measure smartphone display screens factory

2023-01-03 12:32:11

What constitutes a great phone display? Is it the high resolution and pixel density? Well, that, and great screen quality test numbers, that"s why the Sony Xperia 1 IV specs with the 1644p 4K panel top our list. What about the high brightness and contrast that offer good outdoor visibility in the sun outdoors? That"s certainly important, but most of today"s flagships have HDR-certified panels that breach the 1000-nit barrier upwards to fit the standard, and their OLED tech ensures practically infinite contrast ratio, so it"s hard to pick on that merit alone.

Ditto for credible color gamut presentation, as per-unit display calibration is no longer a prerogative of Apple"s iPhones, while said HDR display flagships now cover both the standard RGB, and the wide P3 color gamut. Is it the actual white balance and DeltaE numbers then? It"s getting warmer, but throw in dynamically-adjusted refresh rate based on the content displayed, and you"ve narrowed it down to only a few choices when it comes to the best phone displays that we round up below.

Not only does Sony make the only phones with 4K display resolution, but it also calibrates them to a near perfect level. The flagship Sony Xperia 1 IV carries a 6.5" 4K display with the whopping 643 PPI pixel density, and our display benchmarks returned class-beating brightness, white balance and wide gamut color representation credibility levels, some of the best we"ve measured. Add the high dynamic refresh rate, and the Sony Xperia 1 IV has probably the best panel on a phone so far.

The CIE 1931 xy color gamut chart represents the set (area) of colors that a display can reproduce, with the sRGB colorspace (the highlighted triangle) serving as reference. The chart also provides a visual representation of a display"s color accuracy. The small squares across the boundaries of the triangle are the reference points for the various colors, while the small dots are the actual measurements. Ideally, each dot should be positioned on top of its respective square. The "x: CIE31" and "y: CIE31" values in the table below the chart indicate the position of each measurement on the chart. "Y" shows the luminance (in nits) of each measured color, while "Target Y" is the desired luminance level for that color. Finally, "ΔE 2000" is the Delta E value of the measured color. Delta E values of below 2 are ideal.

The Color accuracy chart gives an idea of how close a display"s measured colors are to their referential values. The first line holds the measured (actual) colors, while the second line holds the reference (target) colors. The closer the actual colors are to the target ones, the better.

The Grayscale accuracy chart shows whether a display has a correct white balance (balance between red, green and blue) across different levels of grey (from dark to bright). The closer the Actual colors are to the Target ones, the better.

Pay attention to that "brightest" part and the 1Hz-120Hz specs at the full 1440p resolution. Yes, that means that the S22 Ultra is equipped with the newest LTPO OLED display technology that allowed for both the record 1750nits of peak brightness, 15% less battery consumption than what"s on the S21/S21+, and the dynamically-allocated refresh rate that can go down to 1Hz when you are looking at static images, or rev up all the way to 120Hz when you scroll.

This brightness is what makes the S22 Ultra display, in particular, stand out, as the granularly adaptive refresh rate has been on Oppo and OnePlus phones before it.

If you are looking for the best foldable phone display, it"s again Oppo that delivers with its Find N line, rather than Samsung. We tested the Find N2"s display to be one of the most color-credible panel among all phones, not only bendy ones, and the brightest on a foldable phone.

As usual with Oppo, ever since its partnership with Pixelworks, there is a per-unit factory Delta E calibration, color-blindness presets, and camera-to-display wide color management system. The LTPO panel is factory-calibrated and delivers one of the best color credibility Delta measurements we"ve ever taken, with only Google"s Pixels being better here.

Moreover, the Find X5 Pro has the best white balance score, nearest to the 6500K reference point that means the screens colors are spot on in terms of warmth, neither too yellowish, nor cold and blueish. Adding the high typical or peak brightness levels, the company has managed to beat its own best phone displays record.

To take full advantage of its excellent display panel"s abilities, the Find X5 Pro employs a "multi-brightness color calibration," meaning that the screen is as color-credible in all lighting conditions, be it on the beach or in the dark.

Google managed to catch up with factory calibration and its Pixel 6 Pro display now delivers not only one of the most feature-rich panels in the Android universe - 1440p resolution, dynamic 120Hz refresh rate, and high brightness, but it is also in the top three in terms of color representation in our display benchmark database.

Birds of a feather, the OnePlus 10 Pro and Oppo Find X5 Pro, as they sport the same 6.7" 1440p LTPO OLED panel with dynamic refresh rate and individual display calibration at the factory level courtesy of the imaging specialists from Pixelworks. Thus, you get a near-perfect color accuracy, wide gamut coverage, and high average brightness, all for less than $900 barring any running OnePlus 10 Pro deals.

These measurements are made using Portrait Displays" CalMAN calibration software.The high dynamic refresh rate is the best thing that happened to mobile displays since the introduction of the OLED technology, and there is no looking back once you"ve tried it while browsing and scrolling. Here"s the answers on our question how does it all work exactly:

The display is also basically able to do what MEMC TVs do, automatically increasing frames in video to up the rate, and take better advantage of the high refresh rate even with content that is usually shot with 24fps or 30fps. Detailing the panel"s virtues in a blog post, the OnePlus CEO also mentioned that:

In order to reach industry-leading color accuracy standards, we have added an additional automatic color calibration machine to the production line. By adding an extra 30 seconds to the production time, each display panel is automatically calibrated for color accuracy before it’s released.

Apple"s finest finally found the 120Hz refresh feature (say that 3 times quickly) and if you are already invested in the iOS ecosystem, there is nothing better than the brightest, toughest displays on an iPhone so far, the one on the iPhone 14 Pro Max and iPhone 14 Pro.

Apple advertises it as having a record for a phone peak brightness level of 2000 nits, or more typical brightness of 1600 nits when consuming HDR content and 1000 nits otherwise. This is exactly what we measured and these displays are so advanced that only Samsung can make them at the moment with its 12th-gen OLED technology.

Say what you will about Google entering the fray here but the Pixels have very well calibrated displays and the new Pixel 6a is no exception. First off, its color credibility is better than the more established calibration champs here (just look at those DeltaE numbers below). It is also sufficiently bright, so if you are looking for a compact 5G Android phone with a great camera and display that won"t break the bank, the Pixel 6a would fit your narrative.

measure smartphone display screens factory

The iPhone 11 display has rounded corners that follow a beautiful curved design, and these corners are within a standard rectangle. When measured as a standard rectangular shape, the screen is 6.06 inches diagonally (actual viewable area is less).

measure smartphone display screens factory

The iPhone XS Max display has rounded corners that follow a beautiful curved design, and these corners are within a standard rectangle. When measured as a standard rectangular shape, the screen is 6.46 inches diagonally (actual viewable area is less).

measure smartphone display screens factory

Plant Screen Mobile (further denoted as PSM) was developed with Android Studio (Google Inc.) using the OpenCV-libraries for image processing and analysis tasks. It works on mobile phones with Android OS 4.0 (Ice Cream Sandwich). All computations were performed on a Samsung Galaxy S6 smartphone. An overview on the basic processing modes of PSM is illustrated in the flowchart in Fig. 1.

The main interface of Plant Screen Mobile displays a live image from the front camera at a maximum resolution of 1920 × 1080px (Fig. 2a). Images are either stored for later processing (e.g. to speed up image acquisition) or analyzed immediately with a given parameter set (Fig. 2b, c). In the latter case each implemented algorithm is directly applied to the live image, results are displayed on-the-fly and can be stored as masked images. In this mode no additional traits are computed. To reach the desired camera orientation PSM includes a level tool that uses the smartphone’s accelerometer. During adjustment tilt angles are continuously displayed and horizontal (top-view) or vertical (side-view) camera orientations are indicated as information on the live screen. If necessary the smartphone illumination headlight may be switched on to optimize capturing conditions. Different visualizations like single channel display in RGB (red, green, blue color space) or HSV (hue, saturation, value color space) and a color information tool for the screen center pixels help to judge the imaging situation and to parameterize the filters. If images are analyzed at a different time from acquisition or imported from other sources, PSM provides batch operation for multiple images with one of the pre-selected processing modes that will be explained in the following together with a pre-specified parameter set. Segmented image results are stored and computed traits, evaluation date, and time are exported to CSV files.

On-the-fly segmentation of a Virginia mallow plant (Sida hermaphrodita). a Image of a Sida plant; b live view image displaying the on-the-fly HSV-segmentation of the imaged seedling (live view image was taken from a slightly different angle); RGB-camera values are first converted into HSV color space and then binarized using the parametrization of the HSV-filter in c lower and upper thresholds of the HSV-filter are adjusted such that the resulting plant mask can be analyzed for projected leaf area and other plant traits

Single-channel thresholding When color is not the primary feature to distinguish between object and background, image segmentation via single-channel thresholding is a suitable method with respect to computational time and memory. We implemented three threshold operations that are employed on grayscale representation of the RGB color space: simple thresholding, adaptive thresholding, and OTSU’s method [19]. In simple thresholding intensity values of each image pixel are compared to a global threshold α resulting in a binary mask B with values of 1 indicating intensity values above α and 0 otherwise. These values are attributed to plant and non-plant pixels. This can be sufficient, if plants are homogeneously illuminated in front of a black background. In adaptive thresholding, which accounts for local variations in illumination, α is calculated separately for each pixel using the surrounding region of a preset size. The comparison is either based on averaged intensities (adaptive mean), or on the Gaussian weighted sum (adaptive Gaussian). In Otsu’s method threshold α is automatically calculated and applied to the entire image. The integral part is an estimation of α, which splits up the intensity distribution such that resultant distributions display low intra-variance and high inter-variance. If necessary, the image can be inverted before applying any threshold operation, e.g. to segment dark objects in front of a brighter background.

Greenness thresholding Many plant phenotyping applications require the segmentation of green plant tissue. Various suitable approaches with low computational costs have been introduced and tested in different application scenarios that compute greenness indices on the base of RGB channel intensities $I_{R } I_{G}$, and $I_{B}$ [20, 21]. We implemented three well-known greenness measures: the Green Chromatic Coordinate (GCC) [20], the Vegetative Index (VEG) [22] and the Excess Green Excess Red Index (ExGR) [23]. All indices can filtered by a single thresholding operation with parameterα. In these greenness definitions a pixel $I\left( {x,y} \right)$ at position (x y) is classified to B according to:

Each computed segmentation is post-processed in two steps. First, morphological operations (erosion and dilation) are applied to close small gaps and to remove small fragments. Then, components with an 8-connected neighborhood are identified and labeled. In this way, multiple objects like detached leaves are counted and analyzed at the same time. The estimation of projected leaf area is the key feature of PSM and the output are pixels counts for each segment. To ensure comparability between different measurements (e.g. in setups with a varying camera-to-plant distance) PSM allows for a pixel-to-area conversion. For this purpose the user needs to place a calibration target (e.g., checkerboard pattern [27]) at approximately the same distance as the plant object to be photographed. PSM automatically detects the pattern and calculates a conversion factor that is used to compute metric area values from pixel counts. Besides the estimation of projected leaf area, PSM also provides a number of additional measures, which are listed in Table 1. Analyzed traits are exported to a CSV file together with information on luminance (LUX) and GPS coordinates.

measure smartphone display screens factory

The screen, when combined with the touch element, is "the" major element of the user interface and as such we go to great lengths when testing screens during our review process to measure a displays quality by measuring Contrast Ratio, Color Calibration, Brightness and Sunlight Legibility.

LCD (Liquid Crystal Display) displays consist of a matrix of Liquid Crystals. Liquid Crystals do not emit light themselves and are reliant on some form of back-light to illuminate the whole display. As a result LCD displays can be very visible in direct sunlight.

IPS-LCDs provide a superior viewing angle and better color reproduction than non IPS-LCDs due to the layout of the LCD"s themselves. This has become a common display type for mid-range to high-end phones.

OLED & AMOLED utilizes "organic" LEDs which emits light and in the majority of cases does away with the need for the back-light of an LCD display resulting in a potentially thinner panel.

They consume less power as opposed to LCDs which always have the back-light on. When a pixel is "black" on a OLED/AMOLED display the pixel is truly off.

measure smartphone display screens factory

Today, many of us rely on our smartphones to communicate, work, and play. Therefore, it can be quite alarming when they begin to act strangely – especially if you can’t get your phone to turn on at all.

One of the most concerning issues to plague smartphone users is a black screen, often referred to as the “black screen of death.” However, despite the harsh name, this issue can be remedied in several ways.

If you’re in need of smartphone repair, NerdsToGo can help. Our expert team understands the inner workings of a wide variety of devices. We’ll determine the root of the problem to get your phone up and running again as quickly as possible. And, if you don’t have time to visit our storefront for your smartphone repairs, we’ll come to you!

measure smartphone display screens factory

Tests and Measurements the iPhone XS Max receives ourDisplayMate Best Smartphone Display Awardearning DisplayMate�s highest ever A+ grade by providing

A liquid-crystal display (LCD) is a flat-panel display or other electronically modulated optical device that uses the light-modulating properties of liquid crystals combined with polarizers. Liquid crystals do not emit light directlybacklight or reflector to produce images in color or monochrome.seven-segment displays, as in a digital clock, are all good examples of devices with these displays. They use the same basic technology, except that arbitrary images are made from a matrix of small pixels, while other displays have larger elements. LCDs can either be normally on (positive) or off (negative), depending on the polarizer arrangement. For example, a character positive LCD with a backlight will have black lettering on a background that is the color of the backlight, and a character negative LCD will have a black background with the letters being of the same color as the backlight. Optical filters are added to white on blue LCDs to give them their characteristic appearance.

LCDs are used in a wide range of applications, including LCD televisions, computer monitors, instrument panels, aircraft cockpit displays, and indoor and outdoor signage. Small LCD screens are common in LCD projectors and portable consumer devices such as digital cameras, watches, calculators, and mobile telephones, including smartphones. LCD screens have replaced heavy, bulky and less energy-efficient cathode-ray tube (CRT) displays in nearly all applications. The phosphors used in CRTs make them vulnerable to image burn-in when a static image is displayed on a screen for a long time, e.g., the table frame for an airline flight schedule on an indoor sign. LCDs do not have this weakness, but are still susceptible to image persistence.

The optical effect of a TN device in the voltage-on state is far less dependent on variations in the device thickness than that in the voltage-off state. Because of this, TN displays with low information content and no backlighting are usually operated between crossed polarizers such that they appear bright with no voltage (the eye is much more sensitive to variations in the dark state than the bright state). As most of 2010-era LCDs are used in television sets, monitors and smartphones, they have high-resolution matrix arrays of pixels to display arbitrary images using backlighting with a dark background. When no image is displayed, different arrangements are used. For this purpose, TN LCDs are operated between parallel polarizers, whereas IPS LCDs feature crossed polarizers. In many applications IPS LCDs have replaced TN LCDs, particularly in smartphones. Both the liquid crystal material and the alignment layer material contain ionic compounds. If an electric field of one particular polarity is applied for a long period of time, this ionic material is attracted to the surfaces and degrades the device performance. This is avoided either by applying an alternating current or by reversing the polarity of the electric field as the device is addressed (the response of the liquid crystal layer is identical, regardless of the polarity of the applied field).

Displays for a small number of individual digits or fixed symbols (as in digital watches and pocket calculators) can be implemented with independent electrodes for each segment.alphanumeric or variable graphics displays are usually implemented with pixels arranged as a matrix consisting of electrically connected rows on one side of the LC layer and columns on the other side, which makes it possible to address each pixel at the intersections. The general method of matrix addressing consists of sequentially addressing one side of the matrix, for example by selecting the rows one-by-one and applying the picture information on the other side at the columns row-by-row. For details on the various matrix addressing schemes see passive-matrix and active-matrix addressed LCDs.

LCDs are manufactured in cleanrooms borrowing techniques from semiconductor manufacturing and using large sheets of glass whose size has increased over time. Several displays are manufactured at the same time, and then cut from the sheet of glass, also known as the mother glass or LCD glass substrate. The increase in size allows more displays or larger displays to be made, just like with increasing wafer sizes in semiconductor manufacturing. The glass sizes are as follows:

The origins and the complex history of liquid-crystal displays from the perspective of an insider during the early days were described by Joseph A. Castellano in Liquid Gold: The Story of Liquid Crystal Displays and the Creation of an Industry.IEEE History Center.Peter J. Wild, can be found at the Engineering and Technology History Wiki.

In 1964, George H. Heilmeier, then working at the RCA laboratories on the effect discovered by Williams achieved the switching of colors by field-induced realignment of dichroic dyes in a homeotropically oriented liquid crystal. Practical problems with this new electro-optical effect made Heilmeier continue to work on scattering effects in liquid crystals and finally the achievement of the first operational liquid-crystal display based on what he called the George H. Heilmeier was inducted in the National Inventors Hall of FameIEEE Milestone.

The idea of a TFT-based liquid-crystal display (LCD) was conceived by Bernard Lechner of RCA Laboratories in 1968.dynamic scattering mode (DSM) LCD that used standard discrete MOSFETs.

On December 4, 1970, the twisted nematic field effect (TN) in liquid crystals was filed for patent by Hoffmann-LaRoche in Switzerland, (Swiss patent No. 532 261) with Wolfgang Helfrich and Martin Schadt (then working for the Central Research Laboratories) listed as inventors.Brown, Boveri & Cie, its joint venture partner at that time, which produced TN displays for wristwatches and other applications during the 1970s for the international markets including the Japanese electronics industry, which soon produced the first digital quartz wristwatches with TN-LCDs and numerous other products. James Fergason, while working with Sardari Arora and Alfred Saupe at Kent State University Liquid Crystal Institute, filed an identical patent in the United States on April 22, 1971.ILIXCO (now LXD Incorporated), produced LCDs based on the TN-effect, which soon superseded the poor-quality DSM types due to improvements of lower operating voltages and lower power consumption. Tetsuro Hama and Izuhiko Nishimura of Seiko received a US patent dated February 1971, for an electronic wristwatch incorporating a TN-LCD.

In 1972, the concept of the active-matrix thin-film transistor (TFT) liquid-crystal display panel was prototyped in the United States by T. Peter Brody"s team at Westinghouse, in Pittsburgh, Pennsylvania.Westinghouse Research Laboratories demonstrated the first thin-film-transistor liquid-crystal display (TFT LCD).high-resolution and high-quality electronic visual display devices use TFT-based active matrix displays.active-matrix liquid-crystal display (AM LCD) in 1974, and then Brody coined the term "active matrix" in 1975.

Hitachi also improved the viewing angle dependence further by optimizing the shape of the electrodes (Super IPS). NEC and Hitachi become early manufacturers of active-matrix addressed LCDs based on the IPS technology. This is a milestone for implementing large-screen LCDs having acceptable visual performance for flat-panel computer monitors and television screens. In 1996, Samsung developed the optical patterning technique that enables multi-domain LCD. Multi-domain and In Plane Switching subsequently remain the dominant LCD designs through 2006.South Korea and Taiwan,

In 2007 the image quality of LCD televisions surpassed the image quality of cathode-ray-tube-based (CRT) TVs.LCD TVs were projected to account 50% of the 200 million TVs to be shipped globally in 2006, according to Displaybank.Toshiba announced 2560 × 1600 pixels on a 6.1-inch (155 mm) LCD panel, suitable for use in a tablet computer,

Since LCDs produce no light of their own, they require external light to produce a visible image.backlight. Active-matrix LCDs are almost always backlit.Transflective LCDs combine the features of a backlit transmissive display and a reflective display.

CCFL: The LCD panel is lit either by two cold cathode fluorescent lamps placed at opposite edges of the display or an array of parallel CCFLs behind larger displays. A diffuser (made of PMMA acrylic plastic, also known as a wave or light guide/guiding plateinverter to convert whatever DC voltage the device uses (usually 5 or 12 V) to ≈1000 V needed to light a CCFL.

EL-WLED: The LCD panel is lit by a row of white LEDs placed at one or more edges of the screen. A light diffuser (light guide plate, LGP) is then used to spread the light evenly across the whole display, similarly to edge-lit CCFL LCD backlights. The diffuser is made out of either PMMA plastic or special glass, PMMA is used in most cases because it is rugged, while special glass is used when the thickness of the LCD is of primary concern, because it doesn"t expand as much when heated or exposed to moisture, which allows LCDs to be just 5mm thick. Quantum dots may be placed on top of the diffuser as a quantum dot enhancement film (QDEF, in which case they need a layer to be protected from heat and humidity) or on the color filter of the LCD, replacing the resists that are normally used.

WLED array: The LCD panel is lit by a full array of white LEDs placed behind a diffuser behind the panel. LCDs that use this implementation will usually have the ability to dim or completely turn off the LEDs in the dark areas of the image being displayed, effectively increasing the contrast ratio of the display. The precision with which this can be done will depend on the number of dimming zones of the display. The more dimming zones, the more precise the dimming, with less obvious blooming artifacts which are visible as dark grey patches surrounded by the unlit areas of the LCD. As of 2012, this design gets most of its use from upscale, larger-screen LCD televisions.

RGB-LED array: Similar to the WLED array, except the panel is lit by a full array of RGB LEDs. While displays lit with white LEDs usually have a poorer color gamut than CCFL lit displays, panels lit with RGB LEDs have very wide color gamuts. This implementation is most popular on professional graphics editing LCDs. As of 2012, LCDs in this category usually cost more than $1000. As of 2016 the cost of this category has drastically reduced and such LCD televisions obtained same price levels as the former 28" (71 cm) CRT based categories.

Today, most LCD screens are being designed with an LED backlight instead of the traditional CCFL backlight, while that backlight is dynamically controlled with the video information (dynamic backlight control). The combination with the dynamic backlight control, invented by Philips researchers Douglas Stanton, Martinus Stroomer and Adrianus de Vaan, simultaneously increases the dynamic range of the display system (also marketed as HDR, high dynamic range television or FLAD, full-area local area dimming).

A standard television receiver screen, a modern LCD panel, has over six million pixels, and they are all individually powered by a wire network embedded in the screen. The fine wires, or pathways, form a grid with vertical wires across the whole screen on one side of the screen and horizontal wires across the whole screen on the other side of the screen. To this grid each pixel has a positive connection on one side and a negative connection on the other side. So the total amount of wires needed for a 1080p display is 3 x 1920 going vertically and 1080 going horizontally for a total of 6840 wires horizontally and vertically. That"s three for red, green and blue and 1920 columns of pixels for each color for a total of 5760 wires going vertically and 1080 rows of wires going horizontally. For a panel that is 28.8 inches (73 centimeters) wide, that means a wire density of 200 wires per inch along the horizontal edge.

The LCD panel is powered by LCD drivers that are carefully matched up with the edge of the LCD panel at the factory level. The drivers may be installed using several methods, the most common of which are COG (Chip-On-Glass) and TAB (Tape-automated bonding) These same principles apply also for smartphone screens that are much smaller than TV screens.anisotropic conductive film or, for lower densities, elastomeric connectors.

Monochrome and later color passive-matrix LCDs were standard in most early laptops (although a few used plasma displaysGame Boyactive-matrix became standard on all laptops. The commercially unsuccessful Macintosh Portable (released in 1989) was one of the first to use an active-matrix display (though still monochrome). Passive-matrix LCDs are still used in the 2010s for applications less demanding than laptop computers and TVs, such as inexpensive calculators. In particular, these are used on portable devices where less information content needs to be displayed, lowest power consumption (no backlight) and low cost are desired or readability in direct sunlight is needed.

A comparison between a blank passive-matrix display (top) and a blank active-matrix display (bottom). A passive-matrix display can be identified when the blank background is more grey in appearance than the crisper active-matrix display, fog appears on all edges of the screen, and while pictures appear to be fading on the screen.

Displays having a passive-matrix structure are employing Crosstalk between activated and non-activated pixels has to be handled properly by keeping the RMS voltage of non-activated pixels below the threshold voltage as discovered by Peter J. Wild in 1972,

STN LCDs have to be continuously refreshed by alternating pulsed voltages of one polarity during one frame and pulses of opposite polarity during the next frame. Individual pixels are addressed by the corresponding row and column circuits. This type of display is called response times and poor contrast are typical of passive-matrix addressed LCDs with too many pixels and driven according to the "Alt & Pleshko" drive scheme. Welzen and de Vaan also invented a non RMS drive scheme enabling to drive STN displays with video rates and enabling to show smooth moving video images on an STN display.

Bistable LCDs do not require continuous refreshing. Rewriting is only required for picture information changes. In 1984 HA van Sprang and AJSM de Vaan invented an STN type display that could be operated in a bistable mode, enabling extremely high resolution images up to 4000 lines or more using only low voltages.

High-resolution color displays, such as modern LCD computer monitors and televisions, use an active-matrix structure. A matrix of thin-film transistors (TFTs) is added to the electrodes in contact with the LC layer. Each pixel has its own dedicated transistor, allowing each column line to access one pixel. When a row line is selected, all of the column lines are connected to a row of pixels and voltages corresponding to the picture information are driven onto all of the column lines. The row line is then deactivated and the next row line is selected. All of the row lines are selected in sequence during a refresh operation. Active-matrix addressed displays look brighter and sharper than passive-matrix addressed displays of the same size, and generally have quicker response times, producing much better images. Sharp produces bistable reflective LCDs with a 1-bit SRAM cell per pixel that only requires small amounts of power to maintain an image.

Segment LCDs can also have color by using Field Sequential Color (FSC LCD). This kind of displays have a high speed passive segment LCD panel with an RGB backlight. The backlight quickly changes color, making it appear white to the naked eye. The LCD panel is synchronized with the backlight. For example, to make a segment appear red, the segment is only turned ON when the backlight is red, and to make a segment appear magenta, the segment is turned ON when the backlight is blue, and it continues to be ON while the backlight becomes red, and it turns OFF when the backlight becomes green. To make a segment appear black, the segment is always turned ON. An FSC LCD divides a color image into 3 images (one Red, one Green and one Blue) and it displays them in order. Due to persistence of vision, the 3 monochromatic images appear as one color image. An FSC LCD needs an LCD panel with a refresh rate of 180 Hz, and the response time is reduced to just 5 milliseconds when compared with normal STN LCD panels which have a response time of 16 milliseconds.

Samsung introduced UFB (Ultra Fine & Bright) displays back in 2002, utilized the super-birefringent effect. It has the luminance, color gamut, and most of the contrast of a TFT-LCD, but only consumes as much power as an STN display, according to Samsung. It was being used in a variety of Samsung cellular-telephone models produced until late 2006, when Samsung stopped producing UFB displays. UFB displays were also used in certain models of LG mobile phones.

Twisted nematic displays contain liquid crystals that twist and untwist at varying degrees to allow light to pass through. When no voltage is applied to a TN liquid crystal cell, polarized light passes through the 90-degrees twisted LC layer. In proportion to the voltage applied, the liquid crystals untwist changing the polarization and blocking the light"s path. By properly adjusting the level of the voltage almost any gray level or transmission can be achieved.

In-plane switching is an LCD technology that aligns the liquid crystals in a plane parallel to the glass substrates. In this method, the electrical field is applied through opposite electrodes on the same glass substrate, so that the liquid crystals can be reoriented (switched) essentially in the same plane, although fringe fields inhibit a homogeneous reorientation. This requires two transistors for each pixel instead of the single transistor needed for a standard thin-film transistor (TFT) display. The IPS technology is used in everything from televisions, computer monitors, and even wearable devices, especially almost all LCD smartphone panels are IPS/FFS mode. IPS displays belong to the LCD panel family screen types. The other two types are VA and TN. Before LG Enhanced IPS was introduced in 2001 by Hitachi as 17" monitor in Market, the additional transistors resulted in blocking more transmission area, thus requiring a brighter backlight and consuming more power, making this type of display less desirable for notebook computers. Panasonic Himeji G8.5 was using an enhanced version of IPS, also LGD in Korea, then currently the world biggest LCD panel manufacture BOE in China is also IPS/FFS mode TV panel.

In 2015 LG Display announced the implementation of a new technology called M+ which is the addition of white subpixel along with the regular RGB dots in their IPS panel technology.

Most of the new M+ technology was employed on 4K TV sets which led to a controversy after tests showed that the addition of a white sub pixel replacing the traditional RGB structure would reduce the resolution by around 25%. This means that a 4K TV cannot display the full UHD TV standard. The media and internet users later called this "RGBW" TVs because of the white sub pixel. Although LG Display has developed this technology for use in notebook display, outdoor and smartphones, it became more popular in the TV market because the announced 4K UHD resolution but still being incapable of achieving true UHD resolution defined by the CTA as 3840x2160 active pixels with 8-bit color. This negatively impacts the rendering of text, making it a bit fuzzier, which is especially noticeable when a TV is used as a PC monitor.

In 2011, LG claimed the smartphone LG Optimus Black (IPS LCD (LCD NOVA)) has the brightness up to 700 nits, while the competitor has only IPS LCD with 518 nits and double an active-matrix OLED (AMOLED) display with 305 nits. LG also claimed the NOVA display to be 50 percent more efficient than regular LCDs and to consume only 50 percent of the power of AMOLED displays when producing white on screen.

Vertical-alignment displays are a form of LCDs in which the liquid crystals naturally align vertically to the glass substrates. When no voltage is applied, the liquid crystals remain perpendicular to the substrate, creating a black display between crossed polarizers. When voltage is applied, the liquid crystals shift to a tilted position, allowing light to pass through and create a gray-scale display depending on the amount of tilt generated by the electric field. It has a deeper-black background, a higher contrast ratio, a wider viewing angle, and better image quality at extreme temperatures than traditional twisted-nematic displays.

Some manufacturers, notably in South Korea where some of the largest LCD panel manufacturers, such as LG, are located, now have a zero-defective-pixel guarantee, which is an extra screening process which can then determine "A"- and "B"-grade panels.clouding (or less commonly mura), which describes the uneven patches of changes in luminance. It is most visible in dark or black areas of displayed scenes.

The zenithal bistable device (ZBD), developed by Qinetiq (formerly DERA), can retain an image without power. The crystals may exist in one of two stable orientations ("black" and "white") and power is only required to change the image. ZBD Displays is a spin-off company from QinetiQ who manufactured both grayscale and color ZBD devices. Kent Displays has also developed a "no-power" display that uses polymer stabilized cholesteric liquid crystal (ChLCD). In 2009 Kent demonstrated the use of a ChLCD to cover the entire surface of a mobile phone, allowing it to change colors, and keep that color even when power is removed.

Resolution The resolution of an LCD is expressed by the number of columns and rows of pixels (e.g., 1024×768). Each pixel is usually composed 3 sub-pixels, a red, a green, and a blue one. This had been one of the few features of LCD performance that remained uniform among different designs. However, there are newer designs that share sub-pixels among pixels and add Quattron which attempt to efficiently increase the perceived resolution of a display without increasing the actual resolution, to mixed results.

Spatial performance: For a computer monitor or some other display that is being viewed from a very close distance, resolution is often expressed in terms of dot pitch or pixels per inch, which is consistent with the printing industry. Display density varies per application, with televisions generally having a low density for long-distance viewing and portable devices having a high density for close-range detail. The Viewing Angle of an LCD may be important depending on the display and its usage, the limitations of certain display technologies mean the display only displays accurately at certain angles.

Temporal performance: the temporal resolution of an LCD is how well it can display changing images, or the accuracy and the number of times per second the display draws the data it is being given. LCD pixels do not flash on/off between frames, so LCD monitors exhibit no refresh-induced flicker no matter how low the refresh rate.

Color performance: There are multiple terms to describe different aspects of color performance of a display. Color gamut is the range of colors that can be displayed, and color depth, which is the fineness with which the color range is divided. Color gamut is a relatively straight forward feature, but it is rarely discussed in marketing materials except at the professional level. Having a color range that exceeds the content being shown on the screen has no benefits, so displays are only made to perform within or below the range of a certain specification.white point and gamma correction, which describe what color white is and how the other colors are displayed relative to white.

Brightness and contrast ratio: Contrast ratio is the ratio of the brightness of a full-on pixel to a full-off pixel. The LCD itself is only a light valve and does not generate light; the light comes from a backlight that is either fluorescent or a set of LEDs. Brightness is usually stated as the maximum light output of the LCD, which can vary greatly based on the transparency of the LCD and the brightness of the backlight. Brighter backlight allows stronger contrast and higher dynamic range (HDR displays are graded in peak luminance), but there is always a trade-off between brightness and power consumption.

Low power consumption. Depending on the set display brightness and content being displayed, the older CCFT backlit models typically use less than half of the power a CRT monitor of the same size viewing area would use, and the modern LED backlit models typically use 10–25% of the power a CRT monitor would use.

No theoretical resolution limit. When multiple LCD panels are used together to create a single canvas, each additional panel increases the total resolution of the display, which is commonly called stacked resolution.

As an inherently digital device, the LCD can natively display digital data from a DVI or HDMI connection without requiring conversion to analog. Some LCD panels have native fiber optic inputs in addition to DVI and HDMI.

Display motion blur on moving objects caused by slow response times (>8 ms) and eye-tracking on a sample-and-hold display, unless a strobing backlight is used. However, this strobing can cause eye strain, as is noted next:

As of 2012, most implementations of LCD backlighting use pulse-width modulation (PWM) to dim the display,CRT monitor at 85 Hz refresh rate would (this is because the entire screen is strobing on and off rather than a CRT"s phosphor sustained dot which continually scans across the display, leaving some part of the display always lit), causing severe eye-strain for some people.LED-backlit monitors, because the LEDs switch on and off faster than a CCFL lamp.

Only one native resolution. Displaying any other resolution either requires a video scaler, causing blurriness and jagged edges, or running the display at native resolution using 1:1 pixel mapping, causing the image either not to fill the screen (letterboxed display), or to run off the lower or right edges of the screen.

Fixed bit depth (also called color depth). Many cheaper LCDs are only able to display 262144 (218) colors. 8-bit S-IPS panels can display 16 million (224) colors and have significantly better black level, but are expensive and have slower response time.

Input lag, because the LCD"s A/D converter waits for each frame to be completely been output before drawing it to the LCD panel. Many LCD monitors do post-processing before displaying the image in an attempt to compensate for poor color fidelity, which adds an additional lag. Further, a video scaler must be used when displaying non-native resolutions, which adds yet more time lag. Scaling and post processing are usually done in a single chip on modern monitors, but each function that chip performs adds some delay. Some displays have a video gaming mode which disables all or most processing to reduce perceivable input lag.

Subject to burn-in effect, although the cause differs from CRT and the effect may not be permanent, a static image can cause burn-in in a matter of hours in badly designed displays.

Loss of brightness and much slower response times in low temperature environments. In sub-zero environments, LCD screens may cease to function without the use of supplemental heating.

Several different families of liquid crystals are used in liquid crystal displays. The molecules used have to be anisotropic, and to exhibit mutual attraction. Polarizable rod-shaped molecules (biphenyls, terphenyls, etc.) are common. A common form is a pair of aromatic benzene rings, with a nonpolar moiety (pentyl, heptyl, octyl, or alkyl oxy group) on one end and polar (nitrile, halogen) on the other. Sometimes the benzene rings are separated with an acetylene group, ethylene, CH=N, CH=NO, N=N, N=NO, or ester group. In practice, eutectic mixtures of several chemicals are used, to achieve wider temperature operating range (−10..+60 °C for low-end and −20..+100 °C for high-performance displays). For example, the E7 mixture is composed of three biphenyls and one terphenyl: 39 wt.% of 4"-pentyl[1,1"-biphenyl]-4-carbonitrile (nematic range 24..35 °C), 36 wt.% of 4"-heptyl[1,1"-biphenyl]-4-carbonitrile (nematic range 30..43 °C), 16 wt.% of 4"-octoxy[1,1"-biphenyl]-4-carbonitrile (nematic range 54..80 °C), and 9 wt.% of 4-pentyl[1,1":4",1-terphenyl]-4-carbonitrile (nematic range 131..240 °C).

The production of LCD screens uses nitrogen trifluoride (NF3) as an etching fluid during the production of the thin-film components. NF3 is a potent greenhouse gas, and its relatively long half-life may make it a potentially harmful contributor to global warming. A report in Geophysical Research Letters suggested that its effects were theoretically much greater than better-known sources of greenhouse gasses like carbon dioxide. As NF3 was not in widespread use at the time, it was not made part of the Kyoto Protocols and has been deemed "the missing greenhouse gas".

Castellano, Joseph A (2005). Liquid Gold: The Story of Liquid Crystal Displays and the Creation of an Industry. World Scientific Publishing. ISBN 978-981-238-956-5.

Rong-Jer Lee; Jr-Cheng Fan; Tzong-Shing Cheng; Jung-Lung Wu (March 10, 1999). "Pigment-dispersed color resist with high resolution for advanced color filter application". Proceedings of 5th Asian Symposium on Information Display. ASID "99 (IEEE Cat. No.99EX291). pp. 359–363. doi:10.1109/ASID.1999.762781. ISBN 957-97347-9-8. S2CID 137460486 – via IEEE Xplore.

Liquid Gold: The Story of Liquid Crystal Displays and the Creation of an Industry, Joseph A. Castellano, 2005 World Scientific Publishing Co. Pte. Ltd., ISBN 981-238-956-3.

Gray, George W.; Kelly, Stephen M. (1999). "Liquid crystals for twisted nematic display devices". Journal of Materials Chemistry. 9 (9): 2037–2050. doi:10.1039/a902682g.

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.

Hirohisa Kawamoto (2013), The history of liquid-crystal display and its industry, HISTory of ELectro-technology CONference (HISTELCON), 2012 Third IEEE, Institute of Electrical and Electronics Engineers, DOI 10.1109/HISTELCON.2012.6487587

Competing display technologies for the best image performance; A.J.S.M. de Vaan; Journal of the society of information displays, Volume 15, Issue 9 September 2007 Pages 657–666; http://onlinelibrary.wiley.com/doi/10.1889/1.2785199/abstract?

Pixel-by-pixel local dimming for high dynamic range liquid crystal displays; H. Chen; R. Zhu; M.C. Li; S.L. Lee and S.T. Wu; Vol. 25, No. 3; 6 Feb 2017; Optics Express 1973; https://www.osapublishing.org/oe/viewmedia.cfm?uri=oe-25-3-1973&seq=0

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measure smartphone display screens factory

The five most popular eligible general search services in each country according to StatCounter (including Google) will be displayed at the top, ordered randomly each time the choice screen is shown.

Up to seven remaining eligible general search services will be shown below the initial five services, similarly ordered randomly. In the event there are more than seven remaining general search services in a given country, the seven services to be shown on the choice screen in that country will be selected at random each time the choice screen is displayed.

General search provider: The search provider must operate a “general search service.” For purposes of the choice screen, a general search service is one that allows users to search for information across the entire Internet. Specialized or “vertical” search providers -- those that only index content from a particular subject -- are not eligible to participate in the choice screen. Search providers that are owned by or affiliated with the same company are eligible to appear on the choice screen only once in each country. Companies that syndicate Google search results or ads and display them in their apps or webpages on Android mobile devices to users in one or more EEA countries or the UK are not eligible to participate.

The StatCounter data used to determine the initial set of five eligible general search services will be refreshed annually. The order in which participating services are displayed in the choice screen is randomised each time the choice screen is shown, as explained above.

Yes, so long as the service otherwise qualifies as a bona fide “general search service,” as defined above. Note that companies that have a syndication agreement with Google are not currently eligible to participate if they syndicate Google search results or ads and display them in their apps or webpages on Android mobile devices in EEA/UK countries.

The choice screen will only be displayed on devices where the OEM has elected to pre-install the Google Search app. On devices where rival search providers are exclusively pre-installed, the choice screen will not be displayed.

measure smartphone display screens factory

Could you last a day without your cell phone? As many as 84% of U.S. residents could not, according to a recent poll conducted by Time magazine. It is hard to believe that 20 years ago, hardly anyone even owned a cell phone. And now the cell phone has morphed into something bigger and better—the smartphone. Worldwide, more than one billionsmartphones were purchased last year. If you own a smartphone, you are probably aware that in a year or two, it will be practically obsolete, because the smartphone just keeps getting smarter.

In the 1950s, you would have needed a whole bank of computers on an entire floor of an office building to do what you are able to do with a single smartphone today. Even a low-end smartphone has more computing power than the computer system the National Aeronautics and Space Administration (NASA) used to put a man on the moon. Amazingly, you can surf the Internet, listen to music, and text your friends with something that fits in the palm of your hand. None of this would be possible without chemistry, and every time you use your smartphone, you are putting chemistry into action.

If you are wondering what chemistry has to do with smartphones, just look at the periodic table. Of the 83 stable (nonradioactive) elements, at least 70 of them can be found in smartphones! That’s 84% of all of the stable elements.

Metals are what make smartphones so “smart.” An average smartphone may contain up to 62 different types of metals. One rather obscure group of metals—the rare-earth metals—plays a vital role. These rare-earth metals include scandium and yttrium, as well as elements 57–71. Elements 57–71 are known as the lanthanides, because they begin with the element lanthanum. The lanthanides often appear as the first of two free-floating rows located at the bottom of the periodic table. Scandium and yttrium are included in the rare-earth metals because their chemical properties are similar to those of the lanthanides.

A single iPhone contains eight different rare-earth metals. If you examine several varieties of smartphones, you can find 16 of the 17 rare earth metals. The only one you will not find is promethium, which is radioactive.

Rare-earth metals are not only used in smartphones but in many other high-tech devices, too. They are found in televisions, computers, lasers, missiles, camera lenses, fluorescent light bulbs, and catalytic convertors. Rare-earth elements are so important in the electronics, communications, and defense industries that the U.S. Department of Energy dubbed them the “technology metals.”

When shopping for a smartphone, the single most important feature that people look for is the display. The screen allows you to see the phone’s display. If you have ever dropped your phone without damaging the screen, you were probably relieved. Smartphone screens are designed to be extremely tough.

This amazing glass-ceramic material is so resistant to heat that it has been used in the nose cones of supersonic-guided missiles used by the military. As a result of the success of glass-ceramic materials, the Corning Glass Works Company undertook a large research effort to find ways to make ordinary transparent glass as strong as glass-ceramic products. By 1962, Corning had developed a very strong type of chemically strengthened glass, unlike anything ever seen before. This super-strong glass would eventually make its way to nearly every smartphone screen. It is so strong it goes by the name, Gorilla Glass. Laboratory tests have shown that Gorilla Glass can withstand 100,000 pounds of pressure per square inch!

Figure 2. Gorilla Glass, which is used in smartphone displays, is a type of glass that is strengthened by the addition of potassium ions, which replace smaller sodium ions. (Note: This drawing is for illustration purposes only.)

As every smartphone user knows, the screen on a smartphone is far more than just a tough piece of glass. It is a screen that responds to your touch—aptly named a touchscreen—giving you a personal connection to your phone.

There are two basic categories of touchscreens. The first category of touchscreens, called resistive touchscreens, can be touched with any type of material and they will still work. A pencil works just as well as a finger. You can activate the screen even if wearing gloves. Resistive touchscreens are found in an automated teller machine (ATM) and at checkout counters in stores, where you sign your name for a credit purchase on the display screen.

Resistive touchscreens are composed of two thin layers of conductive material under the surface (Fig. 3). When you press down a resistive touchscreen, it physically indents, causing the two layers to touch, completing the circuit and changing the electrical current at the point of contact. The software recognizes a change in the current at these coordinates and carries out the action that corresponds with that spot. Resistive touchscreens are also known as pressure-sensitive screens. Only one button at a time can be pressed. If two or more buttons are pressed at once, the screen does not respond.

Figure 3. When a finger presses down on a resistive touchscreen, the top and bottom resistive circuit layers are pressed against each other, causing the two transparent metal coatings (left and right) to touch. This leads to a change in the electrical current at the point of contact, which allows a controller within the smartphone to determine the position of the point of contact.

Smartphones use the second basic category of touchscreens, called capacitive touchscreens (Fig. 4), which are electrical in nature. A capacitor is any device that stores electricity.

Figure 4. When a finger presses down on a capacitive touchscreen, a very small electrical charge is transferred to the finger, creating a voltage drop on that point of the screen. A controller within the smartphone processes the

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