cathode-ray tube display screens made in china

A cathode-ray tube (CRT) is a vacuum tube containing one or more electron guns, which emit electron beams that are manipulated to display images on a phosphorescent screen.waveforms (oscilloscope), pictures (television set, computer monitor), radar targets, or other phenomena. A CRT on a television set is commonly called a picture tube. CRTs have also been used as memory devices, in which case the screen is not intended to be visible to an observer. The term

In CRT television sets and computer monitors, the entire front area of the tube is scanned repeatedly and systematically in a fixed pattern called a raster. In color devices, an image is produced by controlling the intensity of each of three electron beams, one for each additive primary color (red, green, and blue) with a video signal as a reference.magnetic deflection, using a deflection yoke. Electrostatic deflection is commonly used in oscilloscopes.

Since the mid-late 2000"s, CRTs have been superseded by flat-panel display technologies such as LCD, plasma display, and OLED displays which are cheaper to manufacture and run, as well as significantly lighter and less bulky. Flat-panel displays can also be made in very large sizes whereas 40 in (100 cm) to 45 in (110 cm)

Cathode rays were discovered by Julius Plücker and Johann Wilhelm Hittorf.cathode (negative electrode) which could cast shadows on the glowing wall of the tube, indicating the rays were traveling in straight lines. In 1890, Arthur Schuster demonstrated cathode rays could be deflected by electric fields, and William Crookes showed they could be deflected by magnetic fields. In 1897, J. J. Thomson succeeded in measuring the charge-mass-ratio of cathode rays, showing that they consisted of negatively charged particles smaller than atoms, the first "subatomic particles", which had already been named George Johnstone Stoney in 1891. The earliest version of the CRT was known as the "Braun tube", invented by the German physicist Ferdinand Braun in 1897.cold-cathode diode, a modification of the Crookes tube with a phosphor-coated screen. Braun was the first to conceive the use of a CRT as a display device.

The first cathode-ray tube to use a hot cathode was developed by John Bertrand Johnson (who gave his name to the term Johnson noise) and Harry Weiner Weinhart of Western Electric, and became a commercial product in 1922.

In 1926, Kenjiro Takayanagi demonstrated a CRT television receiver with a mechanical video camera that received images with a 40-line resolution.Philo Farnsworth created a television prototype.Vladimir K. Zworykin.: 84 RCA was granted a trademark for the term (for its cathode-ray tube) in 1932; it voluntarily released the term to the public domain in 1950.

In 1947, the cathode-ray tube amusement device, the earliest known interactive electronic game as well as the first to incorporate a cathode-ray tube screen, was created.

In the mid-2000s, Canon and Sony presented the surface-conduction electron-emitter display and field-emission displays, respectively. They both were flat-panel displays that had one (SED) or several (FED) electron emitters per subpixel in place of electron guns. The electron emitters were placed on a sheet of glass and the electrons were accelerated to a nearby sheet of glass with phosphors using an anode voltage. The electrons were not focused, making each subpixel essentially a flood beam CRT. They were never put into mass production as LCD technology was significantly cheaper, eliminating the market for such displays.

Beginning in the late 90s to the early 2000s, CRTs began to be replaced with LCDs, starting first with computer monitors smaller than 15 inches in size,Hitachi in 2001,Flat-panel displays dropped in price and started significantly displacing cathode-ray tubes in the 2000s. LCD monitor sales began exceeding those of CRTs in 2003–2004

Despite being a mainstay of display technology for decades, CRT-based computer monitors and televisions are now virtually a dead technology. Demand for CRT screens dropped in the late 2000s.

A popular consumer usage of CRTs is for retrogaming. Some games are impossible to play without CRT display hardware, and some games play better. Reasons for this include:

The design of the high voltage power supply in a product using a CRT has an influence in the amount of x-rays emitted by the CRT. The amount of emitted x-rays increases with both higher voltages and currents. If the product such as a TV set uses an unregulated high voltage power supply, meaning that anode and focus voltage go down with increasing electron current when displaying a bright image, the amount of emitted x-rays is as its highest when the CRT is displaying a moderately bright images, since when displaying dark or bright images, the higher anode voltage counteracts the lower electron beam current and vice versa respectively. The high voltage regulator and rectifier vacuum tubes in some old CRT TV sets may also emit x-rays.

Since it is a hot cathode, it is prone to cathode poisoning, which is the formation of a positive ion layer that prevents the cathode from emitting electrons, reducing image brightness significantly or completely and causing focus and intensity to be affected by the frequency of the video signal preventing detailed images from being displayed by the CRT. The positive ions come from leftover air molecules inside the CRT or from the cathode itself

Burn-in is when images are physically "burned" into the screen of the CRT; this occurs due to degradation of the phosphors due to prolonged electron bombardment of the phosphors, and happens when a fixed image or logo is left for too long on the screen, causing it to appear as a "ghost" image or, in severe cases, also when the CRT is off. To counter this, screensavers were used in computers to minimize burn-in.

Various phosphors are available depending upon the needs of the measurement or display application. The brightness, color, and persistence of the illumination depends upon the type of phosphor used on the CRT screen. Phosphors are available with persistences ranging from less than one microsecond to several seconds.

Doming is a phenomenon found on some CRT televisions in which parts of the shadow mask become heated. In televisions that exhibit this behavior, it tends to occur in high-contrast scenes in which there is a largely dark scene with one or more localized bright spots. As the electron beam hits the shadow mask in these areas it heats unevenly. The shadow mask warps due to the heat differences, which causes the electron gun to hit the wrong colored phosphors and incorrect colors to be displayed in the affected area.

Aperture grille screens are brighter since they allow more electrons through, but they require support wires. They are also more resistant to warping.

CRT monitors can still outperform LCD and OLED monitors in input lag, as there is no signal processing between the CRT and the display connector of the monitor, since CRT monitors often use VGA which provides an analog signal that can be fed to a CRT directly. Video cards designed for use with CRTs may have a RAMDAC to generate the analog signals needed by the CRT.multisyncing.

Picture tube CRTs have overscan, meaning the actual edges of the image are not shown; this is deliberate to allow for adjustment variations between CRT TVs, preventing the ragged edges (due to blooming) of the image from being shown on screen. The shadow mask may have grooves that reflect away the electrons that do not hit the screen due to overscan.

A shadow mask tube uses a metal plate with tiny holes, typically in a delta configuration, placed so that the electron beam only illuminates the correct phosphors on the face of the tube;aperture grille of tensioned vertical wires to achieve the same result.

Due to limitations in the dimensional precision with which CRTs can be manufactured economically, it has not been practically possible to build color CRTs in which three electron beams could be aligned to hit phosphors of respective color in acceptable coordination, solely on the basis of the geometric configuration of the electron gun axes and gun aperture positions, shadow mask apertures, etc. The shadow mask ensures that one beam will only hit spots of certain colors of phosphors, but minute variations in physical alignment of the internal parts among individual CRTs will cause variations in the exact alignment of the beams through the shadow mask, allowing some electrons from, for example, the red beam to hit, say, blue phosphors, unless some individual compensation is made for the variance among individual tubes.

The solution to the static convergence and purity problems is a set of color alignment ring magnets installed around the neck of the CRT.magnetic fields parallel to the planes of the magnets, which are perpendicular to the electron gun axes. Often, one ring has two poles, another has 4, and the remaining ring has 6 poles.vector can be fully and freely adjusted (in both direction and magnitude). By rotating a pair of magnets relative to each other, their relative field alignment can be varied, adjusting the effective field strength of the pair. (As they rotate relative to each other, each magnet"s field can be considered to have two opposing components at right angles, and these four components [two each for two magnets] form two pairs, one pair reinforcing each other and the other pair opposing and canceling each other. Rotating away from alignment, the magnets" mutually reinforcing field components decrease as they are traded for increasing opposed, mutually cancelling components.) By rotating a pair of magnets together, preserving the relative angle between them, the direction of their collective magnetic field can be varied. Overall, adjusting all of the convergence/purity magnets allows a finely tuned slight electron beam deflection or lateral offset to be applied, which compensates for minor static convergence and purity errors intrinsic to the uncalibrated tube. Once set, these magnets are usually glued in place, but normally they can be freed and readjusted in the field (e.g. by a TV repair shop) if necessary.

The convergence signal may instead be a sawtooth signal with a slight sine wave appearance, the sine wave part is created using a capacitor in series with each deflection coil. In this case, the convergence signal is used to drive the deflection coils. The sine wave part of the signal causes the electron beam to move more slowly near the edges of the screen. The capacitors used to create the convergence signal are known as the s-capacitors. This type of convergence is necessary due to the high deflection angles and flat screens of many CRT computer monitors. The value of the s-capacitors must be chosen based on the scan rate of the CRT, so multi-syncing monitors must have different sets of s-capacitors, one for each refresh rate.

Dynamic color convergence and purity are one of the main reasons why until late in their history, CRTs were long-necked (deep) and had biaxially curved faces; these geometric design characteristics are necessary for intrinsic passive dynamic color convergence and purity. Only starting around the 1990s did sophisticated active dynamic convergence compensation circuits become available that made short-necked and flat-faced CRTs workable. These active compensation circuits use the deflection yoke to finely adjust beam deflection according to the beam target location. The same techniques (and major circuit components) also make possible the adjustment of display image rotation, skew, and other complex raster geometry parameters through electronics under user control.

Color CRT displays in television sets and computer monitors often have a built-in degaussing (demagnetizing) coil mounted around the perimeter of the CRT face. Upon power-up of the CRT display, the degaussing circuit produces a brief, alternating current through the coil which fades to zero over a few seconds, producing a decaying alternating magnetic field from the coil. This degaussing field is strong enough to remove shadow mask magnetization in most cases, maintaining color purity.deform (bend) the shadow mask, causing a permanent color distortion on the display which looks very similar to a magnetization effect.

Dot pitch defines the maximum resolution of the display, assuming delta-gun CRTs. In these, as the scanned resolution approaches the dot pitch resolution, moiré appears, as the detail being displayed is finer than what the shadow mask can render.

Beam-index tubes, also known as Uniray, Apple CRT or Indextron,Philco to create a color CRT without a shadow mask, eliminating convergence and purity problems, and allowing for shallower CRTs with higher deflection angles.

Flat CRTs are those with a flat screen. Despite having a flat screen, they may not be completely flat, especially on the inside, instead having a greatly increased curvature. A notable exception is the LG Flatron (made by LG.Philips Displays, later LP Displays) which is truly flat on the outside and inside, but has a bonded glass pane on the screen with a tensioned rim band to provide implosion protection. Such completely flat CRTs were first introduced by Zenith in 1986, and used

flat tensioned shadow masks, where the shadow mask is held under tension, providing increased resistance to blooming.TV80, and in many Sony Watchmans were flat in that they were not deep and their front screens were flat, but their electron guns were put to a side of the screen.

Radar CRTs such as the 7JP4 had a circular screen and scanned the beam from the center outwards. The screen often had two colors, often a bright short persistence color that only appeared as the beam scanned the display and a long persistence phosphor afterglow. When the beam strikes the phosphor, the phosphor brightly illuminates, and when the beam leaves, the dimmer long persistence afterglow would remain lit where the beam struck the phosphor, alongside the radar targets that were "written" by the beam, until the beam re-struck the phosphor.

In oscilloscope CRTs, electrostatic deflection is used, rather than the magnetic deflection commonly used with television and other large CRTs. The beam is deflected horizontally by applying an electric field between a pair of plates to its left and right, and vertically by applying an electric field to plates above and below. Televisions use magnetic rather than electrostatic deflection because the deflection plates obstruct the beam when the deflection angle is as large as is required for tubes that are relatively short for their size. Some Oscilloscope CRTs incorporate post deflection anodes (PDAs) that are spiral-shaped to ensure even anode potential across the CRT and operate at up to 15,000 volts. In PDA CRTs the electron beam is deflected before it is accelerated, improving sensitivity and legibility, specially when analyzing voltage pulses with short duty cycles.

When displaying fast one-shot events, the electron beam must deflect very quickly, with few electrons impinging on the screen, leading to a faint or invisible image on the display. Oscilloscope CRTs designed for very fast signals can give a brighter display by passing the electron beam through a micro-channel plate just before it reaches the screen. Through the phenomenon of secondary emission, this plate multiplies the number of electrons reaching the phosphor screen, giving a significant improvement in writing rate (brightness) and improved sensitivity and spot size as well.

Most oscilloscopes have a graticule as part of the visual display, to facilitate measurements. The graticule may be permanently marked inside the face of the CRT, or it may be a transparent external plate made of glass or acrylic plastic. An internal graticule eliminates parallax error, but cannot be changed to accommodate different types of measurements.

Where a single brief event is monitored by an oscilloscope, such an event will be displayed by a conventional tube only while it actually occurs. The use of a long persistence phosphor may allow the image to be observed after the event, but only for a few seconds at best. This limitation can be overcome by the use of a direct view storage cathode-ray tube (storage tube). A storage tube will continue to display the event after it has occurred until such time as it is erased. A storage tube is similar to a conventional tube except that it is equipped with a metal grid coated with a dielectric layer located immediately behind the phosphor screen. An externally applied voltage to the mesh initially ensures that the whole mesh is at a constant potential. This mesh is constantly exposed to a low velocity electron beam from a "flood gun" which operates independently of the main gun. This flood gun is not deflected like the main gun but constantly "illuminates" the whole of the storage mesh. The initial charge on the storage mesh is such as to repel the electrons from the flood gun which are prevented from striking the phosphor screen.

When the main electron gun writes an image to the screen, the energy in the main beam is sufficient to create a "potential relief" on the storage mesh. The areas where this relief is created no longer repel the electrons from the flood gun which now pass through the mesh and illuminate the phosphor screen. Consequently, the image that was briefly traced out by the main gun continues to be displayed after it has occurred. The image can be "erased" by resupplying the external voltage to the mesh restoring its constant potential. The time for which the image can be displayed was limited because, in practice, the flood gun slowly neutralises the charge on the storage mesh. One way of allowing the image to be retained for longer is temporarily to turn off the flood gun. It is then possible for the image to be retained for several days. The majority of storage tubes allow for a lower voltage to be applied to the storage mesh which slowly restores the initial charge state. By varying this voltage a variable persistence is obtained. Turning off the flood gun and the voltage supply to the storage mesh allows such a tube to operate as a conventional oscilloscope tube.

The Williams tube or Williams-Kilburn tube was a cathode-ray tube used to electronically store binary data. It was used in computers of the 1940s as a random-access digital storage device. In contrast to other CRTs in this article, the Williams tube was not a display device, and in fact could not be viewed since a metal plate covered its screen.

In some vacuum tube radio sets, a "Magic Eye" or "Tuning Eye" tube was provided to assist in tuning the receiver. Tuning would be adjusted until the width of a radial shadow was minimized. This was used instead of a more expensive electromechanical meter, which later came to be used on higher-end tuners when transistor sets lacked the high voltage required to drive the device.

Some displays for early computers (those that needed to display more text than was practical using vectors, or that required high speed for photographic output) used Charactron CRTs. These incorporate a perforated metal character mask (stencil), which shapes a wide electron beam to form a character on the screen. The system selects a character on the mask using one set of deflection circuits, but that causes the extruded beam to be aimed off-axis, so a second set of deflection plates has to re-aim the beam so it is headed toward the center of the screen. A third set of plates places the character wherever required. The beam is unblanked (turned on) briefly to draw the character at that position. Graphics could be drawn by selecting the position on the mask corresponding to the code for a space (in practice, they were simply not drawn), which had a small round hole in the center; this effectively disabled the character mask, and the system reverted to regular vector behavior. Charactrons had exceptionally long necks, because of the need for three deflection systems.

Nimo was the trademark of a family of small specialised CRTs manufactured by Industrial Electronic Engineers. These had 10 electron guns which produced electron beams in the form of digits in a manner similar to that of the charactron. The tubes were either simple single-digit displays or more complex 4- or 6- digit displays produced by means of a suitable magnetic deflection system. Having little of the complexities of a standard CRT, the tube required a relatively simple driving circuit, and as the image was projected on the glass face, it provided a much wider viewing angle than competitive types (e.g., nixie tubes).

Flood-beam CRTs are small tubes that are arranged as pixels for large video walls like Jumbotrons. The first screen using this technology (called Diamond Vision by Mitsubishi Electric) was introduced by Mitsubishi Electric for the 1980 Major League Baseball All-Star Game. It differs from a normal CRT in that the electron gun within does not produce a focused controllable beam. Instead, electrons are sprayed in a wide cone across the entire front of the phosphor screen, basically making each unit act as a single light bulb.light-emitting diode displays. Unfocused and undeflected CRTs were used as grid-controlled stroboscope lamps since 1958.Electron-stimulated luminescence (ESL) lamps, which use the same operating principle, were released in 2011.

In the late 1990s and early 2000s Philips Research Laboratories experimented with a type of thin CRT known as the Zeus display, which contained CRT-like functionality in a flat-panel display.

Some CRT manufacturers, both LG.Philips Displays (later LP Displays) and Samsung SDI, innovated CRT technology by creating a slimmer tube. Slimmer CRT had the trade names Superslim,

At low refresh rates (60 Hz and below), the periodic scanning of the display may produce a flicker that some people perceive more easily than others, especially when viewed with peripheral vision. Flicker is commonly associated with CRT as most televisions run at 50 Hz (PAL) or 60 Hz (NTSC), although there are some 100 Hz PAL televisions that are flicker-free. Typically only low-end monitors run at such low frequencies, with most computer monitors supporting at least 75 Hz and high-end monitors capable of 100 Hz or more to eliminate any perception of flicker.sonar or radar may have long persistence phosphor and are thus flicker free. If the persistence is too long on a video display, moving images will be blurred.

This problem does not occur on 100/120 Hz TVs and on non-CGA (Color Graphics Adapter) computer displays, because they use much higher horizontal scanning frequencies that produce sound which is inaudible to humans (22 kHz to over 100 kHz).

High vacuum inside glass-walled cathode-ray tubes permits electron beams to fly freely—without colliding into molecules of air or other gas. If the glass is damaged, atmospheric pressure can collapse the vacuum tube into dangerous fragments which accelerate inward and then spray at high speed in all directions. Although modern cathode-ray tubes used in televisions and computer displays have epoxy-bonded face-plates or other measures to prevent shattering of the envelope, CRTs must be handled carefully to avoid personal injury.

Under some circumstances, the signal radiated from the electron guns, scanning circuitry, and associated wiring of a CRT can be captured remotely and used to reconstruct what is shown on the CRT using a process called Van Eck phreaking.TEMPEST shielding can mitigate this effect. Such radiation of a potentially exploitable signal, however, occurs also with other display technologies

As electronic waste, CRTs are considered one of the hardest types to recycle.phosphors, both of which are necessary for the display. There are several companies in the United States that charge a small fee to collect CRTs, then subsidize their labor by selling the harvested copper, wire, and printed circuit boards. The United States Environmental Protection Agency (EPA) includes discarded CRT monitors in its category of "hazardous household waste"

Musgraves, J. David; Hu, Juejun; Calvez, Laurent (8 November 2019). "Cathod Ray-Tube Design". Springer Handbook of Glass. Springer Nature. p. 1367. ISBN 978-3-319-93728-1.

Martin, André (1986). "Cathode Ray Tubes for Industrial and Military Applications". In Hawkes, Peter (ed.). Advances in Electronics and Electron Physics. Vol. 67. Academic Press. pp. 183–328. doi:10.1016/S0065-2539(08)60331-5. ISBN 9780080577333. Evidence for the existence of "cathode-rays" was first found by Plücker and Hittorf ...

Lehrer, Norman, H. (1985). "The Challenge of the Cathode-Ray Tube". In Tannas, Lawrence E. Jr. (ed.). Flat-Panel Displays and CRTs. New York: Van Nostrand Reinhold Company Inc. pp. 138–176. doi:10.1007/978-94-011-7062-8_6. ISBN 978-94-011-7062-8.

Harland, Doug. "Picture Tubes: Motorola Prototype Rectangular Color CRT". www.earlytelevision.org. Early Television Museum. Retrieved 11 November 2021.

Keller, Peter A. (October 2007). "Tektronic CRT History: Part 5: The hybrid years: 1961-64" (PDF). The Tube Collector. Vol. 9, no. 5. Ashland, Oregon: Tube Collectors Association. p. 5. Retrieved 11 November 2021.

Mekeel, Tim; Knowles, Laura (12 September 2013). "RCA pioneers remember making the first color TV tube". LancasterOnline. LNP Media Group Inc. Archived from the original on 4 August 2021. Retrieved 11 November 2021.

US 3440080, Tamura, Michio & Nakamura, Mitsuyoshi, "Cathode ray tube color screen and method of producing same", published 1969-04-22, assigned to Sony Corp.

Warren, Rich (30 September 1991). "TV makers tuning in to flat screens to help round out sales". chicagotribune.com. Chicago Tribune. Retrieved 11 November 2021.

EP 0088122B1, "Large metal cone cathode ray tubes, and envelopes therefor" calls it faceplate US 20040032200A1, "CRT having a contrast enhancing exterior coating and method of manufacturing the same" also calls it faceplate US 20060132019A1, "Funnel for use in a cathode ray tube"

Ha, Kuedong; Shin, Soon-Cheol; Kim, Do-Nyun; Lee, Kue-Hong; Kim, Jeong-Hoon (2006). "Development of a 32-in. slim CRT with 125° deflection". Journal of the Society for Information Display. 14 (1): 65. doi:10.1889/1.2166838. S2CID 62697886.

"GW-12.10-130: NEW APPROACH TO CATHODE RAY TUBE (CRT) RECYCLING" (PDF). www.glass-ts.com. 2003. Archived from the original (PDF) on 13 November 2020. Retrieved 11 December 2020.

Lee, Ching-Hwa; Hsi, Chi-Shiung (1 January 2002). "Recycling of Scrap Cathode Ray Tubes". Environmental Science & Technology. 36 (1): 69–75. Bibcode:2002EnST...36...69L. doi:10.1021/es010517q. PMID 11811492.

Xu, Qingbo; Li, Guangming; He, Wenzhi; Huang, Juwen; Shi, Xiang (August 2012). "Cathode ray tube (CRT) recycling: Current capabilities in China and research progress". Waste Management. 32 (8): 1566–1574. doi:10.1016/j.wasman.2012.03.009. PMID 22542858.

"TV and Monitor CRT (Picture Tube) Information". repairfaq.cis.upenn.edu. Archived from the original on 22 November 2020. Retrieved 8 December 2020. 90 degrees in monitors, 110 in TVs

Ozawa, Lyuji (15 January 2002). "Electron flow route at phosphor screens in CRTs". Materials Chemistry and Physics. 73 (2): 144–150. doi:10.1016/s0254-0584(01)00360-1.

Gassler, Gerhard (2016). "Cathode Ray Tubes (CRTS)". Handbook of Visual Display Technology. pp. 1595–1607. doi:10.1007/978-3-319-14346-0_70. ISBN 978-3-319-14345-3.

den Engelsen, Daniel; Ferrario, Bruno (1 March 2004). "Gettering by Ba films in color cathode ray tubes". Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena. 22 (2): 809–817. Bibcode:2004JVSTB..22..809D. doi:10.1116/1.1689973.

DeBoer, Clint. "Cathode Ray Tube (CRT) Direct View and Rear Projection TVs". Audioholics Home Theater, HDTV, Receivers, Speakers, Blu-ray Reviews and News.

US 7138755B2, "Color picture tube apparatus having beam velocity modulation coils overlapping with convergence and purity unit and ring shaped ferrite core"

Ozeroff, M. J.; Thornton, W. A.; Young, J. R. (29 April 1953). Proposed Improvement in Evacuation Technique for TV Tubes (PDF) (Report). Archived (PDF) from the original on 15 February 2020.

Goetz, D.; Schaefer, G.; Rufus, J. (4 June 1998). "The use of turbomolecular pumps in television tube production". Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films. 5 (4): 2421. doi:10.1116/1.574467.

Yin, Xiaofei; Wu, Yufeng; Tian, Xiangmiao; Yu, Jiamei; Zhang, Yi-Nan; Zuo, Tieyong (5 December 2016). "Green Recovery of Rare Earths from Waste Cathode Ray Tube Phosphors: Oxidative Leaching and Kinetic Aspects". ACS Sustainable Chemistry & Engineering. 4 (12): 7080–7089. doi:10.1021/acssuschemeng.6b01965.

"Implementing Display Standards in Modern Video Display Technologies" (PDF). www.cinemaquestinc.com. Archived (PDF) from the original on 14 June 2016. Retrieved 11 December 2020.

Martindale, Jon (17 September 2019). "New Report States CRT Monitors Are Still Better Than Modern Gaming Displays". Digital Trends. Retrieved 11 December 2020.

Bowie, R.M. (December 1948). "The Negative-Ion Blemish in a Cathode-Ray Tube and Its Elimination". Proceedings of the IRE. 36 (12): 1482–1486. doi:10.1109/JRPROC.1948.232950. S2CID 51635920.

Dudding, R.W. (1951). "Aluminium backed screens for cathode ray tubes". Journal of the British Institution of Radio Engineers. 11 (10): 455–462. doi:10.1049/jbire.1951.0057.

Ohno, K.; Kusunoki, T. (5 August 2010). "ChemInform Abstract: Effect of Ultrafine Pigment Color Filters on Cathode Ray Tube Brightness, Contrast, and Color Purity". ChemInform. 27 (33): no. doi:10.1002/chin.199633002.

Abend, U.; Kunz, H. -J.; Wandmacher, J. (1 January 1981). "A vector graphic CRT display system". Behavior Research Methods & Instrumentation. 13 (1): 46–50. doi:S2CID 62692534.

"Futaba TL-3508XA "Jumbotron" Display". The Vintage Technology Association: Military Industrial Electronics Research Preservation. The Vintage Technology Association. 11 March 2010. Retrieved 19 December 2014.

"CK1366 CK1367 Printer-type cathode ray tube data sheet" (PDF). Raytheon Company. 1 November 1960. Archived from the original (PDF) on 19 December 2019. Retrieved 29 July 2017.

"CK1368 CK1369 Printer-type cathode ray tube data sheet" (PDF). Raytheon Company. 1 November 1960. Archived from the original (PDF) on 19 December 2019. Retrieved 29 July 2017.

Lambert, N.; Montie, E.A.; Baller, T.S.; Van Gorkom, G.G.P.; Hendriks, B.H.W.; Trompenaars, P.H.F.; De Zwart, S.T. (1996). "Transport and extraction in Zeus displays". Philips Journal of Research. 50 (3–4): 295. doi:10.1016/S0165-5817(97)84677-3.

Doyle, T.; Van Asma, C.; McCormack, J.; De Greef, D.; Haighton, V.; Heijnen, P.; Looymans, M.; Van Velzen, J. (1996). "The application and system aspects of the Zeus display". Philips Journal of Research. 50 (3–4): 501. doi:10.1016/S0165-5817(97)84688-8.

van Eck, Wim (1 December 1985). "Electromagnetic radiation from video display units: An eavesdropping risk?". Computers & Security. 4 (4): 269–286. CiteSeerX doi:10.1016/0167-4048(85)90046-X.

Yuan, Wenyi; Li, Jinhui; Zhang, Qiwu; Saito, Fumio; Yang, Bo (1 January 2013). "Lead recovery from cathode ray tube funnel glass with mechanical activation". Journal of the Air & Waste Management Association. 63 (1): 2–10. doi:10.1080/10962247.2012.711796. PMID 23447859. S2CID 24723465.

Lu, Xingwen; Ning, Xun-an; Chen, Da; Chuang, Kui-Hao; Shih, Kaimin; Wang, Fei (1 June 2018). "Lead extraction from Cathode Ray Tube (CRT) funnel glass: Reaction mechanisms in thermal reduction with addition of carbon (C)". Waste Management. 76: 671–678. doi:10.1016/j.wasman.2018.04.010. PMID 29650298. S2CID 4800544.

Yin, Xiaofei; Tian, Xiangmiao; Wu, Yufeng; Zhang, Qijun; Wang, Wei; Li, Bin; Gong, Yu; Zuo, Tieyong (20 December 2018). "Recycling rare earth elements from waste cathode ray tube phosphors: Experimental study and mechanism analysis". Journal of Cleaner Production. 205: 58–66. doi:10.1016/j.jclepro.2018.09.055. S2CID 105023020.

Yu, Miao; Liu, Lili; Li, Jinhui (1 January 2016). "An overall Solution to Cathode-Ray Tube (CRT) Glass Recycling". Procedia Environmental Sciences. 31: 887–896. doi:

Herat, Sunil (2008). "Recycling of Cathode Ray Tubes (CRTs) in Electronic Waste". CLEAN – Soil, Air, Water. 36 (1): 19–24. doi:10.1002/clen.200700082. hdl:

Goldwasser, Samuel M. (28 February 2006). "TV and Monitor CRT (Picture Tube) Information". repairfaq.org. Archived from the original on 26 September 2006.

In 1897, German Physicist Karl Ferdinand Braun invented the earliest version of the cathode ray tube (CRT). Therefore, the CRT is also known as the Braun’s tube. Before digital and smart television become commonplace in modern society, most television used cathode ray tube (CRT), an electronic vacuum tube to display images or videos on the screen (University of Oxford Department of Physics 2018).

A cathode ray tube consists of several basic elements, which have been shown in the diagram. From the diagram we can see that the early CRT includes a vacuum sealed tube and on the tube there"s a cathode and an anode. Attracted by the anode, electrons will flow from the cathode towards the anode. And in the anode there is a small hole, which allows a small bit of electricity to pass through, generating a beam of electrons.

The two illustrations only show the simple form of CRT, for modern color television, the construction in the tube is much more complex in order to produce color images. Therefore, in color television there are three electron tubes in the CRT system and they are responsible for color red, green and blue separately to deliver color images on screen.

Though Japanese television manufacturers have mostly ditched tube TV manufacturing, their Chinese counterparts are just getting started exporting the sets.

Though more U.S. buyers have begun to snap up these high-definition flat panels, much of the rest of the world is still buying CRTs (cathode ray tubes), mostly because they"re more affordable in small to midrange sizes and there"s less demand for giant television sets in places other than the U.S. That"s good news for China.

Computer and TV screens with cathode ray tubes (CRTs) have not been sold in Europe since 2011, when, through technological advancements, they were replaced by new TFT (thin film transistor) and LCD (liquid crystal displays) screens. Considering the “service life”, i.e., the duration of the cathode ray tube screens, and the fact that they can still be found in households, it is clear that a considerable quantity of these devices is stored in landfills. Precise data on the amounts of generated waste CRT glass are not readily available. According to the data shared by the WEEE Forum, the amount of CRT displays generated in the Europe (30 countries) has been declining since 2009, and it is estimated that in 2020, this amount was around 250 kt [1]. In the USA, there are around 232 million CRT devices which are still being used, so considerable amounts of those devices end up in landfills each year—it is believed that around 85% of these devices will be collected in the next ten years. According to the data in Ref. [2], in the USA in 2018 alone, 500 kt of CRT waste was generated. In addition, Shaw Environmental Inc. (Hamilton Township, NJ, USA) estimated that around 3.2 million units of CRT technology would require proper waste management every year as it will reach its end of life in 2022 [2]. TV screens constitute the largest part of electronic waste in China, with around a 50% share. According to the research of Quinghua University, the total amount of collected waste CRT glass exceeds 5.2 million tons, with 3.5 million tons of tinted panel glass, 1.7 million tons of funnel glass and 0.7 million tons of black-and-white glass. However, due to the high cost of CRT glass recycling and low value of the obtained raw material, only a fraction of waste glass is recycled in China in a formal way, observing all the regulations protecting human health and the living environment [3]. According to Singh et al. [4], the estimated waste generation of CRT TVs in China in the period 2010–2020 is around 3240 kt. In Serbia, in 2016, around 3080 tons of CRT glass were collected. The current practice in Serbia is that the collected CRT glass is exported to other countries and the countries taking in the recycled CRT glass are paid for that [5]. The three basic glass elements of a CRT screen are neck glass, funnel glass and panel glass (Figure 1). Neck glass contains around 25% lead, which is far more than other parts. Funnel glass is the largest part of the cathode ray tube, and it contains around 20% lead. The panel is the visible front part of the cathode ray tube which contains almost no lead (0–3%). It is coated with barium and strontium layers whose role is to protect viewers from the adverse effects of UV and X-ray radiation. The funnel and panel are mutually joined by the frit.

At the start of the CRT glass recycling process, it is necessary to separate glass by types, because the different chemical composition of each type of glass in one cathode ray tube demands a different recycling method. It is standard to first breach the neck of the cathode ray tube to decompress the inside of the tube. Glass parts are separated in several ways: using hot band, diamond saw, jet or laser cutting [7]. Considering the problematic chemical composition of cathode ray tube glass (presence of lead), which constitutes the largest part of every screen, the transport and storage of such waste must meet special conditions. Therefore, from the environmental aspect, the recycling process of CRT glass is very important, but also complex—since there is no production of new CRT devices, there is no production process to which the old devices can be returned. The only option is to use the waste glass in new products. Over the past decade, extensive research was conducted on the possibilities of using waste glass in the production of crystal and radioactive glass, ceramic flags, artificial marble, glass jewelry, transparent lead coatings, sand–cement bricks, cement mortar and, to a smaller extent, concrete and concrete prefabricates.

The idea to use glass to make concrete is not new [8,9]. When making cement mortar, waste glass can be used as a filler, i.e., as a substitution for a certain amount of natural aggregate [10,11], most often as a replacement of a part of cement [12,13,14,15], or in road bases and sub-bases [16]. Researchers have investigated various types of waste glass: panel and funnel glass of CRT screens, decorative crystal glass, fluorescent lamp glass, glass food containers, facade glass, glass cullet, glass sludge (a side product of polishing and processing glass) and, in recent times, the glass from TFT–LCD screens. Hui Zhao et al. [17] tested the properties of mortar where a part of natural river aggregate was replaced by CRT funnel glass. The percentages of glass used to replace the fine river aggregate were 0%, 25%, 50% and 75% by mass. Mortars with added glass had a higher strength than the reference mortar at all ages. One research group explained this by the enhanced packing of the aggregate grains and with the assumption that the presence of CRT aggregate in mortar accelerates the cement hydration. Tensile bending strength was tested at the same mortar ages as the compressive strength. With the increase in the share of recycled glass in mortar, there was an increase in the strength of the mortar. The same authors proved that the inclusion of CRT glass sand in the concrete could also reduce the drying shrinkage of concrete and increase the alkali–silica reaction (ASR) expansion of the mortar. Gerry Lee et al. [18] determined that with the increase in the percentage of recycled glass replacing natural aggregate, irrespective of the fineness, there is a reduction in the density of concrete, which is explained by the lower specific gravity of glass in comparison to the fine natural aggregate. The research of Eshmaiel Ganjian et al. [19] included different recycled materials and the verification of their potential to be used in the production of concrete blocks. Materials used were granulated slag, dust from the cement production process, recycled gypsum panels, fly ash from chimneys and thermal power plants, metal dust from the iron alloying process and waste glass. Tensile splitting tests at the ages of 14 and 28 days determined that only the series with granulated slag and dust from the cement production process met the standard EN 1338 and durability requirements. Dondi et al. [20] tested the potential of the use of CRT glass for the production of bricks and roof flags. The experimental results indicate that both types of CRT glass have an impact on the reduction in the plasticity of unfired products and on the increase in shrinkage during drying. Andreola et al. [21] researched the potential of using CRT glass in the production of ceramic glazing. Glazing with CRT glass reduces the potential environmental hazard by 36% compared to ordinary glazing. Ceramic foam is most often used for thermal insulation and soundproofing as well as for absorption of harmful particles in the air. Ref. [22] indicated that one can successfully produce this foam with the addition of CRT glass. The use of conical glass for the production of crystals would reduce the addition of lead–oxide by 0.2 tons. Yu et al. [23] used cleaned funnel CRT glass for the production of fluorescent lamps with low lead content. Thung-Chai Ling et al. [24] researched the potential of using mortar with the addition of glass in radiology as an absorber of harmful X-rays. The best absorption of X-rays was observed in the mortar series in which the total amount of aggregate was replaced by CRT glass with a high content of lead. In the case of the sample 5 mm thick, 56.2% lower radiation was measured compared to a reference specimen of the same thickness. Such a result can be explained by the fact that CRT glass with lead has a higher density than natural aggregate and that its atomic structure acts on X-rays by reducing their energy and penetration depth.

Based on the review of a number of papers, it can be concluded that when CRT recycled glass is used to replace part of the natural aggregate in concrete, strength and tensile strength by bending are better, drying shrinkage can be reduced or increased (the results differ) and density is decreased. It is also concluded that few studies are based on concrete precast elements made with CRT glass. The subject of this paper is the production of concrete paving blocks and flags in which 50% of quartz in the finish–visible layer has been replaced by panel recycled cathode ray tube glass. The review of literature did not reveal any paper discussing this topic, which provides a certain originality to our paper. The main goal set for this research is proving the potential use of panel CRT recycled glass as a partial replacement for natural aggregate in the finish layer of concrete blocks and paving flags, which is a possible solution for disposal. We focus on the analysis of properties that relate the most to the finish layer of the paving elements. Within the experimental research, physical and mechanical properties as well as the durability of concrete are tested: shape and dimensions, splitting tensile strength, tensile strength by bending, water absorption, resistance to freeze/thaw and de-icing salts, wear resistance (Böhme test), slip resistance (SRT pendulum test), radioactivity and leaching. For the purpose of observing the concrete microstructure, SEM and EDS analyses were performed in order to acquire the knowledge of the concrete surface.

A television set or television receiver, more commonly called the television, TV, TV set, telly, tele, or tube,television broadcasts, or as a computer monitor. Introduced in the late 1920s in mechanical form, television sets became a popular consumer product after World War II in electronic form, using cathode ray tube (CRT) technology. The addition of color to broadcast television after 1953 further increased the popularity of television sets in the 1960s, and an outdoor antenna became a common feature of suburban homes. The ubiquitous television set became the display device for the first recorded media for consumer use in the 1970s, such as Betamax, VHS; these were later succeeded by DVD. It has been used as a display device since the first generation of home computers (e.g. Timex Sinclair 1000) and dedicated video game consoles (e.g. Atari) in the 1980s. By the early 2010s, flat-panel television incorporating liquid-crystal display (LCD) technology, especially LED-backlit LCD technology, largely replaced CRT and other display technologies.USB device. Starting in the late 2010s, most flat panel TVs began to offer 4K and 8K resolutions.