Cold cathodes are heating up

Reviewed by: The TVs of Tomorrow: How RCA's Flat-screen Dreams Led to the First LCDs by Benjamin Gross Michael Aaron Dennis (bio) The TVs of Tomorrow: How RCA's Flat-screen Dreams Led to the First LCDs By Benjamin Gross. Chicago: University of Chicago Press, 2019. Pp. 288. We live surrounded by LCD (liquid crystal display) screens; Ben Gross's volume explains the origins of this technology at RCA and how the iconic American firm failed to deliver it to the world. This fascinating story of industrial research, corporate politics, and technological change blends science, technology, and business histories. Gross locates the emergence, efflorescence, and decline of LCD screens at the intersection of three distinct axes—the material logic of LCDs, that is their physical chemistry and often recalcitrant behavior plus the infrastructure for their creation and use; RCA's strategic goals as well as the Sarnoff Laboratory's role in fulfilling them; and the interactions among researchers, their managers, and other RCA divisions. One of the many interesting things readers learn is that the technology dominating our lives received so little support from RCA management. Indeed, they ultimately seemed to value LCD patents more than developing televisions based on this novel display technology. Noteworthy are Gross's discussions about the problem of finding the sources needed to write the history of late twentieth-century corporate R&D. RCA's quest for a follow-up to its color television came in 1951, with legendary founder David Sarnoff's challenge to develop a light amplifier. Efforts ensued to find alternatives to the standard display technology, the CRT (cathode ray tube). RCA pioneered the mass production of these glass bubbles, and it proved hard to break from this anchoring technology. Only after it became clear that CRTs could not be flattened in order to hang from walls and display a quality picture did researchers and management explore and develop alternatives. By 1964, the company's research included liquid crystals and their chemistry; however, as Gross points out, it was never really a large research group. Compared to the well-studied RCA video disc, called a "Manhattan Project," RCA's work on LCDs was a modest effort. Although [End Page 1240] public relations people hyped the research and its potential, this was never a corporate moon shot. Gross rightly highlights the problems in manufacturing the new technology once researchers overcame problems at the bench. Using laboratory notebooks, he delineates how researchers solved the issue of LCDs working at room temperature. Building bridges with RCA's manufacturing divisions became as vital as laboratory research to keep LCD work alive, while management paid more attention to a struggling computer effort and the firm's traditional color television business. Even once the multiple manufacturing problems were solved, the LCDs produced by RCA were for watch displays, not the wall-hanging televisions of the future. The initial secrecy surrounding LCD research demonstrated how highly it was valued, yet RCA soon viewed patents as the real source of value compared to physical products, given the costs and difficulties of profitably manufacturing LCDs in America. Gross's interviews and archival work display the full range of skills required to move lab products to the factory, including individuals with the requisite social skills to borrow resources from other groups. This social aspect of intra-laboratory relations is especially well portrayed. Gross plays with Clayton Christensen's ideas of disruptive innovation in explaining why RCA failed to capitalize on its role as a pioneer in LCD research. He follows LCD researchers at RCA to a new start-up, Optel that fails to take advantage of new LCD chemistry, instead sticking to RCA-based technologies. Small size did not prevent an aversion to change. In his final eloquent chapter, Gross explains that it was only once LCD technology had left RCA that it really grew and developed—as multiple firms, first on the West Coast and then in Japan, invested in significant R&D with specific products in mind. Seiko developed a watch-sized LCD television more advanced than Dick Tracy's, while Sharp demonstrated a fourteen-inch color display in 1988. Ironically, Sharp had approached RCA in 1970 about...

In the past, the ubiquity of the cathode ray tube (CRT) display meant that it was reasonably easy to visually evaluate the color of images for public broadcast or viewing. With the advent of the latest display technologies, consumers are viewing an array of display types other than CRT, including liquid crystal display (both cold-cathode fluorescent lamp and light-emitting diode backlit), plasma, and recently organic light-emitting diode. Although high-definition television has gone a long way toward unifying broadcast standards worldwide under the BT.709-5 standard from the International Telecommunications Union Recommendations Section, studios are clinging to their remaining CRT broadcast monitors as references for how their images look to the average consumer. Is this still a valid way to work? Should we be sticking to CRT devices as our reference, is it time for a new reference, or is the whole concept of a color reference display no longer valid?

Parasitic capacitors, which occur between cold cathode fluorescent lamps (CCFLs) and the back-plank in backlight modules of liquid crystal display (LCD) panels, are changed by the lamp position. That's the reason why the leakage currents are different from lamps; therefore, the undesirable non-uniform brightness exists. This paper presents a novel structure of backlight module for LCDs, aiming at alleviating the influence of parasitic capacitors in order to attain balanced lamp currents and uniform brightness outputs. By designing a new back-plank, the spaces between the lamps and the back-plank are approximately identical, as a new structure implemented on a direct-type backlight module with 14 CCFL lamps for a 32-inch LCD panel, then experimental results demonstrate that the difference of parasitic capacitors can be reduced to be within 2 %.

To compare the observer performance 0f liquid crystal display (LCO) and cathode ray tube (CRT) monitors in detecting experimentally induced pulmonary edema in pigs by using soft-copy images of amorphous selenium-based flat-panel-detector radiography (OR) and storage phosphor computed radiography (CR). Oleic acid was injected intra-atrially into three pigs (weight, 20-25kg) at doses of 0.04, 0.05, and 0.06 ml/kg to induce pulmonary edema. Each set of CR, DR, and thin-section CT scans were obtained every 20-30 minutes from three pigs over 4-6hours. Thus, 37 sets (10 sets from pig-1, 11 sets from pig-2, and 16 sets from pig-3) of radiographs were obtained. Images were masked for identity. randomly sorted, and displayed on both live mega pixel (2048 x 2560 x 8 bits) LCD and CRT monitors. Eight radiologists rated each image for Ihe presence of ill-defined diffuse opacities and reticular-Iinear opacities in both lungs by using continuous rating scale of 0-100. A total of 4736 (37 sets 2 detector system 2 fields 2 lesion types 8 observers 2 monitor systems) observations were analyzed in terms of receiver operating characteristics. Average observer performance in detecting ill defined diffuse opacities, LCO and CRT monitors were not different significantly in both OR and CR images. Average performance in detecting reticular-linear opacities was significantly better with LCD than CRT. These differences were significant in evaluating DR images (AUC=.852±.038 on LCD; AUC=.785±.070 on CRT) but not significant in evaluating CR images (AUC=.795±.060 on LCD; AUC=.745±.070 on CRT) System on both LCO and CRT monitors (p=.042 on LCD; p=.044 on CRT). Moreover. with OR system. observer performance was better with LCD monitor than with CRT monitor (p=.013), whereas with CR system, observer performance was not different significantly on both monitors (p=.11 8). Overall the five-megapixel LCD monitor was equal or superior to CRT monitor of the same pixel size in detecting experimentally induced pulmonary edema. Moreover, the LCD monitor appears, to be more optimized for detecting pulmonary reticular-linear opacity, when interfaced with DR system rather than with CR system.

Liquid crystal display (LCD) monitors are nowadays standard in computerized visual presentation. However, when millisecond precise presentation is concerned, they have often yielded imprecise and unreliable presentation times, with substantial variation across specific models, making it difficult to know whether they can be used for precise vision experiments or not. The present paper intends to act as hands-on guide to set up an experiment requiring millisecond precise visual presentation with LCD monitors. It summarizes important characteristics relating to precise visual stimulus presentation, enabling researchers to transfer parameters reported for cathode ray tube (CRT) monitors to LCD monitors. More importantly, we provide empirical evidence from a preregistered study showing the suitability of LCD monitors for millisecond precise timing research. Using sequential testing, we conducted a masked number priming experiment using CRT and LCD monitors. Both monitor types yielded comparable results as indicated by Bayes factor favoring the null hypothesis of no difference between display types. More specifically, we found masked number priming under conditions of zero awareness with both types of monitor. Thus, the present study highlights the importance of hardware settings for empirical psychological research; inadequate settings might lead to more “noise” in results thereby concealing potentially existing effects.

As time gets advanced multiple progressions have happened in the field of display devices. In this field first came a small LED then after CRT (Cathode Ray Tube) which is used in present days but due to its heaviness, we do not carry it from one place to another. Then after came LCD (Liquid Crystal Display), the problem of bulkiness and required large area overcome by LCD, the only problem with LCD is that it cannot see a clear picture from different angles. LCD is a lightweight and flexible plastic substrate. After all these innovations OLED came and OLED beat all issues of LCD and CRT. OLED is light and slim in design, it does not require any kind of backlight, OLEDs are self-luminous. Polymers are using to fabricate OLEDs or unlike LCDs small molecules in the flat panel zone. It has low power consumption (only 2-10 volts) also OLEDs has a wide viewing angle (up to 160 degrees). The applications of OLEDs in electronics are on the increase on daily basis from camera to cell phones to OLED televisions.

To compare the modified signal-to-noise ratio (SNR*) of multifocal visual evoked potential (mfVEP) responses elicited by a cathode ray tube (CRT) and liquid crystal display (LCD) monitor in normal subjects. An LCD monitor and CRT monitor were luminance and contrast matched. Luminance stability and the effect of viewing angle on luminance and contrast was measured for both screens. The SNR* of mfVEP responses from 15 normal subjects was compared between the stimulators using repeated measures analysis of variance. The CRT monitor took 10 min from switch on to reach the desired luminance compared to 60 min for the LCD monitor. LCD luminance was sensitive to variations in ambient temperature, fluctuating by 10 cd/m(-2) over approximately 20-27 °C, whereas CRT luminance was stable. Luminance variation from the centre to the edge of the CRT screen was 8 % when viewed perpendicularly and 28 % when viewed at an angle of 25°, compared to 24 and 46 %, respectively, for the LCD screen. Contrast was >94 % and varied by <3 % across both monitors for both viewing conditions. There was no significant difference in SNR* between responses elicited by the two stimulators (p = 0.76). CRT and LCD stimulators elicited mfVEP responses with similar SNR* in normal subjects. This study highlighted practical issues with the use of LCD monitors as visual stimulators, particularly with regard to warm-up time, luminance stability and luminance uniformity.

The fine-tube cold cathode fluorescent lamp (CCFL) [1-2] and external electrode fluorescent lamp (EEFL) [3-9], have been widely used as a backlight source in liquid crystal display (LCD) modules. In a notebook PC, the glass tube diameter of the lamp is a small as 1 mm. As the display area becomes larger in LCD TVs, the tube diameter is 3~4 mm and the lamp length is up to 1~2 m. However, the mechanism for radiation of light along such a long positive column is not well understood. The characteristics of light emission in the EEFLs have been reported, specifically the propagation of a light-emitting along a tube driven by high voltage AC [8-9]. In the long positive column lamp, the light emits first from the side of high voltage propagates to the ground side with the propagation time of ~┤s and the propagation velocity of 105~106 m/s. The previous observations have not been reported elsewhere to our knowledge since the fluorescent lamps have been introduced commercially in the 1940's. However, those observations of light propagation would not be recognized even if they have been found first in the history of fluorescent lamps. Even more, those observations are misapprehended as the kinds of unstable waves during the lamp operation of lamp, such as striation, snaking, flickering, and streaming, etc. Generally, a moving light source in the long positive column plasma has been associated with “striation”. A striation is a quasistanding wave which can be observed visually [1012]. However, striations as well as the other unstable waves are not observed in commercial lamps, and would be considered a major defect for hot cathode fluorescent tubes as well as CCFL. In the manufacture of those lamps, inadequate vacuum during the evacuation process results in impurity gases such as H2O, CO2, O2, and N2, etc. These impurities cause the perturbations of unstable discharge, and those lamps are discarded in the production line. Striations can sometimes appear in aging lamps or in the operation with an unstable inverter system. However, we have never observed striations in the normally manufactured lamps of our test samples. Our observation of optical signal is quite different from striations, as it is not visible to the naked eye and moves on the micro-second timescale. Rather than the instability, they are related to the stable process of distribution of plasma and fields that generate light in these discharges.

Although there are remarkable differences in maximum luminance in cathode ray tube (CRT) and liquid crystal display (LCD) monitors and film/viewer systems, these differences cannot be recognized in our perception of them. To clarify the reason for this conflict, we analyzed the psychophysical gradient (delta), which is based on the minimum perceptible luminance difference (DeltaL(min)) and can express contrast visually recognized by observers. In this study, we first confirmed the compatibility of the psychophysical analysis to the CRT and the LCD monitors by using their threshold contrasts (C(t)s). Second, we calculated and compared the delta's of the above output devices. The C(t)s values of each device were in good agreement. Moreover, the Moon & Spencer model, which expressed the perceptibility of luminance change, was well suited to the measured C(t)s over the whole luminance range. The psychophysical analysis is therefore available not only for the film/viewer system, but also for the CRT and LCD systems. The difference of physical gradient G of the luminance characteristics curve among the output devices was larger than 20 times, whereas that of d was within 3 times. The display devices listed in the order of decreasing delta were film/viewer>LCD>CRT. These results corresponded to the visual contrast sensation and our clinical experience, which cannot recognize remarkable differences in perception. By using the psychophysical analysis, we clarified the reason for the conflict between the results of physical evaluation and the contrast visually recognized by observers.

Electrical and electronic waste (E-waste) has become a great matter of concern all around the world. Due to the fast growth in kinescope technology, Cathode Ray Tubes (CRTs) are being replaced by lighter and thinner panels with flat displays, namely – Light Emitting Diodes (LEDs), Plasma Display Panels (PDPs) and Liquid Crystal Displays (LCDs). The environmental hazards caused by CRTs waste generation have become an extensive dilemma around the globe. Lead is contained in sufficient amounts in the waste CRTs, which causes serious hazards to human health and the environment. The increasing demand for concrete and natural resources due to swift urbanization has made it crucial to replace the natural aggregates in concrete either as a partial replacement or total replacement, without affecting the concrete performance. CRT waste glasses are abundant in silica, have low water absorption property and adequate intrinsic strength. These characteristics of CRT waste glass make it apt for usage as pozzolan or sand in construction materials. They can be partially or totally replaced for natural sand as fine aggregate in concrete. This review work extends an in-depth summary of literature detailing the reuse of CRT glass waste as a fine aggregate replacement in concrete. The properties such as water performance, thermal property, strength and durability of CRT glass waste-based concrete and their method of manufacturing have also been studied in this paper. Furthermore, a comparative performance analysis of CRT glass waste concrete with other E-waste incorporated concrete has also been included in this paper. The current work shall contribute to enhancement towards sustainability and economic development of CRT glass waste incorporated concrete in the construction industry. Thus, the issues related to CRT glass waste such as contamination of soil, environment and water bodies, health issues caused to living beings and simultaneously, the degradation of natural restricted aggregate resources could be reduced considerably by several folds.

11 - Tripping the Light Fantastic

Liquid-crystal-displays (LCDs) and cathode-ray-tubes (CRTs) are compared with regard to color-calibration and color gamut. Applicability of common display calibration models to LCDs and CRTs is experimentally tested. Color-calibration accuracy, ease of calibration, and achievable color gamut are evaluated for the displays. An offset, matrix, and tone-response correction model is found to be suitable for color calibration of LCDs for most applications. The model, however, results in larger calibration error for LCDs than for CRTs, and unlike CRTs a power law tone-response correction is unsuitable for LCDs. A very significant color variation is seen with change in viewing angle for the prototype LCD display employed in the study. The LCD display provides a significantly larger color gamut under typical viewing conditions than CRTs, primarily due to higher luminance.

Achieving precise display timing in visual neuroscience experiments

Chapter 5 - Performance Characteristics

We developed two mobile-device size autostereoscopic integral videography (IV) displays with field sequential color (FSC) liquid crystal displays (LCDs) and micro lens arrays. IV is an autostereoscopic video technique based on integral photography. The FSC-LCD has a different backlight from that of conventional LCDs. The backlight is produced by red, blue, and green light emitting diodes (LED) instead of by cold cathode fluorescent lamps, and each LED emits light sequentially. IV based on FSC-LCD doesn't cause color moires because the FSC-LCD does not require color filters. One FSC-LCD IV display is 5-inch diagonal with 256×192 lenses and 20 ray directions. Its base FSC-LCD is 300ppi with 1280×768 pixels. The other FSC-LCD IV display is 4.5-inch diagonal with 192×150 lenses and 80 ray directions. Its base FSC-LCD is 498ppi with 1920×1200 pixels. In this paper, we first describe the problems of a previous conventional LCD-based IV displays, and then describe the principle of the IV displays based on the FSC-LCDs. Next, we analyze the IV displays by a plenoptic sampling theory. Lastly, we compare three versions of the IV displays, two based on the FSC-LCDs and one based on the conventional LCD.