Electron Tubes

Industry Snapshot

Approximately 85 companies operated in this industry in 2007, down about 40 percent from the number of firms in the early years of the twenty-first century's first decade. After a period of growth during the late 1990s, the industry was affected by an economic recession, price erosion, and shifting consumer demands. Shipment values in 2008 were $1 billion while $345 million was spent on materials. The industry employed 5,241 in 2007 with 3,145 as production workers who earned $222 million in wages.

In the middle of the first decade of the 2000s, production of new and rebuilt receiving-type electron tubes, including cathode ray tubes (CRT), accounted for just under 75 percent of industry revenue. The other major product group, which accounted for approximately 20 percent of shipment values, consisted of transmittal, industrial, and special-purpose electron tubes (except X-ray tubes). The remainder of shipments consisted of electron tube parts.

Organization and Structure

The two most recognizable types of electron tubes were the ordinary television and computer tube and the once common vacuum tube traditionally used in radios and other electronic equipment. Generally speaking, electron tubes were sealed glass, enamel, or metallic tubes of varying sizes into which electrons were fired for the purpose of displaying images or conducting, transmitting, or multiplying light for non-display purposes. Although television tubes and computer displays were the most common products, industry firms also manufactured camera tubes, microwave tubes, Geiger counters, radar screens, and specialized devices such as electron beam (beta ray) generator tubes, klystron tubes, magnetron tubes, planar triode tubes, and tubes for operating above the X-ray spectrum.

Electron tubes varied according to the extent to which they were "evacuated," or emptied of gases and vapors; by the capability and type of the electron source; and by the number and configuration of electrodes they contained. The amount of power used in electron tubes ranged from milliwatts to hundreds of megawatts, and the frequency of operation ranged between zero and ten-to-the-eleventh-power Hertz depending on the type of tube. In general, CRTs operated by playing a beam of electrons of varying intensities over a display surface such as a phosphor screen, which formed patterns of light that took the form of characters or images. The three basic components of a CRT were the envelope, the electron gun, and the phosphor screen. The electrons were fired through a funnel-shaped element toward the faceplate on the broad end of the envelope that usually was made of glass. The electrons were heated and formed into a beam before being directed through the electron gun to different parts of the screen by the magnetic fields that surrounded the envelope. The phosphor screen consisted of a layer of phosphor dots that coated the inner surface of the CRT's faceplate. Color CRTs used a screen made up of red, green, and blue phosphors, with an electron gun for each color, while monochrome CRT screens employed one electron gun.

In the everyday family "direct view" TV, the face of the picture tube on which the electrons are projected is the same as the screen the viewer sees. In the rear-projection televisions that became increasingly common in the 1980s, images were projected indirectly from three small CRTS (one each for red, green, and blue) through a series of mirrors to a translucent screen. In the mid-1990s, projection TV tube manufacturers used compact CRTs and lenses with shorter focal lengths to reduce the amount of space taken up by the television box, reducing the size of the once bulky rear projection sets by one- third. In contrast to the 4:3 aspect ratio of the standard television tube, wide-screen TVs used a 16:9 ratio that resembled the wide ratio of movie theater screens and that allowed them to be marketed as the precursor to the so-called high-definition television (HDTV) technology trumpeted by Japanese TV makers in the 1990s. Computer CRTs increasingly took advantage of advanced data streaming technology to display downloaded and/or digital video disk (DVD) movies and multimedia entertainment.

Despite its continued popularity in the 1990s, the CRT was by no means a perfect piece of technology. The CRT remained the last holdover of the analog glass vacuum tube in a world increasingly permeated by digital solid state electronics technology. It was bulky, hot, and heavy, used large amounts of power, and was prone to disruptions of glare and magnetic and electrical fields. By the mid-1990s, few experts doubted the days of the CRT were numbered for mainstream computer and TV uses. High definition liquid crystal display (LCD) screens, which used an active matrix view panel, replaced them for computers. Display resolution often surpassed the capabilities of traditional CRT displays. While such technology was often far more expensive, the promise of continually decreasing manufacturing costs and higher consumer demand marked LCD technology as the heir-apparent to traditional CRT use for computer displays.

The second largest industry product group, transmittal, industrial, and special purpose electron tubes, included electro-optical tubes and miscellaneous special-purpose tubes. The electro-optical tube segment included everything from camera tubes and photo cells to other photo-conductive and photo-emissive tubes, most notably the airport bomb detector picture tube, the largest market of the electro-optical tube segment.

Microwave tubes were primarily used in high and ultra-high frequency applications such as radar, telecommunications equipment, military communication and control systems, high-frequency microwave ovens, scientific research equipment, FM radio transmitters, and industrial heating equipment. Traveling wave tubes, which were divided into forward and backward wave electron tubes, accounted for a majority of the microwave electron tubes produced. Microwave tubes comprised a majority of the power and special-purpose tube market. Gas tubes were used primarily in industrial applications because of their efficiency as well as their ability to handle high levels of power or current at generally low frequency levels. Product types included diodes, rectifiers, control-type industrial triodes, hydrogen and non-hydrogen thyratons, and other gas and vapor tubes. High-power tubes were also used in broadcasting transmitters. Vacuum tubes, once the primary element in electrical circuits, were mainly used in applications where low noise and high frequency were involved.

Background and Development

Electron tubes were the principal components of almost all electronic circuits and equipment until semiconductors were developed and began to replace them in the late 1940s and 1950s. The first application of CRT technology was for an oscilloscope in 1897, and the first television using a CRT was developed in the late 1920s. Commercial production of monochrome television picture tubes began in the late 1940s. After World War II, U.S. electron tube manufacturers found a diverse and lucrative market in defense applications, ranging from radar to communication and control equipment.

By the mid-1990s, the fastest-growing segment of the TV picture tube market was big-screen TVs that provided from 31 to 58 inches of viewable screen image. Despite the fact that by the mid-1990s nearly every U.S. home had at least one TV, there were 22.9 million direct-view TVs sold in 1999. In 1994 more than 26 million color TVs were sold in the United States. Spurred on by demand that was projected to reach $20 billion by the turn of the century, industry firms made significant strides in improving the CRT's resolution, brilliance, size, energy usage, and cost. Television tubes and computer monitors became flatter and bigger as the standard 14-inch PC monitor, for example, gave way to 17- and even 20-inch models; digital circuits were used to enhance picture quality; and advances in non-electron tube technology were developed so quickly that the CRT itself seemed destined for only niche uses in specialized applications.

In the 1990s the CRT sector of the electron tube industry continued to establish itself as the sector's primary revenue machine. Despite a drop in government spending for military-related CRT display technologies, the consumer computer CRT and television tube markets provided more than enough demand to fuel the industry's continued growth. Between 1994 and 1999, the value of PC system sales, which included a CRT monitor, grew almost 77 percent. Concurrent expansion occurred in the number of systems sold, which increased over the same period by 121 percent. A total of 90.5 million CRTs were sold in 1998, generating a $17.2 billion market share of the electron tube industry.

In the late 1990s, the battle between the computer CRT and the flat panel display (FPD) intensified. Developed in the United States, but later co-opted by Japanese firms, the FPD encompassed several display technologies, from active and passive matrix LCDs to field-emission, micromirror, diamond emission, and neon- or xenon-based gas plasma displays. By the late 1990s, FPD manufacturers had overcome hurdles in FPD design complexity and subsequent high cost and the technology's high power requirements. At one time, the only CRT markets immediately threatened by FPDs were point-of-sale terminals, medical imaging applications, and displays for instrumentation and factory automation. However, at the end of the twentieth century, manufacturers had broken out of the laptop and avionics display markets into the television tube and PC monitor markets that comprised the electron tube's home turf.

FPD technology began to be applied in a wide variety of ways at the end of the 1990s. According to the U.S. Display Consortium, innovative uses included analytical equipment, conference-room equipment, marine instruments, hand-held devices, electronic books, passenger entertainment systems, and home appliances. Cutting-edge technology also included filed emission displays (FEDs). According to Electronic Business, revenue from flat panel display sales at the end of 1999 were estimated at $11 billion.

Throughout the 1990s high-resolution HDTV was marketed as the next great advance in television technology. Because its superiority was only noticeable in 40-inch screens, the resulting increases in TV tube size spelled more trouble for the electron CRT's future. As the resolution of television screens increased, the brightness of the traditional CRT fell, and the FPD became no more expensive than a comparably sized CRT, but was 75 percent thinner. In addition, the distinction between the television tube and the computer monitor threatened to vanish as technologies like Zenith's "NetVision" allowed consumers to watch TV or surf the World Wide Web from the same screen.

Industry shipments declined from $3.82 billion in 1999 to $3.56 billion in 2000, while the cost of materials increased from $2.08 billion to $2.21 billion. Industry employment declined steadily through the late 1990s and 2000, falling from 21,656 in 1997 to 16,187 in 2000. The number of production workers over this period dropped from 16,774 to 12,718.

The electron tube industry continued to decline during the early years of the first decade of the 2000s in response to the economic recession, price erosion, and shifting consumer demands. Shipment values in 2002 were $2.45 billion, down 24 percent from 2001 and 36 percent from 1998. To limit losses, the industry reduced capital expenditures 75 percent during 2002, dropping from $162 million in 2001 to just $40.1 million in 2002.

Current Conditions

By the late 2000s, the future of CRTs was uncertain. The sales of CRT-based computer monitors were slipping. In 2003, U.S. sales of LCD models outpaced CRTs for the first time. Consumer demand, falling prices of LCD models, and computer packaging deals spurred the increased LCD sales. According to research firm ISuppli/Sanford Resources, the average selling price of a 17-inch LCD monitor fell from $915 in 2001 to $271 in 2005. On the other hand, a 17-inch CRT monitor that cost an average of $213 in 2001 sold for approximately $100 in 2005. Responding to consumer demand, computer suppliers like Dell offered aggressive packaging deals that included an LCD monitor.

In 2004 global shipments of LCD monitors overtook CRTs for the first time. According to the Japan Electronics and Information Technology Industries Association, sales of LCD monitors grew 36 percent during 2004, to 67.64 million units, while CRT monitor sales fell 11 percent to 59.64 million units. By the late years of the first decade of the 2000s, LCD monitors claimed as much as 75 percent of the market.

While LCD monitors are quickly outpacing CRT monitors, CRTs continue to hold their own in the television market and are expected to continue to do so until the price for flat-panel models falls below $500. In the early years of the first decade of the 2000s, CRT-based television sets accounted for nearly 98 percent of all sales, and in 2005 CRTs continued to hold approximately 85 percent of the market.

Despite the continued strong performance of CRTs in the television sector, the future seems to point toward flat-panels. In Popular Science, Mark Anders noted, "CRTs will probably be around for another decade, but even today the larger a TV is, the less likely it is to be powered by one. Tubes are just too big and heavy. . . . Of course, the CRT won't be completely supplanted until small-scale flat panels (under 19 inches) can compete on price." However, prices were coming down on flat-panels as sets that once cost $10,000 cost $2,500 by the mid-years of the first decade of the 2000s and dropped further in the decade's late years to where some could be purchased for less than $1,000.

Nonetheless, CRTs, which can be purchased in comparable size to flat panels for $300, continued to lead in the price wars in the early years of the first decade of the 2000s. In addition, CRT makers are not ready to concede the market to LCDs. Several manufacturers were working on new technology to decrease the size and weight of CRT models, and CRT flat-panel technology also is being advanced.

Industry Leaders

In the late years of the first decade of the 2000s, LG Display Co. (formerly LG Philips LCD Co.), based in Seoul, South Korea, was the world's leading manufacturer of CRTs. LG Phillips shipped $12.8 billion in products in 2008 to claim approximately one-third of the market share. Among the electron tube industry's leading firms during the late years of the first decade of the 2000s were Zenith Electronics Corporation, which had sales of approximately $109 million in 2008. The company was purchased by LG and shifted its focus to research and development. Other major industry players included Hitachi Electronic Devices; Toshiba Westinghouse Electronic; GM Hughes Electronics Corporation; Hewlett-Packard Co.; ITT Corporation; Litton Industries Inc., Electron Devices Division; Philips Electronics North America; and Raytheon Electronic Components.

Research and Technology

The growing demand for computer monitors for use in homes and offices starting in the 1980s forced industry firms to develop more user-friendly monitor designs, such as the "flatsquare CRT," in which the curvature of the CRT's screen was greatly reduced. CRT display technology also continued to evolve in the areas of unit price and color display capabilities.

The application of multifunctional CRT displays in the instrument panels of military aircraft, and, to a lesser degree, commercial aircraft, continued in the 2000s. However, the inherent disadvantages of CRTs, including limited screen size, unwieldy shape, high power requirements, and fragility, led manufacturers to investigate alternatives to CRT technology, such as light-emitting diodes, FPDs, and LCDs. Improvements in LCDs, which were thinner and lighter than CRTs, enabled them to compete in price with CRT-based, large screen, video data projectors while offering roughly two to four times their brightness.

Flat panel displays increasingly emerged as the favored display technology, especially in aircraft cockpit applications where limited space and high levels of glare diminished the usefulness of CRTs. Field emission display, another emergent technology that further threatened to unseat the electron CRT, was structurally less complex and thinner in size than LCDs. Field emission displays were based on vacuum microelectronics and combined the advantages of vacuum tube technology with the benefits of digital computer chips. Advances in research and technology also continued in non-CRT product categories in the first decade of the 2000s. Direct broadcast satellites that used electron tubes, such as traveling wave tubes, for non-cable HDTV transmissions, as well as for other uses, were developed for satellite tubes and uplink stations with tube lifetimes of up to 15 years.

To combat the onslaught of the flat-panel television industry, some CRT manufacturers were pushing new technology to make CRTs flatter and lighter than their predecessors. A 36-inch CRT television can weigh as much as 200 pounds and is 20 to 24 inches deep. In 2005, LG Phillips Displays and Samsung used new CRT technology to introduce CRT models that were much smaller than their predecessors. Although the models, which were 14 inches deep, were still much bigger than their LCD counterparts, the manufacturers argued that most DVD players are 12 to 14 inches deep, so the consumer already allotted that much space. Pure flat screen CRT technology also was being advanced. The prototypes of the new flat CRT technology cost about 30 percent more than a traditional CRT model but were still 50 percent less expensive than a comparable LCD set.