82860 when RGB gain
value is FF.
-.Among charac ters of the RGB reproduc tion, a character of blue reproduc tion
is the lowest. If you wan t to have white c oordinates , you must outp ut the
blue higher at chass is.
(3) The reason why gamma has to be off at 2)
-The RGB Gain has to be adjusted in the s tate of gamma-Off becaus e
the MN82860 gamma co rrection is located at the end of colum n
afte r adjustment of RGB cut-off and g ain.
-.Af ter the gamma correction is set finally, the RGB Gain has to be
adjusted in the s tate of gamma-On for productio n.
* As mentio ned above, check the gain voltag e when you change
the p attern, then adjust. *
- It h as t o be c onfir me d bec a use the c ut- off is a little bit twist ed wh en adj usti ng t he gra y sc al e.
If it is not m atc h ed to th e a dju stme nt spec , repe at th e st ep (2 ) of 2. After adju stm ent, ret ur n to
th e gr ay sc a le and per for m th e fine adj ustm ent fo r ea ch step.
(The va lue s ar e alr ea dy a dju sted , so t he re will not be bi g di ffer enc es. )
-Adju st th e Toshiba patt er n a nd gr ay sc a le patter n repe at edly.
-After finish ed th e a djust me nt , ch ec k it in th e Fu ll-wh ite pa tte rn.
(Do not for get to m ea sur e th e ga in volta ge. )
If whi te is twiste d, repe at th e a bove. (Ga mm a off in full wh ite )
3.FACTORY MODE½Ã MICOM SETTING
-MODE:
DYNAMIC MODE / COOL
BLUE FIX
CONTRAST:80 ,BRIGHTNESS:50
5. Troubleshooting
1 No Power
Does proper DC 14V appear at DC No WAVEFORMS
Check SMPS PCB and Adapter.
jack connected to CN801?
1 IC811 #2
Yes
Does proper DC 3.3V_A No
Check IC811.
appear at FT852?
Yes
Does proper DC 2.5V_A No
Check IC802.
appear at Pin 3 of IC802?
2 IC805 #1
Yes
Does proper DC 3.3V_B No
Check IC805.
appear at FT822?
Yes
Does proper DC 2.5V_B No
Check IC806.
appear at Pin 4 of IC806?
3 IC812 #2
Yes
Check IC812.
LTM1575W/LTM1775W
Troubleshooting
CONFIDENTIAL
2 No Video (PC Signal)
Power indicator is green.
Yes
Does the signal appear No
at C491, C489, C488 Check CN401 and cable.
of R, G, B input?
Yes
Does the clock pulse appear at No
Check related circuit of IC350.
output of RA351 ~ RA356?
Yes
Does the clock pulse No Check R354 and related WAVEFORMS
appear at R354? circuit of R354.
4 X201
Yes
Does the clock pulse No Check X201 and related
appear at X201? circuit of X201.
Yes
Does the clock pulse appear at No
Replace RA301 ~ RA306, IC300.
output of RA301~RA306?
Yes
Replace LCD Panel.
LTM1575W/LTM1775W
Troubleshooting
CONFIDENTIAL
3 No Picture (TV, Video, S-Video, DVD, DTV)
Check Pin 185, 196 (S-Video) No Check the CN888 (Tuner) and the
and Pin 184 (VCR) and Pin 183
CN702-1 (VCR connector).
(RF-CVBS) of IC200 (DPTV_3D).
Yes
Does the signal appear at No Check the IC200
IC200 and +3.3V_BA? and related circuit of IC200.
Yes
Check the IC200, C285, C241 and C249.
LTM1575W/LTM1775W
Troubleshooting
CONFIDENTIAL
4 No Sound
Does the signal appear at
Pin 67 (Tuner sound signal) and Pin Check the CN403 (PC conector) and the
No
47, 48 (PC sound) and Pin 56, 57 (VCR CN402 (VCR connector) and the CN200
sound) and Pin 53, 54 (DVD) Pin 50, (DVD) and the CN888 (Tuner).
51 (DTV) of IC 919 (MSP3421)?
Yes
Does the signal appear at Pin 27, No Check the IC919 and
28 of IC919 (MSP3421)? related circuit of IC919.
Yes
Does the signal appear No Check the IC501 (Audio amp) and
at L501 ~L504? related circuit of IC501.
Yes
Replace the speaker.
LTM1575W/LTM1775W
Extra
TROUBLESHOOTING
If the TV seems to have a problem, first try this list of possible problems and solutions.
If none of these troubleshooting tips apply, call your nearest service center.
Identifying Problems
Problem Possible Solution
Poor picture Try another channel.
Adjust the antenna.
Check all wire connections.
Poor sound quality. Try another channel.
Adjust the antenna.
No picture or sound. Try another channel.
Press the TV/VIDEO button.
Make sure the TV is plugged in.
Check the antenna connections.
No color, wrong colors or Make sure the program is broadcast in color.
tints. Adjust the picture settings.
If the set is moved or turned in a different direction, the
power should be OFF for at least 30 minutes.
Adjust the antenna.
Picture rolls vertically. Check all wire connections.
The TV operates erratically. Unplug the TV for 30 seconds, then try operating it
again.
The TV won't turn on. Make sure the wall outlet is working.
Blurred or snowy picture, Check the direction, location and connections of your
distorted sound aerial.
This interference is often due to the use of an indoor
aerial.
Remote control malfunctions Replace the remote control batteries.
Clean the upper edge of the remote control
(transmission window).
Check the battery terminals.
"Check Signal Cable" Ensure that the signal cable is firmly connected to the
message. PC or video sources.
Ensure that the PC or video sources are turned on.
TROUBLESHOOTING
TROUBLESHOOTING
Problem Possible Solution
"Not Supported Mode!" mes- Check the maximum resolution and the frequency of
sage. the video Adapter.
Compare these values with the data in the Display
Modes Timing Chart.
The image is too light or too Adjust the Brightness and Contrast.
dark. Adjust the Fine function.
Horizontal bars appear to Adjust the Coarse function and then adjust the Fine
flicker, jitter or shimmer on function.
the image.
Vertical bars appear to flicker, The TV is using its power management system.
jitter or shimmer on the Move the computer's mouse or press a key on the
image. keyboard.
Screen is black and power Check that the display resolution and frequency from
indicator light blinks steadily. your PC or video board is an available mode for your
TV. On your computer check: Control Panel, Display,
Settings.
Image is not stable and may If the setting is not correct, use your computer utility
appear to vibrate. program to change the display settings.
NOTE: Your TV supports multiscan display functions
within the following frequency domain:
· Horizontal frequency: 30 kHz ~ 61 kHz
· Vertical frequency: 56 Hz ~ 75 Hz
· Maximum refresh rate: 1280 x 768 @ 60 Hz
Image is not centered on the Adjust the horizontal and vertical position.
screen.
You need the Monitor driver Download the driver from WWW pages:
software. http://www.samsungusa.com/monitor
TROUBLESHOOTING
"Nature ".
After the G. H Heilmeier group of the Sharp presented the first
possibility of LCD' s practical use in 1968, the first segment type of
the DSM style LCD electronic calculator, `EL - 805 ', was
commercialized in 1973. But, it has several problems such as black -
and -white display, responding speed, narrow viewing angle, high
power consumption for portability, and so on.
¢Ñ Responding speed: It is taking time that LCD element becomes On
or Off. When voltage signal from external
changes it On to Off or Off to On, a LCD is
changed due to the signal. But, it cannot be
changed immediately because of the viscosity of
the liqui d crystal, so time delay for reaching the
liquid crystal to equilibrium state is occurred .
Such transformational characteristic shows up
as an optical characteristic, and the delay time
for the optic is called responding time. The
responding time is prop ortional to the viscosity
of the liquid crystal and inversely proportional
to the cell spacing. When the electronic signal
is converted to On/Off, the responding time can
be measured from the transmission
characteristic in contrast with the time.
"WD-250 " with
STN LCD in 1986. It was the beginning to rapidly distribute the LCD
and to develop the word processor and PC.
Nevertheless, the STN LCD us es two display colors, yellow and blue,
to get enough luminosity for high contrast. The LCD needs clean
white - and - black display color to be regularly substituted for CRT
instead of OA. With the reason, DSTN (Double STN) style LCD,
displays beautiful blac k - and -white, is developed in 1987, and it is
commercialized .
* STN Color Word processor and DSTN color LCD notebook *
The materialization of the black and white display is opened the way
of the gray scale and color display period, and it helps to access to
PC following word processor. Afterward, LCD is developed for
better conditions such as lighter weight, thinner thickness, higher
resolution for larger screen, higher contrast, and wider viewing angle.
¢Ñ The gray scale: It is a display method that th e different state
exists except On/Off state. The huge
amount of information such as color display
cannot be displayed with only On /Off drive.
In the gray scale display, several middle
states exist between an On and Off state.
For example, there is gray state between
black and white to display information. The
gray scale is made by applying middle power
between On and Off power in LCD. There
are several methods to get a middle value:
control the strength of the power, adjust the
rage of the power pulse , and so on. The
color display is determined by the degree of
" color TV with the TFT_LCD is developed in 1986, LCD has
been larger, and t echnique suitable for the larger size has been
developed . At the present, 40" LCD is developed.
Through the continuous efforts for developing LCD for 4 and half
centuries , the flat display is made at present.
The strong parts of TFT_LCD compared to CRT are lighter weight,
thinner style, and lower powe r consumption. In the efficiency aspect,
the viewing angle, luminance, and contrast are near or even better
than CRT. But, price and responding speed is still not so good as the
CRT. In case of the viewing angle, if it is 15 ", left and right is 110 ¡Æ
~160 ¡Ætop and bottom is 90¡Æ ~160 ¡Æwhich is no problem to watch.
,
The luminance is maximum 200~250cd, and the contrast ratio is
200:1~300:1 which is better than CRT. The responding speed for
TFT_LCD is several tens ms (15" : 30ms~50ms) and for the STN_LCD
is se veral hundreds ms. For display a moving picture, the frequency
of the frame is 60Hz, so it must be 16ms. But, the frequency of
? Liquid Crystal
Liquid crystal seems like a liquid at a glance, but it is in a unique
state showing anisotropy like a crystal. It is an organic compound
called "Thermotropic liquid crystal" becomes a liquid crystal in
certain temperature range.
There are reflection type and backlit type of LCD. The reflective
LCD reflects the incoming light from the front side of the LCD panel
to the reflection board mounted to the backside of the panel. The
backlit LCD expresses an image by taking surrounding l ight or
fluorescence from rear side.
? Driving principle
The liquid crystal is contacted to the aligned surface for inducting the
direction of the liquid crystal, and the liquid crystal molecules are
arranged in parallel with the alignment film hollow. All liquid crystal
`twisted molecule arrangement' ). Therefore , the liquid crystal
molecules are twisted 90 degree between both substrates in
succession, and the light advances in the same direction with the
molecules. As shown in the figure, if the molecules are twisted 90
degrees, the light takes same direction with the molecules in twisted
90 degrees.
¢Ñ Liquid crystal: There is a mesophase exists in the natural world
with three common states, solid, liquid, and gas.
The mesophase is called liquid crystal phase. It
has characteristics, fluidity of liquid and positional
system of crystal, in the certain temperature range.
The liquid crystal phase is divided into Nematic,
Smectic, and columnar phase. The phase of ¿Âµµ
ÀüÀÌÇü ¾×Á¤ is changed by temperature, and phase
of ³óµµ ÀüÀÌÇü ¾×Á¤ is changed by density.
±×¸² »ðÀÔ [Liquid crystal molecules are arranged in parallel t o the
aligned film hollow.]
±×¸² »ðÀÔ [Liquid crystal molecules are twisted 90 degree between
both substrates.]
By adding voltage or external force with TFT, the direction of the
liquid crystal is coming undone from the state of twisted in 90 degree.
The dir ection is arranged in one direction to the panel surface
vertically, and the light goes straight.
Consequently, the matter of passing the incoming light is depending
on the conditions (twisted or untwisted) of liquid crystal. By adding
the polarizing to the both glass boards, the light passed through the
liquid crystal is collected in one direction again, and it is entered into
the picture element to be appeared on the screen finally.
? Principle of expressing colors
In the beginning, LCD supports only black color. Nevertheless, as
the application range of LCD is getting wider, and the display market
is getting changed toward to the color, the LCD has developed to
support colors.
LCD uses the color filter, which has three primary colors of red,
? Resolution
The r esolution is another primary characteristic of display. The
resolution is a measurement to express an image in detail. As
resolution is higher, the quantities of picture elements are getting
more. It means that the amount of data treated by drive IC during
unit of time is larger; therefore, the processing speed reaches near to
's operation
such as instrument or communication facility of airplane,
pulse generator of hospital, etc. Recently, Korea
government also proces ses to establish the restriction low
due to the studies.
? Construction of color TFT _LCD module
Color TFT_LCD is divided into a - Si ( amorphous silicon) TFT and p -
Si (polysilicon) TFT. The direct view TFT_LCD using a - Si TFT is
the most widely used.
TFT _LCD is roughly divided into the following 3 units.
First, panel with liquid crystal implanted between substrates.
Second, driving circuit includes Driver LSI for driving panel and PCB
(printed circuit board) with circuit element.
Third, chassis structure with backlight.
" and 18 " LC desktop
monitors are the most popular in the world. For increasing the
market share in the display field, the technique for larger size screen
has to be developed.
In the technical a spect, it is difficult to maintain the LC space equally
because the LC weight gets together into the middle if it is larger size.
The picture quality becomes low due to the distribution of the unequal
space.
Due to the weakness, PDP is developed for the 20 ", but its market
share is small because of its expensiveness. Therefore, it is
expected the lots of technical developments of the LCD for the flat
display device with its high market share.
3. CRT monitor and LCD monitor
¡ß The weakness of the LCD compare to the CRT
¢Ñ Viewing angle, after image, quantity of display color,
responding speed
¡ß The strong point of the LCD
¢Ñ Consumption power, electromagnetic wave, size (saving space),
picture quality (focus, GD, CG)
¡ß Equivalence (no problem to use and possible compensation):
¢Ñ Maximum luminance, contrast, flicker
' s weakness. It is no problem to
watch the 120¡Æ of right and left and 110 ¡Æ top
of
and bottom . But, if many people watch one screen,
the color is turning over due to the changing
viewing point with moving a head little bit to the
top, bottom, right, or left. Especially, as size is
larger, the viewing angle must be bigger; therefore,
the technical development is necessary for larger
screen.
¢Ñ Responding speed: The responding speed is slow because of the
LD's characteristic of the molecules.
Generally, it is no problem doing word process
and moving picture not to fast, but for the
game and real movie, the picture quality is
getting worth due to short on/off time of the
LC.
¢Ñ After image: When trying to express another image after certain
image is stoppage in long time, the first image
pattern reminds on it called after image.
¢Ñ Number of colors: If the sub - pixels (red, green, blue = 6 bits e ach)
adopt the panel consists of 18 bits, various
colors can be expressed by controlling the
luminance of the sub -pixel in several level
even though the number of sub - pixel is 18.
The possible expressing numbers of colors are
16,700,000 (2 to 6 th power = 256 levels).
It is the same case as the sub- pixel is 24 bit
(2 to 24 th power). CRT has analog signal. It
means that CRT supports all colors with
graphic card. In comparison with the CRT,
the possible expressing color numbers of the
LCD is still deficie ncy.
' s consumption power is 33% of the
CRT 's. For example, If PC is used 8 hours
per a day for year, the consumption power of
the CRT monitor will be 306,600w
(105x8x365=306,600w), and the consumption
power of the LCD monitor will be 102,200w
(35x8x365=102,200w).
If the average electric charge is 75won per
1kw/h, the consumption power for year will
be 22,995won (306,600x75=22,995) for CRT
and 7,665won (102,200x75=7,665) for LCD.
The differenc e, 15,330 won, is small amount
for person, but nation. The low consumption
power is good aspect for the TFT - LCD
monitor mounted to the note PC due to
portability and battery waiting time (time to
use for one charge), but for the TFT_LCD
mounted to Desktop monitor. But the
advantage of the LCD monitor cannot be
ignored due to the environmental protection
tendency of the current time.
¢Ñ Electromagnetic frequency: In comparison with the LCD, the CRT
monitor (certified TC099) makes high
frequency, which affects to human body.
Therefore, the LCD monitor is used in
hospital, laboratory, and so on because
precision machine could be malfunctioned by
electromagnetic frequency.
¢Ñ Weight: The CRT is 20kg and the LCD is 5.5kg, which means
the weight of th e LCD monitor is 28%(1/4) of the CRT
monitor. It is a great advantage for the note PC
monitor and desktop monitor. But the flat CRT monitor
" is
actually 16 ". Nevertheless, the actual size
of the TFT LCD is same as spec. The
visible picture size of CRT 17 " is 310x230,
and LCD 15.1" is 307x230. There is just
3mm difference horizontally. In other word,
17 " CRT mo nitor and 15.1" LCD monitor is
almost same size.
¢Ñ Picture quality: The problems, luminance, contrast, etc, in the
developing process of the LCD, are almost
solved. About the picture quality, the pixel
concept of the CRT is unclear, and the CRT
adopts the polarizing device to scan a beam
physically. As a result, there can be
differences of focus, cg, gd, etc. between
every products and even fine products.
Nevertheless, because the pixel position of
the LCD is fixed, there are no differences of
the focus, cg, gd, etc. between products. If
- In comparison with CRT monitor, it supports the fine enviro nment
for taking small space (less than 1/3 of CRT).
- User can get nice interior effect.
- In comparison with CRT monitor, it expresses an image vividly.
- It is comfortable to use visually for long time use.
¢º No screen flickering
- There is no flickering screen because individual active elements
exist in each picture element.
- There is no tiredness of eyes for long- term work.
¢º Almost no electron wave is occurred .
- In comparison with the CRT monit or, almost no electron wave,
which may harm human body, is occurred .
- It doesn 't affect to other device with electron wave. (It is suitable
for hospital, military, laboratory, etc.)
- In the future, TFT_LCD monitor will be dealing with all application
devices instead of CRT.
¢º Low consumption power
- It is low -consumption - power monitor, 32w, so it is suitable
monitor for bank, office, stock market, telemarketing, control
devices, etc.
- It minimizes the calorific value to supply fine work environment.
* DCT monitor is basically driven by RGB signal, and it has
construction that the electron from the electron layer is polarized by
crushing to the glass of fluorescent materials for creating light.
TFT_LCD monitor drives the liquid crystal panel to display an image.
The TFT_LCD has construction different to the CDT. Liquid crystal
is filled in between two glasses, and electrode is connected into each
liquid crystal cell. By applying voltage, the construction of the liquid
crystal 's molecule is changed for controlling light comin g from
backlight. The TFT_LCD has several advantages in comparison with
- Generally, it has
nice interface with
graphic board.
- It doesn' t need to
't need ADC and DAC. buy a new graphic
Low price. board.
- There is no defined - There is signal loss
standardization . (P&D, DFP, and during signal
DVI) conversion, digital to
- Interface problem analog, and analog to
Disadva
- The graphic board with digital digital.
ntage
interface is needed additionally . - Cable gets effect
Also, it is difficult to find it. from external.
- ADC or DAC is
needed. High price.
[Comparison between digital monitor and analog monitor]
¢º Digital era
All the information is getting digitalized. For example, the
information from the Internet is digital. Also, TV programs from the
North America , Europe , and Japan are broadcasted in digital. In the
near future, all TV programs will be bro adcasted in digital, and it has
been prepared. In Korea, some digital programs are already
introduced, and DVD movies are increased in number. With the
' s market share will be expanded in the
future.
¢º Why aren 't there many digital monitors?
The reasons that the digital monitor cannot be popular are: first, as
mentioned above, the analog market is too big, and the manufacturing
companies don' t invest for it. Second, there is no standardization for
wider use. The VGA interface for digital method is not standardized,
so the monitor manufacturing companies or graphic board
manufacturing companies are unwilling to produced it.
¢º What kind of VGA interfaces exist?
Mainly, P&D, DTP, DVI, etc. are adopted recently.
P&D (digital plug & play) was adopted by VESA in 1997, and it is
transfer protocol with TMDS method, called panel link. The digital
connector with P&D method transfers both of analog and digital. But,
price is raised by attaching t he solution (combination of USB and
IEEE 1394/Flrewire signal ) to achieve the transmission. Any of
graphic board manufacturing companies doesn' t have interested in
such expensive connector, so it couldn 't be standardized. The
Compaq makes DFP (digital fl at panel), which has similar function
with P&D, but price is lower. The functions are almost same as P&D
except analog signal, USB, and IEEE 1394 which are dropped off due
to high price. The transfer protocol is same as P&D and TMDS
method. The weak poi nt of the DPF is that the maximum resolution
is limited at SXGA (1280x1024), and it can 't take the graphic board
and analog monitor because it transmits only digital. It is expected
that the DFP connector can 't be stand longer with the weaknesses.
¢º What is the DVI?
' s digital monitor.
¢º The advantage when the DVI is adopted
The main problem of the analog VGA standard is quality difference of
output signal among the manufacturing companies and graphic board
companies. But if DVI standard is standardized, the quality
difference among companies will be reduced. As the results, the
technical gaps of products, CDT monitor, will be raised clearly among
companies. Also, the DAC is attached to CDT, which is the fact to
raise price. In the quality aspect, there is no unnecessary process in
comparison with analog method, so the picture quality will be
improved.
The price of the digital monitor will be down because it doesn 't need
to attach the ADC (analog to digital converter), and its picture quality
's see digital monitors introduced in Comdex show on Nov., 1999.
All prices are standardization on Nov., 1999. The digital CRT
monitor produced by Samsung is 21 Syncmaster 990 DVI. The 21
Syncmaster 990 DVI is CRT monitor, and it supports high resolution
(UXGA level (1600x1280)) and either of digital signal and analog
signal. Price is about 1,450,000 won. The ViewSonic introduces
OptiSync PF77, 17" flat CRT monitor, and OptiSync PF97, 19" flat
CRT monitor. T hey support either of analog signal and digital signal.
Price of PF97 is $625, and PF77 is $429.
Let 's see digital TFT LCD monitor.
Hewlett Packard introduces 15" Pavilion FX70. It supports DFP,
P&D, DVI, and analog. Price is $1,099. The ViewSonic has VP181,
18" digital TFT LCD, and VP151, 15" digital TFT LCD.
They have video input, two digital inputs, and two analog inputs.
Price of the VP181 is $3,795, and VP151 is $1,795. The maximum
resolution of VP181 is 1600x1200 and VP151 is 1280x1024.
NEC has 15" MultiSync LCD1525X and 18" MultiSync LCD1810X.
They support combining connection of analog and digital and analog
exclusive port. The Hankook computer company, local company,
introduces SlimWin 15D with DF P graphic interface , and a new model
wit h DVI will be introduced in this year.
¢º Future of Digital monitor
Even though digital monitor has lots of advantages, it seems to be far
from us.
In Japan, The TFT LCD monitor takes over 50% of market share in
desktop monitor market, but the analog meth od for VGA interface
takes more percents in it. It may be that the CRT monitor takes
much part, so its effect is still reminded over the industry.
's molecules, direction of light
is defined with alignment of the molecules, and polarizing film
controls direction of the passing light. After applying voltage, the
liquid crystal molecules are aligned in curved angle for passing the
polarizing filter. The applying voltage drives the liqu id crystal as a
shutter of camera for making the light to block or pass the filter.
TFT LCD has cost efficiency due to using low power and glass, and it
doesn' t create noxious frequency.
¢Ñ Sync Signal
- It is a standard signal to give a regular hue signal to monitor.
Basically, the signal is divided into horizontal and vertical Sync
signal. According to the Sync signal, monitor expresses the
normal hue signal by resolution and frequen cy.
¢Ñ Kinds of Sync signal
- Separate: It is a method to delivery the horizontal and vertical
Sync signal to monitor.
- Composite: It is a method to synthesize horizontal and vertical
Sync signal and to delivery the combination signal to monitor.
The signal is separated inner side of the monitor and express the
hue signal on monitor.
- Sync on green: It doesn 't use additional Sync signal line. It is a
method to delivery the signal to monitor by synthesizing the
- It is a degree of difference determined from white (standard) to
own color. As the saturation is bigger, color is getting near to its
own color.
¢Ñ Hue
- Red, green and blue
¢Ñ Vertical frequency
- Monitor repeats the same picture several tens in a second like
fluorescent lamp. The repeating degree to express picture in a
second is called vertical frequency or reflash rate. Unite is Hz.
Example) People can feel the flickering when the light is shown 60
times in a second. It is became a Flicker - free mode by using
over 70Hz of vertical frequency to prevent such happening.
¢Ñ Horizontal frequency
- Horizontal cycle is a taking time to express one horizontal line.
Horizontal frequency divides the horizontal cycle by 1 to express
how many horizontal lines can be express in a second, and use
kHz.
¢Ñ Plug & Play
- It is automatically set up the best picture by exchanging the
information between monitor and computer. Monitor takes the
VESA DOC method (international standard) for plug and play
function.
¢Ñ Resolution
- It is a number of vertical and horizontal dots consisted monitor,
and tells detailed degree of picture. As the resolution is larger,
lots of information can be gotten on the monitor.
- LCD cannot make light itself, so it needs light from external. It is
a light source located in the backside of liquid crystal panel.
¢Ñ Aperture Ratio
- It tells possible area ratio of LCD for displaying information out of
whole screen. As the a perture ratio is larger, picture elements
take more area, so luminosity becomes better.
¢Ñ Viewing Angle
- Contrast ratio is changed by angle of the viewing point. The
changing degree is shown by the viewing angle.
¢Ñ Cross talk
- Signal interruption among picture elements.
¢Ñ Luminance
- It is about the luminosity, and its units are NIT, F/L, Cd/m ©÷etc.
,
¢Ñ Function of Image scaling
- Because 14" and 15" TFT panels are made up of basic pixel
numbers, 1,024x786 mode, a special function is needed to expand
an image in a beeline for watching the whole screen of the SVGA
and VGA.
CONFIDENTIAL
9. Schematic Diagrams
1 CPU Block & Signal Processing Part Schematic Diagram
TO DPTV DIGITAL INPUT TO DPTV
PARALLEL COMM
MCAD(0:7) MCAD(0:7)
MCA(0:19) MCA(0:19)
+3.3V_A
MCAD(5)
MCAD(0)
MCAD(6)
MCAD(7)