difference between tft lcd and crt quotation

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difference between tft lcd and crt quotation

No native resolution. Currently, the only display technology capable of multi-syncing (displaying different resolutions and refresh rates without the need for scaling).Display lag is extremely low due to its nature, which does not have the ability to store image data before output, unlike LCDs, plasma displays and OLED displays.

difference between tft lcd and crt quotation

The obsolescence of CRT monitors requires replacing stimulators used for eliciting VEPs with new monitors. Currently, LCD monitors are the only suitable alternative, however other technologies, like OLED, may become a viable option [23]. So far, the ISCEV extended protocol for VEP methods of estimation of visual acuity recommends ensuring luminance artifacts caused by non-CRT stimulators [9], which can be achieved by reducing the stimulus contrast [23]. However, this may not be possible without falling below the minimum contrast values recommended for VEP [1, 23]. Since LCD stimulators have been shown to result in mostly a delay in the VEP responses [2,3,4, 23] but seem not to affect the size of the amplitudes [2], we expected no difference between the estimated visual acuity by using LCD or CRT monitors used as a stimulator for the sweep VEP.

The results of the first experiment show statistically significant effects of the monitor type on the time-to-peak after stimulus onset and the peak-to-trough amplitude (Table 1). The mean delay of the time-to-peak after stimulus onset between recordings obtained using the LCD and the CRT monitor was about 60 ms, which is quite high and possibly caused by the relatively old LCD monitor used. Accordingly, statistically significant effects on the time-to-peak after stimulus onset and the peak-to-trough amplitude were found for the monitor/contrast combination in the results of the second experiment (Table 4). Surprisingly, the mean delay of the time-to-peak after stimulus onset of the CRT monitors with high contrast was with up to 151 ms, longer (Table 5) than that of the LCD monitors (with low and high contrast), although one would expect modern monitors to have shorter or even no delays [24, 25]. Additionally, a statistically significant interaction between the spatial frequency and the monitor type was revealed in both experiments, causing an increased time delay for the intermediate spatial frequencies (1.4–10.3 cpd) with LCD stimulation (Fig. 2, top left) in the first experiment and an almost linear increase with the spatial frequencies in the second experiment (Fig. 2, bottom left). This may be explained by the semi-manual cursor placement, which is necessary because the amplitudes are less pronounced at frequencies below and above this frequency band. Another cause might be an input lag resulting from the time required by the monitor to prepare the image data to be displayed. This could be caused by, e.g., internal scaling for non-native resolutions, which may even be present when using the monitor’s native resolution. In the worst case, this leads to nonlinearities of the response timing of the LCD monitor when presenting patterns of low or high frequency [26, 27]. In doubt, the precise duration of the input lag should be measured using a photodiode attached to the display [28] and in case of being constant, the delay could then be subtracted from the respective time-to-peak values. Finally, the higher latencies may also be caused by the different software used for generating the stimuli: whereas in the first experiment, a custom-developed Java-based software was used, in the second experiment, the Python-based PsychoPy was employed. Nevertheless, these differences seem not to affect the estimated visual acuity. The mean peak-to-trough amplitude using the LCD monitor in the first experiment is reduced by about 0.9 µV with a confidence interval from − 1.6 to − 0.2 µV compared to the CRT stimulator, but increased by about 2.6 µV (confidence interval from 1.2 to 4.0 µV) when comparing the new LCD monitor with the CRT monitor (both with high contrast) in the second experiment (Table 5). However, these differences were, despite being statistically significant, within the expected standard deviation from about 0.5 to 7 µV of the P100 amplitude found in the literature [29,30,31] and therefore probably of no clinical relevance (Fig. 2, right). Interestingly, the results of Nagy et al. [2] suggest a similar reduction in the peak-to-trough amplitude when using an LC display for stimulation. In the first experiment, no statistically significant interaction between monitor type and spatial frequency on peak-to-trough amplitude was found but a tendency to smaller amplitudes at intermediate frequencies (Table 1), whereas in the second experiment, the effect of the interaction of stimulator and spatial frequency was statistically significant (Table 4). It has to be taken into account that the residuals of the models were heteroscedastic and therefore the statistical significance of the effects may be overestimated [32].

In the first experiment, the difference between the subjective visual acuity and that estimated by the second-order polynomial method, or by the modified Ricker function, was not statistically significant from a hypothetical assumed value of 0 logMAR (Table 2). Neither were the variances between CRT and LCD statistically different. Accordingly, the linear mixed-effects models revealed no statistically significant effects of neither the monitor type, the recording cycle, nor their interaction on the difference between subjective and estimated visual acuity for both estimation methods (Table 3).

In contrast in the second experiment, the differences between subjective visual acuity determined using FrACT and the visual acuities estimated using the modified Ricker function along with the conversion formula used in the first experiment were significantly different from the hypothesized difference of 0 logMAR for both, the new gaming LCD monitor and the old LCD monitor, at high and low contrast, but not for the CRT monitor. After using an individually adjusted conversion formula for each monitor/contrast combination, no statistically significant difference from the hypothesized difference of 0 logMAR was found (Table 7). However, one should keep in mind that using the results to calculate the conversion formula used to predict the results is circular reasoning. Nevertheless, it indicates, that using individual established conversion formulas calculated from a sufficiently large number of normative data will minimize the error between true visual acuity and estimated visual acuity.

Table 6 lists the signal-to-noise ratio calculated from the fitted Ricker model for the different combinations of monitors and contrasts. The highest SNR was found for the CRT monitor using high contrast. The LCDs showed lower SNR values. The on average higher amplitudes obtained using LCD monitors (Table 5) indicate that more noise is present when stimulating using LCDs. However, this effect could be caused by the different software used for the stimulus presentation and the lower number of sweeps recorded for averaging compared to the recordings using the CRT monitor. Nevertheless, none of the differences between the SNR values obtained from the different monitor types was statistically significant (Table 6), which corresponds to the findings of Fox et al. [28].

We want to point out the limitations of the current study: We included only healthy participants, so the possible effects of LCD stimulators on patients with reduced visual acuity remain unclear and should be further investigated, especially since we found a statistically significant, albeit not clinically relevant, effect of the monitor/contrast combination on peak-to-trough amplitude and time-to-peak after stimulus onset in the second experiment (Tables 4, 5). Further limitations are that the participants were not stratified by age and that the subjective visual acuity in the first experiment was determined using an eye chart projector, in contrast to the second experiment, where FrACT was used, limiting the accuracy of the estimated value. Finally, this study compared only three specific monitors; therefore, the results are not universally valid.

In conclusion, based on the results of this study, LCD monitors may substitute CRT monitors for presenting the stimuli for the sweep VEP to objectively estimate visual acuity. Newer LCD screens, especially with low response times in the range of 1–2 ms, therefore, allow for a reduction in luminance artifacts at required contrast levels [23], albeit the luminance artifact may not have a large effect on the recorded signals [28]. New technologies like OLED displays [23] may even be better suited, since one the one hand, the onset will be the same for the whole pattern, and on the other hand, LCDs and OLEDs provide a constant luminance level during stimulation, whereas CRTs need a constants pulses to keep the phosphor lit up, causing fast local luminance flashes all the time [28]. Therefore, in contrast to CRTs, LCD and OLED stimulators, e.g., may allow for recording true offset responses [33]. However, caution should be taken when leveraging modern displays for stimulation, since their in-built electronics perform all kinds of sophisticated image-enhancing procedures including color-correction, brightness boosting, contrast enhancement by real-time adjustments of the colors or the backlight, or eyestrain-reducing blue light filtering, with the aim to improve the users’ experience, or to increase the monitors lifetime. This applies in particular to consumer electronics like TVs. Gaming monitors, in addition, use special acceleration drivers, which shut down the backlight, insert black frames (Black Frame Insertion, BFI), or employ variable refresh rates (e.g., Nvidia G-SYNC or AMD FreeSync) to clean the retained image from the eye. Therefore, one should disable any image processing or enhancing functionality in the monitor settings, before using the monitor as stimulator for electrophysiological experiments. Finally, it is advisable to perform a calibration with healthy volunteers using best-corrected and artificially reduced visual acuity and to collect normative data for the employed setup, as always recommended by ISCEV [34], in order to establish an individual conversion formula between the sweep VEP outcome and the estimated visual acuity.

difference between tft lcd and crt quotation

What are the differences between CRT and LCD? CRT and LCD are both monitors we know well, but what are the differences between them? Let"s find out together:

2.LCD: The structure of LCD is to place a liquid crystal cell between two parallel glass substrates, a TFT (thin film transistor) is arranged on the lower substrate glass, and a color filter is arranged on the upper substrate glass.

1. CRT display: CRT displays display images by exciting phosphors on the inner surface of the screen by electron beams. Since the phosphors are lit and then quickly extinguished, the electron gun must continually cycle to excite the dots.

2.LCD: By changing the signal and voltage on the TFT to control the rotation direction of the liquid crystal molecules, so as to control the polarized light emission of each pixel or not, to achieve the purpose of display.

What are the differences between CRT and LCD? The above are the differences between CRT and LCD. And LCD is gradually replacing CRT as the mainstream trend of the market.

difference between tft lcd and crt quotation

First, we will provide a brief technical overview of functional principles as they relate to visual stimulus presentation. Detailed descriptions and parameter measurements are already available from the existing literature; however, our intention here is to equip readers with limited technical expertise with the necessary knowledge to set up computer experiments with LCD monitors. Thus, we keep our explanations relatively short and simplified.

LCD monitors work differently: Each pixel consists of liquid crystal threads that can be twisted or arranged in parallel by an electrical current applied to them. This leads to a polarization effect that either allows or prevents light passing through. A white light source located behind this crystal array uniformly and constantly illuminates the array. To display a black pixel, the crystal threads are twisted by 90° such that no light will pass through. A white pixel is achieved by aligning the crystals such that maximum light is allowed to pass through, until a different, non-white color needs to be displayed (see the lower panel of Fig. 1 for an LCD pixel’s brightness over time). This is a static process, not a pulsed one as in CRTs.

In theory, the difference in presentation methods, namely a strobing versus a static image, should be of no consequence if the light energy that falls onto the retina remains the same over the time period of one single frame. As the Talbot-Plateau law states2 is equally well detectable as a light flash presented for 60 ms at 40 cd/m2. This suggests that temporal integration can be easily described by energy summation”. Thus, in principle, LCD and CRT monitors should be able to yield comparable results.

However, due to the differences in technology, the visual signals produced by the two display types have different shapes (i.e., a different light energy-over-time-curve; see Fig. 1). Moreover, default luminance as well as visual-signal response times (in addition to other parameters, see below) differ between most CRT and LCD monitors

Table 1 reports the parameters we considered in setting up the CRT and LCD monitors. Certainly, most of them are commonly considered when setting up a computer experiment; nevertheless we deemed it important to mention them here explicitly, as their neglect might have unintended consequences. We used a 17” Fujitsu Siemens Scenicview P796-2 CRT color monitor previously used in several published studies including studies with masked presentation conditions

We tested various monitor user settings, refresh rates, resolutions and luminance settings (see materials available at https://osf.io/g842s/) with regard to the emitted light energy–over-time-curve and therefore response characteristics (i.e., onset and offset of full screen and centrally presented stimuli). Measurements were conducted with a photodiode setup, using both an oscilloscope (model “Agilent MSOX 3012 A”) and a self-developed microcontroller setup as measurement devices. Stimuli were black and white squares.

Our measurements revealed several interesting characteristics: First, luminance of the LCD monitor at default setting (i.e., maximum brightness) exceeded the CRT luminance at a ratio of 3.25:1. However, comparable average luminance can be (and was) achieved by downregulating the LCD monitor (the older CRT technology emits less energy even at maximum settings, see Table 2), without participants perceiving it as unnaturally dark. If one plans to upgrade from CRT to LCD monitors in an experimental laboratory, we therefore recommend measuring the CRT monitors’ brightness levels and matching them in the new LCD monitors’ user setup, if comparability with the old setup is needed. This will minimize hardware-dependent variability, thus contributing to better replicability. Please note that a brightness adaption is not a necessary precondition when employing LCD monitors; researchers should simply be aware that the brightness level can have an influence onto the resulting effects, especially in time-critical experiments with short and/or masked presentation. Thus, we recommend the adaptation for time-critical experiments in which researchers orient on existing empirical evidence gathered with CRT monitors. Furthermore, gray-to-gray response times varied slightly depending on the employed brightness levels2), so we suggest that researchers can rely on this more efficient method as an approximation.

For the empirical comparison of human performance with CRT and LCD monitors, we relied on these results and set the monitor settings accordingly (see Method section below).

Participants were administered a masked number priming task and a subsequent forced-choice prime discrimination task using both a CRT and an LCD monitor. In this well-established paradigm

difference between tft lcd and crt quotation

The recent surge in thin-film transistor (TFT) technology, specifically for the TFT LCD display, is making CRT (cathode ray tube) monitors a thing of the past. In fact, TFT display is being used in almost all LCD monitors these days, most notably in computers and televisions.

It owes its popularity to its ability to refresh the screen quicker than a CRT, thanks to the fact that its small transistors require such a tiny charge to engage. Aside from this, TFT displays boast other advantages that give ample reason for manufacturers and businesses to widely use it in their digital products.

Because TFT displays are handy, these can easily be transferred, moved around, and installed. It can also be mounted, freeing up space that can be used for other equipment or tasks. This makes TFT monitors a perfect choice for creating a functional workstation. With this technology, businesses can maximize the use of their workspace by keeping unwieldy monitors out of the way.

If you’re worried about ballooning energy bills, a TFT monitor can help lower them. Since it uses pixels to display images, it uses less energy than CRT monitors. In fact, you can save up to 78% in energy use when you use a TFT monitor.

Say goodbye to blur with a TFT module. It uses a flat matrix display in which all pixels remain active, thus eliminating flickers. There are also no geometric distortions to worry about, unlike a CRT screen that tends to obscure images because it electronically focuses on the image from the inside while displaying it from the rear.

Because it’s flicker-free, you can ensure a sharp visual from a TFT-module monitor, which helps avoid physical symptoms of overexposure to computers or televisions. It does not create strain on the eyes, nausea, or headaches.

Thin-film transistor (TFT) modules are ideal for graphic artists, web designers, photographers, and other media types who require two monitors simultaneously to do their work. Moreover, TFT modules enable dual monitor configurations. All your computer needs is a video card or a couple of monitor connections.

Because of these advantages, the TFT LCD display has gained prominence among many industries. Understanding how it works and how it can help promote your business will help you engage it based on your specific needs.

difference between tft lcd and crt quotation

The liquid crystal display (LCD) technology has been used in several electronic products over the years. There are more reasons for LCDs to be more endearing than CRTs.

difference between tft lcd and crt quotation

CRT stands for Cathode Ray Tube and LCD stands for Liquid Crystal Display area unit the kinds of display devices wherever CRT is employed as standard display devices whereas LCD is more modern technology. These area unit primarily differentiated supported the fabric they’re made from and dealing mechanism, however, each area unit alleged to perform identical perform of providing a visible variety of electronic media. Here, the crucial operational distinction is that the CRT integrates the 2 processes lightweight generation and lightweight modulation and it’s additionally managed by one set of elements. Conversely, the LCD isolates the 2 processes kind one another that’s lightweight generation and modulation.

difference between tft lcd and crt quotation

No native resolution. Currently, the only display technology capable of multi-syncing (displaying different resolutions and refresh rates without the need for scaling). Display lag is extremely low due to its nature, which does not have the ability to store image data before output, unlike LCDs, plasma displays and OLED displays.

difference between tft lcd and crt quotation

Sharp demonstrated a fourteen-inch TFT-LCD for TV in 1988 when the display size of the mass-produced TFT-LCD was three inches. The high display quality in Cathode Ray Tube size convinced other electronic companies to join the infant TFT-LCD industry aimed at emerging full-color portable PCs. Two decades later, TFT-LCDs replaced CRTs, making the vision of RCA"s LCD group in the 1960s a reality.

The milestone plaque is to be kept in Sharp Technology Innovation Museum, and shown to the public along with other milestones of Sharp business activities of a 100 year history.

Sharp Technology Innovation Museum is located in the premise of Sharp Technology Center where LCD research was started and culminated in mass-producing the world-first mini-calculator mounted with LCD and C-MOS logic : the calculator is displayed at the British Science Museum.

It showed that an ideal display, namely, a flat, low-power, light-weight, CRT-sized full-color video display ,which could be used also in high ambient light, is technologically feasible, and that is exactly what had been long waited for to be used in an emerging information age since LCD was press-released in 1968 by RCA.

3. A large mother glass scheme could work for a-Si-TFT-LCD, which was proved by the high display uniformity across the entire display area. The mother glass 300mm x 320mm was the very forerunner of the mother glass generation competition which started around 1990, 2 years after Sharp 14-in. full color TFT-LCD was demonstrated.

At the very beginning of a-Si-TFT-LCD business startup, this work clearly showed a-Si-TFT-LCD have the potential to replace monster CRT in the coming information age by its superior characteristics: flatness, light-weight, small power consumption, high saturation full-color rendition, high readability in high ambient light, realized on the 14-in. display size, the most dominant size in the contemporary market by using the technology which was developed to mass-produce twenty 3-in. TFT-LCD TV panels laid out on the mother glass of 300mm x 320mm dimensions.

TV business group knew the market and joined the development project from the very beginning and gave a clear display quality target to TFT-LCD research group to achieve and make the TFT-LCD a viable display technology against CRT dominance.

[114] T. Nagayasu, T. Oketani, T. Hirobe, H. Kato, S. Mizushima, H. Take, K. Yano, M. Hijikigawa, and I. Washizuka, “A 14-in-diagonal full color a-Si TFT LCD,” in Proc. Int. Display Research Conf., San Diego, CA, Oct. 1988, pp. 56–58.

difference between tft lcd and crt quotation

In the past decade, LCD monitors have replaced CRT screens for all but the most specialist applications. Although liquid crystal displays boast perfect