14 240PW9LCD
FAQs (Frequently Asked Questions)Q:WhatisaUSBhub?
A:A USB hub provides additionalconnections to the UniversalSerial Bus.
Ahub's ups tream port connects ahu b to the host, usuall y a PC. Multiple
downstreamports in ahub allows connectiont o anotherhub or device,
such as a USB keyboard, camera or print er.
LCD Panel Technology
Q:Wh at is a Liquid Crystal Display?
A: ALiquid Cr ystal Display (LCD) is an optic ald evice that is commonly
used to display ASCII characters and im ages on digital items such as
watches,calculators,portable game consoles,etc. LCD is the technology
used for displays in notebooks and ot her small computers. Like
light-emitting diode and g as-plasma technol ogies, LCD allows dis plays to
bemuch thinner than cathoder ayt ube(CRT) technology.LCD c onsumes
much less power than LED and gas-dis plays because it works on th e
principleof blockinglight rather than emitting it.
Q:Wh at differentiates passive matr ix LCDs from active matrix
LCDs?
A:An LCD is made with either a passive matri x or an active matrix
display grid. An active matrix has a transis tor located at each pixel
intersection, requiring l ess current to cont rol the luminance of a pixel. For
thisr eason, the current in an active matrix dis play can be switch ed on
and off more frequently, impr oving the screen r efresh time (your m ouse
pointer will appear to move mor es moothly across the screen, f or
example). The passive matrix LCD h as a grid of conductors with pixels
located at each intersect ion in the grid.
Q:Wh at are the advantages of TFT LCD compar ed with CRT?
A: Ina C RTmon itor, a gun shoots electrons and general li ght byc olliding
polarized electrons onfl uorescent glass. T herefore, CRT monitors
basically operate with an analog RG Bs ignal. ATFT LCD m onitor is a
devicethat displaysan input image by operatinga liquid crystal panel.
TheTF T has a fundamentall yd ifferent structure t han a CRT: Each cell
has an active matrix structure and in dependent active element s.A TFT
LCDh as two glass panels andt he space between t hem is filled wit h liquid
crystal. When each cell is connect ed with electrodes and impressed wi th
voltage, the molecular struct ure of the liquid crystal is altered and controls
the amount of inlet lighting to display im ages.A TFT LCD has sever al
advantages over a CRT, since it can be very thin and no flic kering occurs
because it does not us e the scanning meth od.
Q:Why is vertical frequency of 60Hz optimal for an LC D monitor?
A:U nlike a CRT monitor, the T FT LCD panel has a fi xed resolution. For
example, an XGA monitor has 1024x3 (R, G, B) x 768 pixels an d a higher
resolution may not be available with out additional software processi ng.
Thepanel is designed to optimizethe display for a 65MHz dot clock, one
ofth e standards for XGA displ ays. Since the vert ical/horizontal fr equency
forth isd ot clock is 60Hz/48kHz, th e optimum frequency f orthis monitor is
60Hz.
Q:Wh at kindof w ide-angle technology is available? How does it
work?
A:T heT FT LCD panel is an element that controls/d isplays the inlet of a
backlight using the dual- refraction of a liqu id crystal. Using th e property
thatt he projection of inlet light refr acts toward the major axis of the liqui d
element, it controls the direction ofi nlet light and displays it. Sinc eth e
refractionratioof inlet light on liquidcrystal varies withthe inlet angle of
theli ght, the viewing angle of a TFT is much narr ower than that of a CRT.
Usually, the viewing angle r efers to the point where the contrast ratio n is
10.M any ways to widen the viewing an gle are currently being develo ped
andt he most common ap proach is to use a wid e viewing angle fil m,
which widens the viewing angle b yvar ying the refraction ratio. IPS (In
Plane Switching) or MVA (Multi Vertic alA ligned) is also us ed to give a
wider viewing angle.
Q:Why i sth ereno f licker on an LCD Monitor?
A:Technic ally speaking, LCDs do flicker, but the caus e ofth e
phenomenon is different from that of a CRT mon itor -- and it has no
impact of the ease of viewing. Flicker ing in an LCD monitor relates to
usually undetectable lum inance caused by th e difference between
positive and negative voltage. On th e other hand, CRT flickering that c an
irritate the human eye occurs when th e on/off action of the fluorescen t
object becomes visibl e. Since the reaction s peed of liquid cr ystal in an
LCDp anel is much slower, th is troublesome form off lickering is not
present in an LCD display.
Q:Why isan L CD monitor virtually low of Electro Magnetic
Interference?
A:U nlike a CRT,an LC D monitor does not have key parts that gener ate
Electro Magnetic Interferenc e, especially magnetic fields .Als o, since an
LCDdisplay utilizesrelatively low power,its power supply is extremely
quiet.
Ergonomics,Ecology and Safety Standards
Q:Wh at is the CE mark?
A:T he CE (Conformit é Européenne) mark isr equired to be displ ayed on
allr egulated products off ered for sale on the E uropean market. This 'CE'
mark means that a product c omplies with the relev ant European Direct ive.
AEurop ean Directive is a Eur opean 'Law' that rel ates to health, saf ety,
environment and consumer pr otection, much the same as the U.S.
National Electrical Code andU L Standards.
Q:Does th e LCD monitor conform to general safety standards?
A: Yes.Philips LCD monitors confor m to the guidelines ofMP R-II and
TCO 99/03 standards for t he control of radiat ion, electromagnetic waves,
energyreduction, electricalsafety in the work environmentand
recyclab ility. The s pecific ation pa ge provi des deta iled dat a on safet y
standards.
Q:After I changenew PC, I found this informationon screen, how
canI do ?
A: Because you activate Th eft Deterrence functi on in SmartControl II.
Please contact IT manager orP hilips Service Cent er.