tft display meaning in hindi free sample

A thin-film-transistor liquid-crystal display (TFT LCD) is a variant of a liquid-crystal display that uses thin-film-transistor technologyactive matrix LCD, in contrast to passive matrix LCDs or simple, direct-driven (i.e. with segments directly connected to electronics outside the LCD) LCDs with a few segments.

In February 1957, John Wallmark of RCA filed a patent for a thin film MOSFET. Paul K. Weimer, also of RCA implemented Wallmark"s ideas and developed the thin-film transistor (TFT) in 1962, a type of MOSFET distinct from the standard bulk MOSFET. It was made with thin films of cadmium selenide and cadmium sulfide. The idea of a TFT-based liquid-crystal display (LCD) was conceived by Bernard Lechner of RCA Laboratories in 1968. In 1971, Lechner, F. J. Marlowe, E. O. Nester and J. Tults demonstrated a 2-by-18 matrix display driven by a hybrid circuit using the dynamic scattering mode of LCDs.T. Peter Brody, J. A. Asars and G. D. Dixon at Westinghouse Research Laboratories developed a CdSe (cadmium selenide) TFT, which they used to demonstrate the first CdSe thin-film-transistor liquid-crystal display (TFT LCD).active-matrix liquid-crystal display (AM LCD) using CdSe TFTs in 1974, and then Brody coined the term "active matrix" in 1975.high-resolution and high-quality electronic visual display devices use TFT-based active matrix displays.

The liquid crystal displays used in calculators and other devices with similarly simple displays have direct-driven image elements, and therefore a voltage can be easily applied across just one segment of these types of displays without interfering with the other segments. This would be impractical for a large display, because it would have a large number of (color) picture elements (pixels), and thus it would require millions of connections, both top and bottom for each one of the three colors (red, green and blue) of every pixel. To avoid this issue, the pixels are addressed in rows and columns, reducing the connection count from millions down to thousands. The column and row wires attach to transistor switches, one for each pixel. The one-way current passing characteristic of the transistor prevents the charge that is being applied to each pixel from being drained between refreshes to a display"s image. Each pixel is a small capacitor with a layer of insulating liquid crystal sandwiched between transparent conductive ITO layers.

The circuit layout process of a TFT-LCD is very similar to that of semiconductor products. However, rather than fabricating the transistors from silicon, that is formed into a crystalline silicon wafer, they are made from a thin film of amorphous silicon that is deposited on a glass panel. The silicon layer for TFT-LCDs is typically deposited using the PECVD process.

Polycrystalline silicon is sometimes used in displays requiring higher TFT performance. Examples include small high-resolution displays such as those found in projectors or viewfinders. Amorphous silicon-based TFTs are by far the most common, due to their lower production cost, whereas polycrystalline silicon TFTs are more costly and much more difficult to produce.

The twisted nematic display is one of the oldest and frequently cheapest kind of LCD display technologies available. TN displays benefit from fast pixel response times and less smearing than other LCD display technology, but suffer from poor color reproduction and limited viewing angles, especially in the vertical direction. Colors will shift, potentially to the point of completely inverting, when viewed at an angle that is not perpendicular to the display. Modern, high end consumer products have developed methods to overcome the technology"s shortcomings, such as RTC (Response Time Compensation / Overdrive) technologies. Modern TN displays can look significantly better than older TN displays from decades earlier, but overall TN has inferior viewing angles and poor color in comparison to other technology.

Most TN panels can represent colors using only six bits per RGB channel, or 18 bit in total, and are unable to display the 16.7 million color shades (24-bit truecolor) that are available using 24-bit color. Instead, these panels display interpolated 24-bit color using a dithering method that combines adjacent pixels to simulate the desired shade. They can also use a form of temporal dithering called Frame Rate Control (FRC), which cycles between different shades with each new frame to simulate an intermediate shade. Such 18 bit panels with dithering are sometimes advertised as having "16.2 million colors". These color simulation methods are noticeable to many people and highly bothersome to some.gamut (often referred to as a percentage of the NTSC 1953 color gamut) are also due to backlighting technology. It is not uncommon for older displays to range from 10% to 26% of the NTSC color gamut, whereas other kind of displays, utilizing more complicated CCFL or LED phosphor formulations or RGB LED backlights, may extend past 100% of the NTSC color gamut, a difference quite perceivable by the human eye.

The transmittance of a pixel of an LCD panel typically does not change linearly with the applied voltage,sRGB standard for computer monitors requires a specific nonlinear dependence of the amount of emitted light as a function of the RGB value.

In-plane switching was developed by Hitachi Ltd. in 1996 to improve on the poor viewing angle and the poor color reproduction of TN panels at that time.

Initial iterations of IPS technology were characterised by slow response time and a low contrast ratio but later revisions have made marked improvements to these shortcomings. Because of its wide viewing angle and accurate color reproduction (with almost no off-angle color shift), IPS is widely employed in high-end monitors aimed at professional graphic artists, although with the recent fall in price it has been seen in the mainstream market as well. IPS technology was sold to Panasonic by Hitachi.

Most panels also support true 8-bit per channel color. These improvements came at the cost of a higher response time, initially about 50 ms. IPS panels were also extremely expensive.

IPS has since been superseded by S-IPS (Super-IPS, Hitachi Ltd. in 1998), which has all the benefits of IPS technology with the addition of improved pixel refresh timing.

In 2004, Hydis Technologies Co., Ltd licensed its AFFS patent to Japan"s Hitachi Displays. Hitachi is using AFFS to manufacture high end panels in their product line. In 2006, Hydis also licensed its AFFS to Sanyo Epson Imaging Devices Corporation.

It achieved pixel response which was fast for its time, wide viewing angles, and high contrast at the cost of brightness and color reproduction.Response Time Compensation) technologies.

Less expensive PVA panels often use dithering and FRC, whereas super-PVA (S-PVA) panels all use at least 8 bits per color component and do not use color simulation methods.BRAVIA LCD TVs offer 10-bit and xvYCC color support, for example, the Bravia X4500 series. S-PVA also offers fast response times using modern RTC technologies.

When the field is on, the liquid crystal molecules start to tilt towards the center of the sub-pixels because of the electric field; as a result, a continuous pinwheel alignment (CPA) is formed; the azimuthal angle rotates 360 degrees continuously resulting in an excellent viewing angle. The ASV mode is also called CPA mode.

A technology developed by Samsung is Super PLS, which bears similarities to IPS panels, has wider viewing angles, better image quality, increased brightness, and lower production costs. PLS technology debuted in the PC display market with the release of the Samsung S27A850 and S24A850 monitors in September 2011.

TFT dual-transistor pixel or cell technology is a reflective-display technology for use in very-low-power-consumption applications such as electronic shelf labels (ESL), digital watches, or metering. DTP involves adding a secondary transistor gate in the single TFT cell to maintain the display of a pixel during a period of 1s without loss of image or without degrading the TFT transistors over time. By slowing the refresh rate of the standard frequency from 60 Hz to 1 Hz, DTP claims to increase the power efficiency by multiple orders of magnitude.

Due to the very high cost of building TFT factories, there are few major OEM panel vendors for large display panels. The glass panel suppliers are as follows:

External consumer display devices like a TFT LCD feature one or more analog VGA, DVI, HDMI, or DisplayPort interface, with many featuring a selection of these interfaces. Inside external display devices there is a controller board that will convert the video signal using color mapping and image scaling usually employing the discrete cosine transform (DCT) in order to convert any video source like CVBS, VGA, DVI, HDMI, etc. into digital RGB at the native resolution of the display panel. In a laptop the graphics chip will directly produce a signal suitable for connection to the built-in TFT display. A control mechanism for the backlight is usually included on the same controller board.

The low level interface of STN, DSTN, or TFT display panels use either single ended TTL 5 V signal for older displays or TTL 3.3 V for slightly newer displays that transmits the pixel clock, horizontal sync, vertical sync, digital red, digital green, digital blue in parallel. Some models (for example the AT070TN92) also feature input/display enable, horizontal scan direction and vertical scan direction signals.

New and large (>15") TFT displays often use LVDS signaling that transmits the same contents as the parallel interface (Hsync, Vsync, RGB) but will put control and RGB bits into a number of serial transmission lines synchronized to a clock whose rate is equal to the pixel rate. LVDS transmits seven bits per clock per data line, with six bits being data and one bit used to signal if the other six bits need to be inverted in order to maintain DC balance. Low-cost TFT displays often have three data lines and therefore only directly support 18 bits per pixel. Upscale displays have four or five data lines to support 24 bits per pixel (truecolor) or 30 bits per pixel respectively. Panel manufacturers are slowly replacing LVDS with Internal DisplayPort and Embedded DisplayPort, which allow sixfold reduction of the number of differential pairs.

Backlight intensity is usually controlled by varying a few volts DC, or generating a PWM signal, or adjusting a potentiometer or simply fixed. This in turn controls a high-voltage (1.3 kV) DC-AC inverter or a matrix of LEDs. The method to control the intensity of LED is to pulse them with PWM which can be source of harmonic flicker.

The bare display panel will only accept a digital video signal at the resolution determined by the panel pixel matrix designed at manufacture. Some screen panels will ignore the LSB bits of the color information to present a consistent interface (8 bit -> 6 bit/color x3).

With analogue signals like VGA, the display controller also needs to perform a high speed analog to digital conversion. With digital input signals like DVI or HDMI some simple reordering of the bits is needed before feeding it to the rescaler if the input resolution doesn"t match the display panel resolution.

The statements are applicable to Merck KGaA as well as its competitors JNC Corporation (formerly Chisso Corporation) and DIC (formerly Dainippon Ink & Chemicals). All three manufacturers have agreed not to introduce any acutely toxic or mutagenic liquid crystals to the market. They cover more than 90 percent of the global liquid crystal market. The remaining market share of liquid crystals, produced primarily in China, consists of older, patent-free substances from the three leading world producers and have already been tested for toxicity by them. As a result, they can also be considered non-toxic.

Kawamoto, H. (2012). "The Inventors of TFT Active-Matrix LCD Receive the 2011 IEEE Nishizawa Medal". Journal of Display Technology. 8 (1): 3–4. Bibcode:2012JDisT...8....3K. doi:10.1109/JDT.2011.2177740. ISSN 1551-319X.

Brody, T. Peter; Asars, J. A.; Dixon, G. D. (November 1973). "A 6 × 6 inch 20 lines-per-inch liquid-crystal display panel". 20 (11): 995–1001. Bibcode:1973ITED...20..995B. doi:10.1109/T-ED.1973.17780. ISSN 0018-9383.

Richard Ahrons (2012). "Industrial Research in Microcircuitry at RCA: The Early Years, 1953–1963". 12 (1). IEEE Annals of the History of Computing: 60–73. Cite journal requires |journal= (help)

K. H. Lee; H. Y. Kim; K. H. Park; S. J. Jang; I. C. Park & J. Y. Lee (June 2006). "A Novel Outdoor Readability of Portable TFT-LCD with AFFS Technology". SID Symposium Digest of Technical Papers. AIP. 37 (1): 1079–82. doi:10.1889/1.2433159. S2CID 129569963.

Kim, Sae-Bom; Kim, Woong-Ki; Chounlamany, Vanseng; Seo, Jaehwan; Yoo, Jisu; Jo, Hun-Je; Jung, Jinho (15 August 2012). "Identification of multi-level toxicity of liquid crystal display wastewater toward Daphnia magna and Moina macrocopa". Journal of Hazardous Materials. Seoul, Korea; Laos, Lao. 227–228: 327–333. doi:10.1016/j.jhazmat.2012.05.059. PMID 22677053.

The digital age has ushered in a whole host of new display technologies. The TFT LCD screens they are one of those technologies that have revolutionized the electronic device industry in recent years. These new displays have made it possible for manufacturers to deliver innovative user interfaces, fast response times, and sharp images on a wide variety of devices, from TVs to smartphones and everything in between.

This article will guide you in the world of TFT LCD screens. TFT stands for Thin Film Transistor Liquid Crystal Display (thin-film transistor liquid crystal display), while LCD refers to its general use in most electronic devices such as televisions, computer monitors, and projectors, among others. If you"re familiar with the basics of these display technologies, you"re halfway there.

A TFT LCD screen is athin film transistor electronic display (TFT). This means that just like a normal LCD screen, this screen also uses a liquid crystal material. However, the key difference between a typical LCD and a TFT LCD is the way the liquid crystal material is used in a TFT LCD. Unlike a normal LCD screen, which works by turning the voltage across the liquid crystal material on and off, a TFT has a digital control circuit. This switch-type control allows the screen to display images, including text and graphics.

active matrix: Active matrix TFT LCD displays use a thin layer of liquid crystal material sandwiched between two layers of thin transparent electrodes. A thin transparent conductive film is inserted between these electrodes and acts as a switch. When a voltage is applied across these electrodes, the liquid crystal material is forced to change its polarization state, causing a change in its optical properties. This property is used to turn pixels on and off to produce an image.

Passive matrix: In passive matrix TFT LCD displays, the liquid crystal panel is sandwiched between two glass plates. When a voltage is applied between the two electrodes of the glass, the electrodes change to conductive states and the liquid crystal changes from one state to another. In this way, the pixels are controlled by the panel itself.

good soda rate: Refresh rate refers to the speed at which a digital screen can display new images. For example, most CRT televisions display images at a refresh rate of 60 Hz. This means that the image displayed on the screen is updated 60 times per second. With new technologies, such as LCDs, this refresh rate has been reduced to 244 Hz, which means that the images displayed on the screen are refreshed only 244 times per second. In most cases, a refresh rate of at least 60 Hz is needed to deliver acceptable image quality. A screen with a refresh rate lower than that looks jagged and blurry.

Wide viewing angle: Unlike CRT televisions that display images with a narrow viewing angle, modern LCDs are capable of displaying images with a wide viewing angle. This means that you can view the images with your colleagues and friends from a wide angle without the image quality being affected.

Compact size: Being flat, the size is much more compact and thin compared to a CRT screen. Also, CRTs don"t usually come in such a wide variety of sizes, both the big ones and the smaller ones are just for LCDs.

Cost: The main advantage of an LCD screen is its low production cost. Compared to the production cost of a TFT, an LCD costs less, making it a more accessible display technology for the masses. However, there have recently been a number of advances in microlens technology that have made it possible to manufacture high-quality displays at a relatively low production cost.

As you can see, they are not overly expensive and allow you to carry out many projects with Arduino. And not only that, you can also join them to other different projects, including SBCs like the Raspberry Pi. Versatility is very high, the limit is your imagination.

The term ‘TFT’ stands for Thin Film Transistor. TFT is widely used in LCD screens to make the images look brighter. It is an active element that works in collaboration with the pixels. The image we see on the screens is made of millions of picture grids of pixels, a smaller unit of the picture. LCD screen images involve a TFT for each pixel so that the pixels can be switched off and on altogether.

Thin Film Transistor works in an apt way that allows the screen to refresh swiftly. In other words, TFT"s full meaning works as an individual switch that controls the pixels as per requirements. LCD or liquid crystal display is an up to date display technology that claims to offer crystal clear images to the viewers. With the implementation of TFT, the photos come out to look brighter and clearer.

Bernard Lechner first presented the idea of the full meaning of TFT. He was the first person to offer the idea of running the pixels in strong collaboration with TFT technology. Bernard approached his concept at the RCA"s Press conference held in 1968. He also suggested arranging the TFT in the order of the matrix.

Without TFT abbreviation technology, there will be no advancement in the field of display technology. The speciality of an LCD display is the millions of pixels that work altogether. Without a Thin Film Transistor technology, you won’t be able to receive clear and sharp images. In recent times, most of the display technologies are depending on the application of TFT.

TFT full meaning or Thin Film Transistor can be stated as a bundle of switches that work in coordination with the pixels in the order of the matrix. This technology mainly focuses on changing and refreshing the pixels to bring a quick change to the screen. Without this technology, the images won’t be so clear.

Up-to-date TFT technology is highly beneficial to the human eye. If you look at a screen with an inferior display system for a long time, it can hamper your eyesight. The images on the screen are made after assembling millions of pixels. If the pixels are not supported by any high-Quality system then it will damage your eyesight.

The LCD is abbreviated for liquid crystal display. It is a kind of flat panel display that uses liquid crystals in its primary form of operation. The invention of LCDs has led to the start of various businesses and new products. The LCD can be seen now in smartphones, televisions, instrument panels as well as computer screens.

The invention of LCD has led to the replacement of old methods of displays like gas plasma displays and light-emitting diodes(LED). Because the LCDs are designed to work to block the light rather than emit it, they consume much less power than LEDs and gas displays.

During the manufacturing or after the use, the dead pixels or stuck pixels might occur, which leads to pixels glowing even on a fully black screen or remaining dead even when the screen is glowing.

When the screen is on for a long time, thermalisation might take place leading to the screen getting discoloured in that particular area of the screen.

OLEDs stand for organic light-emitting diodes. In technology today, LCDs are being replaced by modern OLEDs. The LCDs are still in use. The OLEDs comprise a single panel whereas the LCDs are made up of two panels. Like an LCD, the OLEDs do not need backlighting. They are much thinner than LCDs and also are much deeper in black.

The QLEDS are also known as quantum light-emitting diodes as well as quantum dot LED. The company called Samsung first developed the QLEDs and the very newer version of television sets are made of a QLED screen. These kinds of screens are usually similar to LCDs. When a quantum dot film is added to an LCD, it"s called QLED, This adding a layer accounts for the improvement in the display, colour and brightness of the picture quality. The main component of QLED is small crystal semiconductor particles. These semiconductor particles can also be controlled for the output of the screen"s colour.

All the three displays, that is LCD, QLED and OLEDs have their own set of advantages and disadvantages. The QLED is smaller in size, thinner as well as financially feasible compared to that of other options.

apron means a defined area, intended to accommodate aircraft for purposes of loading or unloading passengers, mail or cargo, fuelling, parking or maintenance;

TMDL means the total maximum daily load limitation of a parameter, representing the estimated assimilative capacity for a water body before other designated uses are adversely affected. Mathematically, it is the sum of wasteload allocations for point sources, load allocations for non-point and natural background sources, and a margin of safety.

SDSL or "Symmetric Digital Subscriber Line" is a baseband DSL transmission technology that permits the bi-directional transmission from up to 160 kbps to 2.048 Mbps on a single pair. "VDSL" or "Very High Speed Digital Subscriber Line" is a baseband DSL transmission technology that permits the transmission of up to 52 Mbps downstream (from the Central Office to the End User Customer) and up to 2.3 Mbps digital signal upstream (from the End User Customer to the Central Office). VDSL can also be 26 Mbps symmetrical, or other combination.

NBOME means the National Board of Osteopathic Medical Examiners, an organization that prepares and administers qualifying examinations for osteopathic physicians.

ATC means a measure of the transfer capability remaining in the physical transmission network for further commercial activity over and above already committed uses.

MECAB refers to the Multiple Exchange Carrier Access Billing document prepared by the Billing Committee of the Ordering and Billing Forum “OBF”, which functions under the auspices of the Carrier Liaison Committee “CLC of the Alliance for Telecommunications Industry Solutions “ATIS”. The MECAB document, published by ATIS as ATIS/OBF- MECAB- Issue 6, February 1998, contains the recommended guidelines for the billing of access services provided to an IXC by two or more LECs, or by one LEC in two or more states within a single LATA.

SFTR means Regulation EU 2015/2365 of the European Parliament and of the Council on transparency of securities financing transactions and of reuse and amending Regulation (EU) No 648/2012 as may be modified, amended, supplemented, consolidated or re-enacted from time to time;

Full Research Report On Global TFT LCD Display Modules Market Analysis available at: https://www.millioninsights.com/industry-reports/tft-lcd-display-modules-market

Even as the Indian Evidence Act, as amended in 2002, clearly prohibited a reference to the sexual history of a victim of sexual assault, which required the TFT and the Supreme Court called such a test as "hypothetical" and "opinionative" nearly a decade ago, thanks to the efforts of activists, the horrendous quality of the forensic medical examination for victims of sexual assaults is bound to change for the better.

TFT has been offering aviation course such as pilot training, flight attendant training and has supplied aviation personnel to THAI and other carriers for a period of time already.

Sony and SMD plan to increase efficiency and strengthen operations in the small- and medium-sized TFT LCD business by concentrating manufacturing operations going forward in SMD"s Higashiura Plant and SMD"s Tottori Plant* (to be established on April 1, 2010.) By producing a wide range of technically advanced and cost-effective products, and offering comprehensive product lineups that fully utilize its strengths in small- and medium-sized TFT LCD sales, engineering and product design, Sony aims to enhance its customer relationships and strengthen the competitiveness of its small- and medium-sized TFT LCD business to continue to meet and exceed customer needs.

""By producing a wider range of technically advanced and cost-effective products, and offering comprehensive small- and medium-sized TFT LCD product lineups, the Sony group expects to enhance its customer relationships and strengthen the competitiveness of its small- and medium-sized TFT LCD business,"" they said.

If you want to buy a new monitor, you might wonder what kind of display technologies I should choose. In today’s market, there are two main types of computer monitors: TFT LCD monitors & IPS monitors.

The word TFT means Thin Film Transistor. It is the technology that is used in LCD displays.  We have additional resources if you would like to learn more about what is a TFT Display. This type of LCDs is also categorically referred to as an active-matrix LCD.

These LCDs can hold back some pixels while using other pixels so the LCD screen will be using a very minimum amount of energy to function (to modify the liquid crystal molecules between two electrodes). TFT LCDs have capacitors and transistors. These two elements play a key part in ensuring that the TFT display monitor functions by using a very small amount of energy while still generating vibrant, consistent images.

Industry nomenclature: TFT LCD panels or TFT screens can also be referred to as TN (Twisted Nematic) Type TFT displays or TN panels, or TN screen technology.

IPS (in-plane-switching) technology is like an improvement on the traditional TFT LCD display module in the sense that it has the same basic structure, but has more enhanced features and more widespread usability.

These LCD screens offer vibrant color, high contrast, and clear images at wide viewing angles. At a premium price. This technology is often used in high definition screens such as in gaming or entertainment.

Both TFT display and IPS display are active-matrix displays, neither can’t emit light on their own like OLED displays and have to be used with a back-light of white bright light to generate the picture. Newer panels utilize LED backlight (light-emitting diodes) to generate their light hence utilizing less power and requiring less depth by design. Neither TFT display nor IPS display can produce color, there is a layer of RGB (red, green, blue) color filter in each LCD pixels to produce the color consumers see. If you use a magnifier to inspect your monitor, you will see RGB color in each pixel. With an on/off switch and different level of brightness RGB, we can get many colors.

Wider viewing angles are not always welcome or needed. Image you work on the airplane. The person sitting next to you always looking at your screen, it can be very uncomfortable. There are more expensive technologies to narrow the viewing angle on purpose to protect the privacy.

Winner. IPS TFT screens have around 0.3 milliseconds response time while TN TFT screens responds around 10 milliseconds which makes the latter unsuitable for gaming

Winner. the images that IPS displays create are much more pristine and original than that of the TFT screen. IPS displays do this by making the pixels function in a parallel way. Because of such placing, the pixels can reflect light in a better way, and because of that, you get a better image within the display.

As the display screen made with IPS technology is mostly wide-set, it ensures that the aspect ratio of the screen would be wider. This ensures better visibility and a more realistic viewing experience with a stable effect.

Winner. While the TFT LCD has around 15% more power consumption vs IPS LCD, IPS has a lower transmittance which forces IPS displays to consume more power via backlights. TFT LCD helps battery life.

Normally, high-end products, such as Apple Mac computer monitors and Samsung mobile phones, generally use IPS panels. Some high-end TV and mobile phones even use AMOLED (Active Matrix Organic Light Emitting Diodes) displays. This cutting edge technology provides even better color reproduction, clear image quality, better color gamut, less power consumption when compared to LCD technology.

What you need to choose is AMOLED for your TV and mobile phones instead of PMOLED. If you have budget leftover, you can also add touch screen functionality as most of the touch nowadays uses PCAP (Projective Capacitive) touch panel.

This kind of touch technology was first introduced by Steve Jobs in the first-generation iPhone. Of course, a TFT LCD display can always meet the basic needs at the most efficient price. An IPS display can make your monitor standing out.

Thanks for the display technology development, we have a lot of display choices for our smartphones, media players, TVs, laptops, tablets, digital cameras, and other such gadgets. The most display technologies we hear are LCD, TFT, OLED, LED, QLED, QNED, MicroLED, Mini LED etc. The following, we will focus on two of the most popular display technologies in the market: TFT Displays and Super AMOLED Displays.

TFT means Thin-Film Transistor. TFT is the variant of Liquid Crystal Displays (LCDs). There are several types of TFT displays: TN (Twisted Nematic) based TFT display, IPS (In-Plane Switching) displays. As the former can’t compete with Super AMOLED in display quality, we will mainly focus on using IPS TFT displays.

OLED means Organic Light-Emitting Diode. There are also several types of OLED, PMOLED (Passive Matrix Organic Light-Emitting Diode) and AMOLED (Active Matrix Organic Light-Emitting Diode). It is the same reason that PMOLED can’t compete with IPS TFT displays. We pick the best in OLED displays: Super AMOLED to compete with the LCD best: IPS TFT Display.

If you have any questions about Orient Display displays and touch panels. Please feel free to contact: Sales Inquiries, Customer Service or Technical Support.

Corresponding Author: Michael T. Sheehan, MD, Marshfield Clinic – Weston Center, Department of Endocrinology, 3501 Cranberry Boulevard, Weston, WI 54476 USA, Tel: (715) 393-1366, Email: gro.cinilcdleifhsram@leahcim.naheehs

Disorders of thyroid function are common, and screening, diagnosis, and management are often performed by primary care providers. While management of significant biochemical abnormalities is reasonably straight forward, laboratory tests only slightly outside, or even within, the normal range are becoming more difficult to appropriately manage. A large part of this increasing difficulty in appropriate management is caused by patients requesting, and even demanding, certain tests or treatments that may not be indicated. Symptoms of thyroid dysfunction are non-specific and extremely prevalent in the general population. This, along with a growing body of information available to patients via the lay press and internet suggesting that traditional thyroid function testing is not reliable, has fostered some degree of patient mistrust. Increasingly, when a physician informs a patient that their thyroid is not the cause of their symptoms, the patient is dissatisfied and even angry. This review aims to clarify the interpretation of normal and mild abnormalities of thyroid function tests by describing pituitary-thyroid physiology and through an in depth review of, arguably, the three most important biochemical tests of thyroid function: TSH, free T4, and anti-TPO antibodies. It is important for primary care providers to have an understanding of the shortcomings and proper interpretation of these tests to be better able to discuss thyroid function with their patients.

Functional disorders of the thyroid (hypothyroidism and hyperthyroidism) are common and, in many cases, managed by primary care providers. In addition to diagnosed cases, there are many patients who present to their provider seeking evaluation of their thyroid status as a possible cause of a variety of complaints including obesity, mood changes, hair loss, and fatigue. There is an ever-growing body of literature in the public domain, whether in print or internet-based, suggesting that thyroid conditions are under-diagnosed by physicians and that standard thyroid function tests are unreliable. Primary care providers are often the first to evaluate these patients and order biochemical testing. This has become a more complex process, with many patients requesting and even demanding certain biochemical tests that may not be indicated. This review aims to describe three important biochemical tests of thyroid status (thyroid stimulating hormone [TSH], free thyroxine [free T4], and anti-thyroid peroxidase antibodies [anti-TPO ABs]) the primary care provider should be comfortable not only ordering and interpreting, but also not ordering in many circumstances. Discussion will include the indications, utility, and potential short-comings of these tests in relation to the scrutiny that has been placed on their accuracy and validity by a growing number of patients.

The proper interpretation of thyroid function tests requires an understanding of thyroid physiology. Thyroid function is regulated by a relatively straightforward relationship between the hypothalamus, pituitary, and the thyroid gland itself (figure 1). Thyrotropin releasing hormone (TRH) from the hypothalamus stimulates the release of TSH from the pituitary gland which, in turn, regulates a variety of steps in the production of thyroid hormones from the uptake of iodine to the regulation of enzymatic steps in the process. The majority of thyroid hormone released by the gland (~ 85%) is thyroxine (T4), while a smaller proportion (~15%) is tri-iodothyronine (T3). These thyroid hormones are highly protein-bound (99.8%), with only the free components (free T3 and free T4) having the ability to bind to their respective receptors. The active thyroid hormone is free T3, and there is tissue-specific regulation of the conversion of T4 to T3 by a set of deiodinase enzymes peripherally allowing each tissue to, in a sense, self-regulate its exposure to free T3. This is crucial, because different tissues require different levels of T3. This conversion of T4 to T3 is how treatment of hypothyroidism with levothyroxine (T4 only) still allows for adequate, tissue-specific, T3 exposure.

Next, it is essential to appreciate the negative feedback of free T3 and free T4 at the level of the hypothalamus and pituitary (see figure 1). Also, the relationship between these thyroid hormones and TSH is not linear but log-linear, such that very small changes in free T3 and/or free T4 will result in very large changes in TSH. Conversely, very small changes in TSH reflect extremely minute changes in free T3 and free T4. For instance, a 2-fold change in free T4 will result in a 100-fold change in TSH. Thus, a free T4 change from 1.0 ng/dL to 0.5 ng/dL will result in a TSH rise from 0.5 mIU/mL to 50 mIU/mL. On the other hand, a rise in TSH from 1.0 mIU/mL to 5.0 mIU/mL reflects a drop in free T4 from 1.0 ng/dL to just 0.9 ng/dL. It is also important to note that each individual has a set point for their own free T3 and free T4 level that is quite stable in the absence of disease. Therefore, changes in any given patient’s free T3 and/or free T4 within the normal range will result in an abnormal TSH value. This supports the role of TSH, in the absence of hypothalamic/pituitary disease, as the most sensitive marker of thyroid function. Table 1 lists common patterns of thyroid function tests and their interpretation, assuming an intact hypothalamic-pituitary-thyroid axis and the absence of significant non-thyroidal illness. These interpretations will be valid in the vast majority of non-hospitalized patients presenting to the primary care provider.

As mentioned previously, thyroid function tests can be difficult to reliably interpret in patients who are acutely ill, and the severity of the illness plays a role as well. As such, thyroid function tests should be interpreted with extreme caution in hospitalized patients and in those recently discharged from the hospital. The term used to describe these non-specific effects on thyroid function tests is non-thyroidal illness (previously termed euthyroid sick syndrome). An in depth discussion of the pathophysiology of non-thyroidal illness is beyond the scope of this review, but the interested reader is referred to a recent summary by Farwell.

Assessment of TSH is the single most useful test of thyroid function in the vast majority of patients. Primary care providers should seldom need to order any other biochemical thyroid test. In most cases the TSH will be within the normal range, and no further testing is indicated. However, providers should be aware of several important issues in the interpretation of a TSH value. The importance of these issues is mainly that any clinical decision should not be made (in a non-pregnant patient) based on a single TSH value if it is within or close to the normal range.

Considerable literature exists regarding what the normal range for TSH really should be, and this topic is covered at length in recent reviewsth to 97.5th percentiles of the distribution of values measured in the population tested. Therefore, 2.5% of people with completely normal thyroid function will have a TSH slightly below the listed normal range (and 2.5% slightly above the normal range).

While there may be slight differences in TSH reference ranges based on race,th percentile was 3.5 mIU/mL for 20–29 year olds increasing to 4.5 mIU/mL for 50–70 year olds and 7.5 mIU/mL for those over the age of 80 years. This age-related increase in TSH may be an adaptive mechanism, as there is evidence showing increased mortality in advanced age as TSH declines within the normal range.

Pregnancy is the one circumstance wherein initiation or adjustment of replacement therapy with L-T4 is indicated for a TSH within the upper normal range.

It is not generally appreciated by primary care providers that TSH secretion follows a circadian rhythm, with maximal levels seen in the early morning and a nadir in the late afternoon to mid-evening.am had a normal TSH (< 4.0 mIU/mL) when assessed between 2:00–4:00 pm.

Also underappreciated is the individual variation in TSH that occurs for no apparent reason. In a study assessing TSH values monthly for one year in healthy men, this apparent random variation occurred with a mean TSH of 0.75 mIU/mL and a range of 0.2–1.6 mIU/mL.

The definition of subclinical hypothyroidism is a mildly elevated TSH (4.6–8.0 mIU/mL) in the setting of a normal free T4. This biochemical finding may or may not be accompanied by mild symptoms of hypothyroidism. The difficultly in determining which, if any, symptoms are truly related is the non-specific nature of the symptoms of hypothyroidism and the high prevalence of many of these same complaints in the general population. Indeed, approximately 67% of the U.S. population is overweight or obese,

That being said, the prevalence of subclinical hypothyroidism is quite high at between 3.9% and 8.5% (versus the 0.2%–0.4% prevalence of overt hypothyroidism).

Subclinical hyperthyroidism is defined as a mildly suppressed TSH (generally still > 0.1 mIU/mL) in a patient without overt symptoms of hyperthyroidism. The primary care provider will see fewer of these patients owing to the lower prevalence of between 0.2–0.9%.

As already described, the reliable interpretation of thyroid function tests requires an intact hypothalamic-pituitary-thyroid axis. Thankfully, disruption of this hormonal axis is uncommon to rare and, when present is usually already diagnosed (ie, a patient with a history of a pituitary macroadenoma). The main concern of the primary care provider, then, is to know the prevalence of undiagnosed hypothalamic/pituitary disease causing hypothyroidism. Population-based data on this subject is limited, but Regal et al

While pituitary microadenoma is quite common (~10% of the population), the vast majority of these small tumors are not large enough to adversely affect normal pituitary function. The prevalence of pituitary macroadenoma, based on data from magnetic resonance imaging (MRI) studies showing incidentally discovered lesions, has been estimated at between 0.16–0.2%.

The prevalence of empty sella can also be estimated based on incidental discovery on MRI imaging. In a study of 500 consecutive subjects undergoing MRI of the brain, Foresti et al

As has been demonstrated, the prevalence of previously undiagnosed central hypothyroidism causing a normal TSH is impossible to estimate reliably. All things considered, perhaps 0.05–0.1% (about 1 case per 1500 patients) may be a reasonable approximation. While price varies widely, a free T4 level may cost between $55 US to $108 US. Assuming proper diagnosis could be based on a single free T4 level documented below the normal range, it would cost between $82,500 US and $162,000 US to identify a single case of undiagnosed central hypothyroidism. This brings up significant issues in terms of the cost-effectiveness of adding a free T4 to confirm the reliability of a normal TSH result.

There are several other possible situations in which a normal TSH may not reflect euthyroidism. These conditions are all quite rare and, thus, will not be discussed at length. The presence of heterophile antibodies (produced as a result of close contact with animals) can potentially interfere with the TSH assay, causing either a falsely high or falsely low result.Table 2 lists the pattern of thyroid function tests and prevalence of the conditions that might result in a falsely normal TSH.

Beyond the TSH, assessment of free T4 is the most commonly ordered thyroid function test. In the United States alone, approximately 18 million free T4 tests were performed in 2008 compared to approximately 59 million TSH tests.

An important point to make about the assessment of free T4 (beyond whether it is even indicated) is the reliability of the result. The accuracy of free T4 is highly dependent upon the assay employed, and unfortunately, the assay used in the vast majority of laboratories may not be terribly reliable. While the inter-assay precision of free T4 assays is generally good (~4.3% in our laboratory), the accuracy of that result may be poor. Indeed, in one survey of 13 free T4 methods, four of them had more than 50% of the results NOT meeting the allowable inaccuracy criteria.

Most laboratories utilize the direct analog immunoassay (IA) for the measurement of free T4, and again the validity of the results are debated and poorly standardized.Table 3 lists the limited indications for which a free T4 test should be ordered.

Thyroid peroxidase is one of the key enzymes involved in the synthesis of T3 and T4, catalyzing several steps in the process. The presence of anti-TPO ABs is a hallmark of autoimmune thyroid disease, especially Hashimoto’s thyroiditis, but also being highly prevalent in postpartum thyroiditis and Graves’ disease.

One instance where assessment of anti-TPO AB is recommended (even when the TSH is normal) is in some women in relation to pregnancy or planned pregnancy. Because of the importance of maintaining euthyroidism in pregnancy, the pre-conception identification of women at risk for hypothyroidism is essential. However, this does not mean that all women should have anti-TPO ABs testing preconception. Rather, just those women at higher risk for autoimmune thyroid disease, such as those with a family history of thyroid disease or a personal history of other autoimmune disease (such as type 1 diabetes or Addison’s disease), should be tested. Another instance in which assessment of anti-TPO ABs is recommended is in the setting of infertility and/or recurrent miscarriage—grade “A” in clinical guidelines.

There are many other tests of thyroid status that can be ordered by providers beyond the three discussed in this review. However, it should be noted that these remaining tests are seldom needed, even by endocrinologists outside of very well-defined clinical scenarios. Again, the only test of thyroid function needed by the vast majority of patients seen in primary care is the TSH, despite what patients themselves may request or demand. Table 4 lists these other thyroid tests and their main clinical use.

Thyroid stimulating immunoglobulin & TSH receptor antibodiesEvaluation of the cause of hyperthyroidism (used in conjunction with thyroid uptake and scan and/or at times when radioiodine scanning cannot be performed (i.e. pregnancy))

Primary hypothyroidism is one of the most common endocrine disorders encountered and managed by primary care providers. Unfortunately, the symptoms of hypothyroidism are extremely non-specific and otherwise highly prevalent in the population. Therefore, providers need to rely on biochemical testing to confirm or rule-out the diagnosis of hypothyroidism. This long-standing reliance on the TSH has come under increased scrutiny in the public domain, and many alternative and traditional medicine providers are now questioning the reliability of standard biochemical testing of thyroid function. Many patients struggle with a multitude of these non-specific complaints, and in their quest for answers become upset when they are told their thyroid function is normal. As reviewed, true hypothyroidism in the setting of a normal TSH is highly unlikely, with an estimated prevalence of perhaps 1 case per 1500 patients. It is uncertain, therefore, whether the assessment of a single free T4 is cost-effective in the assessment of a patient’s thyroid status. If a free T4 test is obtained, the limitations of the assay method employed need to be considered. Lastly, the assessment of anti-TPO ABs should be avoided in non-pregnant patients with a normal TSH, as treatment decisions based on the presence or absence of these antibodies is not supported by current clinical guidelines. The increasingly maligned TSH is still the best, and often only, thyroid function test that is needed in the assessment of most patients.

4. Garber JR, Cobin RH, Gharib H, Hennessey JV, Klein I, Mechanick JI, Pessah-Pollack R, Singer PA, Woeber KA; American Association of Clinical Endocrinologists and American Thyroid Association Taskforce on Hypothyroidism in Adults. Clinical practice guidelines for hypothyroidism in adults: cosponsored by the American Association of Clinical Endocrinologists and the American Thyroid Association. Endocr Pract

Serum TSH, T(4), and thyroid antibodies in the United States population (1988 to 1994): National Health and Nutrition Examination Survey (NHANES III). J Clin Endocrinol Metab

Narrow individual variations in serum T(4) and T(3) in normal subjects: a clue to the understanding of subclinical thyroid disease. J Clin Endocrinol Metab

Spontaneous subclinical hypothyroidism in patients older than 55 years: an analysis of natural course and risk factors for the development of overt thyroid failure. J Clin Endocrinol Metab

Non-functioning pituitary adenomas: clinical feature, laboratorial and imaging assessment, therapeutic management and outcome. Arq Bras Endocrinol Metabol

34. Guitelman M, Garcia Basavilbaso N, Vitale M, Chervin A, Katz D, Miragaya K, Herrera J, Cornalo D, Servidio M, Boero L, Manavela M, Danilowicz K, Alfieri A, Stalldecker G, Glerean M, Fainstein Day P, Ballarino C, Mallea Gil MS, Rogozinski A.

Medications that distort in vitro tests of thyroid function, with particular reference to estimates of serum free thyroxine. Best Pract Res Clin Endocrinol Metab

45. Thienpont LM, Beastall G, Christofides ND, Faix JD, Leiri T, Miller WG, Miller R, Nelson JC, Ross HA, Ronin C, Rottmann M, Thijssen JH, Toussaint B.

International federation of clinical chemistry and laboratory medicine (IFCC), Scientific division working group for standardization of thyroid function tests (WG-STFT). Measurement of free thyroxine in laboratory medicine: proposal of measurand definition. Clin Chem Lab Med

46. Thienpont LM, Beastall G, Christofides ND, Faix ID, leiri T, Jarrige V, Miller WG, Nelson JC, Ronin C, Ross HA, Rottmann M, Thijssen JH, Toussaint B.

IFCC scientific division working group for standardization of thyroid function tests (WG-STFT). Proposal of a candidate international conventional reference measurement procedure for free thyroxine in serum. Clin Chem Lab Med

47. Thienpont LM, Van Uytfanghe K, Beastall G, Faix JD, Ieiri T, Miller WG, Nelson JC, Ronin C, Ross HA, Thijssen JH, Toussaint B; IFCC Working Group on Standardization of Thyroid Function Tests. Report of the IFCC Working Group for Standardization of Thyroid Function Tests; part 2: free thyroxine and free triiodothyronine. Clin Chem

Inverse log-linear relationship between thyroid-stimulating hormone and free thyroxine measured by direct analog immunoassay and tandem mass spectrometry. Clin Chem

Thyroid peroxidase antibody in women with unexplained recurrent miscarriage: prevalence, prognostic value, and response to empirical thyroxine therapy. Fertil Steril

Focus Displays offers a wide range of standard full color TFT displays. 64 million unique colors, high brightness, sharp contrast, -30C operating temperature, and fast response time are all good descriptions of a TFT display. This is why TFT technology is one of the most popular choices for a new product.

Thin Film Transistor (TFT) display technology can be seen in products such as laptop computers, cell phones, tablets, digital cameras, and many other products that require color. TFT’s are active matrix displays which offers exceptional viewing experiences especially when compared to other passive matrix technologies. The clarity on TFT displays is outstanding; and they possess a longer half-life than some types of OLEDs and range in sizes from less than an inch to over 15 inches.

Cold-Cathode Fluorescent Lamp (CCFL) is an AC driven backlight that requires an inverter to convert DC to AC. The AC signal and inverter may generate EMI (Electromagnetic interference) and arcing; Arcing must be eliminated for Intrinsically Safe products.

CCFL’s are still available, but are becoming a legacy (obsolete) component. TFT displays equipped with a CCFL require higher MOQs (Minimum Order Quantities) than displays with LED backlights.

Red, Green and Blue (RGB) backlights are built with either a single LED that produces red, green and blue colors or with three separate Red, Green or Blue LEDs.

RGB backlights require a controller to regulate the different intensities of each color. The controller’s function is to combine unique levels of Red, Green and Blue to produce any of 64M different colors.

Backlight brightness (Luminance) is measured in nits. A nit being the amount of light that one candle delivers in a 1 square meter box. The intensity of the LED backlight can be critical when operating in low light or in direct sun light and is usually controlled by adjusting the DC voltage. In many applications this is accomplished through pulse-width modulation (PWM)

The majority of TFT displays contain a touch panel, or touch screen. The touch panel is a touch-sensitive transparent overlay mounted on the front of the display glass. Allowing for interaction between the user and the LCD display.

Some touch panels require an independent driver IC; which can be included in the TFT display module or placed on the customer’s Printed Circuit Board (PCB). Touch screens make use of coordinate systems to locate where the user touched the screen.

Resistive touch panels are the lowest cost option and are standard equipment on many TFT modules. They are more common on smaller TFT displays, but can still be incorporated on larger modules.

Resistive touch panels are constructed using flexible materials with an air gap between and are coated with a resistive layer. When an object applies pressure to the top layer, it makes contact with microdots located on the bottom layer. This allows the touch screen to find the location of the touch using X and Y coordinates.

Custom resistive touch screens are an option if the customer requires a seal or gasket to be in contact with the glass and not in contact with the touch panel.

Resistive touch panels allow a single touch, although advances in new resistive technology will allow multi-touch operation in the near future. One main advantage of a resistive touch screen is the ability to be activated by the touch of any material. This includes a range of items from a bare finger, to a pencil, to even the edge of a credit card; regardless of its composition.

They also have the added advantage of operating in a wide temperature range and environments, including anything from the arctic cold of Alaska to the extreme heat of Death Valley.

Capacitive touch panels have become popular with such software as Windows 8®, Android® and Apple®. Additionally it is used in products such as cell phones and tablets, where multi-touch and zoom capabilities are important.

Current capacitive touch technology is limited to a conductive stylus such as a finger. The touch screen operates on capacitive sensing, based on capacitive coupling. A capacitive touch screen detects any material that is conductive or has a different dielectric then the air around it.

Contrast ratio, or static contrast ratio, is one way to measure the sharpness of the TFT LCD display. This ratio is the difference between the darkest black and the brightest white the display is able to produce. The higher the number on the left, the sharper the image. A typical contrast ratio for TFT may be 300:1. This number ratio means that the white is 300 times brighter than the black.

TFT LCD displays are measured in inches; this is the measurement of the diagonal distance across the glass. Common TFT sizes include: 1.77”, 2.4”, 2.8”, 3”, 4.3”, 5”, 5.7”, 5.8”, 7”, 10.2”, 12.1 and 15”.

As a general rule, the larger the size of the glass the higher the cost of the display, but there are exceptions to this rule. A larger display may be less expensive than a smaller display if the manufacture produces higher quantities of the larger displays. When selecting your color display, be sure to ask what the cost is for one size smaller and one size larger. It may be worth modifying your design requirements.

TFT resolution is the number of dots or pixels the display contains. It is measured by the number of dots along the horizontal (X axis) and the dots along the vertical (Y axis).

The higher the resolution, the more dots per square inch (DPI), the sharper the display will look. A higher resolution results in a higher cost. One reason for the increase in cost is that more driver chips are necessary to drive each segment.

Certain combinations of width and height are standardized and typically given a name and a letter representation that is descriptive of its dimensions. Popular names given to the TFT LCD displays resolution include:

Transmissive displays must have the backlight on at all times to read the display, but are not the best option in direct sunlight unless the backlight is 750 Nits or higher. A majority of TFT displays are Transmissive, but they will require more power to operate with a brighter backlight.

Transflective displays are readable with the backlight off provided there is enough ambient light. Transflective displays are more expensive than Transmissive also there may be a larger MOQ for Transflective. However, Transflective displays are the best option for direct sunlight.

Drivers update and refresh the pixels (Picture Elements) of a display. Each driver is assigned a set number of pixels. If there are more pixels than a single driver can handle, then an additional drivers are added.

A primary job of the driver is to refresh each pixel. In passive TFT displays, the pixel is refreshed and then allowed to slowly fade (aka decay) until refreshed again. The higher the refresh frequency, the sharper the displays contrast.

The controller does just what its name suggest. It controls the drivers. There is only one controller per display no matter how many drivers. A complex graphic display with several thousand pixels will contain one controller and several drivers.

The TFT display (minus touch screen/backlight) alone will contain one controller/driver combination. These are built into the display so the design engineer does not need to locate the correct hardware.

Response Time is the measurement of time it takes for a pixel/segment to change from black (OFF state) to white (ON state) and then back to black again. In other words, how fast the picture can be changed. A slow response time can result in the blurring of the picture in games, movies and even cad type programs.

If you do not see a Thin Film Transistor (TFT) Display module that meets your specifications, or you need a replacement TFT, we can build a custom TFT displays to meet your requirements. Custom TFTs require a one-time tooling fee and may require higher MOQs.

Ready to order samples for your TFT design? Contact one of our US-based technical support people today concerning your design requirements. Note: We can provide smaller quantities for samples and prototyping.