CRT Monitors

Today the most wide-spread type monitor this CRT (Cathode Ray Tube) monitors. As can be seen from name, in base all like monitor lies cathode-beam tube, but this literal translation, technically it is correct to speak electronic-beam tube (ELT). Used in this type monitor technology was created much years back and was originally created as special toolbox for measurement of alternating current, more simply, for oscilloscope. The Development to this technologies with reference to to creation monitor has in recent years brought about production all greater on size screen with high quality and under low cost. Today find in shop 14" monitor much in a complicated way, but after all year three four back this was a standard. Today standard are 15" monitors and exists the evident trend aside 17" screen. Soon 17" monitors will become the standard device, particularly in light of the essential price reduction on them, but on horizon already 19" monitors and more.

We shall Consider the principles of the work CRT monitor. CRT or ELT monitor has a glass tube, inwardly which is found vacuum i.e. the whole air is removed. With frontal sides internal part flow tubes is covered лиминофором (Luminofor). As люминофоров for colour ELT are used rather complex compositions on base редкоземельных metal - a yttrium, erbium etc. Lyuminofor this material, which emits the light when bombing his(its) charged particle. We shall Notice that sometimes люминофор name phosphorus, but this not faithfully since люминофор, used in covering CRT nothing have not general with phosphorus. For making the scene in CRT monitor is used electronic gun, which emits the flow an electron VWXbe drafty metallic mask or lattice on internal surface of the glass screen of the monitor, which is covered varicoloured лиминофорными point. The Electrons the cathode and have a negative electric charge. The Flow electron on way to frontal part of tube gets through booster charge, working on principle of the differences potencialov. .В result electrons gain the greater energy, a part from which disperses on phosphorescence люминофора. The Electrons get on люминофорный layer whereupon energy electron is converted in light i.e. flow electron forces the points лиминофора glow. These are a luminous points люминофора form the scene, which you see on your monitor. In general event, in цветном CRT monitor is used three electronic guns, unlike one gun, applicable in monochrome monitor, which presently practically are not produced and little to whom interesting. All we know or heard of that that our eye on the primary colors: red (Red), green (Green) and blue (Blue) and on their combinations, which create the endless number a colour.

Lyuminofornyy layer, covering frontal part electronic-beam tube, consists of very small element (so small that human eye their can not distinguish). These люминофорные elements reproduce the primary colors, practically there are three types of the varicoloured particles, whose colour correspond to the primary colors RGB (thence and name of the group from люминофорных element triads).

Lyuminofor begins to glow, as it was said above, under influence charged electron, which the cathode and are radiated three electronic guns. Each of three guns corresponds to one of the primary colors and sends the bunch an electron on different particles люминофор, whose phosphorescence by primary colors with different intensity is combined and is as a result formed scene with required by colour. For instance if actuate the redden, green and turn blue люминофорные of the particle, that their combination will form the white colour.

Most on itself electronic-beam tube it is not enough for achievement good result, clear that necessary and qualitative controlling electronics. Apropos, exactly difference as controlling electronicses, created by miscellaneous producer, is one of the criterion defining difference between monitor with alike electronic-beam tube. The Ithaca, are repeated: each gun radiates the electronic ray (or flow, or bunch) electron, which influence upon different element люминофорные of the colour (green, red or blue). Understandable that electronic ray, intended for red люминофорных element, can not influence upon люминофор green or blue colour. To obtain such actions is used special mask, whose structure depends on type picture tube from different producers. ELT possible to divide into two classes - an трехлучевые with дельтаобразным by location electronic gun and with planar location electronic gun. щелевые And dark masks are used In these tube though правильнее to say that they all dark. At tubes with planar location electronic gun else name the picture tube with самосведением лучей, since influence of the magnetic field of the Land on three planar located ray practically equally and when change the position of the tube for field of the Land is not required produce the additional regulations.

The Ithaca, the most wide-spread types of the masks this dark, but they be two types: "Shadow Mask" (the dark mask) and "Slot Mask" (щелевая mask).

SHADOW MASK

The Dark mask (shadow mask) this the most wide-spread type of the masks for CRT monitor. The Dark mask consists of metallic net before a part of glass tube with люминофорным слоем. The Holes in metallic net work as sight, exactly this are provided that electronic ray gets only on required люминофорные elements and only in determined area. The Dark mask creates the lattice with uniform point (else named triads), where each such point consists of three люминофрных element primary colors - зеленного, red and blue which glow with different intensity under influence лучей from electronic gun. The Initiation of the phosphorescence люминофорных element with miscellaneous by intensity and комбинирование special image three primary colors allows to get any necessary colour.

The Minimum distance between люминофорными alike colour element is identified dot pitch (or step of the point) and is an index quality scenes. The Step of the point is usually measured in millimeter (the mm). Than importance of the step of the point less, that above quality reproducible on monitor of the scene.

The Dark mask is used in majority modern monitor - Hitachi, Panasonic, Samsung, Daewoo, LG, Nokia, Viewsonic.

SLOT MASK

SCHelevaya mask (slot mask) this technology is broadly used company NEC under name "CromaClear". This decision in practice presents itself combination two technologies described above. In this instance люминофорные elements are located in vertical elliptical cell, but mask is made from vertical line. Practically vertical bands were divided into elliptical cells, which contains the groups from three люминофорных element three primary colors. The Minimum distance between two cells is identified slot pitch (the щелевой step). Than importance slot pitch less, that above quality of the scene on monitor.
Such mask is used, aside from monitor from NEC (where cells elliptical), in monitor Panasonic PanaFlat, LG Flatron and Samsung, and cells are not эллептическими. They have a flat tube, but in them is not used aperture lattice.

There is and one more type tube: однолучевой хроматрон, in which is used "Aperture Grill" (aperture or dark lattice). These tubes become known under name Trinitron and were for the first time submitted for the market company Sony. The Particularity such tube is an using single electronic-beam gun, but colour s the method of the temporary multiplexing. At each moment of time is sent signal of one colour, but electronic bunch moves on corresponding to layer люминофора to account of the making the electric field on that the most aperture lattice (which unlike two other events is not an щелевой by mask).

APERTURE GRILLE

The Aperture lattice (aperture grill) this type of the mask, used by miscellaneous producer in their own technology for production picture tube, carrying name miscellaneous, but having alike essence, for instance technology Trinitron from Sony or Diamondtron from Mitsubishi. This decision does not comprise of itself metallic lattice with hole, as in the event of with dark mask, but has a lattice from vertical line. Instead of point with люминофорными element three primary colors, the aperture lattice contains the series of the threads, consisting of люминофорных element выстроенных in the manner of vertical bands three primary colors. Such system provides high контрастность scenes and get prettier saturation colour that together provides the high quality a monitor with tube on base of this technologies. The Mask applicable in tube of the company Sony (Mitsubishi, ViewSonic), presents itself fine foil, on which процарапаны fine vertical lines. She bes running at horizontal(yh) (one in 15", two in 17", three and more in 21") to delay, shade from which You and see on screen. This delay is used for extinguishing the fluctuations and is identified damper wire. Her(its) is well seen, particularly under light background of the scene on monitor. Some user to these lines in principal do not like, other on the contrary complacent and use their as horizontal straightedge.

The Minimum distance between band люминофора alike colour is identified strip pitch (or at a walk bands) and is measured in millimeter (the mm). Than importance strip pitch less, that above quality of the scene on monitor.

The Aperture lattice is used in monitor from Viewsonic, Radius, Nokia, LG, CTX, in all monitor from SONY and Mitsubishi.
We shall Notice that it is impossible compare the size of the step for tube of the different types: step point (or triads) of the tube with dark mask is measured diagonally while step of the aperture lattice, otherwise named horizontal at a walk point, - on горизонтали. So under alike step point tube with dark mask has greater density point, than tube with aperture lattice. For example, 0.25 mm strip pitch aproximately equivalent 0.27 mm dot pitch.

Both types tube have their own advantage and their own supporter. The Tubes with dark mask give more exact and explicated scene since light gets through holes in mask with clear edge. So monitors with such CRT well to use under intensive and long work with text and small element graphs, in CAD/CAM-applications for instance. The Tubes with aperture lattice have an more open-work mask, she less заслоняет the screen, and allows to get more bright, contrasting scene in saturated colour. The Monitors with such tube well suit for desk publishing systems and the other applications, oriented on work with colour scenes. In CAD system monitors with tube, in which is used aperture lattice, have little liking for not therefore that they worse reproduce the small details, than tubes ch dark mask, but since screen of the monitor of the type Trinitron flat on вертикали and proturberant on горизонтали - i.e. has chosen direction.

Except electronic-beam tube inwardly monitor there is else and controlling electronics, which processes the signal, incoming from видеокарты your PC stright. This electronics must optimize the reinforcement of the signal and control functioning electronic gun, which initiate the phosphorescence люминофора, creating scene on screen. Taken out on screen of the monitor scene looks stable though indeed such is not. The Scene on screen is reproduced as a result of process, in the course of which люминофорные elements miscellaneous colour begin to glow (but then stop to glow) in the following order: left to right and on screen of the monitor from top to bottom. This process occurs by leaps and bounds so we seem that scene stable. In retina our eye scene is kept around 1/20 seconds. Lyuminofor on screen of the monitor glows at the average around 1/10 seconds that what is more time, during which scene is saved in retinas our eye. This means that if point slowly moves on screen, possible see this motion, but when point begins to move in one direction quickly, changing its position at least 20 once at second, our eye do not see the movinging points, but see only even line on screen. The Ability controlling electronicses to force люминофор glow the special image is measured in the manner of widths passband (bandwidth). The Width passband monitor proportional count;calculate;list pixels (each of which corresponds to the minimum of the physical point of the screen of the monitor), which glow for each second.

Certificates TCO and MPR2

For the reason reductions of the risk of the recommendation were designed for health different organization on parameter monitor, following which producers monitor fight for our health. All standards to safety for monitor specify greatly possible importances electric and magnetic flap created by monitor when functioning(working). Practically there is own standards in each developed country, but special popularity all over the world (so formed historically) have conquered the standards, designed in Swedens and the known under names TCO and MPR2.

TCO

TCO (The Swedish Confederation of Professional Employees, Swedish Confederacy Professional Group Worker ), which member are 1.3 million Swedish professional, organizing consists of 19 associations, which work together with purpose of the improvement of the conditions of the work of their own members. These 1.3 mln. members present;introduce;конт)represent broad spectrum worker and serving from state and quotient of the sector of the economy.

TCO at all is not connected with the policy or religion that is one of defining reasons that, allowing unite the different collective member under roof of one organizations. The Teacher, engineers, economists, secretary and nurses only a few from groups, which all together form TCO. This means that TCO reflects the big cut a society that provides her broad support.
This was a quoting from official document TCO. This is because more than 80% employees and worker in Swedens deal with computer so main problem TCO this develop the standards to safety when work with computer i.e. provide its member and all rest safe and комфортное worker place. Except development standard to safety, TCO participates in creation special instrument for testing monitor and computer.

The Standards TCO designed for the reason guarantee the user a computer safe functioning. This standard must correspond to each monitor, sold in Swedens and in Europe. The Recommendations TCO are used producer monitor for making the more qualitative products, which more dangerous for health of the users. The Essence recommendation TCO consists not only in determination of possible importances of the different type of the radiations, but also in determination minimum acceptable parameter monitor, for instance supported permits, intensities of the phosphorescence люминофора, spare to brightness, энергопотребление, шумность and etc. Moreover, except requirements detailed methodses testing monitor happen to in the document TCO.

The Recommendations TCO are used both in Swedens, and in all European country for determination standard parameter, which must correspond to all monitors. In composition designed TCO recommendation today enter three standards: TCO 92, TCO 95 and TCO 99, not difficult guess that numerals mean the year of their acceptance.

The Majority of the measurements during testing on correspondence to standard TCO are conducted on distance 30 refer to frontal from screen, and on distance 50 refer to around monitor. For comparison during testing monitor on correspondence to other standard MPRII all measurements are produced on distance 50 refer to frontal screen and around monitor. This explains that standards TCO more hard, than MPRII.

TCO 92

The Standard TCO 92 was designed solely for monitor and defines the value greatly possible electromagnetic radiations when functioning(working) the monitor, but in the same way installs the standard on functions энергосбережения monitor. Besides, monitor, сертифицированный on TCO 92, must correspond to the standard on энергопотребление NUTEK and correspond to the European standard on fireman and electric safety.

TCO 95

The Standard TCO 92 is calculated only on monitors and their features comparatively electric and magnetic flap, mode энергосбережения and fireman and electric safety. The Standard TCO 95 spreads on the whole personal computer i.e. on monitor, superblock and keyboard and concerns the эргономических a characteristic, radiations (electric and magnetic flap, noise and heats), mode энергосбережения and ecologies (with requirement to obligatory adapting the product and technological process production on factory). We shall Notice that in this instance term "personal computer" comprises of itself workstation, servers, desk and floor computers, as well as computers Macintosh.

The Standard TCO 95 exists alongside with TCO 92 and does not canceal last. The Requirements TCO 95 to electromagnetic radiations monitor are not more hard, than on TCO 92. Apropos as to эргономики, that TCO 95 for the matter of that presents the more strict requirements, than international standard ISO 9241 shall Note that LCD and плазменные monitors also can be сертифицированы on standard TCO 92 and TCO 95, as, however, and portable computers. To word, the mouse does not subject to the сертификации TCO 95. In development of the standard TCO 95 took the joint participation four organizations: TCO, Naturskyddforeinegen, NUTEK and SEMKO AB. Naturskyddforeinegen (The Swedish Society for Nature Conservation) Swedish society of protection of the nature. This is their sign in the manner of flying falcon размещен on allegory TCO 95. Interesting, there was hear the transcription of the name this dear organization. NUTEK (The National Board for Industrial and Technical Development in Sweden) Swedish government agency concerning with studies in the field of энергосбережения and efficient use to energy.

The Company SEMKO AB concerns with testing and сертификацией of the electric products. This is an independent subdivision of the group British Inchcape. SEMKO AB has developed the tests for TCO 95 сертификации and check сертифицированных device.

TCO 99

TCO 99 presents the more hard requirements, than TCO 95 in the following area: эргономика (physical, visual and comfort of the use), energy, radiation (electric and magnetic flap), surrounding ambience and ecology, as well as fireman and electric safety. The Standard TCO 99 spreads on traditional CRT monitors, flat paneling monitors (Flat Panel Displays), portable computers (Laptop and Notebook), superblocks and keyboards. The Specifications TCO 99 contains in itself requirements, taken from standard TCO 95, ISO, IEC and EN, as well as from EC Directive 90/270/EEC and Swedish national standard MPR 1990:8 (MPRII) and from more early recommendation TCO. In development of the standard TCO 99 have took part TCO, Naturskyddsforeningen and and Statens Energimyndighet (The Swedish National Energy Administration, Swedish National Agency on Energy). The Ecological requirements comprise of itself restrictions on presence heavy metal, броминатов and хлоринатов, фреонов (CFC) and chlorinated material inwardly material.
Any product must be prepared to conversion, but producer is obliged to have designed politician on salvaging, which must be performed in each country, in which acts the company.

The Requirements on энергосбережению comprise of itself need that that computer and/or monitor after determined time of the inaction reduced the level of the consumption to energy on one or more steps. At length of time of the reconstruction before operating duty of the consumption to energy, must make the user.

MPR 2

This is one more standard, designed in Swedens, where government and неправительственные organizations much powerfully take care of health of the population of the country. MPRII was designed SWEDAC (The Swedish Board for Technical Accreditation) and defines greatly possible values of the radiation magnetic and electric flap, as well as methods of their measurement. MPRII is based on concepts about that that people live and work in places, where already there is magnetic and electric fields so device such as monitor for computer, must not create electric and magnetic fields, greater than that, which already exist. We shall Notice that standards TCO require the reductions of the radiations electric and magnetic flap from device on so much, insofar this technically possible, outside of dependencies from electric and magnetic flap already existing around us. The Standards TCO жестче, than MPRII. The Standards this well, but user can help the conservation of its health and increase the comfort when work with computer itself. For this exist several recommendations:

• Since monitor this electric device, that always good decision will connect him(it) to wall-plug with earth.
• After enabling during several minutes monitor is powerfully warmed with the result that begin to spread the different chemical separations in the manner of gas, which dangerous for health. So than better is aired out the premises with computer and than more space around monitor, so much the better and безопаснее.
• Much it is important that your monitor and видеоадаптер corresponded to to each other. This guarantees you possibility of the use the optimum permit at radio frequency of the screen of the monitor, but, signifies, your eye will less tire and fall the risk of the deterioration of the vision.
• The Monitors, either as people, get old. Through several years quality scenes can grow worse, in the same way, as can grow worse контрастность and yarkosti

Adjustment and problems

Here is main problems:

• focusing of the scene
• flutter of the scene
• problems with geometry visible on screen of the scene
• problems with even image of the scene on screen

Appear these problems because of complex structure of the monitor, and can be so that even though all electronic components work ok, problem it is impossible avoid change the regulations of the monitor. In practice, majority of the problems appear all because of fault component, problems with calibration, in accordance with discrepancy of the monitor and видеоадаптера and etc. One of the the most most important component of the monitor are an electronic guns, mask and surface with люминофором. We shall Begin with ray electron, which is emitted three guns.
The Guns, which radiate the electrons, on one for each of the primary colors (red, green and blue) send the ray on screen. This ray electron, falling into medium of the screen, forms the circumference while when moving on remaining portions of the screen, ray forms the ellipse with the result that scene is distorted, this process is identified the astigmatism. Moreover problem becomes all more when increase the sizes of the monitor. Of course, no good for our health in this no.

The Other problem, also insecure for health, this flutter of the scene. The Reason of the flutter of the scene is a refresh rate of the screen and time of the remaining phosphorescence люминофора on screen (i.e. that time, during which люминофор continues to glow after hit on it electron). The Refresh rate must correspond to time of the remaining phosphorescence люминофора so that during reproducing the scene on screen, but this process occurs the line for line, люминофор has not lost its brightness before that, as scene will is regenerated, otherwise appears the flutter of the scene. The Effect of the flutter was an usual phenomena in outdated интерлейсных monitor (in them each frame of the scene is formed or by means of even lines, or by means of uneven), on change which came нон интерлейсные monitors (in them each frame of the scene is formed by all lines).

The Other problem this wrong information monitor, which brings about размытию and нечеткости scenes. Three rays electron, emitted corresponding to gun must exactly reconverge on one pixel and force his(its) glow. If this does not occur, basically because of problems with calibration, scene will нерезким in these point.

Else one problem is нечеткость scenes on border of the screen. Appears this problem because of that that electronic guns not exactly наведены and as a result they can not direct the electrons on necessary pixel or glow begins simply not that pixel. For decision of these problems to producers use the declining system, which directs the rays an electron. Since electrons must reach not only central part of screen, but also all rest, but at distance before the centre of the screen less, than before edge. And difference that more, than прямее screen. But solves all these problems declining system. If device declining systems are wrong calibrated, that as a result can appear the problems in the manner of garbling the scene, for instance "barrel distortion" or "pincushion" (подушкообразность or бочкообразность), when borders of the scene искривляются toward outward from scene or on direction in internal subimage. Possible also garbling the type "trapezium distortion" or "trapezoid", when lateral borders are bent and tend the slopes to one point i.e. scene has a form to trapezoids. Sometimes like distortion can appear and as a result excessively long use the monitor in consequence of which scene mildly turns round for their own axises.
Enough often meeting problem are colour or dark heel, which suddenly appear on screen of the monitor. Moreover else yesterday all were fine, but today on screen rainbow. In this case, sooner whole, has occurred the magnetization of the dark mask (or aperture lattice or щелевой of the mask) of the tube of the monitor. The Magnetization occurs under influence by magnetic flap: natural (we shall say the magnetic anomaly) or created person (other monitor, acoustic rows, transformer). Moreover, magnetization can appear and as a result even short functioning(working) the monitor in non-standard position (the screen downwards or upwards or on side). This is because in monitor built-in system to compensations of the influence by magnetic flap of the Land, which under non-standard position of the monitor only intensify this influence. Because of magnetization can be broken information of the monitor and appear geometric distortion.

For degaussing of the tube practically in all modern monitor is provided special sidebar, on which is missed current at moment of the power-up. At monitor has, as a rule, and additional button (or point OSD menu) of the forced degaussing (Degauss). If after enabling you have found the heel on screen, that two times press the button of the degaussing. If heel disappeared not completely, that makes sure that monitor cost(stand)s in standard position, and through 25-30 minutes repeat the process of the degaussing.
If in your monitor is not provided such functions, that simply several times includes-switch off the monitor, making pause during several minutes.

Here cost(stand)s to add the important detail. The Built-in degaussing is included only when presenting the power supply i.e. after monitor was обесточен completely. That brings about interesting fact - a blocks ATX have a no connector for power supply the monitor. А under constantly included monitor (if his(its) not обесточивать, but so all and enter) degaussing does not work. So about such nuance cost(stand)s to remember. We shall Note that such problems no beside many modern models monitor, since they are degaussed when turning from "Stanby" in normal mode i.e. full unhooking the power supply is not required.

If all degauss the screen of the monitor not to manage, that you should apply to service centre, since use the do-it-yourself methods can bring about pitiful result.

Besides, follows to note that many problems, appearing when use the monitor, appear because of видеоадаптера computer or because of interface cable between monitor and video card. Occasionly, what this was not shown funny, but some problems with monitor can be solved as a result simple переворачивания interface cable or as a result of installation new driver видеоадаптера or after installation of the other permit or other refresh rate of the screen.

The Ithaca, in view of that that monitor is a device, beside which can appear the problems, negativly influencing upon комфортность your work for computer then at choice of the new monitor follows to show a preference as possible more qualitative monitor, to the best advantage answerring your necessity. Depending on type and marks of the monitor set functional tuning, allowing solve the part or majority of the problems, can greatly differ so at choice of the monitor make sure that he has a sufficient set changeable tuning, which will allow you to solve the part of problems by itself, without needing referencing in service centre. More so that even though when buying beside monitor were absent the defect, they can be shown in consequence.

Author: А. V. Savin It Is Added: 30.04.2007